JP7158914B2 - Display device - Google Patents

Description

The present invention relates to a display device and, for example, to a technique effectively applied to a bendable liquid crystal display device.

As a mode of the display device, a bendable display device is under consideration (see Japanese Patent Application Laid-Open No. 2017-126061 (Patent Document 1)).

JP 2017-126061 A

The inventor of the present application is developing a technology for a display device that can be folded. Among bendable display devices, it has been found that liquid crystal display devices have the following problems. In the case of a liquid crystal display device, an alignment film is provided in contact with the liquid crystal layer for the purpose of aligning the liquid crystal that controls the transmission of light. When there is an alignment film in the bendable region, part of the alignment film may be partially peeled off due to the force generated when it is bent. If a part of the peeled alignment film is present in the liquid crystal layer, the peeled part disturbs the alignment of the liquid crystal and causes deterioration of the display quality.

An object of the present invention is to provide a technique for improving performance of a display device.

A display device which is one embodiment of the present invention includes a flexible first substrate having a first region and a second region on its surface, a liquid crystal layer, and a photodecomposable alignment substrate in contact with the liquid crystal layer. a membrane; The first substrate is bendable in the second region, and the alignment film includes a first film in contact with the liquid crystal layer and containing a photodegradable material. The thickness of the first film in the second region is less than the thickness of the first film in the first region.

According to another aspect of the present invention, there is provided a display device comprising: a flexible first substrate having a first region and a second region on its surface; a liquid crystal layer; an alignment film in contact with the liquid crystal layer; A first transistor on a substrate and a first organic film between the first substrate and the alignment film covering the first transistor. The first substrate is bendable in the second region, and the thickness of the first organic film in the second region is thinner than the thickness of the first organic film in the first region.

A display device, which is another aspect of the present invention, includes a flexible first substrate having a first region and a second region on its surface, a liquid crystal layer, and a photodegradable liquid crystal layer in contact with the liquid crystal layer. an alignment film; The first substrate is bendable in the second area, and the alignment layer includes a first alignment layer in the first area and a second alignment layer in the second area. In plan view, a first member for separating the first alignment film and the second alignment film is arranged between the first alignment film and the second alignment film.

1 is a plan view showing an example of a display device according to an embodiment; FIG. 2 is a circuit block diagram showing a configuration example of a circuit included in each of a plurality of pixels shown in FIG. 1; FIG. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1; 2 is an enlarged cross-sectional view of a portion of the display area of FIG. 1; FIG. FIG. 4 is an explanatory diagram showing an example of the relationship between the alignment axis of an alignment film and the polarization axis of ultraviolet rays with which the alignment film is irradiated; 5 is an enlarged cross-sectional view showing a configuration example of an alignment film shown in FIG. 4; FIG. FIG. 7 is an enlarged cross-sectional view of an alignment film of a display device that is a modified example of FIG. 6; 2 is a perspective view of a display device that is a modified example of FIG. 1; FIG. FIG. 9 is a plan view when the display device shown in FIG. 8 is unfolded; FIG. 10 is an enlarged cross-sectional view taken along line AA of FIG. 9; FIG. 11 is an enlarged cross-sectional view of a display device that is a modified example of FIG. 10; FIG. 12 is an enlarged cross-sectional view of a display device that is a modified example of FIG. 11; FIG. 4 is an enlarged cross-sectional view showing an enlarged periphery of a boundary between alignment films separated from each other in a display device that is a modification of FIG. 3 ; 14 is an enlarged plan view of the portion shown in FIG. 13 as viewed from the display surface side; FIG. FIG. 14 is an enlarged cross-sectional view of a display device that is a modified example of FIG. 13; FIG. 15 is an enlarged plan view of a display device that is a modified example of FIG. 14; FIG. 17 is an enlarged cross-sectional view taken along line AA of FIG. 16; 2 is an enlarged plan view of a display device that is a modified example of FIG. 1; FIG. FIG. 19 is an enlarged cross-sectional view taken along line AA of FIG. 18; FIG. 19 is an enlarged plan view of a display device that is a modified example of FIG. 18;

Each embodiment of the present invention will be described below with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art will naturally include within the scope of the present invention any appropriate modifications that can be easily conceived while maintaining the gist of the invention. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is only an example, and the interpretation of the present invention is not intended. It is not limited. In addition, in this specification and each figure, the same or related reference numerals may be given to elements similar to those described above with respect to the previous figures, and detailed description thereof may be omitted as appropriate.

(Embodiment 1)
<Configuration of display device>
First, the configuration of the display device will be described. FIG. 1 is a plan view showing an example of the display device of this embodiment. In FIG. 1, the boundary between the display area DA and the peripheral area PFR in plan view is indicated by a chain double-dashed line. Further, in FIG. 1, part of the circuit blocks and wiring of the circuit included in the display device DSP2 are schematically shown by solid lines. FIG. 2 is a circuit block diagram showing a configuration example of a circuit included in each of the plurality of pixels shown in FIG. 3 is a cross-sectional view taken along line AA of FIG. 1. FIG. Although FIG. 3 is a cross-sectional view, hatching is omitted except for the liquid crystal layer LQ and the sealing material BND for ease of viewing. In addition to the substrate 10, the substrate 20, and the liquid crystal layer LQ shown in FIG. It has various parts. In FIG. 3, illustration of these components is omitted. 4 is an enlarged cross-sectional view of a portion of the display area in FIG.

The substrate SUB1 shown in FIG. 3 includes, in addition to the substrate 10 shown in FIG. 4, a plurality of insulating layers, a transistor Tr1, patterns such as wiring, and an alignment film AF1. Further, the substrate SUB2 shown in FIG. 3 includes, in addition to the substrate 20 shown in FIG. 4, a color filter CF, a light shielding film BM, an insulating film OC1, and an alignment film AL2. In FIG. 3, illustration of these members included in the substrate SUB1 and the substrate SUB2 is omitted.

As shown in FIG. 1, the display device DSP1 of this embodiment has a display area DA in which an image is formed according to an input signal supplied from the outside. The display area DA is an effective area for displaying an image visually recognized by the viewer. In this embodiment, the display area DA has an area (first area) DA1, an area (second area) DA2, and an area (third area) DA3. Areas DA2 and DA3 of the display area DA are bendable areas. In other words, the area DA2 and the area DA3 have a structure that is supposed to be folded during use or carrying. Of the display area DA, the area DA1 is an area that is not supposed to be folded (in other words, it is not foldable). The above-described structure that is supposed to be bent means that in addition to having a structure that is simply physically bendable, measures are taken to deal with the problems caused by bending the display area DA. Therefore, for example, the area DA1 may have a physically bendable structure. The details of the problems caused by bending the display area DA will be described later.

The display device DSP1 also has a peripheral area PFR around the display area DA in a plan view. The peripheral area PFR has a sealing material BND surrounding the periphery of the display area DA. Further, in the peripheral area PFR, there are a plurality of wirings connected to a plurality of transistors arranged in the display area DA.

A plurality of pixels PX are arranged in the display area DA. The plurality of pixels PX are arranged in a matrix along the X direction and the Y direction intersecting the X direction. Each of the plurality of pixels PX has a transistor Tr1 (see FIG. 2) functioning as a pixel selection switch and a pixel electrode PE (see FIG. 2) connected to the transistor Tr1. The display area DA also has a plurality of scanning lines (gate lines) GL extending along the X direction and a plurality of video signal lines (source lines) SL extending along the Y direction. In the example shown in FIG. 1, the multiple scanning lines GL are arranged in the X direction, and the multiple video signal lines SL are arranged in the Y direction. In addition, there is a common electrode CE in the display area DA. The common electrode CE is an electrode that supplies a common potential to be applied to each of the pixels PX, and overlaps the plurality of pixels PX, for example.

