JP2019090913A - Display - Google Patents

Abstract

A display device capable of suppressing the generation of soot and cracks in a manufacturing process is provided. A display device (DSP) includes a liquid crystal layer (LC), a polyimide base (10), and a first insulating layer (11). The liquid crystal layer LC is electrically driven to selectively transmit light. The polyimide base material 10 has an inner surface 10A facing the liquid crystal layer LC and an outer surface 10B opposite to the inner surface 10A. A first insulating layer 11 that does not easily transmit moisture is formed between the liquid crystal layer LC and the polyimide base material 10 . At this time, the inner surface 10A is characterized by including an exposed region 10Ax exposed from the first insulating layer 11 to the outside. [Selection drawing] Fig. 3

Description

  Embodiments of the present invention relate to a display device provided with a flexible substrate.

  The flexible display device includes a substrate formed of a flexible material such as polyimide resin. The polyimide substrate is applied onto a glass substrate and cured, and then the interface is irradiated with laser light to peel off the glass substrate. If the adhesion between the glass substrate and the polyimide substrate is large, the glass substrate can not be peeled off without being irradiated with high energy laser light.

  When the energy of the laser beam is increased, the polyimide substrate may be burnt and wrinkles may occur, or the end face of the polyimide substrate may be cracked. Instead of the laser light irradiation, a polyimide laminate of a two-layer structure which can be easily peeled off between the first polyimide layer and the second polyimide layer is formed on the glass substrate, and the first polyimide layer to the second polyimide layer are formed. It has been proposed to peel off (see, for example, Patent Document 1).

JP, 2016-120629, A

  However, in the method described in Patent Document 1, the first polyimide layer remains on the glass substrate. The remaining first polyimide layer is discarded without being used. An object of the present disclosure is to provide a flexible display device which can easily peel off a glass substrate even when the energy of laser light is suppressed.

  A display device according to one embodiment includes an electro-optical layer, a polyimide base, and a passivation film. The electro-optic layer is electrically driven to form an image. The polyimide substrate has an inner surface opposite to the electro-optical layer and an outer surface opposite to the inner surface. A moisture-impermeable passivation film is formed between the electro-optic layer and the polyimide substrate. At this time, the inner surface is characterized by including an exposed region exposed to the outside from the passivation film.

FIG. 1 is a plan view showing a schematic configuration of the display device of the first embodiment. FIG. 2 is a cross-sectional view showing the structure of the display device in the display area shown in FIG. FIG. 3 is a cross-sectional view showing the structure of the display device in the non-display area shown in FIG. FIG. 4 is a flowchart showing an example of a method of manufacturing the display device of the first embodiment. FIG. 5 is a cross-sectional view schematically showing the configuration of the display device of the second embodiment. FIG. 6 is a cross-sectional view schematically showing the configuration of a modification of the display device of the second embodiment. FIG. 7 is a cross-sectional view schematically showing the configuration of the display device of the third embodiment. FIG. 8 is a cross-sectional view showing the structure in the display area of the display device of the fourth embodiment. FIG. 9 is a cross-sectional view schematically showing the configuration in the non-display area of the display device of the fourth embodiment. FIG. 10 is a flowchart showing an example of a method of manufacturing the display device of the fourth embodiment.

  Several embodiments will be described with reference to the drawings. The disclosure is merely an example, and it is naturally included within the scope of the present invention that those skilled in the art can easily conceive of appropriate changes without departing from the spirit of the invention. In addition, the drawings may be schematically represented as compared to the actual embodiment in order to clarify the description, but are merely examples and do not limit the interpretation of the present invention. In each figure, the code | symbol may be abbreviate | omitted about the same or similar element arrange | positioned continuously. Further, in the present specification and the drawings, components having the same or similar functions as or to those of the drawings already described may be denoted by the same reference symbols, and overlapping detailed descriptions may be omitted.

  In addition, in the present specification, “α includes A, B or C”, “α includes any of A, B and C”, “α is one selected from the group consisting of A, B and C The expression “including” does not exclude the case where α includes a plurality of combinations of A to C unless otherwise specified. Furthermore, these expressions do not exclude the case where α contains other elements.

First Embodiment
FIG. 1 is a plan view showing a schematic configuration of the display device DSP of the first embodiment. The display device DSP according to the first embodiment includes a flexible display panel (liquid crystal cell) PNL for displaying an image on a display surface, and an external drive circuit 4 for controlling the operation of the display panel PNL. It is. The display device DSP can be used, for example, in various devices such as a smartphone, a tablet terminal, a mobile phone terminal, a personal computer, a television receiver, an in-vehicle device, a game machine, and a wearable terminal.

