CN113176683A

CN113176683A - Display device

Info

Publication number: CN113176683A
Application number: CN202011448857.1A
Authority: CN
Inventors: 小岛彻也; 冲田光隆
Original assignee: Japan Display Inc
Current assignee: Japan Display Inc
Priority date: 2020-01-27
Filing date: 2020-12-09
Publication date: 2021-07-27
Anticipated expiration: 2040-12-09
Also published as: JP2021117354A; CN113176683B

Abstract

The invention provides a display device capable of arranging a sensor or an imaging element at a position overlapping a display surface, and a manufacturing method thereof. The display device includes a first optical unit, an array substrate, a liquid crystal layer, a counter substrate on the liquid crystal layer, a second optical unit, and a buffer film on the second optical unit. The first optical unit includes a first linear polarizer, a resin film having an opening and located on the first linear polarizer, and a first wave-blocking sheet in the opening. The display substrate is positioned on the first optical unit and has a pixel electrode. The liquid crystal layer is positioned on the array substrate. The second optical unit has a second wave-resistance sheet overlapping the first wave-resistance sheet, and a second linear polarizer on the second wave-resistance sheet, and is located on the counter substrate.

Description

Display device

Technical Field

The present invention relates to a display device and a method of manufacturing the display device. For example, the present invention relates to a display device having a pixel including a liquid crystal element and a method for manufacturing the same.

Background

In recent years, many small-sized electronic portable terminals having a display function are designed so that the area other than the display surface (frame area, peripheral area) becomes extremely narrow, because the display surface is enlarged to improve the visibility of the display and the design. In such design guidelines, the area required for elements for supporting the functions of the electronic portable terminal, such as an image pickup element, a sensor, and an audio input/output device, is strictly limited. Therefore, a technique has been proposed in which a cutout or an opening is provided in a part of the display surface, and an image pickup device, a sensor, or the like is disposed therein. For example, patent documents 1 and 2 disclose a technique of forming a light-transmitting region in a part of a display surface by configuring a display device so that the structure and driving method of the part of the display surface are different from those of other parts. By using the light-transmitting region, various elements can be arranged at a position overlapping the display surface.

Documents of the prior art

Patent document

Patent document 1: JP 2010-15015 publication

Patent document 2: JP 2869452A

Disclosure of Invention

An object of an embodiment of the present invention is to provide a display device in which a sensor or an imaging element can be disposed at a position overlapping a display surface, and a method for manufacturing the same. For example, one of the embodiments is to provide a display device having liquid crystal elements with different operation modes, and a method for manufacturing the same.

One embodiment of the present invention is a display device. The display device includes a first optical unit, an array substrate on the first optical unit, a liquid crystal layer on the array substrate, a counter substrate on the liquid crystal layer, a second optical unit on the counter substrate, and a buffer film on the second optical unit. The first optical unit includes a first linear polarizer, a resin film having an opening and located on the first linear polarizer, and a first wave-blocking sheet in the opening. The array substrate is provided with a pixel electrode. The second optical unit has a second wave-resistance sheet overlapping the first wave-resistance sheet, and a second linear polarizing plate on the second wave-resistance sheet.

One embodiment of the present invention is a display device. The display device includes a first linear polarizer, a first resistance plate on the first linear polarizer, a light control element on the first resistance plate, a second resistance plate on the light control element, a second linear polarizer on the second resistance plate and covering the second resistance plate, and a buffer film on the second linear polarizer. The light control element is composed of a pair of electrodes and a liquid crystal layer. The second wave resistance sheet is overlapped with the first wave resistance sheet and has a bent shape. The buffer film has a flat upper surface from the second wave-resistance plate to the second linear polarizer.

One embodiment of the present invention is a method for manufacturing a display device. The manufacturing method comprises the following steps: a liquid crystal layer disposed between an array substrate having pixel electrodes and a counter substrate; fixing a first optical unit under the array substrate; fixing a second optical unit on the counter substrate; and forming a buffer film on the second optical unit. The first optical unit has a first linear polarizer and a first wave-resistance plate overlapping the first linear polarizer. The second optical unit has a second wave-resistance sheet and a second linear polarizing plate covering the second wave-resistance sheet. The first optical unit and the second optical unit are fixed so that the first wavelength-blocking sheet and the second wavelength-blocking sheet overlap each other. The buffer film is formed by disposing a precursor of a resin on the second optical unit and curing the precursor.

Drawings

Fig. 1 is a schematic plan view of a display device according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a display device according to an embodiment of the present invention.

Fig. 3 is a schematic top view of a pixel and a dimming element of a display device according to an embodiment of the invention.

Fig. 4 is a schematic top view of a pixel of a display device according to an embodiment of the present invention.

Fig. 5 is a schematic cross-sectional view of a pixel of a display device according to an embodiment of the present invention.

Fig. 6 is a schematic plan view of a light control element of a display device according to an embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view of a light control element of a display device according to an embodiment of the present invention.

Fig. 8A is a schematic top view of a light control element of a display device according to an embodiment of the present invention.

Fig. 8B is a schematic top view of a light control element of a display device according to an embodiment of the present invention.

Fig. 9A is a schematic cross-sectional view of a light control element of a display device according to an embodiment of the present invention.

Fig. 9B is a schematic cross-sectional view of a light adjusting element of a display device according to an embodiment of the present invention.

Fig. 10A is a schematic cross-sectional view of a light control element of a display device according to an embodiment of the present invention.

Fig. 10B is a schematic cross-sectional view of a light control element of a display device according to an embodiment of the present invention.

Fig. 11A is a schematic cross-sectional view illustrating optical characteristics of the light modulation element.

Fig. 11B is a schematic cross-sectional view illustrating optical characteristics of the light modulation element.

Fig. 12A is a schematic perspective view illustrating an operation of the display device according to the embodiment of the present invention.

Fig. 12B is a schematic perspective view illustrating an operation of the display device according to the embodiment of the present invention.

Fig. 13A is a schematic perspective view illustrating an operation of the display device according to the embodiment of the present invention.

Fig. 13B is a schematic perspective view illustrating an operation of the display device according to the embodiment of the present invention.

Fig. 14A is a schematic perspective view illustrating an operation of the display device according to the embodiment of the present invention.

Fig. 14B is a schematic perspective view illustrating an operation of the display device according to the embodiment of the present invention.

Fig. 15A is a schematic cross-sectional view illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Fig. 15B is a schematic cross-sectional view illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Fig. 15C is a schematic cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention.

Fig. 16A is a schematic cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention.

Fig. 16B is a schematic cross-sectional view illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Fig. 17A is a schematic cross-sectional view illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Fig. 17B is a schematic cross-sectional view illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Fig. 17C is a schematic cross-sectional view illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Fig. 18 is a schematic cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention.

Fig. 19 is a schematic cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention.

Fig. 20 is a schematic cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention.

Wherein the reference numerals are as follows:

100: display device, 200: backlight unit, 202: reflection plate, 204: light guide plate, 206: prism sheet, 208: light diffusion film, 212: adhesive layer, 214: light source, 216: through-hole, 300: display module, 302: substrate, 302: array substrate, 304: counter substrate, 304: substrate, 306: sealing material, 308: liquid crystal layer, 309: optical unit, 309-1: first optical unit, 309-2: second optical unit, 310: linear polarizer, 310-1: first linear polarizer, 310-2: second linear polarizer, 312: λ/4 wave plate, 312-1: first λ/4 wave plate, 312-2: second λ/4 plate, 314: λ/2 wave plate, 314-1: first λ/2 wave plate, 314-2: second λ/2 wave plate, 316: resin film, 318: adhesive layer, 318-1: first adhesive layer, 318-2: second adhesive layer, 319: gap, 320: display area, 322: pixel, 324: dimming element, 326: scanning line driver circuit, 328: signal line drive circuit, 330: terminal, 340: gate lines, 342: video signal line, 344: power supply line, 346: transistors, 348: common electrode, 349: lower electrode, 350: pixel electrode, 351: upper electrode, 352: semiconductor film, 354: drain electrode, 356: opening, 357: opening, 358: dimming control line, 360: undercoat layer, 362: gate insulating film, 364: interlayer insulating film, 366: planarizing film, 368: interelectrode insulating film, 370: alignment film, 370-1: first alignment film, 370-2: second alignment film, 372: overcoat, 374: color filter, 376: black matrix, 378: spacer, 380: buffer film, 382: cover plate, 400: photoelectric conversion element

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings and the like. However, the present invention can be carried out in various ways without departing from the scope of the present invention, and is not limited to the description of the embodiments explained below.

In order to make the description more clear, the drawings schematically show the width, thickness, shape, and the like of each part than in an actual form, but the drawings are merely examples and do not limit the explanation of the present invention. In the present specification and the drawings, the same reference numerals are given to elements having the same functions as those described with reference to the already-shown drawings, and redundant description thereof may be omitted. When a plurality of configurations which are the same or similar are collectively referred to, a reference numeral is used, and when each configuration is referred to, a "-" and a natural number are added thereto.

