JP2017026905A - Image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display capable of realizing both high luminance and excellent color reproducibility.SOLUTION: An image display comprises: a light-emitting device 100 including a light-emitting element 10 having an emission peak wavelength equal to or larger than 420 nm and equal to or smaller than 480 nm, a first phosphor 71 having a composition represented by formula (I): (where Mrepresents Ca, Ba, etc., 0.03≤x≤0.25, 0≤y<0.97, and x+y<1) and having an emission peak wavelength equal to or larger than 525 nm and equal to or smaller than 549 nm, and a second phosphor 72 having an emission peak wavelength equal to or larger than 600 nm and equal to or smaller than 680 nm; a color filter having red, green, and blue pixels; and a light transmission control member.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an image display device.

  In liquid crystal display devices used for many applications, it is required to improve characteristics such as high color reproduction and high luminance. These characteristics depend on the performance of the backlight light source, color filter, and the like. In recent years, a white light source including a blue light emitting LED and a yellow light emitting YAG phosphor has been used as a backlight light source.

  There is a color image display device using a backlight light source that is a combination of a blue or deep blue light emitting LED and a phosphor, and a color filter that applies a blue pixel that blocks an extra wavelength in a specific blue region. It is known that it is possible to realize a color image display device capable of obtaining high luminance even when a wide color reproduction range is designed (see, for example, Patent Document 1).

Also known is a semiconductor light emitting device comprising a semiconductor light emitting element, a green light emitting phosphor, and a red light emitting Mn ⁴⁺ activated phosphor having a narrow half-value width of the emission spectrum, and a display that displays a deeper red than before Can be realized (see, for example, Patent Document 2).

JP 2006-47975 A JP 2010-93132 A

However, in the color image display device described in Patent Document 1, a specific backlight light source and a color filter having a specific blue pixel must be combined, and depending on the combined color filter, a sufficient luminance and color reproduction range may be obtained. In some cases, it could not be obtained. Further, in the color image display device described in Patent Document 2, depending on the green light emitting phosphor to be combined, sufficient luminance may not be obtained when trying to achieve a wide color reproduction range.
In general, when a color filter is adjusted to achieve a high color reproduction range, there is a problem that most of the light emitted from the backlight light source is cut and the luminance is significantly reduced.

  An object of one embodiment of the present disclosure is to provide an image display device capable of achieving both high luminance and excellent color reproducibility.

Specific means for solving the above problems are as follows, and the present invention includes the following aspects.
A light emitting element having an emission peak wavelength in a range of 420 nm or more and 480 nm or less, and the following formula (I):
(Sr _1-xy , M ¹ _y , Eu _x ) Ga ₂ S ₄ (I)
(Wherein M ¹ represents at least one element selected from the group consisting of Be, Mg, Ca, Ba and Zn, and x and y are 0.03 ≦ x ≦ 0.25, 0 ≦ y. <0.97 and x + y <1.)
A first phosphor that emits light having an emission peak wavelength in a range of 525 nm to 549 nm when excited by light from the light emitting element, and excited by light from the light emitting element. A light emitting device including a second phosphor that emits light having an emission peak wavelength in a range of 600 nm to 680 nm;
A color filter having a red pixel, a green pixel and a blue pixel;
A light transmission control member;
The following formula (1):

(Wherein λ represents a wavelength (nm), I (λ) represents a relative light emission intensity of the first phosphor at a wavelength λnm, and T ^R (λ) represents a wavelength λnm of a red pixel of the color filter. This represents the relative spectral transmittance at.
Is less than 3.0 when the emission peak wavelength of the first phosphor is in the range of 525 nm or more and less than 540 nm, and the emission peak wavelength of the first phosphor is in the range of 540 nm or more and 549 nm or less. In the case of the image display device, the image display device is less than 5.5.

  According to an embodiment of the present disclosure, it is possible to provide an image display device that can achieve both high luminance and excellent color reproducibility.

It is a schematic sectional drawing which shows an example of the light-emitting device which concerns on this embodiment. It is an emission spectrum which shows the relative light emission intensity with respect to the wavelength of the light-emitting devices 1, 2 and C2. It is an enlarged view of the range of 480 nm or more and 630 nm or less of FIG. 2A. It is an emission spectrum which shows the relative light emission intensity with respect to the wavelength of the light-emitting devices 3, 4 and C1. It is an enlarged view of the range of 480 nm or more and 630 nm or less of FIG. 2C. It is a transmission spectrum which shows the relative transmittance | permeability with respect to the wavelength of the color filter used for the simulation of this embodiment. It is a simulation result of the emission spectrum emitted from the image display apparatus which concerns on Example 1, 2, and Comparative Example 2, and is a figure which shows the relative emitted light intensity with respect to a wavelength. FIG. 4B is an enlarged view of a range from 480 nm to 630 nm in FIG. 4A. It is a simulation result of the emission spectrum emitted from the image display apparatus which concerns on Example 3, 4 and the comparative example 1, and is a figure which shows the relative emitted light intensity with respect to a wavelength. FIG. 4C is an enlarged view of a range from 480 nm to 630 nm in FIG. 4C. It is a powder emission spectrum which shows the relative light emission intensity with respect to the wavelength of the green fluorescent substance 1, 2 and C2 which concern on this embodiment. It is a powder emission spectrum which shows the relative light emission intensity with respect to the wavelength of the green fluorescent substance 3, 4 which concerns on this embodiment, and C1.

Hereinafter, an image display device according to the present disclosure will be described based on the embodiments and examples. However, the embodiment described below exemplifies an image display device for embodying the technical idea of the present invention, and the present invention does not limit the image display device to the following. The relationship between the color name and the chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, and the like comply with JIS Z8110. Moreover, content of each component in a composition means the total amount of the said some substance which exists in a composition, unless there is particular notice, when the substance applicable to each component exists in a composition in multiple numbers.
The average particle size of the phosphor is a numerical value called a Fisher Sub Sieve Sizer's No., and is measured using an air permeation method.
The full width at half maximum of the phosphor means the wavelength width of the emission spectrum showing the emission intensity of 50% of the maximum emission intensity in the emission spectrum.