  In the following description, looking from the display surface of the display panel PNL toward the back is defined as plan view. The display panel PNL may be a transmissive type that displays an image by selectively transmitting light from the back surface, or a reflective type that displays an image by selectively reflecting light incident on a display surface. It may be In the case of the transmissive type, the display panel PNL further includes a backlight BL that emits light to the back surface.

  The display panel PNL includes a first substrate SUB1 which is an array substrate, a second substrate SUB2 which is a counter substrate, a seal part SE which is an adhesive, and a liquid crystal layer LC. The second substrate SUB2 is formed in a substantially rectangular shape having first to fourth sides E1, E2, E3 and E4. The second substrate SUB2 faces the first substrate SUB1 in the thickness direction Z of the display panel PNL. The first substrate SUB1 is formed larger than the second substrate SUB2 and has a mounting area 3 exposed from the second substrate SUB2.

  The seal part SE is annularly formed along the first to fourth sides E1, E2, E3 and E4 of the second substrate SUB2, and bonds the first substrate SUB1 and the second substrate SUB2. Exposed regions 10Ax and 20Ax are formed between the first to fourth sides E1, E2, E3 and E4 and the seal part SE and at the end of the mounting region 3. The exposed areas 10Ax and 20Ax will be described in detail later with reference to FIG.

  The liquid crystal layer LC is enclosed between the first substrate SUB1 and the second substrate SUB2 inside the seal part SE. The liquid crystal layer LC is an example of an optical layer (electro-optical layer), and is electrically driven to selectively transmit light. The display surface of the display panel PNL includes a display area DA in which a plurality of pixels PX are arranged in a matrix, and a non-display area NDA in a frame shape surrounding the display area DA.

  In the non-display area NDA, various circuits for supplying signals to the pixels PX of the display area DA are formed. The mounting area 3 is included in the non-display area NDA, and extends from the first side E1 to the opposite side to the display area DA. In the mounting area 3, an external drive circuit 4 is mounted. The external drive circuit 4 is mounted with a control module CTR and the like.

  The control module CTR sequentially receives one frame of image data to be displayed on the display area DA from the main board or the like of the electronic device on which the display device DSP is mounted. The image data includes, for example, information such as the display color of each pixel PX. The control module CTR supplies a signal for driving each pixel PX to the display panel PNL based on the received image data.

  FIG. 2 is a cross-sectional view showing the structure of the display device DSP in the display area DA. In the example shown in FIG. 2, the display device DSP has a configuration corresponding to a display mode that mainly uses a transverse electric field substantially parallel to the display surface. The display device DSP may have a configuration corresponding to a display mode in which a vertical electric field perpendicular to the display surface, an electric field in the oblique direction to the display surface, or a combination thereof is used.

  As shown in FIG. 2, the first substrate SUB 1 includes a polyimide substrate (first flexible substrate) 10, first to fifth insulating layers 11, 12, 13, 14 and 15, and a semiconductor layer SC. The scanning signal line G, the video signal line S, the relay electrode Sr, the common electrode CE, the pixel electrode PE, and the alignment film 16 are provided.

  The polyimide substrate 10 is formed of a polyimide resin having flexibility, light transmission and insulation. The polyimide substrate 10 may be porous in order to enhance moisture permeability and translucency. If the polyimide substrate 10 is porous, it is easy to introduce water into the inside.

  The polyimide substrate 10 has an inner surface (first main surface) 10A facing the liquid crystal layer LC, and an outer surface (second main surface) 10B opposite to the inner surface 10A. The first insulating layer 11 covers the inner surface 10A of the polyimide substrate 10. The first insulating layer 11 is an example of a passivation film, and is formed of a passivity that is hard to transmit moisture, such as silicon nitride and silicon oxide. The first insulating layer 11, which is a passivation film, has a humidity expansion coefficient smaller than that of the polyimide substrate 10. The semiconductor layer SC is formed on the first insulating layer 11.

  The second insulating layer 12 covers the first insulating layer 11 and the semiconductor layer SC. The scanning signal line G is formed on the second insulating layer 12. The third insulating layer 13 covers the second insulating layer 12 and the scanning signal line G. The video signal line S and the relay electrode Sr are formed on the third insulating layer 13.

  The fourth insulating layer 14 covers the third insulating layer 13, the video signal line S, and the relay electrode Sr. The fourth insulating layer 14 is an organic insulating layer formed of a photosensitive resin such as an acrylic resin, for example. The fourth insulating layer 14 has a function of planarizing the unevenness of the thin film transistor, and is formed thicker than the first to third and fifth insulating layers 11, 12, 13, 15 and the alignment film 16.

