TWI708100B - Optical device - Google Patents

Abstract

The invention discloses an optical device including a wavelength-converting film, a transparent lower barrier film, a transparent upper barrier film and a translucent film. The wavelength-converting film includes a transparent substrate and a plurality of quantum dots uniformly dispersed in the transparent substrate. The transparent lower barrier film is bonded on a lower surface of the wavelength-converting film. The transparent upper barrier film is bonded on an upper surface of the wavelength-converting film. A top surface of the transparent barrier film thereon defines a display region and an edge region surrounding the display region. The translucent film is formed on the top surface of the transparent barrier film and overlays only the edge region. A reflectivity of the transparent barrier film is in a range of from 40% to 80%.

Description

Optical element

The present invention relates to an optical element containing quantum dots for use in a liquid crystal display system, and particularly relates to an optical element that can reduce the influence of the original light leaking at the edge once the quantum dot failure occurs in the edge area.

As everyone knows, the liquid crystal display system uses a liquid crystal panel to display images. However, the liquid crystal panel itself does not emit light, and a so-called backlight device must be used to achieve the light-emitting function. Therefore, the backlight device is an important component of the liquid crystal display device. Optical components with wavelength conversion function are important components of backlight devices.

A typical liquid crystal display system includes a combination of a backlight device and a liquid crystal display panel. A typical edge-lit backlight device usually includes multiple optical films (e.g., film, diffuser, etc.), optical elements with wavelength conversion function, light guide plate, reflective plate, light source, and external structures (e.g., frame, etc.) Constituted. A typical direct-lit backlight device does not require components such as light guide plates and reflectors. A typical liquid crystal display panel assembly includes two glass substrates and has liquid crystal material injected between the two glass substrates. In the assembling process of the liquid crystal display device, the backlight device and the liquid crystal display panel assembly need to be connected to the edges by the connecting member, so that the backlight device and the liquid crystal display panel assembly are stacked and fixed together.

At present, the optical element with wavelength conversion function of the existing backlight device uses quantum dots to improve the display quality. Quantum dots are semiconductors in the form of nanocrystals, which can provide alternative displays. The electronic properties of quantum dots are usually determined by the size and shape of the nanocrystal. Quantum dots of the same material, but with different sizes, can emit light of different colors when excited. More specifically, the amount The wavelength of light emitted by the sub-dots varies with the size and shape of the quantum dots. In one example, larger quantum dots can emit longer wavelength light (for example, red light), and smaller quantum dots can emit shorter wavelength light (for example, blue or violet light). For example, the quantum dots formed by cadmium selenide (CdSe) can be gradually adjusted, from a quantum dot with a diameter of 5 nm emitting in the red region of the visible spectrum to a quantum dot with a diameter of 1.5 nm emitting a purple region. By changing the size of quantum dots, the entire visible light wavelength can be emitted from a wavelength of about 460nm (blue light) to a wavelength of about 650nm (red light). The application of quantum dot technology to liquid crystal display systems can greatly improve the color gamut and color vividness of the liquid crystal display system, and reduce energy consumption.

Regarding the prior art of backlight devices using quantum dots, some of the prior art joins a wavelength conversion film containing quantum dots on a lower diffusion sheet among multiple optical films. Here, the wavelength conversion film needs upper and lower transparent gas barrier films to prevent the wavelength conversion film from contacting air.

There is also a prior art bonding a wavelength conversion film containing quantum dots on the light emitting surface of the light guide plate. Here, the wavelength conversion film also needs upper and lower transparent gas barrier films to prevent the wavelength conversion film from contacting air. In addition, the upper and lower transparent gas barrier films need to be coated with diffusing particles to avoid adsorption with the light guide plate and the lamella, which will increase the material cost.

Obviously, the prior art using a wavelength conversion film containing quantum dots requires matching upper and lower transparent gas barrier films.

