Display device

Abstract

The display device includes: a display panel including a first region, a second region bendable from the first region, and a third region extending from the second region; the driving chip is arranged in the third area; the second region is connected with the substrate and comprises a first hole, and the first hole is overlapped with the driving chip and the third region; and a cover layer disposed in the third region, where the cover layer is in contact with one or more side surfaces of the driving chip.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2023-0062001, filed on May 12, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] An embodiment of the utility model relates to a display device. Background Art

[0004] The advancement of information technology has highlighted the importance of display devices as an interface between users and information. Therefore, the use of display devices such as liquid crystal display devices and organic light emitting display devices is on the rise.

[0005] Recently, with the development of technology, a display device including a flexible display panel bent with a predetermined curvature is being developed. Utility Model Content

[0006] Embodiments of the utility model provide a display device capable of reducing interference between a driving chip and a connection substrate and protecting the driving chip from being affected by external elements.

[0007] An embodiment of the utility model provides a display device comprising: a display panel, comprising a first area, a second area that can be bent from the first area, and a third area extending from the second area; a driving chip, arranged in the third area; a connecting substrate, comprising a first hole, wherein the first hole overlaps with the driving chip and the third area; and a covering layer, arranged in the third area, wherein the covering layer contacts one side of the driving chip.

[0008] In an embodiment, the cover layer is disposed on more than one side surface of the driving chip.

[0009] In an embodiment, the thickness of the covering layer decreases as the distance between the covering layer and the driving chip increases.

[0010] In an embodiment, the thickness of the cover layer is the same as the thickness of the driving chip.

[0011] In an embodiment, the cover layer includes a thermally conductive polymer and a heat dissipation material.

[0012] In an embodiment, the thermally conductive polymer includes polyethylenedioxythiophene, polysulfonate, polythiophene, polyaniline, polypyrrole or polyacetylene.

[0013] In an embodiment, the heat dissipation material includes aluminum, copper, silver, graphene or graphite.

[0014] In an embodiment, the adhesion between the cover layer and the driving chip is 3.5 N / cm or greater.

[0015] In an embodiment, the cover layer has a modulus of 250 MPa or greater.

[0016] In an embodiment, the moisture permeability of the cover layer is 5 g / m 3 Up to 30g / m 3 .

[0017] In an embodiment, the first hole overlaps the cover layer.

[0018] In an embodiment, the display device further includes: a first protective film disposed on a rear surface of the first region; and a second protective film disposed on a rear surface of the third region.

[0019] In an embodiment, the display device further comprises a first connection pad disposed in the third region, wherein the first connection pad is connected to a line extending from the display region of the display panel.

[0020] In an embodiment, the connection substrate further comprises a second connection pad connected to the first connection pad.

[0021] In an embodiment, the connection substrate further comprises a plurality of test points disposed in the test area.

[0022] In an embodiment, the connection substrate further includes a plurality of second holes overlapping the third region and spaced apart from each other.

[0023] In an embodiment, the second hole does not overlap the testing area.

[0024] In an embodiment, the second hole is filled with resin.

[0025] In an embodiment, the resin is in contact with the third region.

[0026] In an embodiment, the resin includes acrylic resin, urethane resin, olefin resin, imide resin, amide resin, ester resin, isocyanate resin, epoxy resin or silicone resin.

[0027] An embodiment of the utility model provides a display device, comprising: a display panel, comprising a first area, a second area that can be bent from the first area, and a third area extending from the second area, wherein when the second area is bent, the first area overlaps with the third area; a driving chip, arranged in the third area; a covering layer, arranged on the opposite side of the driving chip; and a connecting substrate, comprising an opening exposing the driving chip and the covering layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a perspective view of a display device according to an embodiment of the present utility model.

[0029] Figure 2 is a perspective view of a display device folded based on a folding axis according to an embodiment of the present invention.

[0030] Figure 3 is a perspective view of a display device folded based on a folding axis according to an embodiment of the present invention.

[0031] Figure 4 is a plan view of a display device according to an embodiment of the utility model.

[0032] Figure 5 is a cross-sectional view of a display device according to an embodiment of the present utility model.