In the present specification and the scope of protection, when a plurality of films are formed by processing a certain film, the plurality of films may have different functions and actions. However, these films are formed as the same layer in the same step, and therefore have the same material. Therefore, these plural films are defined to exist in the same layer.

In the present specification and the scope of protection, when the expression "at … …" is used in the case where another structure is disposed on a certain structure, the expression includes, unless otherwise specified, both the case where another structure is disposed directly above the certain structure so as to be in contact with the certain structure and the case where another structure is further disposed above the certain structure with the other structure interposed therebetween.

In the present specification and the scope of protection, the expression "a certain structural body is exposed from another structural body" means that a part of a certain structural body is not directly or indirectly covered with another structural body, and a part not covered with another structural body also includes a part directly or indirectly covered with another structural body.

< embodiment 1 >

In this embodiment, a structure of a display device 100 according to one embodiment of the present invention will be described.

1. Is formed integrally

The entire structure of the display device 100 will be described with reference to fig. 1 and 2. Fig. 1 is a schematic top view of a display device 100, and fig. 2 shows a schematic view of a cross section along a chain line a-a' of fig. 1. As shown in fig. 2, the display device 100 has a display module 300. The display device 100 may further include a backlight unit 200 and a photoelectric conversion element 400 under the display module 300. In fig. 2, an example in which two photoelectric conversion elements 400 are provided is shown.

1-1. display module

As shown in fig. 2, the display module 300 has a pair of

substrates

302 and 304 fixed to each other by a sealing material 306, and a liquid crystal layer 308 sealed by the pair of

substrates

302 and 304 and the sealing material 306. Hereinafter, the

substrates

302 and 304 are referred to as an array substrate 302 and a counter substrate 304, respectively. The sealing material 306 is sandwiched between the array substrate 302 and the counter substrate 304, and as shown in fig. 1, a single closed shape is formed on the array substrate 302. The inside of the closed shape is filled with a liquid crystal layer 308. Therefore, a single liquid crystal layer 308 is formed in a single closed space formed by the array substrate 302, the counter substrate 304, and the sealing material 306. A unit including the single liquid crystal layer 308, the array substrate 302, the counter substrate 304, and the sealing material 306 is a single liquid crystal cell. One display device 100 has a single liquid crystal cell.

Also, the display module 300 has a first optical unit 309-1 under the array substrate 302 and a second optical unit 309-2 over the opposite substrate 304.

The first optical unit 309-1 includes a first linear polarizer 310-1, a first 1/4 wave-blocking plate (hereinafter referred to as a first λ/4 wave plate) 312-1, and a resin film 316, and is arranged such that the first λ/4 wave plate 312-1 and the resin film 316 are sandwiched between the array substrate 302 and the first linear polarizer 310-1. The resin film 316 is provided with an opening, and the first λ/4 wave plate 312-1 is disposed in the opening. The first optical unit 309-1 is fixed to the lower surface of the array substrate 302 by a first adhesive layer 318-1.

The second optical unit 309-2 includes a second 1/4 wave-blocking plate (hereinafter referred to as a second λ/4 wave plate) 312-2 and a second linear polarizer 310-2 located on the second λ/4 wave plate and overlapping the second λ/4 wave plate, and is disposed such that the second λ/4 wave plate 312-2 is sandwiched between the second linear polarizer 310-2 and the opposite substrate 304. The second optical unit 309-2 is fixed to the upper surface of the opposite substrate 304 by a second adhesive layer 318-2.

Accordingly, the first and second linear polarizers 310-1 and 310-2 are configured to sandwich the resin film 316, the first λ/4 wave plate 312-1, and the second λ/4 wave plate 312-2. The first λ/4 wave plate 312-1 and the second λ/4 wave plate 312-2 are disposed so as to overlap with a through hole 216 provided in a light control device 324 and the backlight unit 200, which will be described later. Fig. 2 shows an example in which two pairs of λ/4 wave plates 312 are respectively overlapped with the through holes 216.

The display module 300 further includes a buffer film 380 on the second optical unit 309-2. The buffer film 380 may also be in contact with the second linear polarizer 310-2. The buffer film 380 absorbs the irregularities caused by the second λ/4 plate 312-2, and has a function of providing a flat upper surface. The display module 300 may further include a cover plate 382 fixed to the buffer film 380.

1-2. backlight Unit

As shown in fig. 2, the backlight unit 200 is provided below an array substrate 302, and includes, as basic components, a reflection plate 202, a light guide plate 204 on the reflection plate 202, a light source 214 provided on a side surface of the light guide plate 204, and various optical films formed on the light guide plate 204. The optical film may have any structure, and fig. 2 shows, as an example, an optical film obtained by combining a prism sheet 206 and a light diffusion film 208. The backlight unit 200 may also be fixed to the display module 300 by an adhesive layer 212.

The light source 214 includes a light emitting element such as a light emitting diode or a cold cathode tube. The light-emitting element preferably has a light-emitting wavelength covering the entire visible light region. Light from the light source 214 enters the light guide plate 204, and the light guide plate 204 is configured to diffuse and reflect the light entering therein and to uniformly emit the light in the direction of the display module 300. The reflective plate 202 is provided on the opposite side of the light guide plate 204 from the display module 300, and reflects light emitted to the opposite side of the display module 300 and returns the light to the light guide plate 204. The prism sheet 206 is provided to collect and emit light emitted from the light guide plate 204 in the front direction of the display module 300, and is disposed on the surface of the prism sheet 206, for example, in a stripe shape having a plurality of prism-shaped irregularities on the surface. The light diffusion film 208 is a member for uniformizing light, and may include light-diffusing fine particles and a matrix of a polymer for fixing the fine particles.

The backlight unit 200 is provided with at least one through hole 216 that penetrates at least the light guide plate 204 and the reflection plate 202. The number of through holes 216 may be the same as the number of photoelectric conversion elements 400, and fig. 2 shows an example in which two through holes 216 corresponding to two photoelectric conversion elements 400 are provided. In the example shown in fig. 2, though the prism sheet 206 and the light diffusion film 208 are provided with through-holes at positions overlapping the through-holes 216, the through-holes are not necessarily provided at these portions.

1-3. photoelectric conversion element

The photoelectric conversion element 400 is provided so as to overlap the through-hole 216 and the pair of λ/4 wave plates 312 (i.e., the first λ/4 wave plate 312-1 and the second λ/4 wave plate 312-2 that overlap each other), respectively. Fig. 2 shows a state in which two photoelectric conversion elements 400 are respectively overlapped with the corresponding through-holes 216 and the pair of λ/4 wave plates 312. The photoelectric conversion element 400 has an arbitrary function or structure, and examples thereof include an image pickup element such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary metal oxide Semiconductor) image sensor, and an optical sensor.

2. Structure of display module

The structure of the display module 300 will be described in detail below.

2-1. layout

A plurality of pixels 322, light control elements 324, circuits for driving these (a scanning line driving circuit 326, a signal line driving circuit 328), terminals 330, and the like (fig. 1) are formed of various patterned semiconductor films, insulating films, and conductive films laminated on the array substrate 302. Fig. 1 shows an example in which two dimming elements 324 are provided, but the number of the dimming elements 324 is not limited, and may be one, or may include three or more dimming elements 324. As will be described later, liquid crystal elements having different operation modes are formed in the pixel 322 and the light control element 324. Here, the liquid crystal element refers to a pair of electrodes and a portion of the liquid crystal layer 308 driven by the pair of electrodes.

The pixels 322 are configured to transmit a part of light from the backlight unit 20 to the outside of the display device 100. The pixel 322 is a minimum unit to which single color information is given, and has a pixel circuit and a liquid crystal layer 308 overlapping with the pixel circuit as a basic configuration. The configuration of the plurality of pixels 322 is not limited, and the plurality of pixels 322 may be configured in various arrays such as a stripe array, a mosaic array, a triangle array, and the like. The area defined by the plurality of pixels 322 is a display area 320. The pixels 322 are arranged so as not to overlap the through holes 216.

Fig. 3 shows a schematic top view of a dimming element 324 and a portion of a display area 320 surrounding the dimming element 324. The light control element 324 is located inside the display region 320, and one light control element 324 is disposed so as to be surrounded by a plurality of pixels 322. The light control element 324 can be larger in size (area) than the pixel 322. The shape of the light control device 324 is not limited to the circular shape shown in fig. 3, and may be determined arbitrarily. For example, any shape such as a square, rectangle, trapezoid, etc., a quadrangle, a polygon, an ellipse, etc. can be used.

The light control element 324 is provided at a position overlapping the through hole 216 (fig. 2). Therefore, the dimming element 324 overlaps the photoelectric conversion element 400. The light control element 324 also includes a pixel circuit having a different structure from that of the pixel circuit in the pixel 322, and the light control element 324 includes the pixel circuit as a basic structure and the liquid crystal layer 308 overlapping the pixel circuit. The light control element 324 has a function of controlling the transmission of external light, and thus can adjust the amount of light incident on the photoelectric conversion element 400.

