TWI726849B - Optical film, light-emitting device having the optical film, and display having the light-emitting device - Google Patents

Abstract

An optical film includes a first substrate, a second substrate, a diffusion layer, and a plurality of microstructures. The first substrate includes a first surface and a light incident surface opposite to the first surface. The second substrate is spaced apart from the first substrate, and includes a second surface facing the first surface, and a light-emitting surface opposite to the second surface. The diffusion layer is located between the first substrate and the second substrate, and includes a plurality of quantum dots. The microstructures are formed on the light incident surface of the first substrate. Wherein, a first color light can pass through the diffusion layer through the light incident surface of the first substrate, and be emitted from the light exit surface of the second substrate, and the first color light can excite the quantum dots to emit a wavelength The second color light that is greater than the wavelength of the first color light. The present invention also provides a light-emitting device with the optical film, and a display with the light-emitting device.

Description

Optical film, light-emitting device having the optical film, and display having the light-emitting device

The present invention relates to an optical film, a light-emitting device, and a display, in particular to an optical film that can improve color gamut, a light-emitting device using the optical film, and a display using the light-emitting device.

Compared with traditional organic fluorescent materials, quantum dot fluorescent materials have better luminous efficiency, and quantum dot fluorescent materials of different materials or particle sizes will emit excitation light of different wavelengths after being irradiated by the excitation light source. Therefore, At present, it has received great attention from related technical fields.

Generally speaking, when a quantum dot fluorescent material is applied to a backlight module of a display, a light emitting diode unit with a single color is mainly used as an excitation light source to excite quantum dot fluorescence of different materials or particle sizes. Materials, and light sources that generate a variety of different colors of light, and then mix the different colors of light with each other as the backlight source of the backlight module of the display. For example, a blue light emitting diode is generally used as the excitation light source to excite quantum dot fluorescent materials of different materials or particle sizes to generate red light and green light, and then mix the red light, green light, and blue light. The way to form white light as the backlight source of the backlight module.

However, the white light generated by mixing light in the foregoing manner will reduce the overall color purity due to the continuous distribution of the light spectrum of each color light. That is to say, when the foregoing backlight module is applied to a display, it will cause the display to suffer The color representation range (color gamut) is reduced, causing some actual colors to be unrepresented. Among them, the color gamut is the range area formed by the number of colors that the display can express, that is, the range of colors that it can express, and this color range is represented by red (R), The area of the triangle enclosed by the coordinates of the three primary colors of green (G) and blue (B). The larger the area of the triangle, the wider the color gamut, and the richer and more realistic colors it can express.

It can be seen that one of the main factors affecting the color gamut rendering ability of the display depends on the backlight source emitted by the backlight module. When the backlight module applied to the display can emit a high color gamut backlight, the display can display richer colors, and can present colors closer to the object itself with vivid colors; conversely, low color gamut The backlight will cause the color displayed by the display to deviate, and cannot fully express the actual color of the object.

Therefore, how to make the backlight source emitted by the backlight module have a high color gamut range so that the display has excellent color performance is a problem to be solved by those skilled in the art.

Therefore, the object of the present invention is to provide an optical film.

Therefore, the optical film of the present invention can excite a second color light having a wavelength greater than that of the first color light after a first color light enters the optical film. The optical film includes a first substrate and a second color light. Substrate, a diffusion layer, and multiple microstructures.

The first substrate includes a first surface and a light incident surface opposite to the first surface.

The second substrate is spaced apart from the first substrate, and includes a second surface facing the first surface, and a light-emitting surface opposite to the second surface.

The diffusion layer is located between the first substrate and the second substrate, and includes a plurality of quantum dots.

The microstructures are formed on the light incident surface of the first substrate.

Wherein, the first color light can pass through the diffusion layer through the light-incident surface of the first substrate, and is emitted from the light-emitting surface of the second substrate, and the first color light can excite the quantum dots to emit the first Two-color light.

In addition, another object of the present invention is to provide a light emitting device.

Therefore, the light-emitting device of the present invention includes: an optical film as described above, and a light-emitting unit.

The light-emitting unit is located on the side of the light incident surface of the first substrate of the optical film, and can emit a first color light, and the first color light can be transferred from the first substrate through the microstructures. The light incident surface is incident on the diffusion layer and emitted from the light exit surface of the second substrate, and the first color light can excite the quantum dots to emit a second color light with a wavelength greater than that of the first color light.

Another object of the present invention is to provide a display.

Therefore, the display of the present invention includes: the light-emitting device as described above, and a panel.

The panel is located on the side of the light-emitting surface of the second substrate of the optical film of the light-emitting device, and generates an optical effect by the light emitted by the light-emitting device to present a predetermined image.

