WO2013127212A1

WO2013127212A1 - Light guide panel, backlight module, and display device

Info

Publication number: WO2013127212A1
Application number: PCT/CN2012/085280
Authority: WO
Inventors: 李文波; 王庆江; 魏伟
Original assignee: 京东方科技集团股份有限公司
Priority date: 2012-02-28
Filing date: 2012-11-26
Publication date: 2013-09-06
Also published as: CN102628579A; CN102628579B

Abstract

A light guide panel comprises: a first transparent substrate (1-1), a second transparent substrate (1-2), and a polymer dispersed liquid crystal layer (1-3) between the two transparent substrates. A backlight module using the light guide panel and a display device. The light guide panel, the backlight module, and the display device have the improved light transmittance and evenness of display brightness, and are applicable to transparent display and adjustable-backlight technologies.

Description

Light guide plate, backlight module and display device

The present disclosure relates to the field of transparent display technologies, and in particular, to a light guide plate, a backlight module, and a display device. Background technique

In Liquid Crystal Display (LCD), the Back Light Unit (BLU) is very important. BLU is a kind of light source behind the LCD. Because the LCD itself does not emit light, the BLU's illumination effect will directly affect the visual effect of the LCD.

BLU generally includes: a light source, a light guide panel (LGP), a bottom reflector, an optical film, and structural members (backplane, frame, light bar, etc.). The LGP is disposed on a side of the LCD that receives incident light, the light source is disposed on a side of the light guide plate, and the reflective sheet is disposed outside the LGP for reflecting light. LGP converts the incident parallel light into planar light based on the principle of light scattering. The light emitted from the LGP is then diffused and polarized by the optical film, and the light is collected by the concentrating prism sheet in the optical film to adjust the light divergence angle. The desired surface light source is provided to the LCD. The LGP material in the ordinary BLU is transparent in itself. When the LGP is formed, different dots are printed on the bottom side, and the light is scattered when hitting the dots, thereby forming a uniform surface light source.

The transparent display LCD can be used for window display, etc., which utilizes external ambient light as the backlight of the LCD. Since the conventional LGP has a designed dot, it can improve the uniformity of light, but when the transparent display is realized, the display item is blurred, which greatly affects the transparent display effect. Summary of the invention

The present invention provides a light guide plate, a backlight module, and a display device which are suitable for transparent display and have high transmittance and high display uniformity.

The present disclosure provides a light guide plate comprising: a first transparent substrate, a second transparent substrate, and a polymer dispersed liquid crystal layer disposed between the two transparent substrates.

In one example, the polymer dispersed liquid crystal layer comprises a polymer matrix and nanoscale liquid crystal molecules distributed in the polymer matrix.

In one example, a first transparent electrode layer is disposed between the first transparent substrate and the polymer dispersed liquid crystal layer, and a second transparent substrate is disposed between the second transparent substrate and the polymer dispersed liquid crystal layer. Two transparent electrode layers.

In one example, the first transparent electrode layer includes a plurality of sub-electrodes.

The present disclosure provides a backlight module including the above light guide plate.

In one example, the backlight module further includes: a bottom reflective sheet disposed on a side of the light guide plate opposite to a light exiting direction, the bottom reflective sheet comprising: a third transparent substrate, A four transparent substrate and a polymer dispersed liquid crystal layer disposed between the two transparent substrates.

In one example, a third transparent electrode layer is disposed between the third transparent substrate and the polymer dispersed liquid crystal layer, and a fourth transparent layer is disposed between the fourth transparent substrate and the polymer dispersed liquid crystal layer. Electrode layer.

In one example, the third transparent electrode layer or the fourth transparent electrode layer includes a plurality of sub-electrodes.

In one example, the second transparent substrate and the third transparent substrate are the same substrate. The present disclosure also provides a display device including the above backlight module.

In one example, the substrate of the display panel and the first transparent substrate of the backlight module are the same substrate.

