KR102538377B1 - lighting devices and display devices - Google Patents

Abstract

A lighting device including an optical wavelength conversion sheet, an optical wavelength selection filter, and a light emitting element, wherein the light emitting element, the optical wavelength conversion sheet, and the optical wavelength selection filter are provided in this order, and the area of the optical wavelength selection filter is as described above. A lighting device characterized by being smaller than the area of the light wavelength conversion sheet and provided with the light emitting element spaced apart from the light wavelength conversion sheet. The problem that the color in the vicinity of the center portion of the lighting device is different from the color in the vicinity of the end portion of the lighting device is improved, and a lighting device with less color unevenness and a display device using the same are provided.

Description

lighting devices and display devices

The present invention relates to, for example, a lighting device used for a liquid crystal display or the like and a display device using the same.

In a lighting device used for a liquid crystal display or the like, a light emitting device such as a blue LED or a blue laser is used as a light source, and a film containing quantum dots or phosphors is used as a lighting device for expressing pure colors with high efficiency. A lighting device that performs adjustment is used (Patent Document 1).

In this lighting device, blue light is emitted from a light emitting element such as a blue LED or blue laser toward a film containing quantum dots or phosphors, and the emitted blue light is color-converted into green light or red light by the quantum dots or phosphors. Then, white light is obtained by synthesizing blue light from the light emitting element and green light and red light color-converted by quantum dots or phosphors.

Japanese Patent Publication No. 2013-544018

As described above, in the lighting device used for a liquid crystal display or the like, that is, in the lighting device for obtaining white light using a light emitting element such as a blue LED or blue laser and a film containing quantum dots or phosphors, the color near the center of the lighting device The effect of the light emission color of the light emitting element is stronger in the color near the end of the lighting device (the display color near the end of the screen in the case of a liquid crystal display) than (the display color near the center of the screen in the case of a liquid crystal display). If it is an LED or a blue laser, it becomes a bluish color).

An object of the present invention is to solve the problem that the color in the vicinity of the center portion of the lighting device is different from that in the vicinity of the end portion of the lighting device, and to provide a lighting device with less color unevenness and a display device using the same.

The above objects of the present invention have been basically achieved by the following inventions.

[1] an optical wavelength conversion sheet;

an optical wavelength selection filter;

light emitting element

It is a lighting device having a,

A light emitting element, a light wavelength conversion sheet, and a light wavelength selection filter are provided in this order,

an area of the optical wavelength selection filter is smaller than an area of the optical wavelength conversion sheet;

The lighting device characterized in that the light emitting element is provided to be spaced apart from the light wavelength conversion sheet.

[2] an optical wavelength conversion sheet;

an optical wavelength selection filter;

light emitting element

It is a lighting device having a,

A light emitting element, a light wavelength selection filter, and a light wavelength conversion sheet are provided in this order,

an area of the optical wavelength selection filter is smaller than an area of the optical wavelength conversion sheet;

The lighting device characterized in that the light emitting element is provided to be spaced apart from the light wavelength conversion sheet.

[3] a first light wavelength conversion sheet;

A second light wavelength conversion sheet;

light emitting element

It is a lighting device having a,

A first light wavelength conversion sheet, a light emitting element, and a second light wavelength conversion sheet are provided in this order,

The area of the first light wavelength conversion sheet is smaller than the area of the second light wavelength conversion sheet,

The lighting device characterized in that the light emitting element is provided to be spaced apart from the second light wavelength conversion sheet.

[4] The lighting device according to [1] or [2], wherein the light wavelength selection filter satisfies the following formula (1).

|λ2-λ3|≤50 (where λ1 <λ2, λ1 <λ3) (1)

λ1: Emission wavelength of the light emitting element (nm)

λ2: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 70%

λ3: Wavelength (nm) at which the transmittance of the optical wavelength selection filter is 30%.

[5] The lighting device according to any one of [1] to [3], wherein a surface of the light wavelength selection filter and/or the light wavelength conversion sheet has a concavo-convex shape.

[6] The lighting device according to [1] or [2], wherein a plurality of light emitting elements are provided corresponding to the entire surface of the light wavelength conversion sheet.

[7] The lighting device according to [3], wherein a plurality of light emitting elements are provided corresponding to the entire surface of the second light wavelength conversion sheet.

[8] The lighting device according to [1] or [2], characterized by further comprising a light guide plate arranged in an optical path of light emitted from the light emitting element from the light emitting element to the light wavelength conversion sheet.

[9] The lighting device according to [3], further comprising a light guide plate disposed in an optical path of light emitted from the light emitting element from the light emitting element to the second light wavelength conversion sheet.

[10] The lighting device according to [8] or [9], characterized in that a plurality of light emitting elements are provided along an edge of the light guide plate.

[11] It further comprises a luminance enhancing film, and furthermore, [1] to [characterized in that the luminance enhancing film is provided on the emitting side of any member of the light emitting element, the optical wavelength sheet, and the optical wavelength selection filter. 3] The lighting device according to any one of the above.

[12] Characterized in that the angle between the direction in which the transmittance of the optical wavelength selection filter at the wavelength λ3 is maximized and the direction in which the transmittance of the luminance enhancement film is maximized at the wavelength λ3 is 10° or less [ 11].

[13] Characterized in that the angle between the direction in which the transmittance of the optical wavelength selection filter at the wavelength λ3 is maximized and the direction in which the transmittance of the luminance enhancement film is maximized at the wavelength λ3 is 80° or more [ 11].

[14] Further comprising a regular reflective reflective film, further comprising providing the regular reflective reflective film on the opposite side of the emission side of any member of the light emitting element, optical wavelength sheet, and optical wavelength selection filter [ The lighting device according to any one of [1] to [3].

[15] A display device including a display panel and a lighting device installed adjacent to the display panel,

the lighting device,

A display device characterized by being the lighting device according to any one of [1] to [14].

According to the present invention, a lighting device with less color unevenness can be obtained, and when used for a display device, a display device with less color unevenness and excellent display performance can be obtained.

1 is a schematic diagram of an example of a lighting device.
2 is a schematic diagram of an example of a display device.
3 is a schematic diagram of the lighting device according to the first embodiment of the present invention.
4 is an example of the first wavelength and the second wavelength.
5 is an optical path when there is no optical wavelength selection filter in the first embodiment.
6 is an optical path in the case where there is an optical wavelength selection filter in the first embodiment.
7 is an example of the optical wavelength selection filter and the optical wavelength conversion sheet in the first embodiment.
8 is a schematic diagram of a lighting device according to a second embodiment of the present invention.
9 is a schematic diagram of a lighting device according to a third embodiment of the present invention.
Fig. 10 is an optical path when there is no optical wavelength selection filter in the third embodiment.
Fig. 11 is an optical path in the case where there is an optical wavelength selection filter in the third embodiment.
12 is an example of the optical wavelength selection filter and the optical wavelength conversion sheet in the third embodiment.
13 is a schematic diagram of a lighting device according to a fourth embodiment of the present invention.
14 is a schematic diagram of a lighting device according to a fifth embodiment of the present invention.
15 : is an optical path in case there is no 1st light wavelength conversion sheet in 5th Embodiment.
16 : is an optical path in case there exists a 1st light wavelength conversion sheet in 5th Embodiment.
17 is an example of the first light wavelength conversion sheet and the reflector in the fifth embodiment.
18 is a schematic diagram of a lighting device according to a sixth embodiment of the present invention.
19 is a simplified diagram of the lighting device A.
20 is an xy chromaticity diagram.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

Fig. 1 (a) is a schematic cross-sectional view of an example of the lighting device of the present invention, and Fig. 1 (b) is a schematic plan view of a substrate, an LED, and a reflector. 2 is a schematic sectional view in the case of using a liquid crystal display as a display device, for example. Examples of liquid crystal displays include, but are not limited to, TVs, monitors, notebook-type personal computers, tablet-type portable terminals, and smartphones. In addition, the lighting device can be suitably used as various lighting devices such as home lighting equipment and facility lighting equipment, in addition to being usable for display devices such as signboards and vending machines other than liquid crystal displays, but is not limited thereto. . As the optical film of FIGS. 1 and 2 , a diffusion film, a prism film, a retroreflective film, and the like are used.

