CN117991529A

CN117991529A - Display device

Info

Publication number: CN117991529A
Application number: CN202211325489.0A
Authority: CN
Inventors: 李富琳; 孙路祥
Original assignee: Hisense Visual Technology Co Ltd
Current assignee: Hisense Visual Technology Co Ltd
Priority date: 2022-10-27
Filing date: 2022-10-27
Publication date: 2024-05-07

Abstract

The invention discloses a display device, comprising: the display panel and the backlight module are positioned on the light incident side of the display panel. The backlight module comprises a lamp panel, wherein the lamp panel comprises a circuit board and a light emitting device positioned on the circuit board. The light reflecting part is arranged between the circuit board and at least part of the light emitting devices, so that the light emitted from the bottom of the part of the light emitting devices is incident below the light emitting devices and then projected in the light emitting direction again after being reflected by the light reflecting part, and the light emitting efficiency of the lamp panel is greatly improved.

Description

Display device

Technical Field

The invention relates to the technical field of display, in particular to a display device.

Background

Compared with the traditional display technology, the High-DYNAMIC RANG (HDR) display technology can provide more dynamic expression and image details, can better reflect the free visual effect of objects in the real environment, and is widely considered to cause the next revolution in the display field. Meanwhile, the HDR technology also puts higher demands on the liquid crystal display terminal-finer partition control and higher image contrast.

Mini LEDs (MINI LIGHT EMITTING Diode, simply Mini LEDs) have become a current research hotspot in liquid crystal displays as backlights. Different from the traditional backlight scheme that the light guide plate is adopted for the liquid crystal display, a huge amount of Mini LEDs are adopted as backlight sources to be applied to the field of backlight, so that the light and thin backlight can be realized, finer regional dimming control can be realized, and the dynamic contrast of the liquid crystal display is improved.

However, the Mini LED has many problems in application design, a part of emergent light of the Mini LED panel is directly projected to the display panel, and a part of light incident below the Mini LED is absorbed by the panel and cannot be effectively utilized, so that the utilization rate of the light source is low.

Disclosure of Invention

In a first aspect of an embodiment of the present invention, there is provided a display device including:

A display panel for displaying an image;

the backlight module is positioned on the light incident side of the display panel and is used for providing backlight; the backlight module comprises a lamp panel; the lamp plate includes:

A circuit board for providing a driving signal;

The light emitting devices are positioned on the circuit board and are electrically connected with the circuit board;

The light reflecting parts correspond to at least part of the light emitting devices, one light reflecting part corresponds to one light emitting device, and the light reflecting parts are positioned between the corresponding light emitting devices and the circuit board.

In the display device provided by the embodiment of the invention, the light reflecting part is arranged between at least part of the light emitting devices and the circuit board, so that the light emitted from the light emitting devices to the bottom is reflected by the light reflecting part and then projected in the light emitting direction again after entering one side of the circuit board, and the light emitting efficiency of the lamp panel is greatly improved.

In some embodiments of the present invention, the number of light reflecting portions is equal to the number of light emitting devices; the front projection of the light reflecting part on the circuit board and the front projection of the light emitting device on the circuit board have an overlapping area.

In some embodiments of the present invention, a surface of the circuit board facing the light emitting device has a plurality of grooves; one groove corresponds to one light reflecting part, and the light reflecting part is positioned in the corresponding groove.

In some embodiments of the invention, a light emitting device includes a first electrode and a second electrode;

The circuit board comprises:

A substrate;

the circuit layer is positioned on one side of the substrate facing the light-emitting device; the circuit layer comprises a plurality of pad pairs; a pad pair including a first pad and a second pad; one bonding pad pair corresponds to one light emitting device, a first bonding pad in the bonding pad pair is connected with a first electrode of the light emitting device, and a second bonding pad in the bonding pad pair is connected with a second electrode of the light emitting device;

The solder mask layer is positioned on one side of the circuit layer, which is away from the substrate; the solder mask layer comprises a plurality of windows; a window for exposing a pad pair;

The first bonding pad and the second bonding pad in the bonding pad pair exposed through windowing are separated by a set distance, and the light reflecting part is located between the first bonding pad and the second bonding pad.

In some embodiments of the present invention, a surface of a side of the substrate facing the circuit layer includes a plurality of concave portions, the concave portions being located between the first bonding pad and the second bonding pad; the concave part is used for forming a groove, so that the thickness of the reflecting part can be increased, and the reflecting efficiency is improved.

In some embodiments of the present invention, the surface of the light reflecting portion facing the light emitting device is not higher than the surface of the bonding pad facing the light emitting device, so as to avoid poor welding caused by too high light reflecting portion.

In some embodiments of the present invention, the reflective portion and the solder mask are made of white ink, and the solder mask can reflect light to further improve the radiation efficiency.

In some embodiments of the invention, the thickness of the solder mask layer is 20-30 μm, so that poor welding is avoided; the thickness of the light reflecting part is larger than that of the solder mask layer, so that the light reflecting part has enough thickness to reflect more light.

In some embodiments of the present invention, the backlight module further includes: the reflecting sheet is positioned on one side of the circuit board close to the light emitting device; the reflector sheet comprises a plurality of openings; the opening is used for exposing a part of the solder mask adjacent to the light emitting device.

In some embodiments of the present invention, the light emitting device is a Mini LED chip, the size of which is less than 500 μm.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic cross-sectional structure of a display device according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional structure of a backlight module according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a lamp panel according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a cross-sectional structure of a lamp panel according to an embodiment of the present invention;

Fig. 5 is a schematic cross-sectional structure of a Mini LED lamp panel in the related art;

FIG. 6 is a third schematic cross-sectional view of a lamp panel according to an embodiment of the present invention;

Fig. 7 is a schematic top view of a lamp panel according to an embodiment of the invention;

FIG. 8 is a schematic diagram of a cross-sectional structure of a lamp panel according to an embodiment of the present invention;

Fig. 9 is a flowchart illustrating a method for manufacturing a display device according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a manufacturing process of a display device according to an embodiment of the present invention;

FIG. 11 is a second schematic diagram illustrating a manufacturing process of the display device according to the embodiment of the invention;

FIG. 12 is a third schematic diagram illustrating a manufacturing process of the display device according to the embodiment of the invention;

FIG. 13 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the invention;

FIG. 14 is a schematic diagram of a manufacturing process of a display device according to an embodiment of the present invention;

FIG. 15 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the present invention;

FIG. 16 is a schematic diagram of a manufacturing process of a display device according to an embodiment of the invention;

FIG. 17 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the invention;

fig. 18 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the invention.

