CN112981315A

CN112981315A - Black matrix forming method, display module and display device

Info

Publication number: CN112981315A
Application number: CN202110158644.3A
Authority: CN
Inventors: 陈锐冰
Original assignee: Huizhou Jufei Photoelectric Co ltd
Current assignee: Huizhou Jufei Photoelectric Co ltd
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2021-06-18

Abstract

The invention provides a black matrix forming method, a display module and a display device, wherein the black matrix forming method comprises the steps of placing a black target on a platform with a magnetic field; placing a target plate opposite to the black target material, wherein one surface of the target plate on which a black matrix is to be formed is opposite to the black target material; and covering a first area, corresponding to the light-emitting device, on the target plate by using a mask, and depositing a black target material on the surface of the target plate by magnetron sputtering to form a black matrix. The black matrix is formed through magnetron sputtering and a mask, the precision is high, the thickness of the formed black matrix can be thinner, the light transmittance can be lower, and the light emitting effect and the contrast of the display module can be ensured.

Description

Black matrix forming method, display module and display device

Technical Field

The invention relates to the field of display devices, in particular to a black matrix forming method, a display module and a display device.

Background

For a display screen such as a mini LED (sub-millimeter Light Emitting Diode) screen, in order to improve the contrast of display, black matrixes may be arranged on the surface of a circuit substrate or the surface of a protective colloid of a display module in ink-jet printing, silk-screen printing, spraying, coating and other manners, and the black matrixes effectively reduce crosstalk between different pixels and improve the contrast.

In some display module assemblies, thickness, the precision that black matrix formed all have the influence to the light-emitting angle of display module assembly, light-emitting uniformity even outward appearance etc. and along with the distance between the pixel is littleer and littleer in the display module assembly, the degree index of black matrix to the light-emitting effect influence of display module assembly rises.

Disclosure of Invention

The invention provides a black matrix forming method, a display module and a display device, and mainly solves the technical problems that: the traditional black matrix forming method has low precision and thick thickness.

In order to solve the above technical problems, the present invention provides a method for forming a black matrix, comprising placing a black target on a stage having a magnetic field;

placing a target plate opposite to the black target material, wherein one surface of the target plate on which a black matrix is to be formed is opposite to the black target material;

and covering a first area, corresponding to the light-emitting device, on the target plate by using a mask, and depositing the black target material on the surface of the target plate by magnetron sputtering to form a black matrix.

Optionally, the covering, by using a mask, a region of the target plate corresponding to the light emitting device, and depositing the black target material on the surface of the target plate by magnetron sputtering to form a black matrix includes:

respectively carrying out magnetron sputtering on the target plate for at least one time by using at least two different mask plates;

and after the magnetron sputtering is finished by using each mask plate, the black target material is deposited on the target plate except the first area.

Optionally, the covering, by using a mask, a region of the target plate corresponding to the light emitting device, and depositing the black target material on the surface of the target plate by magnetron sputtering to form a black matrix specifically includes:

arranging a first mask plate on the target plate, wherein the first mask plate covers the first area and the second area on the target plate;

sputtering the target plate to deposit the black target material on the target plate except the first area and the second area;

removing the first mask plate, and arranging a second mask plate on the target plate, wherein the second mask plate covers the first area and the third area on the target plate;

sputtering the target plate again to enable the black target material to be deposited on the target plate except the first area and the third area;

the second region does not overlap with the third region.

forming a mask layer on the target plate, wherein the mask layer covers the first area;

and carrying out magnetron sputtering on the target plate with the mask layer so as to deposit the black target material to the region of the target plate except the first region.

Optionally, the forming a mask layer on the target plate includes:

covering a mask material on one surface of the target board on which the black matrix is to be formed;

and removing the mask material in the region except the first region on the target plate to form the mask layer.

Optionally, the removing the mask material in the region of the target plate other than the first region includes:

arranging a third mask plate on the mask material, wherein the third mask plate covers the region outside the first region;

the mask material can be etched, the mask material of the first area is subjected to anti-etching treatment, and the mask material of the area except the first area is removed through etching; or, the mask material is a negative photoetching material, the mask material of the first region is exposed through the third mask plate, and the mask material of the region except the first region is removed through photoetching.