The effect of the present invention is that by arranging the microstructures on the light incident surface of the first substrate, the first color light can pass through the microstructures to change its light path and excite more of the diffusion layer in the diffusion layer. Equivalent quantum dots, so that the light intensity of the color light can be more uniformly distributed, in order to achieve the purpose of wide color gamut.

1 and 2, a first embodiment of the optical film 10 of the present invention includes a first substrate 1, a second substrate 2, and a substrate located between the first substrate 1 and the second substrate 2 Between the diffusion layer 3 and a plurality of microstructures 4 formed on the first substrate 1 and the second substrate 2.

The first substrate 1 includes a first surface 11 and a light incident surface 12 opposite to the first surface 11. The second substrate 2 is spaced apart from the first substrate 1 and includes a second surface 21 facing the first surface 11 and a light emitting surface 22 opposite to the second surface 21. Wherein, the first substrate 1 and the second substrate 2 are made of a flexible transparent material. The flexible transparent material suitable for this embodiment can be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polycarbonate (polycarbonate, PC), but not limited to this. In this embodiment, the first substrate 1 and the second substrate 2 are illustrated by using polyethylene terephthalate (PET) as an example.

The diffusion layer 3 is located between the first surface 11 of the first substrate 1 and the second surface 21 of the second substrate 2 and has a plurality of quantum dots 31. The quantum dots 231 are nanocrystalline semiconductor materials, mainly semiconductor quantum dots synthesized from II-VI or III-V group compounds. After being irradiated by excitation light, they emit a second order different from excitation light. Light. The quantum dots 231 can change the emission wavelength after being irradiated by the excitation light through the selection of materials or the adjustment of the size of the particle size, thereby emitting color lights of different colors. It should be noted that the diffusion layer 3 can be prepared by first dispersing the quantum dots 31 in a colloidal system, and then coating them on either the first surface 11 or the second surface 21 by a coating method. A glue film is formed, and then, depending on the material of the quantum dots 31, whether to anneal is selected, and the diffusion layer 3 can be obtained. Since the preparation of the diffusion layer 3 and the material selection of the quantum dots 31 are known in the art, no further description is given.

The microstructures 4 are respectively formed adjacent to and connected to the light incident surface 12 of the first substrate 1 and the light exit surface 22 of the second substrate 2, and the optical film 10 further includes a plurality of strips surrounding the microstructures 4 The bottom groove5.

Specifically, in the first embodiment, the microstructures 4 are semicircular microlenses that project away from the light-incident surface 12 and the light-emitting surface 22 to allow light to enter or leave. When the optical film 10 refraction occurs, the light path of the optical film 10 can be changed. It should be noted that although the microstructures 4 of this embodiment are protruding microlenses with a semicircular shape, since the microstructures 4 are closely connected to each other, the edge of each microstructure 4 will be Due to the close proximity, it presents a regular hexagonal pattern as shown in the top view of FIG. 1, but the close arrangement of each microstructure 4 is not limited to this, and it may also be arranged in a rectangular array, or may be irregularly chaotic. Number distribution.

Preferably, each microstructure 4 has a vertex P located at the geometric center, and a height H from the light incident surface 12 and the light exit surface 22 to the vertex P. Each of the bottom grooves 5 has a radius of curvature R, and two adjacent parallel bottom grooves 5 have an array pitch W.

More preferably, in this embodiment, the aspect ratio of the height H of each microstructure 4 to the array pitch W is between 3.0% and 60%; wherein, the height H of each microstructure 4 is It is between 1.0 and 40 μm, the array pitch W is between 6.0 μm and 60 μm, and the radius of curvature R is between 1.0 μm and 7.0 μm.

A second embodiment of the optical film 10 of the present invention is substantially the same as the first embodiment. The difference is that the microstructures 4 are upwardly convex and generally cone-shaped microlenses, and the microstructures 4 They are also closely connected to each other, so that the edges of the microstructures 4 are in a regular hexagonal pattern due to the close proximity, and the aspect ratio of the height H of each microstructure 4 to the array pitch W is between 3.0% and 60 %; The radius of curvature R is between 1.0 μm and 7.0 μm; the height H of each microstructure 4 is between 1 μm and 40 μm; and the array spacing W is between 6 μm and 60 μm.

A third embodiment of the optical film 10 of the present invention is substantially the same as the first embodiment. The difference is that the microstructures 4 are irregularly shaped microlenses that protrude upward, because the microstructures 4 are also closely connected to each other, so that the edges of the microstructures 4 are in a regular hexagonal pattern due to the close proximity. Therefore, the irregular shape described in the third embodiment refers to a microlens projected upward to form different shapes and heights. , And the height-to-width ratio of the height H of each microstructure 4 to the array pitch W is between 3% and 60%; the height H of each microstructure 4 is between 1 μm and 40 μm; the array pitch W Between 6μm~60μm.