A light wavelength conversion sheet is a sheet which converts light of a specific wavelength into light of another wavelength. In the present invention, a light wavelength conversion sheet that converts light of a specific wavelength (light of the first wavelength) into light of another wavelength (light of the second wavelength) is preferably used.

Here, converting light of a specific wavelength into light of another wavelength means that light having a peak at a specific wavelength (light of the first wavelength) is converted into light having a peak at a wavelength other than the specific wavelength (light of the second wavelength). means to convert In addition, the light of the second wavelength may be light having a peak at one wavelength or light having a peak at each of two wavelengths. That is, the light of the first wavelength may be converted into light of the second wavelength having a peak at one wavelength (second wavelength) having a different peak wavelength from the light of the first wavelength by the light wavelength conversion sheet, It may be converted into two types of light: light having a peak at two wavelengths α and light having a peak at the second wavelength β.

The light of the first wavelength is preferably light of a wavelength having a peak at 200 nm or more and less than 380 nm (near ultraviolet) and/or light of a wavelength having a peak at 380 nm or more and less than 495 nm (blue). More preferably, it is light of a wavelength having a peak at 220 nm or more and 350 nm or less and/or light at a wavelength having a peak at 400 nm or more and 470 nm or less, and even more preferably light at a wavelength having a peak at 240 nm or more and 320 nm or less and/or 410 nm It is light of a wavelength having a peak of 460 nm or less. As a light emitting element which emits light of these wavelengths, a near-ultraviolet LED and a blue LED are mentioned, for example. In addition, as light of the second wavelength, light having a peak at 495 nm or more and less than 570 nm (green), light having a peak at 570 nm or more and less than 590 nm (yellow), and light having a peak at 590 nm or more and 750 nm or less (red) It is preferable that it is light of at least one wavelength selected from the group which consists of light of a wavelength. More preferably, at least one wavelength selected from the group consisting of light having a peak at 510 nm or more and 565 nm or less, light having a peak at 575 nm or more and 590 nm or less, and light having a peak at 600 nm or more and 700 nm or less. light, more preferably, at least one selected from the group consisting of light having a peak at 520 nm or more and 555 nm or less, light having a peak at 580 nm or more and 590 nm or less, and light having a peak at 610 nm or more and 680 nm or less. It is a single wavelength of light.

Further, the light wavelength selection filter is a filter that transmits or reflects light of a specific wavelength.

Here, the area of the light wavelength selection filter is preferably smaller than the area of the light wavelength conversion sheet. It is preferable to make the area of the light wavelength selection filter smaller than the area of the light wavelength conversion sheet and partially arrange it in the lighting device because the color of the light emitted from the lighting device can be partially adjusted efficiently.

In addition, a light emitting element refers to a semiconductor element that emits light. Although the light emitting element may be installed in any way in the lighting device, for example, when it is installed on a substrate, it is preferable that a plurality of light emitting elements are provided corresponding to the entire surface of the light wavelength conversion sheet in terms of efficiently emitting light, and will be described later. In the case of using a light guide plate, it is preferable from the viewpoint of luminous efficiency that a plurality of light guide plates are provided along the edge of the light guide plate.

(First Embodiment)

The first embodiment, which is an example of the lighting device of the present invention, will be described using FIGS. 3 to 7 .

3 is a schematic diagram of the lighting device according to the first embodiment of the present invention. A light wavelength conversion sheet 31 and a light wavelength selection filter 32 are provided, and a blue LED 33 is provided on a substrate 34 as a light emitting element. Further, in order to reflect and diffuse the light from the light emitting element, a reflector 37 and a diffuser plate 38 are provided.

The blue LED 33, the light wavelength conversion sheet 31, and the light wavelength selection filter 32 are provided in this order.

The blue LED 33 is provided at a distance from the light wavelength conversion sheet 31 and emits light toward the light wavelength conversion sheet 31 .

The area of the light wavelength selection filter 32 is preferably smaller than the area of the light wavelength conversion sheet 31 . It is preferable to make the area of the light wavelength selection filter 32 smaller than the area of the light wavelength conversion sheet 31 and partially arrange it in the lighting device because the color of the light emitted from the lighting device can be partially adjusted efficiently.

In the first embodiment, the light wavelength selection filter 32 reflects light of a first wavelength emitted from the blue LED 33, and the light of the first wavelength is converted by the light wavelength conversion sheet 31, Light of the second wavelength generated is transmitted.

The optical wavelength selection filter 32 in the first embodiment has a peak wavelength for light of the second wavelength converted by the optical wavelength conversion sheet 31 (hereinafter referred to as the peak wavelength of the second wavelength). A filter that transmits 85% or more of the light of the first wavelength and reflects 20% or more of the light of the peak wavelength (hereinafter sometimes referred to as the peak wavelength of the first wavelength) with respect to the light of the first wavelength. says That is, a filter having a transmittance of 85% or more at the peak wavelength of the second wavelength and a reflectance of 20% or more at the peak wavelength of the first wavelength. In addition, when there are two or more lights of the second wavelength, a filter having a transmittance of 85% or more with respect to all the lights of the second wavelength is referred to.

The light of the first wavelength is light having a peak at a specific wavelength, and the light of the second wavelength is light having a peak at a wavelength different from that of the light of the first wavelength.

4 is an example of the first wavelength and the second wavelength. In the example of the wavelength of FIG. 2, the light emitting element is a blue LED, and the light wavelength conversion sheet converts blue light of a blue wavelength, which is a first wavelength, emitted from the blue LED to emit green light of a green wavelength, which is a second wavelength. Quantum dots for green This is an example of a case in which two types of quantum dots are contained: and quantum dots for red that emit red light of a red wavelength that is a second wavelength by converting blue light. The peak of blue light of the blue LED is 450 nm, the peak of green light is 550 nm, and the peak of red light is 610 nm. By synthesizing these lights, white light is obtained.

5 and 6 are diagrams showing the optical path when there is no light wavelength selection filter 32 and when there is, respectively.

As shown in Fig. 6, the light wavelength selection filter 32 transmits the green light and red light converted by the light wavelength conversion sheet, and reflects part or all of the blue light emitted by the blue LED. Here, the fact that a part of the blue light emitted by the blue LED is reflected means that the reflectance at the peak wavelength of the blue light emitted by the blue LED is 20% or more, and all of the blue light emitted by the blue LED is reflected. It means that the reflectance in the peak wavelength of the blue light emitted by the blue LED is 100% or more.

Therefore, the blueness of the light emitted to the emission surface side of the light wavelength selection filter 32 is lower than that of the light emitted to the emission surface side in the case of FIG. 5, that is, when there is no optical wavelength selection filter 32.

According to this principle, color unevenness of the lighting device is improved by partially arranging the light wavelength selection filter 32 in a portion having high blueness (a portion where the effect of the light emission color of the light emitting element is strong), such as near the end of the lighting device. can do.

