WO2015081692A1

WO2015081692A1 - Light guide plate, backlight source and liquid crystal display apparatus

Info

Publication number: WO2015081692A1
Application number: PCT/CN2014/080847
Authority: WO
Inventors: 赵洪宇; 王丹; 邹斌; 吕金库; 郭俊杰
Original assignee: 京东方科技集团股份有限公司; 北京京东方显示技术有限公司
Priority date: 2013-12-06
Filing date: 2014-06-26
Publication date: 2015-06-11
Also published as: CN103676315A

Abstract

A light guide plate, a backlight source and a liquid crystal display apparatus relate to the technical field of display. The light guide plate (1) comprises a substrate (10) and a blue light-excited light emitting layer (11) that is located on an in-light surface of the substrate (10). The backlight source of the liquid crystal display apparatus comprises the light guide plate (1) and a blue light emitting device (2). Light emitted by the blue light emitting component directs to the blue light-excited light emitting layer (11) and excites the blue light-excited light emitting layer (11), which can improve a display color gamut of the liquid crystal display apparatus, and thus improve display quality of the liquid crystal display apparatus.

Description

Light guide plate, backlight and liquid crystal display device

The present invention relates to the field of display technologies, and in particular, to a light guide plate, a backlight, and a liquid crystal display device. Background technique

The liquid crystal display device is a flat panel display device which works by utilizing a liquid crystal material to modulate light under an electric field to produce various brightness and color changes to form an image. Since the liquid crystal material itself does not emit light, the liquid crystal display device requires a special backlight. The display performance metrics of liquid crystal display devices include contrast, color gamut, etc. An important factor affecting the color gamut of existing liquid crystal display devices is backlight technology.

With the development of liquid crystal display technology, people have higher and higher requirements for color display of liquid crystal display devices. The color gamut of existing liquid crystal display devices is relatively low, and it is difficult to achieve more than 80%, which leads to the display quality of liquid crystal display devices. Poor. Summary of the invention

The invention provides a light guide plate, a backlight and a liquid crystal display device for improving the color gamut of the liquid crystal display device, thereby improving the quality of the display image.

A light guide plate provided by an embodiment of the invention includes a substrate, and a blue light-emitting layer on the light incident surface of the substrate.

When the backlight of the liquid crystal display device comprises the light guide plate and the blue light emitting device according to the embodiment of the invention, the light emitted by the blue light emitting device emits the blue light of the light guide plate to excite the light emitting layer and excite the light emitting layer, so that the light entering the light guide plate has a relatively high light. The wide color gamut makes the display color of the liquid crystal display device more vivid, thereby improving the display quality of the liquid crystal display device.

According to an embodiment of the invention, the blue excitation light-emitting layer is a quantum dot material layer, a fluorescent material layer or a rare earth ion material layer.

Further, the blue light-emitting layer is a quantum dot material layer. The quantum dot material may be, for example, a semiconductor cluster having a size of 1 to 20 nm. Since the quantum dot material can withstand repeated excitations and has high luminous efficiency, the display quality of the liquid crystal display device can be effectively improved.

The light guide plate may further include a protective layer on a surface of the quantum dot material layer. Providing a protective layer on the quantum dot material layer can effectively prevent the quantum dot material layer from being degraded by moisture The fluorescence excitation effect of the sub-points improves the stability of the display quality of the liquid crystal display device.

According to an embodiment of the invention, the quantum dot material of the quantum dot material layer is a nanocrystal comprising indium phosphide and a pot.

According to an embodiment of the invention, the light incident surface of the substrate comprises a plurality of recessed structures. The plurality of recessed structures can scatter light entering the light guide plate, thereby greatly improving the uniformity of light entering the light guide plate, thereby further improving the display quality of the liquid crystal display device.

According to an embodiment of the invention, the blue excitation light-emitting layer is a coating layer or a coating layer.

According to an embodiment of the invention, the inside of the substrate has a bubble structure, and the bubble structure has a diameter of less than 0.1 mm. The bubble structure can sufficiently scatter the light entering the inside of the light guide plate, further improving the uniformity of the light, thereby effectively improving the display quality of the liquid crystal display device.

According to the embodiment of the present invention, the light-emitting surface of the substrate may have a prism structure, which can effectively improve the brightness of the light-emitting surface of the light guide plate, thereby improving the display brightness and thereby improving the display quality of the liquid crystal display device.