[0033] Figure 6 is a plan view of a display device according to an embodiment of the utility model.

[0034] Figure 7 It is along Figure 6 2 is a cross-sectional view of the display device taken along the cutting line II′ shown in FIG.

[0035] Figure 8 is a schematic diagram showing a bonding defect inspection of a connection substrate. DETAILED DESCRIPTION

[0036] Hereinafter, example embodiments will now be described more fully with reference to the accompanying drawings; however, they may be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein.

[0037] The same number always indicates the same element. In the accompanying drawings, for the sake of clarity, the thickness of a particular line, layer, assembly, element or feature may be exaggerated. It will be understood that although the terms "first", "second", etc. can be used in this article to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Therefore, the "first" element discussed below may also be referred to as the "second" element.

[0038] The terms used herein are only for the purpose of describing specific embodiments and are not intended to be restrictive. Unless the context clearly indicates otherwise, as used herein, "one", "one (kind / person)", "the (said)" and "at least one (kind / person)" do not represent the limitation of quantity, and are intended to include both singular and plural. Unless the context clearly indicates otherwise, for example, "an element" has the same meaning as "at least one element". "At least one (kind / person)" is not interpreted as being limited to "one" or "one (kind / person)". "Or" means "and / or". As used herein, the term "and / or" includes any combination and all combinations of one or more related listed items.

[0039] Unless explicitly described to the contrary, the word “comprises” and variations such as “comprising”, “includes” or “including” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0040] In the specification, when an element is described as being “connected” or “coupled” to another element, the element may be “directly connected or directly coupled” to the other element or “indirectly connected or indirectly coupled” to the other element through a third element.

[0041] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. It will be understood that, in addition to the orientations depicted in the accompanying drawings, spatially relative terms are also intended to cover different orientations of the device in use or operation. For example, if the device in a drawing is turned over, the element described as being on the "lower" side of the other element will then be oriented on the "upper" side of the other element. Therefore, depending on the specific orientation of the drawing, the term "lower" can cover both "upper" and "lower" orientations. Similarly, if the device in a drawing is turned over, the element described as being "below" or "under" other elements will then be oriented "above" other elements. Therefore, the term "below..." or "under..." can cover both upper and lower orientations.

[0042] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will also be understood that, unless explicitly defined as such herein, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formalized sense.

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0044] Figure 1 is a perspective view of a display device DD according to an embodiment of the present invention.

[0045] Reference Figure 1 , the display device DD may include a plurality of areas divided in a display surface. The display surface may be divided into a display area DA and a non-display area NDA according to whether an image IM is displayed. The display area DA is an area where the image IM is displayed, and the non-display area NDA is an area where the image IM is not displayed. For example, Figure 1 The display device DD shown in FIG. 4 may be a smart phone provided in a quadrilateral shape. The display device DD may display weather information and an image IM of an icon. The non-display area NDA may be adjacent to or surround the display area DA, and may be omitted in an embodiment of the present disclosure.

[0046] The display surface may be parallel to a plane formed by the first direction DR1 and the second direction DR2. The normal direction of the display surface may indicate a third direction DR3. The third direction DR3 may indicate a thickness direction of the display device DD. The front and rear surfaces of each component of the display device DD may be determined by the third direction DR3.

[0047] The directions indicated by the first direction DR1, the second direction DR2, and the third direction DR3 may be converted into other directions. In addition, in the present specification, the phrase "viewed on a plane" may mean viewed from the third direction DR3.

[0048] The display device DD can be folded or unfolded around the folding axis FX. The folded position includes a position where the foldable display device DD is bent. Specifically, the folded position may be a position where the display device DD is bent so that a portion of the display device DD is tilted from another portion of the display device DD. For example, the display device DD may be folded or unfolded relative to the folding axis FX set in the second direction DR2. The unfolded position may be a position where a portion of the display device DD is placed side by side with another portion of the display device DD to form a substantially planar structure. Alternatively, the folded position may be a position where the angle between a portion of the display device DD and another portion of the display device DD is approximately 0 to less than 180 degrees and / or greater than approximately 180 to less than 360 degrees. The unfolded position may be a position where the angle between a portion of the display device DD and another portion of the display device DD is approximately 180 degrees.