  The common electrode CE is formed on the fourth insulating layer 14. The fifth insulating layer 15 covers the fourth insulating layer 14 and the common electrode CE. The pixel electrode PE is formed on the fifth insulating layer 15. The pixel electrode PE may be formed under the fifth insulating layer 15, and the common electrode CE may be formed on the fifth insulating layer 15. The alignment film 16 covers the fifth insulating layer 15 and the pixel electrode PE. The first and second contact holes CH1 and CH2 pass through the second and third insulating layers 12 and 13, respectively. The third contact hole CH3 penetrates the fourth and fifth insulating layers 14 and 15.

  The video signal line S is in contact with the semiconductor layer SC through the first contact hole CH1. The relay electrode Sr is in contact with the semiconductor layer SC through the second contact hole CH2. One of the video signal line S and the relay electrode Sr is a source electrode, and the other is a drain electrode. The semiconductor layer SC, the source electrode, and the drain electrode constitute a thin film transistor (TFT).

  The pixel electrode PE is in contact with the relay electrode Sr through the third contact hole CH3 and is electrically connected to the semiconductor layer SC. When a voltage is supplied to the pixel electrode PE via the source electrode, an electric field is formed between the pixel electrode PE and the common electrode CE, and the alignment of liquid crystal molecules in the liquid crystal layer LC is changed. Thereby, the amount of light transmitted through the liquid crystal layer LC is controlled.

  The second substrate SUB 2 includes a polyimide substrate (second flexible substrate) 20, an underlayer 21, a light shielding layer 22, a color filter layer 23, an overcoat layer 24, and an alignment film 25. ing. The color filter layer 23 may be formed on the first substrate SUB1. The polyimide substrate 20 is formed of the same polyimide resin as the polyimide substrate 10 of the first substrate SUB1 and has flexibility, light transmittance, and insulation. The polyimide substrate 20 has an inner surface (fourth main surface) 20A opposed to the inner surface 10A of the polyimide substrate 10, and an outer surface (third main surface) 20B opposite to the inner surface 20A.

  The underlayer 21 covers the inner surface 20A of the polyimide substrate 20. The underlayer 21 is formed of the same material as the insulating layer 11 and imparts rigidity so that the polyimide substrate 20 does not curl. The underlayer 21 is an example of a passivation film. The base layer 21, which is a passivation film, has a humidity expansion coefficient smaller than that of the polyimide substrate 20. The light shielding layer 22 is formed on the underlayer 21. The color filter layer 23 covers the underlayer 21 and the light shielding layer 22. The color filter layer 23 is colored in a color corresponding to the sub-pixel constituting the pixel PX.

  The overcoat layer 24 covers the color filter layer 23. The alignment film 25 covers the overcoat layer 24. The liquid crystal layer LC is disposed between the alignment films 16 and 25. The alignment films 16 and 25 align the liquid crystal molecules of the liquid crystal layer LC in a state where a voltage is not applied to the pixel electrode PE.

  The first polarizing plate PL1 is attached to the outer surface 10B of the polyimide substrate 10. In addition, when using the backlight BL which irradiates the polarized light, you may abbreviate | omit 1st polarizing plate PL1. The second polarizing plate PL2 is attached to the outer surface 20B of the polyimide substrate 20.

  FIG. 3 is a cross-sectional view showing the structure of the display device DSP in the non-display area NDA. The seal part SE includes spacers PS1 and PS2 in order to regulate the distance between the first substrate SUB1 and the second substrate SUB2. The spacer PS1 is formed on the second substrate SUB2 and protrudes in a columnar shape toward the first substrate SUB1. The spacer PS2 is formed in a frame shape along the outer shape of the seal portion SE, and prevents the flow of the seal portion SE from spreading outside the spacer PS1 when bonding the first and second substrates SUB1 and SUB2.

  The polyimide substrate 10 is formed in a substantially rectangular flat plate shape, and has an end face 10C connecting the inner surface 10A and the outer surface 10B. Similarly, the polyimide base 20 is formed in a substantially rectangular flat plate shape, and has an end face 20C connecting the inner surface 20A and the outer surface 20B. The display device DSP of the present invention is characterized in that the inner surfaces 10A and 20A of the polyimide substrates 10 and 20 include exposed regions 10Ax and 20Ax in the vicinity of the end faces 10C and 20C.

  The exposed region 10Ax is not covered by the first insulating layer 11 which is a passivation film, and is exposed to the outside. The exposed region 20Ax is not covered by the underlayer 21 which is a passivation film, and is exposed to the outside. In other words, the inner surface 10A is directed from the boundary (the outer edge 11E of the first insulating layer 11) of the area where the first insulating layer 11 which is a passivation film is formed to the end surface 10C of the polyimide substrate 10 to the polyimide substrate 10 Have an exposed exposed area 10Ax.

