CN115755465A - Polarized light-emitting unit, light-emitting substrate, backlight module, display device and equipment - Google Patents

Abstract

Embodiments of the present disclosure provide a polarized light-emitting unit, a light-emitting substrate, a backlight module, a liquid crystal display device, and a VR display device, which belong to the field of display technology. The polarized light-emitting unit includes a light-emitting unit, a quarter-wave plate and a polarized reflective layer. Wherein, the light-emitting unit has a light-emitting surface; the quarter-wave plate is arranged on one side of the light-emitting surface of the light-emitting unit; the polarized reflection layer is arranged on the side of the quarter-wave plate away from the light-emitting surface. The liquid crystal display device based on the polarized light-emitting unit has higher light efficiency.

Description

Polarized light-emitting unit, light-emitting substrate, backlight module, display device and equipment

technical field

The present disclosure relates to the field of display technology, in particular, to a polarized light-emitting unit, a light-emitting substrate, a backlight module, a liquid crystal display device, and a VR display device.

Background technique

LED (Inorganic Light Emitting Diode) backlight modules are more and more widely used in liquid crystal display devices. FIG. 1 is a schematic structural diagram of a current liquid crystal display device; referring to FIG. 1 , the liquid crystal display device includes a liquid crystal display module LCM and a backlight module BLU that are laminated and matched. Wherein, the backlight module BLU includes a stacked lamp board LBP and optical film materials, these optical film materials generally include but not limited to filter A, multi-layer diffuser (such as the first diffuser DiffuserA and the second diffuser DiffuserB) , color conversion film TRF (such as fluorescent film or quantum dot film) and multi-layer brightness enhancement film (such as the first brightness enhancement film BEF1 and the second brightness enhancement film BEF2). The natural light (non-polarized light) emitted by the light board LBP is filtered by the optical film, diffused and mixed, color converted, and focused and brightened, and then irradiates the liquid crystal display module LCM in a non-polarized state. The liquid crystal display module LCM includes a first polarizer POLA, a liquid crystal display panel PNL and a second polarizer POLB stacked up to display images using the non-polarized backlight provided by the backlight module BLU.

It is necessary to further increase the light transmittance of the liquid crystal display device, so as to improve display brightness or reduce power consumption.

It should be noted that the information disclosed in the above background section is only for enhancing the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art.

Contents of the invention

The purpose of the present disclosure is to overcome the shortcomings of the above-mentioned prior art, provide a polarized light-emitting unit, a light-emitting substrate, a backlight module, a liquid crystal display device and a VR display device, and improve the light transmittance of the liquid crystal display device.

According to a first aspect of the present disclosure, there is provided a polarized light emitting unit, comprising:

The light emitting unit has a light emitting surface;

a quarter-wave plate arranged on one side of the light-emitting surface of the light-emitting unit;

The polarizing reflective layer is arranged on the side of the quarter-wave plate away from the light-emitting surface.

According to an embodiment of the present disclosure, the polarized reflective layer is a wire grid polarizer.

According to an embodiment of the present disclosure, the transmittance of the wire grid polarizer to linearly polarized light perpendicular to the wire grid direction is not less than 90%.

According to an embodiment of the present disclosure, the reflectivity of the wire grid polarizer to linearly polarized light parallel to the wire grid direction is not less than 80%.

According to an embodiment of the present disclosure, the wire grid height of the wire grid polarizer is between 40 and 220 nm; the wire grid period of the wire grid polarizer is between 30 and 100 nm; The duty cycle of the wire grid is between 10% and 60%.

According to an embodiment of the present disclosure, the quarter-wave plate is disposed on the light-emitting surface of the light-emitting unit, and the polarized reflection layer is disposed on a surface of the quarter-wave plate away from the light-emitting unit.

According to an embodiment of the present disclosure, the quarter-wave plate is connected to the light-emitting surface of the light-emitting unit through optical glue; the polarized reflection layer is away from the quarter-wave plate through optical glue. The surface connection of the light emitting unit.

According to a second aspect of the present disclosure, there is provided a light-emitting substrate, including the above-mentioned polarized light-emitting unit.

According to a third aspect of the present disclosure, there is provided a backlight module, including the above-mentioned light-emitting substrate.

According to an embodiment of the present disclosure, the backlight module further includes a brightness enhancement sheet, and the brightness enhancement sheet is located on the light emitting side of the light emitting substrate.

According to an embodiment of the present disclosure, the distance between the light-emitting substrate and the brightness-enhancing sheet is 2-8 millimeters; the space between the light-emitting substrate and the brightness-enhancing sheet is a medium without birefringence properties.

According to an embodiment of the present disclosure, at least one of a diffusion sheet, a color conversion sheet, and a filter is not provided between the light-emitting substrate and the brightness enhancement sheet.

According to a fourth aspect of the present disclosure, there is provided a backlight module, including:

A light-emitting substrate having a plurality of light-emitting units;

a quarter-wave plate arranged on the light-emitting side of the light-emitting substrate and covering each of the light-emitting units;

The polarizing reflective layer is arranged on the side of the quarter-wave plate away from the light-emitting substrate.

According to an embodiment of the present disclosure, the backlight module further includes a brightness enhancement sheet, and the brightness enhancement sheet is located on a side of the polarized reflection layer away from the light-emitting substrate.

According to a fifth aspect of the present disclosure, there is provided a liquid crystal display device, including the above-mentioned backlight module, and a liquid crystal display module cooperating with the backlight module.

According to a sixth aspect of the present disclosure, a VR display device is provided, including the above-mentioned liquid crystal display device.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description serve to explain the principles of the disclosure. Apparently, the drawings in the following description are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a liquid crystal display device in the related art.

FIG. 2 is a schematic diagram of the principle of a liquid crystal display device in an embodiment of the present disclosure.

FIG. 3 is a schematic diagram of a backlight module in an embodiment of the present disclosure.