It should be emphasized that even if the upper and lower transparent gas barrier films have been joined, over time, the edges of the wavelength conversion film will still be attacked by air and cause the quantum dots to fail. Considering that the current liquid crystal display system has a trend toward a narrow frame, that is, the shielding area of the peripheral edge of the liquid crystal display panel assembly is small. Once the quantum dot failure occurs at the edge of the wavelength conversion film, the original light emitted from the light source will leak from the edge of the backlight device, which will affect the uniformity of the color coordinate and the picture quality of the liquid crystal display system. However, the size of the failure area at the edge of the wavelength conversion film depends on the environmental conditions (for example, humidity) and cannot Clearly defined in advance, the current optical components using quantum dots do not have a better solution to the failure of quantum dots in the edge area.

In addition, the light from the edge area of the optical element using quantum dots is not actually used. At present, optical components using quantum dots have no solution to recycle the unused light in the edge area.

Therefore, one of the technical problems to be solved by the present invention is to provide an optical element containing quantum dots for use in a liquid crystal display system. The optical element according to the present invention can reduce the influence of light leakage of original light at the edge once the quantum dot failure occurs in the edge area of the optical element. In addition, the optical element according to the present invention can recycle part of the unused light in the edge area.

The optical element according to a preferred embodiment of the present invention includes a wavelength conversion film, a transparent lower gas barrier film, a transparent upper gas barrier film, and a light-transmitting film. The wavelength conversion film has an upper surface and a lower surface. The wavelength conversion film includes a transparent substrate and a plurality of first quantum dots. The plurality of first quantum dots are uniformly distributed in the transparent substrate. The transparent lower gas barrier film is bonded to the lower surface of the wavelength conversion film. The transparent upper gas barrier film is bonded to the upper surface of the wavelength conversion film and has a top surface. The top surface of the transparent upper gas barrier film defines the first display area and the edge area thereon. The edge area surrounds the first display area. The light-transmitting film is formed on the top surface of the transparent upper gas barrier film and only covers the edge area. The range of reflectance of light-transmitting film is 40%~80%. When the first color light is emitted from below the transparent lower gas barrier film to the optical element according to the present invention, the first part of the first color light is converted into the second color light by a plurality of first quantum dots, and the second color light passes through the transparent On the gas barrier film. The rest of the light of the first color is emitted from the top surface of the transparent upper gas barrier film and mixed with the light of the second color to form the light of the third color.

In a specific embodiment, the optical element according to the present invention is assembled in a liquid crystal display system. The liquid crystal display system includes an inner frame and defines The second display area. The area of the second display area of the liquid crystal display system is equal to or greater than the area of the first display area on the top surface of the transparent upper gas barrier film.

In a specific embodiment, the wavelength conversion film further includes a plurality of second quantum dots. The plurality of second quantum dots are uniformly distributed in the transparent substrate. The second part of the first color light is converted into a fourth color light by a plurality of second quantum dots, and the fourth color light passes through the transparent upper gas barrier film. The rest of the light of the first color is emitted from the top surface of the transparent upper gas barrier film, and mixed with the second color light and the fourth color light to form the fifth color light.

In a specific embodiment, the range of the first refractive index of the transparent substrate is 1.46-1.50. The range of the second refractive index of the transparent gas barrier film is 1.55~1.65. The third refractive index of the transparent upper gas barrier film ranges from 1.55 to 1.65.

In a specific embodiment, the light-transmitting film may be formed of light-colored ink.

Furthermore, the optical element according to the present invention further includes a plurality of scattering particles. The scattering particles are uniformly distributed in the transparent film. In a specific embodiment, the plurality of scattering particles include a plurality of titanium dioxide particles, a plurality of barium sulfate particles, or a plurality of calcium sulfate particles.

Furthermore, the optical element according to the present invention further includes a plurality of fluorescent particles. The fluorescent particles are uniformly distributed in the light-transmitting film. The third part of the light of the first color is converted into the sixth color of light through a plurality of fluorescent particles through the light-transmitting film. The sixth colored light is mixed with the unconverted third portion of the first colored light to form the seventh colored light.