Various signal lines (gate lines, video signal lines, initialization signal lines, power supply lines, and the like), not shown, extend from the scanning line driving circuit 326 and the signal line driving circuit 328 to the display region 320, and these signal lines are electrically connected to the corresponding pixels 322 and the light control elements 324. A connector such as a Flexible Printed Circuit (FPC), not shown, is connected to the terminal 330, and a signal and a power source supplied from an external circuit (not shown) are supplied to the scanning line driver circuit 326, the signal line driver circuit 328, the pixels 322, and the light control element 324 via the connector and the terminal 330. The scanning line driver circuit 326 and the signal line driver circuit 328 drive the pixel circuits in the pixels 322 and the light control element 324 based on the supplied signals and power. Thereby, the alignment of the liquid crystal molecules in the liquid crystal layer 308 is controlled, the light amount of light supplied from the backlight unit 200 is controlled in the pixel 322, and the amount of incident external light is controlled in the light control element 324.

2-2. pixel

Fig. 4 shows an example of the layout of the pixels 322, and fig. 5 shows a schematic view of a cross section along the chain line B-B' of fig. 4. As shown in these figures, the pixel circuit of the pixel 322 includes a pixel electrode 350, a common electrode 348, a transistor 346 electrically connected to the pixel electrode 350, a liquid crystal layer 308 provided over the pixel electrode 350 and the common electrode 348, alignment films (a first alignment film 370-1 and a second alignment film 370-2) which sandwich the liquid crystal layer, and the like. The pixel 322 is electrically connected to a gate line 340 extending from the scanning line driving circuit 326, a video signal line 342 extending from the signal line driving circuit 328, and a power supply line 344. The pixel circuits shown in these drawings are merely examples, and the pixel circuits may include elements such as a storage capacitor and other transistors.

As shown in fig. 5, the pixel circuit is provided on the array substrate 302 via the undercoat layer 360. The array substrate 302 includes a material selected from plastics including polymers such as glass, quartz, phosphoramide, etc. The undercoat layer 360 functions as a protective film for preventing diffusion of impurities located in the array substrate 302, and is composed of one or a plurality of films including a silicon-containing inorganic compound such as silicon oxide and silicon nitride.

The transistor 346 includes a semiconductor film 352, a part of a gate insulating film 362, a part of a gate line 340, a part of an interlayer insulating film 364, a part of a video signal line 342, a drain electrode 354, and the like. A part of the gate line 340 overlapping with the semiconductor film 352 functions as a gate electrode of the transistor 346, and a part of the video signal line 342 functions as a source electrode of the transistor 346. An opening reaching the semiconductor film 352 is provided in the gate insulating film 362 and the interlayer insulating film 364, and the drain electrode 354 and the source electrode are electrically connected to the semiconductor film 352 through the openings. In the example shown here, the transistor 346 is a top-gate transistor, but the transistor 346 may be a transistor having another structure (e.g., a bottom-gate transistor).

A planarization film 366 is provided on the transistor 346, and irregularities formed by the transistor 346 are absorbed to form a flat surface. The planarization film 366 includes a polymer material such as acrylic resin, epoxy resin, silicone resin, or phosphoramide.

A common electrode 348 is disposed on the planarization film 366. The common electrode 348 is formed to be common to the plurality of pixels 322. For example, as shown in fig. 4, the common electrode 348 is disposed in parallel with the gate lines 340 and is shared by a plurality of pixels 322 connected to one gate line 340. Although not shown, the common electrode 348 may be disposed in parallel with the video signal line 342 so as to be shared by a plurality of pixels 322 connected to one video signal line 342, or may be provided so as to be shared by all the pixels 322.

The common electrode 348 is provided with a power supply line 344 connected to the common electrode 348. The power supply line 344 may be disposed so as to overlap the video signal line 342. A potential (Vcom) slightly lower than, for example, the maximum and minimum intermediate potentials of the video signal supplied to the video signal line 342 is supplied to the power line 344, and the potential is applied to the common electrode 348. Although not shown, the power supply line 344 may be provided below the common electrode 348.

A pixel electrode 350 is formed on the common electrode 348 and the power supply line 344 with an inter-electrode insulating film 368 interposed therebetween. The pixel electrode 350 is electrically connected to the drain electrode 354 through an opening provided in the planarization film 366 or the interelectrode insulating film 368. Thus, a video signal supplied to the video signal line 342 is applied to the pixel electrode 350 via the transistor 346, and the potential of the pixel electrode 350 is independently controlled for each pixel 322 in accordance with the video signal. As shown in fig. 4, the pixel electrode 350 has a slit having a closed shape, and a portion of the pixel electrode 350 is exposed from the slit. Although not shown, the pixel electrode 350 may have a notch instead of the slit. Or may have both slits and notches. The slit is a closed-shaped opening provided in the pixel electrode 350, and the outer periphery thereof is the inner periphery of the pixel electrode 350. When the outer circumference of the opening is a portion of the outer circumference of the pixel electrode 350, the opening is defined as a notch.

A first alignment film 370-1 is disposed on the pixel electrode 350. The first alignment film 370-1 includes a polymer such as polyimide, and the surface thereof is adjusted to control the alignment of liquid crystal molecules included in the liquid crystal layer 308. Specifically, the surface of the first alignment film 370-1 is rubbed or irradiated with ultraviolet light once or more than once when the first alignment film 370-1 is formed of a photocurable resin having liquid crystal cells, thereby aligning the liquid crystal cells in the first alignment film 370-1. Alternatively, a film of photodegradable polyimide or the like may be formed and irradiated with polarized ultraviolet rays. Hereinafter, the alignment control of the alignment film 370 will be collectively referred to as alignment treatment. In addition, the orientation treatment direction is defined as the direction in which the liquid crystal molecules are oriented in the first alignment film 370-1 subjected to the orientation treatment in the absence of an electric field.

The counter substrate 304 is provided with a color filter 374 and a black matrix 376. The color filter 374 gives color to light from the backlight unit 200, and as a result, the pixel 322 can give color information. The color filters 374 are configured to have different optical characteristics between adjacent pixels 322. The black matrix 376 has a low transmittance with respect to visible light or substantially does not transmit visible light, and is provided so as to cover the transistors 346, the video signal lines 342, and the gate lines 340. In any configuration, an overcoat layer 372 covering the color filter 374 or the black matrix 376 may be provided on the counter substrate 304. The counter substrate 304 further has a second alignment film 370-2 covering the color filter 374 or the black matrix 376. Similarly to the first alignment film 370-1, the second alignment film 370-2 was also subjected to alignment treatment in the same direction as the first alignment film 370-1.

The liquid crystal layer 308 is provided between the array substrate 302 and the counter substrate 304, and the pixel electrode 350 or the common electrode 348, the first alignment film 370-1, and the second alignment film 370-2 are sandwiched between the array substrate 302 and the counter substrate 304. The liquid crystal layer 308 includes liquid crystals exemplified by positive liquid crystals having positive dielectric anisotropy. As described above, the liquid crystal layer 308 is sealed in the space formed by the sealing material 306, the array substrate 302, and the counter substrate 304, and the display device 100 has a single liquid crystal cell. Thus, one liquid crystal layer 308 is shared by all pixels 322 and the dimming element 324.

The distance between the array substrate 302 and the counter substrate 304 is controlled by, for example, spacers 378 formed on the array substrate 302. The spacers 378 include a polymer such as an acrylic resin or an epoxy resin, and are provided for each pixel 322 or for each plurality of pixels 322. The spacers 378 may be disposed on the array substrate 302 or may not be fixed to the array substrate 302 or the opposite substrate 304.

As described above, the display device 100 has the first optical unit 309-1 and the second optical unit 309-2, which are respectively fixed to the lower surface of the array substrate 302 and the upper surface of the opposite substrate 304 by a pair of adhesive layers (the first adhesive layer 318-1, the second adhesive layer 318-2). The resin film 316 and the pair of linear polarizing plates 310 are arranged so as to overlap the display region 320, and the pixel 322 and the resin film 316 are sandwiched by the pair of linear polarizing plates 310. In the display device 100, a pair of linear polarizers 310 have a cross-polarization (cross nicol) relationship. That is, the first linear polarizer 310-1 and the second linear polarizer 310-2 are arranged such that the transmission axes are orthogonal to each other.

The linear polarizer 310 can have a known configuration. Typically, a polarizing plate in which a film of polyvinyl alcohol that adsorbs iodine and extends in one direction is sandwiched between films of cellulose-based polymers such as triacetylcellulose may be used. The linear polarizer 310 may further have a protective film including a polymer exemplified by a polyester fiber such as polyethylene terephthalate on one side or both sides. The λ/4 plate 312 may have a known configuration, and the description thereof is omitted here.

The resin film 316 is a film including a polymer that can transmit at least part of visible light, and is selected from, for example, a cellulose polymer such as epoxy resin, acrylic resin, silicone resin, and triacetylcellulose, and a polyester fiber such as polyethylene terephthalate or polyethylene naphthalate. In the first optical unit 309-1, the resin film 316 may be in contact with the linear polarizer 310. The resin film 316 does not need to have a property of polarizing light. I.e. may not have a transmission axis.

