WO2012147726A1 - Liquid crystal dimmer element - Google Patents

Abstract

This liquid crystal dimmer element is provided with a light source, a liquid crystal element for controlling the polarization state of light from the light source, and a pair of polarizing plates. The light source is configured so that at least one maximum value occurs in the wavelength range of 400 nm to 490 nm in the light emission spectrum thereof. The pair of polarizing plates includes a first polarizing plate and a second polarizing plate. The pair of polarizing plates is composed of films exhibiting uniaxial optical anisotropy. At least one polarizing plate in the pair thereof has a wavelength region in which the extinction ratio is 100 or greater in the range ±25 nm from the maximum value in the light emission spectrum of the light source. At least one polarizing plate in the pair thereof is configured such that A ≥ 0.95B, where A is the maximum value of the extinction ratio in the wavelength range of 400 nm to 490 nm, and B is the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm.

Description

Liquid crystal light control device

The present invention relates to a liquid crystal light control device.
This application claims priority based on Japanese Patent Application No. 2011-097174 filed in Japan on April 25, 2011, the contents of which are incorporated herein by reference.

As one form of the liquid crystal light control device, a blue light emitting diode (LED) or a near ultraviolet light emitting diode (LED) is used as a backlight, and a phosphor is disposed in a portion corresponding to a color filter. . This phosphor-excited color conversion type liquid crystal light control device converts the wavelength of light emitted from a backlight with a phosphor and displays a desired color (RGB or the like). This liquid crystal light control device has the advantage of high light utilization efficiency because there is no loss due to light absorption and wavelength conversion is performed by a phosphor as compared with a color filter type.

In the phosphor-excited color conversion liquid crystal light control device, a polarizing plate is provided between the liquid crystal layer and the phosphor in order to selectively excite a desired phosphor (see, for example, Patent Document 1).

JP 2009-134275 A

However, when a blue or near-ultraviolet light source is used as the light source of the liquid crystal light control device, it is necessary to optimize the retardation value of the liquid crystal layer so that the transmittance is maximized in the corresponding wavelength region.
On the other hand, a polarizing plate using iodine, which is known as a general polarizing plate material, has a low dichroic ratio (contrast) because parallel transmittance decreases and orthogonal transmittance increases in a short wavelength region of 490 nm or less. To drop.

An aspect of the present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal light control device having a high transmittance and dichroic ratio in a short wavelength region of 490 nm or less.

A liquid crystal light control device according to one embodiment of the present invention includes a light source, a liquid crystal device that controls a polarization state of light from the light source, and a pair of polarizing plates, and the light source has a wavelength of 400 nm in an emission spectrum. Having at least one maximum value in a range of ˜490 nm, the pair of polarizing plates is formed of a uniaxial optically anisotropic film, and at least one of the pair of polarizing plates has a maximum value ± 25 nm of the emission spectrum of the light source. Having a wavelength region in which the extinction ratio value is 100 or more in the range of A, the maximum extinction ratio in the wavelength range of 400 nm to 490 nm is A, and the maximum extinction ratio in the wavelength range of 380 nm to 780 nm is B A ≧ 0.95B.
In the liquid crystal light control device according to one embodiment of the present invention, the light source, the first polarizing plate, the liquid crystal device, and the second polarizing plate may be provided in this order.

In the liquid crystal light control device according to one embodiment of the present invention, the liquid crystal device includes a substrate and a liquid crystal layer, the first polarizing plate is provided between the light source and the liquid crystal device, and the second polarizing plate is , And may be provided between the substrate and the liquid crystal layer.

The liquid crystal light control device according to one embodiment of the present invention further includes a phosphor that absorbs light transmitted through the liquid crystal device and emits light in a wavelength region different from the light emission wavelength region of the light source. A polarizing plate, the liquid crystal element, the second polarizing plate, and a phosphor may be provided in this order.

The liquid crystal light control device according to an aspect of the present invention further includes a phosphor that absorbs light transmitted through the liquid crystal device and emits light in a wavelength region different from the light emission wavelength region of the light source, and the first polarizing plate. May be provided between the light source and the liquid crystal element, and the second polarizing plate may be provided between the substrate and the liquid crystal layer.

In the liquid crystal light control device according to one aspect of the present invention, the liquid crystal device has an effective phase difference value that maximizes transmittance in a range of maximum wavelength ± 25 nm existing in a wavelength range of 400 nm to 490 nm of the light source. You may have.

In the liquid crystal light control device of one embodiment of the present invention, the pair of polarizing plates has an extinction ratio value of 100 or more in a maximum wavelength range of ± 25 nm existing in a wavelength range of 400 nm to 490 nm of the light source, and When the maximum extinction ratio in the wavelength range of 400 nm to 490 nm is A and the maximum extinction ratio in the wavelength range of 380 nm to 780 nm is B, A ≧ 0.95B, and at least one of the polarizing plates is The light source may have a peak region with an extinction ratio in the range of the maximum wavelength ± 25 nm.

In the liquid crystal light control device of one embodiment of the present invention, the pair of polarizing plates has an extinction ratio value of 100 or more in a maximum wavelength range of ± 25 nm existing in a wavelength range of 400 nm to 490 nm of the light source, and When the maximum value of the extinction ratio in the wavelength range of 400 nm to 490 nm is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, A ≧ 0.95B is shown, and the first polarizing plate and the first polarizing plate The two polarizing plates may have a peak region of an extinction ratio in the range of the maximum wavelength of the light source ± 25 nm.