Each of the plurality of video signal lines SL is connected to the pixel electrode PE via the transistor Tr1, as shown in FIG. Specifically, the video signal line SL is connected to the source electrode SE of the transistor Tr1, and the pixel electrode PE is connected to the drain electrode DE of the transistor Tr1. When the transistor Tr1 is turned on, the pixel electrode PE is supplied with the video signal Spic from the video signal line SL. The video signal Spic is supplied from the signal line drive circuit SD. The video signal lines SL in the display area DA are electrically connected to the signal line drive circuit SD via connection wirings (also called lead wirings). The signal line drive circuit SD supplies the video signal Spic to the pixel electrode PE provided in each of the plurality of pixels PX via the video signal line SL. The signal line drive circuit SD is arranged outside the display area DA shown in FIG. 1 (for example, the peripheral area PFR, or the wiring substrate and semiconductor components connected to the substrate SUB1 in the peripheral area PFR).

Each of the plurality of scanning lines GL drives a transistor Tr1 as shown in FIG. Specifically, a portion of the scanning line GL constitutes the gate electrode GE of the transistor Tr1. Each of the plurality of scanning lines GL is drawn out to the peripheral area PFR outside the display area DA and connected to the scanning line driving circuit (gate driving circuit) GD shown in FIG. The scanning line driving circuit GD is a scanning signal output circuit that outputs scanning signals Gsi input to the plurality of scanning lines GL. Scanning line drive circuit GD is arranged in peripheral region PFR shown in FIG. The transistor Tr1 is a thin film transistor (TFT) that functions as a selection switch that selects the pixel PX. Also, the scanning line GL includes the gate electrode GE of the transistor Tr1.

The display device DSP1 has a substrate 10 . The display device DSP1 also includes a substrate 20 facing the substrate 10 with the liquid crystal layer LQ interposed therebetween. The substrate 10 has a front surface (main surface, front surface) 10f facing the liquid crystal layer LQ, and a rear surface (main surface, rear surface) 10b opposite to the front surface 10f. The substrate 20 also has a rear surface (main surface, rear surface) 20b facing the liquid crystal layer LQ and a front surface (main surface, front surface) 20f opposite to the rear surface 20b. The substrate 10 has an area (first area) DA1, an area (second area) DA2, and an area (third area) DA3 on each of the front surface 10f and the rear surface 10b. The substrate 20 also has an area (first area) DA1, an area (second area) DA2, and an area (third area) DA3 on each of the front surface 20f and the rear surface 20b.

Each of substrate 10 and substrate 20 is bendable in area DA2 and area DA3. Therefore, each of substrate 10 and substrate 20 is flexible at least in areas DA2 and DA3. In this embodiment, substrate 10 and substrate 20 are flexible in areas DA1, DA2, and DA3. In order to impart flexibility to the substrates 10 and 20, the substrates 10 and 20 are made of, for example, a resin material (organic material) containing a polymer such as polyimide, polyamide, polycarbonate, or polyester.

Circuit components including the transistor Tr1 forming the pixel PX shown in FIG. 2 are formed on the substrate 10 as shown in FIG. The display device DSP1 has an insulating film 11 on the front surface 10f of the substrate 10 in the display area DA. The insulating film 11 is a base layer for various circuits including TFTs, and is made of an inorganic insulating material such as silicon nitride (SiN) or silicon oxide (SiO).

A transistor Tr1, which is a TFT, is formed on the insulating film 11, which is a base layer. FIG. 4 exemplarily shows one transistor Tr1. The transistor Tr1 is a thin film transistor (TFT). The transistor Tr1 includes a semiconductor region (semiconductor layer) SCR forming a channel region, a source region, and a drain region. The semiconductor region SCR is made of polysilicon, for example, and formed on the insulating film 11 . A conductor pattern CDP connected to the source electrode SE or the drain electrode DE of the transistor Tr1 is formed in the source region and the drain region of the semiconductor region SCR. The conductor pattern CDP is formed by sputtering, for example.

The semiconductor region SCR is covered with an insulating film 12 which is a gate insulating film. The insulating film 12 is made of silicon oxide, for example, and is deposited on the semiconductor region SCR and the conductor pattern CDP by chemical vapor deposition (CVD), for example. A gate electrode GE is formed on the insulating film 12 . The gate electrode GE is formed at a position overlapping with the channel region of the semiconductor region SCR. In other words, the channel region of the semiconductor region SCR faces each other with the insulating film 12 as the gate insulating film interposed therebetween. The gate electrode GE is formed by patterning a metal film formed by sputtering or the like. Although not shown, a plurality of scanning lines GL shown in FIG. 1 are formed in the same layer as the gate electrode GE.

The gate electrode GE and the insulating film 12 are covered with the insulating film 13 . The insulating film 13 is made of, for example, silicon nitride, silicon oxide, or a laminated film thereof. The insulating film 13 is formed by, for example, the CVD method. A source electrode SE and a drain electrode DE, which are metal films, are formed on the insulating film 13 . A contact hole is formed in the insulating films 12 and 13 to pass through the insulating films 12 and 13 in the thickness direction, and the source electrode SE is connected to the conductor pattern CDP on the source region through the contact hole. Also, the drain electrode DE is connected to the conductor pattern CDP on the drain region through a contact hole. The source electrode SE and the drain electrode DE are formed by, for example, sputtering. A plurality of video signal lines SL shown in FIG. 1 are formed in the same layer as the source electrode SE and the drain electrode.

The source electrode SE, the drain electrode DE, and the insulating film 13 are covered with the insulating film 14 . The insulating film 14 is made of, for example, silicon nitride, silicon oxide, or a laminated film thereof. The insulating film 14 is formed by, for example, the CVD method.

An organic film (flattening film, organic insulating film) 15 is formed on the insulating film 14 . The organic film 15 is made of an organic material such as acrylic resin. The thickness of the organic film 15 is thicker than the thickness of each of the other insulating films 11, 12, 13, and . Further, the organic film 15 covers the transistor Tr1.

A common electrode CE is formed on the organic layer 15 . During a display period during which the display device DSP1 displays an image, the common electrode CE is supplied with a common driving potential corresponding to the plurality of pixels PX (see FIG. 1). A common drive potential is supplied from a common electrode drive circuit CD shown in FIG. The common electrode CE is arranged over the entire display area DA. The common electrode CE is made of a transparent conductive material such as ITO (Indium tin oxide) or IZO (Indium Zinc Oxide). The common electrode CE is covered with an insulating film 16 . The insulating film 16 is made of, for example, silicon nitride, silicon oxide, or a laminated film thereof. The insulating film 16 is formed by, for example, the CVD method.

In the example shown in FIG. 4, the pixel electrode PE is formed on the insulating film 16. As shown in FIG. In the example shown in FIG. 4, the common electrode CE and the pixel electrode PE are formed in different layers. However, as a modification, a plurality of common electrodes CE and a plurality of pixel electrodes PE may be formed on the same surface (for example, on the organic film 15) and alternately arranged so as to be adjacent to each other. The pixel electrode PE is preferably made of a transparent conductive material such as ITO or IZO or a metal material. The pixel electrode PE is connected to the drain electrode DE through a contact hole formed through the insulating film 16 and the organic film 15 .

