CN111818204B

CN111818204B - Preparation method of back cover assembly

Info

Publication number: CN111818204B
Application number: CN202010662380.0A
Authority: CN
Inventors: 林柏青
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2022-04-15
Anticipated expiration: 2040-07-10
Also published as: TW202203730A; CN111818204A; TWI742768B

Abstract

Embodiments of the present invention provide a back cover assembly, which includes a back cover and a functional layer. The back cover includes a bottom and a side portion bent and extended from the bottom. The functional layer is located on the side portion and partially extends to the bottom portion. Wherein, the side part defines a sensing key area and a display area, the functional layer includes a sensing key layer and a micro LED display layer, the sensing key area is provided with the sensing key layer, and the display area is provided with a The micro-LED display layer. Embodiments of the present invention also provide a preparation method of the back cover assembly and an electronic device using the same.

Description

Preparation method of back cover assembly

Technical Field

The invention relates to the technical field of display, in particular to a back cover assembly, a preparation method thereof and an electronic device.

Background

Currently, in order to achieve the function of side display, most electronic devices (e.g., mobile phones) employ a front display screen extending to the side, and the corners of the display screen still need to be covered by a back cover located below the display screen. In addition, the existing mobile phone needs to be provided with a hole on the back cover to keep the solid key. This limits the choice of materials for the back cover and reduces its impact strength. Therefore, how to combine the impact strength of the back cover (without opening the hole) while maintaining the side display function of the mobile phone becomes a consideration in future design.

Disclosure of Invention

An embodiment of the present invention provides a back cover assembly, which includes:

the back cover comprises a bottom and side edge parts bent and extended from the bottom; and

the functional layer is positioned on the side edge part and partially extends to the bottom part;

the functional layer comprises an induction key layer and a micro LED display layer, the induction key layer is arranged in the induction key area, and the micro LED display layer is arranged in the display area.

The back cover assembly is provided with a micro LED display layer at least at the side edge part of the back cover, so that the side edge of the back cover assembly can have a display function. In addition, this back of body lid subassembly still is provided with the response button layer at the side portion at least to replace the button of entity, so, need not to cover the trompil on the back of body, strengthened the shock resistance intensity of back of body lid. Therefore, the back cover assembly has better strength and side display function under the condition that the back cover is not provided with the hole.

Another embodiment of the present invention further provides a method for manufacturing a back cover assembly, including:

providing a back cover, wherein the back cover comprises a bottom and side edge parts bent and extended from the bottom; and

providing a functional layer, wherein the functional layer is positioned on the side edge part and partially extends to the bottom part;

According to the preparation method of the back cover assembly, on one hand, the miniature LED display layer is formed at least on the side edge part of the back cover, so that the side edge of the back cover assembly can have a display function. In addition, in the method, at least the side edge part is also provided with an induction key layer to replace the entity key. Therefore, the method does not need to form holes on the back cover, and the impact resistance of the back cover is enhanced. Therefore, the back cover assembly has better strength and side display function under the condition that the back cover is not provided with the hole.

Another embodiment of the present invention further provides an electronic device, which includes a protective cover plate, a display module, and a back cover module, which are sequentially stacked, wherein the back cover module is the above back cover module, the back cover defines an accommodating space, and the display module is located in the accommodating space.

The back cover assembly has better strength under the condition that the back cover is not provided with the hole, and simultaneously has a side display function, so that an electronic device applying the back cover assembly also has the side display function. In addition, the back cover has better impact strength without opening holes, so that the display assembly contained in the back cover can be well protected.

Drawings

Fig. 1 is an exploded view of a back cover assembly according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of the back cover in fig. 1.

Fig. 3 is a schematic cross-sectional view of the display layer of the micro LED in fig. 1.

FIG. 4 is a cross-sectional view of a sensor device.

Fig. 5 is a schematic cross-sectional view of the sensor element when pressed.

Fig. 6 is an exploded view of a back cover assembly in accordance with another embodiment of the present invention.

