CN109814303B - A reflective liquid crystal display panel, its manufacturing method, and display device - Google Patents

Abstract

The invention provides a reflective liquid crystal display panel, a preparation method thereof, and a display device, which belong to the field of display technology and can solve the problem of the yellowish picture in the existing reflective LCD. In the reflective liquid crystal display panel of the present invention, by adjusting the thicknesses of the liquid crystal layers at different positions, the liquid crystal layers corresponding to the sub-pixels have different phase delays, thereby performing predetermined phase compensation for light in different wavelength ranges in the incident light, which is quite It uses liquid crystal layers of different thicknesses to selectively reflect incident light and reflect incident light within a certain wavelength range, so as to achieve the purpose of adjusting the display effect.

Description

A reflective liquid crystal display panel, its manufacturing method, and display device

technical field

The invention belongs to the field of display technology, and in particular relates to a reflective liquid crystal display panel, a preparation method thereof, and a display device.

Background technique

According to the type of light source used and the way the light source is set up, liquid crystal displays can be classified into transmissive liquid crystal displays, semi-transmissive liquid crystal displays, and reflective liquid crystal displays. As far as the reflective liquid crystal display is concerned, it displays images by reflecting ambient light or reflecting light emitted by a light source disposed in front of the display panel. Due to its low power consumption, high aperture ratio, and no need for backlight, reflective liquid crystal displays have great market potential in the fields of e-books and electronic labels.

The inventors have found that there are at least the following problems in the prior art: current reflective LCDs have problems such as yellowing of the picture. For the problem of yellowish screen in reflective liquid crystal display, the commonly used solutions are: 1. Adjust the color filter (CF) color resistance. However, this method is limited by the blue photoresist material and cost, and its manufacturing process is relatively limited, and the adjustment effect is not obvious; 2. Add dye particles that can absorb yellow visible light to the pressure-sensitive adhesive structure of the upper polarizer. This method has a certain effect on white screen vision, but reduces the overall output rate and increases the cost of the polarizer, making it difficult for the product to be competitive in the market.

Contents of the invention

Aiming at the problem of yellowish screen in the existing reflective LCD, the present invention provides a reflective liquid crystal display panel, a preparation method thereof, and a display device.

The technical solution adopted to solve the technical problems of the present invention is:

A reflective liquid crystal display panel, comprising two opposite substrates, and a liquid crystal layer arranged between the first substrate and the second substrate, the second substrate is provided with a reflector, and the first A polarizer and a phase retarder are arranged on a substrate; wherein the side of the first substrate or the second substrate close to the liquid crystal layer is provided with a raised portion, so that the liquid crystal layer is positioned at the position where the raised portion is provided. The thickness of is different from the thickness of the liquid crystal layer at the position where the protrusion is not provided.

Optionally, the substrate close to the light-incident side is the first substrate, and the substrate away from the light-incident side is the second substrate, and the protrusion is provided on the side of the first substrate close to the liquid crystal layer.

Optionally, the raised portion includes a plurality of protrusions protruding toward the liquid crystal layer, and the protrusions are made of a transparent material.

Optionally, one sub-pixel is correspondingly provided with multiple protrusions.

Optionally, a color filter is provided between the first substrate and the protrusion.

Optionally, in a direction perpendicular to the substrate, the dimension between the protrusion corresponding to the sub-pixel and the second substrate is d, and the phase retardation of the liquid crystal layer corresponding to the sub-pixel is Re=Δn *d, wherein, the liquid crystal layer includes liquid crystal molecules, and Δn is the difference in refractive index between the long axis and the short axis of the liquid crystal molecules.

Optionally, the raised portion is disposed on a side of the second substrate close to the liquid crystal layer, and the reflector is disposed between the raised portion and the liquid crystal layer.

Optionally, a polarizer is provided on a side of the first substrate away from the liquid crystal layer.

Optionally, the phase retarder includes a 1/2 wave plate and a 1/4 wave plate.

The present invention also provides a display device, comprising the above-mentioned reflective liquid crystal display panel, and a light source provided on the light-emitting side of the reflective liquid crystal display panel.