The contrast value CR _z obtained from the following equations (1) to (3) may have a change rate of 5% or less with respect to the contrast value CR _y obtained from the following equations (4) to (6).

(In the formulas (1) to (6), T _p (λ) represents parallel transmittance (spectral transmittance measured by placing the first polarizing plate and the second polarizing plate in a parallel Nicol arrangement). _c (λ) represents orthogonal transmittance (spectral transmittance measured by placing the first polarizing plate and the second polarizing plate in a crossed Nicol arrangement), and Y (λ) represents a Y component of tristimulus values. (Λ) represents the Z component of tristimulus values.)

The liquid crystal light control device according to another aspect of the present invention includes a light source, a liquid crystal device that controls a polarization state of light from the light source, light that passes through the liquid crystal device as excitation light, and an emission wavelength of the light source. And a pair of polarizing plates sandwiching the liquid crystal element, and the light source has at least one maximum value in the wavelength range of 400 nm to 490 nm in the emission spectrum. The polarizing plate has a parallel transmittance of 30% or more and a contrast value CR _z obtained from the following formulas (1) to (3) of 100 or more.

(In formulas (1) to (3), T _p (λ) represents parallel transmittance (spectral transmittance measured by installing a pair of polarizing plates in a parallel Nicol arrangement), and T _c (λ) is Represents orthogonal transmittance (spectral transmittance measured by installing a pair of polarizing plates in a crossed Nicol arrangement). Z (λ) represents a Z component of tristimulus values.)

According to the aspect of the present invention, a liquid crystal light control device having a high transmittance and dichroic ratio in a short wavelength region of 490 nm or less can be obtained.

It is a schematic sectional drawing which shows the liquid crystal light control element of 1st Embodiment. Polarization transmittance in the polarizing plate transmission axis direction and polarizing transmittance in the polarizing plate absorption axis direction of a polarizing film made of benzopurpurin which is one of the dichroic dyes provided on one surface of the iodine polarizing plate and the polyethylene terephthalate film It is a graph which shows. It is a schematic sectional drawing which shows the liquid-crystal light control element of 2nd Embodiment. It is a schematic sectional drawing which shows the liquid-crystal light control element of 3rd Embodiment. It is a schematic sectional drawing which shows the liquid crystal light control element of 4th Embodiment. It is a schematic sectional drawing which shows the liquid crystal light control element of 5th Embodiment. It is a schematic sectional drawing which shows the liquid crystal light control element of 6th Embodiment.

(1) 1st Embodiment FIG. 1: is a schematic sectional drawing which shows the liquid-crystal light control element of 1st Embodiment.
The liquid crystal light control device 10 of the present embodiment is schematically configured by a liquid crystal panel 20 and a backlight 30 disposed on the surface 20b side opposite to the display screen 20a.

The liquid crystal panel 20 includes a first polarizing plate 21, a first substrate 22, a liquid crystal layer 23 sandwiched between a pair of transparent electrodes (not shown), a second substrate 24, and a second polarizing plate 25. These have a structure in which they are stacked in order from the backlight 30 side.
The liquid crystal layer 23 is sandwiched between the first polarizing plate 21 and the second polarizing plate 25.
The first polarizing plate 21 is provided between the backlight 30 and the liquid crystal layer 23.
The second polarizing plate 25 is provided on the surface opposite to the surface in contact with the liquid crystal layer 23 of the second substrate 24.
Note that the liquid crystal layer 23 includes a pixel electrode, a drive electrode, a thin film transistor (TFT), an alignment film, and the like, but illustration thereof is omitted here.

As the backlight 30, one having at least one maximum value in a wavelength range of 400 nm to 490 nm in the emission spectrum, that is, one having a maximum intensity in a wavelength range of 400 nm to 490 nm is used. Preferably, the backlight 30 having the maximum intensity in the wavelength range of 430 nm to 470 nm is used.
As the backlight 30, for example, a blue light emitting diode (blue LED) having a maximum value near a wavelength of 455 nm, a blue fluorescent tube having maximum values at wavelengths of 430 nm and 490 nm, or the like is used.

At least one of the first polarizing plate 21 and the second polarizing plate 25 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 30, and in the wavelength range of 400 nm to 490 nm. A dichroic dye polarizing plate satisfying the following formula (α), where A is the maximum extinction ratio and B is the maximum extinction ratio in the wavelength range of 380 nm to 780 nm.
A ≧ 0.95B (α)
Note that it is preferable that there is a wavelength region in which the extinction ratio value is 1000 or more in the range of the maximum value ± 25 nm of the backlight 30, and it is more preferable that there is a wavelength region in which the extinction ratio value is 10,000 or more.
In the above formula (α), the coefficient of B is 0.95, but preferably 0.97. If the coefficient of B is less than 0.95, the blue light usage efficiency is low, so that the display is low in brightness and contrast.

Here, the extinction ratio is expressed as performance inherent to each of the first polarizing plate 21 and the second polarizing plate 25 and is defined as follows.
Extinction ratio = (polarized light transmittance in the polarizing plate transmission axis direction) / (polarized light transmittance in the polarizing plate absorption axis direction)
Here, the polarization transmittance refers to the transmittance when ideal polarized light is incident using a Glan-Thompson prism.