In addition, since the blue light reflected by the light wavelength selection filter 32 is reused in the lighting device by being reflected by a reflector or the like, light loss is small. Therefore, compared to other color control methods that reduce blueness by absorbing blue light, color control can be performed with less light loss.

It is preferable that the light wavelength selection filter 32 has a reflectance of 20% or more at the peak wavelength of the first wavelength. On the other hand, if the reflectance is too high, the effect of reducing the blueness becomes too large, resulting in color unevenness in some cases. Therefore, the reflectance of the peak wavelength of the first wavelength is more preferably 25 to 90%, still more preferably 30%. to 80%.

The transmittance of the light wavelength selection filter 32 at the peak wavelength of the second wavelength is preferably 85% or more, more preferably 87% or more, and still more preferably 90% or more.

The light wavelength selection filter 32 may be laminated on the light wavelength conversion sheet 31 as shown in FIG. 7 , for example.

The light wavelength selection filter 32 also preferably satisfies the following formula (1). Equation (1) below shows that the change in transmittance between the wavelength range for reflecting light and the wavelength range for transmitting light is steep, and as |λ2-λ3| becomes smaller, the change occurs more steeply from the wavelength band for reflection to the wavelength range for transmission. do. In this way, blue light is converted in the light wavelength conversion sheet from the wavelength band that transmits from the reflected wavelength band, that is, the wavelength band that reflects the blue light emitted by the blue LED as described in the first embodiment, and transmits green light of a green wavelength that is the second emission wavelength. By rapidly changing the wavelength band, it is possible to transmit green light while selectively and efficiently reflecting only blue light, making it easy to obtain the maximum effect of the light wavelength selection filter.

|λ2-λ3|≤50 (where λ1<λ2, λ1<λ3) (1)

λ1: Emission wavelength of the light emitting element (nm)

λ2: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 70%

λ3: Wavelength (nm) at which the transmittance of the optical wavelength selection filter is 30%.

As the optical wavelength selection filter, a laminate of two types of films having different refractive indices that are transparent in the visible light region is preferably used. By laminating two types of films having different refractive indices, light is reflected at the interface between the films, and the wavelength of reflected light can be selected by adjusting the difference in refractive index between the two types of films and the thickness of each film. In addition, the reflectance can be adjusted by adjusting the number of stacked layers of the two types of films alternately stacked.

The two types of films may be organic resin materials or inorganic materials, and the organic resin may be either a thermoplastic resin or a curable resin. Moreover, a blend of a homoresin, copolymer resin, or two or more types of resin may be sufficient. More preferably, since it has good moldability, it is a thermoplastic resin. In addition, in each resin, various additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducing agents, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, dope agents for adjusting the refractive index, etc. are added. it may be

In the case of using a blue LED, it is also preferable to include an optical whitening agent in a light wavelength selection filter. The fluorescent whitening agent is excited by light with a shorter wavelength than the light emission wavelength of the blue LED and emits blue light. By including the fluorescent whitening agent, the light emitted from the LED but with a short wavelength that cannot be converted by the light wavelength conversion sheet can be converted to an optical wavelength. It can be converted into blue light that can be converted into green light or red light with the conversion sheet, and it becomes possible to improve the luminance when used as a lighting device.

Examples of the thermoplastic resin include polyolefin resins such as polyethylene, polypropylene, polystyrene, and polymethylpentene, alicyclic polyolefin resins, polyamide resins such as nylon 6 and nylon 66, aramid resins, polyethylene terephthalate, polybutylene terephthalate, and polybutylene terephthalate. Polyester resins such as propylene terephthalate, polybutyl succinate, polyethylene-2,6-naphthalate, polycarbonate resins, polyarylate resins, polyacetal resins, polyphenylene sulfide resins, tetrafluoroethylene resins, 3 Fluoroethylene resin, trifluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer, fluororesin such as vinylidene fluoride resin, acrylic resin such as PMMA, methacrylic resin, polyacetal resin, polyglycolic acid resin, polylactic acid A resin, an acrylonitrile/butadiene styrene copolymer, an acrylonitrile/ethylene/propylene rubber, a styrene copolymer or the like can be used. Among these, from the viewpoints of strength, heat resistance and transparency, a polyester resin is particularly preferred.

Among the polyester resins, polyethylene terephthalate and copolymers thereof, polyethylene naphthalate and copolymers thereof, polybutylene terephthalate and copolymers thereof, polybutylene naphthalate and copolymers thereof, and further polyhexamethylene terephthalate and copolymers thereof , polyhexamethylene naphthalate, copolymers thereof, and the like are preferably used.

In order to obtain a light wavelength selection filter satisfying the above expression (1), it is also preferable to use a laminated film containing a thermoplastic resin. In this case, the number of layers tends to increase, but by controlling the thickness of a large number of layers, it is also easy to steepen the change in the wavelength band or especially from the reflecting wavelength band to the transmitting wavelength band.

The shape of the light wavelength selection filter may be a plane shape, a shape with many holes in the surface, or a mesh shape, or various shapes such as a circle, an ellipse, a shape surrounded by other curves, a triangle, a rectangle, and other polygons. can be done with

An optical wavelength selection filter obtained by laminating two types of films having different refractive indices as described above may be further laminated on a separate sheet for use. The shape of the light wavelength selection filter when laminated on a separate sheet may be planar, may be a shape in which a large number of holes are opened on the surface, may be a mesh shape, or may be stacked in a spaced apart state such as stacked in a dotted shape. It is good also as a variety of shapes, such as a circular shape, an elliptical shape, a shape surrounded by other curves, a triangle, a rectangle, and other polygonal shapes.

It is also preferable that the surface of the light wavelength selection filter and/or the light wavelength conversion sheet has a concavo-convex shape. Having a concavo-convex shape here means that Rz in JIS B0601 (2001) is 1 µm or more when the surface roughness of the optical wavelength selection filter and/or the optical wavelength conversion sheet is measured. More preferably, Rz is 10 micrometers or more, and it becomes easy to obtain the following effect.

The first effect of the surface of the light wavelength selection filter and/or the light wavelength conversion sheet having a concavo-convex shape is easy activity. Since this activity is expressed by having a concavo-convex shape on the surface, it becomes possible to suppress occurrence of scratches when the optical wavelength selection filter and/or the optical wavelength conversion sheet are incorporated in a lighting device.

The second effect is extraction of light. The present inventors have found that, in a light wavelength conversion sheet, light is reflected in the light wavelength conversion sheet to cause a phenomenon in which the light is confined within the sheet like an optical fiber and the luminance is lowered. As a countermeasure thereof, the surface of the light wavelength selection filter and/or the light wavelength conversion sheet has a concavo-convex shape, so that light is extracted from the concavo-convex interface, reducing the light introduced into the optical wavelength conversion sheet, and improving the luminance. is obtained.

The third effect is optical path adjustment of light. While the light from the light emitting element, particularly the light emitting diode, travels toward the display side with relatively high directivity, the light from the light wavelength conversion sheet emits isotropically, which causes the luminance in front of the light source to decrease. When the surface of the light wavelength selection filter and/or the light wavelength conversion sheet has a concavo-convex shape, it becomes easy to achieve luminance improvement by adjusting the direction of light at the concavo-convex interface and condensing it in the front direction, in particular, a lighting device, a display Since other optical members can be omitted when forming the device, it also contributes to cost reduction.