Different from the prior art, the optical element according to the present invention can reduce the influence of the original light leakage at the edge once the quantum dot failure occurs in the edge area of the optical element. In addition, the optical element according to the present invention can recycle part of the unused light in the edge area.

The advantages and spirit of the present invention can be further understood from the following detailed description of the invention and the accompanying drawings.

1‧‧‧Optical components

10‧‧‧Wavelength conversion film

102‧‧‧Upper surface

104‧‧‧Lower surface

106‧‧‧Transparent substrate

108‧‧‧First quantum dot

109‧‧‧Second quantum dot

12‧‧‧Transparent lower gas barrier film

14‧‧‧Transparent upper gas barrier film

142‧‧‧Top surface

144‧‧‧First display area

146‧‧‧Edge area

16‧‧‧Transparent film

17‧‧‧Scattering particles

18‧‧‧Fluorescent particles

2‧‧‧LCD display system

22‧‧‧LCD panel combination

222‧‧‧Second display area

24‧‧‧Inner frame

26‧‧‧Light guide plate

28‧‧‧Reflector

L1‧‧‧First color light

L1a‧‧‧The first part of the light

L1b‧‧‧Second light

L1c‧‧‧The third part of the light

L2‧‧‧Second color light

L3‧‧‧Third color light

L4‧‧‧The fourth color light

L5‧‧‧Fifth color light

L6‧‧‧Sixth color light

L7‧‧‧Seventh color light

Fig. 1 is an external view of an optical element according to a preferred embodiment of the present invention.

Fig. 2 is a cross-sectional view of the optical element in Fig. 1 along the line A-A.

Fig. 3 is a top view of a transparent upper gas barrier film, an essential element of an optical element according to a preferred embodiment of the present invention.

Fig. 4 is another cross-sectional view of the optical element in Fig. 1 along the line A-A.

Fig. 5 is another cross-sectional view of the optical element in Fig. 1 along the line A-A.

Please refer to FIGS. 1 to 4, which schematically illustrate an optical element 1 according to a preferred embodiment of the present invention. Fig. 1 is an external view of an optical element 1 according to a preferred embodiment of the present invention. 2 is a cross-sectional view of the optical element 1 in FIG. 1 along the line A-A, to schematically illustrate the structure of the optical element 1 according to a preferred embodiment of the present invention. FIG. 3 is a top view of a transparent upper gas barrier film 14 which is an essential element of the optical element 1 according to a preferred embodiment of the present invention. 4 is another cross-sectional view of the optical element 1 in FIG. 1, and the liquid crystal display panel assembly 22 and the inner frame 24 of the liquid crystal display system 2 are also schematically shown in FIG. 4. 5 is another cross-sectional view of the optical element 1 in FIG. 1. The liquid crystal display panel assembly 22 and the inner frame 24 of the liquid crystal display system 2 are also schematically shown in FIG. 5.

As shown in FIGS. 1 to 5, the optical element 1 according to the present invention includes a wavelength conversion film 10, a transparent lower gas barrier film 12, a transparent upper gas barrier film 14 and a light-transmitting film 16.

The wavelength conversion film 10 has an upper surface 102 and a lower surface 104. The wavelength conversion film 10 includes a transparent substrate 106 and a plurality of first quantum dots 108. The plurality of first quantum dots 108 are uniformly distributed in the transparent substrate 106.

In a specific embodiment, the transparent substrate 106 may be formed of a polymer material such as ultraviolet curable resin, but it is not limited to this.

In a specific embodiment, the plurality of first quantum dots 108 may be composed of a first group II-VI compound, a first group III-V compound, a first group IV-VI compound, a first group IV compound, or a mixture of the foregoing compounds Formed.