Image Display Device An image display device according to the present embodiment has a light emitting element having an emission peak wavelength in a range of 420 nm or more and 480 nm or less, and a composition represented by the following formula (I), and is used for light from the light emitting element A first phosphor that emits light having an emission peak wavelength in a range of 525 nm to 549 nm when excited and emits light having an emission peak wavelength in a range of 600 nm to 680 nm when excited by light from the light emitting element. A light emitting device including two phosphors, a color filter having a red pixel, a green pixel, and a blue pixel, and a light transmission control member, and an integrated value given by the following formula (1) is included in the light emitting device. When the emission peak wavelength of one phosphor is in the range of 525 nm or more and less than 540 nm, it is less than 3.0, and the emission peak wavelength of the first phosphor is 540 nm or more and 549 When it is in the range of nm or less, it is less than 5.5.

(Sr _1-xy , M ¹ _y , Eu _x ) Ga ₂ S ₄ (I)
In the formula (I), M ¹ represents at least one element selected from the group consisting of Be, Mg, Ca, Ba and Zn. x and y satisfy 0.03 ≦ x ≦ 0.25, 0 ≦ y <0.97, and x + y <1.

In the formula, λ represents the wavelength (nm), I (λ) represents the relative emission intensity at the wavelength λnm of the first phosphor, and T ^R (λ) represents the relative spectrum at the wavelength λnm of the red pixel of the color filter. Represents the transmittance.

In the formula (1), I (λ) is the relative emission intensity at the wavelength λ nm of the first phosphor, and means the emission intensity at the wavelength λ when the maximum emission intensity in the emission spectrum of the first phosphor is 1. . Here, the emission intensity of the first phosphor is obtained from the emission spectrum of the powder.
T ^R (λ) is the relative spectral transmittance at the wavelength λ nm of the red pixel of the color filter, and the spectral transmission at the wavelength λ when the maximum spectral transmittance in the spectral transmittance curve of the red pixel constituting the color filter is 1. Means rate.

  In the image display device of the present embodiment, the emission spectrum of the light emitting device and the transmission spectrum of the red pixel of the color filter have a specific relationship in the range of 560 nm to 730 nm. The integral value given by Equation (1) corresponds to the amount of light transmitted through the red pixel in the light emitted from the first phosphor, and takes a value in a specific range according to the emission spectrum of the first phosphor. The integral value given by the formula (1) is less than 3.0 when the emission peak wavelength of the first phosphor included in the light emitting device is in the range of 525 nm or more and less than 540 nm, and is 2.5 or less. preferable. The integral value is less than 5.5 and preferably 5.0 or less when the emission peak wavelength of the first phosphor is in the range of 540 nm to 549 nm.

  By combining a light emitting device having a specific configuration and a color filter having a specific spectral transmission characteristic so that the integral value given by Equation (1) becomes a predetermined value, high brightness and excellent color An image display apparatus that can achieve both reproducibility can be configured. This is considered as follows, for example. The first phosphor is a green light-emitting phosphor having a specific composition, and the amount of light in the range of 560 nm to 730 nm out of the light transmitted through the red pixel of the color filter among the light emitted from the first phosphor is a predetermined range. By adjusting the emission spectrum of the light-emitting device and the transmission spectrum of the color filter, the color separation between red and green is improved while maintaining high brightness. It is considered that the compatibility of light emission luminance can be achieved.

In the image display apparatus according to the present embodiment, the color reproduction range on the CIE1931 chromaticity diagram is preferably NTSC ratio 65% or more, more preferably 70% or more, and further preferably 75% or more.
The NTSC ratio is defined by the standard three primary colors defined by the National Television Standards Committee, the chromaticity (x, y) of the CIE 1931 XYZ color system, red (0.670, 0.330), green (0.210, 0.710), and blue (0.140, 0.080) as a reference, obtained by connecting the red, green, and blue monochromaticity of the image display device. It is the area ratio that compares the triangles. This area ratio is defined as the color reproduction range, and the higher the ratio, the better the color reproduction.

In the CIE1931 chromaticity diagram, the image display device according to the present embodiment has a color reproduction range of preferably 70% or more, more preferably 75% or more, and still more preferably 80% or more as the DCI coverage.
Note that the DCI standard is a digital cinema standard defined by an organization (Digital Cinema Initiative, LCC) created by seven movie studios in the United States.
In addition, the color gamut of the DCI standard includes blue coordinates (x, y) = (0.150, 0.060) and green coordinates (x, y) = (0. 0) in the xy chromaticity diagram of the CIE1931 XYZ color system. 265, 0.690) and a region indicated by a triangle connecting three points of red coordinates (x, y) = (0.680, 0.320). The DCI coverage means the area ratio of the color gamut of the DCI standard that overlaps the color gamut of the image display device to the area of the entire color gamut of the DCI standard.

  The image display apparatus according to the present embodiment has an integral value of the emission intensity of 570 nm to 600 nm with respect to the integral value of the emission intensity of 490 nm to 570 nm in the emission spectrum obtained by passing the light from the light emitting apparatus through the color filter. For example, the ratio is preferably less than 0.15 when the emission peak wavelength of the first phosphor is in the range of 525 nm to less than 540 nm, and preferably less than 0.22 in the range of 540 nm to 549 nm. Thereby, further excellent color reproducibility can be achieved.

