WO2019014823A1

WO2019014823A1 - Adhesive sealing of bonding layers in display devices

Info

Publication number: WO2019014823A1
Application number: PCT/CN2017/093291
Authority: WO
Inventors: De-han LI
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2017-07-18
Filing date: 2017-07-18
Publication date: 2019-01-24

Abstract

A display device (100), comprising: a protective panel (102); a display panel (104); a bonding layer (106) between the protective panel (102) and the display panel (104); an adhesive sealant (108) formed by applying a liquid sealant around a portion of the bonding layer (106) between the protective panel (102) and the display panel (104), the liquid sealant providing a solid seal in a cured state, thereby providing an enhanced bonding between the protective panel (102) and the display panel (104).

Description

ADHESIVE SEALING OF BONDING LAYERS IN DISPLAY DEVICES

BACKGROUND

Various display devices are used for multimedia devices such as televisions, mobile phones, notebook/tablet computers, navigation devices, game consoles, and the like. Recently, display devices have included touch panels as input devices. A display device having a touch panel is manufactured by bonding such a touch panel to a display panel (e.g., liquid crystal display (LCD)) using an optically clear adhesive (OCA) . For example, the OCA may be sandwiched or placed between the touch panel and a polarizing layer of the display panel to facilitate bonding between the touch panel and the display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples are described in the following detailed description and in reference to the drawings, in which:

FIG. 1A illustrates a cross-sectional view of an example display device depicting an adhesive sealant around a portion of a bonding layer；

FIG. 1B illustrates the cross-sectional view of the example display device of FIG. 1A, depicting additional features；

FIG. 2A illustrates a cross-sectional view of an example display device depicting an adhesive sealant along at least one side of the bonding layer covering an outline dimension of the display panel；

FIG. 2B illustrates the cross-sectional view of the example display device of FIG. 2A, depicting additional features；

FIG. 2C illustrates an exploded perspective view of an example display device, such as shown in FIGs. 2A and 2B； and

FIG. 3 is a flow chart illustrating an example method for forming a seal around a bonding material between a touch panel and a display panel.

DETAILED DESCRIPTION

A display device having a touch panel is manufactured by bonding such a touch panel to a display panel (e.g., LCD) using an OCA. In this case, atouch screen is formed by attaching a polarizing sheet on the surface of display panel, mounting a driving chip or a flexible circuit board on the display panel, attaching the OCA as an adhesive on the polarizing sheet, and then attaching the touch panel on the OCA. In such cases, a gap may be formed between the touch panel and the display panel around the OCA bonding. When users give tactile input to the touch panel, the touch panel may oppose against the display panel, thus a ripple may appear on a portion of the touch screen due to the gap formed there between. For example, when the touch screen is pressed by a finger or shook, the touch screen may prone to generate a phenomenon similar to ripples on the water, at a position applied by an external force. The main reason for this phenomenon is that the liquid crystal molecules in the LCD are applied by the external force, thus the deflection of the liquid crystal molecules may be inconsistent, and hence abnormal display can be caused. Also in such cases, the display panel can be damaged by the external force.

Examples described herein may provide a display device including a protective panel (e.g., touch panel) , a display panel (e.g., LCD) , a bonding layer (e.g., OCA layer) between the protective panel and the display panel, and an adhesive sealant (e.g., room temperature vulcanization silicone sealant) around a portion (e.g., at least one side) of the bonding layer between the protective panel and the display panel. The adhesive sealant may be formed by applying a liquid sealant, which provides a solid seal in a cured state. In one example, the adhesive sealant may be used to seal the portion of the bonding layer along sides of the display device that cause ripple during touch interactions.

Examples described herein may improve ripple performance of the display device during touch interactions. Examples described herein may endure ～500g force for the ripple measurement, while enlarging OCA dimension may provide a gain of～300g force for the ripple measurement. Also, examples described herein can be leveraged to existing project/products such as a notebook, tablet personal computer (PC) , smart phone, television, and the like. Examples described herein may extend lifetime of the display panel such as liquid crystal display (LCD) , light-emitting diode (LED) , and the like. Examples described herein may utilize the liquid sealant which can be able to fill the gap between the protective panel and the display panel, thereby providing an enhanced bonding between the protective panel and the display panel.