Fig. 7 is a flowchart of a method for manufacturing a back cover assembly according to an embodiment of the invention.

Fig. 8A is a schematic view illustrating a flexible substrate provided in a method for manufacturing a back cover assembly according to an embodiment of the invention.

Fig. 8B is a schematic view illustrating forming traces in a manufacturing method of a back cover assembly according to an embodiment of the invention.

Fig. 8C is a schematic diagram illustrating the formation of the bonding pads in the method for manufacturing the back cover assembly according to the embodiment of the invention.

Fig. 8D is a schematic diagram illustrating a transferring step in a manufacturing method of a back cover assembly according to an embodiment of the invention.

Fig. 8E is a schematic diagram of a packaging step in a manufacturing method of the back cover assembly according to an embodiment of the invention.

Fig. 8F is a schematic diagram of a peeling step in a manufacturing method of a back cover assembly according to an embodiment of the invention.

Fig. 8G is a schematic diagram of a conformalization step in a method of making a back cover assembly according to an embodiment of the invention.

Fig. 8H is a schematic view illustrating a micro LED display layer being fixed in a manufacturing method of the back cover assembly according to an embodiment of the invention.

Fig. 8I is a schematic diagram of a conformal step in a method of making a back cover assembly according to an embodiment of the invention.

Fig. 8J is a schematic diagram of a conformable step in a method of making a back cover assembly in accordance with an embodiment of the present invention.

Fig. 8K is a schematic diagram of a binding step in a manufacturing method of a back cover assembly according to an embodiment of the invention.

Fig. 9 is an exploded view of a back cover assembly in accordance with yet another embodiment of the present invention.

Fig. 10 is a flow chart of a method for manufacturing a back cover assembly according to yet another embodiment of the present invention.

Fig. 11 is an exploded view of an electronic device according to an embodiment of the invention.

Description of the main elements

Back cover assembly

10, 20, 30

Back cover 12

Display area 123

Induction key area 125

Accommodating space 121

Bottom 122

Side edge part 124

Functional layer 13

Micro LED display layer 14

Base material 142

Drive element 144

Micro LED146

Decorative layer 16

Sensing key layer 18

Sensing element 182

First protective layer 1821

First electrode layer 1822

Piezoelectric material layer 1823

Second electrode layer 1824

Second protective layer 1825

Upper die 40

Bump 42

Air blowing hole 44

Lower die 50

Upper jig 60

First lower fixture 70

Second lower jig 72

Substrate 141

Wiring 143

Binding pad 145

Encapsulation layer 147

Electronic device 100

Protective cover plate 80

Display assembly 90

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

Fig. 1 is an exploded view of a back cover assembly 10 in accordance with one embodiment of the present invention. The back cover assembly 10 can be used in electronic devices such as mobile phones and tablet computers. As shown in fig. 1, the back cover assembly 10 includes a back cover 12, a micro LED display layer 14, and an induction button layer 18 in sequence from outside to inside. The back cover 12 includes a bottom portion 122 and a side portion 124 extending from the bottom portion 122. The micro LED display layer 14 and the sensing key layer 18 constitute the functional layer 13. The functional layer 13 is disposed on the side edge portion 124 and partially extends to the bottom portion 122. In the back cover assembly 10, the micro LED display layer 14 is located between the sensing button layer 18 and the back cover 12.

The back cover assembly 10 is provided with a micro LED display layer 14 at least at the side edge portion 124 of the back cover 12, so that the side edge of the back cover assembly 10 can have a display function. In addition, the back cover assembly 10 has the sensing key layer 18 hidden on the side of the micro LED display layer 14 away from the back cover 12 to replace the solid keys, so that no holes need to be formed in the back cover 12, the impact resistance of the back cover 12 is enhanced, the back cover assembly 10 can maintain the strength of the back cover 12 without forming holes in the back cover 12, and meanwhile, the back cover assembly has the function of side display.