Description of drawings

1 is a schematic structural view of a reflective liquid crystal display panel according to Embodiment 1 of the present invention;

2 is a schematic structural view of a reflective liquid crystal display panel according to Embodiment 2 of the present invention;

FIG. 3 is a top view of a protrusion arrangement structure in a sub-pixel according to Embodiment 2 of the present invention;

FIG. 4 is a top view of the arrangement structure of protrusions in another sub-pixel according to Embodiment 2 of the present invention;

5 is a schematic structural view of a reflective liquid crystal display panel according to Embodiment 2 of the present invention;

6 is a schematic structural diagram of another reflective liquid crystal display panel according to Embodiment 2 of the present invention;

7 is a schematic structural diagram of yet another reflective liquid crystal display panel according to Embodiment 2 of the present invention;

8 is a schematic diagram of light propagation in a reflective liquid crystal display panel according to Embodiment 2 of the present invention;

FIG. 9 is a graph showing the relationship between different retardation values produced by the liquid crystal layer of the display panel according to Embodiment 2 of the present invention and the output ratio of high-wavelength light;

FIG. 10 is a graph showing the relationship between the different retardation values produced by the liquid crystal layer of the display panel in Example 2 of the present invention and the low-band light emission rate;

FIG. 11 is a graph showing the relationship between the different retardation values produced by the liquid crystal layer of the display panel in Example 2 of the present invention and the full-band light emission rate;

Wherein, the reference signs are: 1. first substrate; 2. second substrate; 3. liquid crystal layer; 4. reflector; 5. raised portion; 51. protrusion; 6. subpixel; 7. polarizer; 8. Phase retarder; 81. 1/2 wave plate; 82. 1/4 wave plate.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

This embodiment provides a reflective liquid crystal display panel, as shown in FIG. , wherein a reflector 4 is provided on the second substrate 2, a polarizer 7 and a phase retardation film 8 are provided on the first substrate 1; wherein, a side of the first substrate 1 or the second substrate 2 close to the liquid crystal layer is provided with The protruding portion 5 is provided so that the thickness of the liquid crystal layer at the position where the protruding portion 5 is provided is different from the thickness of the liquid crystal layer at the position where the protruding portion is not provided.

In the reflective liquid crystal display panel of the present embodiment, the thickness of the liquid crystal layer 3 at different positions is adjusted by setting the protruding portion 5, so that the incident light is polarized by the polarizer 7 and then converted into circularly polarized light through the phase retarder 8, and then incident on the For the liquid crystal layer, since the thickness of the liquid crystal layer 3 corresponding to the sub-pixels is different, the liquid crystal layer with different thicknesses has different phase retardation for light of different wavelengths, so that the light of different wavelength ranges in the incident light can be selectively pre-determined. Phase compensation, that is, the incident circularly polarized light of a certain wavelength is still emitted in the form of circularly polarized light after being reflected by the liquid crystal layer 3 and the reflector 4, while the incident circularly polarized light of other wavelengths may become elliptically polarized light after passing through the liquid crystal layer, and its outgoing rate is relatively low. It is equivalent to using liquid crystal layers 3 with different thicknesses to selectively reflect incident light of different wavelengths and reflect incident light within a certain range of wavelengths, so as to achieve the purpose of adjusting the display effect.

Example 2:

This embodiment provides a reflective liquid crystal display panel, as shown in Figure 2, comprising a first substrate 1 close to the light-incident side, a second substrate 2 away from the light-incident side, and a liquid crystal layer disposed between the two substrates 3; wherein the second substrate 2 is provided with a reflector 4, and the side of the first substrate 1 away from the liquid crystal layer is provided with a polarizer 7 and a phase retarder 8; wherein, the side of the first substrate 1 close to the other substrate is provided The raised portion 5 is provided so that the thickness of the liquid crystal layer at the position where the raised portion 5 is provided is different from the thickness of the liquid crystal layer at a position where the raised portion is not provided.