In conjunction with FIG. 3, FIG. 3 shows a light-emitting device 7 formed by using the optical film 10 of the present invention and a light-emitting unit 6 together. It should be noted that the optical film 10 may be one of the first embodiment to the third embodiment, and the optical film 10 in the light-emitting device 7 shown in FIG. 3 is based on the first embodiment. Illustrate by example. The application range of the light-emitting device 7 is not particularly limited, and can be applied to related fields such as lighting equipment or backlight modules.

Specifically, the light emitting unit 6 is located on one side of the light incident surface 12 of the first substrate 1 and can emit a first color light λ ₁ , so that the first color light λ _{1 is} incident on the optical film 10 Then, a second color light λ ₂ (not shown) with a wavelength greater than that of the first color light λ _{1 can be excited.}

After the first color light λ ₁ is emitted by the light-emitting unit 6, it will be refracted by the microstructures 4 of the first substrate 1, and then be incident on the light-incident surface 12 through the diffusion layer 3, and simultaneously excite the The quantum dots 31 in the diffusion layer 3 emit the second color light λ ₂ , the excited second color light λ ₂ and the first color light λ ₁ are mixed with each other, and then the second color light λ 1 The light-emitting surface 22 of the material 2 emits.

In detail, the diffusion layer 3 of the optical film 10 usually has the quantum dots 31 with two or more different particle diameters or materials to enable the first color light λ ₁ emitted by the light-emitting unit 6 to excite The quantum dots 31 generate light of different colors. The diffusion layer 3 of the light-emitting device 7 of the present invention uses two kinds of quantum dots 31 with different particle diameters as an example, so that the first color light λ ₁ excites the two kinds of quantum dots 31 to generate the second color light λ ₂ , And a third color light λ ₃ (not shown) with a wavelength greater than the second color light λ ₂ , and then mix with each other.

In more detail, the light-emitting unit 6 of the present invention may include a plurality of light-emitting diodes (LEDs) that emit blue light as a light-emitting source, so that blue light is used as the first color light λ ₁ and used in the diffusion layer 3 Two kinds of quantum dots 31 that can be excited by blue light to generate green light and red light, namely, the first color light λ ₁ , the second color light λ ₂ , and the third color light λ ₃ are blue light and green light, respectively, and Red light. In other words, when blue light enters the diffusion layer 3 to excite the quantum dots 31 to generate green light and red light, the three colors of light will be mixed with each other into white light and light will be emitted from the light exit surface 22. Since the material selection and detailed structure of the light-emitting unit 6 are well-known to those in the art, and are not the technical focus of the present invention, no further description will be given.

It should be noted here that because the optical film 10 of the present invention is provided with the microstructures 4, and further by allowing the microstructures 4 to have a specific aspect ratio (H/W=3%~60%) and Let the radius of curvature R of the bottom groove 5 be between 1.0 μm and 7.0 μm, so that the first color light λ ₁ emitted by the light-emitting unit 6 can be refracted by the microstructures 4 to increase its diffusion. The light path in the layer 3 can excite more of the quantum dots 31 and effectively improve the conversion efficiency of green light and red light. In other words, by generating more green light and red light, the intensity ratio of blue, green, and red light can be adjusted, thereby expanding the coordinates of the three primary colors of blue, green, and red in the chromaticity diagram. The area of the triangle enclosed thereby achieves the purpose of wide color gamut, and the mixed white light does not show color deviation due to the strong or weak light intensity of one of the color lights. In addition, the microstructures 4 provided on the second substrate 2 can also mix the light to effectively reduce the total reflection caused by the light emitted from the surface of the light emitting surface 22, thereby increasing the overall light extraction rate.

Referring to FIG. 4, when the light-emitting device 7 of the present invention is applied as a backlight module, it can form a display 8 together with a panel 81. The panel 81 is located on the side of the light-emitting surface 22 of the second substrate 2 of the optical film 10 of the light-emitting device 7 and presents a predetermined image by generating an optical effect from the light emitted by the light-emitting device 7. The panel 81 includes polarizing plates, liquid crystals, alignment films, color filters and other structures. Since the detailed structure and material selection of the panel 81 are well-known to those in the art and can be implemented in accordance with the prior art, no more details will be added here. Go into details. The display 8 effectively increases the color gamut range through the setting of the light-emitting device 1, thereby realizing high-quality color effects, so that the colors presented by the wide color gamut display 8 are richer and more vivid, and Can greatly enhance the user's visual experience.