In order to obtain the second and third effects more efficiently, it is preferable that the concavo-convex shape is a microlens shape, a prism shape, a substantially triangular shape, or a substantially semicircular shape. The microlens shape refers to substantially hemispherical irregularities, and the prismatic shape refers to substantially triangular irregularities. In the case of having such a shape, since the light path is condensed toward the display side, the front luminance of the lighting device or the display device is more remarkably improved.

As described above, the light-emitting element is a semiconductor element that emits light, and any suitable light-emitting element such as a blue or near-ultraviolet wavelength LED or laser can be used.

As described above, the light wavelength conversion sheet is a sheet that converts light of a specific wavelength into light of another wavelength, and is, for example, a sheet containing quantum dots or phosphors having a function of converting light wavelengths. A resin sheet containing quantum dots or phosphors may be used, or a film containing quantum dots or phosphors may be laminated on a sheet serving as a base material.

When using a light wavelength conversion sheet in which a film containing quantum dots or a phosphor is laminated on a sheet serving as a base material, the area of the light wavelength selection filter is preferably smaller than the area of the film containing quantum dots or a phosphor. It is preferable to make the area of the light wavelength selection filter smaller than the area of the film containing quantum dots or phosphors and partially arrange it in the lighting device because the color of light emitted from the lighting device can be partially adjusted efficiently.

As a combination for obtaining white light using a light emitting element and a light wavelength conversion sheet, for example, when a blue LED is used, blue light of a blue wavelength as a first wavelength emitted from the blue LED is converted to a yellow wavelength as a second wavelength. A light wavelength conversion sheet containing yellow quantum dots that emit yellow light may be used. In the case of using a near-ultraviolet LED, light of a near-ultraviolet wavelength that is the first wavelength emitted from the near-ultraviolet LED is converted to red quantum dots that emit red light of a red wavelength that is the second wavelength, and light of the near-ultraviolet wavelength is converted. and blue quantum dots that emit green light of the second wavelength, green wavelength, and blue quantum dots that emit blue light of the second wavelength, blue wavelength, by converting near-ultraviolet wavelength light.

As a quantum dot, CdSe with a ZnS shell is exemplified. In addition, core/shell luminescent nanocrystals containing CdSe/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS or CdTe/ZnS may be used.

Examples of the phosphor include SrGa ₂ S ₄ :Eu ²⁺ as the green phosphor and (Ca, Sr, Ba)S:Eu ²⁺ as the ^red phosphor. In the description of the phosphor material, the front of : represents the parent and the back represents the activator.

In addition, although white light is obtained in this embodiment, it is also possible to appropriately select the type of light emitting element or phosphor in order to obtain light of a desired color as light emitted from the lighting device.

In the first embodiment as well, it is preferable to provide an optical sheet on the emission side of the light wavelength selection filter as in FIG. 1 or FIG. desirable. A prism sheet, a microlens, or a polarization reflection film is conventionally advantageously used to improve the frontal luminance. In particular, when used in combination with a light wavelength conversion sheet, light once transmitted through the light wavelength conversion sheet is transferred onto an optical film. It is made to reflect and it can reflect and re-wavelength convert on the side of a light wavelength conversion sheet, and the effect of cost reduction by reducing the usage-amount of expensive quantum dots etc. is also acquired.

As a more preferable combination, the arrangement is made so that the angle formed by the direction in which the transmittance of the light wavelength selection filter at the wavelength λ3 is maximized and the direction in which the transmittance of the luminance enhancing film is maximized at the wavelength λ3 is 80° or more. can be heard The direction in which transmittance is maximized here is the direction in which polarized light of wavelength λ3 is incident perpendicularly to the film plane, and the polarization plane is rotated by 5° so that transmittance is maximized. As the direction in which transmittance of the optical wavelength selection filter and the luminance enhancement film is maximized is orthogonal, polarized light that could not be reflected by the optical wavelength selection filter can be efficiently reflected by the luminance enhancement film, further enhancing the effect of the optical wavelength selection filter. improvement is possible.

As the reflector 37, a light diffusive reflective film such as a white film may be used, but a regular reflective reflective film is more preferable. The specular reflectivity here refers to a glossiness of 100 or more measured at an incident angle of 60° and an outgoing angle of 60°, as in JIS Z8741 (1997). By using a regular reflective reflective film, it is possible to reflect light with high efficiency while suppressing scattering of the light reflected by the light selective wavelength filter or the light wavelength converted/emitted by the light wavelength conversion sheet, thereby suppressing color unevenness in the lighting device. effect is obtained.

(Second Embodiment)

8 is a schematic diagram of a lighting device according to a second embodiment of the present invention. A light wavelength conversion sheet 81 and a light wavelength selection filter 82 are provided, and a blue LED 83 is provided as a light emitting element at an end portion of the light guide plate 85 .

The blue LED 83, the light wavelength conversion sheet 81, and the light wavelength selection filter 82 are provided in this order.

The blue LED 83 is spaced apart from the light wavelength conversion sheet 81 and is provided. Light from the blue LED 83 enters from the end of the light guide plate 85 and is emitted while being guided by the light guide plate. According to this principle, light is emitted toward the light wavelength conversion sheet 81 .

The area of the light wavelength selection filter 82 is preferably smaller than the area of the light wavelength conversion sheet 81 . It is preferable to make the area of the light wavelength selection filter 82 smaller than the area of the light wavelength conversion sheet 81 and partially arrange it in the lighting device because the color of the light emitted from the lighting device can be partially adjusted efficiently.

Other aspects of the second embodiment are the same as those of the first embodiment.

(Third Embodiment)

A third embodiment, which is an example of the lighting device of the present invention, will be described using FIGS. 9 to 12 .

9 is a schematic diagram of a lighting device according to a third embodiment of the present invention. A light wavelength conversion sheet 91 and a light wavelength selection filter 92 are provided, and a blue LED 93 as a light emitting element is provided on a substrate 94 . Further, in order to reflect and diffuse the light from the light emitting element, a reflector 97 and a diffuser plate 98 are provided.

The blue LED 93, the light wavelength selection filter 92, and the light wavelength conversion sheet 91 are provided in this order.

The blue LED 93 is provided at a distance from the light wavelength conversion sheet 91 and emits light toward the light wavelength conversion sheet 91 .

The area of the light wavelength selection filter 92 is preferably smaller than the area of the light wavelength conversion sheet 91 . It is preferable to make the area of the light wavelength selection filter 92 smaller than the area of the light wavelength conversion sheet 91 and partially arrange it in the lighting device because the color of the light emitted from the lighting device can be partially adjusted efficiently.

In the third embodiment, the light wavelength selection filter 92 transmits light of a first wavelength emitted from the blue LED 93, and the light of the first wavelength is converted by the light wavelength conversion sheet 91. It reflects the light of the second wavelength that is generated.

The light wavelength selection filter 92 in the third embodiment has a peak wavelength for the light of the first wavelength emitted from the blue LED 93 (hereinafter, also referred to as the peak wavelength of the first wavelength). ) transmits 85% or more and is converted by the light wavelength conversion sheet 91 to generate light of a peak wavelength (hereinafter sometimes referred to as the peak wavelength of the second wavelength) with respect to light of the second wavelength. A filter that reflects 20% or more of That is, a filter having a transmittance of 85% or more at the peak wavelength of the first wavelength and a reflectance of 20% or more at the peak wavelength of the second wavelength. In addition, when there are two or more lights of the second wavelength, a filter having a reflectance of 20% or more with respect to all the lights of the second wavelength is referred to.

10 and 11 are diagrams showing optical paths when the light wavelength selection filter 92 is not present and when there is, respectively.