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present techniques. It will be apparent, however, to one skilled in the art that the present apparatus, devices and systems may be practiced without these specific details. Reference in the specification to “an example” or similar language means that a particular feature, structure, or characteristic described is included in at least that one example, but not necessarily in other examples.

Turning now to the figures, FIG. 1A illustrates a cross-sectional view of an example display device 100 depicting an adhesive sealant 108 around a portion of a bonding layer 106. FIG. 1B illustrates the cross-sectional view of example display device 100 of FIG. 1A, depicting additional features. Example display device 100 can include, but not limited to, a notebook computer, tablet personal computer (PC) , smartphone, audio and video devices (e.g., stereo equipment and televisions) , or any other device that enables touch interactions.

Display device 100 may include a protective panel 102, a display panel 104, and bonding layer 106 between protective panel 102 and display panel 104. In some examples, bonding layer 106 may be deposited on a surface of display panel 104 and/or protective panel 102, and then protective panel 102 may be attached to display panel 104 with bonding layer 106 deposited there between.

Example protective panel 102 may be a tempered glass layer or a touch panel. Example display panel 104 may be a liquid crystal display (LCD) or an organic light-emitting diode (OLED) display. Bonding layer 106 may include an OCA. Example OCA may include a liquid OCA or a thin film OCA.

Further, display device 100 may include an adhesive sealant 108 formed by applying a liquid sealant around a portion (i.e., along at least one side) of bonding layer 106 between protective panel 102 and display panel 104. The liquid sealant may provide a solid seal in a cured state. The hardness of adhesive sealant 108 may be greater than hardness of bonding layer 106.

Example adhesive sealant 108 may include a room temperature vulcanization silicone sealant. In some examples, adhesive sealant 108 may include any other material such that the material can be able to fill the gap between protective panel 102 and display panel 104 with liquidity and can provide a solid/hard seal in a cured state.

As shown in FIG. 1B, a surface of display panel 104 to which bonding layer 106 is bonded can be a polarizing layer 110. In one example, polarizing layer 110 may be attached onto a light extraction side of display panel 104. Further as shown in FIG. 1B, display device 100 may include an air gap 112 formed around bonding layer 106 between protective panel 102 and display panel 104. Adhesive sealant 108 may be formed around the portion of bonding layer 106 to fill air gap 112 between protective panel 102 and display panel 104 after bonding layer 106.

In one example, adhesive sealant 108 may be formed around bonding layer 106 along sides of display device 100 that cause ripple during touch interactions. For example, in notebook computers, ripple may appear around shorter-side regions of display device 100 during touch interactions. In this case, adhesive sealant 108 can be applied around bonding layer 106 on the shorter-side regions of display device 100 such that adhesive sealant 108 may form an interface between protective panel 102 and display panel 104 on the shorter-side regions.

In one example, a thickness of adhesive sealant 108 may be equal to a thickness of bonding layer 106 in a direction from display panel 104 to protective panel 102 (e.g., as shown in FIG. 1B) . In the example shown in FIG. 1B, the width of polarizing layer 110 can be greater than the width of bonding layer 106 in the direction between the opposite edge regions (e.g., shorter-side regions) . In another example, a thickness of adhesive sealant 108 may be equal to a combined thickness of bonding layer 106 and polarizing layer 110 in the direction from display panel 104 to protective panel 102 (e.g., as shown in FIG. 1A) . In the example shown in FIG. 1A, the width of polarizing layer 110 can be less than or equal to the width of bonding layer 106 in the direction between the opposite edge regions (e.g., shorter-side regions) .

FIG. 2A illustrates a cross-sectional view of an example display device 200 depicting an adhesive sealant 208 along at least one side of bonding layer 206 covering an outline dimension of display panel 204. FIG. 2B illustrates the cross-sectional view of example display device 200 of FIG. 2A, depicting additional features.

Display device 200 may include a display panel 204 that displays an image, a window assembly 202 on an upper surface of display panel 204, and a bonding layer 206 disposed between window assembly 202 and display panel 204 to couple display panel 204 and window assembly 202. Bonding layer 206 may cover a display area 224 of display panel 204. As shown in FIG. 2B, window assembly 202 may include a window member 210 and a touch panel 212 disposed between window member 210 and display panel 204. For example, touch panel 212 may be attached/bonded to window member 210 using an adhesive 216 (e.g., OCA) .