Fig. 4 is a schematic structural diagram of a polarized light-emitting unit in an embodiment of the present disclosure.

Fig. 5 is a schematic structural diagram of a polarized light-emitting unit in an embodiment of the present disclosure.

Fig. 6 is a schematic diagram of the principle of a polarized light-emitting unit in an embodiment of the present disclosure.

Fig. 7 is a schematic structural diagram of a polarized light-emitting unit in an embodiment of the present disclosure.

FIG. 8 is a schematic structural diagram of a backlight module in an embodiment of the present disclosure.

FIG. 9 is a schematic structural diagram of a backlight module in an embodiment of the present disclosure.

FIG. 10 is a schematic diagram of a backlight module in an embodiment of the present disclosure.

FIG. 11 is a schematic structural diagram of a backlight module in an embodiment of the present disclosure.

FIG. 12 is a schematic structural diagram of a backlight module in an embodiment of the present disclosure.

FIG. 13 is a schematic structural diagram of a backlight module in an embodiment of the present disclosure.

FIG. 14 is a schematic structural diagram of a backlight module in an embodiment of the present disclosure.

FIG. 15 is a schematic structural diagram of a VR display device in an implementation manner of the present disclosure.

Figure 16-1 is a graph showing the relationship between the wire grid height of the wire grid polarizer and the absorption rate of natural light.

Figure 16-2 is a graph showing the relationship between the wire grid height of the wire grid polarizer and the transmittance to natural light.

Fig. 16-3 is a graph showing the relationship between the height of the wire grid of the wire grid polarizer and the degree of polarization of the transmitted light.

Detailed ways

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed descriptions will be omitted. Furthermore, the drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale.

Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another component, these terms are used in this specification only for convenience, for example, according to the description in the accompanying drawings directions for the example described above. It will be appreciated that if the illustrated device is turned over so that it is upside down, then elements described as being "upper" will become elements that are "lower". When a structure is "on" another structure, it may mean that a structure is integrally formed on another structure, or that a structure is "directly" placed on another structure, or that a structure is "indirectly" placed on another structure through another structure. other structures.

The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements/components/etc; the terms "comprising" and "have" are used to indicate an open and means that there may be additional elements/components/etc. in addition to the listed elements/components/etc.; the terms "first", "second" and "third" etc. only Used as a marker, not a limit on the number of its objects.

In the related art, due to the light absorption of each optical film material of the backlight module BLU, the light output rate of the backlight module BLU is generally only about 65%. The liquid crystal display module LCM needs to convert the non-polarized backlight into linearly polarized light through the first polarizer POLA and provide it to the liquid crystal display panel PNL, which causes at least 50% of the backlight to be lost. In order to further improve the light efficiency of the liquid crystal display device, a multi-layer reflective polarizer may be used to replace the first polarizer POLA, for example, an APF polarizer (Advanced Polarizer Film) may be used to replace the first polarizer POLA. In this way, the light incident on the liquid crystal display panel PNL reaches 52% of the light emitted by the backlight module BLU. Even so, from the light-emitting substrate LBP to the liquid crystal display panel PNL, the light efficiency can only reach 65%*52%=34%, and there is room for further improvement.

In the embodiments of the present disclosure, a liquid crystal display device, and a backlight module BLU and a light-emitting substrate LBP used in the liquid crystal display device are provided, which can further improve the light efficiency from the light-emitting substrate LBP to the liquid crystal display panel PNL.

Referring to FIG. 2 , the liquid crystal display device includes a backlight module BLU and a liquid crystal display module LCM that are stacked together. Wherein, the backlight emitted by the backlight module BLU is linear polarized light instead of non-polarized light. The polarization direction (vibration transmission direction) of the first polarizer POLA of the liquid crystal display module LCM is parallel to the polarization direction of the light emitted by the backlight module BLU. In this way, the linearly polarized backlight emitted by the backlight module BLU can pass through the first polarizer POLA almost without loss. In this implementation manner, it is not necessary to use a multi-layer reflective polarizer instead of the first polarizer POLA, thereby reducing the cost of the liquid crystal display device. Furthermore, by optimizing the BLU of the backlight module, the light efficiency of the linearly polarized light emitted by the BLU of the backlight module can be further improved, thereby directly improving the light efficiency of the liquid crystal display device.

FIG. 3 is a schematic diagram of an optimized structure of a backlight module BLU in some embodiments of the present disclosure. Referring to Fig. 3, the backlight module BLU includes a light-emitting substrate LBP, and the light-emitting substrate LBP includes a driving backplane DBP and an array-distributed polarized light emitting unit PLD located on one side of the driving backplane DBP; The backplane DBP is driven to emit light, and the light emitted by each polarized light emitting unit PLD is linearly polarized light.

In one embodiment of the present disclosure, referring to FIG. 4 , each polarized light-emitting unit PLD includes a light-emitting unit LD, and includes a quarter-wave plate QWP and a polarizing reflective layer sequentially stacked on one side of the light-emitting surface of the light-emitting unit LD. Fa. Wherein, the polarized reflective layer FA is capable of transmitting polarized light, and reflects the light that cannot be transmitted rather than completely absorbing it. Wherein, the transmitted light is linearly polarized light, and the reflected light is also linearly polarized light, and the polarization direction of the transmitted light is opposite to that of the reflected light. In this way, after the non-polarized light (natural light) emitted by the light-emitting unit LD irradiates the polarized reflective layer FA, the light or the polarized component of the light parallel to the vibration transmission direction of the polarized reflective layer FA will be transmitted, and the polarized light with the polarized reflective layer FA will be transmitted. Rays or polarized components of rays that are oriented perpendicularly will be reflected. The reflected linearly polarized light is transformed into circularly polarized light (or elliptically polarized light) after passing through the quarter-wave plate QWP, and then passes through the quarter-wave plate QWP again after being reflected by the light-emitting unit LD, and then transformed into The linearly polarized light parallel to the vibration transmission direction of the reflective layer FA can exit from the polarized reflective layer FA. Therefore, in the polarized light-emitting unit PLD in this embodiment, except for the absorbed light, other light rays can basically emerge from the polarized reflective layer FA and be linearly polarized, which makes the linearly polarized light that the polarized light-emitting unit PLD can provide The efficiency exceeds 50%, for example, it can reach more than 80%. In other words, far more than 50% of the light emitted by the light emitting unit LD can be emitted in a linearly polarized state, for example, more than 80% of the light can be emitted and the emitted light is in a linearly polarized state. This enables the backlight module BLU of the embodiment of the present disclosure to provide linearly polarized light as a backlight with high light efficiency, thereby improving the utilization efficiency of the light emitted by the light emitting unit LD by the liquid crystal display panel PNL.