As shown in Fig. 10, when there is no light wavelength selection filter 92, of the green light and red light emitted from the light wavelength conversion sheet, the light emitted on the side opposite to the emission surface side is diffused in the lighting device.

As shown in Fig. 11, the light wavelength selection filter 92 transmits the blue light emitted by the blue LED, and part or all of the green light and red light emitted from the light wavelength conversion sheet are emitted to the side opposite to the emission surface side. is reflected, and green light and red light are emitted to the side of the emission surface in the vicinity provided with the light wavelength selection filter. Therefore, the blueness of the light emitted to the emission surface side in the vicinity of the light wavelength selection filter 92 is lower than that of the light emitted to the emission surface side in the case of FIG. 10, that is, when there is no optical wavelength selection filter 92.

According to this principle, the color unevenness of the lighting device is improved by partially arranging the light wavelength selection filter 92 in a portion of high blueness (a portion where the effect of the light emission color of the light emitting element is strong), such as near the end of the lighting device. can do.

When the optical wavelength selection filter 92 is used, color adjustment can be performed with less light loss compared to other color adjustment methods that reduce blueness by absorbing blue light.

The transmittance of the light wavelength selection filter 92 at the peak wavelength of the first wavelength is preferably 85% or more, more preferably 87% or more, and still more preferably 90% or more.

The optical wavelength selection filter 92 preferably has a reflectance of 20% or more at the peak wavelength of the second wavelength, more preferably 30% or more, still more preferably 70% or more, and particularly preferably 90% or more.

The light wavelength selection filter 92 also preferably satisfies the following formula (1). Equation (1) below indicates that the change in transmittance between the wavelength band where light is reflected and the wavelength band where light is transmitted is steep, and as |λ2-λ3| becomes smaller, the wavelength band that reflects light changes more rapidly from the wavelength band that transmits it. . Blue light is converted in the optical wavelength conversion sheet from the wavelength band that transmits from the reflected wavelength band, that is, the wavelength band that transmits the blue light emitted by the blue LED as described in the third embodiment, and reflects the green light of the green wavelength that is the second emission wavelength. By rapidly changing the desired wavelength range, it is possible to selectively and efficiently transmit only blue light while reflecting green light or red light, making it easy to obtain the maximum effect of the light wavelength selection filter.

|λ2-λ3|≤50 (where λ1<λ2, λ1<λ3) (1)

λ1: Emission wavelength of the light emitting element (nm)

λ2: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 70%

λ3: Wavelength (nm) at which the transmittance of the optical wavelength selection filter is 30%.

The light wavelength selection filter 92 may be laminated on the light wavelength conversion sheet 91 as shown in FIG. 12 , for example.

In the third embodiment as well, it is preferable to provide an optical sheet on the emission side of the light wavelength selection filter as in FIG. 1 or FIG. , It is preferable to arrange so that the angle between the direction in which transmittance of the light wavelength selection filter at wavelength λ3 is maximized and the direction in which transmittance in wavelength λ3 of the luminance enhancement film is maximized is 10° or less. Since the direction in which the transmittance of the light wavelength selection filter and the luminance enhancement film is maximized is parallel, the light reflected from the luminance enhancement film to the optical wavelength conversion sheet and the optical wavelength selection filter is efficiently reflected by the optical wavelength selection filter to the light emitting element. Reflection can be suppressed, and an effect of suppressing color unevenness of the lighting device is obtained.

Other aspects of the third embodiment are the same as those of the first embodiment.

(Fourth Embodiment)

13 is a schematic diagram of a lighting device according to a fourth embodiment of the present invention. A light wavelength conversion sheet 131 and a light wavelength selection filter 132 are provided, and a blue LED 133 is provided as a light emitting element at an end of the light guide plate 135 .

The blue LED 133, the light wavelength selection filter 132, and the light wavelength conversion sheet 131 are provided in this order.

The blue LED 133 is spaced apart from the light wavelength conversion sheet 131 and is provided. Light from the blue LED 133 enters from the end of the light guide plate 135 and is emitted while being guided by the light guide plate. According to this principle, light is emitted toward the light wavelength conversion sheet 131 .

The area of the light wavelength selection filter 132 is preferably smaller than the area of the light wavelength conversion sheet 131 . It is preferable to make the area of the light wavelength selection filter 132 smaller than the area of the light wavelength conversion sheet 131 and partially arrange it in the lighting device because the color of the light emitted from the lighting device can be partially adjusted efficiently.

Other aspects of the fourth embodiment are the same as those of the third embodiment.

(Fifth Embodiment)

A fifth embodiment, which is an example of the lighting device of the present invention, will be described using FIGS. 14 to 17 .

14 is a schematic diagram of a lighting device according to a fifth embodiment of the present invention. A first light wavelength conversion sheet 146 and a second light wavelength conversion sheet 141 are provided, and a blue LED 143 as a light emitting element is installed on the substrate 144 . In order to reflect and diffuse the light from the light emitting element, a reflector 147 and a diffuser plate 148 are provided.

The first light wavelength conversion sheet 146, the blue LED 143, and the second light wavelength conversion sheet 141 are provided in this order.

The blue LED 143 is provided apart from the second light wavelength conversion sheet 141 and emits light toward the second light wavelength conversion sheet 141 .

The area of the first light wavelength conversion sheet 146 is preferably smaller than the area of the second light wavelength conversion sheet 141 . If the area of the first light wavelength conversion sheet 146 is made smaller than the area of the second light wavelength conversion sheet 141 and partially disposed in the lighting device, the color of the light emitted from the lighting device can be partially adjusted efficiently. desirable.

15 and 16 are diagrams showing optical paths when the first optical wavelength selection filter 146 is not present and when the first light wavelength selection filter 146 is present, respectively.

15 and 16, part of the blue light emitted from the blue LED toward the second light wavelength conversion sheet 141 is reflected on the surface of the diffusion plate 148 and emitted to the side opposite to the emission surface side. Also, a part of the light is reflected on the surface of the other optical sheet or the surface of the second light wavelength conversion sheet, and is emitted on the side opposite to the emission surface side. It repeats that the light emitted to the side opposite to the emission surface side is reflected by the reflecting plate and goes to the emission surface side, and a part of it is reflected again by the surface of the diffuser plate 148 or the like and emitted to the side opposite to the emission surface side.

As shown in FIG. 16, when there is a first light wavelength conversion sheet 146, the blue light emitted from the side opposite to the emission surface side has a peak at a wavelength different from the peak wavelength of the blue wavelength, such as green light or red light. After being converted into light, it is emitted to the emission surface side by the reflecting plate. On the other hand, as shown in FIG. 15, when there is no first light wavelength conversion sheet 146, the blue light emitted to the side opposite to the emission surface side is emitted to the emission surface side by the reflector without wavelength conversion. Therefore, when there is the first light wavelength conversion sheet 146, the blueness of the light emitted to the emission surface side in the vicinity of the first light wavelength conversion sheet 146 is the case of FIG. 15, that is, the first light wavelength conversion sheet ( 146), it is reduced more than the light emitted to the emission surface side.

According to this principle, color unevenness of the lighting device is improved by partially disposing the light wavelength conversion sheet 146 in a portion of high blueness (a portion where the effect of the light emission color of the light emitting element is strong), such as near the end of the lighting device. can do.

When the first light wavelength conversion sheet 146 is used, color adjustment can be performed with a small light loss compared to other color adjustment methods that reduce blueness on the principle of absorbing blue light.

You may laminate|stack the 1st light wavelength conversion sheet 146 on a reflecting plate, as shown in FIG. 17, for example.

