CN111913603A - Force sensing module - Google Patents

Abstract

The invention discloses a force sensing module. The force sensing module includes a force sensing device, a flexible display device, and a rigid material layer. The flexible display device is located on the force sensing device. The rigid material layer is located between the flexible display device and the force sensing device.

Description

force sensing module

technical field

The present invention relates to the field of sensing, in particular to a force sensing module.

Background technique

It has become a trend for electronic equipment to be equipped with force sensing (force sensing) devices. The force sensing device includes multiple pressure sensing (pressure sensing) units. When the pressure sensing units sense the pressure generated by the user's touch operation When the pressure-sensing unit is pressed, a certain deformation will occur, which will cause the electrical signal output by the pressure-sensitive unit to change, and then the magnitude of the electrical signal is detected to calculate and obtain the pressure on the pressure-sensitive unit. Through the detection of the pressure, the functions of electronic devices that match different pressure values can be designed. For example, the same touch point can be matched with multiple functions under different pressures. In this way, the functions of electronic products can be further enriched and new functions can be brought to users. experience.

On the other hand, flexible devices (such as display devices and touch devices) have the characteristics of being light, thin and bendable, and have been widely used in various electronic devices. However, when the electronic device is designed with both a force sensing device and a flexible device, when the electronic device is pressed by the user, the force sensing device will deform too much due to the flexibility of the flexible device, and further Weakening the resulting signal value and resulting in a poor linear relationship between the signal value and the magnitude of the pressure experienced, these problems will reduce the accuracy of pressure sensing. Therefore, the problems of the force sensing device due to the characteristics of the flexible device still need to be further improved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a force sensing module, a rigid material layer is arranged between the force sensing module and the flexible device, so as to increase the signal strength measured by the force sensing module and improve the signal value The linearity of the relationship with the amount of pressure applied. In this way, the actual pressure generated by the user-controlled operation can be accurately detected. In addition, this layer of rigid material can also protect the flexible device from damage.

To achieve the above objective, the present invention provides a force sensing module. The force sensing module includes a force sensing device, a flexible display device, and a rigid material layer. The flexible display device is located on the force sensing device. The rigid material layer is located between the flexible display device and the force sensing device. In some embodiments, the rigid material layer has a Young's modulus of 70-250 GPa. In some embodiments, the thickness of the rigid material layer ranges from 100 microns to 300 microns. In some embodiments, the rigid material layer includes stainless steel, glass, acrylic, or a combination thereof. In some embodiments, the above-mentioned flexible display device is an organic light emitting diode display device. In some embodiments, the force sensing module further includes a first adhesive layer and a second adhesive layer, wherein the force sensing device is attached to the first surface of the rigid material layer through the first adhesive layer, and the flexible display device It is attached to the second surface of the rigid material layer through the second adhesive layer. In some embodiments, the force sensing module further includes a cover layer and a third adhesive layer, wherein the cover layer is attached to the flexible display device through the third adhesive layer. In some embodiments, the above-mentioned third adhesive layer includes optically clear adhesive. In some embodiments, the force sensing module further includes a touch panel, wherein the above-mentioned flexible display device is disposed between the touch panel and the force sensing device. In some embodiments, the force sensing module further includes a touch sensing layer for detecting the touch position, and the touch sensing layer is embedded in the flexible display device. In some embodiments, the above-mentioned force sensing device includes a substrate and a plurality of pressure-sensing units disposed on the substrate, wherein each pressure-sensing unit includes four resistors with the same resistance value, and the four resistors form a Wheatstone bridge .