In one embodiment, the back cover 12 and the micro LED display layer 14, and the micro LED display layer 14 and the sensing key layer 18 are fixed by adhesion layers (not shown). The adhesive layer can be a single-layer adhesive layer, a laminated layer matched with different adhesive layers or a laminated layer consisting of a substrate layer and adhesive layers respectively positioned on two opposite surfaces of the substrate layer.

Fig. 2 is a schematic structural diagram of the back cover 12 in fig. 1. As shown in fig. 2, the back cover 12 is a seamless back cover 12, and the bottom 122 and the side 124 are integrated.

The side portion 124 defines an induction button area 125 and a display area 123. The sensing button area 125 and the display area 123 are both provided with the micro LED display layer 14, and the sensing button area 125 and the display area 123 are both provided with the sensing button layer 18. The micro LED display layer 14 in the display area 123 can perform a side image display, and the micro LED display layer 14 in the induction key area 125 is a dummy micro LED display layer and is not used for an image display. Similarly, the sensing key layer 18 in the display area 123 is also a dummy (dummy) sensing key layer, and is not used for key operation, and only the sensing key layer 18 in the sensing key area 125 is used for key operation.

In fig. 2, the induction button area 125 is adjacent to the display area 123. In other embodiments, the back cover 12 can be provided with two sensing button regions 125 respectively located at two sides of the display region 123, but not limited thereto.

In one embodiment, the bottom portion 122 of the back cover 12 is substantially rectangular, and the side portions 124 are formed by bending the edges of the bottom portion 122 in the same direction. The bottom portion 122 and the side portion 124 enclose a receiving space 121 to receive the display module 90 of the electronic device 100. The display assembly 90 is used as an element for displaying a front view of the electronic device 100, and may be an LCD display assembly, an OLED display assembly, a Micro LED display assembly, or the like.

In one embodiment, the back cover 12 may be other shaped back covers, for example, the back cover 12 may have an inner surface and an outer surface both curved.

In one embodiment, the micro LED display layer 14 and the sensing button layer 18 are disposed corresponding to the side edge portion 124, and partially extend to cover the bottom portion 122 of the back cover 12 for binding with other components (e.g., a circuit board) at the bottom portion 122. The micro LED display layer 14 and the sensing button layer 18 may be disposed only corresponding to the side portion 124 of the back cover 12 on one side of the bottom portion 122, or may be disposed corresponding to the side portions 124 on two opposite sides of the bottom portion 122, without limitation.

In one embodiment, the back cover 12 is made of glass or plastic. Wherein the glass may be strengthened glass to enhance the impact strength of the back cover 12. The plastic may be a composite of multiple plastic layers. The back cover 12 may be clear or tinted. In the embodiment shown in fig. 1, back cover 12 is tinted glass.

Fig. 3 is a schematic cross-sectional view of the micro LED display layer 14 in fig. 1. As shown in fig. 3, the micro LED display layer 14 includes a flexible substrate 142, a driving element 144 disposed on the substrate 142, and a micro LED146 electrically connected to the driving element 144. The micro LED display layer 14 is flexible and bendable so that it can be conformed to conform to different shapes of the back cover 12.

In one embodiment, the material of the substrate 142 is, for example, Polyimide (PI), polyethylene terephthalate (PET), Polycarbonate (PC), or the like.

In one embodiment, the driving element 144 is electrically connected to a circuit board of the electronic device 100 to drive the micro LED146 to emit light to realize the side display function. The micro LEDs 146 may include micro LEDs emitting different colors of light, such as red light emitting micro LEDs, blue light emitting micro LEDs, and green light emitting micro LEDs, and the electronic device 100 implements a side display function by mixing three primary colors of red, green, and blue.

In one embodiment, the micro-LEDs 146 range in size from approximately 1 micron to approximately 100 microns.