The first light wavelength conversion sheet 146 may contain a quantum dot or a phosphor in a reflecting plate. A sheet containing quantum dots or phosphors in a reflector becomes a sheet having a wavelength conversion function and a reflection function.

The shape of the first light wavelength conversion sheet may be planar, may be a shape with a large number of holes in the surface, may be a mesh shape, circular, elliptical, other curved shapes, triangles, squares, other polygons, etc. It may be made in various shapes.

In addition, the first light wavelength conversion sheet is a sheet that converts light of a specific wavelength into light of another wavelength as described above, and is, for example, a sheet containing quantum dots or phosphors having a function of converting light wavelengths. A resin sheet containing quantum dots or a phosphor may be used, or a film containing quantum dots or a phosphor may be laminated on a sheet serving as a base material. Moreover, you may use a reflector as a base material. The shape of the quantum dot or phosphor-containing film laminated on the sheet serving as the base material may be a shape in which a large number of holes are opened in the surface, or may be a mesh shape, or may be stacked in a spaced state such as stacked in a dotted shape, circular or elliptical. , a shape surrounded by other curves, a triangle, a rectangle, and other polygons.

In the case of using a light wavelength conversion sheet obtained by laminating a film containing quantum dots or phosphors on a sheet serving as a base material, the area of the film containing quantum dots or phosphors of the first light wavelength conversion sheet is equal to that of the second light wavelength conversion sheet. It is preferable to make it smaller than the area of the film containing a quantum dot or a fluorescent substance. If the area of the film containing quantum dots or phosphors of the first light wavelength conversion sheet is made smaller than the area of the film containing quantum dots or phosphors of the second light wavelength conversion sheet and partially disposed in the lighting device, the emission light of the lighting device can be efficiently reduced. This is preferable because the color can be partially adjusted.

Other aspects of the fifth embodiment are the same as those of the first embodiment.

(Sixth Embodiment)

18 is a schematic diagram of a lighting device according to a sixth embodiment of the present invention. A first light wavelength conversion sheet 186 and a second light wavelength conversion sheet 181 are provided, and an end portion of the light guide plate 185 is provided with a blue LED 183 as a light emitting element.

The first light wavelength conversion sheet 186, the blue LED 183, and the second light wavelength conversion sheet 181 are provided in this order.

The blue LED 183 is provided to be spaced apart from the second light wavelength conversion sheet 181 . Light from the blue LED 183 enters from the end of the light guide plate 185 and is emitted while being guided by the light guide plate. According to this principle, light is emitted toward the second light wavelength conversion sheet 181 .

The area of the first light wavelength conversion sheet 186 is preferably smaller than the area of the second light wavelength conversion sheet 181 . When the area of the first light wavelength conversion sheet 186 is made smaller than the area of the second light wavelength conversion sheet 181 and partially disposed in the lighting device, the color of the light emitted from the lighting device can be partially adjusted efficiently. desirable.

Other aspects of the sixth embodiment are the same as those of the fifth embodiment.

Example

Hereinafter, the present invention will be described in detail by examples, but the present invention is not limited by these examples. In addition, the measurement method and evaluation method in this Example are shown below.

[Measurement method and evaluation method]

(1) Spectral spectrum of the lighting device

The spectral spectrum of the central portion of the lighting device A was measured in a dark room under the following conditions using the following spectroradiometer. In determining the center portion, the center portion of the prism film (155 mm x 98 mm) provided on the uppermost surface of the lighting device A was taken as the center portion of the lighting device A. Further, the distance between the spectroradiometer used in the lighting device and the display was set to 500 mm.

・Spectroradiometer CS-1000A (manufactured by Konica Minolta Sensing Co., Ltd.)

Objective lens: macro objective lens

·Measurement mode: AUT0.

(2) spectral reflectance of optical wavelength selection filter

Samples were cut out to 50 mm x 50 mm. Subsequently, the relative reflectance at an incident angle of ? = 10 degrees was measured using a spectrophotometer (U-4100 Spectrophotometer manufactured by Hitachi Seisakusho Co., Ltd.). The inner wall of the accessory integrating sphere is barium sulfate, and the standard plate is aluminum oxide. The measurement wavelength was 250 nm to 1,200 nm, the slit was 2 nm (visible)/automatic control (infrared), the gain was set to 2, and the measurement was performed at a scanning speed of 600 nm/min. The back side of the sample was coated black with oil ink.

(3) Optical wavelength selection filter, spectral transmittance of optical sheet

Samples were cut out to 50 mm x 50 mm. Transmittance measurement was performed with a basic configuration using a spectrophotometer (U-4100 Spectrophotomater) supplied by Hitachi Seisakusho Co., Ltd. (incidence angle 0°). The measurement was based on the white plate of aluminum oxide attached to the device, and as the measurement conditions, the slit was set to 2 nm (visible) / automatic control (infrared), the gain was set to 2, and the scanning speed was measured at 600 nm / min. . In addition, when measuring the transmittance including the polarization component, an attached polarizer manufactured by Glan-Taylor was installed, and after fixing the sample in a certain direction, the polarizer was rotated by 5 ° to measure the transmittance, and the angle at which the transmittance was maximized was measured. .

(4) Spectral spectrum of the light wavelength conversion sheet

A sample was cut out to 50 mm x 50 mm, the back side of the sample was coated black with oil ink, and measurement was performed using the following spectrophotometer.

・Spectrophotometer CM-2600d (manufactured by Konica Minolta Sensing Co., Ltd.)

・White calibration plate CM-A145 (manufactured by Konica Minolta Sensing Co., Ltd.)

・Target mask CM-146 (for φ8mm).

(5) Color coordinates and luminance of lighting equipment

Illumination device A was configured as described in Examples 1 to 10, and the color coordinates (x value, y value) of the central portion thereof were measured using a spectroradiometer described below under the following conditions in a dark room. In determining the central part, the central part of the prism film (155 mm x 98 mm) provided on the uppermost surface of the lighting device A was taken as the central part. Further, the distance between the spectroradiometer used in the lighting device and the display was set to 500 mm.

・Spectroradiometer CS-1000A (manufactured by Konica Minolta Sensing Co., Ltd.)

Objective lens: macro objective lens

·Measurement mode: AUTO

(6) Glossiness

According to the method specified in JIS-Z8741 (1997), the 60° specular gloss was measured using a digital variable angle gloss meter UGV-5D manufactured by Suga Instruments. The measurement was performed at n=5, and the average value excluding the maximum value and the minimum value was used as glossiness.

[Lighting device used for evaluation (lighting device A)]

As a lighting device A in which a light source is a blue LED and a light wavelength conversion sheet is mounted, a Kindle Fire HDX 7 backlight was used. The size of the light wavelength conversion sheet was 158 mm x 98 mm. In Example 9, the light wavelength conversion sheet mounted on the lighting device A was used as the second light wavelength conversion sheet.

19 is a simplified view of the lighting device A. It was composed of a blue LED 193, a light guide plate 195, a reflective film 197 having a glossiness of 930 (Example 6 is excluded), a light wavelength conversion sheet 191, and a prism sheet 199 (2 sheets). .

As a result of measuring the spectral spectrum of the lighting device A, the blue wavelength of the blue light emitted from the blue LED has a peak at 450 nm, and the green wavelength of the green light converted by the light wavelength conversion sheet and the red wavelength of the red light have peaks at 550 nm and 610 nm, respectively. there was

[Example 1]

Optical wavelength selection filter A was obtained by the method shown below.