[0049] The display device DD may include a folding area FA folded around a folding axis FX, and a first non-folding area NFA1 and a second non-folding area NFA2 spaced apart from each other, and the folding area FA is interposed between the first non-folding area NFA1 and the second non-folding area NFA2. The folding axis FX may extend in a second direction DR2. The first non-folding area NFA1 may extend from a first end of the folding area FA in a first direction DR1. The second non-folding area NFA2 may extend from a second end of the folding area FA in the first direction DR1. The first end of the folding area FA may be opposite to the second end of the folding area FA along the first direction DR1.

[0050] The upper surface DD-US of the display device DD may include a first display surface PA1 overlapping the folding area FA, a second display surface PA2 overlapping the first non-folding area NFA1, and a third display surface PA3 overlapping the second non-folding area NFA2. The lower surface DD-DS of the display device DD may be a surface facing away from the upper surface DD-US. Each of the first display surface PA1, the second display surface PA2, and the third display surface PA3 may display an image.

[0051] In the embodiments of the present disclosure, the display device DD may be a foldable display device as an example, but is not limited thereto, and the display device DD may be applied to various display devices such as flexible display devices (e.g., rollable display devices and stretchable display devices), curved display devices. In addition, the foldable display device according to the present disclosure may be used for large electronic devices (such as televisions or external billboards) and small and medium-sized electronic devices (such as mobile phones, personal computers, notebook computers, personal digital terminals, car navigation devices, game consoles, portable electronic devices, watch-type electronic devices, and cameras), etc.

[0052] Figure 2 is a perspective view of a display device DD folded based on a folding axis FX according to an embodiment of the present invention.

[0053] Reference Figure 1 and Figure 2 , the folding area FA may be folded based on the folding axis FX so that the second display surface PA2 and the third display surface PA3 face each other. The folding area FA may be folded along the first rotation direction RT1. The lower surface DD-DS of the display device DD may be exposed to the outside. In this state, the upper surface DD-US of the display device DD may not be exposed to the outside.

[0054] The display device DD may be folded along a folding axis FX, and this may be referred to as an inward fold.

[0055] Figure 3is a perspective view of a display device DD folded based on a folding axis FX according to an embodiment of the present invention.

[0056] Reference Figure 1 and Figure 3 , the folding area FA can be folded based on the folding axis FX so that the second display surface PA2 and the third display surface PA3 are exposed to the outside. The folding area FA can be folded along the second rotation direction RT2, and the upper surface DD-US of the display device DD can be exposed to the outside. In this state, the lower surface DD-DS of the display device DD may not be exposed to the outside.

[0057] In other words, the display device DD may be folded along the folding axis FX so that the second display surface PA2 of the first non-folding area NFA1 and the third display surface PA3 of the second non-folding area NFA2 face outward. This may be referred to as external folding.

[0058] Figure 4 is a plan view of a display device DD according to an embodiment of the present invention. Figure 5 is a cross-sectional view of a display device DD according to an embodiment of the present utility model. For ease of description, Figure 4 A plan view showing that the connection substrate CB is not coupled to the display panel DP.

[0059] Reference Figure 4 and Figure 5 , the display device DD may include a display panel DP, a driving chip IC, a plurality of first connection pads CP1 , a cover layer CVL and a connection substrate CB.

[0060] The display panel DP according to an embodiment of the present disclosure may be a light-emitting display panel. For example, the display panel DP may be an organic light-emitting display panel, a quantum dot light-emitting display panel, a micro light-emitting diode (LED) display panel, or a nano LED display panel.

[0061] Pixels and a plurality of lines W connected to the pixels may be disposed in the display area DA. The plurality of lines W may include data lines, power lines, control signal lines, scan lines, emission control lines, and the like.

[0062] A driving circuit that provides various signals to the pixels may be disposed in the non-display area NDA. The driving circuit may include a scan driving circuit, an emission control driving circuit, and the like.