  Similarly, the inner surface 20A is exposed from the boundary (the outer edge 21E of the base layer 21) of the area where the base layer 21 which is a passivation film is formed toward the end face 20C of the polyimide base 20. It has a region 20Ax. The exposed region 20Ax in the vicinity of the end face 20C is partitioned, for example, between the end face 20C of the polyimide substrate 20 and the spacer PS2 of the sealing portion SE.

  Similarly, the exposed region 10Ax in the vicinity of the end face 10C is divided, for example, between the end face 10C of the polyimide substrate 10 and the spacer PS2 of the sealing portion SE at the second to fourth sides E2, E3, E4, In the area 3, it is partitioned between the end face 10C and the control module CTR.

  FIG. 4 is a flowchart showing an example of a method of manufacturing the display device DSP. A manufacturing method for manufacturing the display device DSP of the present embodiment will be described with reference to FIG. The first and second substrates SUB1 and SUB2 are formed on the glass substrate, and then peeled off from the glass substrate by irradiation with a laser beam.

  In the manufacturing method according to the present embodiment, the exposed regions 10Ax and 20Ax formed on the inner surfaces 10A and 20A are applied to the polyimide substrates 10 and 20 before irradiating the interface (the outer surfaces 10B and 20B) with the glass substrate with laser light. Moisture absorption is one of the features. The exposed regions 10Ax and 20x may be omitted as long as the polyimide substrates 10 and 20 can sufficiently absorb moisture.

  The steps ST1 to ST3 of forming the first substrate SUB1 on a glass substrate will be described. First, the material of the polyimide substrate 10 is applied to the upper surface of the glass substrate, and the applied material is cured to form the polyimide substrate 10 (first flexible substrate formation ST1). As an example, if the composition containing a polyamic acid is apply | coated to the upper surface of a glass substrate, and it heat-processes at 300-500 degreeC and imidizes, the film-form polyimide base material 10 can be formed.

  The first insulating layer 11 which is a passivation film is formed on the polyimide substrate 10. The scanning signal line G, the video signal line S, the semiconductor layer SC, the common electrode CE, the pixel electrode PE, the second to fifth insulating layers 12, 13, 14, 15 and the like are stacked on the first insulating layer 11. A circuit layer is formed (circuit layer formation ST2). The material of the alignment film 16 is coated on the circuit layer, and the coated material is cured to form the alignment film 16 (first alignment film formation ST3). Through the steps ST1 to ST3, a mother substrate including a plurality of first substrates SUB1 is obtained.

  Next, steps ST4 to ST6 for preparing the second substrate SUB2 will be described. The polyimide base 20 is formed on the glass substrate in the same manner as the step ST1 (second flexible base formation ST4). Underlayer 21 which is a passivation film is formed on polyimide substrate 20.

  A colored layer in which the above-mentioned light shielding layer 22, color filter layer 23, overcoat layer 24 and the like are laminated is formed on the base layer 21 (colored layer formation ST5). In the same manner as the step ST3, the alignment film 25 is formed on the colored layer (second alignment film formation ST6). Through steps ST4 to ST6, a mother substrate including a plurality of second substrates SUB2 is obtained.

  Next, steps ST7 and ST8 for bonding the first and second substrates SUB1 and SUB2 will be described. The material of the seal portion SE is applied to one of the mother substrates, and the liquid crystal material of the liquid crystal layer LC is dropped inside the seal portion SE (liquid crystal drop ST7). Two mother substrates are pasted together, and the seal part SE is cured (substrate bonding ST8). The method of injecting the liquid crystal layer LC is not limited to the steps ST7 and ST8 (one drop fill method). Alternatively, the first and second substrates SUB1 and SUB2 may be bonded first, and the liquid crystal layer LC may be sealed later.

  Perform trimming before cutting individual panels. The fracture surface of the glass substrate is more susceptible to the irregular reflection of the laser light than the smooth main surface. Since the polyimide substrates 10 and 20 may remain in intimate contact with the fractured surface of the glass substrate during laser lift-off described later, the polyimide substrates 10 and 20 are cut in advance slightly inside the fractured surface of the glass substrate. The end faces 10C and 20C described above are formed (trimming ST9). The mother substrate including the first and second substrates SUB1 and SUB2 together with the glass substrate is cut and divided into a plurality of panels (Cell cut ST10). The glass substrate and a part of the second substrate SUB2 are cut away to form the mounting region 3 (drive region formation ST11).

  In the panel after the process of ST9 to ST11, the above-described exposed areas 10Ax and 20Ax are exposed to the outside. This panel is placed in a high temperature and high humidity test tank, and moisture is absorbed from the exposed areas 10Ax and 20Ax to the polyimide substrates 10 and 20. (Humidification ST12). The flexibility of the display panel PNL differs between the area overlapping the hard seal part SE in plan view and the area inside the seal part SE, that is, the area overlapping the liquid crystal layer LC in plan view.