The buffer film 380 is also a film including a polymer capable of transmitting at least a part of visible light, and can include a material capable of functioning as the resin film 316. As will be described later, the thickness of the buffer film 380 absorbs the curved shape of the second λ/4 plate 312-2 or the second linear polarizer 310-2 provided so as to overlap the light control element 324, and is adjusted so as to provide a flat upper surface on the second λ/4 plate 312-2. Therefore, the thickness of the buffer film 380 may be different from that of the resin film 316, and may be, for example, 50 μm to 500 μm, 50 μm to 250 μm, or 70 μm to 150 μm. The resin film 316 may be thinner than the buffer film 380.

The mask 382 may comprise a polymer, or glass or quartz, or the like, capable of transmitting visible light. In the case of including a polymer, polyolefins such as polypropylene, and polymers such as polyimide, phosphoramide, polycarbonate may be included in addition to the polymer that can be used as the resin film 316 or the buffer film 380. The cover plate 382 is preferably flat on both sides at least in the region overlapping the light control element 324.

The preferential buffer film 380 preferably has a low refractive index, and is preferably substantially equal to the refractive index of the linear polarizer 310, the λ/4 plate 312, or the adhesive layer 318. For example, the refractive index of the buffer film 380 is preferably 1.50 to 1.65 or 1.50 to 1.60. The difference between the refractive index of the buffer film 380 and the refractive index of the adhesive layer 318, the linear polarizer 310, or the λ/4 plate 312 is also preferably 0.15 or less or 0.10 or less. This suppresses reflection or refraction of light at the interface between the buffer film 380 and the second linear polarizer 310-2, the interface between the second linear polarizer 310-2 and the second λ/4 plate 312-2, and the interface between the second λ/4 plate 312-2 and the second adhesive layer 318-2. As a result, as will be described later, the occurrence of distortion in the captured image can be suppressed by the flare of the light control device 324 or the light control device 324.

In each pixel 322, the initial alignment of the liquid crystal molecules contained in the liquid crystal layer 308 is mainly determined by the alignment treatment direction of the first alignment film 370-1 and the second alignment film 370-2. In the absence of an electric field, the liquid crystal molecules are aligned in a direction substantially parallel to the surface of the array substrate 302 along the alignment treatment direction. When a potential difference is applied between the pixel electrode 350 and the common electrode 348, the initial orientation changes. That is, the liquid crystal molecules are rotated in a plane substantially parallel to the surface of the array substrate 302 by an electric field generated between the pixel electrode 350 and the common electrode 348 and substantially parallel to the surface of the array substrate 302. As a result, the alignment direction of the liquid crystal molecules changes, and the change is controlled by the potential difference between the pixel electrode 350 and the common electrode 348, whereby the light transmittance of the liquid crystal layer 308 is controlled, and a harmonic display is realized. In this manner, an FFS (Fringe Field Switching) liquid crystal element is formed in each pixel 322.

Although not shown, the liquid crystal element of each pixel 322 may be an IPS (In-Plane Switching) liquid crystal element. In this case, the common electrode 348 further includes a slit or a notch, and the pixel 322 is configured to be in the same layer as the pixel electrode 350.

2-3 light modulation element

Fig. 6 shows a top view of the dimming element 324, and fig. 7 shows a schematic view along a dotted line C-C' of fig. 6. In FIG. 6, the second λ/4 plate 312-2 or the second linear polarizer 310-2 included in the second optical unit 309-2 is not shown. As shown in these figures, the pixel circuit of the light control element 324 includes a lower electrode 349 overlapping the through hole 216, an upper electrode 351 overlapping the lower electrode 349, and the liquid crystal layer 308 disposed between the lower electrode 349 and the upper electrode 351. The dimming element 324 is electrically connected to a dimming control line 358 extending from the signal line driver circuit 328. A dimming control signal is supplied from the signal line drive circuit 328 to the dimming control line 358, and the potential of the signal is applied to the lower electrode 349 via the dimming control line 358. As shown in fig. 6, the lower electrode 349 may be provided to cover the entire through hole 216. Alternatively, although not shown, the lower electrode 349 may be provided so as to cover the entire light-receiving surface of the photoelectric conversion element 400.

The pixel circuit of the light control element 324 is also provided on the array substrate 302 via the undercoat layer 360, similarly to the pixel circuit of the pixel 322. The dimming control line 358 is provided on the array substrate 302 via the undercoat layer 360 and the gate insulating film 362 or the interlayer insulating film 364 extending from the pixel 322, and a planarization film 366 is disposed thereon. The opening 356 reaching the dimming control line 358 is provided in the planarization film 366, and the lower electrode 349 is disposed on the planarization film 366 so as to cover the opening 356, whereby the lower electrode 349 and the dimming control line 358 are electrically connected. In the present embodiment, a single lower electrode 349 is disposed in one light control element 324. In other words, a single liquid crystal element including a single lower electrode 349, a single upper electrode 351 overlapping with the single lower electrode 349, and a part of the liquid crystal layer 308 therebetween is formed in one light control element 324.

The lower electrode 349 is covered with the first alignment film 370-1 extending from the pixel 322. Therefore, the first alignment film 370-1 is shared by the pixels 322, and the alignment processing direction thereof is the same as that of the alignment film in the pixels 322.

The counter substrate 304 is provided with an upper electrode 351. The upper electrode 351 may be configured to be supplied with the same potential (Vcom) as the common electrode 348, or may be configured to be supplied with a different potential from the common electrode 348. When the overcoat layer 372 is provided in the pixel 322, the upper electrode 351 is provided on the counter substrate 304 with the overcoat layer 372 interposed therebetween. The counter substrate 304 also has a second alignment film 370-2 extending from the pixel 322 and covering the upper electrode 351. The second alignment film 370-2 is also shared with the pixel 322 similarly to the first alignment film 370-1, and the alignment processing direction thereof is the same as that of the alignment film in the pixel 322. The color filter 374 may not be formed in the light control element 324. In this case, as shown in fig. 7, the overcoat 372 may be in contact with the counter substrate 304. The black matrix 376 may be formed in the dimming element 324 so as to overlap the dimming control line 358, for example. Further, although not shown, a transistor electrically connected to the lower electrode 349 and the dimming control line 358 may be provided between the lower electrode 349 and the dimming control line 358, similarly to the pixel 322, and the dimming control signal may be supplied to the lower electrode 349 via the transistor.

The liquid crystal layer 308 is provided between the lower electrode 349 and the upper electrode 351, and the lower electrode 349, the upper electrode 351, the first alignment film 370-1, and the second alignment film 370-2 are sandwiched between the array substrate 302 and the counter substrate 304. As described above, the sealing material 306 forms a single closed shape on the array substrate 302. Therefore, the liquid crystal layer 308 is not provided between the light control element 324 and the pixel 322, and the liquid crystal layer 308 is shared by the light control element 324 and the pixel 322. Similarly to the pixels 322, the light control element 324 may be provided with a spacer 378 for maintaining a distance between the lower electrode 349 and the upper electrode 351.

As described above, the display device 100 includes the pair of linear polarizers 310 and the at least one pair of λ/4 plates 312. The pair of λ/4 wave plates are provided below the array substrate 302 and above the counter substrate 304, respectively, so as to sandwich the dimming element 324, and do not overlap the pixels 322. In other words, the pixels 322 are exposed from the pair of λ/4 plates 312. The slow axes of a pair of lambda/4 wave plates 312 are orthogonal to each other. As described above, the first λ/4 wave plate 312-1 provided below the array substrate 302 is disposed in the opening provided in the resin film 316. Therefore, the resin film 316 is provided so as not to overlap the entire light control element 324 or the lower electrode 349.

The pair of linear polarizers 310 are provided below the array substrate 302 and above the counter substrate 304 so as to sandwich the dimming element 324 and the pair of λ/4 plates 312, respectively. Therefore, in the region where the dimming element 324 is provided, the pair of linear polarizing plates 310 and the pair of λ/4 wave plates 312 overlap each other with the former sandwiching the latter. The pair of linear polarizers 310 is provided so as to overlap the pixels 322, and is shared by the pixels 322 and the light control elements 324. Similarly to the pixel 322, in the light control element 324, the transmission axes of the pair of linear polarizers 310 are also orthogonal to each other. In addition, between the pixel 322 and the dimming cell 324, the directions of the transmission axes of the first linear polarizer 310-1 are identical to each other, and the transmission axes of the second linear polarizer 310-2 are also identical to each other. The slow axes of the pair of lambda/4 wave plates 312 are offset by 45 deg. from the transmission axes of the pair of linear polarizers 310, respectively.