In the display period, when different potentials are supplied to the pixel electrode PE and the common electrode CE, electric lines of force are generated connecting the pixel electrode PE and the common electrode CE. The liquid crystal molecules in the liquid crystal layer LQ are rotated by the electric field generated at this time.

Also, each of the plurality of pixel electrodes PE is covered with the alignment film AL1. The alignment film AL1 is an insulating film having a function of aligning the initial alignment of the liquid crystal molecules contained in the liquid crystal layer LQ, and is made of polyimide resin, for example. The alignment film AL1 is between the substrate 10 and the liquid crystal layer LQ and is in contact with the liquid crystal layer. Also, the alignment film AL1 is in contact with the liquid crystal layer LQ. Details of the alignment film AL1 will be described later.

Further, the display device DSP1 has a light shielding film BM, a color filter CF, an insulating film OC1, and an alignment film AL2 between the back surface (main surface) 20b of the substrate 20 and the liquid crystal layer LQ.

The color filters CF are formed on the back surface 20 b side of the substrate 20 . As for the color filters CF, three color filters CF of red (R), green (G), and blue (B) are periodically arranged.

A light shielding film BM is arranged at the boundary between the color filters CF of each color. The light shielding film BM is called a black matrix, and is made of, for example, black resin or low-reflectivity metal. The light shielding film BM is formed, for example, in a lattice shape in plan view.

Moreover, the insulating film OC1 shown in FIG. 4 covers the color filters CF. The insulating film OC1 functions as a protective film that prevents impurities from diffusing from the color filter to the liquid crystal layer. The insulating film OC1 is an organic insulating film made of, for example, an acrylic photosensitive resin. Further, an alignment film AL2 is arranged on the insulating film OC1. The alignment film AL2 is between the substrate 20 and the liquid crystal layer LQ and is in contact with the liquid crystal layer LQ. Each of the alignment film AL1 and the alignment film AL2 is a photo-alignment film which is aligned by irradiating polarized ultraviolet rays.

<Alignment film>
Next, the detailed structure of the alignment film shown in FIG. 4 will be described. FIG. 5 is an explanatory diagram showing an example of the relationship between the alignment axis of the alignment film and the polarization axis of the ultraviolet rays with which the alignment film is irradiated. The alignment film AL1 and the alignment film AL2 are films obtained by imidating polyamic acid or polyamic acid ester. The photo-alignment treatment for the alignment films AL1 and AL2 is performed by irradiating the alignment films AL1 and AL2 with polarized ultraviolet rays having a wavelength of about 250 nm, for example. Hereinafter, as an example of the alignment film AL1 and the alignment film AL2, the alignment film AL1 formed between the substrate 10 and the liquid crystal layer LQ shown in FIG. 4 will be described as a typical example. The same applies to the alignment film AL2 formed between. In each embodiment described below, the technique described for the alignment film AL1 can be applied to the alignment film AL2.

In the example shown in FIG. 5, the alignment film AL1 has an X-direction alignment axis ALP that intersects with the Y-direction by irradiating the alignment film AL1 with ultraviolet rays having a Y-direction polarization axis UVP. The alignment film AL1 before the photo-alignment treatment comprises a polyimide PI1 whose main chain directions are randomly arranged in various directions on the XY plane. In the photo-alignment treatment, when the alignment film AL1 is irradiated with ultraviolet rays having a polarization axis UVP, the polyimide PI1 in which the main chain direction is arranged parallel to the polarization axis UVP of the ultraviolet rays absorbs a large amount of polarized ultraviolet rays, As schematically shown in FIG. 5, the cyclobutane ring contained in the polyimide PI1 is cleaved to form a composition PI2 in which the polyimide PI1 is split. On the other hand, the polyimide PI1, which is arranged so that the main chain direction is orthogonal to the polarization axis UVP of ultraviolet rays, hardly absorbs ultraviolet rays and is not split.

The composition PI2 in which the polyimide PI1 is divided does not contribute to the alignment of the liquid crystal molecules, and the undivided polyimide PI1 contributes to the alignment of the liquid crystal molecules. Therefore, by irradiating ultraviolet rays having a polarization axis UVP, the polyimide PI1 having a main chain in a direction parallel to the polarization axis UVP is selectively cleaved, resulting in a direction orthogonal to the polarization axis UVP. An alignment film AL1 having an alignment axis ALP is obtained.

When the alignment film AL1 is used in an unfolded state, no particular problem occurs even if the composition PI2 is contained in the alignment film AL1. However, as in the present embodiment, when a part of the display area DA is used by being bent, it has been found that a problem arises due to the weak mechanical strength of the alignment film AL1. That is, by folding the alignment film AL1 containing the composition PI2, a part of the alignment film AL1 is peeled off from the main body at the folded portion. When a portion of the alignment film AL1 is peeled off, the orientation of the liquid crystal molecules in the liquid crystal layer LQ shown in FIG. 4 is hindered by the peeled debris. As a result, if the location where the orientation of the liquid crystal molecules is disturbed is visually recognized as a minute bright spot, it causes deterioration in display quality.

Therefore, the inventors of the present application have studied a technique capable of suppressing peeling of the alignment film AL1 in the bendable region. More specifically, a method for making the alignment film AL1 arranged in the area DA2 and the area DA3 shown in FIG. 1 stronger in mechanical strength than the alignment film AL1 arranged in the area DA1. Study was carried out. FIG. 6 is an enlarged cross-sectional view showing a structural example of the alignment film shown in FIG. In FIG. 6, the boundaries of each film are clearly shown in order to clearly show that the alignment film AL1 has a structure in which films with different component ratios are laminated. be. Moreover, there may be a film in which both film materials are mixed between the two films.

As shown in FIG. 6, the alignment film AL1 of the present embodiment has a film (part) L1A in the region DA1 and a film (part) L1B between the film L1A and the substrate 10. As shown in FIG. Also, the alignment film AL1 has a film (portion) L2A in the area DA2 and a film (portion) L2B between the film L2A and the substrate 10 . The thickness of the film L2A of the alignment film AL1 included in the display device DSP1 is thinner than the thickness of the film L1A. Also, the thickness of the film L2B of the alignment film AL1 is thicker than the thickness of the film L1B. The thickness of the alignment film AL1 is substantially the same between the area DA1 and the area DA2. The thicknesses of the film L1A and the film L1B arranged in the region DA1 are approximately the same (half the thickness of the alignment film AL1). On the other hand, the thickness of the film L2A located in the area DA2 is thinner than the thickness of the film L2B. For example, in the example shown in FIG. 6, the thickness of film L2A is about 25% of the thickness of film L2B.

In the case of the display device DSP1, each of the films L1A and L2A of the alignment film AL1 contains a photodegradable material as a main component like the polyimide PI1 shown in FIG. Further, in the case of the display device DSP1, the film L2A and the film L2B are made of different materials. Similarly, the films L1A and L1B are made of different materials. In the example shown in FIG. 6, the material of the films L1A and L2A of the alignment film AL1 is polyimide PIA1 having a 1,3-dimethylcyclobutane skeleton, and the material of the films L1B and L2B is polyimide having a pyromellitic imide skeleton. PIB.

