JP2003344634A - Band-pass filter for liquid crystal display, liquid crystal display using the same, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a band-pass filter for a liquid crystal display which permits the thinning, and which does not cause the deterioration in the optical property or the reliability. <P>SOLUTION: The band-pass filter 10 made of a band-pass filter layer 2 for selectively transmitting light is formed by a sticking step for sticking the band- pass filter layer 2 formed on a support base 1 to an optical device 3 constituting the liquid crystal display, and a transfer step for exfoliating the support base 1 from the band-pass filter layer 2 and for transferring the band-pass filter layer 2 to the optical device 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bandpass filter for a liquid crystal display device (an optical element for collimating light emitted from a backlight constituting the liquid crystal display device by selectively transmitting the light), and more particularly, The present invention relates to a bandpass filter that can be thinned and can be expected to prevent deterioration of optical characteristics and deterioration of reliability.

[0002]

2. Description of the Related Art EL (electroluminescence element) backlights, CCFL (cold cathode fluorescent tube) backlights, LEDs (light emitting diodes) used in liquid crystal display devices.
A backlight or the like usually has a peak at a specific wavelength.

Therefore, if a band-pass filter that allows light having a specific peak wavelength emitted from the backlight to pass through at the time of vertical incidence and reflects at the time of oblique incidence is disposed on the emission surface side of the backlight, the vertically incident light is transmitted. However, incident light from an oblique direction is reflected without being transmitted, and parallelization is possible.

The bandpass filter is formed by vacuum vapor deposition or electron beam co-evaporation (EB), is also formed by precision coating of cholesteric liquid crystal, or is a stretched film of a resin material extruded in multiple layers, or It is formed by laminating multiple layers of resin material by precision thin film coating.

Most of the bandpass filters formed by vapor deposition are formed by vapor depositing a bandpass filter layer on a supporting substrate such as a glass substrate or a thick film. Here, from the viewpoint of being able to withstand deformation and breakage due to internal stress of the bandpass filter layer (deposition layer), it is necessary to make the supporting base material thick to some extent, so the thickness of the bandpass filter layer itself is as thin as several μm. However, under the present circumstances, the entire bandpass filter including the supporting base material becomes thick, and the thickness of the bandpass filter is restricted by the thickness of the supporting base material.

[0006] In the vapor-deposited product such as the band-pass filter, since the vapor-deposited layer is not flexible and internal stress remains, it is difficult to peel it from the supporting base material, and it is impossible to force it. If peeled off, the vapor deposition layer is often destroyed.

In a bandpass filter formed by multi-layer extruding resin materials having different refractive indexes and then stretching, the thickness of the band-pass filter layer itself after stretching becomes about several tens of μm, and a thinner layer than this. It is difficult to convert. This is because, if it is attempted to make the layer thinner, variations in optical characteristics due to breakage or stretching unevenness are likely to occur during stretching.

In a bandpass filter formed by precision coating cholesteric liquid crystal, the thickness of the bandpass filter layer itself is only about several μm, but with precision coating,
In controlling the liquid crystal alignment, good quality cannot be obtained unless it is applied to a supporting base material having a thickness of about several tens of μm. This means that in order to obtain the surface smoothness required for precision coating and control of liquid crystal orientation, the thickness of the supporting base material must be increased, and when the precision coating film (bandpass filter layer) is cured. In order for the supporting substrate to withstand the stress of
This is because it is necessary to have a thickness of about 8 to 100 μm, and if a film having a thickness of several μm is used as a supporting base material, the strength cannot be endured.

Also in the case of a bandpass filter formed by laminating multiple resin materials having different refractive indexes by precision thin film coating, the thickness of the bandpass filter layer itself is several μm.
Although only to some extent, the thickness of the supporting base material is required to be about several tens of μm for the same reason as the bandpass filter formed by precisely coating the cholesteric liquid crystal.

As described above, the bandpass filter as a means for collimating the light emitted from the backlight is another collimating means having a thickness of several tens of μm or more, such as a micro prism sheet or a light shielding louver. There was no substantial difference in terms of thickness as compared with.

Therefore, a very strict requirement for the thickness of an optical device (optical film) for a liquid crystal display device in recent years (for example, in a liquid crystal display device used for a mobile phone, reductions of 10 μm are required to be accumulated. In view of the above, there is a problem that using a bandpass filter as a collimating means does not provide much advantage from the viewpoint of thinning.