The present invention provides another force sensing module. The force sensing module includes a force sensing device, a flexible touch device, and a rigid material layer. The flexible touch device is located on the force sensing device. The rigid material layer is located between the flexible touch device and the force sensing device. In some embodiments, the rigid material layer has a Young's modulus of 70-250 GPa. In some embodiments, the thickness of the rigid material layer ranges from 100 microns to 300 microns. In some embodiments, the rigid material layer includes stainless steel, glass, acrylic, or a combination thereof. In some embodiments, the force sensing module further includes a first adhesive layer and a second adhesive layer, wherein the force sensing device is attached to the first surface of the rigid material layer through the first adhesive layer, and the flexible touch The device is attached to the second surface of the rigid material layer by a second adhesive layer. In some embodiments, the above-mentioned flexible touch device further includes a cover layer, at least one touch sensing layer and a third adhesive layer, wherein the touch sensing layer is attached to the cover layer through the third adhesive layer. In some embodiments, the above-mentioned third adhesive layer includes optically clear adhesive. In some embodiments, the flexible touch device further includes a cover layer and at least one touch sensing layer, and the touch sensing layer is directly formed on the surface of the cover layer. In some embodiments, the above-mentioned force sensing device includes a substrate and a plurality of pressure-sensing units disposed on the substrate, wherein each pressure-sensing unit includes four resistors with the same resistance value, and the four resistors form a Wheatstone bridge .

The force sensing module of the embodiment of the present invention can be applied to various types of force sensing fields. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, several embodiments are given below, and combined with the above The attached drawings are described in detail as follows.

Description of drawings

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various features are not drawn to scale and are illustrative only. In fact, the dimensions of elements may be arbitrarily enlarged or reduced to clearly represent the features of the invention.

1 is a schematic cross-sectional view of a force sensing module according to some embodiments of the present invention;

2 is a schematic cross-sectional view of a force sensing device in a force sensing module according to some embodiments of the present invention;

3 is a schematic diagram of an equivalent circuit of a pressure sensing unit in a force sensing device according to some embodiments of the present invention;

4 is another embodiment of the present invention, illustrating a schematic cross-sectional view of a force sensing module;

FIG. 5 is another embodiment of the present invention, illustrating a schematic cross-sectional view of a force sensing module.

Symbol Description

10, 20～Force sensing module

100～Force Sensing Device

101～Substrate

103～Pressure Sensing Unit

103'～Secondary pressure sensing unit

110～The first adhesive layer

120～Rigid material layer

120A～First surface

120B～Second surface

130～Second adhesive layer

140～Flexible display device

150～Third adhesive layer

160～Cover

170～Touch Sensing Layer

180～touch panel

240～Flexible touch device

A, B, C, D ~ electrical connection point

R ₁ , R ₂ , R ₃ , R ₄ ～resistance

VEX～Power

U ₀ ～Output voltage

Detailed ways

The following disclosure provides many different embodiments or examples to illustrate different components of embodiments of the invention. The following will disclose specific examples of the various components of the present specification and their arrangement, so as to simplify the description of the present invention. Of course, these specific examples are not intended to limit the invention. For example, if the content of the invention below in this specification describes that the first part is formed on or above the second part, it means that it includes embodiments in which the first and second parts are formed in direct contact, and also includes further embodiments. Additional components may be formed between the first and second components described above, the first and second components being embodiments that are not in direct contact. Furthermore, the various examples in the description may use repeated reference symbols and/or wording. These repeated symbols or words are used for simplicity and clarity, and are not used to limit the relationships between the various embodiments and/or the configurations.

Furthermore, for convenience in describing the relationship of one element or component to another element or component(s) in the drawings, spatially relative terms such as "below", "below", "lower", "above" may be used , "upper" and similar terms. In addition to the orientation depicted in the figures, spatially relative terms also encompass different orientations of the device in use or operation. When the device is turned in a different orientation (eg, rotated 90 degrees or otherwise), the spatially relative adjectives used therein will also be interpreted in accordance with the turned orientation.

Here, the terms "about", "approximately" and "approximately" generally mean within 20%, preferably within 10%, and more preferably within 5% of a given value or range, or within 3% Within %, or within 2%, or within 1%, or within 0.5%. It should be noted that the quantities provided in the specification are approximate quantities, that is to say, “about”, “approximately” and “approximately” can still be implied without the specific description of “about”, “approximately” and “approximately”. roughly" meaning.

Although the steps in some of the described embodiments are performed in a particular order, the steps may also be performed in other logical orders. In different embodiments, some of the described steps may be replaced or omitted, and some other operations may also be performed before, during, and/or after the steps described in the embodiments of the present invention. Other features may be added to the force sensing module in the embodiments of the present invention. In different embodiments, some features may be replaced or omitted.