In a specific embodiment, the first II-VI group compound forming the plurality of first quantum dots 108 used in the present invention can be made of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, SeCdZnSe, CdZnTe, SeCdZnSe, CdSZnSe, CdZnSe HgZnSTe or other II-VI group compounds are formed.

In a specific embodiment, the first group III-V compound forming the plurality of first quantum dots 108 used in the present invention can be made of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAS, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb or III-V group compounds.

In a specific embodiment, the first IV-VI group compound forming the plurality of first quantum dots 108 used in the present invention can be made of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe or other IV-VI group compounds.

In a specific embodiment, the first group IV compound forming the plurality of first quantum dots 108 used in the present invention may be formed of Si, Ge, SiC, SiGe or other group IV compounds.

The transparent lower gas barrier film 12 is bonded to the lower surface 104 of the wavelength conversion film 10.

The upper transparent gas barrier film 14 is bonded to the upper surface 102 of the wavelength conversion film 10 and has a top surface 142. As shown in FIG. 3, the top surface 142 of the transparent upper gas barrier film 14 defines a first display area 144 and an edge area 146 thereon. The edge area 146 surrounds the first display area 144.

In a specific embodiment, both the transparent upper gas barrier film 14 and the transparent lower gas barrier film 12 may be formed of a polymer material, for example, polyethylene terephthalate (PET), polyacrylate (polyacrylate), polystyrene, polyimide, polyacrylamide, polyethylene, polyvinyl, poly-diacetylene, Polyphenylene-vinylene (polyphenylene-vinylene), polypeptide (polypeptide), polysaccharide (polysaccharide), polysulfone (polysulfone), polypyrrole (polypyrrole), polyimidazole (polyimidazole), polythiophene (polythiophene), polyether polyether, epoxy, silica glass, silica gel, siloxane, polyphosphate, hydrogel, agarose agarose), cellulose, etc.

As shown in FIGS. 2 and 4, the light-transmitting film 16 is formed on the top surface 142 of the transparent upper gas barrier film 14 and only covers the edge area 146. In particular, the reflectivity of the light-transmitting film 16 ranges from 40% to 80%. Therefore, the light directed to the light-transmitting film 16 will be partially penetrated and partially reflected.

When the first color light L1 is directed toward the optical element 1 according to the present invention from below the transparent lower gas barrier film 12, the first part of the light L1a of the first color light L1 is converted into the second color light L2 by a plurality of first quantum dots 108 , The second color light L2 passes through the transparent upper gas barrier film 14. The first color light L1 is generally blue light. The remaining part of the first color light L1 is emitted from the top surface 142 of the transparent upper gas barrier film 14 and mixed with the second color light L2 to form the third color light L3. In practical applications, the third color light L3 may be white light, but it is not limited thereto. When the first quantum dot 108 corresponding to the edge region 146 has not failed, the first color light L1 directed to the transparent film 16 will be partially reflected to facilitate reuse. The light emitted from the light-transmitting film 16 is also the third color light L3, but its brightness is low. When the first quantum dot 108 corresponding to the edge region 146 fails, the first color light L1 directed to the light-transmitting film 16 will be partially reflected to facilitate reuse. The light emitted from the light-transmitting film 16 is the first color light L1, but its brightness is low to reduce the influence of the original light (the first color light L1) from leaking at the edge.

In a specific embodiment, as shown in FIG. 4, the optical element 1 according to the present invention is assembled in a liquid crystal display system 2. The liquid crystal display system 2 includes an inner frame 24 and a liquid crystal display panel assembly 22. The liquid crystal display panel assembly 22 defines a second display area 222. The area of the second display area 222 of the liquid crystal display panel assembly 22 is equal to or greater than the area of the first display area 144 of the top surface 142 of the transparent upper gas barrier film 14. In the example shown in FIG. 4, the area of the second display area 222 of the liquid crystal display panel assembly 22 is equal to the area of the first display area 144 of the top surface 142 of the upper transparent gas barrier film 14.