The LED backlight module comprises a 100-backlight module, a 200-display panel, an 11-backboard, a 12-lamp panel, a 121-circuit board, a 122-light-emitting device, a 123-light reflecting part, a 13-reflecting sheet, a 14-diffusion plate, a 15-optical film, an H-groove, L1, L2, L3, L4-light rays, a 1211-substrate, a 1212-circuit layer, a 1213-solder mask layer, a 1221-first electrode, a 1222-second electrode, an A-first bonding pad, a B-second bonding pad, S-solder paste, a K1-fracture, a K2-window, a K3-concave part, a K4-opening and an M-metal lead.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a further description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. However, the exemplary embodiments can 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 the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present invention are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present invention. The drawings of the present invention are merely schematic representations of relative positional relationships and are not intended to represent true proportions.

The LCD is mainly composed of a backlight module and an LCD panel. The liquid crystal display panel does not emit light and needs to realize brightness display by means of a light source provided by the backlight module.

The display principle of LCD is to put liquid crystal between two pieces of conductive glass, and drive the electric field between two electrodes to cause the electric field effect of liquid crystal molecule distortion to control the transmission or shielding function of backlight source, so as to display the image. If a color filter is added, a color image can be displayed.

Fig. 1 is a schematic cross-sectional structure of a display device according to an embodiment of the present invention.

Referring to fig. 1, the display device includes: a backlight module 100 and a display panel 200.

The display panel 200 is located on the light emitting side of the backlight module 100, and the shape and size of the display panel are generally matched with those of the backlight module, and in general, the display panel 200 may be configured as a rectangle including a top side, a bottom side, a left side and a right side, wherein the top side is opposite to the bottom side, the left side is opposite to the right side, the top side is connected to one side of the left side and one side of the right side respectively, and the bottom side is connected to the other side of the left side and the other side of the right side respectively.

The display panel 200 is a transmissive display panel, and is capable of modulating the transmittance of light, but does not emit light itself. The display panel 200 has a plurality of pixel units arranged in an array, and each pixel unit can independently control the transmittance and color of the light incident on the pixel unit by the backlight module 100, so that the light transmitted by all the pixel units forms a displayed image.

In an embodiment of the present invention, the display panel 200 may be a liquid crystal display panel.

The backlight module 100 is generally located at the bottom of the display device, and its shape and size are adapted to those of the display device. When applied to the fields of televisions, mobile terminals and the like, the backlight module generally adopts a rectangular shape.

The backlight module in the embodiment of the invention adopts the direct type backlight module and is used for uniformly emitting light in the whole light-emitting surface and providing light with sufficient brightness and uniform distribution for the display panel so that the display panel can normally display images.

Fig. 2 is a schematic cross-sectional structure of a backlight module according to an embodiment of the invention.

Referring to fig. 2, the backlight module includes: a back plate 11, a lamp panel 12, a reflecting sheet 13, a diffusion plate 14 and an optical film 15.

The back plate 11 is located at the bottom of the backlight module and has supporting and bearing functions. The back plate 11 is typically a rectangular structure, the shape of which is adapted to the shape of the display device when applied to a shaped display device. The back plate 11 includes a top side, a bottom side, a left side, and a right side. Wherein the sky side is relative with the earth side, and left side is relative with the right side, and the sky side links to each other with one end of left side and one side of right side respectively, and the earth side links to each other with the other end of left side and the other end of right side respectively.

The back plate 11 is made of aluminum, iron, aluminum alloy or iron alloy. The back plate 11 is used for fixing the lamp plate 12 and supporting and fixing the edge positions of the reflecting sheet 13, the diffusing plate 14, the optical film 15 and other parts, and the back plate 11 also plays a role in heat dissipation of the lamp plate 12.

In the embodiment of the invention, the backlight module is a direct type backlight module, and the lamp panel 12 is located on the back plate 11. Generally, the lamp panel 12 may have a square or rectangular shape as a whole, and the shape and size of the lamp panel are adapted to the shape and size of the display device when the lamp panel is applied to the special-shaped display device.

A plurality of light panels 12 may be provided according to the size of the display device, and backlight is commonly provided between the light panels 12 by a stitching manner. In order to avoid the optical problem caused by the splicing of the lamp panels 12, the splice between the adjacent lamp panels 12 is made as small as possible, and even seamless splicing is realized.

The lamp panel 12 may use a light emitting device 122 such as a light emitting Diode (LIGHT EMITTING Diode, abbreviated as LED), mini LED, or a laser chip as a backlight source. Compared with the traditional LED, the Mini LED has smaller size, can realize more refined dynamic control, and improves the dynamic contrast of the display device.

The reflecting sheet 13 is positioned above the lamp panel 12 in the same shape as the lamp panel 12, and is generally rectangular or square. Since metal has high reflectivity, the reflective sheet 13 can be made of a metal material in the embodiment of the present invention. For example, silver, magnesium, aluminum, platinum, copper, or an alloy of any one or more of them. Alternatively, the reflection sheet 13 may be formed by coating a reflective material on the surface of the base material, and is not limited thereto.