Further, the bandpass filter formed by precisely coating the cholesteric liquid crystal and the bandpass filter formed by laminating multiple resin materials having different refractive indexes by precision thin film coating are used for a long period of time. In a high-temperature and high-humidity environment, even though the bandpass filter layer itself that exerts an optical function can withstand, depending on the type of support substrate, the support substrate itself cannot withstand, resulting in reliability as a bandpass filter. There is also a problem that is often damaged. Furthermore, biaxially stretched P having residual birefringence
As in the case where the support substrate is formed by ET or the like, deterioration of optical characteristics due to the support substrate itself may be a problem.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior arts described above, and it is possible to make the device thinner, and at the same time, the optical characteristics are deteriorated and the reliability is lowered. It is an object to provide a bandpass filter for a liquid crystal display device that can be expected not to exist.

[0014]

In order to solve the above-mentioned problems, the present invention provides a band-pass filter comprising a band-pass filter layer for selectively transmitting light as defined in claim 1, which comprises a support substrate. A bandpass filter layer formed on a material, a bonding step of bonding to an optical device that constitutes a liquid crystal display device, and peeling the supporting base material from the bandpass filter layer to form the bandpass filter layer. A bandpass filter for a liquid crystal display device, which is formed by a transfer step of transferring to the optical device.

According to the first aspect of the present invention, the supporting base material (corresponding to a conventional bandpass filter) on which the bandpass filter layer is formed is used as an optical device (polarizing plate or phase difference filter) constituting a liquid crystal display device. (A plate or the like), then only the supporting base material is peeled off, and the bandpass filter layer is transferred to the optical device, whereby a bandpass filter composed of the bandpass filter layer (without the supporting base material) is formed. It is formed. Therefore, the band-pass filter according to the present invention does not have a supporting base material like the conventional band-pass filter, and the thickness is increased, the optical characteristics are deteriorated, and the reliability is lowered due to the supporting base material. Can be prevented.
Since the band-pass filter according to the present invention is premised on the peeling and removal of the supporting base material, it is not necessary to consider the thickness of the supporting base material, and the surface smoothness, thermal history during surface treatment, tension, and vibration. It is possible to use a thick supporting base material in consideration of such influences. Further, since it becomes possible to use a thick supporting base material, it is possible to enhance the handling property. Furthermore, in order to prevent malfunctions in an automatic laminating machine that can be used when laminating a supporting substrate having a bandpass filter layer formed on an optical device, the automatic laminating machine ensures that each film is individually processed. Since the thickness of the supporting base material can be given so as not to fall below the lower limit of the thickness that can be picked up, it is possible to reduce work mistakes during manufacturing of the liquid crystal display device, which in turn contributes to cost reduction by improving yield. It is possible.

Preferably, the bandpass filter layer is formed by applying a precise thin film of cholesteric liquid crystal on a supporting base material as in claim 2, and refracting light in each case as in claim 3. It may be formed by laminating multiple layers of resin materials having different rates on a supporting substrate by precision thin film coating.

A bandpass filter layer obtained by applying a precision thin film coating of cholesteric liquid crystal on a supporting base material, or a resin material having a different refractive index is formed on the supporting base material by multi-layer lamination by precision thin film coating. The bandpass filter layer is
It has the advantage that flexibility is easily imparted and that the bandpass filter layer is easily peeled from the supporting base material and transferred to the optical member.

Preferably, the bandpass filter is formed by attaching the optical device that has undergone the attaching step to a liquid crystal cell of the liquid crystal display device and then performing the transferring step. To be done.

According to the invention of claim 4, the bandpass filter layer is used as a supporting substrate until the optical device (polarizing plate, retardation plate, etc.) which has undergone the attaching step is attached to the liquid crystal cell of the liquid crystal display device. Will be protected by. That is, the supporting base material has the function of protecting the surface of the bandpass filter layer, and it is necessary to newly attach the surface protection film or the like to the bandpass filter layer after peeling the supporting base material and the bandpass filter layer. There is an advantage that there is no. Further, considering that optical devices such as a polarizing plate and a retardation plate have become thinner, and depending on their type, they may be thinner than the supporting base material or inferior in mechanical strength. The bandpass filter according to claim 4 has an advantage in that it is not easily affected by the strength.

Preferably, the supporting base material is subjected to an antistatic treatment as described in claim 5.

According to the invention of claim 5, it is possible to prevent the generation of static electricity when the supporting base material is peeled from the bandpass filter layer, and to destroy the peripheral electronic material constituting the liquid crystal display device or to remove dust. Adhesion can be suppressed. The invention according to claim 5 is a TFT (Thin Film Transistor).
In addition to liquid crystal display devices that are sensitive to static electricity, such as liquid crystal display devices,
It is particularly useful when a semiconductor is formed on a liquid crystal cell such as a COG (Chip On Glass) system or a polysilicon TFT.

Preferably, the antistatic treatment has a surface resistance value of 10 ¹² Ω on the supporting base material.
It is applied by forming the following antistatic layer. The surface resistance value is more preferably 10 ¹⁰ Ω or less, further preferably 10 ⁸ Ω or less.