Dichroic dyes include Acid red 266, Benzopurpurin, C.I. I. Direct Blue 67, Violet 20, Cyanine dye, Methyl Orange, Perylenebiscarboximides, RU 31.156, Sirius Super Brown RLL, AH 6556, and the like.

FIG. 2 shows the polarizing transmittance in the polarizing plate transmission axis direction and polarizing plate absorption axis direction of a polarizing film made of benzopurpurin which is one of the dichroic dyes provided on one surface of the iodine polarizing plate and the polyethylene terephthalate film. It is a graph which shows the polarized light transmittance of this.
In FIG. 2, the symbol a is the polarization transmittance in the polarizing plate transmission axis direction, the symbol b is the polarization transmittance in the polarizing plate absorption axis direction, the symbol c is the extinction ratio of this polarizing plate, and the symbol d is a blue light emitting diode (blue LED). The intensity of the light emitted from.

As shown in FIG. 2, the polarizing film made of Benzopurpurin has a maximum extinction ratio in the vicinity of a wavelength of 430 nm to 470 nm, and this maximum extinction ratio is substantially equal to the maximum emission value of the blue LED indicated by symbol d. Match. That is, the above formula (α) (A ≧ 0.95B) is satisfied.

As the 1st polarizing plate 21 and the 2nd polarizing plate 25, it is a uniaxial optical anisotropic film which consists of a coating-type polarizing film, a wire grid polarizing plate, etc., and the thing which does not require a support substrate is used.
As the uniaxial optical anisotropic film, a film having no restriction on the transmittance is used in the wavelength region other than the blue region. The uniaxial optically anisotropic film may be composed of a dichroic dye having almost no dichroic ratio (extinction ratio) in the light of the green to red region.

The uniaxial optically anisotropic film constituting the first polarizing plate 21 is prepared by dissolving a dichroic dye in various organic solvents to prepare a solution, and using a coating device such as a die coater, slit coater, bar coater, etc. It is formed by applying the solution on the surface opposite to the surface in contact with the liquid crystal layer 23 and drying it.
Similarly, the uniaxial optical anisotropic film forming the second polarizing plate 25 is prepared by dissolving a dichroic dye in various organic solvents to prepare a solution, and using a coating device such as a die coater, a slit coater, or a bar coater. The second substrate 24 is formed by applying the solution to the surface opposite to the surface in contact with the liquid crystal layer 23 and drying.
Examples of the method for orienting the dichroic dye include a method in which a solution in which the dichroic dye is dissolved is applied while applying a shearing force. According to this method, the direction in which the shearing force is applied, that is, the application direction of the solution becomes the transmission axis of the second polarizing plate 25, and the direction orthogonal to the direction in which the shearing force is applied is the absorption axis of the second polarizing plate 25. Become.

Further, as a method for aligning the dichroic dye, the surface of the second substrate 24 opposite to the surface in contact with the liquid crystal layer 23 is subjected to an alignment process such as rubbing, and the surface subjected to the alignment process is subjected to the alignment process. A method of orienting the dichroic dye by applying a solution in which the chromatic dye is dissolved is mentioned.
Furthermore, as a method for aligning the dichroic dye, an alignment film is formed on the surface of the second substrate 24 opposite to the surface in contact with the liquid crystal layer 23, and the alignment film is subjected to an alignment treatment such as rubbing. The method of orienting a dichroic dye is mentioned by apply | coating the solution which melt | dissolved the dichroic dye.
As described above, when the surface of the second substrate 24 opposite to the surface in contact with the liquid crystal layer 23 is subjected to the alignment treatment, and the solution in which the dichroic dye is dissolved is applied, the dichroic dye is aligned in the alignment treatment direction. Therefore, the absorption axis of the second polarizing plate 25 coincides with the alignment treatment direction.

As a method for aligning the dichroic dye, a photo-alignment film is formed on the surface opposite to the surface in contact with the liquid crystal layer 23 of the second substrate 24, and ultraviolet or A method of orienting a dichroic dye by irradiating polarized ultraviolet rays is mentioned.

Also, it is possible to adopt a structure in which the first polarizing plate 21 is installed on the side of the first substrate 22 in contact with the liquid crystal layer 23 by the same method as described above.

As the liquid crystal layer 23, it is preferable to use a liquid crystal layer having an effective retardation value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 30. In other words, the wavelength (WLC) at which the transmittance of the liquid crystal layer 23 is maximized and the wavelength (WBL) at which the backlight 30 exhibits the maximum intensity preferably satisfy the following relational expression (β). It is more preferable to satisfy the formula (γ).
WBL-25nm ≦ WLC ≦ WBL + 25nm (β)
WBL-25nm ≦ WLC ≦ WBL + 10nm (γ)

Here, the retardation value at which the liquid crystal layer 23 exhibits the maximum transmittance will be described.
The retardation value at which the liquid crystal layer 23 exhibits the maximum transmittance means that the birefringence (Δn) and the cell thickness (d) of the liquid crystal layer 23 need to be appropriately designed according to each display mode. This is not the Δnd obtained by the product of the birefringence index (Δn) of 23 and the cell thickness (d), but the effective value of Δnd obtained when the liquid crystal layer 23 is driven.
For example, the following design is required for the phase difference value (Δnd).
As a liquid crystal material used for the VA mode, for example, when a material showing Δn = 0.1 at a wavelength (λ) of 550 nm is used, the phase difference for obtaining the maximum transmittance of the liquid crystal layer 23 is 270 nm. However, since the liquid crystal molecules in the vicinity of the alignment film interface do not respond to an electric field, if the cell thickness (d) is simply set to 2.7 μm, the Δnd value is insufficient, so the cell thickness (d) is set to about 3.2 μm. It is common.