A polyimide PIA1 having a cyclobutane skeleton having a substituent represented by a 1,3-dimethylcyclobutane skeleton is compared with a polyimide having an unsubstituted cyclobutane skeleton, such as the polyimide PI1 shown in FIG. The cyclobutane ring is easily cleaved. In other words, the polyimide PIA1 has a higher decomposition sensitivity to ultraviolet rays than the polyimide PI1, so that the alignment characteristics can be easily controlled by the photo-alignment treatment. On the other hand, polyimide PIB having a pyromellimide imide skeleton does not have a cyclobutane ring in its main chain, so that it is difficult to split even when irradiated with ultraviolet light during photo-alignment treatment. In other words, the polyimide PIB shown in FIG. 6 has higher mechanical strength than the polyimide PIA1. As shown in FIG. 6, films L1B and L2B having high mechanical strength are arranged as underlying layers for films L1A and L2A having high orientation characteristics and low mechanical strength. Even if the L2A layer is folded, it is reinforced by the underlying layer. In addition, the substituent of the cyclobutane ring is not limited to a methyl group, and includes a fluorine atom, a chlorine atom, a bromine atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a vinyl group (-( CH ₂ )m-CH=CH ₂ , m=0, 1, 2) or an acetyl group (-(CH ₂ )m-C≡CH, m=0, 1, 2). In the following, an embodiment will be described using a 1,3-dimethylcyclobutane skeleton as an example of a cyclobutane skeleton having a substituent.

In the case of the display device DSP1, the thickness of the film L2A mainly composed of polyimide PIA1 with low mechanical strength is thinner than the thickness of the film L1A in the area DA2, which is assumed to be bent. Further, in the region DA2 of the alignment film AL1, the thickness of the film L2B that reinforces the strength of the film L2A is thicker than the thickness of the film L1B in the region DA1. In this case, the mechanical strength of the alignment film AL1, which is the combination of the film L2A and the film L2B, is sufficient in the area DA2. Therefore, even when the alignment film AL1 is bent in the area DA2, it is possible to suppress the peeling of a part of the alignment film AL1.

In the case of the present embodiment, the area DA3 is also a foldable area. Therefore, the area DA3 has a structure similar to that of the area DA2. That is, the alignment film AL1 has a film L3A overlapping with the region DA3 and a film L3B between the film L3A and the substrate 10 . The thickness of the film L3A of the alignment film AL1 included in the display device DSP1 is thinner than the thickness of the film L1A. Also, the thickness of the film L3B of the alignment film AL1 is thicker than the thickness of the film L1B. The thickness of the alignment film AL1 is substantially the same between the area DA1 and the area DA3. The thickness of film L3A located in area DA2 is less than the thickness of film L3B. For example, in the example shown in FIG. 6, the thickness of film L3A is about 25% of the thickness of film L3B. Therefore, even when the area DA3 is bent, it is possible to prevent the display quality of the area DA3 from deteriorating due to the peeled-off debris of the alignment film AL1.

In the example shown in FIG. 6, the material of each of film L1B, film L2B, and film L3B is polyimide PIB with a pyromellitic imide backbone. In the case of polyimide PIB having a pyromellimide imide skeleton, since it does not have a cyclobutane ring in its main chain, it is less likely to be split even if it is irradiated with ultraviolet rays during photo-alignment treatment. In other words, the polyimide PIB shown in FIG. 6 has higher mechanical strength than the polyimide PIA1. As shown in FIG. 6, the film L1B, the film L2B, and the film L3B having high mechanical strength are arranged as underlying layers for the film L1A, the film L2A, and the film L3A having high orientation characteristics, so that the film L2A Even if the film L3A is bent, it is reinforced by the base layer.

Note that the boundary between the films L1A and L1B, the boundary between the films L2A and L2B, and the boundary between the films L3A and L3B shown in FIG. 6 may not be clear. It is important that the main components of each film are different. Polyimide PIB and polyimide PIA1 (or polyimide PIA2) are mixed around the boundary of each film. Also, each of the films L1B, L2B, and L3B may contain polyimide PIA1 containing a cyclobutane ring.

A material that exhibits high decomposition sensitivity to ultraviolet rays and exhibits high orientation properties by photo-alignment treatment is, for example, polyimide PIA1 shown in FIG. polyimide. Therefore, in the film L1A shown in FIG. 6, it is preferable that the mass ratio of polyimide obtained by imidating polyamic acid or polyamic acid ester containing a cyclobutane ring is 80% or more. A structural example of polyamic acid or polyamic acid ester containing a cyclobutane ring is represented by the following chemical formula (1).

In chemical formula (1), each R ₁ is independently an alkyl group having 1 to 8 carbon atoms or a hydroxyl group (OH). R ₂ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a vinyl group (-(CH ₂ )m- CH═CH ₂ , m=0, 1, 2) or an acetyl group (—(CH ₂ )mC≡CH, m=0, 1, 2). Ar is an aromatic compound.

Moreover, the polyimide that is abundantly contained in each of the film L1B, the film L2B, and the film L3B shown in FIG. 6 is preferably a polyimide obtained by imidating polyamic acid that does not contain a cyclobutane ring. However, each of the films L1B, L2B, and L3B shown in FIG. 6 may contain polyimide obtained by imidating polyamic acid ester containing a cyclobutane ring. A structural example of a polyamic acid containing no cyclobutane ring is represented by the following chemical formula (2).

In chemical formula (2), each R1 is independently an alkyl group having 1 to 8 carbon atoms or a hydroxyl group (OH). R2 each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a vinyl group (-(CH ₂ )m-CH =CH ₂ , m = 0, 1, 2) or an acetyl group (-(CH ₂ )mC≡CH, m = 0, 1, 2). Ar is an aromatic compound.

The film L1A and the film L1B shown in FIG. 6 are mainly composed of different materials. and components constituting the membrane L2B can be separated in a self-aligned manner. That is, by using a highly polar diamine in the portion of Ar exemplified by the chemical formula (2), the surface energy of the polyamic acid increases, so that the pixel electrode PE (see FIG. 4), which is the base film of the alignment film AL1, and the Affinity for the organic film 15 (see FIG. 4) is increased. As a result, the polyamic acid containing no cyclobutane ring is attracted near the base film, and more polyamic acid represented by the chemical formula (2) is distributed in the film L1B than in the film L1A. When the imidization treatment is performed in this state, the film L1B contains a large amount of polyimide having no cyclobutane ring in its main chain, such as the polyimide PIB shown in FIG. On the other hand, like the polyimide PIA1 shown in FIG. 6, polyimide containing cyclobutane rings in its main chain is distributed in a large amount in the film L1A.

In the above, the distribution of polyimide contained in the films L1A and L1B shown in FIG. 6 has been described. The same is true for distribution.

As shown in FIG. 6, in the case of the display device DSP1, the material of the film L1A of the alignment film AL1 is the same as the material of the film L2A. However, as a modification, the material of the film L1A and the material of the film L2A of the alignment film AL1 may be different from each other. For example, in the case of the display device DSP2 shown in FIG. 7, the main component is polyimide PIA2 having an unsubstituted cyclobutane skeleton as the material of the film L2A. FIG. 7 is an enlarged cross-sectional view of an alignment film of a display device that is a modification of FIG.