表示与线栅方向平行的线偏振光。发光单元LD发出的非偏振光经过四分之一波片QWP后照射至线栅偏光片WGP。这些自然光中，与线栅偏光片WGP的线栅方向垂直的光线或者光线的偏振分量，可以从线栅偏光片WGP透射；与线栅偏光片WGP的线栅方向平行的光线或者光线的偏振分量，可以被线栅偏光片WGP反射。线栅偏光片WGP反射的线偏振光经过四分之一波片QWP后转变为圆偏振光(或者椭圆偏振光)，该圆偏振光(或者椭圆偏振光)经过发光单元LD的反射(例如经过发光单元LD内部或者外部的金属结构的反射)后再次穿过四分之一波片QWP，转变为与线栅方向垂直的线偏振光，该线偏振光可以透过线栅偏光片WGP而出射。在图6的示例中，被线栅偏光片WGP反射的线偏振光第一次透过四分之一波片QWP后转变为左旋圆偏振光，该左旋圆偏振光经过发光单元LD的反射后转变为右旋线偏振光。可以理解的是，图6中对圆偏振光的旋转方向仅仅为示例性说明，在本公开的其他实施方式中，该旋转方向可以相反。As an example, referring to FIG. 5 , the polarized reflective layer FA may be a wire grid polarizer WGP. The wire grid polarizer WGP has periodically arranged wire grids GR. The wire grid polarizer WGP can transmit linearly polarized light perpendicular to the wire grid direction (the length direction of the wire grid GR), and reflect linearly polarized light parallel to the wire grid direction. Referring to Figure 6, the left and right arrows represent linearly polarized light perpendicular to the wire grid direction,

Indicates linearly polarized light parallel to the direction of the wire grid. The unpolarized light emitted by the light emitting unit LD passes through the quarter wave plate QWP and then irradiates to the wire grid polarizer WGP. In these natural lights, the light or the polarization component of the light perpendicular to the wire grid direction of the wire grid polarizer WGP can be transmitted from the wire grid polarizer WGP; the light or the polarization component of the light parallel to the wire grid direction of the wire grid polarizer WGP , can be reflected by the wire grid polarizer WGP. The linearly polarized light reflected by the wire grid polarizer WGP is converted into circularly polarized light (or elliptically polarized light) after passing through the quarter-wave plate QWP, and the circularly polarized light (or elliptically polarized light) is reflected by the light-emitting unit LD (for example, through The reflection of the metal structure inside or outside the light emitting unit LD) passes through the quarter-wave plate QWP again, and transforms into linearly polarized light perpendicular to the direction of the wire grid, and the linearly polarized light can be emitted through the wire grid polarizer WGP . In the example shown in Figure 6, the linearly polarized light reflected by the wire grid polarizer WGP passes through the quarter-wave plate QWP for the first time and then turns into left-handed circularly polarized light, and the left-handed circularly polarized light is reflected by the light-emitting unit LD into right-handed linearly polarized light. It can be understood that the rotation direction of the circularly polarized light in FIG. 6 is only for illustration, and in other embodiments of the present disclosure, the rotation direction may be opposite.

In this example, by adjusting the structural parameters of the wire grid polarizer WGP, such as the height H of the wire grid, the pitch of the wire grid (Pitch) P and the duty cycle of the wire grid (the ratio of the width of the wire grid GR to the period of the wire grid) etc. to adjust the transmittance of the wire grid polarizer WGP to linearly polarized light (the polarization direction is perpendicular to the direction of the wire grid), the reflectivity to the linearly polarized light (the polarization direction is parallel to the direction of the wire grid), and the absorptivity of the light, etc., Further, the light effect of the outgoing linearly polarized light is adjusted. Generally, the smaller the wire grid height H of the wire grid polarizer WGP and the smaller the duty cycle, the smaller the absorption rate of the wire grid polarizer WGP to light, the higher the light utilization rate, and the final emitted linearly polarized light The higher the efficiency.

In one embodiment of the present disclosure, the wire grid period of the wire grid polarizer WGP is between 30-100 nm, and the wire grid height of the wire grid polarizer WGP is between 40-220 nm.

In one embodiment of the present disclosure, the duty ratio of the wire grid of the wire grid polarizer WGP is between 10% and 60%.

In one embodiment of the present disclosure, the structural parameters of the wire grid polarizer WGP can be adjusted so that the transmittance of the wire grid polarizer WGP to linearly polarized light perpendicular to the wire grid direction is not less than 90%.

In one embodiment of the present disclosure, the structural parameters of the wire grid polarizer WGP can be adjusted so that the reflectivity of the wire grid polarizer WGP for linearly polarized light parallel to the wire grid direction is not less than 80%.

Figure 16-1 illustrates the relationship curve between the absorptivity of a wire grid polarizer WGP for light (natural light) and the height H of the wire grid, wherein the wire grid period of the wire grid polarizer WGP is 60nm, and the wire grid occupies The empty ratio is 40%. According to Figure 16-1, within the test range, the larger the wire grid height of the wire grid polarizer WGP, the higher the light absorption rate of the wire grid polarizer WGP, the greater the light loss, and the lower the light output efficiency.