  In the case of laser lift-off, which will be described later, when the portion where the adhesion strength is reduced reaches the inside of the seal portion SE, the glass substrate is easily peeled off. The humidity of the outer surfaces 10B and 20B of the polyimide substrates 10 and 20 is preferably, for example, 50% RH or more slightly inside the seal portion SE.

  In order to make the polyimide base materials 10 and 20 absorb moisture, for example, a panel is installed in a test tank of the unsaturated pressure cooker test in accordance with JIS C 60068-2-66: 2001 (IEC 60068-2-66: 1994). The moisture may be absorbed for about 96 hours under the conditions of humidity 85% RH and temperature 110.degree.

  The external drive circuit 4 is mounted on the panel taken out from the inside of the test tank (external drive circuit mounting ST13). When an anisotropic conductive film is sandwiched between the external drive circuit 4 and the first substrate SUB1 and simultaneously pressurized and heated, a part of the anisotropic conductive film is melted to form the external drive circuit 4 and the first substrate Electrically and mechanically connected to SUB1. A resin material is applied and cured to form a resin film that protects the mounting area 3 (resin film formation ST14).

  The glass substrate is peeled off from the polyimide substrate 10 of the panel (first glass substrate peeling ST15). When the outer surface 10B of the polyimide substrate 10 is irradiated with laser light through the translucent glass substrate, the polyimide substrate 10 absorbs the laser light and is slightly decomposed. A void is generated at the interface between the polyimide substrate 10 and the glass substrate, and the glass substrate is peeled off from the polyimide substrate 10 (laser lift-off).

  At this time, the polyimide substrate 10 irradiated with the laser light absorbs moisture through the process of ST12. The polyimide base material 10 swells when it absorbs moisture, and it becomes energetically stable when it is separated from the glass substrate. As an example, if the moisture expansion coefficient (CHE) of the polyimide substrates 10 and 20 is 50 ppm /% RH or more, the glass substrates can be easily peeled off by the swelling of the polyimide substrates 10 and 20.

  Further, when the moisture which has entered the interface between the polyimide substrate 10 and the glass substrate is irradiated with the laser light, it becomes water vapor and lifts the polyimide substrate 10. In addition, when moisture intrudes into the interface between the polyimide substrate 10 and the glass substrate, the hydrogen bond between the polyimide substrate 10 and the glass substrate is inhibited to reduce the adhesion. Therefore, the energy of the laser beam can be suppressed and the glass substrate can be peeled off.

  The first polarizing plate PL1 is attached to the outer surface 10B of the polyimide substrate 10 (first polarizing plate attachment ST16). The first polarizing plate PL1 imparts rigidity to the first substrate SUB1. The glass substrate is peeled off from the polyimide substrate 20 in the same manner as the step ST15 (second glass substrate peeling ST17). Since the polyimide substrate 20 absorbs moisture, the energy of the laser beam can be suppressed and the glass substrate can be peeled off.

  The second polarizing plate PL2 is attached to the outer surface 20B of the polyimide substrate 20 (second polarizing plate attachment ST18). The obtained panel is put into an autoclave for the purpose of disappearance of micro air bubbles and improvement of peeling strength. An example of autoclave conditions is temperature: 50 ° C., pressure: 0.5 MPa, time: 30 minutes. After autoclaving, the back light BL is assembled to the panel to complete the display device DSP. Unnecessary parts may be cut off from the mounting area 3 or the like in the middle process. In that case, the exposed areas 10Ax and 20Ax become discontinuous in the finished display device DSP.

  The display device DSP of the present embodiment configured as described above has exposed regions 10Ax and 20Ax in which the inner surfaces 10A and 20A of the polyimide substrates 10 and 20 are not covered by the passivation film. If the polyimide substrates 10 and 20 in which the exposed regions 10Ax and 20Ax are formed are placed in a high temperature and high humidity test tank, the polyimide substrates 10 and 20 can absorb moisture.

  When the glass substrate is peeled by irradiating the laser light, if the polyimide substrates 10 and 20 absorb moisture, the polyimide substrates 10 and 20 extend and the glass substrates are easily peeled off. Since it is possible to peel off the glass substrate by suppressing the energy of the laser beam, the polyimide substrates 10 and 20 burn and wrinkles are generated, or the end surfaces 10C and 20C of the polyimide substrates 10 and 20 are cracked in advance. It can prevent.