In the case of the display device DSP2, the mechanical strength of the film L2A can be enhanced as compared with the display device DSP1, so the peeling of the alignment film AL2 can be further suppressed. On the other hand, from the viewpoint of improving the alignment characteristics of the region DA2, it is preferable that the material of the film L1A of the alignment film AL1 is the same as the material of the film L1B, as in the display device DSP1. The material of the film L1A of the alignment film AL1 is different from the material of the film L2A. For example, in the example shown in FIG. 7, the material of the film L1A of the alignment film AL1 is polyimide PIA1 having a 1,3-dimethylcyclobutane skeleton. The material of the film L2A of the alignment film AL1 is polyimide PIA2 having an unsubstituted cyclobutane skeleton.

In the polyimide PIA1 having a 1,3-dimethylcyclobutane skeleton, the cyclobutane ring is more likely to cleave when irradiated with ultraviolet light than in the polyimide PIA2 having an unsubstituted cyclobutane skeleton. In other words, the polyimide PIA1 has a higher decomposition sensitivity to ultraviolet rays than the polyimide PIA2, so that the alignment characteristics can be easily controlled by the photo-alignment treatment. On the other hand, since the polyimide PIA2 has a lower decomposition sensitivity to ultraviolet light than the polyimide PIA1, the film L2A of the alignment film AL1 has a higher mechanical strength when folded than the film L1A.

In the case of the display device DSP2, the film L2A made of the polyimide PIA2 is arranged in the region DA2 expected to be folded, and the film L1A made of the polyimide PIA1 is placed in the region DA1 not expected to be folded. In this case, since the film L1A of the alignment film AL1 arranged in the area DA1 has better alignment characteristics than the film L2A of the alignment film AL1 arranged in the area DA2, the display quality can be improved. On the other hand, since the film L2A having a high mechanical strength against bending is arranged in the region DA2, it is possible to suppress peeling of the alignment film AL1 due to bending. As a result, it is possible to prevent the display quality of the area DA2 from deteriorating due to the scraps from the peeling of the alignment film AL1.

Meanwhile, as shown in FIG. 7, in order to make the polyimide contained in the film L1A and the polyimide contained in the film L2A different from each other, a step of applying a raw material solution of polyimide to each region is performed. , it is preferable to apply a different material to each region. Also, as shown in FIG. 6, when the thickness of the film L1A and the thickness of the film L2A are to be different, it is preferable to apply the polyimide raw material having a different mixing ratio for each region in the step of applying the raw material liquid. . For example, in the manufacturing process of the display device DSP2, a polyimide PIA1 having a 1,3-dimethylcyclobutane skeleton is formed in the region DA1 by imidization treatment (for example, heat treatment at about 230° C. or dehydration/reduction treatment using a catalyst). A coating material containing polyamic acid that becomes polyamic acid that becomes polyimide PIB having a pyromellimide imide skeleton is applied by imidization treatment. Further, in the area DA2 and the area DA3, a coating containing a polyamic acid that becomes a polyimide PIA2 having an unsubstituted cyclobutane skeleton by imidation treatment and a polyamic acid that becomes a polyimide PIB having a pyromellimide imide skeleton by imidization treatment. Material is applied. As described above, when different coating materials are applied for each region, it is preferable to apply the materials by an inkjet method. Another method for separating the film L1A and the film L2A of the alignment film AL1 will be described later.

(Embodiment 2)
In the case of the display device DSP3 shown in FIGS. 8 and 9, the display area DA has a plurality of areas DA1 that are not supposed to be folded, and has a foldable area DA2 between adjacent areas DA1. . FIG. 8 is a perspective view of a display device that is a modification to FIG. FIG. 9 is a plan view when the display device shown in FIG. 8 is unfolded. 10 is an enlarged cross-sectional view taken along line AA of FIG. 9. FIG.

In the case of the display device DSP3, as shown in FIG. 8, by folding the display area DA, it is possible to reduce the size when carrying. In addition, the display device DSP3 can visually recognize an image on a large screen by widening the folded display area DA as shown in FIG. Although not shown in FIG. 9, in the display area DA, as in the display device DSP2 shown in FIG. Scanning lines GL, video signal lines SL, common electrodes CE, and the like are arranged.

Since the area DA2 is bent in the display device DSP3, it is necessary to suppress peeling of the alignment film AL1 (see FIG. 10) when the area DA2 is bent, as in the case of the display device DSP1 shown in FIG. As a method for suppressing peeling of the alignment film AL1 in the area DA2, the method described with reference to FIGS. 7 and 6 may be applied, but another method will be described in this embodiment.

As shown in FIG. 10, the display device DSP3 has an organic film 15 between the substrate 10 and the alignment film AL1. The organic film 15 is a planarization film covering the transistor Tr1, as shown in FIG. In the case of the display device DSP3, the thickness TH1 of the organic film 15 overlapping the area DA2 is thinner than the thickness TH2 of the organic film 15 overlapping the area DA1. The coating liquid that forms the alignment film AL1 is a liquid material with a low viscosity at the stage of coating. Therefore, when the surface to be coated has unevenness, the coating liquid is applied more thickly to the concave portions than to the convex portions. As a result, as shown in FIG. 10, the thickness TH3 of the alignment film AL1 overlapping the region DA2 is thicker than the thickness TH4 of the alignment film AL1 overlapping the region DA1.

When the photo-alignment treatment is performed, ultraviolet rays are irradiated from the front surface AL1f (in other words, the surface in contact with the liquid crystal layer LQ) of the alignment film AL1. Therefore, when the thickness of the alignment film AL1 increases, it is difficult for the ultraviolet rays to reach the rear surface on the opposite side of the front surface AL1f. Therefore, at the position overlapping with the area DA2, a large amount of polyimide that is not divided by the ultraviolet rays remains on the back side of the alignment film AL1. As a result, the strength of the alignment film AL1 can be increased at the position overlapping with the area DA2. In this method, for example, the entire alignment film AL1 may be polyimide having a cyclobutane skeleton, such as polyimide PIA1 and polyimide PIA2 shown in FIG.

However, from the viewpoint of increasing the strength of the alignment film AL1 at the position overlapping the region DA2, the alignment film AL1 of the display device DSP3 is a polyamide containing no cyclobutane ring, similarly to the display device DSP1 described with reference to FIG. It is preferable that polyimide imidized with an acid (for example, polyimide PIB having a pyromellitic imide skeleton shown in FIGS. 6 and 7) is contained.

As in the case of the display device DSP1 shown in FIG. 6, the alignment film AL1 of the display device DSP3 shown in FIG. Comparing the thicknesses of the film L1A (see FIG. 6) and the film L2A (see FIG. 6) in contact with the layer LQ, the thickness of the film L2A of the alignment film AL1 is preferably thinner than the thickness of the film L1A. This makes it even more difficult for the alignment film AL1 to peel off even when the region DA2 is bent.

As in the case of the display device DSP2 shown in FIG. 7, the alignment film AL1 of the display device DSP3 shown in FIG. are arranged, and a large number of polyimide PIA2 having an unsubstituted cyclobutane ring are preferably arranged in the region DA2. In the display device DSP3, when the constituent materials of the alignment film are different between the area DA1 and the area DA2, in the step of applying the coating liquid which is the raw material of the alignment film AL1, the coating amount per unit area in the area DA2 is Increase the coating amount per unit area. As a result, as shown in FIG. 10, the alignment film AL1 having a structure in which the thickness TH3 is thicker than the thickness TH4 and in which the regions DA1 and DA2 are made of different materials is obtained.