The reflective sheet 13 includes a plurality of openings for exposing the light emitting devices 122. The reflective sheet 13 is disposed above the lamp panel 12 to expose each light emitting device 122, so as to ensure that the light emitting device 122 can emit light smoothly. The reflective sheet 13 has a property of reflecting light, so that light emitted from the lamp panel 11 to the back plate side or light reflected back to the back plate side by an element in the backlight module can be reflected back to the light emitting side by the reflective sheet 13, thereby improving the utilization efficiency of the light source.

The diffusion plate 14 is located on the light emitting side of the lamp panel 12 at a certain distance from the reflection sheet 13, and the shape of the diffusion plate 14 is the same as the shape of the lamp panel 12. The diffuser plate 14 may be generally rectangular or square in configuration.

The diffuser plate 14 is used to scatter incident light so that the light passing through the diffuser plate 14 is more uniform. The diffusion plate 14 is provided with a scattering particle material, and light rays are incident on the scattering particle material and are continuously refracted and reflected, so that the effect of scattering the light rays is achieved, and the effect of homogenizing the light is achieved.

The thickness of the diffusion plate 14 is 1.5mm-3mm, the diffusion plate has higher haze and better uniformity, and the diffusion plate 14 can be processed by adopting an extrusion process, and the material used by the diffusion plate 14 is at least one selected from polymethyl methacrylate PMMA, polycarbonate PC, polystyrene PS and polypropylene PP.

The optical film 15 is located on the side of the diffusion plate 14 facing away from the reflective sheet 13, and the optical film 15 is disposed in a whole layer, and has the same shape as the lamp panel 12, and may be generally rectangular or square.

The optical film 15 can adapt the backlight module to various practical applications.

In the embodiment of the present invention, the light emitting device 122 in the lamp panel 12 may be a blue LED or a blue Mini LED, and the optical film 15 includes a quantum dot layer or a fluorescent layer.

The quantum dot layer comprises a red quantum dot material and a green quantum dot material, the red quantum dot material emits red light under the excitation of blue light, the green quantum dot material emits green light under the excitation of blue light, and the excited red light, the excited green light and the transmitted blue light are mixed into white light for emitting.

The fluorescent layer comprises a fluorescent material for stimulated emission of red light and stimulated emission of green light, and the stimulated emission of the red light, the green light and the transmitted blue light are mixed into white light for emission.

In the embodiment of the present invention, the light emitting device 122 may also include a red light emitting device, a green light emitting device, and a blue light emitting device, which are not limited herein.

In addition, the optical film 15 may further include a prism sheet that can change an outgoing angle of light, thereby changing a viewable angle of the display device.

The optical film 15 may further include a reflective polarizer, which is used as a brightness enhancing sheet, so as to enhance the brightness of the backlight module, enhance the light utilization efficiency, and simultaneously make the outgoing light have polarization properties, so as to omit the use of the polarizer under the liquid crystal display panel.

In the embodiment of the present invention, as shown in fig. 2, the lamp panel 12 includes a circuit board 121 and a plurality of light emitting devices 122 disposed on the circuit board 121.

The circuit board 121 is located above the back plate 11, and the shape of the circuit board 121 is the same as the overall shape of the lamp panel 12. In general, the circuit board 121 has a plate shape, and is rectangular or square in its entirety.

The circuit board 121 is usually closely attached to the back plate 11, and the back plate 11 supports and fixes the circuit board 121, so that the circuit board 121 is always stable in the use process, and the back plate 11 also plays a role in heat dissipation of the circuit board 121, so that expansion deformation of the circuit board 121 due to heat is reduced.

The light emitting device 122 is located on a side of the circuit board 121 facing away from the back plate 11.

The light rays emitted by the light emitting device 122 are distributed in a lambertian body, the utilization rate of the light rays is ensured by the reflecting sheet 13 in the current direct type backlight module, as shown in fig. 2, a part of the light rays L1 emitted by the light emitting device 122 are transmitted through the diffusion plate 14 and the optical film 15 and then are directly projected to the display panel; part of the light L2 is reflected back to the lamp panel 12 through the diffusion plate 14 and the optical film 15, and is projected towards the display panel again after being reflected by the reflecting sheet 13; a part of the light L3 is directly incident on the reflective sheet 13, reflected by the reflective sheet 13, and projected in the direction of the display panel.

However, since the reflective sheet is not disposed at the contact position between the light emitting device 122 and the circuit board 121, most of the light incident on the light emitting device 122 is absorbed by the circuit board 121 in the conventional direct type backlight module, and thus cannot be effectively utilized.

Because the size of the light emitting device 122 is smaller, especially the Mini LED is usually within 500 μm, the light emitting device 122 is densely arranged on the circuit board 121, which results in a larger area where the light panel 12 cannot reflect light, and the light utilization rate is small, thus reducing the light extraction efficiency of the light panel.

In view of this, in the display device provided by the embodiment of the invention, as shown in fig. 2, a plurality of reflective portions 123 are disposed on the surface of the circuit board 121 near the light emitting device 122 for reflecting light. One light reflecting part 123 corresponds to one light emitting device 122, and the light reflecting part 123 is positioned between the corresponding light emitting device 122 and the circuit board 121, so that part of light L4 emitted to the bottom by the light emitting device 122 arranged on the light reflecting part 123 is incident to one side of the circuit board 121 and then is reflected by the light reflecting part 123 to be projected in the light emitting direction again, and the light emitting efficiency of the lamp panel is greatly improved.

In particular, the overlapping area exists between the front projection of the light reflecting portion 123 on the circuit board 121 and the front projection of the light emitting device 122 on the circuit board 121, so that the light reflecting portion 123 can effectively reflect the light incident from the light emitting device 122 to the bottom of the light emitting device. When the front projection of the light emitting device 122 on the circuit board 121 is completely located in the front projection of the light reflecting portion 123 on the circuit board 121, the light emitting efficiency of the lamp panel can be improved to the greatest extent.

In some embodiments, the number of the light reflecting portions 123 is equal to the number of the light emitting devices 122, so that all the light emitting devices 122 can be correspondingly disposed on the light reflecting portions 123 to improve the overall light emitting efficiency of the lamp panel.