Figure 16-2 illustrates the relationship curve between the transmittance of a wire grid polarizer WGP to light (natural light) and the height H of the wire grid, wherein the wire grid period of the wire grid polarizer WGP is 60nm, and the wire grid The duty cycle is 40%. According to Figure 16-2, within the test range, the larger the wire grid height of the wire grid polarizer WGP, the smaller the light transmittance of the wire grid polarizer WGP, the greater the light loss, and the lower the light output efficiency.

Figure 16-3 illustrates the relationship curve between the degree of polarization of the transmitted light and the height H of the wire grid polarizer WGP, where the wire grid period of the wire grid polarizer WGP is 60nm, and the duty cycle of the wire grid is 60nm. 40%. According to Figure 16-3, within the test range, the outgoing light of the wire grid polarizer WGP has a high degree of polarization. For example, when the height H of the wire grid is 80nm, the degree of polarization reaches 99.7%, The degree of polarization basically reaches 100%.

According to the relationship curves between the absorptivity, transmittance and degree of polarization and the height of the wire grid shown in Figure 16-1, Figure 16-2, and Figure 16-3, it can be known that when the wire grid height H of the wire grid polarizer WGP is 80nm, the wire grid period P of the wire grid polarizer WGP is 60nm, and the wire grid duty cycle is 40%, the wire grid polarizer WGP can fully meet the performance requirements of the disclosed embodiment for the wire grid polarizer WGP. At this time, the transmittance of the wire grid polarizer WGP to the polarized light perpendicular to the wire grid direction is about 94%, and the reflectance to the polarized light parallel to the wire grid direction is about 84%. The degree is 99.7%.

It can be understood that the structural parameters of the above-mentioned wire grid polarizer WGP (the wire grid height H is 80nm, the wire grid period P is 60nm, and the wire grid duty ratio is 40%) are only one example of the wire grid polarizer WGP in the present disclosure. structure parameters. According to the needs and process, the wire grid polarizer WGP can adopt other structural parameters.

In the above examples, the structure, principle and effect of the polarized light-emitting unit PLD provided by the embodiments of the present disclosure are exemplarily described by taking the polarized reflection layer FA as a wire grid polarizer WGP as an example. It can be understood that in other embodiments of the present disclosure, other types of polarizing reflection layers can also be used.

In the embodiments of the present disclosure, the quarter-wave plate QWP may adopt a metasurface structure, and may also be prepared by using cyclo olefin polymer (Cyclo Olefin Polymer, COP) or polycarbonate (PC). Of course, the quarter wave plate QWP can also be made of other materials.

In an embodiment of the present disclosure, referring to FIG. 4 , the quarter wave plate QWP may be directly formed on the light emitting surface of the light emitting unit LD. In another implementation manner, referring to FIG. 7 , the quarter-wave plate QWP may be connected to the light-emitting surface of the light-emitting unit LD through the first optical adhesive layer OCA. Of course, the quarter-wave plate QWP can also be stacked and fixed with the light-emitting unit LD in other ways, for example, by sealing glue, frame, bonding or other ways to achieve stacking.

In an embodiment of the present disclosure, referring to FIG. 4 , the polarized reflection layer FA may be directly formed on the surface of the quarter wave plate QWP away from the light emitting unit LD. In another implementation manner, referring to FIG. 7 , the polarized reflective layer FA may be connected to the surface of the quarter wave plate QWP away from the light emitting unit LD through the second optical adhesive layer OCB. Of course, the polarized reflective layer FA can also be laminated and fixed with the quarter-wave plate QWP in other ways, for example, by using sealant, frame, bonding or other ways to achieve lamination.

In one example, referring to FIG. 7 , the quarter wave plate QWP is connected to the light emitting surface of the light emitting unit LD through optical glue OC; the polarized reflection layer FA is connected to the quarter wave plate through optical glue OC A wave plate QWP is connected away from the surface of the light emitting unit LD.

In another example, referring to FIG. 4 , the quarter-wave plate QWP is disposed on the light-emitting surface of the light emitting unit LD, and the polarized reflection layer FA is disposed on the quarter-wave plate QWP away from all The surface of the light emitting unit LD.

In one example, the polarized light-emitting units PLD on the light-emitting substrate LBP may include a plurality of different colors of polarized light-emitting units PLD, so that the polarized light-emitting units PLD of different colors emit different lights for color mixing, so that the backlight module BLU can provide White linear polarized backlight.

Of course, in other examples of the present disclosure, the colors of the polarized light emitting units PLD on the light emitting substrate LBP may also be the same. For example, each polarized light-emitting unit PLD can emit a plurality of different colors of light (such as red light, green light and blue light) for light mixing (for example, each light-emitting unit LD is integrated with a plurality of light-emitting structures of different colors), so as to The color of the light emitted by each polarized light emitting unit PLD meets the requirements of the backlight module BLU on the light color (for example, white). For another example, each polarized light-emitting unit PLD all emits light of the same color (such as blue light); a pixelated color conversion film (such as quantum dots) is set on the side of the second polarizer POLB of the liquid crystal display module LCM away from the liquid crystal display panel PNL. film), and then achieve color conversion on the color conversion film to achieve color display.

Optionally, the light emitting unit LD may be a micro light emitting diode, such as a submillimeter light emitting diode (MiniLight Emitting Diode, Mini LED) or a micro light emitting diode (Micro Light Emitting Diode, Micro LED). Further, the size of the submillimeter light emitting diode is in the range of 100-400 μm; the size of the micro light emitting diode is below 100 μm. Certainly, the light emitting unit LD of the present disclosure may also be other light emitting elements as required.