In an embodiment, the sensing key layer 18 includes, for example, a substrate layer (not shown) and a plurality of sensing elements 182 spaced apart from each other on one surface of the substrate layer, or includes a substrate layer and a plurality of sensing elements 182 spaced apart from each other on two opposite surfaces of the substrate layer. When a user presses the position of the corresponding sensing key layer 18 of the back cover 12, the electronic device 100 can respond to the user's pressing to implement the corresponding key function. The key functions include, for example, switching of a power supply, addition or subtraction of a volume key, and the like.

In one embodiment, as shown in fig. 4, the sensing element 182 includes a first passivation layer 1821, a first electrode layer 1822, a piezoelectric material layer 1823, a second electrode layer 1824, and a second passivation layer 1825 sequentially stacked. The piezoelectric material layer 1823 is made of Polyvinylidene fluoride (PVDF), the first and

second protection layers

1821 and 1825 are made of polyester fiber (polyester), and the first and

second electrode layers

1822 and 1824 are made of metal or other conductive materials.

As shown in fig. 5, when the sensing element 182 is pressed, the piezoelectric material layer 1823 is strained due to the mechanical stress, and the piezoelectric material layer 1823 generates a charge change. The change in charge created by the piezoelectric material layer 1823 enables tactile sensing use of the sensed location and pressure level.

In the back cover assembly 10, the back cover 12 is a seamless back cover, and at least the side portion 124 of the back cover 12 is provided with the micro LED display layer 14 and the sensing key layer 18, so that the back cover 12 has a side display function while maintaining the strength without digging a hole.

Fig. 6 is an exploded view of a back cover assembly 20 according to another embodiment of the present invention, which differs from the back cover assembly 10 of fig. 1 in that: in fig. 6, the back cover 12 is transparent, and the back cover assembly 20 further includes a decorative layer 16 between the sensing button layer 18 and the micro LED display layer 14. The micro LED display layer 14 and the decoration layer 16, and the decoration layer 16 and the induction key layer 18 are fixed by adhesion layers (not shown).

In one embodiment, the decorative layer 16 includes a resin layer (not shown), an ink layer (not shown), and an adhesion promoting layer (not shown) sequentially stacked. The resin layer may be a highly extensible resin layer and the adhesion promoting layer may be a modified adhesion promoting layer.

An embodiment of the present invention further provides a method for manufacturing the back cover assembly 10 (20). As shown in fig. 7, the method includes the following steps.

Step S11: a back cover 12 is provided, the back cover 12 includes a bottom portion 122 and a side portion 124 extending from the bottom portion 122.

Step S12: a micro LED display layer 14 is provided.

In one embodiment, step 12 includes providing a flexible substrate 142, disposing a driving element 144 on the substrate 142, transferring the micro LEDs 146 onto the substrate 142, and electrically connecting the micro LEDs 146 and the driving element 144.

As shown in fig. 8A, since the base 142 is flexible, a rigid substrate 141 can be disposed under the base 142 for supporting. The hard substrate 141 is, for example, glass.

As shown in fig. 8B, the step of disposing the driving element 144 on the substrate 142 may include forming a plurality of traces 143 on the substrate 142, wherein the traces 143 are made of metal, for example.

As shown in fig. 8C, the step of disposing the driving element 144 on the substrate 142 further includes forming a plurality of bonding pads 145. One end of each trace 143 near the edge of the substrate 142 may be disposed with one bonding pad 145, and the other end thereof may be disposed with a plurality of bonding pads 145.

As shown in fig. 8D, a plurality of micro LEDs 146 are transferred onto the substrate 142. Wherein each micro LED146 can be transferred to a corresponding bonding pad 145. The micro LEDs 146 may be arranged in a row of micro LEDs emitting red light, a row of micro LEDs emitting blue light, and a row of micro LEDs emitting green light, which are periodically and repeatedly arranged, but not limited thereto.

As shown in fig. 8E, after the micro LEDs 146 are transferred onto the substrate 142, an encapsulation layer 147 is formed on a side of the micro LEDs 146 away from the substrate 142 to protect the micro LEDs 146 from moisture. Thus, the substrate 142, the traces 143, the bonding pads 145, the micro LEDs 146, and the packaging layer 147 together form a micro LED display layer 14.