  Next, with reference to FIGS. 5 to 10, display devices DSP according to second to fourth embodiments and their modifications will be described. The components having the same or similar functions as the components of the first embodiment are denoted by the same reference numerals, and the description of the corresponding first embodiment is referred to, and the description thereof is omitted here. Further, the other configuration is the same as that of the first embodiment.

Second Embodiment
FIG. 5 is a cross-sectional view schematically showing the configuration of the display device DSP of the second embodiment in a state of being separated from the mother substrate, and FIG. 6 is a cross-sectional view showing a modification thereof. The second embodiment and its modification are different from the first embodiment in that the polyimide substrates 10 and 20 have a multilayer structure. The polyimide substrate 20 has substantially the same shape and function as the polyimide substrate 10. Therefore, representatively, the polyimide substrate 10 will be described in detail, and the overlapping description of the polyimide substrate 20 will be omitted.

  In the example shown in FIG. 5, the polyimide base material 10 contains the 1st and 2nd polyimide base materials 110 and 120 which are two layers of polyimide base materials which are different. The second polyimide substrate 120 is laminated on the first polyimide substrate 110 and is located closer to the liquid crystal layer LC than the first polyimide substrate 110.

  The outer first polyimide base 110 is formed of a polyimide resin having a humidity expansion coefficient larger than that of the inner second polyimide base 120. The humidity expansion coefficient is, for example, about 50 ppm /% RH or more for the first polyimide substrate 110 and about 10 to 20 ppm /% RH for the second polyimide substrate 120.

  Between the first and second polyimide substrates 110 and 120, a barrier layer 200 that is less permeable to moisture than the first or second polyimide substrates 110 and 120 may be formed. The barrier layer 200 is an inorganic film similar to the first insulating layer 11 and the underlayer 21. In addition, the organic membrane with low water vapor permeability may be used. The first polyimide substrate 110 has an outer surface 110B constituting the outer surface 10B of the polyimide substrate 10, and an inner surface 110A opposite to the outer surface 110B.

  The inner surface 110A of the first polyimide substrate 110 includes the barrier layer 200 and an exposed region 110Ax exposed from the second polyimide substrate 120. The inner surface 10A of the polyimide substrate 10 facing the liquid crystal layer LC includes the inner surface 120A of the second polyimide substrate 120 and the exposed region 110Ax of the first polyimide substrate 110.

  Of the inner surface 10A of the polyimide substrate 10, the inner surface 120 formed by the second polyimide substrate 120 is covered with the aforementioned first insulating layer 11 which is a passivation film. On the other hand, the exposed region 110 </ b> Ax formed by the first polyimide base 110 is not covered by the first insulating layer 11 and is exposed to the outside.

  The polyimide substrate 10 may have three or more layers. In the example shown in FIG. 6, the polyimide base 10 is formed in a triple structure including the first to third polyimide bases 110, 120 and 130. The third polyimide base 130 is located closer to the liquid crystal layer LC than the second polyimide base 120.

  The inner surface 130 A of the third polyimide base 130 constituting the inner surface 10 A of the polyimide base 10 is covered with the first insulating layer 11. Of the inner surface 10A, the exposed region 110Ax of the first polyimide substrate 110 is exposed from the first insulating layer 11, the barrier layer 200, and the second and third polyimide substrates 120 and 130.

  When the outer surface 10B of the polyimide substrate 10 absorbs moisture, the energy of the laser beam can be suppressed and the glass substrate can be peeled off. I want to introduce water to the outer surface 10B. On the other hand, when the alignment films 16 and 25 in contact with the liquid crystal layer LC absorb moisture, flicker may occur during low frequency driving. I do not want to introduce water into the inner surface 10A.

  In the second embodiment, the polyimide substrate 10 has a multilayer structure, and the exposed region 110Ax is formed on the first polyimide substrate 110 located in the outermost layer. Therefore, the moisture absorbed in the process of ST12 can be biased to the outside of the polyimide substrate 10. Between the first polyimide substrate 110 and the other polyimide substrates 120 and 130, a barrier layer 200 which hardly transmits moisture is formed. The moisture transfer from the first polyimide substrate 110 to the other polyimide substrates 120 and 130 can be blocked by the barrier layer 200.

  In the second embodiment, since the polyimide substrate 10 has a multilayer structure, the humidity expansion coefficient can be optimized according to the site. The outer first polyimide substrate 110 having a humidity expansion coefficient larger than that of the inner side is greatly extended when it absorbs moisture, and is easily peeled off from the glass substrate. The inner second or third polyimide substrates 120, 130 having a humidity expansion coefficient smaller than that of the outer side are excellent in dimensional accuracy.