Optionally, the driving backplane DBP may include a stacked base substrate and a driving layer, and the driving layer is provided with a driving circuit for driving the polarized light-emitting unit PLD. The driving circuit may be an active driving circuit or a passive driving circuit. Drive circuit. In an example, a bonding pad for bonding the light emitting unit LD is disposed on the driving layer, and the light emitting unit LD can be bonded and connected to the bonding pad.

In one embodiment of the present disclosure, the type and quantity of optical film materials on the side of the polarized light-emitting unit PLD away from the driving backplane DBP of the backlight module BLU may be less than that of the prior art, such as the backlight module The BLU may not be provided with at least one of a diffusion sheet, a color conversion sheet (such as a fluorescent sheet or a quantum dot sheet) and an optical filter, especially without a color conversion sheet. In this way, by reducing the number and types of optical films on the light output path of the polarized light-emitting unit PLD, the depolarization of linearly polarized light by these optical films can be reduced, so that the backlight module BLU can provide a high degree of polarization to the liquid crystal display module LCM linearly polarized light, for example, so that the polarization degree of the provided backlight is not lower than 70%. In one example, by adjusting the quantity and type of the optical film material on the side away from the driving backplane DBP of the polarized light-emitting unit PLD, the polarization degree of the light emitted by the backlight module BLU is between 75% and 85%, and then Reduce the light loss of linearly polarized backlight when passing through the first polarizer POLA.

In one example, the backlight module BLU may not be provided with a diffusion sheet, a color conversion sheet (such as a fluorescent sheet or a quantum dot sheet) and a filter.

In one example, the backlight module BLU may be provided with a brightness enhancing sheet on a side of the polarized light emitting unit PLD away from the driving backplane DBP, so as to focus and enhance the backlight to increase the brightness of the backlight. According to needs, the number of layers of the brightening sheet can be one layer or multiple layers. For example, in the example shown in FIG. 3 , the backlight module BLU is provided with two layers of brightness enhancement sheets on the side of the polarized light emitting unit PLD away from the drive backplane DBP, that is, a first brightness enhancement sheet BEF1 and a second brightness enhancement sheet are provided. BEF2. In this way, by arranging two layers of brightness-enhancing sheets, it is possible to sufficiently gather light to enhance brightness, and avoid excessive depolarization of linearly polarized light due to too many optical film materials or too thick thickness, and avoid optical The light transmittance is reduced due to too many film materials or too large thickness; on the whole, the backlight module BLU is equipped with two layers of brightening sheets, which can reduce light loss and low depolarization in terms of concentrated light and brightening, high light transmittance A balance is achieved in terms of reducing light loss, etc., to finally ensure that the liquid crystal display device has high light efficiency.

In one example, the total transmittance of the two layers of brightness enhancing sheets is about 84%, and the total deflection of the two layers of brightness enhancing sheets is about 20%. Taking the transmittance of the first polarizer POLA to natural light as 43% as an example, the transmittance of the first polarizer POLA to linearly polarized light parallel to its polarization direction (also known as the transmission axis direction or the vibration transmission direction) The rate is 86%.

Then, the formula for calculating the ratio of the light emitted by the light-emitting unit LD to the liquid crystal display panel PNL is: (X ₁ *50%+50%*X ₂ *X ₁ )*X ₃ *(1-X ₄ )*X ₅ . In this formula, X ₁ represents the transmittance of the polarized reflective layer FA to linearly polarized light parallel to its transmission direction; X ₂ represents the reflectance of the polarized reflective layer FA to linearly polarized light perpendicular to its transmittance direction; X ₃ Indicates the total transmittance of the two-layer brightness enhancement sheet; X ₄ indicates the total depolarization degree of the two-layer brightness enhancement sheet; X ₅ indicates the transmittance of the first polarizer POLA to linearly polarized light parallel to its transmission direction.

According to the above formula, the natural light emitted by the light-emitting unit LD can be calculated, and the light effect that finally reaches the liquid crystal display panel PNL in the form of linearly polarized light is (94%*50%+50%*84%*94%)*84%* (1-20%)*86%=50%. Compared with the improved solution using APF polarizers in the related art (the light efficiency is 34%), the light efficiency of this example is improved by at least 47%.

In an embodiment of the present disclosure, referring to FIG. 8 , there may be a certain distance between the brightness enhancement sheet and the light-emitting substrate LBP to facilitate light mixing of the polarized light-emitting unit PLD and improve the brightness uniformity of the light emitted by the backlight module BLU. Exemplarily, the distance between the brightness enhancement sheet and the light-emitting substrate LBP can be between 2 mm and 8 mm, so that the brightness uniformity of the backlight module BLU is not less than 80%, especially to make the brightness uniformity of the backlight module BLU Sex is not less than 90%. In one example, the distance between the brightness enhancement sheet and the light-emitting substrate LBP may be between 4 mm and 6 mm, so that the brightness uniformity of the backlight module BLU is about 90%. For example, in one example, the distance between the brightness enhancement sheet and the light-emitting substrate LBP is 5mm, and the brightness uniformity of the backlight module BLU is 90%.

It can be understood that the distance between the brightness enhancement sheet and the light-emitting substrate LBP is related to various factors. In order to achieve the expected brightness uniformity, in addition to adjusting the distance between the brightness enhancement sheet and the light-emitting substrate LBP, you can also adjust the polarized light-emitting unit The spacing between the PLDs can be achieved by adding diffusion sheets when necessary. In a large-size display device such as a TV, since it is not sensitive to the thickness of the backlight module BLU, higher brightness uniformity can be achieved mainly by increasing the distance between the brightness enhancement sheet and the light-emitting substrate LBP.