As shown in fig. 8F, the base 142 of the micro LED display layer 14 is peeled off from the substrate 141 supporting it for subsequent attachment to the back cover 12.

Step S13: the micro LED display layer 14 is disposed on the back cover 12 using a Conformal (Conformal) process. Wherein at least the display area 123 is formed with a micro LED display layer 14.

As shown in fig. 8G, the micro LED display layer 14 is attached to the inner surface of the side portion 124 of the back cover 12. The micro LED display layer 14 may be disposed on an inner surface of one side of the back cover 12, or disposed on inner surfaces of a plurality of sides of the back cover 12.

Specifically, the conformal process may include: fixing the element to be conformed (i.e., micro LED display layer 14), pressing down on upper mold 40 to fix micro LED display layer 14 in the face of back cover 12, and blow molding. As shown in fig. 8H, the back cover 12 is fixed in the lower mold 50 by the first lower jig 70 and the second lower jig 72, and the edge of the micro LED display layer 14 is fixed between the upper mold 40 and the lower mold 50.

As shown in fig. 8I, the upper mold 40 is pressed downward so that the bumps 42 on the upper mold 40 press the micro LED display layer 14 down to the bottom 122 of the back cover 12.

As shown in fig. 8J, the upper mold 40 is provided with a blow hole 44. Wherein the air blowing holes 44 are located between the bumps 42 and the first lower jig 70. After the micro LED display layer 14 is fixed to the bottom 122 of the back cover 12, air is blown into the air blowing holes 44, so that the micro LED display layer 14 is shaped and attached to the side portions 124 of the back cover 12.

As shown in fig. 8K, after the micro LED display layer 14 is attached to the back cover 12, a bonding process is further included to lead out the bonding pad 145 at one end of the trace 143 for electrically connecting with other components (e.g., a circuit board).

Step S14: an induction key layer 18 is disposed on a side of the micro LED display layer 14 away from the side edge portion 124. Wherein, at least the sensing key region 125 is formed with a sensing key layer 18.

In one embodiment, an adhesive layer may be used to attach the sensing button layer 18 to the surface of the micro LED display layer 14 away from the side edge 124.

In another embodiment, step S1 provides that the back cover 12 is transparent, and step S4 includes attaching a decorative layer 16 to the surface of the micro LED display layer 14 away from the side edge 124 by using an adhesive layer, and then attaching the induction button layer 18 to the surface of the decorative layer 16 away from the micro LED display layer 14 by using an adhesive layer.

In the manufacturing method of the back cover assembly 10(20), the micro LED display layer 14 and the back cover 12 can be attached to each other according to different shapes of the back cover 12 by using a conformal process. In addition, the micro LED146 is selected as the side display element of the micro LED display layer 14, and since the micro LED146 has a very small size and supports the flexible substrate 142, the micro LED display layer 14 is flexible, and the stress of the conformal process can be released.

Fig. 9 is an exploded view of a back cover assembly 30 in accordance with yet another embodiment of the present invention. As shown in fig. 9, it is different from the back cover assembly 20 in fig. 6 in that: in fig. 9, in the back cover assembly 30, the micro LED display layer 14 and the induction key layer 18 included in the functional layer 13 are located in the same film layer, the micro LED display layer 14 is disposed in the display area 123, and the induction key layer 18 is disposed in the induction key area 125. In the back cover assembly 30, the back cover 12 is made of plastic.

In one embodiment, the back cover 12 is transparent, and the back cover assembly 30 further includes a decorative layer 16 disposed between the back cover 12 and the layers of the micro LED display layer 14 and the sensor key layer 18.

Fig. 10 is a flow chart illustrating a method for manufacturing the back cover assembly 30 according to still another embodiment of the present invention. As shown in fig. 10, the method includes the following steps.