Third Embodiment
FIG. 7 is a cross-sectional view schematically showing the configuration of the display device DSP of the third embodiment in a state of being separated from the mother substrate. The third embodiment is different from the first embodiment in that the humidity expansion coefficient of the polyimide substrate 10 is different between the outer surface 10B and the inner surface 10A. The humidity expansion coefficient of the polyimide substrate 10 is, for example, 50 ppm /% RH or more at the outer surface 10 B and, for example, less than 20 ppm /% RH at the inner surface 10 A.

  The humidity expansion coefficient of the polyimide substrate 10 may increase gradually from the inner surface 10A toward the outer surface 10B, or may increase rapidly only in the vicinity of the outer surface 10B. According to the third embodiment, since the outer surface 10B is easily expanded, it is easily peeled off from the glass substrate. Since the inner surface 10A is difficult to expand, the dimensional accuracy is excellent.

Fourth Embodiment
The display device DSP of the fourth embodiment is an organic EL display device, and includes a flexible display panel PNL and an external drive circuit that controls the operation of the display panel PNL. FIG. 8 is a cross-sectional view showing the structure of the display panel PNL in the display area DA.

  The display panel PNL includes a polyimide substrate 30, first to fourth insulating layers 31, 32, 33, 34, a semiconductor layer SC, a gate electrode WG, a source electrode WS, a drain electrode WD, a pixel electrode PE, a common electrode CE, an organic The light emitting layers ORG1, ORG2, ORG3, the reflective layer 35, the ribs 36, the sealing material 37, and the like are provided.

  The polyimide substrate 30 is formed of a flexible, translucent, and insulating polyimide resin, and has an inner surface 30A and an outer surface 30B opposite to the inner surface 30A. The first insulating layer 31 covers the inner surface 30 A of the polyimide substrate 30. The first insulating layer 31 is an example of a passivation film, and is formed of the same inorganic material as the first insulating layer 11 and the base layer 21 described above.

  The semiconductor layer SC is formed on the first insulating layer 31. The second insulating layer 32 covers the first insulating layer 31 and the semiconductor layer SC. The gate electrode WG is formed on the second insulating layer 32. The third insulating layer 33 covers the second insulating layer 32 and the gate electrode WG. The source electrode WS and the drain electrode WD are formed on the third insulating layer 33.

  The source electrode WS and the drain electrode WD are electrically connected to the semiconductor layer SC through contact holes penetrating the second and third insulating layers 32 and 33. The fourth insulating layer 34 is an organic insulating layer that planarizes the unevenness of the thin film transistor, and covers the third insulating layer 33, the source electrode WS, and the drain electrode WD.

  The reflective layer 35 is a metal material having a high light reflectance, such as aluminum or silver, and is formed on the fourth insulating layer 34. The pixel electrode PE is formed on the reflective layer 35 and connected to the drain electrode WD. The organic light emitting layers ORG1, ORG2 and ORG3 are formed on the pixel electrode PE and are partitioned by the ribs 36.

  For example, the organic light emitting layer ORG1 is formed of a material that emits light of red wavelength when current flows, the organic light emitting layer ORG2 is formed of a material that emits light of green wavelength when current flows, and the organic light emitting layer ORG3 is a current And is formed by a material that emits blue wavelength light. The organic light emitting layers ORG1, ORG2 and ORG3 are examples of an optical layer (electro-optical layer) which is electrically driven to form an image.

  The common electrode CE is formed on the organic light emitting layers ORG1, ORG2, ORG3 and the rib 36. One of the pixel electrode PE and the common electrode CE is an anode, and the other is a cathode. The sealing material 37 is formed of, for example, a laminate of an organic film and an inorganic film, and covers the common electrode CE.

  The display panel PNL may further include the protective member 5 attached to the sealing material 37, and the support base 6 attached to the outer surface 30B of the polyimide base 30. The protective member 5 is, for example, a cover glass for protecting the sealing material 37, a polarizing plate or a retardation plate which suppresses the influence of external light. The support substrate 6 is, for example, a polyethylene terephthalate (PET) film that suppresses the deformation of the display panel PNL.

  FIG. 9 is a cross-sectional view schematically showing the configuration of the display device of the fourth embodiment in a state of being separated from the mother substrate. The inner surface 30A of the polyimide substrate 30 according to the fourth embodiment includes the exposed region 30Ax exposed from the first insulating layer 31 as in the first embodiment. The polyimide base material 30 may have a multilayer structure as in the second embodiment, and the moisture expansion coefficient is different between the outer surface 30B and the inner surface 30A as in the third embodiment. It is also good.

  FIG. 10 is a flow chart showing an example of a method of manufacturing the display device DSP of the fourth embodiment. A manufacturing method for manufacturing the display device DSP of the fourth embodiment will be described with reference to FIG. In the method of manufacturing the display device DSP, first, the material of the polyimide substrate 30 is applied to the upper surface of the glass substrate, and the applied material is cured to form the polyimide substrate 30 (polyimide substrate formation st1). A first insulating layer (passivation film) 31 is formed on the polyimide substrate 30.