FIG. 1 is a schematic cross-sectional view of a force sensing module 10 according to some embodiments of the present invention. The force sensing module 10 of this embodiment includes a force sensing device 100 , a rigid material layer 120 and a flexible display device 140 . The force sensing device 100 is disposed under the flexible display device 140 , and a rigid material layer 120 is disposed between the force sensing device 100 and the flexible display device 140 . The force sensing module 10 of this embodiment has a display function. In the embodiment of the present invention, the rigid material layer 120 is additionally disposed between the force sensing device 100 and the flexible display device 140 , which can improve the force feeling affected by the deformation of the flexible display device 140 when pressed. The strain of the force sensing device 100 is increased, the signal sensed by the force sensing device 100 is enhanced, and the relationship between the value of the sensed signal and the magnitude of the pressure exerted presents a linear relationship. In this way, the actual pressure generated by the user-controlled operation can be accurately detected. In addition, the rigid material layer 120 can also protect the flexible display device 140 from being damaged.

In some embodiments, the rigid material layer 120 described above may have a Young's modulus in the range of about 70 GPa to about 250 GPa, eg, about 190 GPa to about 210 GPa. In some embodiments, the rigid material layer 120 may be or include stainless steel (SUS), glass, acrylic, or a combination thereof. In some embodiments, the thickness of the rigid material layer 120 ranges from 100 microns to 300 microns, for example, from about 150 microns to about 200 microns. It is worth mentioning that, when the thickness of the rigid material layer 120 is too thin (for example, less than about 100 microns), the rigid material layer 120 may not be able to provide sufficient rigidity, so that the strain linearity of the force sensing device 100 cannot be effectively improved. This in turn reduces the sensitivity of pressure sensing. When the thickness of the rigid material layer 120 is too thick (eg, greater than about 300 microns), the force sensing device 100 may not be able to effectively generate strain, thereby causing the pressure sensing function to fail.

In some embodiments, the flexible display device 140 may be an organic light-emitting diode (OLED) display device.

In some embodiments, as shown in FIG. 1 , the above-mentioned rigid material layer 120 has an opposite first surface 120A and a second surface 120B, wherein the force sensing device 100 is attached to the rigid material layer 120 through the first adhesive layer 110 . The first surface 120A, and the flexible display device 140 is attached to the second surface 120B of the rigid material layer 120 through the second adhesive layer 130 . The first and second adhesive layers 110 and 130 may include optical clear adhesives (OCA), such as pressure-sensitive optical adhesives, light-curable optical adhesives, or other suitable optical clear adhesives. The above-mentioned pressure-sensitive optical adhesive means that it can be adhered to the desired bonding layer by applying appropriate pressure (for example, using a roller) to generate adhesive force. Pressure-sensitive optical adhesives can be divided into acrylic pressure-sensitive adhesives and rubber-based pressure-sensitive adhesives according to their components. The above-mentioned light-curable optical adhesive is a liquid optical adhesive, which is irradiated with light (eg, ultraviolet light) to cure the liquid optical adhesive, such as an ultraviolet-curable optical adhesive. In some embodiments, the light-curable optical adhesive can also be heated or provided with humidity to cure the liquid optical adhesive, such as ultraviolet heat-curable optical adhesive, ultraviolet humidification-curable optical adhesive, and the like. The first and second adhesive layers 110 and 130 may be the same or different materials. In some embodiments, the first adhesion layer 110 has a thickness ranging from about 25 microns to about 150 microns, eg, about 125 microns; and the second adhesion layer 130 has a thickness ranging from about 20 microns to about 50 microns, eg, about 40 microns.

In some embodiments, the force sensing module 10 may include a cover layer 160 disposed on the flexible display device 140 , wherein the cover layer 160 is adhered to the flexible device 140 through the third adhesive layer 150 The surface on the side away from the rigid material layer 120 as shown in FIG. 1 . The cover layer 160 can protect the flexible display device 140 or other elements of the force sensing module 10 thereunder. In some embodiments, the cap layer 160 may be or include a hard light transmissive material, such as calcium aluminosilicate glass, soda lime glass, sapphire, transparent polymers, others suitable materials, or a combination of the above. In some embodiments, the cap layer 160 may have a thickness ranging from about 400 microns to about 2000 microns (please confirm).