Also, the voltage-transmittance curve (VT curve) or gradation-luminance characteristic (gamma curve) of each RGB pixel is different for each color of the VA liquid crystal layer. This is because the refractive index of the liquid crystal molecules has wavelength dispersion. In order to match the RGB gamma characteristics, there is a case where no voltage is applied until the liquid crystal molecules are completely tilted. That is, the liquid crystal layer does not use the retardation value indicating the maximum transmittance, sets the maximum transmittance for each color in consideration of the RGB balance, and sets the effective Δnd value.

An example in which the liquid crystal material used in the VA mode in this embodiment is used is shown below.
In the liquid crystal layer 23, Δn increases at a wavelength (λ) of 455 nm and becomes approximately Δn = 0.11. Therefore, the cell thickness that satisfies the condition that the effective phase difference satisfies λ / 2 is VA mode liquid crystal. It is about 10% thinner than the layer.
Therefore, the cell thickness of 2.9 μm, which is about 10% thinner than the cell thickness of 3.2 μm designed for the wavelength of 550 nm, can be designed as the optimum value.
In this embodiment, Δnd needs to be taken into consideration only for the blue region. Therefore, it is possible to obtain the maximum transmittance by applying a voltage until the response of the liquid crystal molecules is saturated, thereby improving the light utilization efficiency. be able to.
On the other hand, setting the maximum transmittance at a voltage at which the response of the liquid crystal molecules does not saturate has the effect of increasing the response speed, and thus such a design is possible.

Also in the IPS mode, it is possible to appropriately design the effective Δnd in consideration of the fact that the liquid crystal molecules in the vicinity of the alignment film cannot be driven by an electric field and that the refractive index of the liquid crystal layer has wavelength dispersion. .
Similarly, a design that prioritizes transmittance or a design that prioritizes response speed is possible.

Further, similarly in the TN mode, the effective phase difference (Δn) of the liquid crystal layer at the backlight main wavelength and the optimum value of the cell thickness can be obtained, and the effective Δnd can be appropriately designed.

In the liquid crystal light adjusting device 10, the value of the contrast (CR _y ) obtained from the following formulas (4) to (6) in the value of the contrast (CR _z ) obtained from the following formulas (1) to (3). It is preferable that the change rate with respect to is 5% or less.

However, in the formulas (1) to (6), T _p (λ) represents the parallel transmittance (spectral transmittance measured by installing the first polarizing plate 21 and the second polarizing plate 25 in a parallel Nicol arrangement). T _c (λ) represents the orthogonal transmittance (spectral transmittance measured by placing the first polarizing plate 21 and the second polarizing plate 25 in a crossed Nicol arrangement). Y (λ) represents the Y component of the tristimulus value. Z (λ) represents a Z component of tristimulus values.

Thus, in the present embodiment, the contrast is defined as a value measured in the combination of the first polarizing plate 21 and the second polarizing plate 25.

Conventionally, the iodine polarizing plate that has been used has a characteristic that the transmittance is significantly reduced in a blue region, particularly in a region of a wavelength of 490 nm or less. Further, it is known that the light leakage when the first polarizing plate 21 and the second polarizing plate 25 are installed in a crossed Nicol arrangement becomes large in a wavelength region of 490 nm or less and the contrast is lowered. The maximum extinction ratio (or contrast) of the iodine polarizing plate appears around 600 nm to 650 nm.
In designing a liquid crystal light control device, the contrast and transmittance are generally optimally designed mainly in the region of 550 nm. Therefore, the contrast (CR _y ) obtained from the above equations (4) to (6). The value of was the most important.

Actually, when the contrast (CR _z ) value of the iodine polarizing plate is compared with the contrast (CR _y ) value, the contrast (CR _z ) value decreases by 10% or more compared to the contrast (CR _y ) value. I found out.
On the other hand, the first polarizing plate 21 and the second polarizing plate 25 in the present embodiment have increased transmittance in the blue region, and the extinction ratio (contrast) value has the maximum value in the blue region. The change rate of the contrast (CR _z ) value with respect to the _y ) value is as small as 1% or less, and the liquid crystal light control device 10 exhibits high contrast even in the blue region.

The liquid crystal light adjusting device 10 includes a first polarizing plate 21 provided between the backlight 30 and the liquid crystal layer 23, and a second substrate 24 provided on a surface opposite to the surface in contact with the liquid crystal layer 23 of the second substrate 24. A polarizing plate 25. At least one of the first polarizing plate 21 and the second polarizing plate 25 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 30, and in the wavelength range of 400 nm to 490 nm. When the maximum value of the extinction ratio is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, the uniaxial optical anisotropic film satisfies A ≧ 0.95B. According to this configuration, it is possible to increase the transmittance and increase the contrast in a short wavelength region with a wavelength of 490 nm or less. Further, since the liquid crystal layer 23 has an effective retardation value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 30, the light in the liquid crystal light control device 10 In addition, the process margin can be increased, such as a reduction in transmittance due to a change in cell thickness.

(2) Second Embodiment FIG. 3 is a schematic cross-sectional view showing a liquid crystal light control device of a second embodiment.
The liquid crystal dimming element 40 of this embodiment is schematically configured by a liquid crystal panel 50 and a backlight 60 disposed on the surface 50b side opposite to the display screen 50a.