In the light control element 324, the initial alignment of the liquid crystal molecules contained in the liquid crystal layer 308 is also mainly determined by the alignment processing direction of the first alignment film 370-1 and the second alignment film 370-2. In the absence of an electric field, the substrate is oriented in a direction substantially parallel to the surface of the array substrate 302 by the orientation treatment direction. Since the alignment treatment directions of the alignment films 370 are the same as each other between the pixels 322 and the light modulating elements 324, the alignment directions of the liquid crystal molecules are also the same as each other. When a potential difference is applied between the lower electrode 349 and the upper electrode 351, the initial orientation changes. That is, the liquid crystal molecules are raised (tilted) from the surface of the array substrate 302 by an electric field generated between the lower electrode 349 and the upper electrode 351 and substantially perpendicular to the surface of the array substrate 302, and are aligned obliquely or perpendicularly to the surface. The change in the alignment state is controlled by the potential difference between the lower electrode 349 and the upper electrode 351, thereby controlling the light transmittance of the liquid crystal layer 308. As described above, an ECB (Electrically Controlled Birefringence) liquid crystal element is formed in the light control element 324. Therefore, the display device 100 has two liquid crystal elements having different operation modes between the pixel 322 and the light control element 324.

2-4. optical unit

The structures of the light control element 324 and the optical unit 309 in the display region 320 will be described in detail with reference to fig. 8A to 11B. Fig. 8A and 8B are schematic top views of a light control element 324 and a part of a display region 320 surrounding the light control element 324, where the region occupied by the through hole 216 or the pixel 322 is indicated by a dotted line, and the structure above the liquid crystal layer 308 is not shown. Fig. 9A, 10A, and 10B are schematic sectional views along a chain line D-D 'of fig. 8A, and fig. 9B is a schematic sectional view along a chain line E-E' of fig. 8B. In these cross-sectional views, the detailed structure of the pixel circuit and the like provided on the array substrate 302 is omitted.

(1) First optical unit

As shown in fig. 8A and 8B, the resin film 316 is provided with an opening overlapping the photoelectric conversion element 400 or the through hole 216 (see fig. 2), and the first λ/4 wave plate 312-1 is disposed in the opening. In other words, in the first optical unit 309-1, the first λ/4 wave plate 312-1 is surrounded by the resin film 316. The first λ/4 wave plate 312-1 may be in contact with the resin film 316 as shown in fig. 8A and 9A, or the first λ/4 wave plate 312-1 may be isolated from the resin film 316 by a gap 319 as shown in fig. 8B and 9B. Even in the case where the gap 319 exists in the first optical unit 309-1, since the second optical unit 309-2 is disposed on the gap 319, the gap 319 is hardly seen from the outside of the display device 100. Therefore, the influence on the design of the display device 100 can be ignored.

Here, the thickness of the resin film 316 is preferably the same as or substantially the same as that of the first λ/4 wave plate 312-1. That is, in the first optical unit 309-1, the upper surface and the lower surface of the resin film 316 are preferably located on the same plane as the upper surface and the lower surface of the first λ/4 wave plate 312-1, respectively. Alternatively, the thicknesses of the resin film 316 and the first λ/4 wave plate 312-1 are preferably adjusted so that the height difference (distance difference from the surface of the array substrate 302 or the counter substrate 304) between the upper surface and the lower surface of the resin film 316 and the upper surface and the lower surface of the first λ/4 wave plate 312-1 is 0 μm or more and 10 μm or less, 0 μm or more and 5 μm or less, or 0 μm or more and 3 μm or less. With this configuration, the flatness of the first linear polarizer 310-1 or the first λ/4 plate 312-1 can be maintained.

(2) Second optical unit

On the other hand, in the second optical unit 309-2, the second λ/4 plate 312-2 is covered with the second linear polarizer 310-2, and a buffer film 380 is disposed on these members. The buffer film 380 forms a flat upper surface from the display region 320 to the region where the dimming element 324 is disposed. Therefore, the second λ/4 plate 312-2 does not necessarily have to have high flatness, and may have a curved shape. The second λ/4 plate 312-2 may also have an upwardly convex shape or a downwardly convex shape, as shown in FIG. 10A or FIG. 10B, for example. Alternatively, although not shown, a plurality of projections and recesses may be formed on the surface of the second λ/4 plate 312-2. In the case where the second λ/4 plate 312-2 has such a curved shape, the shape of the second λ/4 plate 312-2 is reflected in the second linear polarizer 310-2, and thus, the second linear polarizer 310-2 may also have a curved shape. Specifically, the second linear polarizer 310-2 may have a convex shape upward or downward, or may have a plurality of protrusions and depressions formed on the surface thereof. Similarly, the second adhesive layer 318-2 disposed below the second λ/4 plate 312-2 may have irregularities on the surface thereof or may have a non-uniform thickness on the light control element 324.

The second λ/4 plate 312-2 or the second linear polarizer 310-2, or the second adhesive layer 318-2 has a non-flat configuration, and the second linear polarizer 310-2 is in contact with air without providing the buffer film 380 or the mask plate 382. Accordingly, as shown in fig. 11A, light transmitted through the dimming cell 324 is refracted due to a large refractive index difference between the second linear polarizer 310-2 and the air. If light is randomly refracted at the interface between the second linear polarizer 310-2 and the air, distortion occurs in an image captured when an image pickup device is disposed under the light control device 324 as the photoelectric conversion device 400. In addition, the light emitted from the light adjusting device 324 generates a spot.

Such distortion or generation of a light spot can be prevented by forming the second optical unit 309-2 in a manner having the same configuration as the first optical unit 309-1 (refer to fig. 11B). This is because the λ/4 wave plate 312 is selectively disposed in the opening of the resin film 316, and therefore high flatness can be imparted to the λ/4 wave plate 312 or the linear polarizing plate 310. However, if the gap 319 is located between the second linear polarizer 310-2 and the second λ/4 plate 312-2, light leakage may be caused, resulting in degradation of display quality. In addition, if the gap 319 is visible from the outside, the appearance of the display device 100 is impaired.

However, in the display device 100 of the present embodiment, the buffer film 380 having a flat upper surface is disposed. The buffer film 380 absorbs the curved shape, the unevenness, or the non-flat shape of the second λ/4 plate 312-2 or the second linear polarizer 310-2 to enable a thickness setting to be imparted to the flat upper surface. Therefore, the interface between the buffer film 380 and the air, which generates a large refractive index difference, is flat, and random refraction of light does not occur at the interface. Similarly, when the cover plate 382 is disposed, the random light refraction is suppressed by the flatness of the upper surface of the cover plate 382. The result was. Even if the second λ/4 wave plate 312-2 or the second linear polarizer 310-2 has a curved shape, random refraction of light incident from the outside or light incident from the dimming element 324 side is suppressed. By suppressing the difference in refractive index between the buffer film 380 or the second adhesive layer 318-2, the second λ/4 plate 312-2, and the second adhesive layer 318-2 to 0.15 or less or 0.10 or less, the change in refractive index of light at the interface between these components is reduced, and therefore, this effect can be further increased. Therefore, it is possible to prevent light leakage, distortion of an image obtained by imaging, generation of flare of light obtained from the light control element 324, and the like, and to improve a display device with high design.

3. Movement of

The operation of the light control element 324 will be described with reference to fig. 12A and 12B, and the operation of the pixel 322 will be described with reference to fig. 13A and 13B. In these drawings, the upper electrode 351 and the lower electrode 349 are not shown in the light modulation element 324 in consideration of easy observation. In addition, although the linear polarizer 310 is shown as being separated from the λ/4 plate 312, this is for convenience of illustration only, and these members may be in contact with each other. The dashed arrows shown on the linear polarizer 310 or the λ/4 plate 312 indicate the direction of the respective transmission and slow axes, and the solid arrows indicate the deflection of the light.

3-1. light modulation element

(1) Initial state

Fig. 12A shows a schematic perspective view of the dimming element 324 in an initial state, i.e., an off state. In this state, the alignment of the liquid crystal molecules shown by the ellipses is determined by the alignment control directions of the first and second alignment films 370-1 and 370-2. The alignment treatment directions of the first and second alignment films 370-1 and 370-2 are the same as each other, and thus, in the absence of an electric field, the liquid crystal molecules are aligned in the basic alignment treatment direction.

Here, a case where light travels from the array substrate 302 side (i.e., the first linear polarizer 310-1 side) toward the opposite substrate 304 side (i.e., the second linear polarizer 310-2 side) is considered. Light indicated by a hollow arrow is transmitted through the first linear polarizer 310-1, and becomes linearly polarized light (a) parallel to the transmission axis. When the linearly polarized light (a) is incident from the first λ/4 plate 312-1, the slow axis of the first λ/4 plate 312-1 is shifted from the transmission axis of the first linear polarizer 310-1 by an angle of 45 °, and thus, the phase is shifted by π/2. As a result, the light passing through the first λ/4 plate 312-1 becomes circularly polarized light (b). When the circularly polarized light (b) is transmitted through the liquid crystal layer 308, the circularly polarized light (b) is further delayed by pi due to the anisotropy of the refractive index of the liquid crystal molecules contained in the liquid crystal layer 308, and is converted into circularly polarized light (c) which is reversely rotated. If the circularly polarized light (c) is further incident from the second λ/4 plate 312-2, the transmission axes of the first λ/4 plate 312-1 and the second λ/4 plate 312-2 are in an orthogonal relationship, and thus, are delayed by- π/2. As a result, the phase difference is π compared with the light incident on the first λ/4 wave plate 312-1, becoming linearly polarized light (d). The polarization axis of the linearly polarized light (d) is orthogonal to the polarization axis of the polarized light (a) formed by the first linear polarizer 310-1. The first linear polarizer 310-1 and the second linear polarizer 310-2 are in a relationship of orthogonal polarization to each other, and thus, the linearly polarized light (d) can be transmitted through the second linear polarizer 310-2. Similarly, when external light travels from the counter substrate 304 to the array substrate 302, the first linear polarizer 310-1 can be transmitted therethrough. Therefore, the light passes through the light control element 324, and the light control element 324 functions as a so-called normally white element.