In some embodiments, the third adhesive layer 150 may be optically clear adhesive (OCA), such as pressure-sensitive optical adhesive, photocurable optical adhesive, or other suitable optically transparent adhesive. In some embodiments, the third adhesive layer 150 with a refractive index close to that of the cap layer 160 may be selected. For example, if the cover layer 160 is a common glass with a refractive index approximately equal to 1.5, the third adhesive layer 150 can be selected from an optically clear adhesive with a refractive index close to 1.5. In some embodiments, the third adhesion layer 150 may have a thickness ranging from about 25 microns to about 150 microns.

Please refer to FIG. 2 , which is a schematic cross-sectional view of the force sensing device 100 in the force sensing module 10 according to some embodiments of the present invention. The force sensing device 100 of this embodiment includes a substrate 101 and a plurality of pressure sensing units 103 formed on the surface of the substrate 101 . When the pressure sensing module 10 is pressed with a finger, the volume of the pressure sensing unit 103 will change due to the action of pressure, thereby affecting the resistance value of the pressure sensing unit 103 .

In some embodiments, the above-mentioned substrate 101 may be a flexible substrate, such as polyimide (PI), polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene - Styrene (acrylonitrile butadiene styrene, ABS), polyethylene terephthalate (polyethyleneterephthalate, PET), polyvinyl chloride (polyvinyl chloride, PVC), polycarbonate (polycarbonate, PC), polyethylene (polyethylene, PE) ), poly(methyl methacrylate) (PMMA), polytetrafluoroethylene (PTFE), similar materials, or a combination of the above. In some embodiments where the force sensing device 10 is applied to a non-flexible device, the substrate 101 may be a rigid substrate such as glass, tempered glass, sapphire glass, similar materials, or combinations thereof.

FIG. 3 is a schematic diagram of an equivalent circuit of the pressure sensing unit 103 in the force sensing device 100 . In some embodiments, each pressure sensing unit 103 may include four secondary pressure sensing units 103 ′, and each secondary pressure sensing unit 103 ′ corresponds to a resistor R ₁ , a resistor R ₂ , a resistor R ₃ and a resistor R ₄ with the same resistance value . The above _four resistors are electrically connected to form _a bridge, wherein the resistor R1 and the resistor R2 are connected in series, the resistor _R3 and the resistor R4 are connected in series, and the _two series circuits are connected in parallel to form a Wheatstone bridge. The Wheatstone bridge has the effect of temperature compensation, which helps to reduce the difference in signal sensing of the pressing force and the magnitude of the pressing force generated by the force sensing device under the influence of the ambient temperature, thereby improving the problem of distortion in the sensing of the magnitude of the pressing force signal. .

As shown in FIG. ₃ , _a power supply _VEX is loaded between the electrical connection point B of the resistor R1 and the resistor _R3 and the electrical connection point D _of the resistor R4 and the resistor _R2 , and the electrical connection between the resistor R1 and the resistor R2 An output voltage U ₀ is generated between the point A and the electrical connection point C of the resistor R ₃ and the resistor R ₄ , and the voltage U ₀ corresponds to the pressing force value.

In some embodiments, the pressure-sensing unit 103 (ie, the Wheatstone bridge) may include two non-adjacent resistors (eg, resistor R ₁ and resistor R 1 ) with pattern shapes in the same first extending direction (eg, X direction). R ₄ ), and two other non-adjacent resistors (eg, resistor R ₂ and resistor R ₃ ) having the same pattern shape in the second extension direction (eg, Y direction). The above-mentioned first extending direction is inconsistent with the second extending direction, so that the output detection signal can be larger. In a specific embodiment, the first extension direction and the second extension direction are arranged to be perpendicular to each other.

_In some embodiments, the _two resistors with the same extending direction _of the pattern shape may be distributed diagonally (for example, the resistors R1 and R4 are distributed diagonally, and the resistors R2 and _R3 are distributed diagonally). , to improve the accuracy of force sensing. In some embodiments, the pattern shape of the pattern shape with the resistors with the first extension direction after the plane is rotated by 90° is the same as or mirror-symmetrical with the pattern shape of the resistors with the second extension direction, which can ensure the stability of the Wheatstone bridge. while simplifying the manufacturing process steps.