The liquid crystal panel 50 includes a first polarizing plate 51, a first substrate 52, a liquid crystal layer 53 sandwiched between a pair of transparent electrodes (not shown), a protective film 54, a second polarizing plate 55, and a second substrate. 56, and these are laminated in order from the backlight 60 side.
The liquid crystal layer 53 is sandwiched between the first polarizing plate 51 and the second polarizing plate 55.
The first polarizing plate 51 is provided between the backlight 60 and the liquid crystal layer 53.
The second polarizing plate 55 is provided on the side of the second substrate 56 facing the liquid crystal layer 53.
A protective film 54 is provided between the liquid crystal layer 53 and the second polarizing plate 55. Therefore, from the viewpoint of reducing the thickness of the device and suppressing the influence of birefringence, the material of the protective film 54 is preferably a material capable of forming a thin film. In the case where the liquid crystal layer is formed in contact with the liquid crystal layer, it is preferable to select a material that can withstand the liquid crystal panel forming process. For example, a color filter flattening film, a thermosetting epoxy resin used as an overcoat film, a UV curable acrylic resin, or the like may be used. Alternatively, a fluorene resin having a cardo structure may be used. The material of the protective film 54 is not limited to these, and any material that satisfies the above requirements can be used.
When the protective film 54 is formed by application of an organic film, it can be formed with a thickness of 20 μm or less. Preferably, the thickness of the protective film 54 is 10 μm or less, more preferably 5 μm or less.
Further, the protective film 54 can be formed by applying an organic-inorganic hybrid overcoat material.
Furthermore, as the protective film 54, an inorganic film can be formed by sputtering or the like. Sputtered films such as a silicon nitride film and a silicon oxide film have high barrier properties and are suitable as a protective film. Since the inorganic sputtered film can be formed even with a thickness of 1 μm or less, it is more preferable from the viewpoint of thinning.
Note that the liquid crystal layer 53 includes a pixel electrode, a drive electrode, a thin film transistor (TFT), an alignment film, and the like, but illustration thereof is omitted here.

As the 1st polarizing plate 51, the thing similar to the above-mentioned 1st Embodiment is used.
As the 2nd polarizing plate 55, the thing similar to the above-mentioned 1st Embodiment is used.
As the liquid crystal layer 53, the same liquid crystal layer as that in the first embodiment is used.
As the backlight 60, the thing similar to the above-mentioned 1st Embodiment is used.

The liquid crystal light adjusting device 40 includes a first polarizing plate 51 provided between the backlight 60 and the liquid crystal layer 53, and a second polarizing plate 55 provided on the surface of the second substrate 56 facing the liquid crystal layer 53. . At least one of the first polarizing plate 51 and the second polarizing plate 55 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 60, and in the wavelength range of 400 nm to 490 nm. When the maximum value of the extinction ratio is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, the uniaxial optical anisotropic film satisfies A ≧ 0.95B. According to this configuration, it is possible to increase the transmittance and increase the contrast in a short wavelength region with a wavelength of 490 nm or less. Further, since the liquid crystal layer 53 has an effective retardation value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 60, the light in the liquid crystal light control device 40 In addition, the process margin can be increased, such as a reduction in transmittance due to a change in cell thickness.

(3) Third Embodiment FIG. 4 is a schematic cross-sectional view showing a liquid crystal light control device of a third embodiment.
The liquid crystal light adjusting device 70 of the present embodiment is schematically configured from a liquid crystal panel 80 and a backlight 90 disposed on the surface 80b side opposite to the display screen 80a.

The liquid crystal panel 80 includes a first substrate 81, a first polarizing plate 82, a first protective film 83, a liquid crystal layer 84 sandwiched between a pair of transparent electrodes (not shown), a second protective film 85, 2 polarizing plate 86 and the 2nd board | substrate 87 are comprised, and these have comprised the structure laminated | stacked in order from the backlight 90 side.
The liquid crystal layer 84 is sandwiched between the first polarizing plate 82 and the second polarizing plate 86.
The first polarizing plate 82 is provided on the side of the first substrate 81 that faces the liquid crystal layer 84.
The second polarizing plate 86 is provided on the side of the second substrate 87 facing the liquid crystal layer 84.
A first protective film 83 is provided between the liquid crystal layer 84 and the first polarizing plate 82.
A second protective film 85 is provided between the liquid crystal layer 84 and the second polarizing plate 86.
Note that the liquid crystal layer 84 includes a pixel electrode, a drive electrode, a thin film transistor (TFT), an alignment film, and the like, but illustration thereof is omitted here.

As the 1st polarizing plate 82, the thing similar to the above-mentioned 1st Embodiment is used.
As the 2nd polarizing plate 86, the thing similar to the above-mentioned 1st Embodiment is used.
As the liquid crystal layer 84, the same liquid crystal layer as that in the first embodiment is used.
As the 1st protective film 83 and the 2nd protective film 84, the thing similar to the above-mentioned 2nd Embodiment is used.
As the backlight 90, the thing similar to the above-mentioned 1st Embodiment is used.