According to the present invention, as described in claim 7,
A backlight comprising a liquid crystal cell having the optical device having the bandpass filter layer according to any one of claims 1 to 6 attached thereto and a light source having a bright line spectrum, and emitting light toward the liquid crystal cell. It is also provided as a liquid crystal display device comprising:

Further, according to the present invention, as described in claim 8,
A method of manufacturing a bandpass filter for a liquid crystal display device, which comprises a bandpass filter layer for selectively transmitting light, wherein the bandpass filter layer formed on a supporting base material,
And a transfer step of separating the supporting base material from the bandpass filter layer and transferring the bandpass filter layer to the optical device. And a method of manufacturing a bandpass filter for a liquid crystal display device.

It is preferable that the optical device which has been subjected to the attaching step is attached to the liquid crystal cell of the liquid crystal display device, and then the transferring step is performed.

[0026]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view illustrating a method of manufacturing a bandpass filter according to an embodiment of the present invention. Figure 1
As shown in, the bandpass filter 1 according to the present embodiment
In order to manufacture 0, first, the band-pass filter layer 2 (FIG. 1) formed on the supporting substrate 1 for selectively transmitting light is used.
(a)) is attached to an optical device (polarizing plate, retardation plate, etc.) 3 that constitutes a liquid crystal display device (FIG. 1 (b)). Next, the support base material 1 is peeled off from the bandpass filter layer 2 and the bandpass filter layer 2 is transferred to the optical device 3, whereby the bandpass filter 10 composed of the bandpass filter layer 2 is formed ( Figure 1 (c)).

As described above, after the support base material 1 on which the bandpass filter layer 2 is formed is attached to the optical device 3,
By removing only the supporting base material 1 and transferring the bandpass filter layer 2 to the optical device 3, the bandpass filter 10 composed of the bandpass filter layer 2 is formed. Therefore, the bandpass filter 1 according to the present embodiment
0 is a supporting substrate 1 like a conventional bandpass filter.
It is possible to prevent an increase in thickness, deterioration of optical characteristics, and deterioration of reliability due to the supporting base material 1. The bandpass filter 10 is attached to a liquid crystal cell (not shown) together with the optical device 3, and a backlight (not shown) for irradiating the liquid crystal cell is further incorporated to produce a liquid crystal display device. It is possible to

The bandpass filter layer 2 shown in FIG.
Is formed by laminating resin materials having different refractive indexes onto the supporting base material 1 in multiple layers by precision thin film coating, or by forming a cholesteric liquid crystal on the supporting base material 1 by precision thin film coating. . Hereinafter, this will be described more specifically.

(1) When laminating resin materials to form a bandpass filter layer For example, polyethylene naphthalate, polyethylene terephthalate, polycarbonate, vinylcarbazole,
A halogenated resin composition represented by brominated acrylate, a high refractive index resin material such as a high refractive index inorganic material ultrafine particle embedded resin composition, a fluororesin material represented by trifluoroethyl acrylate, or a polyresin A low refractive index resin material such as an acrylic resin typified by methyl methacrylate is used, and materials having different refractive indexes are used as the supporting substrate 1.
The band pass filter layer 2 can be formed by stacking the layers on top.

(2) When forming a bandpass filter layer using cholesteric liquid crystal For example, a thin film for obtaining selective reflection having a cholesteric spiral structure is formed on the supporting substrate 1 by using lyotropic liquid crystal or thermotropic liquid crystal. Such a thin film can be subjected to treatments such as UV polymerization, drying, and heat curing to fix the structure to form the bandpass filter layer 2.

The supporting base material 1 is not particularly limited in its material as long as it can precisely and accurately form the bandpass filter layer 2, but a resin film is generally used. Examples of the resin film include cellulose-based polymers such as cellulose diacetate and triacetate, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, films made of polyolefin-based or polycarbonate-based polymers, and the like, which have excellent surface smoothness. A film having few defects is preferably used.

Further, since the supporting base material 1 is finally removed, there is no upper limit of the thickness, and it is possible to intentionally use the thick supporting base material 1 according to the size in order to improve the handling property. It is possible.

For example, a supporting substrate 1 having a diagonal of about 10 inches
Then, the handling can be easily performed even when the thickness is 200 μm or less, but if the supporting base material 1 has a diagonal size of about 40 inches, the supporting base material 1 has a large deflection under its own weight at a thickness of about 200 μm, which makes the handling difficult. Therefore, if the supporting base material 1 is given a thickness of, for example, about 1 mm, the supporting base material can function as a supporting base material until the end of handling, and an excellent advantage in handling property (productivity) can be obtained. After being attached to the optical device 3, it is peeled off and removed, so that the thinning of the liquid crystal display device is not adversely affected.