Fig. 3 is a schematic cross-sectional structure of a lamp panel according to an embodiment of the invention.

In some embodiments, as shown in fig. 3, a surface of the circuit board 121 facing the light emitting device 122 side has a plurality of grooves H; one groove H corresponds to one light reflecting portion 123, and the light reflecting portion 123 is located in the corresponding groove H. By providing the groove H, the thickness of the light reflecting portion 123 can be adjusted by adjusting the depth of the groove H, and the problem of poor welding of the light emitting device due to the excessive thickness of the light reflecting portion 123 can be avoided.

Fig. 4 is a schematic diagram of a cross-sectional structure of a lamp panel according to an embodiment of the invention.

In the embodiment of the present invention, the light emitting device 122 may use Mini LEDs. The Mini LED can be a Mini LED with a forward-mounted structure, a Mini LED with a flip-chip structure or a Mini LED with a vertical structure. As shown in fig. 4, a Mini LED in a flip-chip configuration is illustrated.

Both electrodes of the Mini LED with the flip-chip structure are positioned on one side away from the light emitting surface. The circuit board 121 is used to provide driving electrical signals for the Mini LEDs. The Mini LED and the circuit board 121 are manufactured separately, the surface of the circuit board 121 comprises a plurality of bonding pads for welding the Mini LED, the Mini LED is transferred to the upper part of the bonding pad after being manufactured, and the electrode of the Mini LED is welded on the bonding pad of the circuit board 121 through the processes of reflow soldering and the like, so that the Mini LED can be driven to emit light through the input signal of the control circuit board 121.

In particular, the circuit board 121 may be a printed circuit board (Printed Circuit Board, abbreviated as PCB). As shown in fig. 4, the circuit board 121 includes: a substrate 1211, a wiring layer 1212, and a solder resist layer 1213.

The substrate 1211 of the circuit board 121 may be made of FR4, aluminum-based, glass, or the like. Or the substrate 1211 of the circuit board 121 may be made of a flexible material to form a flexible display device. When the substrate 1211 is made of a metal material such as aluminum, heat dissipation performance of the circuit board 121 can be improved.

The circuit layer 1212 is deposited on the substrate 1211 by electroplating with a conductive material, and the conductive material is etched as needed to form a circuit pattern. The material used for the wiring layer 1212 may be copper.

In some embodiments, the substrate 1211 may be formed of a base material and an adhesive layer covering the surface of the base material. Wherein the substrate may be made of FR4, aluminum-based, or glass, or the substrate may be made of a flexible material to form a flexible display device. The adhesive layer may be made of an insulating resin material. The adhesive layer is used to improve the adhesion between the wiring layer 1212 and the substrate 1211, prevent the wiring layer 1212 from falling off, and perform an insulating function when the substrate 1211 is made of a metal material such as aluminum.

In particular, the wiring layer 1212 is located on a side of the substrate 1211 facing the light emitting device 122. The circuit layer 1212 is etched to form a plurality of pad pairs, one pad pair corresponding to each light emitting device 122, one pad pair including a first pad a and a second pad B, and a break K1 is formed between the first pad a and the second pad B by etching, so that a set distance is formed between the first pad a and the second pad B to prevent a short circuit between the first pad a and the second pad B.

The solder mask layer 1213 is located on a side of the wiring layer 1212 facing away from the substrate 1211. The solder mask layer 1213 is coated on the surface of the substrate 1211 and the circuit layer 1212 through screen printing, spin coating, deposition and other processes in the specific implementation, and is used for protecting the circuit of the circuit layer 1212 and avoiding damage to the circuit layer 1212 during soldering.

As shown in fig. 4, the solder resist layer 1213 includes a plurality of windows K2 formed through processes of exposure, development, etching, and the like, the windows K2 being used to expose the first pad a and the second pad B of one pad pair. The Mini LED of the flip-chip structure includes a first electrode 1221 and a second electrode 1222 on a side facing away from the light emitting surface, where the first electrode 1221 is a P electrode, the second electrode 1222 is an N electrode, or the first electrode 1221 is an N electrode, and the second electrode 1222 is a P electrode, which is not limited herein. In connection, the first electrode 1221 and the second electrode 1222 of the Mini LED of the flip-chip structure are placed above the pair of pads exposed by the window K2 facing the wiring layer 1212, so that the first pad a of one pair of pads corresponds to the first electrode 1221 of one Mini LED, the second pad B of the pair of pads corresponds to the second electrode 1222 of the Mini LED, then the first electrode 1221 of the Mini LED of the flip-chip structure is connected to the corresponding first pad a by reflow soldering or the like, and the second electrode 1222 is connected to the corresponding second pad B.

Mini LEDs are different from common light emitting diodes, and specifically refer to Mini LED chips. Because the Mini LED has small size, the dynamic light emission of the backlight module is controlled to be smaller in area, and the contrast ratio of pictures is improved. In the embodiment of the invention, the Mini LED can be in various sizes, for example, the size of the Mini LED is smaller than 200 mu m, the size of the Mini LED is smaller than 300 mu m or the size of the Mini LED is smaller than 500 mu m.

Fig. 5 is a schematic cross-sectional structure of a Mini LED lamp panel in the related art.

Due to the smaller size of the Mini LEDs, the size of the window formed on the solder mask 1213 for soldering the Mini LEDs is correspondingly smaller than that of a general light emitting diode. In order to simplify the windowing step and reduce the difficulty of windowing, as shown in fig. 5, when a lamp panel manufactured by using a Mini LED with a flip-chip structure is used for windowing a solder mask, the window is not independently performed on a first pad a and a second pad B in each pad pair, but the window K2 is directly used for simultaneously exposing a first pad a, a second pad B and a fracture K1 between the first pad a and the second pad B in one pad pair, and under the condition that no reflective part is arranged, most of light rays incident into the fracture K1 are absorbed by the circuit board and cannot be utilized due to lower reflectivity of the circuit board material.