According to an embodiment of the present invention, the light guide plate further includes a semi-transmissive film layer on a light-emitting surface of the substrate, and the semi-transparent film layer has the same polarization direction as the lower polarizer of the liquid crystal panel. The semi-transflective film layer located on the light-emitting surface of the substrate can effectively improve the optical utilization efficiency, thereby improving the display quality of the liquid crystal display device. According to an embodiment of the present invention, there is provided a backlight, comprising: a light source, and the light guide plate according to any one of the foregoing aspects, wherein the light source comprises a plurality of blue light emitting devices, and the light emitted by the blue light emitting device emits The luminescent layer is excited to the blue light of the light guide plate. Since the above-mentioned light guide plate has the above technical effects, the backlight having the light guide plate also has a corresponding technical effect.

According to an embodiment of the invention, the blue light emitting device is a blue light emitting diode emitting light having a wavelength of 420 nm to 450 nm.

According to an embodiment of the present invention, there is also provided a liquid crystal display device comprising the backlight of the foregoing technical scheme. Since the backlight described above has the above-described technical effects, the liquid crystal display device having the backlight has a corresponding technical effect. DRAWINGS

1 is a cross-sectional structural view showing a first embodiment of a light guide plate of the present invention;

2 is a cross-sectional structural view showing a first embodiment of a light guide plate of the present invention;

3 is a cross-sectional structural view showing a first embodiment of a light guide plate of the present invention; 4 is a cross-sectional structural view showing a fourth embodiment of a light guide plate of the present invention;

Figure 5 is a cross-sectional structural view showing a fifth embodiment of the light guide plate of the present invention;

Figure 6 is a cross-sectional structural view showing a sixth embodiment of the light guide plate of the present invention;

7 is a cross-sectional structural view showing an embodiment of a backlight of the present invention;

FIG. 8 is a cross-sectional structural view showing an embodiment of a liquid crystal display device of the present invention.

Reference mark:

10-substrate 11-blue light excitation layer 12-protective layer

13-bubble structure 15-semi-trans-permeable membrane layer 1-light guide plate

2-blue light emitting device 4-lower polarizer

In order to improve the display quality of the liquid crystal display device, embodiments of the present invention provide a light guide plate, a backlight, and a liquid crystal display device. Compared with the prior art, the light guide plate comprises a substrate and a blue excitation light emitting layer located on the light incident surface of the substrate. When the light guide plate is applied to the backlight, the light emitted by the blue light emitting device emits light to the blue light excitation layer and excites the blue light to emit light. The layer allows the light entering the light guide plate to have a wider color gamut, thereby making the color gamut of the liquid crystal display device wider, thereby improving the display quality of the liquid crystal display device.

The invention will now be described in detail by way of specific embodiments with reference to the accompanying drawings. While the exemplary embodiments of the invention are illustrated in the drawings, the invention may be embodied in a variety of different forms and should not be construed as being limited to the embodiments described herein.

For ease of description, spatially relative terms such as "under", "lower", "above", "upper", etc. may be used herein to describe one element or component as shown in the figure. The relationship between one or some of the elements or components. It will be understood that the spatially relative terms are used to summarize the different orientations of the device in use or operation, including the orientation shown in the drawings. For example, if the device in the drawings In the above, the elements "under" or "below" other elements or components will be "above" or "above" other components or components. Thus, the exemplary term "is in . . . The following can cover both the top and bottom orientations. The device can take other orientations (eg, rotated 90 degrees or in other orientations), and the spatial relativity descriptors used at this time are interpreted accordingly.

As shown in FIG. 1, the light guide plate provided by the embodiment of the present invention includes: a substrate 10, and a blue light-emitting layer 11 on the light incident surface of the substrate 10. In the three primary colors of visible light of the human eye, since the wavelength of the blue light is short and the energy is large, in the embodiment of the present invention, blue light can be used as the excitation light source. In the embodiments of the present invention, the light incident surface of the substrate 10 is a surface opposite to the position of the light source, such as the lower surface of the substrate, and the light emitting surface of the substrate 10 is, for example, the upper surface of the substrate.

The material of the substrate 10 is not limited, and may be, for example, PMMA (Polymethyl Methacrylate, polymethyl methacrylate, PMMA for short); the blue light-emitting layer 11 may be a coating layer, that is, a light-incident surface coated on the substrate 10, or may be The coating layer is coated on the light incident surface of the substrate 10; the blue light excitation light emitting layer 11 has a plurality of specific forms, and may be a quantum dot material layer, a fluorescent material layer or a rare earth ion material layer. The quantum dot material may be, for example, a semiconductor cluster having a size of 1 to 20 nm. Since the quantum dot material can be subjected to repeated multiple excitations and has high luminous efficiency, and the color gamut of the fluorescent emission of the quantum dot material can be improved by changing the size and chemical composition of the quantum dot material, the present invention preferably uses a quantum dot material. The layer acts as a blue light excitation light emitting layer, which can effectively improve the display quality of the liquid crystal display device.