Optionally, the mask material has viscosity, and loses viscosity when a viscosity losing condition is met;

after the black matrix is formed on the target plate, the method further comprises the following steps:

and removing the mask layer.

Optionally, the condition of losing adhesion of the mask material includes at least one of:

reacting with target ions;

the temperature is higher than the target temperature;

is irradiated by the target light.

On the other hand, the invention also provides a display module, which comprises the black matrix, wherein the black matrix is formed by adopting the black matrix forming method.

On the other hand, the invention also provides a display device which comprises the display module.

Advantageous effects

The invention provides a black matrix forming method, a display module and a display device, wherein the black matrix forming method comprises the steps of placing a black target material on a platform with a magnetic field; placing a target plate opposite to the black target material, wherein one surface of the target plate on which a black matrix is to be formed is opposite to the black target material; the first area, corresponding to the light-emitting device, on the target plate is covered by the mask, the black target is deposited on the surface of the target plate through magnetron sputtering to form a black matrix, the black matrix with a thin thickness can be formed at high precision, the transmittance of the formed black matrix is low, and the light emitting effect and the contrast of the display module are guaranteed.

Drawings

Fig. 1 is a schematic flow chart illustrating a black matrix forming method according to a first embodiment of the present invention;

fig. 2 is a schematic view of the arrangement of a light emitting device provided in a first embodiment of the present invention;

FIG. 3 is a flowchart illustrating a process of thinning a black matrix forming method according to a second embodiment of the present invention;

fig. 4 is a schematic view illustrating a first mask plate disposed on a mini LED display module according to a second embodiment of the present invention;

fig. 5 is a first schematic structural diagram of a first mask according to a second embodiment of the present invention;

fig. 6 is a first schematic structural diagram of a second mask according to a second embodiment of the present invention;

fig. 7 is a second schematic structural diagram of a first mask according to a second embodiment of the present invention;

fig. 8 is a second schematic structural diagram of a second mask according to a second embodiment of the present invention;

FIG. 9 is a schematic view of a process for forming a mask layer on a mini LED display module according to a second embodiment of the present invention;

FIG. 10 is a schematic view of a second embodiment of the present invention for coating a masking material on an encapsulant of a mini LED display module;

fig. 11 is a schematic view of disposing a third mask on a negative photoresist according to a second embodiment of the present invention;

fig. 12 is a schematic structural view of a third mask according to a second embodiment of the present invention;

fig. 13 is a schematic diagram illustrating a mask layer formation according to a second embodiment of the present invention;

FIG. 14 is a schematic view of magnetron sputtering in a vacuum vessel according to a second embodiment of the present invention;

FIG. 15 is a schematic diagram illustrating a second embodiment of forming a black matrix;

FIG. 16 is a schematic view of a protective colloid disposed on a black matrix according to a second embodiment of the present invention;

wherein, 1 is a light emitting device; 2, packaging glue; 3 is a first mask plate; 4, a first rectangular hollow part; 5, a second rectangular hollow part; 6 is a negative photoetching material; 7 is a third mask plate; 8 is a vacuum container; 9 is a black target material; 10 is inert gas; 11 is a magnetic field; 12 is a positive ion; 13 is a black target molecule; 14 is a layer of black molecules; 15 is a black matrix; 16 is a protective colloid; 100 is a mini LED display module.

Detailed Description

In order that the contents of the present invention will be more readily understood, the present invention will now be described in further detail with reference to the accompanying drawings by way of specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The first embodiment is as follows:

the method aims to solve the problems that a black matrix formed by a traditional black matrix forming method is thick in thickness, low in precision and the like. The present embodiment provides a method for forming a black matrix, referring to fig. 1, the method for forming a black matrix includes:

s101, placing a black target on a platform with a magnetic field;

s102, placing a target plate and a black target material oppositely, wherein one surface of the target plate on which a black matrix is to be formed is opposite to the black target material;

s103, covering a first area, corresponding to the light-emitting device, on the target plate by using a mask, and depositing a black target material on the surface of the target plate through magnetron sputtering to form a black matrix.