In the embodiment of the present invention, as shown in fig. 4, after the solder mask 1213 is windowed, the first bonding pad a, the second bonding pad B and the fracture K1 between the first bonding pad a and the second bonding pad B are exposed, one fracture K1 forms a groove H, and the reflective material is filled in the groove H to form the reflective portion 123, so that the light incident into the groove H can exit to the light-emitting side of the lamp panel again after being reflected by the reflective portion 123, thereby greatly improving the light-emitting efficiency of the lamp panel.

Fig. 6 is a third schematic cross-sectional view of a lamp panel according to an embodiment of the invention.

In some embodiments, as shown in fig. 6, a surface of the substrate 1211 facing a side of the wiring layer 1212 may include a plurality of recesses K3, the recesses K3 being located between the first and second pads a and B. In particular, as shown in fig. 6, one concave portion K3 corresponds to a fracture K1 formed between a first pad and a second pad in a pair of pads, and it is required to ensure that the concave portion K3 at least partially coincides with an orthographic projection of the corresponding fracture K1 on the substrate 1211 during the particular manufacturing, so that the concave portion K3 and the corresponding fracture K1 together form a groove H.

Since the thickness of the wiring layer 1212 formed by copper plating is generally 18 to 36 μm, the depth of the fracture K1 is generally 18 to 36 μm, and the depth of the groove H formed only by the fracture K1 is small, and since the reflectance of the light reflecting portion 123 is proportional to the thickness of the light reflecting portion 123, the depth of the groove H can be increased by further forming the recess K3 on the substrate 1211, and thus the thickness of the light reflecting portion 123 can be increased, and the light extraction efficiency of the lamp panel can be further improved.

In practice, the material of the light reflecting portion 123 may be a light reflecting material, such as white ink having a reflective property for light, so that the light incident to the groove H may be reflected again to the light emitting side by the light reflecting portion 123, thereby improving the utilization rate of the light source.

In some embodiments, the material of the solder mask 1213 may also be white ink, so that the solder mask 1213 may reflect light incident on the surface of the lamp panel. When the material of the solder mask 1213 is white ink, the structure of the backlight module may not be provided with the reflective sheet 13 to reflect light, which is not limited herein.

Fig. 7 is a schematic top view of a lamp panel according to an embodiment of the invention.

In some embodiments, as shown in fig. 7, a reflective sheet 13 is disposed at the light emitting side of the lamp panel, and the reflective sheet 13 includes a plurality of openings K4 for exposing the light emitting devices 122. The opening K4 of the reflection sheet 13 is large in size in consideration of assembly errors and swelling and shrinkage of the reflection sheet 13. For example, if the maximum size of the light source and associated components is 1mm, the reflector sheet typically requires an opening of 3-4mm. The opening K4 of the reflective sheet 13 is large to simultaneously expose the corresponding light emitting device 122 and a partial region of the solder resist layer 1213 adjacent to the light emitting device 122. If the solder resist layer 1213 is made of a material having no reflective property, the portion of the region exposed by the opening K4 of the reflective sheet 13 may cause the reflected light to be darker due to the lower reflectivity. Therefore, in practice, the reflective sheet 13 may be provided to reflect light, and the solder resist layer 1213 is simultaneously made of a white ink material to further improve reflection efficiency.

In some embodiments, as shown in fig. 7, the opening K4 of the reflective sheet 13 is circular in shape, the window K2 of the solder resist layer 1213 is rectangular in shape, and the break K1 is rectangular in shape. In particular, the shape of the opening K4 of the reflecting sheet 13, the shape of the window K2 of the solder mask 1213, and the shape of the break K1 may be other shapes, and may be set according to actual conditions, and are not limited herein.

As shown in fig. 7, in the embodiment, the size of the window K2 needs to be larger than that of the light emitting device 122 in consideration of assembly errors, so that the light emitting device 122 can be easily mounted. In the y direction, the length of the exposed bonding pad of the window K2 is greater than the length of the light emitting device 122, so that the length of the fracture K1 is greater than the length of the light emitting device 122, and after the reflective layer 123 is filled in the fracture K1, the orthographic projection of the light emitting device 122 on the circuit board in the y direction can be ensured to fall within the range of the reflective layer 123, and the reflection efficiency is improved.

In the embodiment of the present invention, before the light emitting device 122 is connected to the circuit board 121 by reflow soldering, the solder paste S needs to be printed on the first pad a and the second pad B of the circuit board 121, and the light emitting device 122 and the circuit board 121 are fixed by the solder paste S. As shown in fig. 4, the thickness of the printed solder paste is generally about 30 μm, and since the electrode of the light emitting device 122 is very thin, if the thickness of the solder mask 1213 is too thick, for example, when the thickness of the solder mask is greater than 50 μm, it may result in melting and thinning of the solder paste and misalignment of the pad due to heating during reflow soldering, which causes the light emitting device 122 to overlap the solder mask 1213 on both sides, the position of the light emitting device 122 cannot be pulled positive to form effective soldering, resulting in poor soldering.

In view of this, in the embodiment of the present invention, when the solder mask 1213 is made of white ink, the thickness thereof can be controlled to be 20-30 μm, so that the solder mask can ensure high reflection efficiency and avoid poor soldering caused by excessive thickness.

Similarly, when the thickness of the light reflecting portion 123 is so large that the surface of the light reflecting portion 123 facing the light emitting device tube 122 is higher than the surface of the bonding pad facing the light emitting device 122, solder paste printing is difficult, and when the reflow process is performed, there is also a problem that after the solder paste is melted and thinned due to the too high height of the light reflecting portion 123, the light emitting device 122 is overlapped on the surface of the light reflecting portion 123, and thus effective soldering cannot be performed. Therefore, in actual manufacturing, it is necessary to ensure that the surface of the light reflecting portion 123 facing the light emitting device 122 is not higher than the surface of the pad facing the light emitting device 122 as much as possible, so as to improve the yield of soldering.