In one example, a first surface of bonding layer 206 may be attached to touch panel 212 and a second surface of bonding layer 206 may be attached to display panel 204. In another example, bonding material (e.g., 206) may be deposited on a surface of display panel 204 and/or touch panel 212, and then touch panel 212 may be attached to display panel 204 with bonding material deposited there between. As shown in FIG. 2B, the second surface of bonding layer 206 may be attached to a polarizing layer 214 of display panel 204. Example bonding layer 206 may include OCA.

Furthermore, display device 200 may include other electronic components, such as a driving circuit board disposed on a rear surface (e.g., opposite to light extraction side) of display panel 204 and electrically connected to display panel 204.

Further, display device 200 may include an adhesive sealant 208 formed by applying a liquid sealant between window assembly 202 and display panel 204 to cover a non-display area 222 of display panel 204. The liquid sealant may form a solid seal in a cured state. Example adhesive sealant may be a room temperature vulcanization silicone sealant. In one example, display device 200 may include an air gap around bonding layer 206 between window assembly 202 and display panel 204. Adhesive sealant 208 may be formed on non-display area 222 between window assembly 202 and display panel 204 to fill the air gap (e.g., till the outline dimension of display panel 204) . In one example, adhesive sealant 208 may cover opposite edge regions in non-display area 222, for example, shorter-side regions 220 of display device 200 as shown in FIG. 2C.

In one example, adhesive sealant 208 may cover non-display area 222, a part of non-display area 222, or any other cases as long as adhesive sealant 208 can be disposed on non-display area 222 and can provide support. Display area 224 may refer to an area of display panel 204 used for display and non-display area 222 may refer to an area of display panel 204 except display area 224.

FIG. 2C illustrates an exploded perspective view of example display device 200, such as shown in FIG. 2A. Particularly, FIG. 2C depicts shorter-side regions 220 of display device 200 and long-side regions 218 of display device 200. Example display device 200 may be a notebook/tablet computer. In this example, adhesive sealant 208 can be applied along shorter-side regions 220 between window member 210 and display panel 204 as ripple phenomena may happen towards shorter-side regions 220 during touch interactions.

In other instances, adhesive sealant 208 may cover at least two opposite edge regions in non-display area 222. Non-display area 222 may include two opposite long-side regions 218 and two opposite short-side regions 220. In one example, adhesive sealant 208 covering at least the two opposite edge regions in non-display area 222 may refer to covering two opposite long-side regions 218 in non-display area 222 or two opposite short-side regions 220 in non-display area 222.

In another example, adhesive sealant 208 may also cover three edge regions in non-display area 222. For instance, adhesive sealant 208 may cover two opposite short-side regions and one long-side region in non-display area 222, or adhesive sealant 208 may cover two opposite long-side regions and one short-side region in non-display area 222. In such cases, other circuitry of display panel and touch panel can be connected from at least one remaining edge region (e.g., long-side region) that is not sealed. In other examples, display device 200 may also be in other shape. In this case, adhesive sealant 208 may be formed around the portion of bonding layer 206 that cause ripple during touch interactions.

The hardness of adhesive sealant 208 between display panel 204 and window assembly 202 may be greater than the hardness of bonding layer 206. Therefore, when display device 200 is applied by an external force, adhesive sealant 208 can provide a good supporting function so as to cancel out at least a part of the external force. In this case, the stress produced by display device 200 can be reduced, and hence the stress on the liquid crystals can be reduced. Therefore, the problem of reduced display quality caused by the water wave phenomenon that touch display device 200 tends to generate can be avoided.

FIG. 3 is a flow chart 300 illustrating an example method for forming a seal around a bonding material between a touch panel and a display panel. At 302, the touch panel may be attached to the display panel by disposing the bonding material between the touch panel and the display panel. The bonding material may include an OCA. For example, the OCA may be a liquid OCA or a thin film OCA.

At 304, a liquid sealant may be applied into at least a portion of an air gap formed around the bonding material between the touch panel and the display panel. Example liquid sealant may be a room temperature vulcanization glue. In one example, the liquid sealant may be applied into at least the portion of the air gap around a perimeter of the bonding material towards sides of the display device that cause ripple during touch interactions.

At 306, the liquid sealant may be cured to form a seal around the portion of the bonding material between the touch panel and the display panel. The liquid sealant may provide a solid seal in a cured state. In one example, the liquid sealant may be cured by exposure to ultraviolet (UV) light for a predetermined time, for instance, in a range of 2-5 minutes.