(2) Drive the

When a potential difference is applied between the lower electrode 349 and the upper electrode 351, that is, fig. 12B shows a schematic perspective view of the light control element 324 in the activated state. When the potential difference exceeds the threshold voltage, the liquid crystal molecules start rising with respect to the surface of the array substrate 302, and the rising angle increases as the potential difference increases. Accordingly, the birefringence becomes smaller with respect to light incident on the liquid crystal molecules. When the birefringence is 0, the polarization characteristic of the circularly polarized light (b) generated by transmission through the first λ/4 plate 312-1 is maintained, and the circularly polarized light enters the second linear polarizer 310-2. The circularly polarized light (c) is converted into linearly polarized light (d) by the second linear polarizer 310-2, but the polarization axis at this time is the same as the polarization axis of the linearly polarized light (a) formed by the first linear polarizer 310-1 and is orthogonal to the transmission axis of the second linear polarizer 310-2. Therefore, the light incident to the first linear polarizer 310-1 cannot transmit the dimming cell 324. The light incident on the second linear polarizer 310-2 does not transmit the first linear polarizer 310-1 in the same manner.

The birefringence of the liquid crystal molecules with respect to light incident on the liquid crystal molecules is controlled by the rising angle of the liquid crystal molecules, which is determined by the potential difference applied between the upper electrode 351 and the lower electrode 349. Therefore, by controlling the potential difference using the dimming control signal, the light transmittance of the dimming element 324 can be adjusted.

As described above, the through-hole 216 provided in the light guide plate 204 or the reflection plate 202 is located in the region where the light control element 324 is provided. Therefore, when the light control element is in the off state (i.e., normally white), external light can be transmitted through the light control element 324, and therefore, sensing, imaging, and the like of the external light can be performed by the photoelectric conversion element 400 disposed in or below the through hole 216. On the other hand, by driving the light control element 324 and controlling the potential difference between the upper electrode 351 and the lower electrode 349, the transmittance thereof can be adjusted, and the light control element 324 can be made to function as a light reduction filter (ND (Neutral Density) filter) or a shutter. When functioning as a shutter, since the external light reflected by the photoelectric conversion element 400 can be shielded, adverse effects on the display formed by the pixels 322 can be prevented.

As described above, in the light control element 324 of the display device 100, the lower electrode 349 does not need to be provided with the slit or the notch in the lower electrode 349, and has the same thickness in substantially the entire light control element 324, and is disposed so as to cover the entire through-hole 216 or the entire light receiving surface of the photoelectric conversion element 400. Therefore, the occurrence of the refractive index distribution due to the presence of the slit or the notch can be avoided. Further, an opening overlapping the light control element 324 is provided in the resin film 316, and the first λ/4 wave plate 312-1 is disposed in the opening, thereby securing high flatness of the surface of the first λ/4 wave plate 312-1 or the first linear polarizer 310-1. On the other hand, the buffer film 380 having a flat upper surface is formed on the second linear polarizer 310-2, and thus random light refraction due to the shape of the second λ/4 plate 312-2 is prevented. Therefore, the light transmitted through the dimming element 324 is not adversely affected. As a result, for example, when an image pickup device is used as the photoelectric conversion device 400, a high-quality image can be obtained without causing adverse effects such as streaks, flare, and distortion in the captured image.

3-2. pixel

(1) Initial state

Fig. 13A is a schematic perspective view showing the pixel 322 in the off state. In this state, the alignment of the liquid crystal molecules is determined by the alignment characteristics of the first alignment film 370-1 and the second alignment film 370-2, as in the light control element 324. The alignment treatment directions of the first and second alignment films 370-1 and 370-2 are the same as each other, and thus, in the absence of an electric field, the liquid crystal molecules are aligned in the basic alignment treatment direction.

Here, a case where light from the backlight unit 200 enters from the first linear polarizer 310-1 side and travels toward the second linear polarizer 310-2 side is considered. Light from the backlight unit 200, which is indicated by hollow arrows, is transmitted through the first linear polarizer 310-1, becoming linearly polarized light (a) parallel to the transmission axis. Since the λ/4 wave plate 312 is not provided in the pixel 322, the linearly polarized light (a) is incident on the liquid crystal layer 308 thereafter. When the alignment treatment is performed on the alignment film 370 such that the alignment treatment direction is perpendicular to the transmission axis of the first linear polarizer 310-1, the polarization axis of the linearly polarized light (a) is substantially perpendicular to the alignment direction of the liquid crystal molecules. Therefore, birefringence does not occur, and light does not generate a retardation. As a result, the linearly polarized light (a) enters the second linearly polarizing plate 310-2 while maintaining substantially the polarization axis and intensity. However, the transmission axis of the second linear polarizer 310-2 is orthogonal to the first linear polarizer 310-1, and thus, light (b) incident to the second linear polarizer 310-2 is absorbed by the second linear polarizer 310-2 and does not exit the pixel 322. Therefore, in the off state, the pixel 322 becomes so-called normally black.

(2) Drive the

Fig. 11B shows a schematic perspective view of the pixel 322 in a case where a potential difference is applied between the pixel electrode 350 and the common electrode 348, that is, in an on state. An electric field substantially parallel to the surface of the array substrate 302 is generated by the potential difference, and the liquid crystal molecules rotate in a plane parallel to the surface of the array substrate 302 due to the anisotropy of the dielectric constants of the liquid crystal molecules. Therefore, the polarization axis of the linearly polarized light (a) incident on the liquid crystal layer 308 is shifted from the alignment direction of the liquid crystal molecules, and a retardation is generated in the light incident on the liquid crystal layer 308. Here, in the display device 100, the thickness of the liquid crystal layer 308 is controlled according to the refractive indices of the liquid crystal molecules in the major axis direction and the minor axis direction so that the retardation becomes substantially pi. Therefore, the light passing through the liquid crystal layer 308 becomes linearly polarized light (b) having a polarization axis rotated from the linearly polarized light (a). When the alignment of the liquid crystal molecules is rotated by 90 °, the polarization axis of the linearly polarized light (b) is orthogonal to the polarization axis of the linearly polarized light (a). In addition, the first linear polarizer 310-1 and the second linear polarizer 310-2 are in a cross-polarization relationship. Accordingly, the linearly polarized light emitted from the liquid crystal layer 308 can be transmitted through the second linearly polarizing plate 310-2.

The amount of light to be extracted is determined by the angle of rotation of the liquid crystal molecules, and this can be controlled by the potential difference between the pixel electrode 350 and the common electrode 348 based on the potential of the video signal. Therefore, by controlling the potential difference, the pixel is tuned. Further, since the color filters 374 having different optical characteristics are provided for each pixel as described above, the gradation can be controlled for each color, and full-color display can be performed on the display region 320.

As described above, in the display device 100, the pixels 322 provided in the display region 320 are normally black, and therefore, display with high contrast can be achieved. In addition, since the FFS liquid crystal is formed in the pixel 322, display with excellent viewing angle characteristics can be performed. This enables high-quality full-color display in the display device 100.

Since the light control device 324 is disposed so as to be surrounded by the pixels 322, the photoelectric conversion device 400 such as an image pickup device can be provided so as to overlap the display region 320. Therefore, the photoelectric conversion element 400 does not need to be disposed in the frame, the frame region can be reduced or eliminated, and the facing area of the display region 320 occupying the entire display device can be increased. As a result, an electronic device having a large display area 320 and excellent design can be provided. Further, since the light transmittance of the light control element 324 can be controlled, the amount of light incident on the photoelectric conversion element 400 can be appropriately adjusted without causing a reduction in display quality by the light control element 324.

4. Modification example

The display device 100 may include a pair of 1/2 wave-blocking plates (hereinafter referred to as λ/2 wave plates) 314 instead of the pair of λ/4 wave plates 312. The structure and operation in this case will be described with reference to fig. 14A and 14B. Fig. 14A and 14B are schematic perspective views of the display device 100 in the initial state and in the driving state, respectively, and correspond to fig. 12A and 12B, respectively.

The pair of λ/2 wave plates 314 are provided so as to sandwich the dimming element 324, and are sandwiched by the pair of linear polarizers 310. The λ/2 plate (first λ/2 plate 314-1) disposed on the array substrate 302 side is disposed with its slow axis shifted by 22.5 ° from the slow axis of the first linear polarizer 310-1. Similarly, the λ/2 wave plate (second λ/2 wave plate 314-2) disposed on the counter substrate 304 side is also disposed with its slow axis shifted by 22.5 ° from the slow axis of the second linear polarizer 310-2. Therefore, the pair of λ/2 wave plates 314 are orthogonal to each other in slow axis, and the pair of linear polarizers 310 are also orthogonal in polarization to each other.