Light-emitting device A light-emitting device that constitutes an image display device has a light-emitting element having an emission peak wavelength in a range of 420 nm or more and 480 nm or less, a composition represented by Formula (I), and is excited by light from the light-emitting element. A first phosphor that emits light having an emission peak wavelength in the range of 525 nm to 549 nm; a second phosphor that emits light having an emission peak wavelength in the range of 600 nm to 680 nm when excited by light from the light emitting element; including.

Light-Emitting Element The emission peak wavelength of the light-emitting element is in the range of 420 nm to 480 nm, and is preferably in the range of 445 nm to 455 nm from the viewpoint of light emission efficiency. By using a light emitting element having an emission peak wavelength in this range as an excitation light source, it is possible to configure a light emitting device that emits mixed light of light from the light emitting element and fluorescence from the phosphor. Furthermore, since light emitted from the light emitting element to the outside can be used effectively, loss of light emitted from the light emitting device can be reduced, and a highly efficient light emitting device can be obtained.

The half width of the emission spectrum of the light emitting element is not particularly limited. The half width can be set to 30 nm or less, for example.
It is preferable to use a semiconductor light emitting element such as an LED as the light emitting element. By using a semiconductor light emitting element as a light source, it is possible to obtain a stable light emitting device with high efficiency, high output linearity with respect to input, and strong against mechanical shock.
As a semiconductor light emitting element, for example, a blue color using a nitride semiconductor (In _X Al _Y Ga _1- XYN, where X and Y satisfy 0 ≦ X, 0 ≦ Y, and X + Y ≦ 1). A semiconductor light emitting element that emits green light or the like can be used.

The phosphor light emitting device has a composition represented by the formula (I), is excited by light from the light emitting element, and emits light having an emission peak wavelength in a range of 525 nm or more and 549 nm or less, and light emission And a second phosphor that emits light having an emission peak wavelength in a range of 600 nm to 680 nm when excited by light from the element. The first phosphor and the second phosphor (also simply referred to as “phosphor”) are included in, for example, a fluorescent member that covers the light emitting element to constitute a light emitting device.

  The fluorescent member can include, for example, a resin in addition to the phosphor. The resin is preferably a translucent resin, and examples thereof include thermosetting resins such as epoxy resins, silicone resins, epoxy-modified silicone resins, and modified silicone resins.

First phosphor In formula (I) representing the composition of the first phosphor, M ¹ represents at least one element selected from the group consisting of Be, Mg, Ca, Ba and Zn, and consists of Ca and Ba It is preferable to include at least one element selected from the group. x and y satisfy 0.03 ≦ x ≦ 0.25, 0 ≦ y <0.97, and x + y <1. From the viewpoint of light emission luminance, x is preferably 0.03 or more and 0.17 or less, and more preferably 0.11 or more and 0.14 or less. y is preferably 0 or more and 0.9 or less, and more preferably 0 or more and 0.8 or less.

The emission peak wavelength in the emission spectrum of the first phosphor is in the range of 525 nm to 549 nm. The maximum excitation wavelength of the first phosphor is preferably in the range of 430 nm to 470 nm, for example.
The emission peak wavelength of the first phosphor can be adjusted to a range of 525 nm or more and 549 nm or less by appropriately changing the composition represented by the formula (I).

The emission spectrum of the first phosphor has a single peak, a wavelength (W ^20% _L ) showing an emission intensity of 20% with respect to the maximum emission intensity in a range longer than the emission peak wavelength, and an emission peak wavelength. ^{(W max)} difference between the _^(W 20% ^{L -W max)} is for example 50nm or less, preferably 48 nm. Further, the difference (W ^20% _L −W ^max ) is 25 nm or more, preferably 35 nm or more.
If the wavelength showing 20% of the maximum emission intensity in the range shorter than the emission peak wavelength is W ^20% _S , the ratio of the wavelength difference between the long wavelength side and the short wavelength side (W ^20% _L − W ^max ) / (W ^max −W ^20% _S ) is preferably, for example, 1.3 or more and 1.5 or less.

  The average particle diameter of the first phosphor is not particularly limited and can be appropriately selected depending on the purpose and the like. The average particle size of the first phosphor is, for example, 1 μm to 30 μm, preferably 1 μm to 20 μm, and more preferably 3 μm to 20 μm.

  Content of the 1st fluorescent substance contained in a fluorescent member is not restrict | limited in particular, For example, they are 1 mass part or more and 20 mass parts or less with respect to 100 mass parts of resin which a fluorescent member contains, and 2 mass parts or more and 10 mass parts or less Is preferred.

Second phosphor The second phosphor is not particularly limited as long as it emits light having an emission peak wavelength in the range of 600 nm or more and 680 nm or less when excited by light from the light emitting element, and is appropriately selected from known phosphors. Can be used.
The emission peak wavelength in the emission spectrum of the second phosphor is in the range of 600 nm to 680 nm, preferably in the range of 610 nm to 670 nm, and more preferably in the range of 620 nm to 660 nm. The half width of the second phosphor is, for example, 30 nm or less, and preferably 10 nm or less. The half width of the second phosphor is, for example, 1 nm or more, and preferably 2 nm or more. The maximum excitation wavelength of the second phosphor is, for example, in the range of 430 nm to 470 nm, and preferably in the range of 440 nm to 460 nm.
When the emission peak wavelength of the second phosphor is in a specific range and the full width at half maximum is a specific value, more excellent color reproducibility can be achieved.

  The particle size and particle size distribution of the second phosphor are not particularly limited, and preferably have a single peak particle size distribution from the viewpoint of emission intensity and durability, and be a single peak particle size distribution with a narrow distribution width. Is more preferable. The average particle size of the second phosphor is, for example, 1 μm to 100 μm, preferably 5 μm to 70 μm, and more preferably 20 μm to 70 μm.