As polyester A, polyethylene terephthalate having an intrinsic viscosity of 0.8 was used. Further, as polyester B, a blend chip in which 62% by mass of co-polyester copolymerized with 30 mol% of cyclohexanedimethanol and 38% by mass of polyethylene terephthalate were dispersed was used. These Polyester A and Polyester B were supplied to the extruder after drying, respectively.

Polyester A and polyester B are each in a molten state at 280 ° C. in an extruder, and after passing through a filter while metering so that the discharge ratio is polyester A composition / polyester B composition = 1.66 / 1 with a gear pump, feed joined in the block. The joined polyester A and polyester B are supplied to the static mixer, joined in the 501-layer feed block, and alternately A/B/A in the thickness direction... It was set as the laminated body in which 501 layers were laminated|stacked by B/A.

The laminate composed of the 501 layers obtained in this way was supplied to a T-die, molded into a sheet shape, and rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25° C. while applying static electricity.

The obtained cast film was heated with a roll group set at 85 ° C. to 100 ° C., stretched 3.3 times in the machine direction, guided the uniaxially stretched film to a tenter, preheated with hot air at 100 ° C., and then at a temperature of 110 ° C. It was stretched 3.8 times in the width direction. The stretched film was subjected to heat treatment with a relaxation rate of 3% and hot air at 150°C in a tenter, cooled slowly to room temperature, and then wound up. A light wavelength selection filter A having a thickness of 40 μm and a thickness of each layer varying stepwise from 43 to 83 nm was obtained.

As a result of measuring the spectral reflectance and spectral transmittance of the optical wavelength selection filter A, the reflectance at 450 nm was 69%, the transmittance at 550 nm was 88%, and the transmittance at 610 nm was 90%.

The light wavelength selection filter A was cut out to 60 mm x 98 mm and placed between the light wavelength conversion sheet and the prism sheet of the lighting device A. When arranging, the 60 mm side was parallel to the long side of the lighting device, and the center of the light wavelength selection filter A was arranged so as to be the center of the lighting device A. In determining the central portion of the lighting device A, the central portion of the prism film (155 mm x 98 mm) installed in the lighting device A was defined as the central portion.

Color coordinates (x value, y value) and luminance when the optical wavelength selection filter A was disposed, and color coordinates (x value, y value) and luminance when not disposed were measured. The evaluation results are listed in Table 1.

[Example 2]

Color coordinates (x-value, y-value ), luminance, and color coordinates (x value, y value) when not arranged, and luminance were measured. The evaluation results are shown in Table 1.

[Example 3]

A polarization reflection film having a degree of polarization of 90% was placed on the prism sheet of Example 1 so that the direction in which the transmittance of the light selective wavelength filter A was maximized and the direction in which the transmittance of the polarization reflection film was maximized were orthogonal to each other at 90°. Color coordinates (x value, y value) and luminance when the light wavelength selection filter A is disposed in the same manner as in Example 1 except for the arrangement, and color coordinates (x value, y value) when not disposed , the luminance was measured. The evaluation results are listed in Table 1.

[Example 4]

As the light wavelength selection filter B, polyester B is copolymerized with 25 mol% of spiroglycol and 30 mol% of cyclohexanedicarboxylic acid, and the thickness is 70 μm, and the thickness of each layer is gradually changed from 76 to 145 nm. A light wavelength selection filter B was obtained in the same manner as in Example 1 except for the above.

As a result of measuring the spectral reflectance and spectral transmittance of the optical wavelength selection filter B, the transmittance at 450 nm was 90%, the reflectance at 550 nm was 34%, and the reflectance at 610 nm was 90%.

As the optical wavelength selection filter, the optical wavelength selection filter B was used, and the position of the optical wavelength selection filter was placed between the light guide plate of the lighting device A and the optical wavelength conversion sheet, in the same manner as in Example 1, the optical wavelength selection filter The color coordinates (x value, y value) and luminance when B was arranged, and the color coordinates (x value, y value) and luminance when B was not arranged were measured. The evaluation results are listed in Table 1.

[Example 5]

A polarization reflection film having a polarization degree of 90% was placed on the prism sheet of Example 4, and the direction in which the transmittance of the light-selective wavelength filter B was maximized was parallel to the direction in which the transmittance of the polarization reflection film was maximum. Other than that, in the same manner as in Example 4, color coordinates (x value, y value) and luminance when the light wavelength selection filter B is disposed, and color coordinates (x value, y value) and luminance when not disposed was measured. The evaluation results are listed in Table 1.

[Example 6]

Color coordinates (x value, y value), luminance, and arrangement in the case of arranging the light wavelength selection filter B in the same manner as in Example 4 except that the reflective film of Example 4 was a white film having a glossiness of 32 Color coordinates (x value, y value) and luminance were measured in the case of not being applied. The evaluation results are listed in Table 1.

[Example 7]

Surface irregularities were formed on the light wavelength selection filter B by the following method.

First, coating agent 1 was coated on the light wavelength selection filter B to form a coating film having a thickness of 5 μm.

(Applicator 1)

Adeka Optomer KRM-2199 (manufactured by Asahi Denka Kogyo Co., Ltd.) 10 parts by mass

Aaron oxetane OXT-221 (manufactured by Toagosei Co., Ltd.) 1 part by mass

Adeka Optomer SP170 (manufactured by Asahi Denka Kogyo Co., Ltd.) 0.25 parts by mass

A mold having a plurality of concave grooves in cross-sectional shape perpendicular to the longitudinal direction was pressed and covered on the surface coated with the coating agent 1, and 300 mJ/cm 2 of ultraviolet rays was irradiated from the back side of the coated surface with an ultra-high pressure mercury lamp to cure the coating agent. , the mold was released to obtain a lens shape. The lens shape obtained here had a prism shape with a pitch of 2 μm and a height of 1 μm.

Subsequently, it was installed under the light wavelength conversion sheet so that the formed lens shape became the upper surface.

Other configurations are the same as in Example 4, color coordinates (x value, y value) and luminance when the light wavelength selection filter B is disposed, color coordinates (x value, y value) when not disposed, Luminance was measured. The evaluation results are listed in Table 1.

[Example 8]

Color coordinates (x value, y value) when optical wavelength selection filter B is arranged in the same manner as in Example 4, except that 0.1 mass% of "OB-1" manufactured by Eastman Co., Ltd., which is an optical whitening agent, is added to polyester B. , luminance, color coordinates (x value, y value) and luminance when not arranged. The evaluation results are listed in Table 1.

[Example 9]

The 1st light wavelength conversion sheet A was obtained by the method shown below.

After vacuum drying 100 mass parts of polyethylene terephthalate pellets, it is supplied to the extruder A heated at 250 ° C. to 300 ° C. to form a polyester layer (first layer), and in the composite film forming apparatus having the extruder B, To form the ester layer (second layer), 77.5 parts by mass of a dried polyethylene terephthalate raw material and 20 parts by mass of a dried polymethylpentene resin (hereinafter sometimes abbreviated as PMP) manufactured by Mitsui Chemicals Co., Ltd. were mixed with polyethylene terephthalate as a phosphor. 2.5 parts by mass of master pellets (containing 400 µg/g of "Lumogen" F Yellow 083: manufactured by BASF as a phosphor relative to the total amount of master pellets) were mixed, and the PMP content in 100% by mass of the total amount of polyethylene terephthalate raw material After adjusting to 20% by mass and 10 μg/g of phosphor, and vacuum drying the polyethylene terephthalate raw material, it was supplied to an extruder B heated at 250 to 300° C., melted, and introduced into a composite spinneret for a 3-layer T die.