The light guide plate, the backlight module and the display device of the present disclosure use polymer dispersed liquid crystal, which not only improves the transmittance, but also improves the uniformity of display brightness, and is particularly suitable for transparent display and adjustable backlight technology. DRAWINGS

In order to more clearly illustrate the technical solutions of the present disclosure or the prior art, the following description of the technical solutions provided in the present disclosure or the drawings used in the prior art description will be briefly introduced. Obviously, the drawings in the following description Only some of the specific embodiments of the technical solutions of the present disclosure are illustrated, and those skilled in the art can obtain other drawings according to the drawings without any creative work.

1 is a schematic structural view of a light guide plate according to an embodiment of the present disclosure;

2a and 2b are schematic diagrams of the scattering state and the transparent state of the PDLC, respectively;

3a and 3b are schematic structural views of a backlight module according to an embodiment of the present disclosure. FIG. 4 is a schematic structural view of a display device according to an embodiment of the present disclosure. detailed description

The technical solutions in the embodiments of the present disclosure are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present disclosure. It is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without departing from the inventive scope are the scope of the disclosure.

The light guide plate, the backlight module and the display device proposed in the present disclosure are described in detail below with reference to the accompanying drawings and embodiments.

As shown in FIG. 1 , a light guide plate according to an embodiment of the present disclosure includes: a first transparent substrate 1-1, a second transparent substrate 1-2, and a polymer dispersed liquid crystal between two transparent substrates (Polymer Dispersed Liquid Crystal, PDLC) Layers 1-3. Among them, the PDLC includes a polymer matrix and nano-sized liquid crystal molecules dispersed in the polymer matrix. Such a light guide plate has a high transmittance. During the display process, light is scattered by the nano-scale liquid crystal molecules, and the point light source or the line light source is efficiently converted into a uniform surface light source to ensure uniformity of display. The PDLC light guide plate can also be applied to transparent display technology, and its transmittance is high, which has incomparable advantages compared with the conventional light guide plate.

According to the characteristics of the PDLC, in order to achieve the best display effect, the first transparent substrate 1-1 and

A first transparent electrode layer 1-4 is further disposed between the PDLC layers 1-3, and a second transparent electrode layer 1-5 is further disposed between the second transparent substrate 1-2 and the PDLC layer 1-3. The material of the first and second transparent electrode layers 1-4 and 1-5 is preferably ITO, but is not limited thereto. The PDLC layer in the unpowered region is in the off state, and the corresponding PDLC layer in the region is in a scattering state, and the incident light is scattered to achieve uniform light output, as shown in Fig. 2a. For the PDLC in the powered region, the PDLC is in an open state under the electric field, and the corresponding PDLC layer in the region is in a transparent state, as shown in Fig. 2b. Moreover, by controlling the electric field of the PDLC region, the effect of adjusting the density of the liquid crystal molecules scattering inside the PDLC can be achieved, so that the process error and the dot design error can be corrected in time to achieve the best display effect. Preferably, the first transparent electrode layer 1-4 or the second transparent electrode layer 1-5 includes a plurality of sub-electrodes, so that control of liquid crystal molecules in different regions in the PDLC layer can be achieved.

In addition to the above-mentioned driving method (that is, the arrangement of the transparent electrode layer), it is also possible to add a source matrix (preferably a thin film transistor (TFT)) between the transparent substrate and the PDLC, and realize by TFT. More granular partition control for PDLC.

The present disclosure also provides a backlight module including the above-mentioned light guide plate. As shown in FIG. 3a, the backlight module further includes: a bottom reflective sheet 2 disposed on a side of the light guide plate opposite to the light exiting direction, and the bottom reflective sheet 2 includes: a third transparent substrate 2-1, Fourth transparent substrate 2-2 And a PDLC layer 2-3 disposed between the third and fourth transparent substrates. Similarly, a third transparent electrode layer 2-4 is disposed between the third transparent substrate and the PDLC layer 2-3, and a fourth transparent electrode layer 2 is disposed between the fourth transparent substrate 2-2 and the PDLC layer 2-3. 5. Preferably, the fourth transparent electrode layer 2-5 includes a plurality of sub-electrodes to achieve control of liquid crystal molecules in different regions of the PDLC layer. Of course, other driving methods can also be selected as described above, and no mention is made here.