The second phosphor is selected from the group consisting of a phosphor having a composition represented by the following formula (IIa) and a phosphor having a composition represented by the following formula (IIb) from the viewpoint of emission luminance and color reproducibility It is preferable to contain at least one selected from the above.
3.5MgO.0.5MgF ₂ .GeO ₂ : Mn ⁴⁺ (IIa)
^{_{M 2 2 [M 1-a}} Mn 4+ a F 6] (IIb)

In the formula, M ² is at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is a Group 4 element and a Group 14 element At least one element selected from the group consisting of: a satisfies 0.01 <a <0.20.

Each of the second phosphors having the composition represented by the formula (IIa) or (IIb) is a phosphor activated with Mn ⁴⁺ and emits red light by absorbing light in the blue region.
In Formula (IIb), M ² is preferably selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and is at least one cation containing K ^+. , And a cation such as an alkali metal having K ⁺ as a main component. Here, “having K ⁺ as the main component” means that the content of K ⁺ in M ² in the formula (IIb) is 80 mol% or more, preferably 90 mol% or more, and 95 More preferably, it is at least mol%.

M in the formula (IIb) is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and M is titanium (Ti), zirconium (Zr), hafnium from the viewpoint of light emission characteristics. It is preferably at least one selected from the group consisting of (Hf), silicon (Si), germanium (Ge) and tin (Sn), and silicon (Si) or silicon (Si) and germanium (Ge) More preferably, silicon (Si), or silicon (Si) and germanium (Ge) are more preferable.
When M includes silicon (Si), or silicon (Si) and germanium (Ge), a part of at least one of Si and Ge includes a Group 4 element including Ti, Zr, and Hf, and C and Sn It may be substituted with at least one selected from the group consisting of Group 14 elements. In that case, the total content of Si and Ge in M is not particularly limited, and is preferably 90 mol% or more, and more preferably 95 mol% or more, for example.

  A in the formula (IIb) is 0.01 or more and 0.20 or less, preferably 0.015 or more and 0.15 or less, more preferably 0.02 or more and 0.10 or less, from the viewpoint of light emission efficiency and light emission intensity. More preferably, it is 0.03 or more and 0.10 or less.

The content of the second phosphor contained in the fluorescent member is not particularly limited, and is, for example, 80 parts by mass or more and 99 parts by mass or less, and 90 parts by mass or more and 98 parts by mass or less with respect to 100 parts by mass of the resin included in the fluorescent member. Is preferred.
Further, the ratio of the content of the second phosphor to the content of the first phosphor in the fluorescent member is not particularly limited, and is, for example, 4 or more and 99 or less, preferably 9 or more and 49 or less.

The fluorescent member may contain other phosphors other than the first phosphor and the second phosphor as necessary. Examples of other phosphors include (Sr _, Ca) AlSiN ₃ : Eu ²⁺ and SrLiAl ₃ N ₄ : Eu ²⁺ . When a fluorescent member contains other fluorescent substance, the content is 10 mass% or less with respect to the total amount of a 1st fluorescent substance and a 2nd fluorescent substance, for example, and 1 mass% or less is preferable.

  The method for producing the phosphor is not particularly limited, and can be appropriately selected from known means. For example, it can be manufactured as follows. A simple substance of an element, oxide, carbonate, nitride, chloride, fluoride, sulfide or the like contained in the phosphor composition is used as a raw material, and each of these raw materials is weighed so as to have a predetermined composition ratio. Further, an additive material such as a flux is appropriately added to the raw material, and mixed by a wet or dry method using a mixer. Thereby, it becomes possible to promote solid-phase reaction and form particles of uniform size. The mixer may be a ball mill that is usually used industrially, or a crusher such as a vibration mill, a roll mill, or a jet mill. The specific surface area can be increased by pulverization using a pulverizer. Moreover, in order to keep the specific surface area of the powder within a certain range, classification is performed using a wet type separator such as a sedimentation tank, a hydrocyclone, and a centrifugal separator, and a dry classifier such as a cyclone and an air separator. You can also The mixed raw materials are packed in a crucible made of SiC, quartz, alumina, BN, or the like, and fired in an inert atmosphere such as argon or nitrogen, a reducing atmosphere containing hydrogen, or an oxidizing atmosphere in the air. Firing is performed at a predetermined temperature and time. The fired product is pulverized, dispersed, filtered, etc. to obtain the desired phosphor powder. Solid-liquid separation can be performed by industrially used methods such as filtration, suction filtration, pressure filtration, centrifugation, and decantation. Drying can be performed by industrially used apparatuses such as a vacuum dryer, a hot-air heating dryer, a conical dryer, and a rotary evaporator.

  The fluorescent member may contain other components as needed in addition to the phosphor and the resin. Examples of other components include fillers such as silica, barium titanate, titanium oxide, and aluminum oxide, light stabilizers, and colorants. When a sealing member contains another component, the content in particular is not restrict | limited, According to the objective etc., it can select suitably. For example, when a filler is included as another component, the content thereof can be 0.01 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin.

  The form of the light emitting device is not particularly limited, and can be appropriately selected from commonly used forms. Examples of the light emitting device include a pin penetration type and a surface mounting type. In general, the pin through type refers to a type in which a light emitting device is fixed by penetrating leads (pins) of the light emitting device through through holes provided in a mounting substrate. The surface mount type refers to a type in which the lead of the light emitting device is fixed on the surface of the mounting substrate.