The accompanying drawing 2 disclosed in this embodiment shows that the opposite first substrate 1 is provided with a protruding portion 5 on the side close to the second substrate 2, and the liquid crystal layer 3 at different positions is defined by the protruding portion 5 in a direction perpendicular to the substrate. Dimensions in the direction. That is to say, the raised portion 5 is added at the position corresponding to the substrate of the sub-pixel that requires phase retardation. Due to the existence of the raised portion 5, it occupies part of the position of the liquid crystal layer 3, so that the position with the raised portion 5 The liquid crystal layer 3 is relatively thinner. It should be noted that a substrate with an uneven surface can be used directly, or a raised portion 5 can be added on a flat substrate surface, both of which have similar principles of changing the thickness of the liquid crystal layer 3 .

This embodiment does not limit the specific location of the protruding portion 5 , and it can be arranged on any one of the first substrate 1 or the second substrate 2 .

As an optional implementation in this embodiment, the raised portion 5 includes a plurality of protrusions 51 protruding toward the liquid crystal layer 3, and the protrusions 51 are made of a transparent material.

That is to say, the protruding part 5 is provided on the substrate in the form of a protruding 51. In the direction perpendicular to the substrate, the dimension of the protruding part is d0 (not marked in the drawings), and the liquid crystal at the position where the protruding part is not provided The thickness of the layer 3 is d1, and the thickness of the liquid crystal layer 3 at the position where the protrusion is set is d1-d0. Specifically, in order not to affect the light output of the display panel, the protrusion is made of a transparent material.

In this embodiment, the number of protrusions is not limited. As shown in FIG. 3 , only one protrusion can be provided in the area where a sub-pixel 6 is located as required, or as shown in FIG. 4 , it can be provided in the area where a sub-pixel 6 is located. The plurality of protrusions 51, the number of the protrusions 51 and the area of the protrusions (the area refers to the area of the orthographic projection of the protrusions to the substrate) can be changed according to the predetermined retardation. Specifically, when a plurality of protrusions are provided in the area where a sub-pixel is located, the plurality of protrusions are evenly distributed in the area where the sub-pixel is located.

In this embodiment, the specific size of the protrusion is not limited, and may be changed according to actual needs. Optionally, in a direction perpendicular to the substrate, the sizes of the protrusions corresponding to sub-pixels of different colors are different.

That is to say, the amount of phase retardation can be designed according to needs, and generally, protrusions of different sizes can be used, so that the liquid crystal layer 3 with different thicknesses can perform phase compensation for light in a predetermined wavelength range.

In one embodiment, the phase retarder includes a 1/2 wave plate and a 1/4 wave plate. Specifically, the 1/4 wave plate is arranged closer to the first substrate 1 than the 1/2 wave plate.

As shown in Figure 8, the incident light is polarized by the polarizer 7 and then converted into circularly polarized light through the 1/2 wave plate and 1/4 wave plate, and then enters the liquid crystal layer, and the incident circularly polarized light of a certain wavelength passes through the liquid crystal layer 3 1. After being reflected by the reflector 4, it still emits in the form of circularly polarized light, while the incident circularly polarized light of other wavelengths may become elliptically polarized light after passing through the liquid crystal layer, and its outgoing rate is relatively low. In order to improve the emission rate of a specific wavelength, the thickness of the liquid crystal layer is adjusted through the raised part provided in this application, and then the optical path difference of the light components in different polarization directions is adjusted, so that the elliptically polarized light is adjusted to circular polarization when it reaches the reflector 4 Light.

In one embodiment, in the direction perpendicular to the substrate, the dimension between the protrusion corresponding to the sub-pixel and the second substrate 2 is d, and the phase retardation Re of the liquid crystal layer 3 corresponding to the sub-pixel is =Δn*d, wherein, the liquid crystal layer 3 includes liquid crystal molecules, and Δn is the difference in refractive index between the long axis and the short axis of the liquid crystal molecules.