There are a variety of quantum dot materials for the blue dot excited quantum dot material layer, and the specific materials used can be selected according to the actual application and needs. For example, according to an embodiment of the present invention, the quantum dot material of the quantum dot material layer may be a nanocrystal including indium phosphide and cadmium.

Referring to FIG. 7, when the light guide plate provided by the embodiment of the present invention is applied to a backlight, the light source of the backlight is provided by the blue light emitting device 2, and the light emitted by the blue light emitting device 2 is directed to the blue light excitation layer 11 to excite the blue light excitation. Light emitting layer 11. When the quantum dot material layer is used as the blue excitation light-emitting layer, the peak of the radiation-emitting spectrum curve of the quantum dot material is narrow, and the energy can be controlled to be concentrated in the RGB portion, so that the color of the light emitted from the blue-light-emitting layer is saturated. The high degree of RGB monochromatic light has a high brightness, that is, closer to the edge on the CIE map, so that the RGB three-point coordinates define a larger range. Since the colors in this range can be added by the three colors of light, the color gamut becomes wider. Therefore, the light entering the light guide plate 1 has a wider color gamut, so that the color gamut of the liquid crystal display device is wider and the display color is more vivid, thereby improving the display quality of the liquid crystal display device.

When the blue light-emitting layer 11 is a quantum dot material layer, as shown in FIG. 3, the light guide plate of the third embodiment of the present invention further includes: a protective layer 12 on the surface of the quantum dot material layer.

The protective layer is disposed on the quantum dot material layer, which can effectively prevent the quantum dot material layer from deteriorating the fluorescence excitation effect of the quantum dots, thereby improving the quality of the light guide plate and improving the display quality stability of the liquid crystal display device.

The second embodiment as shown in Fig. 2 provides an improved light guide plate in which the light incident surface of the substrate 10 includes a plurality of recessed structures. The plurality of recessed structures can scatter light entering the light guide plate, thereby greatly improving the uniformity of the brightness of the light entering the light guide plate, and further improving the light guide plate including the light guide plate The display quality of the liquid crystal display device. The substrate 10 including a plurality of recessed structures may be formed by one-shot molding or hot press molding.

In order to further improve the uniformity of the brightness of the light entering the light guide plate, as shown in the fourth embodiment shown in FIG. 4, the inside of the substrate 10 has a bubble structure 13 to sufficiently scatter the light entering the inside of the light guide plate to further improve the uniformity of the light. Therefore, the display quality of the liquid crystal display device is effectively improved. The diameter of the bubble structure 13 can be, for example, less than 0.1 mm. By making the diameter of the bubble structure within this range, the picture quality can be substantially prevented, thereby preventing the display quality of the liquid crystal display device from being lowered by the addition of the bubble structure.

Of course, the above embodiment is a preferred embodiment of the present invention. The bubble structure inside the substrate 10 of the present invention may be replaced by other material particles different from the refractive index of the substrate 10, such as quartz glass particles or polycarbonate particles.

As shown in FIG. 5, and referring to FIG. 8, the light guide plate provided by the fifth embodiment of the present invention further includes a semi-transflective film layer 15 on the light-emitting surface of the substrate 10, a semi-transflective film layer 15 and a liquid crystal panel. The polarization directions of the lower polarizers 4 are the same.

A semi-transparent film layer is disposed on the light-emitting surface of the substrate, and the polarization direction thereof is the same as the polarization direction of the lower polarizer of the liquid crystal panel. Therefore, when only the polarization direction of the light is the same as the polarization direction of the semi-transmissive film layer, the light is It is only possible to shoot the downward polarizer through the semi-transparent film. When the light enters the inside of the light guide plate and the downward polarizer is emitted from the light exit surface of the light guide plate, the light having a polarization direction different from that of the lower polarizer cannot pass through the semi-transparent film layer, and the semi-transparent film layer can be impenetrable. The light is reflected back to the inside of the light guide plate for recycling, thereby improving the optical utilization rate and improving the display quality of the liquid crystal display device.

Further, the semi-transmissive film layer re-reflects the impenetrable light back into the interior of the light guide plate and interacts with the bubble structure inside the substrate, so that the light inside the light guide plate is more uniform, thereby improving the display quality of the liquid crystal display device.

The semi-transparent film layer 15 can be applied to the light-emitting surface of the substrate 10, and the material of the transflective film layer 15 is not limited. In this embodiment, PET (Polyethylene terephthalate, polyethylene terephthalate, Referred to as PET).

Further, in order to further improve the display quality of the liquid crystal display device, as shown in FIG. 6, in the light guide plate provided by the sixth embodiment of the present invention, the light-emitting surface of the substrate 10 has a prism structure, which can effectively improve the light-emitting surface of the light guide plate. Brightness.