In other embodiments of the present invention, under the condition that the resistance values of the resistor R ₁ , the resistor R ₂ , the resistor R ₃ and the resistor R ₄ are all the same, the resistor R ₁ , the resistor R ₂ , the resistor R ₃ and the resistor R The pattern shapes of ₄ can be the same or different.

Referring to FIG. 4 , according to another embodiment of the present invention, a schematic cross-sectional view of the force sensing module 10 is shown. This embodiment is substantially the same as that of the embodiment in FIG. 1 , except that the present embodiment further includes a touch sensing layer 170 disposed between the cover layer 160 and the flexible display device 140 . The combination of the touch sensing layer 170 and the cover layer 160 together constitute the touch panel 180 , so that the force sensing module 10 of this embodiment has touch and display functions. The above-mentioned touch sensing layer 170 is used for sensing the touch position of the user.

In this embodiment, the touch sensing layer 170 is directly formed on the upper surface of the flexible display device 140 , and the cover layer 160 is attached to the touch sensing layer 170 through the third adhesive layer 150 . In other embodiments, the touch sensing layer 170 may also be directly formed on the lower surface of the cover layer 160 first, and then attached to the upper surface of the flexible display device 140 through the third adhesive layer 150 . In such an embodiment, the touch panel 180 is an on-cell structure, and the cover layer 160 and the touch sensing layer 170 may be composed of, for example, a single glass solution (OGS) touch control panel, GFF (glass-film-film) touch panel, GF (glass-film) touch panel or GF2 touch panel, in other words, the touch sensing layer 170 does not limit the sensing electrode layer ( Layer structure design of substrate (not shown) and substrate (not shown). In other embodiments, the touch panel may also be an in-cell structure, that is, the touch sensing layer 170 is embedded in the flexible display device 140 .

FIG. 5 is a schematic cross-sectional view of the force sensing module 20 according to other embodiments of the present invention. In this embodiment, except that the flexible device in the force sensing module 20 is a flexible touch device 240 , this embodiment is similar to the previous embodiment in FIG. 1 . Details of this embodiment similar to the previously described embodiments will not be repeated here.

In this embodiment, the force sensing module 20 includes the flexible touch device 240 , the rigid material layer 120 , and the force sensing device 100 in sequence from top to bottom. The force sensing device 100 of the force sensing module 20 is similar to the aforementioned force sensing device 100 of the force sensing module 10 in FIGS. 1 and 4 , and details are not described herein again. Similarly, the rigid material layer 120 has a first surface 120A and a second surface 120B, wherein the force sensing device 100 is attached to the first surface 120A of the rigid material layer 120 through the first adhesive layer 110 , and the flexible touch device 240 is attached to the second surface 120B of the rigid material layer 120 through the second adhesive layer 130 .

In this embodiment, the flexible touch device 240 includes a cover layer 160 , at least one touch sensing layer 170 and a third adhesive layer 150 , and the touch sensing layer 170 is attached to the cover layer through the third adhesive layer 150 160, wherein the number of layers of the sensing electrode layer 170 is not limited here. If a multi-layer structure is used, the layers are electrically insulated by insulating layers/films (not shown). In other embodiments, the flexible touch device 240 includes a cover layer 160 and at least one touch sensing layer 170 , wherein the touch sensing layer 170 is a single-layer structure and is directly formed on the cover layer 160 . lower surface.

According to the above embodiment, the rigid material layer 120 may be additionally disposed between the force sensing device 100 of the force sensing module 10 and the flexible device (eg, the flexible display device 140 and the flexible touch device 240 ). In order to enhance the signal detected by the force sensing device 100, the relationship between the value of the sensed signal and the magnitude of the pressure exerted presents a linear relationship. In this way, the actual pressure generated by the user-controlled operation can be accurately detected. In addition, the rigid material layer 120 can also protect the flexible device from damage.

In addition, the pressure-sensing unit 103 of the force-sensing device 100 may include a Wheatstone bridge composed of four resistors with the same resistance value, which has the advantages of temperature compensation and enhanced voltage signal, which helps to reduce the stress of the force-sensing device 100 in the Due to the influence of the ambient temperature, the difference in the signal sensing of the magnitude of the pressing force is improved, thereby improving the problem of distortion in the sensing of the magnitude of the pressing force.