According to the liquid crystal light adjusting device 70, the first polarizing plate 82 provided on the surface side facing the liquid crystal layer 84 of the first substrate 81 and the surface side facing the liquid crystal layer 84 of the second substrate 87 are provided. A second polarizing plate 86. At least one of the first polarizing plate 82 and the second polarizing plate 86 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 90, and in the wavelength range of 400 nm to 490 nm. When the maximum value of the extinction ratio is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, the uniaxial optical anisotropic film satisfies A ≧ 0.95B. With this configuration, it is possible to increase the transmittance and increase the contrast in a short wavelength region with a wavelength of 490 nm or less. Further, since the liquid crystal layer 84 has an effective phase difference value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 90, the light in the liquid crystal light control device 70. In addition, the process margin can be increased, such as a reduction in transmittance due to a change in cell thickness.

(4) Fourth Embodiment FIG. 5 is a schematic cross-sectional view showing a liquid crystal light control device of a fourth embodiment.
The liquid crystal light control device 100 of the present embodiment is schematically configured by a liquid crystal panel 110 and a backlight 120 disposed on the surface 110b side opposite to the display screen 110a.

The liquid crystal panel 110 includes a first polarizing plate 111, a first substrate 112, a liquid crystal layer 113 sandwiched between a pair of transparent electrodes (not shown), a second substrate 114, a second polarizing plate 115, a band pass. The filter 116, the phosphor layer 117, the third substrate 118, and the external light filter 119 are provided, and have a structure in which these are sequentially stacked from the backlight 120 side.
The liquid crystal layer 113 is sandwiched between the first polarizing plate 111 and the second polarizing plate 115.
The first polarizing plate 111 is provided between the backlight 120 and the liquid crystal layer 113.
The second polarizing plate 115 is provided on the surface opposite to the surface facing the liquid crystal layer 113 of the second substrate 114.
Note that the liquid crystal layer 113 includes a pixel electrode, a drive electrode, a thin film transistor (TFT), an alignment film, and the like, but illustration thereof is omitted here.

As the 1st polarizing plate 111, the thing similar to the above-mentioned 1st Embodiment is used.
As the 2nd polarizing plate 115, the thing similar to the above-mentioned 1st Embodiment is used.
As the liquid crystal layer 113, the same liquid crystal layer as that in the first embodiment is used.

As the backlight 120, the thing similar to the above-mentioned 1st Embodiment is used.
A linear film called a louver arranged in a blind shape may be arranged between the liquid crystal panel 110 and the backlight 120. The linear film collimates the light emitted from the backlight 120 and irradiates the liquid crystal panel 110 with the collimated light (parallel light). Alternatively, the light emitted from the backlight 120 is substantially collimated by the linear film, and the liquid crystal panel 110 is irradiated with the substantially collimated light (substantially parallel light).
As described above, a linear film arranged in a blind shape called a louver may be arranged between the liquid crystal panel 110 and the backlight 120 for the purpose of enhancing directivity. It is not limited to this.

The band-pass filter 116 has a structure such as a dielectric multilayer film, and the thickness of the band-pass filter 116 is set until the light transmitted through the second polarizing plate 115 enters the phosphor layer 117. It is preferable to set the degree of optical crosstalk that excites the phosphor placed in the adjacent pixel region. Specifically, the thickness of the band pass filter 116 is preferably smaller than the pixel interval.

The phosphor layer 117 includes a scatterer layer 117B, a red phosphor layer 117R, and a green phosphor layer 117G.

As the external light filter 119, a band-pass filter that transmits light in the visible light region and absorbs or reflects light in the blue to near ultraviolet region is used.

According to the liquid crystal light control device 100, the first polarizing plate 111 provided between the backlight 120 and the liquid crystal layer 113 and the surface opposite to the surface facing the liquid crystal layer 113 of the second substrate 114 are provided. A second polarizing plate 115. At least one of the first polarizing plate 111 and the second polarizing plate 115 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 120, and in the wavelength range of 400 nm to 490 nm. When the maximum value of the extinction ratio is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, the uniaxial optical anisotropic film satisfies A ≧ 0.95B. According to this configuration, it is possible to increase the transmittance and increase the contrast in a short wavelength region with a wavelength of 490 nm or less. Further, since the liquid crystal layer 113 has an effective retardation value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 120, the light in the liquid crystal light control device 100 In addition, the process margin can be increased, such as a reduction in transmittance due to a change in cell thickness.

In the present embodiment, the case where the phosphor layer 117 is the three primary colors composed of the scatterer layer 117B, the red phosphor layer 117R, and the green phosphor layer 117G is exemplified. It is not limited to. In the present embodiment, the phosphor layer may be of four primary colors or five primary colors, and a phosphor layer having a desired emission spectrum can be used.

(5) Fifth Embodiment FIG. 6 is a schematic cross-sectional view showing a liquid crystal light control device of a fifth embodiment.
The liquid crystal dimming element 130 of this embodiment is schematically configured by a liquid crystal panel 140 and a backlight 150 disposed on the surface 140b side opposite to the display screen 140a.

The liquid crystal panel 140 includes a first polarizing plate 141, a first substrate 142, a liquid crystal layer 143 sandwiched between a pair of transparent electrodes (not shown), a protective film 144, a second polarizing plate 145, and a bandpass filter. 146, the phosphor layer 147, the second substrate 148, and the external light filter 149, which are stacked in order from the backlight 150 side.
The liquid crystal layer 143 is sandwiched between the first polarizing plate 141 and the second polarizing plate 145.
The first polarizing plate 141 is provided between the backlight 150 and the liquid crystal layer 143.
The second polarizing plate 145 is provided on the side of the second substrate 148 facing the liquid crystal layer 143.
A protective film 144 is provided between the liquid crystal layer 143 and the second polarizing plate 145.
Note that the liquid crystal layer 143 includes a pixel electrode, a drive electrode, a thin film transistor (TFT), an alignment film, and the like, but illustration thereof is omitted here.