In the embodiment of the invention, the reflective portion 123 is disposed in the groove H, and the thickness of the groove H can be adjusted according to the depth of the concave portion K3, and the light incident under the light emitting device 122 is not easy to exit due to the shielding of the light emitting device 122, so that the thickness of the reflective portion 123 can be increased by increasing the depth of the concave portion K3, thereby increasing the reflectivity of the reflective portion 123 and further increasing the light utilization rate. In particular implementation, the thickness of the light reflecting portion 123 may be set to be greater than the thickness of the solder resist layer 1213.

Fig. 8 is a schematic cross-sectional view of a lamp panel according to an embodiment of the invention.

In the above embodiment of the present invention, the structure of the lamp panel is described with the Mini LED in the flip-chip structure. In practical application, the Mini LED can also be of a forward-mounted structure.

As shown in fig. 8, when the light panel is manufactured by using the Mini LED with the front-mounted structure, the first electrode 1221 and the second electrode 1222 of the Mini LED are located on the light emitting surface side of the Mini LED, that is, on the side of the Mini LED facing away from the circuit board 121. In particular implementation, the Mini LED is disposed in a gap between a first pad a and a second pad B of the wiring layer 1212, and a first electrode 1221 and a second electrode 1222 of the Mini LED are connected to the pads by way of metal leads M, respectively. At this time, the groove H may be directly formed on the surface of the substrate 1211 under the Mini LED and the white ink may be filled to form the reflective portion 123, so that the front projection of the Mini LED on the circuit board 121 completely falls within the front projection of the reflective portion 123 on the circuit board 121, and is used for reflecting the light emitted to the side of the substrate 1211. And are not limited herein.

When the light panel is manufactured by using the Mini LED with the front-mounted structure, since the Mini LED can be directly mounted on the substrate and the thickness of the bonding pad is thinner, the circuit board under the Mini LED needs to be perforated to form the groove H for accommodating the light reflecting portion to obtain the thicker light reflecting portion 123. In the specific implementation, the groove H may be manufactured according to actual situations. For example, in general, the brightness of the peripheral edge area of the lamp panel is smaller than that of the central area, so that the grooves H and the light reflecting portions 123 may be disposed only in the peripheral edge area of the lamp panel, thereby improving the brightness of the outgoing light in the peripheral edge area and improving the uniformity of the backlight. For the Mini LED with the flip-chip structure, since the Mini LED is disposed above the break K1 between the first pad a and the second pad B, and the groove H is formed by the break K1, all the Mini LEDs are disposed above the groove, at this time, only part of the groove may be filled with the reflective material according to actual requirements to form the reflective portion 123, for example, only the reflective portion 123 is formed in the groove of the peripheral edge region of the lamp panel, thereby improving the brightness of the outgoing light in the edge region and improving the uniformity of backlight. And are not limited herein.

In a second aspect of the embodiments of the present invention, a method for manufacturing a display device is provided.

Fig. 9 is a flowchart illustrating a method for manufacturing a display device according to an embodiment of the present invention; FIG. 10 is a schematic diagram of a manufacturing process of a display device according to an embodiment of the present invention; FIG. 11 is a second schematic diagram illustrating a manufacturing process of the display device according to the embodiment of the invention; fig. 12 is a third schematic view illustrating a manufacturing process of the display device according to the embodiment of the invention.

In the embodiment of the invention, as shown in fig. 9, the manufacturing method of the display device includes the following steps:

S100: manufacturing a circuit board, and forming a plurality of grooves on the circuit board;

S200: filling a reflective material in the groove to form a reflective part;

s300: and transferring the plurality of light emitting devices to the circuit board, and enabling at least part of the light emitting devices to be positioned above the grooves so that the light reflecting parts are positioned between the light emitting devices and the circuit board to form the lamp panel.

In an embodiment of the invention, a manufacturing process of the display device includes manufacturing a lamp panel for providing a backlight source.

In manufacturing the lamp panel, as shown in fig. 10, a circuit board 121 is first manufactured, and a plurality of grooves are formed on the surface of the circuit board 121 by processes of exposure, development, etching, laser drilling, and the like. The circuit board 121 is for supporting and carrying the light emitting device and providing driving signals to the light emitting device, and includes a plurality of traces of wires and a plurality of pads for connecting the light emitting device.

As shown in fig. 11, the reflective portion 123 is then formed by filling a reflective material in the groove H through printing, coating, deposition, or the like. The light reflecting portion 123 is for reflecting light. The reflective material is a material with reflective properties, and white ink can be specifically selected.

As shown in fig. 12, finally, a plurality of light emitting devices 122 are transferred onto a circuit board 121, and electrodes of the light emitting devices 122 are connected with pads on the circuit board 121 to form a lamp panel. In particular, in the transferring process, at least part of the light emitting device 122 is located above the groove H, so that the light reflecting portion 123 is located between the light emitting device 122 and the circuit board 121, so that after the light L4 emitted from the light emitting device 122 and disposed above the groove H is incident below the light emitting device 122, the light is reflected by the light reflecting portion 123 and then projected in the light emitting direction again, thereby greatly improving the light emitting efficiency of the lamp panel.

In some embodiments, all the light emitting devices 122 may be disposed on the light reflecting portion 123 to improve the overall light emitting efficiency of the lamp panel. Because the brightness of the peripheral edge area of the lamp panel is smaller than that of the central area in general, the grooves and the light reflecting parts can be arranged only in the peripheral edge area of the lamp panel, so that the emergent brightness of the edge area is improved, the backlight uniformity is improved, and the method is not limited.

In the specific implementation, the reflective part may be directly manufactured on the circuit board without providing a groove, which is not limited herein.

FIG. 13 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the invention; FIG. 14 is a schematic diagram of a manufacturing process of a display device according to an embodiment of the present invention; FIG. 15 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the present invention; FIG. 16 is a schematic diagram of a manufacturing process of a display device according to an embodiment of the invention; FIG. 17 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the invention; fig. 18 is a schematic diagram illustrating a manufacturing process of a display device according to an embodiment of the invention.