A light emitting device 100 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the light emitting device 100. The light emitting device 100 is an example of a surface mount type light emitting device.
The light emitting device 100 emits light on the short wavelength side of visible light (for example, a range of 380 nm to 485 nm), and emits light of a gallium nitride compound semiconductor having a light emission peak wavelength in a range of 430 nm to 470 nm. And a molded body 40 on which the element 10 is placed. The molded body 40 is formed by integrally molding the first lead 20 and the second lead 30 and a thermoplastic resin or a thermosetting resin. The molded body 40 has a recess having a bottom surface and side surfaces, and the light emitting element 10 is placed on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 20 and the second lead 30 through wires 60, respectively. The light emitting element 10 is covered with a fluorescent member 50. The fluorescent member 50 preferably includes a thermosetting resin such as an epoxy resin, a silicone resin, an epoxy-modified silicone resin, or a modified silicone resin. The fluorescent member 50 includes, for example, a first fluorescent body 71, a second fluorescent body 72, and a resin as a fluorescent body 70 that converts the wavelength of light from the light emitting element 10.

  The fluorescent member 50 is formed by being filled with a translucent resin, glass or the like so as to cover the light emitting element 10 placed in the recess of the molded body 40. Considering ease of production, the material constituting the fluorescent member is preferably a translucent resin. As the translucent resin, a silicone resin composition is preferably used, but an insulating resin composition such as an epoxy resin composition or an acrylic resin composition can also be used. The fluorescent member 50 contains the phosphor 70, but other materials can be added as appropriate. For example, by including a light diffusing material, the directivity from the light emitting element can be relaxed and the viewing angle can be increased.

  The fluorescent member 50 functions not only as a wavelength conversion member including the phosphor 70 but also as a member for protecting the light emitting element 10 and the phosphor 70 from the external environment. In FIG. 1, the phosphor 70 is unevenly distributed in the fluorescent member 50. Thus, by arranging the phosphor 70 close to the light emitting element 10, the wavelength of light from the light emitting element 10 can be efficiently converted, and a light emitting device having excellent light emission efficiency can be configured. The arrangement of the fluorescent member 50 including the phosphor 70 and the light emitting element 10 is not limited to the form in which they are arranged close to each other, and the fluorescent member is considered in consideration of the influence of heat on the phosphor 70. 50, the light emitting element 10 and the phosphor 70 may be spaced apart. In addition, by mixing the phosphor 70 with the entire fluorescent member 50 at a substantially uniform ratio, it is possible to obtain light in which color unevenness is further suppressed.

Color filter The color filter has at least a red pixel, a green pixel, and a blue pixel as colored pixels. The color pixel of the color filter is not particularly limited as long as the integral value given by the expression (1) falls within a predetermined range, and can be appropriately selected from commonly used color pixels. In particular, the colored pixels of the color filter preferably have the following configuration.

In the green pixel of the color filter, the ratio R ^G1 of the integral value in the wavelength range of 550 nm to 640 nm to the integral value in the wavelength range of 460 nm to 640 nm in the spectral transmission curve is preferably 25% or more, and 30% or more. More preferably. The upper limit value of the ratio ^RG1 is not particularly limited, but is, for example, 50% or less and 45% or less.

Furthermore the green pixels of the color filter is preferably a ratio ^{R G2} of the integrated value in the range of less than the wavelength 560 nm 640nm is 15% or more with respect to the integral value of the wavelength range of 460nm or more 640nm in the spectral transmission curve, at least 20% More preferably. The upper limit value of the ratio ^RG2 is not particularly limited, but is, for example, 40% or less and 35% or less.

The red pixel of the color filter preferably has a wavelength λ of ^{80% at} which the transmittance in a spectral transmission curve with a maximum transmittance of 100% is 80%, in a range of 615 nm or less, and more preferably in a range of 610 nm or less. preferable. The lower limit of the wavelength λ ^80% is, for example, 580 nm or more and 585 nm or more.
The red pixel preferably has a wavelength λ ^{50% at} which the transmittance in a spectral transmission curve with a maximum transmittance of 100% is 50%, in a range of 605 nm or less, and more preferably in a range of 600 nm or less. The lower limit value of the wavelength λ ^50% is, for example, 570 nm or more and 575 nm or more.

  The configuration of the color filter can be appropriately selected from conventionally known configurations. As a structure of a color filter, the well-known thing by which the colored layer which comprises a colored pixel is arrange | positioned on optically transparent board | substrates, such as glass, can be mentioned, for example.

The substrate used for the color filter may have a transmittance for visible light, and preferably has a transmittance of 80% or more. In general, it may be one used in an image display device, and examples thereof include a plastic substrate such as PET, a glass substrate, and the like, but a glass substrate is usually used. The thickness of the substrate is not particularly limited and may be appropriately selected depending on the purpose. The thickness of the substrate can be, for example, about 100 μm to 1 mm.
A light shielding pattern may be formed on the substrate. As the light shielding pattern, a pattern in which a metal thin film such as chromium or a light shielding resin composition is previously formed on a substrate by a known method may be used.

The colored pixels can be formed, for example, by forming a color filter resin composition layer in an opening other than the light-shielding pattern formed on a light-transmitting substrate and curing it.
The arrangement of the colored pixels is not particularly limited, and may be a general arrangement such as a stripe type, a mosaic type, a triangle type, or a four pixel arrangement type. Moreover, the width | variety, area, etc. of a coloring pixel can be set arbitrarily. The thickness of the colored pixel is usually in the range of 1 μm to 5 μm.

  Any method such as a known inkjet method, printing method, photoresist method, or etching method may be used as a method for manufacturing a colored pixel on the substrate. However, in consideration of high definition, controllability and reproducibility of spectral characteristics, the photoresist method is preferable. In the photoresist method, a colored composition in which a pigment is dispersed in an appropriate solvent together with a photoinitiator and a polymerizable monomer in a light-transmitting resin is applied on a transparent substrate, and a colored layer is formed by film formation. This colored layer is pattern-exposed and developed to form one color pixel, and these steps are repeated for each color to produce a color filter.