It should be noted that the supporting base material 1 is prevented from generating static electricity when the supporting base material 1 is peeled from the bandpass filter layer 2 and prevents the peripheral electronic materials constituting the liquid crystal display device from being destroyed or dust from being attached. From the viewpoint of suppressing, it is preferable to perform antistatic treatment. The method of such antistatic treatment is not limited, but a permanent antistatic treatment film is formed as the antistatic layer from the viewpoint that the antistatic layer does not fall off due to handling and contamination of peripheral electronic materials and the like does not occur. Is desirable. Such a permanent antistatic treatment film is preferably formed, for example, by applying a resin film in which conductive fine particles are embedded on the supporting base material 1 to form a film.

The optical device 3 is a polarizing plate or a retardation plate. The material and type of the optical device 3 are not particularly limited, but when the optical device 3 is a retardation plate,
In addition to stretched products of polycarbonate film, alignment coated products of liquid crystal polymers and the like are preferably used. The surface of the optical device 3 is preferably subjected to saponification or corona treatment for easy adhesion.

The bandpass filter layer 2 is replaced with the optical device 3
Although the material for the adhesive to be adhered to is not limited, an acrylic or epoxy adhesive material or adhesive having excellent transparency and reliability is preferably used.
The thickness of the adhesive is preferably thin, but is usually 25 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less and 0.5 μm or more.

Next, the setting of the selective transmission wavelength in the bandpass filter 10 will be described in detail.

The bandpass filter 10 according to the present embodiment.
Is a backlight (not shown) that constitutes a liquid crystal display device.
On the other hand, the maximum transmittance is shown at a wavelength corresponding to the peak wavelength in the emission spectrum of (the wavelength showing the maximum transmittance is referred to as the maximum transmittance wavelength), while the reflection wavelength (reflected wavelength of 50% or more on the longer wavelength side than the maximum transmittance wavelength (reflection (Wavelength at which the ratio is 50% or more).

Here, as will be described later, the parallelism of the light passing through the bandpass filter 10 differs depending on the difference between the reflection wavelength and the maximum transmission wavelength, and the difference is arbitrarily set according to the purpose. Can be set.

That is, the reflection wavelength with a cut rate of 50% or more according to the incident angle θ of the light on the bandpass filter 10 is approximately derived by the following equation (1). λ2 = λ1 × (1- (n0 / ne) ² × sin ² θ) ^1/2 (1) where λ1 is the value of the reflected wavelength that reflects 50% or more of the vertically incident light, and λ2 is the incident wavelength. The value of the reflection wavelength that reflects 50% or more of the light of the angle θ, n0 is the refractive index of the external medium (1.0 in the case of the air interface), ne is the effective refractive index of the bandpass filter 10, and θ is The incident angles are shown respectively.

From the above formula (1), for example, for the peak wavelength of 545 nm in the emission spectrum of the backlight, the reflection wavelength λ1 = 555 nm, the bandpass filter 1
When the effective refractive index of 0 is ne = 2.0 and the air interface is left, the incident angle θ becomes the reflection wavelength λ2 = 545 nm.
Is about ± 22 degrees. That is, the incident angle θ is about ±
If it is within the range of 22 degrees, it is possible to obtain a transmittance of 50% or more (on the contrary, if the incident angle θ is outside the range of about ± 22 degrees, then λ2 <545 nm, which is on the longer wavelength side than λ2. The light having a peak wavelength of 545 nm of the backlight is
It means that 50% or more of the light does not pass through the bandpass filter 10). Similarly, the reflection wavelength λ1 = 547 nm
Then, the incident angle θ at which the reflection wavelength λ2 = 545 nm is about ± 10 degrees, and when the reflection wavelength λ1 = 545.5 nm, the incident angle θ at which the reflection wavelength λ2 = 545 nm is about ±.
It will be about 5 degrees.

In this way, the bandpass filter 10
By setting the maximum transmission wavelength (peak wavelength in the emission spectrum of the backlight) and the reflection wavelength λ1, the parallelism of the light transmitted through the bandpass filter 10 can be freely controlled.

When there are a plurality of peak wavelengths in the emission spectrum of the backlight, the same setting may be made for each wavelength. For example, in the case of a backlight that uses a three-wavelength cold cathode tube as a light source, the blue light is 43
5 nm, 545 nm for green light, 6 for red light
It often has a peak wavelength of 10 nm, and the reflection wavelength λ1 of the bandpass filter 10 may be set corresponding to each peak wavelength.