Based on the light guide plate provided in the above embodiments, the embodiment of the present invention further provides a backlight, the backlight includes: a light source, and the light guide plate provided by any of the foregoing embodiments, where the light source includes A plurality of blue light emitting devices, the light emitted by the blue light emitting device emits blue light from the light guide plate to excite the light emitting layer.

As shown in FIG. 7, a preferred embodiment of the present invention provides a direct type backlight, comprising: a light source, and the light guide plate 1 provided by any of the foregoing embodiments, the light source comprises a plurality of blue light emitting devices 2, and the blue light emitting device 2 The emitted light is directed toward the blue light to excite the light-emitting layer 11. The light guide plate 1 includes: a substrate 10, a blue light excitation light emitting layer 11 on the light incident surface of the substrate 10 (the blue light excitation light emitting layer 11 is, for example, a quantum dot material layer), a protective layer 12 on the surface of the quantum dot material layer, and a substrate The inside of 10 has a bubble structure 13 having a diameter of 0.05 mm, a semi-transmissive film layer 15 on the light-emitting surface of the substrate 10, and a polarization of the semi-transparent film layer 15 and the lower polarizer 4 of the liquid crystal panel (see Fig. 8). The same direction. The light incident surface of the substrate 10 includes a plurality of recessed structures, and the light emitting surface of the substrate 10 has a prism structure. Since the backlight is the light guide plate of the above embodiment, the color gamut of the liquid crystal display device can be improved, and the display quality of the liquid crystal display device can be improved.

Optionally, the light guide plate, the upper prism layer, the lower prism layer and the diffusion sheet may be integrated into an integrated component, so that the integrated component itself has the function of collecting and diffusing light, and is convenient for production and assembly of the backlight. The product defects caused by the assembly of the diaphragm are avoided, and the assembly efficiency is greatly improved, thereby effectively reducing the cost of the backlight. The upper prism layer, the lower prism layer and the diffusion sheet may comprise any form well known to those skilled in the art.

As a preferred embodiment of the backlight of the present invention, the blue light-emitting device 2 is a blue light-emitting diode having a light wavelength of from 420 nm to 450 nm. The blue light emitted by the blue light emitting diode with a wavelength of 420 nm to 450 nm can excite quantum dot materials including indium phosphide and cadmium, thereby further increasing the color gamut of the liquid crystal display device and thereby improving the display quality of the liquid crystal display device. The blue light emitting device 2 can be selected according to specific applications and actual needs. For example, the blue light emitting device 2 can be a blue light emitting diode emitting light having a wavelength of 435 nm.

The present invention further provides a liquid crystal display device including the backlight provided by the above embodiment, which is the same as the above embodiment. The backlight in the medium, so the beneficial effects of the liquid crystal display device, please refer to the above embodiment. The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the inventions

Claims

Rights request

I. A light guide plate, characterized in that it includes: a substrate, and a blue light excitation luminescent layer located on the light incident surface of the substrate.

2. The light guide plate according to claim 1, characterized in that the blue light excitation luminescent layer is a fluorescent material layer or a rare earth ion material layer.

3. The light guide plate according to claim 1, characterized in that the blue light excitation luminescent layer is a quantum dot material layer.

4. The light guide plate of claim 3, further comprising a protective layer located on the surface of the quantum dot material layer.

5. The light guide plate according to claim 3, wherein the quantum dot material of the quantum dot material layer is a nanocrystal including indium phosphide and cadmium.

6. The light guide plate according to claim 1, wherein the light incident surface of the substrate includes a plurality of recessed structures.

7. The light guide plate according to claim 1, characterized in that the blue light excitation luminescent layer is a coating layer or a coating layer.

8. The light guide plate according to claim 1, wherein the substrate has a bubble structure inside, and the diameter of the bubble structure is less than 0.1 mm.

9. The light guide plate of claim 1, wherein the light exit surface of the substrate has a prism structure.

10. The light guide plate according to any one of claims 1 to 9, wherein the light guide plate further includes a semi-reflective and semi-permeable film layer located on the light exit surface of the substrate, and the semi-reflective and semi-permeable film layer The polarization direction of the layer is the same as that of the lower polarizer of the LCD panel.

II. A backlight, characterized in that it includes: a light source, and the light guide plate according to any one of claims 1 to 10, wherein the light source includes a plurality of blue light emitting devices, and the blue light emitting device The blue light emitted from the light guide plate excites the luminescent layer.

12. The backlight of claim 11, wherein the blue light-emitting device is a blue light-emitting diode that emits light with a wavelength of 420 nanometers to 450 nanometers.

13. A liquid crystal display device, characterized by comprising the backlight of claim 11 or 12.