In one example, referring to FIG. 8 , the distance between the brightness enhancement sheet and the light-emitting substrate LBP may be maintained by a mechanical frame FRM, for example, the mechanical frame FRM is used to support and fix the brightness enhancement sheet. In this way, an air cavity may be formed between the brightness enhancement sheet and the light-emitting substrate LBP for light mixing. Of course, when necessary, the air cavity can also be filled with a material with high light transmission and no birefringence characteristics, or a support structure using such material can be set to support the brightness enhancement sheet, thereby improving the collimation of the outgoing backlight.

In another example, referring to FIG. 9 , an optical distance adjustment sheet ODM can be arranged between the brightness enhancement sheet and the light-emitting substrate LBP, and the distance between the brightness enhancement sheet and the light-emitting substrate LBP is maintained by the optical distance adjustment sheet ODM. The optical path adjustment plate ODM cannot use materials with birefringence characteristics, and try to have high light transmittance. The optical distance adjusting sheet ODM may be one layer of material, or may include multiple layers of material stacked together, or may be a multi-layered optical film material.

FIG. 8 and FIG. 9 illustrate two implementations for maintaining a distance between the light-emitting substrate LBP and the brightness enhancement sheet. It can be understood that, in the backlight module BLU of the embodiment of the present disclosure, other ways can also be used to maintain the distance between the light-emitting substrate LBP and the brightness enhancement sheet, for example, a support structure is provided between the two, so that the In the case of light transmittance and no large depolarization, there is a gap between the light-emitting substrate LBP and the brightness enhancement sheet.

FIG. 10 shows a schematic diagram of the principle of a backlight module BLU in some other embodiments of the present disclosure. Referring to FIG. 10, the backlight module BLU includes a stacked light-emitting substrate LBP, a quarter-wave plate QWP, and a polarized reflection layer FA. The light-emitting substrate LBP includes a driving backplane DBP and a plurality of Light-emitting units LD (such as light-emitting units LD arranged in an array); the light-emitting units LD emit light under the driving of the driving backplane DBP, and the light emitted by each light-emitting unit LD may be non-polarized light (natural light). The quarter wave plate QWP can be arranged on the light emitting side of the light emitting unit LD, and cover each light emitting unit LD. The polarization reflective layer FA may cover each light emitting unit LD. In this way, the natural light emitted by the light-emitting substrate LBP can be emitted efficiently after passing through the quarter-wave plate QWP and the polarized reflection layer FA, and the emitted light is linearly polarized light. Wherein, the material and characteristics of the quarter-wave plate QWP covering each light-emitting unit LD may be the same as that of the quarter-wave plate QWP on the polarized light-emitting unit PLD, of course, may also be different. The material and properties of the polarized reflective layer FA covering each light emitting unit LD may be the same as those of the polarized reflective layer FA on the polarized light emitting unit PLD, of course, may also be different.

In one embodiment of the present disclosure, referring to FIG. 11 , the quarter-wave plate QWP can be arranged close to the light-emitting substrate LBP, and the polarizing reflection layer FA can be arranged close to the quarter-wave plate QWP, so as to facilitate the backlight module BLU. assembly. Of course, in other embodiments of the present disclosure, there may be a certain distance between the polarized reflective layer FA and the light-emitting substrate LBP to facilitate light mixing; the polarized reflective layer FA reflects the polarized light perpendicular to the vibration transmission direction, It is equivalent to increasing the optical path of part of the emitted light in the BLU of the backlight module, thereby improving the light mixing effect and uniformity of light emitted by the BLU of the backlight module. Exemplarily, there is a gap between the quarter-wave plate QWP and the light-emitting substrate LBP, so that there is a pre-designed distance between the polarizing reflective layer FA and the light-emitting substrate LBP.

In one embodiment of the present disclosure, referring to FIG. 11 , the quarter-wave plate QWP and the polarizing reflection layer FA can be directly laminated without setting other film layers or materials, for example, the polarizing reflection layer FA is directly formed on the quarter-wave plate QWP. One wave plate QWP surface. In another embodiment, referring to FIG. 12 , the quarter-wave plate QWP is connected to the polarizing reflection layer FA through optical glue OC. In this way, the assembly of the backlight module BLU is facilitated.

In one embodiment of the present disclosure, the type and quantity of the optical film material on the side of the polarizing reflection layer FA away from the driving backplane DBP of the backlight module BLU may be less than that of the prior art, such as the backlight module The BLU may not be provided with at least one of a diffusion sheet, a color conversion sheet (such as a fluorescent sheet or a quantum dot sheet) and an optical filter, especially without a color conversion sheet. In this way, by reducing the number and types of optical films on the optical path of the linearly polarized backlight, the depolarization of linearly polarized light by these optical films can be reduced, so that the backlight module BLU can provide the liquid crystal display module LCM with high polarization linear Polarized light, for example such that the degree of polarization of the provided backlight is not lower than 70%. In one example, by adjusting the quantity and type of the optical film material on the side of the polarized reflection layer FA away from the driving backplane DBP, the polarization degree of the light emitted by the backlight module BLU is between 75% and 85%, and then Avoid the light loss of the linearly polarized backlight when passing through the first polarizer POLA.

In one example, the backlight module BLU may be provided with a brightness enhancement sheet on a side of the polarizing reflection layer FA away from the driving backplane DBP, so as to focus and enhance the backlight to increase the brightness of the backlight. According to needs, the number of layers of the brightening sheet can be one layer or multiple layers. For example, in the example shown in FIG. 11 , the backlight module BLU is provided with two layers of brightness enhancement sheets on the side of the polarization reflection layer FA away from the drive backplane DBP, that is, the first brightness enhancement sheet BEF1 and the second brightness enhancement sheet are provided. BEF2. In this way, by arranging two layers of brightness-enhancing sheets, it is possible to sufficiently gather light to enhance brightness, and avoid excessive depolarization of linearly polarized light due to too many optical film materials or too thick thickness, and avoid optical The light transmittance is reduced due to too many film materials or too large thickness; on the whole, the backlight module BLU is equipped with two layers of brightening sheets, which can reduce light loss and low depolarization in terms of concentrated light and brightening, high light transmittance A balance is achieved in terms of reducing light loss, ensuring that the intensity of linearly polarized light in the final linearly polarized backlight is maintained at a higher level than the light intensity of the light emitting unit LD, and finally ensuring the utilization of the backlight by the liquid crystal display panel PNL.