Further, the maximum transmittance for each wavelength in the bandpass filter 10 can be changed by designing the film quality, but in order to adjust the color tone of the transmitted light, the phosphor of each color of the light source forming the backlight is adjusted. Of the light source (plural light emitting diodes) for forming the backlight, or adjusting the power supplied to each light emitting diode forming the backlight. By doing so, it is possible to make the emission spectrum intensity of the backlight suitable for the maximum transmittance for each wavelength.

In the case of the bandpass filter 10 formed by using the cholesteric liquid crystal material, the angle characteristic of selective reflection in the cholesteric liquid crystal is described in Japanese Patent Application No. 2001-2001.
As disclosed in Japanese Patent Application No. 60005 and Japanese Patent Application No. 2000-281382, the wavelength band Δλ of selectively reflected light is derived from the following formula (3) from the difference Δn in average refractive index of cholesteric liquid crystals. Δλ = Δn × P × cos θ (3) Here, P represents the pitch interval of the cholesteric liquid crystal helical structure, and θ represents the incident angle. Therefore, the above equation (3)
Based on the above, it is possible to design and control the parallelism of transmitted light as in the case of the bandpass filter described above.

In this embodiment, after the bandpass filter layer 2 formed on the supporting substrate 1 is attached to the optical device 3, the supporting substrate 1 is immediately moved to the bandpass filter layer 2.
Although the bandpass filter 10 obtained by peeling from the above is described, the bandpass filter according to the present invention is not limited to this. For example, after attaching the bandpass filter layer 2 to the optical device 3, the optical device 3 is further attached to a liquid crystal cell that constitutes a liquid crystal display device, and then the supporting substrate 1 is peeled from the bandpass filter layer 2. It is also possible to form a band pass filter.

According to this aspect, the bandpass filter layer 2 is protected by the supporting substrate 1 until the optical device 3 that has undergone the attaching step is attached to the liquid crystal cell. That is, the support base material 1 has a function of protecting the surface of the bandpass filter layer 2, and after the support base material 1 and the bandpass filter layer 2 are peeled off, a new surface protection film or the like is added to the bandpass filter layer 1. It has the advantage that there is no need to attach. Further, considering that the optical device 3 such as a polarizing plate or a retardation film is also thinned, and depending on its type, the optical device 3 may be thinner than the supporting base material 1 or may be inferior in mechanical strength, the optical device 3 may be easy to handle. It is also advantageous in that it is unlikely to be affected by the mechanical strength of.

The features of the present invention will be further clarified by showing examples below.

Example 1 First, by applying a thin film of a cholesteric liquid crystal polymer, the selective reflection wavelength bands are 440 nm to 490 nm and 550 to 6 with respect to the emission spectra of 435 nm, 545 nm and 610 nm of a three-wavelength cold cathode tube.
A selective reflection circularly polarizing film that reflects right circularly polarized light at 00 nm and 615 to 700 nm was produced.

In the production of the film, the description in European Patent Application Publication No. 834754 is taken into consideration, and the selective reflection center wavelengths are 480 nm (blue) and 560, respectively.
nm (green) and 655 nm (red)
A polymeric liquid crystal mixture of the species was prepared. Specifically, first,
A nematic monomer A represented by the following chemical formula 1 and a chiral monomer B represented by the following chemical formula 2 (which have a mirror image symmetry with those described in EP-A-834754), respectively. Synthesized.

[Chemical 1]

[Chemical 2]

Next, the liquid crystal compositions A and B were mixed in the following mixing ratio according to the respective selective reflection central wavelengths. That is, with respect to the selective reflection center wavelength of 480 nm, the composition A
/ Composition B = 9.81 and selective reflection center wavelength 560 nm
For composition A / composition B = 11.9, and for selective reflection center wavelength 655 nm, composition A / composition B
= 14.8, they were mixed.

Each of the above mixtures was made into a 33% by weight solution of tetrahydrofuran, purged with nitrogen under an environment of 60 ° C., and 0.5% by weight of a reaction initiator (azobisisobutyronitrile) was added to carry out a polymerization treatment. I went. The polymer thus obtained was purified by reprecipitation separation with diethyl ether.

The supporting base material coated with the polymer is
A PET film having a thickness of 75 μm was used. A PVA layer of about 0.1 μm was applied to the surface of this supporting substrate, and rubbing was performed with a rubbing cloth made of rayon.

A 10% by weight solution of methylene chloride in the polymer was applied onto the supporting substrate by a wire bar so that the thickness when dried was about 1 μm. After coating, it was dried at 140 ° C. for 15 minutes. After the completion of this drying treatment, the liquid crystal was cooled and fixed at room temperature to obtain a liquid crystal thin film.