The black target is a material for forming the black matrix, and includes, but is not limited to, carbon black, a metal light-absorbing material, and the like, which can effectively prevent light from passing through. It should be noted that the target board in this embodiment may include a substrate without a light emitting device or a sealant, or may be a display module or other cover plate with a light emitting device or a sealant already packaged therein. The black matrix may be formed on the substrate, or may be formed on other portions of the display module, such as the encapsulant, or in some embodiments, the black matrix may be formed on the cover plate (e.g., a glass cover plate) first, and then the cover plate is entirely covered on the display module encapsulated with the encapsulant, so that the black matrix can be covered on the light emitting device, thereby improving the contrast. The light Emitting device may be, but is not limited to, various types of LED chips, such as a mini LED chip, an OLED (organic light-Emitting Diode) chip, a micro LED (micro light-Emitting Diode) chip, and the like.

It is understood that the magnetron sputtering process is usually performed in vacuum, and the above-mentioned magnetic field platform and the target plate are all in a vacuum environment filled with inert gas (such as argon or other inert gas), and the incident ions can be generated by low-pressure inert gas glow discharge. And applying an electric field in a vacuum environment until the inert gas is broken down to ionize the electrons, wherein the electrons continuously impact gas molecules under the action of a magnetic field of a platform for placing the black target material to release more electrons, and the positive ions bombard the black target material after being impacted, so that the black target material molecules are sprayed onto a target plate to deposit a black target material molecular layer on the target plate. In this embodiment, the first region of the target plate corresponding to the light emitting device is covered by the mask, so that the black matrix is formed on the target plate, and no black target molecules are deposited in the first region corresponding to the light emitting device, so that light of the light emitting device can penetrate through the first region. The above-described manner is merely an example of magnetron sputtering, and other manners may also be used to realize magnetron sputtering.

In the black matrix forming method of this embodiment, the black target is deposited on the surface of the target plate by magnetron sputtering to form the black matrix, and the thickness of the black target molecule layer may be formed very thin, for example, in some implementation processes, the thickness of the black matrix formed by magnetron sputtering may be 200 nm, while the minimum thickness of the black matrix formed by conventional ink-jet printing, screen printing, spraying, coating, and the like is about 50 μm. Meanwhile, the accuracy of magnetron sputtering is high, so that the dimensional accuracy of the black matrix can be controlled to be below 10 nanometers. Moreover, the black target material molecular layer has compact molecular composition and low transmittance, can be blackened as far as possible, and the light transmittance in some implementation processes can be less than 5%. The light-emitting angle of the display module assembly is guaranteed to the thinner thickness of black matrix, the uniformity of the appearance uniformity of the display module assembly and the light-emitting uniformity of the pixels is guaranteed to the higher precision, and the contrast of the display module assembly during displaying is guaranteed to the lower transmittance.

In practical application, because the light emitting devices on the display module are small in size and large in number, if an independent mask is arranged for each light emitting device, the mask is difficult to set and complicated and is difficult to remove. Therefore, in order to more efficiently form the black matrix, in some embodiments, masking a region of the target plate corresponding to the light emitting device with a mask, and depositing a black target material onto a surface of the target plate by magnetron sputtering to form the black matrix includes:

and after the magnetron sputtering is finished by using each mask plate, black target materials are deposited on the target plate except the first area.

It can be understood that each mask plate in this embodiment covers the first area, and no black target material is deposited in the first area in any magnetron sputtering process.

In at least two different masks of this embodiment, the set of regions that are not masked includes all regions except the first region. Therefore, when the magnetron sputtering is completed using each mask, the black target is deposited in the regions other than the first region.

The material of the mask plate can be any material which is not easy to deform, and the mask plate can be repeatedly used. In some specific implementation processes, the mask plate can be processed by laser, and the material of the mask plate can be easily processed by laser. In this embodiment, the mask plate may be formed by laser processing using a steel sheet.

Because magnetron sputtering is carried out for each mask plate once, in order to reduce the times of magnetron sputtering, improve the production efficiency and control the cost, the total number of the mask plates can be reduced as much as possible. In some embodiments, the forming the black matrix by masking a region of the target plate corresponding to the light emitting device with a mask and depositing a black target material on the surface of the target plate by magnetron sputtering specifically includes:

arranging a first mask plate on the target plate, wherein the first mask plate covers a first area and a second area on the target plate;

removing the first mask plate, arranging a second mask plate on the target plate, and covering a first area and a third area on the target plate by the second mask plate;

sputtering the target plate again to deposit the black target material on the target plate except the first area and the third area;

the second region does not overlap with the third region.