As the 1st polarizing plate 141, the thing similar to the above-mentioned 1st Embodiment is used.
As the 2nd polarizing plate 145, the thing similar to the above-mentioned 1st Embodiment is used.
As the liquid crystal layer 143, the same liquid crystal layer as that in the first embodiment is used.
As the protective film 144, the same film as in the second embodiment described above is used.

As the backlight 150, the thing similar to the above-mentioned 1st Embodiment is used.
Further, a linear film arranged in a blind shape called a louver may be disposed between the liquid crystal panel 140 and the backlight 150 as in the above-described fourth embodiment.
In addition, a linear film called a louver arranged in a blind shape may be arranged between the liquid crystal panel 140 and the backlight 150 for the purpose of improving directivity. It is not limited.

As the bandpass filter 146, the same one as in the above-described fourth embodiment is used.

The phosphor layer 147 includes a scatterer layer 147B, a red phosphor layer 147R, and a green phosphor layer 147G.

As the external light filter 149, the same filter as in the above-described fourth embodiment is used.

According to the liquid crystal light adjusting device 130, the first polarizing plate 141 provided between the backlight 150 and the liquid crystal layer 143 and the second polarizing plate provided on the surface facing the liquid crystal layer 143 of the second substrate 148. 145. At least one of the first polarizing plate 141 and the second polarizing plate 145 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 150, and in the wavelength range of 400 nm to 490 nm. When the maximum value of the extinction ratio is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, the uniaxial optical anisotropic film satisfies A ≧ 0.95B. According to this configuration, it is possible to increase the transmittance and increase the contrast in a short wavelength region with a wavelength of 490 nm or less. Further, since the liquid crystal layer 143 has an effective retardation value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 150, the light in the liquid crystal light control device 100 In addition, the process margin can be increased, such as a reduction in transmittance due to a change in cell thickness.

(6) Sixth Embodiment FIG. 7 is a schematic cross-sectional view showing a liquid crystal light control device of a sixth embodiment.
The liquid crystal dimming element 160 of this embodiment is schematically configured by a liquid crystal panel 170 and a backlight 190 disposed on the surface 170b side opposite to the display screen 170a.

The liquid crystal panel 170 includes a first substrate 171, a first polarizing plate 172, a first protective film 173, a liquid crystal layer 174 sandwiched between a pair of transparent electrodes (not shown), a second protective film 175, 2 polarizing plate 176, band pass filter 177, phosphor layer 178, second substrate 179, and external light filter 180, which are stacked in order from the backlight 190 side. Yes.
The liquid crystal layer 174 is sandwiched between the first polarizing plate 172 and the second polarizing plate 176.
The first polarizing plate 172 is provided on the side of the first substrate 171 facing the liquid crystal layer 174.
The second polarizing plate 176 is provided on the surface of the second substrate 179 that faces the liquid crystal layer 174.
A first protective film 173 is provided between the liquid crystal layer 174 and the first polarizing plate 172.
A second protective film 175 is provided between the liquid crystal layer 174 and the second polarizing plate 176.
Note that the liquid crystal layer 174 includes a pixel electrode, a drive electrode, a thin film transistor (TFT), an alignment film, and the like, but illustration thereof is omitted here.

As the 1st polarizing plate 172, the thing similar to the above-mentioned 1st Embodiment is used.
As the 2nd polarizing plate 176, the thing similar to the above-mentioned 1st Embodiment is used.
As the liquid crystal layer 174, the same liquid crystal layer as that in the first embodiment is used.
As the 1st protective film 173 and the 2nd protective film 175, the thing similar to the above-mentioned 2nd Embodiment is used.

As the backlight 190, the thing similar to the above-mentioned 1st Embodiment is used.
Further, a linear film arranged in a blind shape called a louver may be disposed between the liquid crystal panel 170 and the backlight 190 as in the fourth embodiment described above.
A linear film called a louver may be arranged between the liquid crystal panel 170 and the backlight 190 for the purpose of improving directivity. It is not limited.

As the bandpass filter 177, the same one as in the above-described fourth embodiment is used.

The phosphor layer 178 includes a scatterer layer 178B, a red phosphor layer 178R, and a green phosphor layer 178G.

As the external light filter 180, the same one as in the above-described fourth embodiment is used.

According to the liquid crystal light control device 160, the first polarizing plate 172 provided on the surface facing the liquid crystal layer 174 of the first substrate 171 and the surface facing the liquid crystal layer 174 of the second substrate 179 are provided. A second polarizing plate 176. At least one of the first polarizing plate 172 and the second polarizing plate 176 has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the backlight 190, and in the wavelength range of 400 nm to 490 nm. When the maximum value of the extinction ratio is A and the maximum value of the extinction ratio in the wavelength range of 380 nm to 780 nm is B, the uniaxial optical anisotropic film satisfies A ≧ 0.95B. According to this configuration, it is possible to increase the transmittance and increase the contrast in a short wavelength region with a wavelength of 490 nm or less. Further, since the liquid crystal layer 174 has an effective retardation value that maximizes the transmittance in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the backlight 190, the light in the liquid crystal light control device 160 In addition, the process margin can be increased, such as a reduction in transmittance due to a change in cell thickness.