With respect to each of the polymers polymerized at each of the above mixing ratios, through the steps described above, liquid crystal thin films of RGB colors corresponding to the respective selective reflection central wavelengths were produced, and the transparent isosiate adhesive AD244 (special They were attached to each other by a color material industry company. More specifically, after the red and green liquid crystal surfaces are bonded together, the green PET film is peeled off, and in the same manner, the blue and green liquid crystal surfaces are bonded together, and then the red PET film is bonded. Was peeled off. As a result, three layers of each liquid crystal thin film are sequentially laminated from the short wavelength side, and a selective reflection circularly polarizing film having a liquid crystal composite layer with a thickness of about 5 μm (the supporting base material is a PET film coated with a blue liquid crystal thin film). Was produced. The transmission spectral characteristics of the selective reflection circularly polarizing film produced as described above are shown in FIG.

On the other hand, a polarizing plate with a NIPOCS film (NIPO manufactured by Nitto Denko Corporation) having a function of reflecting left circularly polarized light
CS film: PCF400, Polarizing plate: TEG1465
DU), corona treatment is applied to the NIPOCS side surface of the polarizing plate and the liquid crystal surface of the selective reflection circularly polarizing film, respectively, and the transparent isothiate adhesive AD2
44 (manufactured by Special Color Materials Industry Co., Ltd.) were attached to each other.

The laminated film obtained as described above is
Size and angle (polarizer angle 45 degrees, diagonal 2
Punched to 93 mm). The punched laminated film was attached to a liquid crystal cell, and then autoclaved (5 atm, 70 ° C., 30 minutes). Next, an adhesive tape was attached to the end of the laminated film, and this was peeled off to remove the PET film remaining on the surface.

As described above, a bandpass filter composed of the liquid crystal composite layer of the selective reflection circularly polarizing film and the NIPOCS film could be formed. According to the bandpass filter of the present embodiment, the PET film has the surface protection function of the bandpass filter, and therefore, there is an advantage that it is not necessary to attach a surface protection film separately. The thickness of the laminated film attached to the liquid crystal cell was about 310 μm (including the thickness of the polarizing plate), and the thickness could be reduced by the thickness of the PET support substrate (75 μm).

Example 2 A band-pass filter layer was prepared by applying resin films having different refractive indexes to each other in a multilayer thin film. Specifically, a fluorine-based acrylate resin (LR202B manufactured by Nissan Chemical Co., Ltd.) as a low refractive index resin material.
And an inorganic high-refractive-index ultrafine particle-containing acrylate resin (JSR Desolite) are used as the high-refractive-index resin material, and these are used as a support substrate (Teijin PET film,
Twenty-one layers were laminated by a multi-layered thin film coating on a thickness of about 80 μm). The PET film of the supporting base material was not subjected to easy adhesion treatment or the like in consideration of peeling and removal later.

The fluorine-based acrylate resin had a refractive index of about 1.40, and the inorganic high refractive index ultrafine particle-containing acrylate resin had a refractive index of about 1.71. For the multilayer thin film coating, a microgravure coater was used, and after drying at 90 ° C. for 1 minute, UV polymerization (illuminance 50 mW / cm ² × 1)
The second coating film was repeatedly overcoated on the cured coating film. Since the bandpass filter layer obtained in this manner had insufficient uniformity of in-plane transmission spectral characteristics, it was decided to select and use a region having good characteristics in the relevant wavelength range.

As described above, with respect to the emission spectra of the three-wavelength cold cathode fluorescent lamps of 435 nm, 545 nm and 610 nm, the transmission wavelength range is 420 nm to 450 nm and 530 nm.
A bandpass filter layer having a thickness of 550 nm and a wavelength of 600 to 620 nm was produced. The total coating thickness is 4 μm
It was weak.

The optical film (band-pass filter layer + PET film) obtained as described above was used as the original plate of the polarizing plate to be attached to the backlight side of the liquid crystal cell.
It was adhered by an optical adhesive layer (Optelclave manufactured by Adell Co.) having a thickness of 2 μm. This was cut out into a size suitable for a liquid crystal display device and attached to a liquid crystal cell, and then the PET film which is a supporting base material was peeled and removed to form a bandpass filter.

It has been found that the light transmitted through the bandpass filter of this embodiment is collimated in the vicinity of the front of about ± 20 degrees with respect to the three wavelengths. Further, the increase in thickness due to the addition of the bandpass filter was about 6 μm, and it was possible to reduce the thickness by about 80 μm by peeling and removing the supporting base material.

Example 3 A cholesteric liquid crystal polymer was applied in a thin film on a supporting substrate made of a polyethylene terephthalate film having a thickness of 80 μm to form a bandpass filter layer, and films 1 and 2 were obtained.

More specifically, with respect to the emission spectra of the three-wavelength cold cathode fluorescent lamps of 435 nm, 545 nm, and 610 nm,
Selective reflection wavelength band is 440 nm to 490 nm, 550 to 550 nm
A selective reflection circularly polarizing film 1 which reflects right circularly polarized light at 600 nm and 615 to 700 nm was prepared. The coating thickness of the film 1, that is, the thickness of the bandpass filter layer was less than 5 μm.