It can be understood that, as shown in fig. 2, since the light emitting devices 1 are arranged at intervals, the first regions corresponding to the light emitting devices 1 are separated, and if a single mask plate is to completely cover the first regions, there are inevitably portions (second regions) connecting the first regions, and therefore, the black matrix cannot be manufactured by a single magnetron sputtering. The first mask plate and the second mask plate are used alternately, the second mask plate does not cover a second area in the first mask plate, the second area which cannot be deposited to the black target material during first magnetron sputtering is exposed, black target material deposition to the second area is completed during second magnetron sputtering, all areas except the first area are deposited with the black target material, and a black matrix is formed. Two mask plates are adopted, magnetron sputtering is only needed to be carried out twice, the efficiency is improved, and the cost is controlled.

In other embodiments, a mask layer covering only the first region may be directly formed on the target plate, and magnetron sputtering may be performed on the target plate on which the mask layer is formed, so that the black target may be deposited on a region of the target plate other than the first region to form a black matrix at one time, thereby further reducing the number of times of magnetron sputtering. And it can be understood that single magnetron sputtering is easier to control, and the formed black matrix has better uniformity. Compared with the method that the independent mask is directly placed in the first area, the method that the mask layer is directly formed on the target board is more convenient and easier to implement.

In some embodiments, the forming of the mask layer on the target plate may include forming the mask layer by covering a mask material on a side of the target plate on which the black matrix is to be formed, and removing the mask material in a region other than the first region. The mask material is removed by means including, but not limited to, etching, photolithography.

Removing the mask material of the region of the target plate other than the first region includes disposing a third mask plate on the mask material, the third mask plate covering the region of the target plate other than the first region.

After the third mask plate is arranged, only the mask material of the first area is exposed, so that the mask material of the first area is processed, and cannot be removed in the subsequent steps. In one example, the mask material may be selected from etchable materials, the mask material in the first region is subjected to an etching-resistant treatment, such as coating a protective layer, or is doped with ions capable of resisting etching, and after removing the third mask plate, the mask material in the remaining region is removed by etching, and only the mask material in the first region remains to form the mask layer. In another example, the mask material may be a negative photoresist material, the mask material in the first region may be irradiated by light because the mask material in the first region is exposed by the third mask plate, the negative photoresist material may not be dissolved in the developing solution after being exposed (i.e., the photoresist is selectively irradiated by light with a specific wavelength), and after the third mask plate is removed, the mask material in the remaining region may be washed away by the developing solution to form the mask layer.

In some embodiments, the masking material has a tack property and can lose its tack property when a tack-free condition is satisfied, and after the black matrix is formed, the masking layer can be made to lose its tack property and removed. The de-sticking condition of the masking material may include at least one of:

reacting with target ions;

the temperature is higher than the target temperature;

is irradiated by the target light.

The mask material of the mask layer can be removed by losing the viscosity through plasma wind, temperature rise and illumination of target light.

In the black matrix forming method of the present embodiment, a black target is placed on a stage having a magnetic field; the target plate and the black target material are oppositely placed, the black target material is deposited on the surface of the target plate through a mask and a magnetron sputtering mode on the surface of the target plate, the formed black matrix is thin in thickness, high in precision and low in transmittance, and the light emitting effect and the contrast of the display module are guaranteed.

Example two:

in order to better explain the black matrix forming method of the present invention, the present embodiment is further explained with reference to the drawings and the specific forming process, please refer to fig. 3, which is a detailed flowchart of the black matrix forming method provided in the present embodiment. In this embodiment, a target board is taken as an example of a mini LED display module, where the mini LED display module includes a substrate, a light emitting device array disposed on the substrate, and an encapsulant for encapsulating and protecting the light emitting device.

S201, arranging a first mask plate on the mini LED display module, and placing the mask plate into a vacuum container;

as shown in fig. 4, a first mask 3 is disposed on the encapsulation glue 2, and the first mask 3 covers a first region and a second region of the mini LED display module.