  Second to fourth insulating layers 32, 33, 34, the semiconductor layer SC, the gate electrode WG, the source electrode WS, the drain electrode WD, the pixel electrode PE, the common electrode CE, the organic light emitting layer ORG1, on the first insulating layer 31. An organic EL layer including ORG2 and ORG3, the reflective layer 35, the rib 36 and the like is formed (organic EL layer formation st2).

  The sealing material 37 is formed on the organic EL layer (sealing material formation st3). The upper surface of the sealing material 37 is covered with a curing film (curing film sticking st4). The curing film protects the sealing material 37 in the manufacturing process and imparts rigidity to the polyimide substrate 30 so as not to deform.

  The panel is singulated with the glass substrate (cell cut st5). A laser beam is irradiated slightly inside the broken surface of the glass substrate to form an end face 30C (trimming st6). In the panel after the processes of st5 and st6, the above-described exposed area 30Ax is exposed to the outside. This panel is put into a high temperature and high humidity test tank, and moisture is absorbed from the exposed area 30Ax to the polyimide substrate 30. (Humidification st7).

  In addition, it is also possible to perform trimming st6 before cell cut st5. In that case, in a state where individual panels are formed on the mother substrate, laser light is irradiated slightly inside of the panel outline to form the end face 30C (trimming st 6), and then the panels are separated (cell Cut st5).

  The glass substrate is peeled off by irradiating the absorbed polyimide substrate 30 with laser light (glass substrate peeling st8). The curing film is peeled off from the panel after the process of st8, the protective member 5 and the support base 6 are adhered, and an external drive circuit is mounted, whereby the display device DSP shown in FIG. 8 is completed. According to the fourth embodiment, as in the first embodiment, by causing the polyimide substrate 30 to absorb moisture in advance, the energy of laser light can be suppressed and the glass substrate can be peeled off.

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof. The configurations disclosed in each embodiment can be combined as appropriate.

  In each embodiment, although the liquid crystal display device provided with a liquid crystal layer as an electro-optical layer and the organic EL display device provided with an organic light emitting layer as an electro-optical layer are disclosed, the electro-optical layer is not particularly limited. The electro-optical layer may be an electrophoretic element, a micro electro mechanical system (MEMS), or an electrochromic element.

  10, 20, 30 ... polyimide base material, 10A, 20A, 30A ... inner surface, 10Ax, 20Ax, 30Ax, 110Ax ... exposed region, 10B, 20B, 30B ... outer surface, 11 ... first insulating layer (an example of passivation film), 11E: outer edge of the first insulating layer (an example of the boundary) 21: base layer (an example of the passivation film) 21 E: outer edge of the base layer (an example of the boundary) 110: first polyimide base material 120: second polyimide Base material, 200: barrier layer (an example of inorganic film), DSP: display device, LC: liquid crystal layer (an example of optical layer), ORG1, ORG2, ORG3: organic light emitting layer (an example of optical layer).

Claims (9)

An optical layer,
A polyimide substrate having an inner surface facing the optical layer and an outer surface opposite to the inner surface;
And a passivation film formed between the optical layer and the polyimide substrate.
The display device, wherein the inner surface has an exposed region in which the polyimide substrate is exposed from the boundary of the region where the passivation film is formed toward the end of the polyimide substrate.   The display device according to claim 1, wherein the polyimide substrate is formed of a polyimide resin having a humidity expansion coefficient of 50 ppm /% RH or more.   The display device according to claim 1, wherein the outer surface of the polyimide substrate has a humidity expansion coefficient larger than that of the inner surface. The polyimide substrate includes a first polyimide substrate constituting the outer surface, and a second polyimide substrate laminated on the first polyimide substrate from the side opposite to the outer surface,
The display device according to claim 1, wherein the first polyimide substrate includes the exposed region exposed to the outside from the passivation film and the second polyimide substrate.   The display device according to claim 4, wherein the first polyimide base has a humidity expansion coefficient larger than that of the second polyimide base.   The display device according to claim 4, wherein the first polyimide substrate is formed of a polyimide resin having a humidity expansion coefficient of 50 ppm /% RH or more.   The display device according to any one of claims 4 to 6, wherein an inorganic film is formed between the first polyimide substrate and the second polyimide substrate.   The display device according to any one of claims 1 to 7, wherein the polyimide substrate is formed of a porous polyimide resin.   The display device according to any one of claims 1 to 8, wherein the passivation film has a humidity expansion coefficient smaller than that of the polyimide substrate.

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