In particular, the light emitting device 122 may employ Mini LEDs. The Mini LED can be a flip-chip type Mini LED, a front-mounted Mini LED or a vertical Mini LED. Taking the Mini LED of the flip-chip structure as an example, in manufacturing a circuit board, as shown in fig. 13, a layer of conductive material is first deposited on the surface of a substrate 1211 by electroplating, deposition, etc. to form a circuit layer 1212, and then the conductive material is patterned by exposing, developing, etching, etc. to form a pattern of the circuit. In the manufacturing process, a plurality of pad pairs are formed on the circuit layer 1212, wherein one pad pair comprises a first pad a and a second pad B, which are respectively used for connecting two electrodes of the Mini LED. A gap exists between the first pad a and the second pad B in one pair of pads to form a break K1, so that insulation between the first pad a and the second pad B avoids shorting to the Mini LED.

As shown in fig. 14, a solder resist layer 1213 is then formed on the surfaces of the substrate 1211 and the wiring layer 1212. The solder resist layer 1213 serves to protect the wiring of the wiring layer 1212 and to prevent damage to the wiring layer 1212 during soldering.

As shown in fig. 15, a plurality of windows K2 are finally formed on the solder resist layer 1213 by exposure, development, etching, and the like. A window K2 is used to expose a pad pair and the break K1, and a groove H is formed at the break K1.

Or in manufacturing a circuit board, as shown in fig. 16, a layer of conductive material is first deposited on the surface of the substrate 1211 by electroplating, deposition, or the like to form a circuit layer 1212, and then the conductive material is subjected to patterning treatment by exposing, developing, etching, or the like to form a pattern of the circuit. In the manufacturing process, a plurality of pad pairs are formed on the circuit layer 1212, wherein one pad pair comprises a first pad a and a second pad B, which are respectively used for connecting two electrodes of the Mini LED. A gap exists between the first pad a and the second pad B in one pair of pads to form a break K1, so that insulation between the first pad a and the second pad B avoids shorting to the Mini LED.

As shown in fig. 16, a plurality of concave portions K3 are then formed on the substrate 1211 by etching, laser drilling, or the like, the concave portions K3 being located between the first pad a and the second pad B. One of the concave portions K3 corresponds to one of the interruptions K1, and since the substrate 1211 and the circuit layer 1212 are made of different materials, and the steps of forming the concave portions K3 and the interruptions K1 are performed separately, the apertures of the concave portions K3 and the interruptions K1 may be different, and it is necessary to ensure that the orthographic projections of the concave portions K3 and the corresponding interruptions K1 on the substrate 1211 overlap at least partially during the specific manufacturing.

As shown in fig. 17, a solder resist layer 1213 is then formed on the surfaces of the substrate 1211 and the wiring layer 1212. The solder resist layer 1213 serves to protect the wiring of the wiring layer 1212 and to prevent damage to the wiring layer 1212 during soldering.

As shown in fig. 18, a plurality of windows K2 are finally formed on the solder resist layer 1213 by exposure, development, etching, and the like. A window K2 is used to expose a pad pair, the fracture K1 and the recess K3, and a groove H is formed at the fracture K1 and the recess K3.

Or in manufacturing a circuit board, as shown in fig. 13, a layer of conductive material is first deposited on the surface of the substrate 1211 by electroplating, deposition, or the like to form a circuit layer 1212, and then the conductive material is subjected to patterning treatment by exposing, developing, etching, or the like to form a pattern of the circuit. In the manufacturing process, a plurality of pad pairs are formed on the circuit layer 1212, wherein one pad pair comprises a first pad a and a second pad B, which are respectively used for connecting two electrodes of the Mini LED. A gap exists between the first pad a and the second pad B in one pair of pads to form a break K1, so that insulation between the first pad a and the second pad B avoids shorting to the Mini LED.

As shown in fig. 15, a plurality of windows K2 are then formed on the solder resist layer 1213 by exposure, development, etching, or the like. A window K2 is used to expose a pad pair and a break K1.

As shown in fig. 18, a plurality of concave portions K3 are finally formed on the substrate 1211 by etching, laser drilling, or the like, the concave portions K3 being located between the first pad a and the second pad B. One of the concave portions K3 corresponds to one of the interruptions K1, and since the substrate 1211 and the circuit layer 1212 are made of different materials, and the steps of forming the concave portions K3 and the interruptions K1 are performed separately, the apertures of the concave portions K3 and the interruptions K1 may be different, and it is necessary to ensure that the orthographic projections of the concave portions K3 and the corresponding interruptions K1 on the substrate 1211 overlap at least partially during the specific manufacturing. The window K2 of the final solder mask 1213 exposes the pair of pads, the break K1 and the corresponding recess K3 thereof, and forms a groove H at the break K1 and the corresponding recess K3 thereof.

In some embodiments, the material of the solder mask 1213 may be white ink, so that the solder mask 1213 also has a function of reflecting light. When the material of the solder mask 1213 is white ink, in the process of manufacturing the circuit board, when the window K2 is manufactured on the solder mask 1213, the etching or punching time can be controlled, so that the window K2 just exposes the surface of the pad pair, while the white ink with a certain thickness is still reserved in the groove H, and the white ink reserved in the groove H is used as the material of the light reflecting portion 123 to reflect light, so that the subsequent step of filling the reflective material into the groove H can be reduced, and the material cost and the time cost can be saved.

In the embodiment of the invention, when the Mini LED adopts the Mini LED with the flip-chip structure, transferring the plurality of Mini LEDs to the circuit board specifically comprises connecting a first electrode of the Mini LED with a first bonding pad A and connecting a second electrode of the Mini LED with a second bonding pad B. The first electrode and the second electrode are positioned on one side of the light emitting surface facing away from the Mini LED.