The aspect of the present invention can be used in the field of liquid crystal light control devices.

10, 40, 70, 100, 130, 160... Liquid crystal light control elements 20, 50, 80, 110, 140, 170... Liquid crystal panels 21, 51, 82, 111, 141, 172. Polarizing plates 22, 52, 81, 112, 142, 171 ... first substrates 23, 53, 84, 113, 143, 174 ... liquid crystal layers 24, 56, 87, 114, 148, 179 ... first Two substrates 25, 55, 86, 115, 145, 176 ... second polarizing plates 30, 60, 90, 120, 150, 190 ... backlights 54, 144, ... protective films 83, 173, ... First protective film 85, 175, second protective film 116, 146, 177, band pass filter 117, 147, 178, phosphor layer 118, third substrate 119, 149, 180 ..External light fill

Claims (10)

A light source, a liquid crystal element that controls a polarization state of light from the light source, and a pair of polarizing plates,
The light source has at least one maximum value in a wavelength range of 400 nm to 490 nm in the emission spectrum,
The pair of polarizing plates includes a first polarizing plate and a second polarizing plate,
The pair of polarizing plates is composed of a uniaxial optically anisotropic film,
At least one of the pair of polarizing plates has a wavelength region in which the extinction ratio value is 100 or more in the range of the maximum value ± 25 nm of the emission spectrum of the light source,
At least one of the pair of polarizing plates satisfies A ≧ 0.95B, where A is the maximum extinction ratio in the wavelength range of 400 to 490 nm and B is the maximum extinction ratio in the wavelength range of 380 to 780 nm. Liquid crystal light control device. The liquid crystal light control device according to claim 1, wherein the light source, the first polarizing plate, the liquid crystal device, and the second polarizing plate are provided in this order. The liquid crystal element includes a substrate and a liquid crystal layer,
The first polarizing plate is provided between the light source and the liquid crystal element,
The liquid crystal light control device according to claim 1, wherein the second polarizing plate is provided between the substrate and the liquid crystal layer. Furthermore, it comprises a phosphor that absorbs light transmitted through the liquid crystal element and emits light in a wavelength range different from the emission wavelength range of the light source,
The liquid crystal light control device according to claim 1, wherein the light source, the first polarizing plate, the liquid crystal device, the second polarizing plate, and the phosphor are provided in this order. And a phosphor that absorbs light transmitted through the liquid crystal element and emits light in a wavelength range different from the emission wavelength range of the light source,
The first polarizing plate is provided between the light source and the liquid crystal element,
The liquid crystal light control device according to claim 1, wherein the second polarizing plate is provided between the substrate and the liquid crystal layer. 2. The liquid crystal light adjusting device according to claim 1, wherein the liquid crystal device has an effective retardation value having a maximum transmittance in a maximum wavelength range of ± 25 nm existing in an emission wavelength range of 400 nm to 490 nm of the light source. The pair of polarizing plates has an extinction ratio value of 100 or more in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the light source, and the maximum value of the extinction ratio in the wavelength range of 400 nm to 490 nm. Where A is 0.9 and B is the maximum extinction ratio in the wavelength range of 380 nm to 780 nm.
2. The liquid crystal light adjusting device according to claim 1, wherein at least one of the pair of polarizing plates has a peak region of an extinction ratio in a range of a maximum wavelength of ± 25 nm of the light source. The pair of polarizing plates has an extinction ratio value of 100 or more in the range of the maximum wavelength ± 25 nm existing in the wavelength range of 400 nm to 490 nm of the light source, and the maximum value of the extinction ratio in the wavelength range of 400 nm to 490 nm. Where A is 0.9 and B is the maximum extinction ratio in the wavelength range of 380 nm to 780 nm.
2. The liquid crystal light adjusting device according to claim 1, wherein the pair of polarizing plates has a peak region of an extinction ratio in a range of a maximum wavelength of ± 25 nm of the light source. The contrast value CR _z obtained from the following expressions (1) to (3) has a rate of change of 5% or less with respect to the contrast value CR _y obtained from the following expressions (4) to (6): Liquid crystal light control element.

(In the formulas (1) to (6), T _p (λ) represents parallel transmittance (spectral transmittance measured by placing the first polarizing plate and the second polarizing plate in a parallel Nicol arrangement). T _c (λ) represents orthogonal transmittance (spectral transmittance measured by placing the first polarizing plate and the second polarizing plate in a crossed Nicol arrangement), and Y (λ) is a Y component of tristimulus values. Z (λ) represents the Z component of tristimulus values.) A light source, a liquid crystal element that controls a polarization state of light from the light source, a phosphor that absorbs light transmitted through the liquid crystal element as excitation light, and generates light in a wavelength range different from the emission wavelength range of the light source, A pair of polarizing plates sandwiching the liquid crystal element,
The light source has at least one maximum value in a wavelength range of 400 nm to 490 nm in the emission spectrum,
At least one of the pair of polarizing plates is a liquid crystal light control device having a parallel transmittance of 30% or more and a contrast value CR _z obtained from the following formulas (1) to (3) of 100 or more.

(In the formulas (1) to (3), T _p (λ) represents parallel transmittance (spectral transmittance measured by placing the pair of polarizing plates in a parallel Nicol arrangement) T _c (λ) Represents orthogonal transmittance (spectral transmittance measured by placing the pair of polarizing plates in a crossed Nicol arrangement). Z (λ) represents a Z component of tristimulus values.)

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