[0063] The display panel DP may include a first area NBA1, a second area BA, and a third area NBA2. The first area NBA1, the second area BA, and the third area NBA2 may be arranged along a first direction DR1. The first area NBA1 and the third area NBA2 may be spaced apart from each other with the second area BA interposed therebetween.

[0064] The first area NBA1 may be an area for displaying an image, and may include a reference Figure 1 The areas of the folding area FA, the first non-folding area NFA1 and the second non-folding area NFA2 are described.

[0065] The second area BA may be bent in one direction. For example, the second area BA may be bent in a direction opposite to the upper surface DD-US of the display panel DP. In other words, the second area BA may be bent in a direction opposite to the third direction DR3.

[0066] The driver chip IC may be a chip integrating a circuit for driving the display panel DP. The driver chip IC may output an image signal and a drive signal for image display. The driver chip IC may be disposed in the third area NBA2 in a method such as a chip on plastic (COP) or a chip on glass (COG). The driver chip IC may be connected to the plurality of first connection pads CP1 through a plurality of wires W.

[0067] The plurality of first connection pads CP1 may be electrically connected to the plurality of second connection pads CP2 of the connection substrate CB. Therefore, the plurality of first connection pads CP1 may receive various signals for driving the display panel DP through the connection substrate CB. In addition, the plurality of first connection pads CP1 may be connected to the plurality of wires W extending from the display area DA.

[0068] The cover layer CVL may be disposed in the third area NBA2. The cover layer CVL according to an embodiment of the present disclosure may contact at least a portion of the side surface of the driver chip IC. For example, the cover layer CVL may surround the side of the driver chip IC. For example, the cover layer CVL may cover at least four sides of the driver chip IC. Therefore, the cover layer CVL may protect the driver chip IC from foreign substances such as water or moisture. To achieve this, the moisture permeability of the cover layer CVL may be 5 g / m 3 Up to 30g / m 3 In addition, since the cover layer CVL is provided, the cap provided on the connection substrate CB to protect the driver chip IC can be omitted. Therefore, the thickness of the display device DD can be reduced. In addition, the cover layer CVL can reduce the malfunction or damage of the driver chip IC caused by static electricity generated between the driver chip IC and the configuration adjacent to the driver chip IC (for example, the connection substrate CB).

[0069] like Figure 5As shown in , the thickness of the covering layer CVL according to an embodiment of the present disclosure may decrease as the distance from the driver chip IC increases. In other words, the thickness of a portion of the covering layer CVL that contacts the driver chip IC may be the same as the thickness of the driver chip IC. In addition, the thickness of a portion of the covering layer CVL that is spaced apart from the driver chip IC along the first direction DR1 may be less than the thickness of the driver chip IC. In this case, the covering layer CVL may have an inclined side wall. However, the thickness of the covering layer CVL is not limited to the above example. For example, the covering layer CVL may have the same thickness as that of the driver chip IC, and may be formed with a constant thickness.

[0070] The cover layer CVL according to an embodiment of the present disclosure may include a thermally conductive polymer and a heat dissipation material. Therefore, the cover layer CVL can effectively dissipate the heat generated from the driver chip IC. For example, the thermally conductive polymer may include at least one of polyethylene dioxythiophene (PEDOT), polysulfonate, polythiophene, polyaniline, polypyrrole, and polyacetylene. For example, the heat dissipation material may include at least one of a metal material such as aluminum, copper, and silver, graphene, and graphite. The cover layer CVL may be formed by spraying a composite material including the above-mentioned thermally conductive polymer and heat dissipation material onto the side surface of the driver chip IC by a spraying method or the like.

[0071] According to an embodiment of the present disclosure, the adhesion between the cover layer CVL and the driver chip IC may be 3.5 N / cm or greater. In addition, the modulus of the cover layer CVL may be 250 MPa or greater. Therefore, the cover layer CVL may be effectively fixed to at least a portion of the side surface of the driver chip IC.

[0072] The connection substrate CB may include a first hole CB_H1 and a plurality of second connection pads CP2 .