  When forming the colored layer which comprises the colored pixel of a color filter by a photoresist method, the following method is followed, for example. A pigment serving as a colorant is dispersed in a transparent resin, and then mixed with an appropriate solvent together with a photoinitiator and a polymerizable monomer. There are various methods such as a mill base, three rolls, and a jet mill as a method for dispersing the pigment as the colorant and the transparent resin, but the method is not particularly limited thereto.

  Specific examples of organic pigments that can be used for the colored composition forming the colored layer of the color filter are shown below by color index numbers. Examples of red pigments include C.I. I. Pigment Red (PR) 7, 9, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 97, 122, 123, 146, 149 168, 177, 178, 179, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 246, 254 255, 264, 272, 279 and the like.

  Examples of yellow pigments include C.I. I. In addition to Pigment Yellow (PY) 150, 138, PY 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 139, 144, 146, 147, 148, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 71,172,173,174,175,176,177,179,180,181,182,185,187,188,193,194,199,213,214, and the like.

  Examples of orange pigments include C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.

  Examples of green pigments include C.I. I. In addition to Pigment Green (PG) 36, PG 7, 10, 37, and the like can be given.

  Examples of blue pigments include C.I. I. Pigment Blue (PB) 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 80 and the like.

  Examples of purple pigments include C.I. I. Pigment Violet (PV) 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like.

  Said organic pigment may be used individually by 1 type according to the structure of the target colored layer, etc., or may be used in combination of 2 or more type.

  In combination with the organic pigment, an inorganic pigment may be used in combination in order to ensure good coatability, sensitivity, developability and the like while balancing saturation and lightness. Inorganic pigments include yellow lead, zinc yellow, red pepper (red iron oxide (III)), cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green, and other metal oxide powders, metal sulfide powders, metal powders, etc. Can be mentioned. Furthermore, you may contain dye in the range by which heat resistance does not fall for color matching.

  The resin used for the coloring composition is a light-transmitting resin having a transmittance of preferably 80% or more, more preferably 95% or more in the entire wavelength region of 400 nm to 700 nm in the visible light region. The resin includes a thermoplastic resin, a thermosetting resin, and a photosensitive resin. For the light-transmitting resin, if necessary, a precursor or a monomer or oligomer that forms a light-transmitting resin by being cured by radiation irradiation may be used alone or in combination of two or more. it can.

  For details of the resin, photoinitiator, polymerizable monomer, pixel forming method using these, and the like, reference can be made to, for example, the descriptions in paragraph numbers 0102 to 0119 of JP-A-2009-76836.

Light transmission control member The image display apparatus includes a light transmission control member. The light transmission control member controls light incident on the color filter by transmitting or non-transmitting light from the light emitting device according to an image to be displayed. The light transmission control member is appropriately selected from commonly used members. For example, a liquid crystal cell having a liquid crystal layer can be used.

  The image display device only needs to include a light emitting element with a specific configuration, a color filter with a specific configuration, and a light transmission control member, and the configuration is not particularly limited, and can be appropriately selected from the configurations of commonly used image display devices. it can.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

As the first phosphor, green phosphors 1 to 4 having the composition represented by the formula (I) are prepared by preparing a raw material mixture so as to have the composition shown below, and heat-treating the mixture. did.
Green phosphor 1: (Sr _0.68 , Ba _0.20 , Eu _0.12 ) Ga ₂ S ₄
Green phosphor 2: (Sr _0.88 , Eu _0.12 ) Ga ₂ S ₄
Green phosphor 3: (Sr _0.68 , Ca _0.20 , Eu _0.12 ) Ga ₂ S ₄
Green phosphor 4: (Sr _0.58 , Ca _0.30 , Eu _0.12 ) Ga ₂ S ₄

For comparison, green phosphors C1 and C2, which are β sialon phosphors having a composition represented by the following formula (III), were prepared.
_{Si 6-z Al z O z} N 8-z: Eu (III)
(0 <z ≦ 4.2)

The average particle diameter of the prepared phosphor, the chromaticity coordinates (x, y) of the emission color of the phosphor powder, the emission peak wavelength, and 20% of the maximum emission intensity in the range longer than the emission peak wavelength. Table 1 shows the difference (W ^20% _L −W ^max ) between the wavelength indicating the emission intensity (W ^20% _L ) and the emission peak wavelength (W ^max ).

Looking at W ^20% _L -W ^max corresponding to the emission intensity of the yellow region for each phosphor, the green phosphors 1 to 4 have smaller numerical values than the green phosphors C1 and C2 having different compositions, It can be seen that the emission intensity in the yellow region is small. Moreover, (W20 ^% _L- ^Wmax ) / ( ^Wmax- W20 ^% _S ) was 1.4.

As the second phosphor, a red phosphor 1 having a composition represented by the formula (IIa) was prepared.
^{_{K 2 [Si 1-a Mn}} 4+ a F 6] (IIa)
(0.01 <a <0.20)

(Production of light-emitting device 1)
A blue light emitting LED (light emitting element) having an emission wavelength of 451 nm was combined with the green phosphor 1 and the red phosphor 1 to produce a light emitting device as follows.
A phosphor blended so that the chromaticity coordinates of the mixed color light emitted from the light emitting device after passing through the color filter is approximately x = 0.285 and y = 0.265 is added to the silicone resin, mixed and dispersed, and then further removed. A phosphor-containing resin composition was obtained by foaming. Next, the phosphor-containing resin composition was poured and filled on the light emitting element, and further heated to cure the resin composition. The light emitting device 1 was manufactured through such steps.

(Production of light-emitting device 2)
A light emitting device 2 was produced in the same manner as described above except that the green phosphor 2 was used instead of the green phosphor 1.

(Production of light-emitting device 3)
A light emitting device 3 was produced in the same manner as described above except that the green phosphor 3 was used instead of the green phosphor 1.

(Production of light-emitting device 4)
A light emitting device 4 was produced in the same manner as described above except that the green phosphor 4 was used instead of the green phosphor 1.