A film 2 which uses a cholesteric liquid crystal polymer and is coated with three types of layers having different selective reflection central wavelengths to perform Grandjean alignment to reflect left circularly polarized light in the entire visible light range of 410 to 700 nm. It was created. This is a reflective circularly polarizing plate usually used for the purpose of improving brightness, and the coating thickness of the film 2, that is, the thickness of the bandpass filter layer was slightly less than 5 μm.

Films 1 and 2 obtained as described above
Was cut out in a size and an angle suitable for a predetermined liquid crystal display device.

The polarizing plate arranged on the backlight side of the liquid crystal cell to which the films 1 and 2 are adhered (the polarizing plate corresponds to the optical device in the present invention) has a quarter of a liquid crystal polymer on the surface. The thing which formed the wave plate was used. The quarter-wave plate made of the liquid crystal polymer has a thickness of 3 μm, and the adhesive layer between the polarizing plate and the quarter-wave plate has a thickness of 3 μm.
was μm. The film 1 is attached to the polarizing plate via an adhesive having a thickness of 2 μm, the supporting base material of the film 1 is peeled and removed, and then the film 2 is similarly laminated and adhered, and then the supporting base material of the film 2. A bandpass filter was formed by peeling and removing.

It has been found that the light transmitted through the bandpass filter of this embodiment is collimated in the vicinity of the front of about ± 15 degrees with respect to the three wavelengths. Further, it was found that the thickness increase due to the addition of the bandpass filter was about 20 μm, which greatly contributes to the thinning of the liquid crystal display device.

Example 4 The laminated film of Example 1 was
Since it was difficult to handle in a diagonal size of 20 inches corresponding to the size of a large liquid crystal panel, the thickness of the PET film was set to 175 μm, and the PET film was allowed to remain until the completion of attachment to the liquid crystal cell. The total thickness of the laminated film is a release film on the adhesive material side (a PET film having a thickness of 38 μm, and the surface on the side in contact with the adhesive material for adhering the laminated film to a liquid crystal cell is treated with silicon. ) Was about 540 μm, and bending and undulation due to the weight of the film were hard to occur, and handling was easy.

In this example, P as a supporting substrate was used.
An antistatic layer was formed on the back side of the ET film. Specifically, a thickness of 0.2 by using HP4 antistatic treatment material (sol-gel reaction material containing conductive fine particles) manufactured by Sumitomo Osaka Cement Co., Ltd.
When an antistatic layer having a surface resistance value of 5 × 10 ⁹ Ω was formed, the amount of electrification when the supporting substrate was peeled off was 1000 V or less. Danger prevention, dust adhesion prevention, liquid crystal cell destruction prevention, peripheral IC chips It was found that it is effective in preventing the destruction of kinds.

Comparative Example 1 A cholesteric liquid crystal polymer was applied in a thin film on a supporting substrate made of a cellulose triacetate film having a thickness of 80 μm to form a bandpass filter layer, and films 1 and 2 were obtained.

More specifically, with respect to the emission spectra of the three-wavelength cold cathode fluorescent lamps of 435 nm, 545 nm and 610 nm,
Selective reflection wavelength band is 440 nm to 490 nm, 540 to 540 nm
A selective reflection circularly polarizing film 1 which reflects right circularly polarized light at 600 nm and 615 to 700 nm was prepared. The coating thickness of the film 1, that is, the thickness of the bandpass filter layer was less than 5 μm.

A film 2 which uses a cholesteric liquid crystal polymer and is coated with three types of layers having different selective reflection central wavelengths to perform Grandjean alignment to reflect left circularly polarized light in the entire visible light range of 410 to 700 nm. It was created. This is a reflective circularly polarizing plate usually used for the purpose of improving brightness, and the coating thickness of the film 2, that is, the thickness of the bandpass filter layer was slightly less than 5 μm.

Light transmitted through a bandpass filter formed by adhering the films 1 and 2 with an adhesive material having a thickness of 25 μm is collimated in the vicinity of the front of about ± 15 degrees with respect to the three wavelengths. I found out that Further, a quarter-wave plate having a thickness of 50 μm was attached to the bandpass filter of this comparative example via an adhesive having a thickness of 25 μm. The total thickness of the backlight collimating optical film thus obtained was about 245 μm, which was found to be insufficient for thinning the liquid crystal display device.