In the embodiment of the invention, after the lamp panel is manufactured, the lamp panel can be fixed on the back plate, then optical elements such as the reflecting sheet, the diffusion plate, the optical film and the like are sequentially arranged on the light emitting side of the lamp panel to form the backlight module, and then the display panel is arranged on the light emitting side of the backlight module to finish the manufacturing of the display device.

According to a first inventive concept, a display device includes: a display panel for displaying an image; the backlight module is positioned on the light incident side of the display panel and is used for providing backlight; the backlight module comprises a lamp panel; the lamp plate includes: a circuit board for providing a driving signal; the light emitting devices are positioned on the circuit board and are electrically connected with the circuit board; the light reflecting parts correspond to at least part of the light emitting devices, one light reflecting part corresponds to one light emitting device, and the light reflecting parts are positioned between the corresponding light emitting devices and the circuit board. The light reflecting part is arranged between at least part of the light emitting devices and the circuit board, so that the light emitted from the bottom of the light emitting devices is incident to one side of the circuit board and then projected in the light emitting direction again after being reflected by the light reflecting part, and the light emitting efficiency of the lamp panel is greatly improved.

According to a second inventive concept, the number of light reflecting portions is equal to the number of light emitting devices; the front projection of the light reflecting part on the circuit board and the front projection of the light emitting device on the circuit board have an overlapping area.

According to a third inventive concept, the surface of the circuit board facing the side of the light emitting device has a plurality of grooves; one groove corresponds to one light reflecting part, and the light reflecting part is positioned in the corresponding groove.

According to a fourth inventive concept, a light emitting device includes a first electrode and a second electrode; the circuit board comprises: a substrate; the circuit layer is positioned on one side of the substrate facing the light-emitting device; the circuit layer comprises a plurality of pad pairs; a pad pair including a first pad and a second pad; one bonding pad pair corresponds to one light emitting device, a first bonding pad in the bonding pad pair is connected with a first electrode of the light emitting device, and a second bonding pad in the bonding pad pair is connected with a second electrode of the light emitting device; the solder mask layer is positioned on one side of the circuit layer, which is away from the substrate; the solder mask layer comprises a plurality of windows; a window for exposing a pad pair; the first bonding pad and the second bonding pad in the bonding pad pair exposed through windowing are separated by a set distance, and the light reflecting part is located between the first bonding pad and the second bonding pad.

According to a fifth inventive concept, a surface of a side of the substrate facing the wiring layer includes a plurality of concave portions between the first pad and the second pad; the concave part is used for forming a groove, so that the thickness of the reflecting part can be increased, and the reflecting efficiency is improved.

According to the sixth inventive concept, the surface of the light reflecting portion facing the light emitting device is not higher than the surface of the bonding pad facing the light emitting device, so that poor welding caused by excessive high light reflecting portion is avoided.

According to the seventh inventive concept, the reflective part and the solder mask are both made of white ink, and the solder mask can reflect light rays to further improve the radiation efficiency.

According to the eighth inventive concept, the thickness of the solder mask layer is 20-30 μm, so that poor welding is avoided; the thickness of the light reflecting part is larger than that of the solder mask layer, so that the light reflecting part has enough thickness to reflect more light.

According to a ninth inventive concept, the backlight module further comprises: the reflecting sheet is positioned on one side of the circuit board close to the light emitting device; the reflector sheet comprises a plurality of openings; the opening is used for exposing a part of the solder mask adjacent to the light emitting device.

According to a tenth inventive concept, the light emitting device is a Mini LED chip, the size of which is less than 500 μm.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A display device, comprising:

A display panel for displaying an image;

The backlight module is positioned on the light incident side of the display panel and is used for providing backlight; the backlight module comprises a lamp panel; the lamp panel includes:

A circuit board for providing a driving signal;

2. The display apparatus according to claim 1, wherein the number of the light reflecting portions is equal to the number of the light emitting devices;

And an overlapping area exists between the orthographic projection of the light reflecting part on the circuit board and the orthographic projection of the light emitting device on the circuit board.

3. The display apparatus according to claim 1, wherein a surface of the circuit board facing the light emitting device side has a plurality of grooves; one groove corresponds to one light reflecting part, and the light reflecting part is positioned in the corresponding groove.

4. A display device according to claim 3, wherein the light-emitting device comprises a first electrode and a second electrode;

The circuit board includes:

A substrate;

The circuit layer is positioned on one side of the substrate facing the light-emitting device; the circuit layer comprises a plurality of bonding pad pairs; one of the pad pairs includes a first pad and a second pad; one of the bonding pad pairs corresponds to one of the light emitting devices, the first bonding pad of the bonding pad pair is connected with a first electrode of the light emitting device, and the second bonding pad of the bonding pad pair is connected with a second electrode of the light emitting device;

the solder mask layer is positioned on one side of the circuit layer, which is away from the substrate; the solder mask layer comprises a plurality of fenestrations; one of the windows is used for exposing one of the pad pairs;

And the light reflecting part is positioned between the first bonding pad and the second bonding pad.

5. The display device according to claim 4, wherein a surface of the substrate facing the side of the wiring layer includes a plurality of concave portions, the concave portions being located between the first pad and the second pad; the concave part is used for forming the groove.

6. The display apparatus according to claim 4 or 5, wherein a surface of the light reflecting portion facing the light emitting device side is not higher than a surface of the pad pair facing the light emitting device side.

7. The display device according to claim 6, wherein the material of the light reflecting portion and the solder resist layer is white ink.

8. The display device according to claim 7, wherein the thickness of the solder resist layer is 20 to 30 μm; the thickness of the light reflecting part is larger than that of the solder mask layer.

9. The display device of claim 7, wherein the backlight module further comprises:

the reflecting sheet is positioned on one side of the circuit board close to the light emitting device; the reflector sheet includes a plurality of openings; the opening is used for exposing a part of the solder mask layer adjacent to the light emitting device.

10. The display apparatus of any one of claims 1 to 5, wherein the light emitting device is a Mini LED chip, and the size of the Mini LED chip is less than 500 μm.