The light source, multiple optical films, etc. of the backlight device are not shown in FIG. 4. It should be emphasized that the optical element 1 according to the present invention can be assembled in an edge-lit backlight device, and the edge-lit backlight device must include a light guide plate 26. As shown in FIG. 4, the optical element 1 according to the present invention can be installed on the light guide plate. 26 above. It should be stated that the optical element 1 according to the present invention can also be arranged under the light guide plate 26. In FIG. 4, the reflective plate 28 is disposed under the light guide plate 26 to reflect light. The optical element 1 according to the present invention can also be assembled in a direct type In the backlight device, the direct type backlight device does not need a light guide plate. In a specific embodiment, the inner frame 24 may be made of a polymer material, but it is not limited thereto. The lower surface of the liquid crystal display panel assembly 22 can be attached to the inner frame 24.

In a specific embodiment, as shown in FIG. 5, the wavelength conversion film 10 further includes a plurality of second quantum dots 109. The plurality of second quantum dots 109 are uniformly distributed in the transparent substrate 106. The second partial light L1b of the first color light L1 is converted into a fourth color light L4 by a plurality of second quantum dots 109, and the fourth color light L4 passes through the transparent upper gas barrier film 14. The remaining part of the first color light L1 is emitted from the top surface 142 of the transparent upper gas barrier film 14 and mixed with the second color light L2 and the fourth color light L4 to form the fifth color light L5. The components in FIG. 5 with the same numbers as those in FIG. 4 have the same or similar structures and functions, so I won't repeat them here.

In a specific embodiment, similarly, the plurality of second quantum dots 109 may be composed of a second group II-VI compound, a second group III-V compound, a second group IV-VI compound, a second group IV compound, or the foregoing A mixture of compounds is formed.

In a specific embodiment, the first refractive index of the transparent substrate 106 ranges from 1.46 to 1.50. The range of the second refractive index of the transparent lower gas barrier film 12 is 1.55 to 1.65. The third refractive index of the transparent upper gas barrier film 14 ranges from 1.55 to 1.65.

In a specific embodiment, the light-transmitting film 16 may be formed of light-colored ink (for example, white ink).

Furthermore, the optical element 1 according to the present invention further includes a plurality of scattering particles 17. The scattering particles 17 are uniformly distributed in the transparent film 16. The scattering particles 17 are used to scatter light passing through the light-transmitting film 16.

In a specific embodiment, the plurality of scattering particles 17 may include a plurality of titanium dioxide particles, a plurality of barium sulfate particles, or a plurality of calcium sulfate particles.

Furthermore, the optical element 1 according to the present invention further includes a plurality of fluorescent particles 18, for example, yellow fluorescent particles, green fluorescent particles and the like. The fluorescent particles 18 are evenly distributed in the transparent film 16. The third part of the light L1c of the first color light L1 is converted into the sixth color light L6 through the light-transmitting film 16 through a plurality of fluorescent particles 18. The sixth color light L6 is mixed with the unconverted part of the third partial light L1c of the first color light L1 to form the seventh color light L7. When the first quantum dot 108 corresponding to the edge area 146 has not failed, the hue of the seventh color light L7 is close to the hue of the third color light L3 or the hue of the fifth color light L5. When the first quantum dot 108 corresponding to the edge area 146 fails, the first color light L1 passing through the transparent film 16 is converted to red light by a plurality of fluorescent particles 18, which can reduce the original light (first color light L1) The effect of light leakage at the edge.

Through the detailed description of the preferred embodiments, it is believed that the present invention is different from the prior art. The optical element according to the present invention can reduce the influence of light leakage of original light at the edge once the quantum dot failure occurs in the edge area of the optical element. In addition, the optical element according to the present invention can recycle part of the unused light in the edge area.

Based on the above detailed description of the preferred embodiments, it is hoped that the characteristics and spirit of the present invention can be described more clearly, rather than limiting the aspect of the present invention by the preferred embodiments disclosed above. On the contrary, its purpose is to cover various changes and equivalent arrangements within the scope of the patent for which the present invention is intended. Therefore, the aspect of the patent scope applied for by the present invention should be interpreted in the broadest way based on the above description, so as to cover all possible changes and equivalent arrangements.