S202, placing a black target on a platform with a magnetic field;

s203, enabling the surface, provided with the packaging glue, of the mini LED display module to face the black target material;

s204, injecting inert gas into the vacuum container;

it should be noted that the execution order of the above steps S201 to S204 can be adjusted without conflict.

S205, applying an electric field in the vacuum container to enable the inert gas to be broken down and ionized to generate electrons;

s206, removing the first mask plate, arranging a second mask plate on the mini LED display module, and placing the second mask plate into the vacuum container again;

s205, after one-time magnetron sputtering is finished, the mini LED display module is taken out, and the first mask plate is replaced by a second mask plate. The second mask plate covers the first region and the third region on the target plate, and the second region and the third region are not overlapped.

S207, carrying out magnetron sputtering on the mini LED display module provided with the second mask plate;

performing magnetron sputtering on the mini LED display module provided with the second mask plate is consistent with the steps S203, S204 and S205.

And after the second magnetron sputtering is finished, removing the second mask plate to obtain the mini LED display module with the black matrix.

Fig. 5 is a structure of an exemplary first mask, and fig. 6 is a structure of an exemplary second mask corresponding to the first mask of fig. 6, where in fig. 5 and 6, a black area is an area covered by the mask, and a white area is a hollow area. The first mask plate covers the first area corresponding to the area A of the first area, and the area B corresponding to the second area is connected with each row of areas A, so that the first mask plate is kept in an integral state (the frame of the first mask plate is not shown); the rest areas of the first mask plate are hollow, so that black target molecules can pass through. Corresponding to the first mask plate, the second mask plate is only hollowed at the position of a second area connected with each row of first areas. And the first mask plate and the second mask plate are alternately used, so that black target molecules are deposited in all regions except the first region on the mini LED display module to form a black matrix.

Referring to fig. 7 and 8, the present embodiment further provides another exemplary first mask plate and second mask plate, in fig. 7 and 8, a region a filled with black oblique lines and black filling is a region covered by the mask plate, and a white region is a hollow region, where the black filled region a corresponds to a first region of the mini LED chip (fig. 7 and 8 only draw a part of the black filled region a as an example of a position of the mini LED chip, in practical applications, the mini LED chip may be fully or almost fully distributed with the mini LED display module). Including the first rectangle fretwork 4 that each row was crisscross to be arranged on the first mask plate, the width of first rectangle fretwork 4 equals the interval between two horizontal mini LED chips, highly equals the interval between two vertical mini LED chips of the height that highly equals two mini LED chips plus, and every first rectangle fretwork 4 is located between two vertical mini LED chips, and the upper and lower both sides align with the upper and lower limit of two vertical adjacent mini LED chips respectively. Including each second rectangle fretwork 5 of arranging in a staggered way on the second mask board, the width of second rectangle fretwork 5 equals the width of two mini LED chips plus the interval between two horizontal mini LED chips, highly equals the interval between two fore-and-aft mini LED chips of two mini LED chips, every second rectangle fretwork 5 is located between two horizontal lines of mini LED chips, and control both sides and align with the left and right sides of two horizontal adjacent mini LED chips respectively. By alternately using the first mask plate and the second mask plate in the example, black target molecules can be deposited on all regions except the first region on the mini LED display module to form a black matrix.

The two examples are only two optional mask setting modes, and in practical application, the form of the mask can be selected at will, and more mask numbers can be used as long as a black matrix can be formed.

In this embodiment, a mask layer formed on the mini LED display module is further described in detail with reference to specific examples, with reference to fig. 9, the step of forming the mask layer includes:

s301, arranging a mask material on the mini LED display module;

referring to fig. 10, a mask material, in this example, a negative photoresist material 6, is coated on the encapsulation glue 2 of the mini LED display module, and the negative photoresist material 6 includes, but is not limited to, a negative photoresist or other negative photoresist material that can be processed by photolithography.