These polymers were laminated in three layers through a three-layer lamination apparatus so as to form A layer (first layer) / B layer (second layer) / A layer (first layer), and were molded into a sheet shape by T-die. Further, the unstretched film obtained by cooling and solidifying this sheet-like film on a cooling drum with a surface temperature of 10°C to 40°C is guided to a group of rolls heated to a temperature of 70°C to 98°C, longitudinally stretched 3.3 times in the longitudinal direction, and then passed through a cooling roll. Then, while holding both ends of the longitudinally stretched film with clips, it was guided to a tenter and transversely stretched 3.6 times in a direction perpendicular to the length in an atmosphere heated to 120°C. Thereafter, a heat setting temperature treatment of 180 to 240°C was performed in a tenter to obtain a film having a thickness of 150 µm.

Color coordinates (x value, y value), luminance, color coordinates (x value, y value) and luminance when not arranged were measured. The evaluation results are listed in Table 1.

[Example 10]

To form the polyester layer (second layer), master pellets obtained by adding a phosphor to polyethylene terephthalate (master 0.25 parts by mass of "Lumogen" F Yellow 083 (manufactured by BASF, containing 400 μg/g) as a phosphor with respect to the total amount of pellets was mixed, and the PMP content in 100 mass% of the total amount of polyethylene terephthalate raw material was 20 mass%, and the phosphor was 1 μg/g. Except having adjusted so that it might become g, it carried out similarly to Example 4, manufactured the film, and set it as 1st light wavelength conversion sheet B.

Color coordinates (x value, y value), luminance, color coordinates (x value, y value) and luminance when not arranged were measured. The evaluation results are listed in Table 1.

[evaluation]

Measurement and evaluation of the lighting device were performed according to the above embodiment. The results are shown in Table 1. In addition, an xy chromaticity diagram is shown in FIG. 20 .

As shown in Table 1, when the optical wavelength selection filters A and B and the first optical wavelength conversion sheets A and B are disposed, compared to the case where they are not disposed, either the x value or the y value is the same value. Whichever one got bigger, both got bigger. Example 2 had the greatest change in x value and y value, followed by Example 1.

Here, as shown in the xy chromaticity diagram of FIG. 20, the coordinate position of a color with strong blueness is in the direction in which the values of x and y values decrease, and the decrease in blueness means that, on the contrary, the x and y values that the value increases.

When the optical wavelength selection filters A and B and the first optical wavelength conversion sheets A and B are disposed, compared to the case where they are not disposed, either the x value or the y value is the same value, whichever is larger, or both is increasing, i.e., the blueness is reduced, and if the light wavelength selection filters A and B and the first light wavelength conversion sheets A and B are partially disposed in the vicinity of a portion of the lighting device having a high blueness, the color unevenness of the lighting device can be adjusted.

11, 21, 31, 81, 91, 131, 191... optical wavelength conversion sheet
141, 181... Second light wavelength conversion sheet
32, 82, 92, 132... Optical wavelength selection filter
13, 23, 33, 83, 93, 133, 143, 183, 193... blue LED
14, 24, 34, 94, 144... Board
85, 135, 185, 195... light guide plate
146, 186... First light wavelength conversion sheet
17, 37, 97, 147, 187, 197... reflector
18, 28, 38, 98, 148... diffuser
19, 29... optical sheet
199... prism sheet
20... Liquid crystal panel (display panel)
30... lighting device

Claims (15)

an optical wavelength conversion sheet;
an optical wavelength selection filter;
light emitting element
It is a lighting device having a,
A light emitting element, a light wavelength conversion sheet, and a light wavelength selection filter are provided in this order,
an area of the optical wavelength selection filter is smaller than an area of the optical wavelength conversion sheet;
The light emitting element is provided spaced apart from the light wavelength conversion sheet,
The optical wavelength selection filter reflects light of a first wavelength emitted from the light emitting element, transmits light of a second wavelength generated by converting the light of the first wavelength in the optical wavelength conversion sheet, and transmits light of the optical wavelength conversion sheet. 85% or more of the light of the peak wavelength (the peak wavelength of the second wavelength) is transmitted to the light of the second wavelength converted by A filter that reflects 20% or more of light of a peak wavelength), light of a first wavelength is light having a peak at a specific wavelength, and light of a second wavelength is light having a peak at a wavelength different from light of the first wavelength. ego,
The lighting device, characterized in that the light wavelength selection filter satisfies the following formula (1).
|λ2-λ3|≤50 (where λ1<λ2, λ1<λ3) (1)
λ1: Emission wavelength of the light emitting element (nm)
λ2: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 70%
λ3: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 30% an optical wavelength conversion sheet;
an optical wavelength selection filter;
light emitting element
It is a lighting device having a,
A light emitting element, a light wavelength selection filter, and a light wavelength conversion sheet are provided in this order,
an area of the optical wavelength selection filter is smaller than an area of the optical wavelength conversion sheet;
The light emitting element is provided spaced apart from the light wavelength conversion sheet,
The light wavelength selection filter transmits light of a first wavelength emitted from the light emitting element, reflects light of a second wavelength generated by converting the light of the first wavelength by the light wavelength conversion sheet, and emits light from the light emitting element. 85% or more of the light of the peak wavelength (peak wavelength of the first wavelength) is transmitted to the light of the first wavelength, and the light of the second wavelength generated by being converted by the light wavelength conversion sheet has a peak. A filter that reflects 20% or more of light of a wavelength (peak wavelength of a second wavelength), wherein the light wavelength selection filter satisfies Expression (1) below.
|λ2-λ3|≤50 (where λ1<λ2, λ1<λ3) (1)
λ1: Emission wavelength of the light emitting element (nm)
λ2: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 70%
λ3: Wavelength (nm) at which the transmittance of the light wavelength selection filter is 30% The lighting device according to claim 1 or 2, wherein the optical wavelength selection filters are laminated films of thermoplastic resins having different refractive indices that are transparent in the visible light region alternately. The lighting device according to claim 1 or 2, wherein a surface of the light wavelength selection filter and/or the light wavelength conversion sheet has a concavo-convex shape. The lighting device according to claim 1 or 2, wherein a plurality of light emitting elements are provided corresponding to the entire surface of the light wavelength conversion sheet. The lighting device according to claim 1 or 2, further comprising a light guide plate disposed in an optical path of light emitted from the light emitting element from the light emitting element to the light wavelength conversion sheet. The lighting device according to claim 6, wherein a plurality of light emitting elements are provided along an end of the light guide plate. The method according to claim 1 or 2, further comprising a luminance enhancing film, and further comprising providing the luminance enhancing film on the emitting side of any member of the light emitting element, the optical wavelength sheet, or the optical wavelength selection filter. lighting device. 9. The method of claim 8 , wherein an angle formed between a direction in which transmittance of the light wavelength selection filter at a wavelength of λ3 is maximized and a direction in which transmittance of the luminance enhancement film is maximized at a wavelength of λ3 is 10° or less. lighting device. The method according to claim 8, characterized in that an angle formed between a direction in which transmittance of the optical wavelength selection filter at a wavelength of λ3 is maximized and a direction in which transmittance of the luminance enhancement film is maximized at a wavelength of λ3 is 80° or more. lighting device. The method according to claim 1 or 2, further comprising a regular reflective reflective film, and furthermore, the regular reflective reflective film is provided on the opposite side of the emission side of any member of the light emitting element, the optical wavelength sheet, or the optical wavelength selection filter. A lighting device characterized in that made by. A display device including a display panel and a lighting device installed adjacent to the display panel,
the lighting device,
A display device characterized by being the lighting device according to claim 1 or 2. delete delete delete

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