Taking Figure 5 as an example for illustration, the 1/2 wave plate and 1/4 wave plate are usually designed for the intermediate frequency band in visible light. It can be seen that the thickness of the liquid crystal layer 3 (also referred to as cell thickness) in the area marked d1 is relatively high, and the phase retardation Re=Δn*d1 of the liquid crystal layer 3 is relatively large. The output rate is relatively high, combined with Figure 9: light in the wavelength band near 650nm (such as red light) has a higher output rate at the position of retardation Re=300 (in Figure 9-11, the output rate refers to the output light and the incident light of the display panel. The ratio). Referring to FIG. 10 : light in a wavelength band around 450nm (for example, blue light) has a higher output rate at a position around retardation Re=200. Accordingly, the corresponding thickness d2 of the liquid crystal layer can be calculated. It can be seen that the phase retardation Re=Δn*d2 of the liquid crystal required for 450nm light is small, and the required cell thickness is relatively low. The liquid crystal layer 3 at this position selectively reflects the low-band light of the incident light, and the optimal retardation is set at The area of 180-220nm has a high emission rate for light in the wavelength band around 450nm. By controlling the proportion of d1 and d2 in a single pixel, the proportion of different wavelength bands in the reflected light can be adjusted to achieve the effect of adjusting the display color.

In the prior art, the thickness of the liquid crystal layer 3 at each position is constant, so that the output ratio and contrast of the liquid crystal layer 3 at each position to the visible light (380-780nm) of the whole band are very high, and the difference is small, so it cannot be adjusted. Shows what the effect does. However, in the reflective liquid crystal display panel of this embodiment, by adjusting the thickness of the liquid crystal layer 3 at different sub-pixel positions, the liquid crystal layer 3 corresponding to the sub-pixel has different phase retardation, thereby pre-determining the light of different wavelength ranges in the incident light. Phase compensation is equivalent to selectively reflecting incident light of different wavelengths, and reflecting incident light in a certain range of wavelengths to achieve the purpose of adjusting the display effect.

In another embodiment, as shown in FIG. 6 , the raised portion 5 is arranged on the side of the second substrate 2 close to the liquid crystal layer 3 , and the reflector 4 is arranged between the raised portion 5 and the liquid crystal layer 3 .

In this embodiment, the reflector 4 is arranged closer to the liquid crystal layer 3 than the raised portion 5, and the raised portion 5 has no influence on the propagation of light, so the material of the raised portion 5 is not limited in this embodiment, as long as it can It only needs to protrude toward the liquid crystal layer 3 . The specific number and size of the protruding parts 5 are similar to those in the accompanying drawings 3 and 4, and will not be repeated here.

In one embodiment, a color filter is provided between the first substrate 1 and the protrusion, and the color filter is integrated with the protrusion.

That is to say, in the direction perpendicular to the substrate, the sizes of the color filters of different colors are different, or the sizes of different positions of the color filters of the same color are different. It is equivalent to forming the color filter and the bumps with the same material as an integral structure. The advantage of this design is that the preparation process can be simplified.

In the drawings corresponding to the embodiments of the present disclosure, the sizes and thicknesses of the structural layers shown in the drawings are only for illustration. In process realization, the projected area of each structural layer on the substrate can be the same or different, and the required projected area of each structural layer can be realized through an etching process; at the same time, the structures shown in the drawings are not limited to each structural layer The geometric shape, for example, can be a rectangle as shown in the drawings, or a trapezoid, or other shapes formed by etching, which can also be realized by etching.

Example 3:

This embodiment provides a method for preparing the reflective liquid crystal display panel of the above embodiment, including the following preparation steps:

S01. Provide the first substrate; optionally, the first substrate is a color filter substrate, and the thickness of the color filter at different positions on the color filter substrate is different, that is, some positions of the color filter form protrusions, which is equivalent to the color filter having both The function of the protrusion.

S02. Provide a second substrate; optionally, the second substrate is an array substrate, and the reflector is formed on the array substrate. Specifically, this step includes the step of forming a reflector on the array substrate; the liquid crystal layer corresponding to some sub-pixels is The size in the direction perpendicular to the substrate is different from that of the liquid crystal layer corresponding to other sub-pixels in the direction perpendicular to the substrate, so that the liquid crystal layer corresponding to some sub-pixels has a phase retardation in a predetermined wavelength range.