1‧‧‧Optical components

10‧‧‧Wavelength conversion film

102‧‧‧Upper surface

104‧‧‧Lower surface

106‧‧‧Transparent substrate

108‧‧‧First quantum dot

109‧‧‧Second quantum dot

12‧‧‧Transparent lower gas barrier film

14‧‧‧Transparent upper gas barrier film

142‧‧‧Top surface

144‧‧‧First display area

146‧‧‧Edge area

16‧‧‧Transparent film

17‧‧‧Scattering particles

18‧‧‧Fluorescent particles

2‧‧‧LCD display system

22‧‧‧LCD panel combination

222‧‧‧Second display area

24‧‧‧Inner frame

26‧‧‧Light guide plate

28‧‧‧Reflector

L1‧‧‧First color light

L1a‧‧‧The first part of the light

L1c‧‧‧The third part of the light

L2‧‧‧Second color light

L3‧‧‧Third color light

L6‧‧‧Sixth color light

L7‧‧‧Seventh color light

Claims (8)

An optical element, comprising: a wavelength conversion film having an upper surface and a lower surface, the wavelength conversion film including a transparent substrate and a plurality of first quantum dots, the plurality of first quantum dots are uniformly distributed on the transparent In the substrate; a transparent lower gas barrier film is attached to the lower surface of the wavelength conversion film; a transparent upper gas barrier film is attached to the upper surface of the wavelength conversion film and has a top surface, the The top surface defines a first display area and an edge area thereon, the edge area surrounding the first display area; and a light-transmitting film formed on the top surface of the transparent upper gas barrier film and covering only the edge Area, the range of a reflectance of the light-transmitting film is 40%~80%; wherein when a first color light is directed to the optical element from below the transparent lower gas barrier film, the first color light is a second A part of the light is converted into a second color light by the plurality of first quantum dots, the second color light passes through the transparent upper gas barrier film, the rest of the first color light is emitted from the top surface of the transparent upper gas barrier film and Mixed with the second color light to form a third color light. The optical element according to claim 1, wherein the optical element is assembled in a liquid crystal display system, the liquid crystal display system includes an inner frame and defines a second display area, and the area of the second display area is equal to or greater than The area of the first display area. The optical element according to claim 2, wherein the wavelength conversion film further comprises a plurality of second quantum dots, and the plurality of second quantum dots are uniformly distributed in In the transparent substrate, a second part of the first color light is converted into a fourth color light by the plurality of second quantum dots, the fourth color light passes through the transparent upper gas barrier film, and the first color light is The rest of the light is emitted from the top surface of the transparent upper gas barrier film and mixed with the second color light and the fourth color light to form a fifth color light. The optical element according to claim 2, wherein the first refractive index of the transparent substrate is in the range of 1.46 to 1.50, the second refractive index of the transparent lower gas barrier film is in the range of 1.55 to 1.65, and the transparent upper The third refractive index of the gas barrier film ranges from 1.55 to 1.65. The optical element according to claim 2, wherein the light-transmitting film is formed of a light-colored ink. The optical element according to claim 5, further comprising a plurality of scattering particles, and the scattering particles are uniformly distributed in the light-transmitting film. The optical element according to claim 6, wherein the plurality of scattering particles comprise one selected from the group consisting of a plurality of titanium dioxide particles, a plurality of barium sulfate particles, and a plurality of calcium sulfate particles. The optical element according to claim 5, further comprising a plurality of fluorescent particles, the fluorescent particles are uniformly distributed in the light-transmitting film, and a third part of the first color light passes through the light-transmitting film. The plurality of fluorescent particles are converted into a sixth color light, and the sixth color light and the unconverted part of the third part of the first color light are mixed to form a seventh color light.

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