Except for the differences described above, the display device DSP3 is the same as the display device DSP1 described with reference to FIGS. 1 to 6 or the display device DSP2 shown in FIG. Therefore, overlapping explanations are omitted. As a modified example of the present embodiment, the technique described with reference to FIGS. 8 to 10, for example, the technique of improving the mechanical strength of the bendable region DA2 by reducing the thickness of the organic film 15, can be used. , the display device DSP2 shown in FIG. 1 and the display device DSP1 shown in FIG.

(Embodiment 3)
In this embodiment, a mode of controlling the distribution of polyimide types in the alignment film AL1 by bringing a highly hydrophobic film into contact with the alignment film AL1 will be described. FIG. 11 is an enlarged cross-sectional view of a display device that is a modification of FIG.

The display device DSP4 shown in FIG. 11 has an organic film 15 between the substrate 10 and the alignment film AL1. The organic film 15 is a planarization film covering the transistor Tr1, as shown in FIG. The display device DSP4 also has an insulating film 16 that is an inorganic film covering the organic film 15 . The insulating film 16 is an inorganic insulating film provided between the plurality of pixel electrodes PE and the common electrode CE shown in FIG. The insulating film 16 has an opening 16H at a position overlapping with the region DA2. The alignment film AL1 is in contact with the organic film 15 through the opening 16H of the insulating film 16. As shown in FIG.

The organic film 15 is highly hydrophobic compared to the insulating film 16, which is an inorganic film. In the case of a structure in which the organic film 15 made of a highly hydrophobic material and the alignment film AL1 are in contact with each other, it is possible to control the distribution of polyimide types in the alignment film AL1. For example, when comparing the already explained polyamic acid or polyamic acid ester containing a cyclobutane ring represented by the chemical formula (1) and the polyamic acid containing no cyclobutane ring represented by the chemical formula (2), the polyamic acid represented by the chemical formula (2) has a higher affinity with the organic film 15 . Therefore, in the state of the coating liquid in which these compounds and the solvent are mixed, if part of the coating liquid is in contact with the organic film 15 having high hydrophobicity, a compound of the chemical formula (2) is formed at a position close to the organic film 15 . Polyamic acids that do not contain the indicated cyclobutane ring tend to aggregate. In this case, polyamic acid containing a cyclobutane ring represented by the chemical formula (1) tends to gather at a position away from the organic film 15, that is, on the front surface AL1f side of the alignment film AL1.

According to the present embodiment, the organic film 15 and the alignment film AL1 are in contact with each other at the position overlapping with the region DA2. Therefore, in the alignment film AL1, a material having a higher affinity with the organic film 15 is more likely to gather in the lower film (a film farther from the liquid crystal layer LQ) at the position overlapping with the region DA2. Therefore, when the alignment film AL1 includes a film L2A and a film L2B, for example, as shown in FIG. Polyimide PIA2 having a low affinity for is increased.

In the example shown in FIG. 11, since the pixels PX (see FIG. 1) are also present in the area DA2, the common electrode CE is arranged in the area DA2. However, for example, when the area DA2 is narrow and the pixels PX are not arranged in the area DA2, the common electrode CE may not be arranged. For example, in the case of the display device DSP5 shown in FIG. 12, the insulating film 16 and the common electrode CE shown in FIG. 11 do not exist at the position overlapping the area DA2. FIG. 12 is an enlarged cross-sectional view of a display device that is a modification of FIG. In the case of the display device DSP5, the organic film 15 and the alignment film AL1 are in contact with each other over the entire position overlapping with the area DA2. Therefore, compared to the example shown in FIG. 11, materials having a high affinity for the organic film 15 are more likely to gather on the organic film 15 side. As a result, the polyimide PIA1 (see FIG. 6) having a low affinity for the organic film 15 increases in the film L2A.

Except for the differences described above, the display device DSP4 and the display device DSP5 are the same as the display device DSP1 described with reference to FIGS. 1 to 6, the display device DSP2 shown in FIG. 7, or the display device DSP3 shown in FIGS. It is the same. Therefore, overlapping explanations are omitted. Note that the technique described in this embodiment may be applied in combination with the technique described in another embodiment. For example, the display device DSP4 is applied to a display device in which the display area DA is folded, like the display device DSP3 shown in FIG. 8, as an example. However, like the display device DSP1 shown in FIG. 3, it may be applied to a type of display device in which the regions on both sides of the region DA1 are bent.

(Embodiment 4)
In this embodiment, for example, a member is provided between the area DA1 and the area DA2 shown in FIG. 6, and the member separates the alignment film AL1 in the area DA1 from the alignment film AL1 in the area DA1. do. FIG. 13 is an enlarged cross-sectional view showing the periphery of a boundary between alignment films separated from each other in a display device that is a modification of FIG. 14 is an enlarged plan view of the portion shown in FIG. 13 as viewed from the display surface side. Although FIG. 14 is a plan view, the member SW1 is hatched. The overall structure of the display device DSP6 shown in FIGS. 13 and 14 is similar to the structure of the display device DSP1 shown in FIGS. 1 and 3, or the structure of the display device DSP3 shown in FIGS.

The display device DSP6 includes a flexible substrate 10 having areas DA1 and DA2 on the front surface (main surface, surface) 10f, a liquid crystal layer LQ, and a photodegradable alignment film in contact with the liquid crystal layer LQ. and AL1. The substrate 10 is bendable in the area DA2. The alignment film AL1 includes an alignment film AL11 overlapping with the area DA1 and an alignment film AL12 overlapping with the area DA2. Further, as shown in FIG. 14, a member SW1 for separating the alignment films AL11 and AL12 is arranged between the alignment films AL11 and AL12 in plan view.

The member SW1 is a structure made of an organic material such as resin, and extends in the Y direction along the boundary between the area DA1 and the area DA2. A top portion (front surface) SWf of the member SW1 is positioned higher than the front surface AL1f of the alignment film AL1 (on the side of the substrate 20 shown in FIG. 3). In other words, the distance from the substrate 10 to the top SWf of the member SW1 is longer than the distance from the substrate 10 to the front surface AL1f of the alignment film AL1. In other words, the member SW1 protrudes from the front surface AL1f of the alignment film AL1. Therefore, the member SW1 functions as a separation wall separating the alignment film AL11 and the alignment film AL12.

By arranging a member that functions as a separation wall separating the alignment film AL1 at the boundary between the regions DA1 and DA2, such as the member SW1, the alignment films AL11 and AL12 are made of different materials. easy to do For example, in the manufacturing method of the display device DSP6, the member SW1 is formed before applying the material of the alignment film AL1. After that, the material of the alignment film AL11 is applied to the position overlapping with the area DA1, and the material of the alignment film AL12 is applied to the position overlapping with the area DA2. After that, a drying process is performed to remove the solvent contained in the coating material, and then the material is heated to about 230° C. to imidize the raw material of the polyimide. After that, the imidized alignment film AL1 is subjected to a photo-alignment treatment by irradiating it with ultraviolet rays. In the case of the display device DSP6, the alignment film AL11 and the alignment film AL12 can be reliably separated. can suppress mixing of materials. For example, in the case of the display device DSP1 shown in FIG. 6 and the display device DSP2 shown in FIG. 7, it is necessary to apply different coating materials to the area DA1 and the area DA2. In this case, it is effective to dispose the member SW1 on the boundary between the area DA1 and the area DA2, as in the display device DSP6.