4-1. initial state

In the off state, the liquid crystal molecules are aligned substantially in the alignment treatment direction (fig. 14A) as in the case of using the pair of λ/4 wave plates 312 (fig. 12A). Light entering from the first linear polarizer 310-1 side is transmitted through the first linear polarizer 310-1, and becomes linearly polarized light (a) parallel to the transmission axis. The linearly polarized light (a) is then incident on the first λ/2 plate 314-1 with a phase shift of π, but the slow axis of the first λ/2 plate 314-1 is shifted from the transmission axis of the first linearly polarized plate 310-1 by an angle of 25.5 °, so that the polarization axis of the linearly polarized light (a) passing through the first λ/2 plate 314-1 has a phase difference of π/2 with respect to the transmission axis of the first linearly polarized plate 310-1, i.e., becomes a linearly polarized light (b) shifted by 45 °. The linearly polarized light (b) passes through the liquid crystal layer 308 to generate a retardation. Here, in the display device 100, the thickness of the liquid crystal layer 308 is controlled in accordance with the refractive indices of the liquid crystal molecules in the major axis direction and the minor axis direction so that the retardation becomes substantially pi. Therefore, the linearly polarized light (b) passes through the liquid crystal layer 308, and the polarization axis is further shifted by 90 °, thereby becoming linearly polarized light (c). The linearly polarized light (c) further enters the second λ/2 plate 314-2 to generate a phase difference of π, but the slow axis of the second λ/2 plate 314-2 is deviated from the transmission axis of the second linear polarizer 310-2 by 25.5 °, thereby imparting a phase difference of π/2. As a result, the polarization axis is shifted by 45 °, and the linear polarization plate becomes a linear polarization plate (d) having a polarization axis orthogonal to the transmission axis of the first linear polarization plate 310-1. The polarization axis of the linearly polarized light (d) is orthogonal to the transmission axis of the second linear polarizer 310-2, and thus, light cannot transmit the second linear polarizer 310-2. Therefore, in the off state, the light-adjusting element 324 is so-called normally black.

4-2. drive

When the potential difference applied between the lower electrode 349 and the upper electrode 351 exceeds the threshold voltage, the liquid crystal molecules start to rise with respect to the surface of the array substrate 302, and the rising angle increases as the potential difference increases. Accordingly, the birefringence becomes smaller with respect to light incident on the liquid crystal molecules. When the birefringence is 0, the polarization characteristics of the linearly polarized light (b) generated by transmitting through the first λ/2 wave plate 314-1 are maintained, and the linearly polarized light (c) enters the second λ/2 wave plate 314-2. The linearly polarized light (c) is converted into linearly polarized light (d) by the second λ/2 plate 314-2, but the slow axis of the second λ/2 plate 314-2 is shifted from the transmission axis of the second linear polarizer 310-2 by 22.5 °, and thus the polarization axis is the same as that of the second linear polarizer 310-2. Accordingly, the linearly polarized light (d) can transmit the second linearly polarizing plate 310-2. The light incident from the second linear polarizer 310-2 can transmit the first linear polarizer 310-1 in the same manner.

The birefringence of the liquid crystal molecules with respect to light incident on the liquid crystal molecules is controlled by the rising angle of the liquid crystal molecules, which is determined by the potential difference applied between the upper electrode 351 and the lower electrode 349. Therefore, by controlling the potential difference using the dimming control signal, the light transmittance of the dimming element 324 can be adjusted. For example, when the light control element is in an off state (i.e., normally black), since the light control element 324 is not transparent to external light, the external light reflected by the photoelectric conversion element 400 can be shielded, and adverse effects on the display formed by the pixels 322 can be prevented. On the other hand, since the light control element 324 is driven to control the potential difference between the upper electrode 351 and the lower electrode 349 and the transmittance thereof can be adjusted, the light control element 324 can be made to function as an ND filter or a shutter. Therefore, the potential difference between the upper electrode 351 and the lower electrode 349 is appropriately controlled according to the external environment, and the amount of light incident on the photoelectric conversion element 400 can be optimized.

Further, since the single lower electrode 349 is disposed so as to cover the entire through hole 216 or the entire light receiving surface of the photoelectric conversion element 400, occurrence of a refractive index distribution can be avoided. As described above, the opening overlapping the light control element 324 is provided in the resin film 316, and the first λ/4 wave plate 312-1 is disposed in the opening, thereby securing high flatness of the surface of the first λ/4 wave plate 312-1 or the first linear polarizer 310-1. On the other hand, the buffer film 380 is disposed on the second linear polarizer 310-2, thereby preventing random light refraction due to the shape of the second λ/4 plate 312-2 or the second linear polarizer 310-2. Therefore, the light passing through the light control device 324 is not refracted irregularly, and a high-quality image can be obtained without giving adverse effects such as streaks, flare, distortion, and the like to the image captured by the photoelectric conversion device 400.

< embodiment 2 >

In this embodiment, an example of a method for manufacturing the display device 100 having the structure described in embodiment 1 will be described. Description may be omitted for the same or similar structure as that described in embodiment 1.

Fig. 15A to 20 are schematic cross-sectional views illustrating a method of manufacturing the display device 100. In each of these figures, the left side shows a portion of the pixel 322 and the right side shows a portion of the dimming element 324.

1. Array substrate

Fig. 15A is a schematic view of the array substrate 302 up to the interlayer insulating film 364. This structure can be formed using a known method or material, and therefore, description thereof is omitted.

The interlayer insulating film 364 is etched to form an opening reaching the semiconductor film 352, and a metal film is formed so as to cover the opening. The metal film is formed by laminating films made of molybdenum or a metal such as tungsten, titanium, or aluminum by a sputtering method, a Chemical Vapor Deposition (CVD) method, or the like. Thereafter, the metal film is etched to form the video signal line 342, the drain electrode 354, and the light control line 358 (fig. 15B). Thereby forming a transistor 346. As described above, a part of the video signal line 342 functions as a source electrode of the transistor 346.

Thereafter, a planarization film 366 is formed so as to cover the transistor 346 or the dimming control line 358 (fig. 15C). The planarizing film 366 is formed by applying a precursor of the polymer described in embodiment 1 by a wet film forming method such as a spin coating method, a dip coating method, an ink jet printing method, or a printing method, and then curing the applied precursor.

Thereafter, the common electrode 348 is formed on the planarization film 366 (fig. 15C). The common electrode 348 is configured to transmit visible light. Therefore, the common electrode 348 may be formed by a sputtering method or the like using a conductive oxide that exhibits transparency to visible light, such as indium-tin mixed oxide (ITO) or indium-zinc mixed oxide (IZO). Although not shown, the power supply line 344 is formed after the common electrode 348 is formed. The power supply line 344 is formed by stacking films including the above-described metals by a sputtering method, a CVD method, or the like. Although not shown, when the FFS liquid crystal is formed in the light control element 324, the lower electrode 349 may be formed simultaneously with the common electrode 348. Therefore, in this case, the common electrode 348 and the lower electrode 349 are located in the same layer, having the same composition or thickness.

Thereafter, an inter-electrode insulating film 368 is formed so as to cover the common electrode 348 and the dimming control line 358 (fig. 16A). The inter-electrode insulating film 368 includes the above-described silicon-containing inorganic compound, and is formed by a CVD method or a sputtering method. Next, the interelectrode insulating film 368 and the planarization film 366 are etched to form

openings

357 and 356 reaching the drain electrode 354 and the dimming control line 358, respectively (fig. 16A).

Thereafter, the pixel electrode 350 and the lower electrode 349 are formed in contact with the drain electrode 354 and the dimming control line 358, respectively (fig. 16B). These electrodes are also preferably highly transparent to visible light, and therefore, may be formed by sputtering or the like using a conductive oxide exhibiting transparency, such as ITO or IZO. Since the pixel electrode 350 and the lower electrode 349 can be formed at the same time, they can have the same composition and thickness in the same layer. Although not shown, when the FFS liquid crystal is formed in the light control element 324, the upper electrode 351 may be formed simultaneously with the pixel electrode 350. Therefore, in this case, the pixel electrode 350 and the upper electrode 351 are located in the same layer, and can have the same composition or thickness.

Thereafter, a first alignment film 370-1 is formed so as to cover the pixel electrode 350 and the lower electrode 349 (fig. 16B). For example, the first alignment film 370-1 can be formed by applying a polyimide precursor by a wet film formation method, hardening the polyimide precursor, and then performing a rubbing treatment. The rubbing treatment may be performed by a known method.

2. Opposed substrate

A color filter 374 or a black matrix 376 is formed on the counter substrate 304 (fig. 17A). In the pixel 322, the black matrix 376 is provided so as to cover the transistor 346, the video signal line 342, the gate line 340, and the like, and is provided so as to cover the dimming control line 358 in the dimming element 324. The color filter 374 may not be provided in the dimming element 324. When the overcoat 372 is formed, it is provided so as to cover the color filter 374 or the black matrix 376 (fig. 17B). The color filter 374, the black matrix 376, and the overcoat 372 may be formed by a known method or material, and thus detailed description thereof will be omitted.