To sum up, in the present invention, the microstructures 4 are arranged on the light incident surface 12 of the first substrate 1 of the optical film 10, and a light-emitting device 7 is formed together with a light-emitting unit 6, so that the light-emitting unit The first color light λ ₁ emitted by 6 passes through the microstructures 4 to change the path of the incident light, and then excites more of the quantum dots 31 in the diffusion layer 3 to make blue, green, and red light The mixed white light achieves a wide color gamut, and the microstructures 4 formed on the light-emitting surface 22 of the second substrate 2 can reduce the total reflection phenomenon caused by the light-emitting surface 22; the light-emitting device 7 can not only satisfy the market It can also be applied to the backlight module of the lighting industry and displays, so that the display 8 with the light-emitting device 7 can achieve higher-quality color effects, meet the needs of consumers, and promote and expand the market. The scale can indeed achieve the purpose of the present invention.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to This invention patent covers the scope.

10‧‧‧Optical film 1‧‧‧First substrate 11‧‧‧First side 12‧‧‧Glossy surface 2‧‧‧Second substrate 21‧‧‧Second surface 22‧‧‧Emitting surface 3 ‧‧‧Diffusion layer 31‧‧‧Quantum dot 4‧‧‧Microstructure 5‧‧‧Bottom groove 6‧‧‧Light-emitting unit 7‧‧‧Light-emitting device8‧‧‧Display 81‧‧‧Panel H‧‧‧ Height P‧‧‧Vertex R‧‧‧Radius of curvature W‧‧‧Array spacing λ1‧‧‧First color light

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: FIG. 1 is a schematic top view illustrating a first embodiment of the optical film of the present invention; FIG. 2 is along the line of FIG. 1 A schematic cross-sectional view taken by line II-II to assist in explaining the first embodiment of the optical film of the present invention; FIG. 3 is a schematic cross-sectional view illustrating a light-emitting device with the optical film of the present invention; and FIG. 4 is a diagram The partial schematic diagram illustrates a display with the light-emitting device of the present invention.

10‧‧‧Optical film

1‧‧‧First substrate

11‧‧‧The first side

12‧‧‧Glossy surface

2‧‧‧Second base material

21‧‧‧Second side

22‧‧‧Glossy surface

31‧‧‧Quantum Dot

4‧‧‧Microstructure

5‧‧‧Bottom groove

H‧‧‧Height

P‧‧‧Vertex

R‧‧‧Radius of curvature

W‧‧‧Array pitch

3‧‧‧Diffusion layer

Claims (10)

An optical film capable of exciting a second color light having a wavelength greater than that of the first color light after a first color light enters the optical film, the optical film comprising: a first substrate including a first surface , And a light-incident surface opposite to the first surface; a second substrate, spaced apart from the first substrate, and including a second surface facing the first surface, and a second surface opposite to the second surface The light-emitting surface; a diffusion layer located between the first substrate and the second substrate and includes a plurality of quantum dots; a plurality of microstructures are formed in close proximity to the light-incident surface of the first substrate ; And a plurality of bottom grooves, surrounding the microstructures, two adjacent parallel bottom grooves have an array spacing W, and each microstructure has a vertex P located at the geometric center, and a light incident The height H from the surface to the vertex P, and the aspect ratio between the height H and the array pitch W is between 3% and 60%; wherein, the first color light can pass through the light incident surface of the first substrate The diffusion layer is emitted from the light-emitting surface of the second substrate, and the first color light can excite the quantum dots to emit the second color light. The optical film according to claim 1, wherein the microstructures are further formed on the light-emitting surface of the second substrate. The optical film according to claim 1 or 2, wherein the shape of the microstructures is one of a semicircle, a cone, and an irregular shape. The optical film according to claim 3, wherein the microstructures are microlenses that protrude away from the diffusion layer and are generally semicircular, cone-shaped, and irregular. The optical film according to claim 1, wherein each bottom groove has a radius of curvature R, and the radius of curvature R is between 1.0 μm and 7.0 μm. The optical film according to claim 5, wherein the array pitch W is between 6.0 μm and 60 μm. The optical film of claim 6, wherein the height H of each microstructure is between 1.0 and 40 μm. The optical film according to claim 1, wherein the first color light can also excite the quantum dots to emit a third color light having a wavelength greater than that of the second color light, the first color light is blue light, and the second color light The color light is green light, and the third color light is red light. A light-emitting device, comprising: an optical film according to claim 1; and a light-emitting unit located on the side of the light-incident surface of the first substrate of the optical film and capable of emitting a first color light, the The first color light can enter the diffusion layer from the light incident surface of the first substrate through the microstructures, and is emitted from the light exit surface of the second substrate, and the first color light can excite the The quantum dot emits a second color light with a wavelength greater than that of the first color light. A display, comprising: a light-emitting device according to claim 9; and a panel located on the side of the light-emitting surface of the second substrate of the optical film of the light-emitting device and emitted by the light-emitting device The light produces an optical effect to present a predetermined image.

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