Step S21: a back cover 12 is provided. The back cover 12 includes a bottom portion 122 and a side portion 124 extending from the bottom portion 122.

Step S22: a functional layer 13 is formed on the back cover 12.

In step S22, the sensing button layer 18 and the micro LED display layer 14 may be formed on the same film by In-Mold Electronics (IME) technology and then ejected out of the decoration layer 16 formed on the other film.

Specifically, step S22 includes: printing a decoration layer 16 on a first film, forming the induction key layer 18 on one area of a second film, forming the micro LED display layer 14 on the other area of the second film, and performing in-mold injection molding on the first film with the decoration layer 16, the second film with the induction key layer 18 and the micro LED display layer 14, and a plastic material to form the back cover assembly 30. Wherein, at least the induction key area 125 is provided with the induction key layer 18, and at least the display area 123 is provided with the micro-LED display layer 14.

In one embodiment, the material of the back cover 12 is transparent plastic, and the step of printing the decoration layer 16 on the first film may be changed to printing a protection layer (not shown) on the first film.

In one embodiment, the step of forming the sensing key layer 18 on the second film may include printing a circuit layer on the second film, and patterning the circuit layer to form the sensing key layer 18 including a plurality of sensing elements 182.

In an embodiment, the step of forming the micro LED display layer 14 on the second film may include steps of bulk transferring the micro LEDs and packaging, which are specifically referred to as step S12 and will not be described herein again.

In an embodiment, the material of the first film and the second film may be polyethylene terephthalate (PET) or Polycarbonate (PC).

Through IME technology for functional layer 13 and decorative layer 16 or protective layer once encapsulation shaping, reduced assembly process, the structure is simpler, has improved production efficiency.

An embodiment of the invention further provides an electronic device 100. As shown in fig. 11, the electronic device 100 includes a protective cover 80, a display unit 90, and a back cover unit 10(20, 30) stacked in this order. The back cover 12 defines an accommodating space 121, and the display assembly 90 can be accommodated in the accommodating space 121. The display assembly 90 is used as an element for displaying a front view of the electronic device 100, and may be an LCD display assembly, an OLED display assembly, a Micro LED display assembly, or the like.

In one embodiment, the display device 90 may also include a touch structure, so that the electronic device 100 has a touch display function.

In an embodiment, the electronic device 100 may be a mobile phone, a tablet computer, or the like. Since the back cover assembly 10(20, 30) has better strength without opening the hole in the back cover 12 and has the side display function, the electronic device 100 using the same also has the side display function. In addition, since the back cover 12 has a better impact strength without opening holes, the display assembly 90 accommodated therein can be well protected.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present invention.

Claims

1. A method of making a back cover assembly, comprising:

the functional layer comprises an induction key layer and a micro LED display layer, the induction key layer is arranged in the induction key area, and the micro LED display layer is arranged in the display area;

the step of providing the functional layer includes forming the micro LED display layer in the display area using a conformal process;

the conformal process includes:

providing an upper die, a lower die, a first lower jig and a second lower jig, wherein the upper die and the lower die are arranged oppositely, the first lower jig and the second lower jig are sequentially arranged on the lower die, and the upper die is provided with a lug facing the lower die and an air blowing hole positioned between the lug and the first lower jig;

fixing the back cover in the lower die through the first lower jig and the second lower jig;

fixing the edge of the micro LED display layer between the upper die and the lower die;

pressing the upper mold down so that the bumps on the upper mold press the micro LED display layer down to the bottom of the back cover; and

and blowing air to the air blowing holes so that the micro LED display layer is shaped and attached to the side edge part of the back cover.

2. The method of making a back cover assembly of claim 1, wherein the step of providing said functional layer comprises:

forming the induction key layer in the induction key area;

the micro LED display layer is positioned between the induction key layer and the back cover.

3. The method of making a back cover assembly according to claim 2, wherein the back cover is transparent, the method further comprising forming a decorative layer between the sensor button layer and the micro LED display layer.