Further, as shown in FIG. 13, each of the alignment film AL11, the alignment film AL12, and the member SW1 is formed on the same base film. In the example shown in FIG. 13, each of the alignment film AL11, the alignment film AL12, and the member SW1 is formed on the insulating film 16, which is an inorganic insulating film. Thus, when the alignment film AL11, the alignment film AL12, and the member SW1 are each formed on the same base film, the alignment film AL11 and the alignment film AL12 can be reliably separated.

Incidentally, in the example shown in FIG. 13, the member SW1 protruding from the front surface AL1f of the alignment film AL1 has been taken up and explained as an example of the separation wall separating the alignment films AL11 and AL12. However, there are various modifications of examples of the separation wall arranged between the alignment film AL11 and the alignment film AL12. For example, in the case of the display device DSP7 shown in FIG. 15, the top SWf of the member SW2 separating the alignment films AL11 and AL12 is continuous with the front surface AL1f of the alignment film AL1. In other words, the top SWf of the member SW2 and the front surface AL1f of the alignment film AL1 are located at approximately the same height. FIG. 15 is an enlarged cross-sectional view of a display device that is a modification of FIG. Although illustration is omitted, the member SW2 shown in FIG. 15 extends in the Y direction along the boundary between the area DA1 and the area DA2, like the member SW1 shown in FIG.

The member SW2 shown in FIG. 15 has liquid repellency with respect to the varnish material contained in the alignment film AL1. The liquid repellency phenomenon occurs, for example, according to the following principle. The raw material for the alignment film AL11 and the raw material for the alignment film AL12 are varnish materials each containing a solvent. The member SW2 is formed, for example, by applying a raw material coating liquid to the boundary between the area DA1 and the area DA2 and then curing the material by heating. The cured member SW2 has poor compatibility (hardly dissolves) in a solvent containing the varnish material. In this case, at the contact interface between the member SW1 and the alignment film AL1, the two repel each other and separate (in other words, liquid-repellent).

In the case of the display device DSP7, the alignment film AL11 and the alignment film AL12 are separated by utilizing the liquid repellency phenomenon described above. In this case, unlike the member SW1 shown in FIG. 13, there is no need to increase (thicken) the height (thickness) of the member SW1. can do. If the height of the top portion SWf can be reduced like the member SW2, it is possible to suppress damage to the alignment film AL1 and the alignment film AL2 (see FIG. 4) due to contact with the top portion of the member SW2.

Except for the differences described above, the display device DSP6 and the display device DSP7 are the same as the display device DSP1 described with reference to FIGS. 1 to 6, the display device DSP2 shown in FIG. 7, or the display device DSP3 shown in FIGS. It is the same. Therefore, overlapping explanations are omitted. Note that the technique described in this embodiment may be applied in combination with the technique described in another embodiment.

(Embodiment 5)
In this embodiment, for example, a member (spacer member) protruding from the underlying film of the alignment film is provided in the bendable region, and the thickness of the alignment film on the member is reduced, or the alignment film is not formed on the member. A non-arranged embodiment will be described. 16 is an enlarged plan view of a display device that is a modification of FIG. 14. FIG. 17 is an enlarged cross-sectional view taken along line AA of FIG. 16. FIG. The overall structure of the display device DSP8 shown in FIGS. 16 and 17 is similar to the structure of the display device DSP3 shown in FIGS. 8 and 9, for example.

The display device DSP8 has flexibility and is in contact with the substrate 10 having the areas DA1, DA2, and DA3 on the front surface (principal surface, surface) 10f, the liquid crystal layer LQ, and the liquid crystal layer LQ. and an alignment film AL1 having The substrate 10 is bendable in the area DA2. Area DA2 is between area DA1 and area DA3. Area DA1 and area DA3 are areas that are not supposed to be folded. In the example shown in FIG. 17, in the area DA2, a member PSB is arranged that protrudes toward the liquid crystal layer LQ from the insulating film 16, which is the underlying film of the alignment film AL1. As shown in FIG. 16, the member PSB extends in the Y direction along the extending direction of the area DA2.

In the case of the display device DSP8, since the member PSB is provided in the area DA2, the thickness of the alignment film AL1 on the member PSB, that is, the thickness of the alignment film AL1 at the position overlapping with the area DA2 is the same as the thickness of the alignment film AL1 at the position overlapping with the area DA1 and the area DA3. thinner than the thickness of Further, depending on the height of the member PSB, the alignment film AL1 may not be arranged on the member PSB. Thus, when there is almost no alignment film AL1 in the area DA2, which is a bendable area, even if the area DA2 is folded, there is no need to consider that the alignment film AL1 is shaved. Therefore, it is possible to prevent the alignment of the liquid crystal molecules of the liquid crystal layer LQ from being hindered by scraps from the alignment film AL1. Moreover, when the bending direction of the area DA2 is assumed in advance, it is preferable that a plurality of grooves are formed in the top portion of the member PSB as shown in FIG. This facilitates bending in the area DA2.

Except for the differences described above, the display device DSP8 is the same as the display device DSP1 described with reference to FIGS. 1 to 6, the display device DSP2 shown in FIG. 7, or the display device DSP3 shown in FIGS. Therefore, overlapping explanations are omitted. Note that the technique described in this embodiment may be applied in combination with the technique described in another embodiment.

(Embodiment 6)
In the present embodiment, a mode of suppressing peeling of the alignment film AL1 in the bendable region by reducing physical stress applied to the alignment film AL1 in the bendable region will be described. FIG. 18 is an enlarged plan view of a display device that is a modification of FIG. 19 is an enlarged cross-sectional view taken along line AA of FIG. 18. FIG. Also, FIG. 20 is an enlarged plan view of a display device which is a modified example of FIG. In FIGS. 18 and 20, the contour of the top of the truncated conical spacer member PS2 is indicated by dotted lines. The overall structure of the display device DSP9 is similar to the structure of the display device DSP1 shown in FIGS. 1 and 3, or the structure of the display device DSP3 shown in FIGS.

The display device DSP9 has a substrate 20 (see FIG. 19) that faces the substrate 10 and is separated from the substrate 10 in the areas DA1 and DA2. The display device DSP9 also has a plurality of spacer members PS arranged between the substrate 10 and the second substrate 20 at positions overlapping the area DA1 and areas DA2.

In the case of a liquid crystal display device, if the thickness of the liquid crystal layer LQ becomes extremely small, the display quality deteriorates. It is preferable that a plurality of spacer members PS are arranged. In the example shown in FIG. 19, each of the plurality of spacer members PS is fixed to the substrate 20 side. However, it is sufficient that the spacer member PS is fixed to either the substrate 10 or the substrate 20, and various modifications other than those shown in FIG. 19 are possible. For example, each of the plurality of spacer members PS may be fixed to the substrate 10 side. Alternatively, a plurality of spacer members PS fixed on the substrate 10 side and a plurality of spacer members PS fixed on the substrate 20 side may be mixed.

The plurality of spacer members PS include a plurality of spacer members PS1 arranged at positions overlapping with the area DA1 and a plurality of spacer members PS2 arranged at positions overlapping with the area DA2. The spacer member PS is a member that prevents the thickness of the liquid crystal layer LQ, or in other words, the separation distance between the substrate 10 and the substrate 20, from becoming extremely small as described above. Therefore, when an external force is applied to the display device DSP9 and the thickness of the liquid crystal layer LQ is temporarily reduced, the top of the spacer member PS comes into contact with the alignment film AL1. At this time, it is preferable to prevent a portion of the alignment film AL1 from peeling off due to contact with the spacer member PS. In particular, in the region DA2 where it is assumed that the film will be bent for use, there is a high possibility that the spacer member PS2 and the alignment film AL2 will come into contact with each other.