(Production of light-emitting device C1)
A light emitting device C1 was produced in the same manner as described above except that the green phosphor C1 was used instead of the green phosphor 1.

(Production of light-emitting device C2)
A light emitting device C2 was produced in the same manner as described above except that the green phosphor C2 was used instead of the green phosphor 1.

  2A, 2B, 2C, and 2D show emission spectra showing the relative emission intensity with respect to the wavelengths of the light emitting devices 1 to 4, C1, and C2 obtained above. FIG. 2A is a light emission spectrum in the visible region showing the relative light emission intensity with respect to the wavelength for the light emitting devices 1, 2 and C2, and FIG. 2C is the visible region showing the relative light emission intensity with respect to the wavelength for the light emitting devices 3, 4 and C1. Is an emission spectrum. 2B is an enlarged view of a region from 480 nm to 630 nm in FIG. 2A, and FIG. 2D is an enlarged view of a region from 480 nm to 630 nm in FIG. 2C.

  FIG. 3 is a transmission spectrum (spectral transmission curve) showing the transmittance with respect to the wavelength of the color filter used in the image display apparatus. In the transmission spectrum shown in FIG. 3, the ratio of the integral value in the wavelength range of 550 nm to 640 nm to the integral value in the wavelength range of 460 nm to 640 nm is 40%. The ratio of the integral value in the wavelength range of 560 nm to 640 nm to the integral value in the wavelength range of 460 nm to 640 nm is 32%.

  In the transmission spectrum of the red pixel in FIG. 3, the wavelength at which the transmittance is 80% is 596 nm, and the wavelength at which the transmittance is 50% is 585 nm.

Example 1
The image display device 1 is configured by combining the light emitting device 1 obtained above and the color filter having the transmission spectrum shown in FIG.
About the image display apparatus 1, the spectrum of the transmitted light after transmitting the light from the light-emitting device 1 through the color filter which has the transmission spectrum shown in FIG. 3 was obtained by simulation. The obtained transmitted light spectrum is shown in FIG. 4A.

(Example 2)
The image display device 2 is configured using the light emitting device 2 instead of the light emitting device 1. FIG. 4A shows a transmitted light spectrum of the image display device 2 obtained in the same manner as in Example 1.

(Example 3)
The image display device 3 is configured using the light emitting device 3 instead of the light emitting device 1. FIG. 4C shows a transmitted light spectrum of the image display device 3 obtained in the same manner as in Example 1.

Example 4
The image display device 4 is configured using the light emitting device 4 instead of the light emitting device 1. FIG. 4C shows the transmitted light spectrum of the image display device 4 obtained in the same manner as in Example 1.

(Comparative Example 1)
The image display device C1 is configured using the light emitting device C1 instead of the light emitting device 1. FIG. 4C shows the transmitted light spectrum of the image display device C1 obtained in the same manner as in Example 1.

(Comparative Example 2)
An image display device C2 is configured using the light emitting device C2 instead of the light emitting device 1. FIG. 4A shows the transmitted light spectrum of the image display device C2 obtained in the same manner as in Example 1.

  4A is a visible region spectrum showing the relative emission intensity with respect to the wavelength of transmitted light for Examples 1 and 2 and Comparative Example 2, and FIG. 4C is the transmitted light spectrum for Examples 3 and 4 and Comparative Example 1. FIG. It is a spectrum of the visible region which shows the relative light emission intensity with respect to a wavelength. 4B is an enlarged view of a region from 480 nm to 630 nm in FIG. 4A, and FIG. 4D is an enlarged view of a region from 480 nm to 630 nm in FIG. 4C.

  With respect to the transmitted light spectrum shown in FIGS. 4A and 4C, the integral values given by the following formula (1) were calculated. The results are shown in Table 2.

In the formula, λ represents the wavelength (nm), I (λ) represents the relative emission intensity at the wavelength λnm of the first phosphor, and T ^R (λ) represents the relative spectrum at the wavelength λnm of the red pixel of the color filter. Represents the transmittance.

From Table 2, in Examples 1 and 2 and Comparative Example 2 in which the emission peak wavelength of the green phosphor is 525 nm or more and less than 540 nm, the integration is performed in Examples 1 and 2 in which the green phosphor has the composition represented by the formula (I). While the value is less than 2.5, in Comparative Example 2 in which the composition of the green phosphor is different, the integral value is 2.5 or more.
Further, in Examples 3 and 4 and Comparative Example 1 in which the emission peak wavelength of the green phosphor is 540 nm or more and 549 nm or less, in Examples 3 and 4 in which the green phosphor has a composition represented by the formula (I), the integral value is Whereas it is less than 5.5, in Comparative Example 1 in which the composition of the green phosphor is different, the integral value is 5.5 or more.

Table 3 shows the simulation result of the chromaticity coordinates of the transmitted light after the light from the light emitting device obtained above is transmitted through the color filter having the transmission spectrum shown in FIG. Table 3 shows the chromaticity coordinates CF ^R of the transmitted light from the red pixel of the color filter, the chromaticity coordinates CF ^G of the transmitted light from the green pixel, the chromaticity coordinates CF ^B of the transmitted light from the blue pixel, and the entire color filter It shows the chromaticity coordinates CF ^W of the transmitted light from. In addition, the luminance of the transmitted light after passing through the color filter is shown as relative luminance Y with the luminance in Comparative Example 1 as 100. Furthermore, NTSC ratio (%) and DCI inclusion rate (%) were calculated, respectively.
Also it was further calculates a ratio of the integral value ^{I Y} of 600nm or less of the light emission intensity above 570nm for the integral value ^{I G} of 490nm or 570nm or less of the light emission intensity in the emission spectrum after the color filter transmittance as the integral ratio ^I Y / ^{I G.}

As shown in Table 3, compared with Comparative Example 1, Examples 1 and 2 can significantly increase the NTSC ratio and DCI coverage while maintaining the relative luminance Y (≧ 97). Further, in Example 3, the relative luminance Y, the NTSC ratio, and the DCI inclusion rate can be increased as compared with Comparative Example 1. In Example 4, compared with Comparative Example 1, the NTSC ratio and the DCI coverage are substantially the same, but the relative luminance Y is high.
In Comparative Example 2, compared with Comparative Example 1, the NTSC ratio and DCI coverage are significantly higher, but the relative luminance is reduced. Further, as compared with Example 1 having the same emission peak wavelength (533 nm), the relative luminance, the NTSC ratio, and the DCI coverage are all low.