In an embodiment of the present disclosure, referring to FIG. 12 , there may be a certain distance between the brightness enhancement sheet and the light-emitting substrate LBP to facilitate light mixing of the light-emitting unit LD and improve the brightness uniformity of the light emitted by the backlight module BLU. Exemplarily, the distance between the brightness enhancement sheet and the light-emitting substrate LBP can be between 2 mm and 8 mm, so that the brightness uniformity of the backlight module BLU is not less than 80%, especially to make the brightness uniformity of the backlight module BLU Sex is not less than 90%.

In one embodiment of the present disclosure, the polarized reflective layer FA may be disposed close to the brightness enhancement sheet, for example, the polarized reflective layer FA is attached to a side of the brightness enhancement sheet close to the light-emitting substrate LBP. In this way, the polarized reflective layer FA can increase the optical path of this part of the light in the backlight module BLU by using its reflection effect on the linearly polarized light perpendicular to the vibration transmission direction, thereby improving the light mixing effect of the backlight module BLU. It is beneficial to reduce the distance between the brightness enhancement sheet and the light-emitting substrate LBP, and is beneficial to the thinning of the backlight module BLU.

In one example, referring to FIG. 13 , the distance between the brightness enhancement sheet and the light-emitting substrate LBP can be maintained by a mechanical frame FRM, for example, the mechanical frame is used to support and fix the brightness enhancement sheet. In this way, an air cavity may be formed between the brightness enhancement sheet and the light-emitting substrate LBP for light mixing. Of course, when necessary, the air cavity can also be filled with a material with high light transmission and no birefringence characteristics, or a support structure using such material can be set to support the brightness enhancement sheet, thereby improving the collimation of the outgoing backlight.

In another example, referring to FIG. 14 , an optical distance adjustment sheet ODM can be arranged between the brightness enhancement sheet and the light-emitting substrate LBP, and the distance between the brightness enhancement sheet and the light-emitting substrate LBP can be maintained by the optical distance adjustment sheet ODM. The optical path adjustment plate ODM cannot use materials with birefringence characteristics, and try to have high light transmittance. The optical distance adjusting sheet ODM may be one layer of material, or may include multiple layers of material stacked together, or may be a multi-layered optical film material.

FIG. 13 and FIG. 14 illustrate two implementations for maintaining a distance between the light-emitting substrate LBP and the brightness enhancement sheet. It can be understood that, in the backlight module BLU of the embodiment of the present disclosure, other ways can also be used to maintain the distance between the light-emitting substrate LBP and the brightness enhancement sheet, for example, a support structure is provided between the two, so that the In the case of light transmittance and no large depolarization, there is a gap between the light-emitting substrate LBP and the brightness enhancement sheet.

In the examples shown in FIG. 13 and FIG. 14 , the polarized reflective layer FA is disposed close to the light-emitting substrate LBP and has a certain distance from the brightness enhancement sheet. It can be understood that, in some other embodiments of the present disclosure, the polarized reflection layer FA may also be directly stacked with the brightness enhancement sheet or bonded by optical glue, so that the polarization reflection layer FA supports the brightness enhancement sheet. For example, the mechanical frame FRM can support the polarized reflective layer FA, so that there is a certain gap between the polarized reflective layer FA and the light-emitting substrate LBP; the brightness enhancement sheet can be directly stacked on the side of the polarized reflective layer FA away from the light-emitting substrate LBP. For another example, the polarized reflective layer FA is disposed on the side of the optical path adjustment sheet ODM away from the light-emitting substrate LBP, and the brightness enhancement sheet is stacked on the side of the polarized reflective layer FA away from the light-emitting substrate LBP.

In one example, the light-emitting units LD on the light-emitting substrate LBP may include multiple light-emitting units LD of different colors, so that the light-emitting units LD of different colors emit different lights for color mixing, so that the backlight module BLU can provide white linear polarization backlight.

Of course, in other examples of the present disclosure, the colors of the light emitting units LD on the light emitting substrate LBP may also be the same. For example, each light emitting unit LD can emit a plurality of different colors of light (such as red light, green light and blue light) for light mixing (for example, each light emitting unit LD is integrated with a plurality of light emitting structures of different colors), so that The color of the light emitted by each light emitting unit LD meets the requirements of the backlight module BLU on the light color (eg, white). For another example, each light-emitting unit LD emits light of the same color (such as blue light); a pixelated color conversion film (such as a quantum dot film) is set on the side of the second polarizer POLB of the liquid crystal display module LCM away from the liquid crystal display panel PNL ), and then achieve color conversion on the color conversion film to achieve color display.

Embodiments of the present disclosure further provide a VR (Virtual Reality) display device, which includes any liquid crystal display device described in the above embodiments of the liquid crystal display device. Fig. 15 illustrates a schematic structural diagram of a VR display device. Referring to FIG. 15 , the VR display device includes a stacked liquid crystal display device and a folded optical path system. The folded optical path system is arranged on the display side of the liquid crystal display device to converge light to the user's eyes. The folded optical path system can reduce the thickness of the folded optical path system by folding the optical path, which is beneficial to thinning and thinning the VR display device. At the same time, the liquid crystal display device has higher brightness by improving the light utilization rate, thereby meeting the high brightness requirement of the VR display device for the liquid crystal display device.