In the Examples and Comparative Examples described above, the instantaneous wavelength metering system MCPD2000 manufactured by Otsuka Electronics Co., Ltd. was used for measuring the reflection wavelength band, and the Spectroscopic Ellipso M220 manufactured by JASCO Corporation was used for evaluating the thin film characteristics. , The spectrophotometer U4 manufactured by Hitachi, Ltd. is used to evaluate the spectral characteristics of transmission and reflection.
100 is used for evaluating the characteristics of the polarizing plate, which is manufactured by Murakami Color Co., Ltd.
3 for measuring the phase difference value, Oji Scientific Instrumen
The birefringence measuring device KOBRA21D manufactured by t company is used to measure the viewing angle characteristics (contrast, color tone, brightness) by ELDIM.
The Ez contrast manufactured by the company was used.

[0078]

According to the present invention, a supporting substrate having a bandpass filter layer formed thereon is attached to an optical device (polarizing plate, retardation plate, etc.) constituting a liquid crystal display device, and then the supporting substrate is formed. By peeling only the bandpass filter layer and transferring the bandpass filter layer to the optical device, a bandpass filter composed of the bandpass filter layer (without a supporting substrate) is formed. Therefore, the band-pass filter according to the present invention does not have a supporting base material like the conventional band-pass filter, and the thickness is increased, the optical characteristics are deteriorated, and the reliability is lowered due to the supporting base material. Can be prevented. Incidentally, the bandpass filter according to the present invention is premised on the peeling and removal of the supporting base material, so it is not necessary to consider the thickness of the supporting base material, and the surface smoothness and the thermal history during the surface treatment,
A thick supporting base material can be used in consideration of the influence of tension, vibration, and the like. Further, since it becomes possible to use a thick supporting base material, it is possible to enhance the handling property. Furthermore, in order to prevent malfunctions in an automatic laminating machine that can be used when laminating a supporting substrate having a bandpass filter layer formed on an optical device, the automatic laminating machine ensures that each film is individually processed. Since the thickness of the supporting base material can be given so as not to fall below the lower limit of the thickness that can be picked up, it is possible to reduce work mistakes during manufacturing of the liquid crystal display device, which in turn contributes to cost reduction by improving yield. It has an excellent effect that it is possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a method of manufacturing a bandpass filter according to an embodiment of the present invention.

FIG. 2 shows transmission spectral characteristics of the selective reflection circularly polarizing film according to Example 1 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Supporting base material 2 ... Bandpass filter layer 3 ... Optical device 10 ... Bandpass filter

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H048 BA04 BA43 BA47 BB02 BB03                       BB10                 2H049 BA05 BA06 BA42 BB66 BB67                       BC22                 2H091 FA01Z FA08Z FA10Z FA11Z                       FA14Z FA41Z FB02 FB06                       FC01 FD15 GA16 GA17 LA02                       LA08

Claims (9)

[Claims] 1. A bandpass filter comprising a bandpass filter layer for selectively transmitting light, wherein the bandpass filter layer formed on a supporting substrate is attached to an optical device constituting a liquid crystal display device. A band for a liquid crystal display device, which is formed by a sticking step of and a transfer step of peeling the supporting base material from the bandpass filter layer and transferring the bandpass filter layer to the optical device. Pass filter. 2. The bandpass filter for a liquid crystal display device according to claim 1, wherein the bandpass filter layer is formed by precisely coating a cholesteric liquid crystal on a supporting base material. 3. The liquid crystal according to claim 1, wherein the band-pass filter layer is formed by laminating a resin material having a different refractive index on a supporting substrate by precision thin film coating. Bandpass filter for display device. 4. The optical device which has undergone the attaching step is attached to a liquid crystal cell of the liquid crystal display device, and then the transferring step is performed to form the optical device. A bandpass filter for a liquid crystal display device according to item 1. 5. The bandpass filter for a liquid crystal display device according to claim 1, wherein the supporting base material is subjected to an antistatic treatment. 6. The liquid crystal display according to claim 5, wherein the antistatic treatment is performed by forming an antistatic layer having a surface resistance value of 10 ¹² Ω or less on the supporting base material. Bandpass filter for equipment. 7. A liquid crystal cell, to which the optical device having the bandpass filter layer according to claim 1 is attached, and a light source having an emission line spectrum, and light directed toward the liquid crystal cell. And a backlight for emitting light. 8. A method of manufacturing a bandpass filter for a liquid crystal display device, which comprises a bandpass filter layer for selectively transmitting light, wherein the bandpass filter layer formed on a supporting substrate is formed on the liquid crystal display device. And a transfer step of peeling the support base material from the bandpass filter layer and transferring the bandpass filter layer to the optical device. Manufacturing method of bandpass filter for liquid crystal display device. 9. The bandpass for a liquid crystal display device according to claim 8, wherein the transfer process is performed after the optical device that has undergone the attaching process is attached to a liquid crystal cell of the liquid crystal display device. Filter manufacturing method.