Therefore, in the case of the display device DSP9, the spacer members PS2 are arranged in the area DA2 at a high density to reduce the stress generated when each spacer member PS2 contacts the alignment film AL1. As shown in FIG. 18, in the display device DSP9, the arrangement density of the plurality of spacer members PS2 overlapping the area DA2 is higher than the arrangement density of the spacer members PS1 overlapping the area DA1. In other words, in plan view, the distance between adjacent spacer members PS2 is shorter than the distance between adjacent spacer members PS1. In this case, when the region DA2 is bent, the spacer member PS2 and the alignment film AL1 come into contact with each other. It is possible to suppress the occurrence of peeling.

Moreover, from the viewpoint of suppressing the alignment film AL1 from being scraped by the spacer members PS2, it is preferable to increase the area of the top portions of the plurality of spacer members PS2 as in the display device DSP6 shown in FIG. In the case of the display device DSP6 shown in FIG. 20, the width PSW2 of the top of the spacer member PS2 overlapping the area DA2 is wider than the width PSW1 of the top of the spacer member PS1 overlapping the area DA1. It is different from the display device DSP9 shown. In other words, the area of the top of the spacer member PS2 provided in the display device DSP6 is larger than the area of the top of the spacer member PS1.

Each of the plurality of spacer members PS has a shape such as a truncated cone or a truncated pyramid. In the examples shown in FIGS. 18 and 20, the shape of the spacer member PS is a truncated cone. When the spacer member PS and the alignment film AL1 are in contact with each other, the apex of the spacer member PS forming a truncated cone or pyramid comes into contact with the alignment film AL1.

When the areas of the top portions of the plurality of spacer members PS2 are large, the contact area between the top portions of the spacer members PS2 and the alignment film AL1 becomes large. As a result, application of a concentrated force to a part of the alignment film AL1 can be suppressed, so that the alignment film AL1 can be prevented from being scraped by the spacer member PS2 and peeled off.

Except for the differences described above, the display device DSP9 is similar to any of the display devices DSP1 to DSP8 described above. Therefore, overlapping explanations are omitted. Note that the technique described in this embodiment may be applied in combination with the technique described in another embodiment.

The technique described above can be applied to other modifications in addition to the various modifications already described. For example, in the above, as shown in FIG. 3, the areas DA2 and DA3 on both sides of the area DA1 in the display area DA are bent so as to be curved, and as shown in FIG. An example of a display device that can be folded along has been taken and described. In addition to the above, there are various modifications of the folding method and the layout of the foldable area.

The structure of the display device DSP8 described with reference to FIGS. 16 and 17 can be expressed as follows.

a flexible first substrate having a first region, a second region, and a third region on its surface;
a liquid crystal layer;
an alignment film in contact with the liquid crystal layer and having photodegradability;
with
the first substrate is bendable in the second region;
the second region is between the first region and the third region;
A display device, wherein a spacer member protruding from a base film of the alignment film toward the first liquid crystal layer is arranged in the second region.

Within the scope of the idea of the present invention, those skilled in the art can conceive of various modifications and modifications, and it is understood that these modifications and modifications also fall within the scope of the present invention. For example, additions, deletions, or design changes of components, or additions, omissions, or changes of conditions to the above-described embodiments by those skilled in the art are also subject to the gist of the present invention. is included in the scope of the present invention as long as it has

INDUSTRIAL APPLICABILITY The present invention can be used for display devices and electronic devices incorporating display devices.

10, 20 substrates 10b, 20b rear surface (main surface, rear surface)
10f, 20f front surface (principal surface, front surface)
11, 12, 13, 14, 16, OC1 insulating film 15 organic film (flattening film, organic insulating film)
16H openings AL1, AL11, AL12, AL2 alignment film AL1f front surface ALP alignment axis BM light shielding film BND sealing material CD common electrode drive circuit CDP conductor pattern CE common electrode CF color filter DA display area DA1 area (first area)
DA2 area (second area)
DA3 area (third area)
DE drain electrode DSP1, DSP2, DSP3, DSP4, DSP5, DSP6, DSP7, DSP8 display device GD scanning line drive circuit (gate drive circuit)
GE gate electrode GL scanning line (gate line)
Gsi scanning signal L1A, L1B, L2A, L2B, L3A, L3B layer (part)
LQ liquid crystal layer PE pixel electrode PFR peripheral region PI1, PIA1, PIA2, PIB polyimide PI2 composition PS, PS1, PS2 spacer member PX pixel SCR semiconductor region (semiconductor layer)
SD Signal line drive circuit SE Source electrode SL Video signal line (source line)
Spic video signals PSB, SW1, SW2 members PSW1, PSW2 width SUB1, SUB2 substrate SWf top (front)
Tr1 Transistor UVP Polarization axis

Claims (7)

a flexible first substrate having a first region and a second region on its surface;
a first transistor on the first substrate; and
a liquid crystal layer;
an alignment film in contact with the liquid crystal layer and having photodegradability;
a first organic film between the first substrate and the alignment film and covering the first transistor;
a first inorganic film covering the first organic film;
with
the first substrate is bendable in the second region;
The first inorganic film has an opening in the second region,
the thickness of the first organic film in the second region is thinner than the thickness of the first organic film in the first region;
the alignment film is in contact with the first organic film through the opening of the first inorganic film in the second region;
The alignment film is in contact with the liquid crystal layer and includes a first film containing a photodegradable material,
The display device, wherein the thickness of the first film in the second region is thinner than the thickness of the first film in the first region. the alignment film further comprises a second film between the first film and the first substrate;
2. The display device according to claim 1, wherein the thickness of said second film in said second region is thicker than the thickness of said second film in said first region. a flexible first substrate having a first region and a second region on its surface;
a liquid crystal layer;
an alignment film in contact with the liquid crystal layer;
a first transistor on the first substrate; and
a first organic film between the first substrate and the alignment film and covering the first transistor;
a first inorganic film covering the first organic film;
with
the first substrate is bendable in the second region;
The first inorganic film has an opening in the second region,
the alignment film is in contact with the first organic film through the opening of the first inorganic film in the second region;
A display device, wherein the thickness of the first organic film in the second region is thinner than the thickness of the first organic film in the first region. a second substrate facing the first substrate and separated from the first substrate in the first region and the second region;
a plurality of spacer members arranged between the first substrate and the second substrate at positions overlapping with the first region and positions overlapping with the second region;
further comprising
4. The display device according to claim 3 , wherein the arrangement density of the second spacer members at the position overlapping with the second region is higher than the arrangement density of the first spacer members at the position overlapping with the first region. a second substrate facing the first substrate and separated from the first substrate in the first region and the second region;
a plurality of spacer members arranged between the first substrate and the second substrate at positions overlapping with the first region and positions overlapping with the second region;
further comprising
The width of the top portion of the second spacer member overlapping the second region is wider than the width of the top portion of the first spacer member overlapping the first region. Display device as described. wherein the alignment film is in contact with the liquid crystal layer and has a first film containing a photodegradable material and a second film between the first film and the first substrate;
6. The display device according to claim 1 , wherein said first film contains a polyimide material having a cyclobutane ring. 7. The display device according to claim 6 , wherein the second film contains a polyimide material having a pyromellitic imide skeleton.

Images