In this embodiment, the second transparent substrate 1-2 and the third transparent substrate 2-1 may be the same substrate, thereby reducing the process cost, as shown in FIG. 3b. After the first transparent substrate and the second transparent substrate of the light guide plate and the PDLC layer are completed, the bottom reflective sheet is directly processed on the back surface of the second transparent substrate of the light guide plate (ie, the second transparent substrate is the third transparent The substrate) can reduce one substrate, increase the transmittance, and reduce the process cost. At the same time, the defects caused by the adhesion of the third substrate of the bottom reflection sheet and the second substrate of the light guide plate are reduced, the product quality and the display quality are improved, and the integration of the light guide plate and the bottom reflection sheet is completed.

In addition, the present disclosure also provides a display device including the above backlight module. The display device can be any transmissive LCD that requires a backlight module, including a display device that requires transparent display, as shown in FIG. The display device is, for example, an adjustable backlight display device. The apparatus includes: a display panel 3, a backlight module of the present disclosure (the above-described: light guide plate 1 and bottom reflection sheet 2 are shown), and a display article area 4. The PDLC layer of the bottom reflection sheet 2 can be driven differently: when it is not powered, the PDLC layer is in a scattering state, and only the display content in the display panel 3 located in front of the backlight module can be seen at this time; When the power is on, the PDLC layer is in a transparent state. Under the action of ambient light, the display content of the display panel 3 located in front of the backlight module can be seen, and the backlight module can be clearly seen. The items displayed in the display item area 4 further improve the transmittance while switching between transparent and non-transparent display.

By performing targeted driving on the PDLC light guide plate, the uniformity of the brightness of the above display device can be further improved to achieve an optimal display effect.

The above-mentioned transparent substrate may be made of a transparent material such as glass.

For the PDLC light guide plate of the present disclosure, in order to prepare a PDLC containing nano-scale liquid crystal molecules, it can be achieved by aggravating the polymerization reaction between the polymer matrix and the liquid crystal molecules, for example, changing the polymerization reaction conditions or the dose of the reaction materials, etc., and will not be described herein. .

The preparation steps for other necessary components of the backlight are not mentioned here, nor should they be construed as limiting the disclosure.

The above embodiments are only intended to illustrate the present invention, and are not intended to limit the present invention. Various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention, and therefore all equivalent technical solutions are also within the scope of the present invention. The claims are limited.

Claims

Claim

I. A light guide plate, comprising: a first transparent substrate, a second transparent substrate, and a polymer dispersed liquid crystal layer disposed between the two transparent substrates.

The light guide plate according to claim 1, wherein the polymer dispersed liquid crystal layer comprises a polymer matrix and nano-sized liquid crystal molecules distributed in the polymer matrix.

The light guide plate according to claim 1 or 2, wherein a first transparent electrode layer is disposed between the first transparent substrate and the polymer liquid crystal layer, and the second transparent substrate is A second transparent electrode layer is disposed between the polymer liquid crystal layers.

The light guide plate according to any one of claims 1 to 3, wherein the first transparent electrode layer comprises a plurality of sub-electrodes.

A backlight module, comprising the light guide plate according to any one of claims 1 to 4.

The backlight module of claim 5, further comprising a bottom reflective sheet disposed on a side of the light guide plate opposite to a light exiting direction, the bottom reflective sheet comprising a third transparent substrate, a fourth transparent substrate, and a polymer liquid crystal layer disposed between the two transparent substrates.

The backlight module according to claim 5 or 6, wherein a third transparent electrode layer is disposed between the third transparent substrate and the polymer dispersed liquid crystal layer, and the fourth transparent substrate is A fourth transparent electrode layer is disposed between the polymer dispersed liquid crystal layers.

The backlight module according to claim 7, wherein the third transparent electrode layer or the fourth transparent electrode layer comprises a plurality of sub-electrodes.

The backlight module according to claim 6 or 7, wherein the third transparent substrate and the second transparent substrate are the same substrate.

A display device, comprising the backlight module of any one of claims 5-9.

The device according to claim 10, further comprising a display panel, wherein the substrate of the display panel and the first transparent substrate of the backlight module are the same substrate.