The force sensing module of the present invention can be applied to various electronic devices, such as mobile and portable devices (such as mobile phones, e-book readers), wearable electronic devices (such as watches), interactive multimedia kiosks, etc. .

It should be understood that, although FIG. 1 , FIG. 4 and FIG. 5 only show that the above-mentioned force sensing module can be designed with a flexible display device or a flexible touch device, in other embodiments, the embodiments of the present invention The force sensing module can also be matched with other types of flexible devices to compensate for the signal detection problem caused by the characteristics of the flexible devices.

The features of several embodiments of the present invention are briefly described above, so that those skilled in the art can more easily understand the present invention. Anyone with ordinary knowledge in the technical field should understand that this specification can easily be used as a basis for modification or design of other structures or manufacturing processes, so as to achieve the same purpose and/or obtain the same advantages of the embodiments of the present invention. Anyone with ordinary knowledge in the technical field can also understand that the structures or manufacturing processes equivalent to the above do not depart from the spirit and protection scope of the present invention, and can be modified without departing from the spirit and scope of the present invention. Substitution and Retouch.

Claims (20)

1. A force sensing module, comprising

A force sensing device;

a flexible display device disposed on the force sensing device; and

and the rigid material layer is arranged between the flexible display device and the force sensing device.

2. The force sensing module of claim 1, wherein the rigid material layer has a young's modulus of 70-250 GPa.

3. The force sensing module of claim 1, wherein the layer of rigid material has a thickness in a range of 100 microns to 300 microns.

4. The force sensing module of claim 1, wherein the rigid material layer comprises stainless steel, glass, acrylic, or a combination thereof.

5. The force sensing module of claim 1 wherein the flexible display device is an organic light emitting diode display device.

6. The force sensing module of claim 1, further comprising a first adhesive layer and a second adhesive layer, wherein the force sensing device is attached to the first surface of the rigid material layer via the first adhesive layer, and the flexible display device is attached to the second surface of the rigid material layer via the second adhesive layer.

7. The force sensing module of claim 1, further comprising a cover layer and a third adhesive layer, wherein the cover layer is attached to the flexible display device via the third adhesive layer.

8. The force sensing module of claim 7, wherein the third adhesive layer comprises an optically clear adhesive.

9. The force sensing module of claim 1, further comprising a touch panel, wherein the flexible display device is disposed between the touch panel and the force sensing device.

10. The force sensing module of claim 1, further comprising a touch sensing layer that detects a touch location, the touch sensing layer being embedded in the flexible display device.

11. The force sensing module of claim 1, wherein the force sensing device comprises:

a substrate; and

the pressure sensing units are arranged on the substrate, each pressure sensing unit comprises four resistors with the same resistance value, and the four resistors form a Wheatstone bridge.

12. A force sensing module, comprising

A force sensing device;

a flexible touch device disposed on the force sensing device; and

and the rigid material layer is arranged between the flexible display device and the force sensing device.

13. The force sensing module of claim 12, wherein the rigid material layer has a young's modulus of 70-250 GPa.

14. The force sensing module of claim 12, wherein the layer of rigid material has a thickness in a range of 100 microns to 300 microns.

15. The force sensing module of claim 12, wherein the rigid material layer comprises stainless steel, glass, acrylic, or a combination thereof.

16. The force sensing module of claim 12, further comprising a first adhesive layer and a second adhesive layer, wherein the force sensing device is attached to the first surface of the rigid material layer via the first adhesive layer, and the flexible touch device is attached to the second surface of the rigid material layer via the second adhesive layer.

17. The force sensing module of claim 12, wherein the flexible touch device further comprises a cover layer, at least one touch sensing layer, and a third adhesive layer, wherein the touch sensing layer is attached to the cover layer through the third adhesive layer.

18. The force sensing module of claim 17, wherein the third adhesive layer comprises an optically clear adhesive.

19. The force sensing module of claim 12, wherein the flexible touch device further comprises a cover layer and at least one touch sensing layer, the touch sensing layer being formed directly on a surface of the cover layer.

20. The force sensing module of claim 12, wherein the force sensing device comprises:

a substrate; and

the pressure sensing units are positioned on the substrate, each pressure sensing unit comprises four resistors with the same resistance value, and the four resistors form a Wheatstone bridge.

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