Thereafter, the upper electrode 351 of the light control element 324 is formed (fig. 17C). The upper electrode 351 can be formed by the same method as the lower electrode 349, the common electrode 348, and the pixel electrode 350. Thereafter, the second alignment film 370-2 is formed so as to cover the color filter 374, the black matrix 376, and the upper electrode 351. The second alignment film 370-2 may be formed by the same method as the first alignment film 370-1. Spacers 378 formed into an arbitrary structure by applying a known method or material are provided on the second alignment film 370-2 (fig. 17C). The spacers 378 may also be formed on the first alignment film 370-1 disposed on the array substrate 302.

3. Unit set

Thereafter, a liquid crystal layer 308 is formed. Specifically, a sealing material 306 is applied to one of the array substrate 302 and the counter substrate 304, and a liquid crystal layer 308 is dropped in a region formed by the sealing material 306. Thereafter, the pixel electrode 350 or the common electrode 348, the lower electrode 349, and the upper electrode 351 are arranged such that the other of the array substrate 302 and the counter substrate 304 is sandwiched between the array substrate 302 and the counter substrate 304 over the liquid crystal layer 308 and the sealing material 306, and the sealing material 306 is cured. At this time, the pixel electrode 350 and the common electrode 348 are exposed from the upper electrode 351 without overlapping the upper electrode 351. Thereby, the array substrate 302 and the counter substrate 304 are bonded and fixed (fig. 18). Alternatively, the array substrate 302 and the counter substrate 304 are bonded in advance using the sealing material 306. In this case, the sealing member 306 is not formed in a closed shape, and is formed so as to be separated into two parts. After the sealing material 306 is hardened, a liquid crystal layer 308 is injected from between the two separated sealing materials 306, and thereafter, the sealing material 306 is further applied between the sealing materials 306 and hardened. Thus, the sealing material 306 gives a single closed shape. Further, in the case where the spacers 378 are not formed, granular spacers may be mixed into the liquid crystal layer 308.

Thereafter, the first optical unit 309-1 and the second optical unit 309-2 are fixed to the lower surface of the array substrate 302 and the upper surface of the opposite substrate 304, respectively, using the first adhesive layer 318-1 and the second adhesive layer 318-2 (fig. 19). Specifically, a laminate including the first adhesive layer 318-1, the resin film 316 on the first adhesive layer 318-1, the first λ/4 plate 312-1 positioned on the adhesive layer 318 and disposed at the opening of the resin film 316, and the first linear polarizer 310-1 laminated on the resin film 316 and the first λ/4 plate 312-1 is fixed so that the first adhesive layer 318-1 is in contact with the array substrate 302. On the other hand, a laminate including the second adhesive layer 318-2, the second λ/4 plate 312-2 on the second adhesive layer 318-2, and the second linear polarizer 310-2 covering the second λ/4 plate 312-2 is formed so that the second adhesive layer 318-2 is in contact with the counter substrate 304. The pair of optical units 309 are fixed so that the pair of λ/4 wave plates 312 overlap the dimming element 324.

Thereafter, the buffer film 380 is formed. Specifically, the precursor of the resin or polymer described in embodiment 1 is coated on the second linear polarizer 310-2. The coating may be performed by a method such as an ink jet printing method, a printing method, or a spin coating method. Alternatively, the resin or polymer precursor may be disposed using a sheet-like resist. Thereafter, the precursor is heated or irradiated with light to cure the precursor, whereby the buffer film 380 is formed (fig. 20). In the case of forming the mask plate 382, after the precursor is formed, the opposite substrate 304 is disposed, and the mask plate 382 is fixed by heating the precursor or irradiating the precursor with light to cure the precursor. At this time, the counter substrate 304 may be heated or irradiated with light while applying pressure to compress the precursor. Through this step, the cover plate 382 is fixed while the buffer film 380 having a flat upper surface is formed (fig. 20).

When the optical units 309 are fixed, pressure may be applied to the optical units 309 so as to compress the adhesive layers 318. At this time, the second λ/4 plate 312-2 or the second linear polarizer 310-2 thereon is sometimes bent by the magnitude of the pressure, the time of applying the pressure, or the like. However, by providing the buffer film 380 or providing the cover plate 382 through the buffer film 380, random light refraction due to the curved shape of the second λ/4 plate 312-2 or the second linear polarizer 310-2 can be prevented.

The display module 300 is formed through the above processes. The display device 100 can be manufactured by disposing and fixing the display module 300 on the backlight unit 200 by a known method.

By applying the embodiments of the present invention, a display device having a small frame region and a wide display surface can be provided. In this display device, various photoelectric conversion elements can be mounted so as to overlap the display surface, and therefore, the embodiment of the present invention can provide a high degree of freedom in design of the display device. Further, by controlling the transmittance of the light control element provided in the display surface so as to overlap with the photoelectric conversion element, the amount of light incident from the photoelectric conversion element can be controlled without causing a reduction in display quality.

Further, since the single lower electrode 349 is disposed so as to cover the entire through hole 216 or the entire light receiving surface of the photoelectric conversion element 400, the occurrence of the refractive index distribution can be avoided. Further, since the optical unit having the above-described structure can prevent adverse effects on external light incident on the light control element 324, a high-quality image can be obtained through the display region 320 without adverse effects such as streaks, flare, and distortion on an image captured by the photoelectric conversion element 400.

Even if the operation and effect is different from the operation and effect obtained by the aspects of the above embodiments, it is needless to say that the operation and effect which is clearly obtained from the description of the present specification or which can be easily predicted by a person skilled in the art is also understood to be brought about by the present invention.

Claims

1. A display device is provided with:

a first optical unit including a first linear polarizer, a resin film on the first linear polarizer and having an opening, and a first wave-blocking sheet in the opening;

an array substrate on the first optical unit and having a pixel electrode;

a liquid crystal layer on the array substrate;

an opposite substrate on the liquid crystal layer;

a second optical unit on the counter substrate, the second optical unit having a second wave-resistance sheet overlapping the first wave-resistance sheet and a second linear polarizer on the second wave-resistance sheet; and

a buffer film on the second optical unit.

2. The display device according to claim 1,

a cover plate is also arranged on the buffer film.

3. The display device according to claim 1,

the resin film is in contact with the first wave-resistance sheet.

4. The display device according to claim 1,

the resin film is isolated from the first wave-resistance sheet.

5. The display device according to claim 1,

the lower surface of the resin film and the lower surface of the first wave resistance sheet are located on the same plane.

6. The display device according to claim 1,

the second wave resistance plate has a curved shape.

7. The display device according to claim 6,

the second wave resistance sheet has an upwardly convex or downwardly convex shape.

8. The display device according to claim 6,

the second linear polarizer has a curved shape.

9. The display device according to claim 6,

the upper surface of the buffer film is above the second wave-resistance sheet and is flat.

10. The display device according to claim 1,

further comprising at least one pixel including the pixel electrode, the counter electrode, and the liquid crystal layer, and a light control element including a pair of electrodes and the liquid crystal layer,

the at least one pixel overlaps the resin film, the first linear polarizing plate, and the second linear polarizing plate and is exposed from the second wave-blocking plate,

the light adjusting element overlaps the first linear polarizer, the first wave-blocking plate, the second wave-blocking plate, and the second linear polarizer.

11. The display device according to claim 10,

the at least one pixel includes a plurality of pixels surrounding the dimming element.

12. The display device according to claim 1,

also provided with a backlight having a light guide plate,

the light guide plate has a through hole overlapping the first and second wave-resistance sheets.

13. A display device is provided with:

a first linear polarizer;

a first wave-drag sheet on the first linear polarizer;

a light control element which is located on the first wave resistor and is composed of a pair of electrodes and a liquid crystal layer;

a second wave resistance sheet having a curved shape, which is located on the dimming element, overlapping the first wave resistance sheet;

a second linear polarizer on the second wave-resistance sheet and covering the second wave-resistance sheet; and

a buffer film on the second linear polarizer having a flat upper surface above the second wave-blocker.

14. The display device according to claim 13,

a cover plate is also arranged on the buffer film.

15. The display device according to claim 13,

the liquid crystal display device further includes a plurality of pixels surrounding the light adjusting element, and the plurality of pixels are sandwiched between the first linear polarizing plate and the second linear polarizing plate and exposed from the second wave-blocking plate.

16. The display device according to claim 15,

a resin film is further provided between the first linear polarizing plate and the plurality of pixels,

the resin film has an opening formed therein,

the first wave drag sheet is positioned in the opening.

17. The display device according to claim 16,

the resin film is in contact with the first wave-resistance sheet.

18. The display device according to claim 16,

the resin film is isolated from the first wave-resistance sheet.

19. The display device according to claim 15,

the liquid crystal layer is sandwiched by the pair of electrodes in the light adjusting element,

each of the plurality of pixels is configured by a pixel electrode, a common electrode, and the liquid crystal layer on the pixel electrode and the common electrode.

20. The display device according to claim 13,

also provided with a backlight having a light guide plate,

the light guide plate has a through hole overlapping the light adjusting element.