In another embodiment, a raised portion can be formed on one of the substrates, wherein the raised portion can be formed on the same substrate as the reflector, and the raised portion is formed closer to the substrate than the reflector, thus forming the raised portion The material of the raised portion can be a transparent material or an opaque material, and the raised portion does not affect the reflected light of the reflector. If the raised portion and the reflector are respectively formed on two substrates, the material for forming the raised portion is selected from a transparent material.

S03 , forming a liquid crystal cell by facing the first substrate and the second substrate; forming a liquid crystal layer between the two substrates. The material of the liquid crystal layer may be nematic liquid crystal, smectic liquid crystal and cholesteric liquid crystal.

In this embodiment, various methods are used to make the color filter or the raised part occupy part of the position of the liquid crystal layer, which is equivalent to adjusting the thickness of the liquid crystal layer at different sub-pixel positions, so that the liquid crystal layer corresponding to the sub-pixel has different The amount of phase retardation, so as to perform predetermined phase compensation for light in different wavelength ranges in the incident light, which is equivalent to using liquid crystal layers of different thicknesses to selectively reflect incident light and reflect incident light in a certain range of wavelengths to achieve The purpose of adjusting the display effect.

Example 4:

This embodiment provides a display device, which includes any one of the above-mentioned reflective liquid crystal display panels, and a light source provided on the light emitting side of the reflective liquid crystal display panel. The display device may be any product or component with a display function such as a liquid crystal display panel, electronic paper, mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, navigator, and the like.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (9)

1. A reflective liquid crystal display panel, characterized in that it comprises an opposite first substrate and a second substrate, and a liquid crystal layer arranged between the first substrate and the second substrate, and the second A reflector is arranged on the substrate, and a polarizer and a phase retarder are arranged on the first substrate; wherein a raised portion is arranged on the side of the first substrate or the second substrate close to the liquid crystal layer, so that The thickness of the liquid crystal layer at the position where the raised portion is provided is different from the thickness of the liquid crystal layer at the position where the raised portion is not provided; The raised portion includes a plurality of protrusions protruding toward the liquid crystal layer, and a sub-pixel is correspondingly provided with a plurality of the protrusions; the plurality of protrusions corresponding to the same sub-pixel are evenly distributed in the area where the sub-pixel is located, and the plurality of protrusions are corresponding to the same sub-pixel. The protrusions are spaced apart; in the direction perpendicular to the substrate, the sizes of the protrusions corresponding to the sub-pixels of different colors are different; the number of the protrusions corresponding to the same sub-pixel is the same as that of the protrusions The orthographic projection area of the region where the sub-pixel is located is set according to the phase delay corresponding to the sub-pixel. 2. The reflective liquid crystal display panel according to claim 1, wherein the substrate close to the light-incident side is the first substrate, and the substrate far away from the light-incident side is the second substrate, and the raised portion is arranged on the first substrate. The side of the substrate close to the liquid crystal layer. 3. The reflective liquid crystal display panel according to claim 2, wherein the raised portion comprises a plurality of protrusions protruding toward the liquid crystal layer, and the protrusions are made of a transparent material. 4. The reflective liquid crystal display panel according to claim 3, wherein a color filter is provided between the first substrate and the protrusion. 5. The reflective liquid crystal display panel according to claim 3, characterized in that, in a direction perpendicular to the substrate, the dimension between the protrusion corresponding to the sub-pixel and the second substrate is d, and the The phase retardation of the liquid crystal layer corresponding to the sub-pixel is Re=Δn*d, wherein the liquid crystal layer includes liquid crystal molecules, and Δn is the difference in refractive index between the long axis and the short axis of the liquid crystal molecules. 6. The reflective liquid crystal display panel according to claim 1, wherein the raised portion is arranged on a side of the second substrate close to the liquid crystal layer, and the reflector is arranged between the raised portion and the liquid crystal layer . 7. The reflective liquid crystal display panel according to claim 2, wherein a polarizer is provided on a side of the first substrate facing away from the liquid crystal layer. 8. The reflective liquid crystal display panel according to claim 2, wherein the phase retarder comprises a 1/2 wave plate and a 1/4 wave plate. 9. A display device, characterized by comprising the reflective liquid crystal display panel according to any one of claims 1-8, and a light source provided on the light emitting side of the reflective liquid crystal display panel.