[0073] The connection substrate CB may overlap at least a portion of the third area NBA2. The connection substrate CB may be electrically connected to the driving chip IC through the second connection pads CP2 and the first connection pads CP1. The connection substrate CB may be a flexible printed circuit board (FPCB).

[0074] The first hole CB_H1 may overlap the driver chip IC in the third direction DR3. In addition, the first hole CB_H1 may overlap the cover layer CVL in the third direction DR3. Therefore, physical interference (or contact) between the driver chip IC and / or the cover layer CVL and the connection substrate CB may be prevented. In addition, since the first hole CB_H1 is formed in the connection substrate CB, the connection substrate CB mostly overlaps the third area NBA2, and thus an additional space for configuring a portion such as a battery may be ensured.

[0075] The plurality of second connection pads CP2 may be electrically connected to the plurality of first connection pads CP1. To achieve this, the plurality of second connection pads CP2 may be formed at positions corresponding to the plurality of first connection pads CP1. The plurality of second connection pads CP2 may be connected to the plurality of first connection pads CP1 in a chip-on-glass (FOG) method.

[0076] The display device DD may further include a first protection film PF1 and a second protection film PF2.

[0077] The first protective film PF1 may be disposed on the rear surface of the display panel DP. The first protective film PF1 may be disposed in a portion of the display device DD corresponding to the first area NBA1. In other words, the first protective film PF1 may be disposed on the rear surface of the display panel DP in the first area NBA1. The first protective film PF1 may support the first area NBA1 so that the first area NBA1 is not bent when the display panel DP is bent. The first protective film PF1 may include a polyethylene terephthalate (PET) film or the like.

[0078] The second protective film PF2 may be disposed on the rear surface of the display panel DP. The second protective film PF2 may be disposed in a portion of the display device DD corresponding to the third area NBA2. In other words, the second protective film PF2 may be disposed on the rear surface of the display panel DP in the third area NBA2. The second protective film PF2 may support the third area NBA2 so that the third area NBA2 does not bend when the display panel DP is bent. The second protective film PF2 may include a PET film or the like.

[0079] Figure 6 is a plan view of a display device DD according to an embodiment of the present utility model. For ease of description, Figure 6 A plan view showing the connection substrate CB coupled to the display panel DP. Figure 7 It is along Figure 6 2 is a cross-sectional view of the display device DD taken along the cutting line II′ shown in FIG. Figure 8 Schematic diagram showing the inspection of bonding defects of a connection substrate. Figures 6 to 8 , the same reference numerals are assigned to Figure 4 For configurations that are the same as those shown in , repeated descriptions are omitted, and differences are mainly described.

[0080] Reference Figure 6 and Figure 7 , the connection substrate CB according to the embodiment of the present disclosure may further include a test area TA, a plurality of test points TP, and a plurality of second holes CB_H2 .

[0081] The test area TA may be an area for checking a bonding defect of the connection substrate CB. For example, when the connection substrate CB is mounted on the display panel DP, the test area TA may be an area for checking whether the electrical coupling (or connection) between the connection substrate CB and the display panel DP is normally performed. To achieve this, a signal pattern for checking a bonding defect of the connection substrate CB may be formed in the test area TA. Figure 6 As shown in FIG. 1 , the test area TA may be spaced apart from the first hole CB_H1 . However, this is merely an example, and the position and number of the test area TA may vary according to inspection conditions.

[0082] A plurality of test points TP may be formed in the test area TA. The plurality of test points TP may be connected to a signal pattern formed in the test area TA. By measuring the resistance of the test area TA through the plurality of test points TP, it may be checked whether the bonding of the connection substrate CB is defective. Figure 6 In the example shown in FIG. 4 , eight test points TP are arranged on the connection substrate CB, but the number and arrangement of the test points TP are not limited to the above example.

[0083] The plurality of second holes CB_H2 according to the embodiment may be formed to overlap the third area NBA2. This is done to compensate for the step difference GAP (refer to Figure 8 ). The plurality of second holes CB_H2 may be formed not to overlap with the test area TA. However, this is merely an example, and the plurality of second holes CB_H2 may be formed to overlap with a portion of the test area TA.