In general, when the emission peak wavelength of the green phosphor shifts to a short wave, the NTSC ratio and DCI coverage are increased, but the luminance is considered to be in a trade-off relationship.
As shown in FIG. 5A, the first phosphors (green phosphors 1 and 2) according to Examples 1 and 2 have a powder emission spectrum that is higher than that of the β sialon phosphor (green phosphor C2) of Comparative Example 1. As shown in FIG. 5B, the first phosphors (green phosphors 3 and 4) according to Examples 3 and 4 are those of Comparative Example 2 as shown in FIG. 5B. The β sialon phosphor (green phosphor C1) has a lower emission intensity in the wavelength region longer than the emission peak wavelength, that is, the yellow region in the emission spectrum of the powder, which is advantageous for NTSC ratio and DCI coverage. . This means that the yellow light emission component derived from the green phosphor after passing through the red pixel is less likely to be mixed with the light emission from the red phosphor, which means that the color purity of red is increased.
That is, since the thiogallate phosphor having the composition of the formula (I) having a longer peak wavelength than the β sialon phosphor has the same NTSC ratio and DCI coverage, high luminance can be obtained.

  The image display apparatus according to the present disclosure can simultaneously achieve excellent color reproducibility and high luminance, and has high industrial applicability.

10: light emitting element, 50: fluorescent member, 71: first phosphor, 72: second phosphor, 100: light emitting device

Claims (10)

A light emitting element having an emission peak wavelength in a range of 420 nm or more and 480 nm or less, and the following formula (I):
(Sr _1-xy , M ¹ _y , Eu _x ) Ga ₂ S ₄ (I)
(Wherein M ¹ represents at least one element selected from the group consisting of Be, Mg, Ca, Ba and Zn, and x and y are 0.03 ≦ x ≦ 0.25, 0 ≦ y. <0.97 and x + y <1.)
A first phosphor that emits light having an emission peak wavelength in a range of 525 nm to 549 nm when excited by light from the light emitting element, and excited by light from the light emitting element. A light emitting device including a second phosphor that emits light having an emission peak wavelength in a range of 600 nm to 680 nm;
A color filter having a red pixel, a green pixel and a blue pixel;
A light transmission control member;
With
Following formula (1):

(Wherein λ represents a wavelength (nm), I (λ) represents a relative light emission intensity of the first phosphor at a wavelength λnm, and T ^R (λ) represents a wavelength λnm of a red pixel of the color filter. This represents the relative spectral transmittance at.
Is less than 3.0 when the emission peak wavelength of the first phosphor is in the range of 525 nm or more and less than 540 nm, and the emission peak wavelength of the first phosphor is in the range of 540 nm or more and 549 nm or less. An image display device that is less than 5.5.   The image display device according to claim 1, wherein x is 0.11 or more and 0.14 or less.   The difference between the emission peak wavelength and the wavelength at which the first phosphor has an emission intensity of 20% with respect to the maximum emission intensity on the longer wavelength side than the emission peak wavelength in the emission spectrum is 50 nm or less. The image display device described in 1.   4. The image display device according to claim 1, wherein an average particle diameter of the first phosphor is 1 μm or more and 30 μm or less. 5.   5. The image display device according to claim 1, wherein the second phosphor has an emission peak wavelength of 610 nm or more and 670 nm or less and a half width of 30 nm or less. The second phosphor includes at least one selected from the group consisting of a phosphor having a composition represented by the following formula (IIa) and a phosphor having a composition represented by the following formula (IIb). The image display device according to any one of 1 to 5.
3.5MgO.0.5MgF ₂ .GeO ₂ : Mn ⁴⁺ (IIa)
^{_{M 2 2 [M 1-a}} Mn 4+ a F 6] (IIb)
(In the formula, M ² is at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is a Group 4 element and Group 14 This represents at least one element selected from the group consisting of elements, and a satisfies 0.01 <a <0.20.)   The green pixel of the color filter has a ratio of an integral value in a wavelength range of 550 nm or more and 640 nm or less to an integral value in a wavelength range of 460 nm or more and 640 nm or less in a spectral transmission curve of 25% or more. The image display device according to item.   The green pixel of the color filter has a ratio of an integral value in a wavelength range of 560 nm to 640 nm to an integral value in a wavelength range of 460 nm to 640 nm in a spectral transmission curve is 15% or more. The image display device described in 1.   The red pixel of the color filter has a wavelength with a transmittance of 80% in a spectral transmission curve in a range of 615 nm or less and a wavelength with a transmittance of 50% in a spectral transmission curve in a range of 605 nm or less. The image display device according to any one of 1 to 8.   In the emission spectrum obtained by passing the light from the light emitting device through the color filter, the ratio of the integrated value of the emission intensity of 570 nm to 600 nm to the integrated value of the emission intensity of 490 nm to 570 nm is the first fluorescence. The light emission peak wavelength of the body is less than 0.15 when it is in the range of 525 nm or more and less than 540 nm, and it is less than 0.22 when it is in the range of 540 nm or more and 549 nm or less. The image display device described.