Examples described herein may be used in any touch-enabled display devices such as personal computers, microcomputers, minicomputers, desktop computers, notebook computers, mobile telephones, personal computing or scheduling devices, personal communication devices, tablet computing devices, digital entertainment devices such as MPEG Layer-3 (MP3) players or cameras, and the like.

It may be noted that the above-described examples of the present solution are for the purpose of illustration only. Although the solution has been described in conjunction with a specific embodiment thereof, numerous modifications may be possible without materially departing from the teachings and advantages of the subject matter described herein. Other substitutions, modifications and changes may be made without departing from the spirit of the present solution. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

The terms “include, ” “have, ” and variations thereof, as used herein, have the same meaning as the term “comprise” or appropriate variation thereof. Furthermore, the term “based on” , as used herein, means “based at least in part on. ” Thus, a feature that is described as based on some stimulus can be based on the stimulus or a combination of stimuli including the stimulus.

The present description has been shown and described with reference to the foregoing examples. It is understood, however, that other forms, details, and examples can be made without departing from the spirit and scope of the present subject matter that is defined in the following claims.

Claims

A display device， comprising：

a protective panel；

a display panel；

a bonding layer between the protective panel and the display panel； and

an adhesive sealant formed by applying a liquid sealant around a portion of the bonding layer between the protective panel and the display panel， the liquid sealant providing a solid seal in a cured state.
The display device of claim 1， wherein the protective panel is a tempered glass layer or a touch panel， and wherein the display panel is a liquid crystal display (LCD) or an organic light-emitting diode (OLED) display.
The display device of claim 1， wherein the bonding layer comprises an optically clear adhesive， and wherein the optically clear adhesive comprises a liquid optically clear adhesive or a thin film optically clear adhesive.
The display device of claim 1， wherein the adhesive sealant is a room temperature vulcanization silicone sealant， and wherein the adhesive sealant is formed around the bonding layer along sides of the display device that cause ripple during touch interactions.
The display device of claim 1， comprising an air gap formed around the bonding layer between the protective panel and the display panel， wherein the adhesive sealant is formed around the portion of the bonding layer to fill the air gap.
The display device of claim 1， wherein a surface of the display panel to which the bonding layer is bonded is a polarizing layer， and wherein the polarizing layer is attached onto a light extraction side of the display panel.
A display device， comprising：

a display panel that displays an image；

a window assembly on an upper surface of the display panel；

a bonding layer disposed between the window assembly and the display panel， the bonding layer covering a display area of the display panel； and

an adhesive sealant formed by applying a liquid sealant between the window assembly and the display panel to cover a non-display area of the display panel， wherein the liquid sealant forms a solid seal in a cured state.
The display device of claim 7， wherein the window assembly comprises：

a window member； and

a touch panel between the window member and the display panel， wherein a first surface of the bonding layer is attached to the touch panel and a second surface of the bonding layer is attached to the display panel.
The display device of claim 7， wherein the bonding layer comprises an optically clear adhesive， and wherein the adhesive sealant is a room temperature vulcanization silicone sealant.
The display device of claim 7， comprising an air gap around the bonding layer between the window assembly and the display panel， wherein the adhesive sealant is formed on the non-display area between the window assembly and the display panel to fill the air gap， and wherein the adhesive sealant covers opposite edge regions in the non-display area.
A method of forming a display device， comprising：

attaching a touch panel to a display panel by disposing a bonding material between the touch panel and the display panel；

applying a liquid sealant into at least a portion of an air gap formed around the bonding material between the touch panel and the display panel； and

curing the liquid sealant to form a seal around the portion of the bonding material between the touch panel and the display panel， the liquid sealant providing a solid seal in a cured state.
The method of claim 11， wherein applying the liquid sealant into at least the portion of the air gap around the bonding material， comprises：

applying the liquid sealant into at least the portion of the air gap around a perimeter of the bonding material towards sides of the display device that cause ripple during touch interactions.
The method of claim 11， wherein the bonding material comprises an optically clear adhesive， and wherein the optically clear adhesive comprises a liquid optically clear adhesive or a thin film optically clear adhesive.
The method of claim 11， wherein the liquid sealant is a room temperature vulcanization glue.
The method of claim 11， wherein the liquid sealant is cured by exposure to ultraviolet (UV) light for a predetermined time， and wherein the predetermined time is in a range of 2-5 minutes.