[0084] The plurality of second holes CB_H2 according to an embodiment of the present disclosure may be spaced apart from each other. Figure 6 In the embodiment, the eight second holes CB_H2 are spaced apart from each other by a predetermined distance, but the number, size and spacing distance of the second holes CB_H2 are not limited to Figure 6 Those shown in .

[0085] According to an embodiment of the present disclosure, the plurality of second holes CB_H2 may be filled with a resin RE. For example, the resin RE may include at least one of an acrylic resin, a urethane resin, an olefin resin, an imide resin, an amide resin, an ester resin, an isocyanate resin, an epoxy resin, and a silicone resin. However, the present disclosure is not limited thereto, and the plurality of second holes CB_H2 may be filled with the same material as that configuring the cover layer CVL.

[0086] The resin RE according to an embodiment of the present disclosure may pass through the connection substrate CB and contact at least a portion of the third area NBA2. For example, the resin RE filled in the plurality of second holes CB_H2 may extend to contact at least a portion of the third area NBA2. As another example, the resin RE may form a gap between the display panel DP and the connection substrate CB.

[0087] Reference Figure 8 , the probe PR may be pressed onto the connection substrate CB to check for bonding defects of the connection substrate CB. The probe PR may include a probe body PB and a plurality of probe pins PP. The probe body PB may include a circuit for measuring the resistance of the test area TA. The plurality of probe pins PP may be formed at positions corresponding to the plurality of test points TP formed in the connection substrate CB. Therefore, when the probe PR is pressed onto the connection substrate CB, the plurality of probe pins PP and the plurality of test points TP may contact each other.

[0088] like Figure 8 As shown in , there may be a step difference GAP between the connection substrate CB and the display panel DP. Therefore, in the process where the probe PR is pressed to the connection substrate CB, physical interference (or contact) may occur between the connection substrate CB and the display panel DP due to the pressure applied by the probe PR. Therefore, cracks may occur in the display panel DP, and thus the display panel DP may be damaged.

[0089] According to an embodiment of the present invention, a resin RE may be formed, the resin RE contacts the third area NBA2 of the display panel DP through the plurality of second holes CB_H2 overlapping the third area NBA2, and thus may compensate for the step difference GAP between the connection substrate CB and the display panel DP. Therefore, when inspecting a bonding defect of the connection substrate CB, damage to the display panel DP may be prevented.

[0090] The present invention should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to make the present disclosure comprehensive and complete, and will fully convey the concept of the present invention to those skilled in the art.

[0091] While the present invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit or scope of the present invention as set forth in the following claims.

Claims

1. A display device, characterized in that: The display device comprises: The display panel comprises a first area, a second area capable of being bent from the first area, and a third area extending from the second area; A driving chip is arranged in the third area; A connecting substrate including a first hole, Wherein, the first hole overlaps with the driving chip and the third area; and a covering layer disposed in the third region, Wherein, the covering layer contacts one side surface of the driving chip.

2. The display device according to claim 1, characterized in that The cover layer is disposed on more than one side surface of the driving chip.

3. The display device according to claim 1, characterized in that The thickness of the covering layer decreases as the distance between the covering layer and the driving chip increases.

4. The display device according to claim 1, characterized in that The thickness of the covering layer is the same as the thickness of the driving chip.

5. The display device according to claim 1, characterized in that The first hole overlaps the cover layer.

6. The display device according to claim 1, characterized in that: The display device further includes: A first protective film disposed on a rear surface of the first region; and A second protective film is disposed on the rear surface of the third area.

7. The display device according to claim 1, characterized in that The display device further includes: A first connection pad disposed in the third region; and a second connection pad connected to the first connection pad, Wherein, the first connection pad is connected to a line extending from a display area of ​​the display panel.

8. The display device according to claim 1, characterized in that: The connection substrate further includes a plurality of test points disposed in the test area and a plurality of second holes overlapping the third area and spaced apart from each other.

9. The display device according to claim 8, characterized in that: The second hole is filled with resin.

10. The display device according to claim 9, characterized in that: The resin is in contact with the third region.

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