S302, arranging a third mask plate on the negative photoetching material;

as shown in fig. 11 and 12, fig. 11 illustrates a cross-sectional structure diagram of disposing a third mask 7 on the negative-tone lithography material 6, and fig. 12 is a schematic structural diagram of the third mask 7, in which a region filled with black oblique lines is a region covered by the third mask 7, the third mask exposes only the negative-tone lithography material 6 in the first region, and the rest regions are completely covered.

S303, patterning the negative photoetching material;

the patterning includes irradiating the negative resist 6 with a specific light (exposure), and removing the negative resist 6 not irradiated with the specific light using a developer (development). As shown in fig. 13, since the third mask exposes only the negative photoresist 6 in the first region, after exposure and development, only the negative photoresist 6 in the first region remains to form a mask layer.

Referring to fig. 14, in the vacuum chamber 8, the mini LED display module 100 is disposed opposite to the black target 9, and the vacuum chamber 8 is filled with an inert gas 10. After the electric field E is applied, electrons E continuously impact gas molecules under the action of the magnetic field 11 of the platform for placing the black target 9, more electrons E are released, positive ions 12 bombard the black target 9 after being impacted, the black target molecules 13 are sputtered onto the mini LED display module 100, and a black molecular layer 14 is deposited on the surface of the mini LED display module 100. The black molecule layer 14 is deposited on the area of the mini LED display module 100 not covered by the mask layer, and the black target molecules 13 sputtered to the first area and the second area are blocked by the mask layer formed by the negative photoetching material 6.

Referring to fig. 15, after the black matrix 15 is formed by magnetron sputtering, the negative photoresist remaining on the first region is removed. In practical application, as shown in fig. 16, after the black matrix 15 is formed, a layer of protective colloid 16 may be further disposed on the black matrix to protect the black matrix 15.

If the mask material is a material that can be processed by etching, in step S303, the first region can be retained during the etching process by applying a protective layer or a process of ion plasma etching resistance doped with an etching resistance, so as to form a mask layer.

Example three:

the present embodiment provides a display module, which includes a black matrix formed by the black matrix forming method in the first embodiment and the second embodiment. For example, the black matrix may be formed on a substrate of the display module, an encapsulant of the display module, or a cover plate of the display module. The display module can be, but is not limited to, a mini LED display module, an OLED display module, a micro LED display module, etc.

The embodiment provides a display device, which includes the above display module, the display device provided in the embodiment can be applied to various light emitting fields, for example, it can be applied to various display fields (such as a television, a display, a mobile phone, etc.), and the display module can include, for example, an LED display panel, a mini LED display panel, a micro LED display panel, etc. The applications described above are only a few applications exemplified by the present embodiment, and it should be understood that the applications of the display device in the present embodiment are not limited to the fields exemplified above.

It should be noted that the number, shape, and relationship of sizes of the elements in the drawings are not to indicate the actual condition of the elements unless otherwise specified, but are merely schematic diagrams for easy understanding. While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A black matrix forming method, comprising:

placing the black target material on a platform with a magnetic field;

2. The method of forming the black matrix of claim 1, wherein the masking a region of the target plate corresponding to the light emitting device with a mask and depositing the black target material onto the surface of the target plate by magnetron sputtering to form the black matrix comprises:

3. The method of claim 2, wherein the masking a region of the target plate corresponding to the light emitting device with a mask and depositing the black target material on the surface of the target plate by magnetron sputtering to form the black matrix comprises:

the second region does not overlap with the third region.

4. The method of forming the black matrix of claim 1, wherein the masking a region of the target plate corresponding to the light emitting device with a mask and depositing the black target material onto the surface of the target plate by magnetron sputtering to form the black matrix comprises:

5. The black matrix forming method of claim 4, wherein the forming of the mask layer on the target plate comprises:

6. The black matrix forming method of claim 5, wherein the removing the mask material of the region of the target plate other than the first region comprises:

7. The black matrix forming method of claim 5, wherein the mask material has viscosity, and loses viscosity when a non-stick condition is satisfied;

and removing the mask layer.

8. The black matrix forming method of claim 7, wherein the de-sticking condition of the mask material comprises at least one of:

reacting with target ions;

the temperature is higher than the target temperature;

is irradiated by the target light.

9. A display module comprising a black matrix formed by the method according to any one of claims 1 to 8.

10. A display device, characterized in that the display device comprises the display module according to claim 9.