Exemplarily, referring to FIG. 15 , the folded optical path system includes a first quarter wave plate (1/4 wave plate 1 ), a semi-transparent Reflective film, first lens (LENS1), second quarter wave plate (1/4 wave plate 2), polarizing reflective film and second lens (LENS2). The light of the liquid crystal display device is linearly polarized light, which is converted into circularly polarized light (or elliptically polarized light) through the first quarter-wave plate; The first lens and the second quarter-wave plate then become linearly polarized light, and the polarization direction of the linearly polarized light is deflected by 90° compared to when it exits from the liquid crystal display module LCM. After the linearly polarized light is reflected by the polarized reflective film (the optical path is folded for the first time), it is transformed into circularly polarized light (or elliptically polarized light) after passing through the second quarter-wave plate, and continues to pass through the first lens LENS1 for irradiation To the transflective film; the circularly polarized light (or elliptically polarized light) is reflected by the semi-transparent film (due to the loss of half of the transmission) and then folds the optical path for the second time, and the reflected light passes through the first lens LENS1 and then passes through The second quarter-wave plate converts circularly polarized light (or elliptically polarized light) to linearly polarized light. At this time, the polarization direction of the linearly polarized light is deflected by 90° compared with the linearly polarized light when the optical path is folded for the first time, and the linearly polarized light can be transmitted through the polarizing reflection film. The light transmitted from the polarizing reflective film is converged to human eyes through the second lens to realize imaging.

In this example, since light is transmitted and reflected once by using a transflective film in the folded optical path system, the light efficiency is reduced to 1/4, which makes the VR display device particularly require a high-brightness liquid crystal display device. However, the liquid crystal display device provided by the embodiments of the present disclosure can achieve high brightness by improving the light efficiency, and is especially suitable for meeting the requirements of the VR display device.

It can be understood that FIG. 15 is only an example of a VR display device provided in an embodiment of the present disclosure. The liquid crystal display device provided by the embodiments of the present disclosure can achieve high brightness and low power consumption, and thus is also applicable to other types of VR display devices.

The embodiments of the present disclosure merely exemplify the application of the liquid crystal display device in the VR display device. It can be understood that the liquid crystal display device of the present disclosure can not only be applied in the field of VR, but also in televisions, billboards, displays, vehicle panels, mobile terminals, AR (augmented reality) display devices or other fields that require display devices. The liquid crystal display devices of the disclosed embodiments are also applicable.

Other embodiments of the present disclosure will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, and these modifications, uses or adaptations follow the general principles of the present disclosure and include common knowledge or conventional technical means in the technical field not disclosed in the present disclosure . The specification and examples are to be considered exemplary only, with the true scope and spirit of the disclosure indicated by the appended claims.

Claims (17)

1. A polarized light-emitting unit, characterized in that, comprising: The light emitting unit has a light emitting surface; a quarter-wave plate arranged on one side of the light-emitting surface of the light-emitting unit; The polarizing reflective layer is arranged on the side of the quarter-wave plate away from the light-emitting surface. 2 . The polarized light emitting unit according to claim 1 , wherein the polarized reflective layer is a wire grid polarizer. 3 . 3. The polarized light-emitting unit according to claim 2, wherein the transmittance of the wire grid polarizer to linearly polarized light perpendicular to the wire grid direction is not less than 90%. 4 . The polarized light emitting unit according to claim 2 , wherein the reflectance of the wire grid polarizer to linearly polarized light parallel to the wire grid direction is not less than 80%. 5. The polarized light-emitting unit according to claim 2, wherein the wire grid height of the wire grid polarizer is between 40 and 220 nm; the wire grid period of the wire grid polarizer is between 30 and 100 nm ; The duty cycle of the wire grid of the wire grid polarizer is between 10% and 60%. 6. The polarized light-emitting unit according to claim 5, wherein the wire grid height of the wire grid polarizer is 80nm; the wire grid period of the wire grid polarizer is 60nm; The duty cycle of the wire grid is 40%. 7. The polarized light-emitting unit according to any one of claims 1-6, wherein the quarter-wave plate is arranged on the light-emitting surface of the light-emitting unit, and the polarized reflection layer is arranged on the four-wave plate. The one-quarter wave plate is far away from the surface of the light emitting unit. 8. The polarized light-emitting unit according to any one of claims 1-6, wherein the quarter-wave plate is connected to the light-emitting surface of the light-emitting unit through optical glue; The glue is connected to the surface of the quarter-wave plate away from the light-emitting unit. 9. A light-emitting substrate, characterized by comprising a plurality of polarized light-emitting units according to any one of claims 1-8. 10. A backlight module, characterized by comprising the light-emitting substrate according to claim 9. 11. The backlight module according to claim 10, characterized in that the backlight module further comprises a brightness enhancement sheet, and the brightness enhancement sheet is located on the light emitting side of the light emitting substrate. 12. The backlight module according to claim 10, characterized in that, the distance between the light emitting substrate and the brightness enhancing sheet is 2 to 8 millimeters; there is no birefringence between the light emitting substrate and the brightness enhancing sheet characteristic medium. 13. The backlight module according to claim 10, wherein at least one of a diffusion sheet, a color conversion sheet and a filter is not provided between the light-emitting substrate and the brightness enhancement sheet. 14. A backlight module, characterized in that it comprises: A light-emitting substrate having a plurality of light-emitting units; a quarter-wave plate arranged on the light-emitting side of the light-emitting substrate and covering each of the light-emitting units; The polarizing reflective layer is arranged on the side of the quarter-wave plate away from the light-emitting substrate. 15. The backlight module according to claim 14, characterized in that the backlight module further comprises a brightness enhancement sheet, and the brightness enhancement sheet is located on a side of the polarized reflection layer away from the light-emitting substrate. 16. A liquid crystal display device, characterized by comprising the backlight module according to any one of claims 10-15, and a liquid crystal display module cooperating with the backlight module. 17. A VR display device, comprising the liquid crystal display device according to claim 16.

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