WO2005106573A1

WO2005106573A1 - Liquid crystal display and process for fabricating the same

Info

Publication number: WO2005106573A1
Application number: PCT/JP2004/006300
Authority: WO
Inventors: Masaya Nakayama; Masaru Kinoshita
Original assignee: Fuji Photo Film Co., Ltd.
Priority date: 2004-04-30
Filing date: 2004-04-30
Publication date: 2005-11-10
Also published as: TWI251700B; TW200535516A

Abstract

An organic EL illuminator (3) comprises a transparent electrode as an anode (22) formed on the surface of a third transparent substrate (21), an auxiliary electrode (23) patterned on the anode (22), an insulating film (24) formed to cover the upper surface of the auxiliary electrode (23), and an organic EL layer (25) and a cathode (26) sequentially formed on the anode (22) to cover the auxiliary electrode (23) and the insulating film (24). With such a structure, low power consumption of the organic EL illuminator (3) is realized by enhancing emission efficiency, and a highly-reliable low power consumption liquid crystal display capable of emitting light cleanly and uniformly can be realized by preventing short circuit or leakage between the auxiliary electrode (23) and the anode (22).

Description

Description Liquid crystal display device and manufacturing method thereof

The present invention relates to a liquid crystal display device using a so-called organic EL lighting device as a backlight of a liquid crystal cell, and a method for manufacturing the same.

Background art

Liquid crystal display devices are used in monitors, notebook computers, mobile phones, televisions, etc., and are widely used as representatives of flat panel displays. Since a liquid crystal cell is a non-light emitting element that does not emit light, a light source called a backlight that normally illuminates the liquid crystal cell from the backside is required. The most commonly used backlight is a so-called light guide system comprising a fluorescent tube and a light guide for turning light emitted from the fluorescent tube into a surface light source. . However, this light guide method requires a certain thickness (about three times that of the liquid crystal cell) to obtain uniform surface light emission, making it difficult to reduce the overall thickness of the liquid crystal display device. Was. Accordingly, attempts to use a surface emitting element light source as a backlight have been actively made in recent years. In particular, an organic EL lighting device using an organic EL device as a surface light emitting device is very effective as a backlight for a liquid crystal display device because it can be made very thin. '

FIG. 9 is a schematic cross-sectional view showing one configuration example of a conventional organic EL lighting device.

In this organic EL lighting device, an anode 102 made of a transparent electrode such as ITO is formed on a transparent substrate 101 made of glass or the like, and an organic EL layer 103 containing an organic luminescent material is further formed thereon. Cathodes 104 made of a metal having a small work function such as L i, Mg and A 1 are sequentially laminated, and a sealing plate 105 made of glass or the like is further provided for protection from the outside air such as moisture and oxygen. It is bonded and sealed in a dry nitrogen atmosphere using a transparent substrate 101 and an adhesive 106. By using such an organic EL lighting device as a backlight for a liquid crystal display device, the backlight can be made thinner, and the overall thickness of the liquid crystal display device can be reduced. However, in recent years, there has been an increasing demand for a larger area of the liquid crystal display device, and it has become necessary to increase the area of the backlight organic EL lighting device. However, as the area of the organic EL lighting device increased, the effect of electrode resistance became more significant. In particular, non-metallic materials such as ITO used for the anode transparent electrode have low resistivity, which increases the effect of the voltage drop, causing problems such as uneven light emission of the organic EL lighting device and heat generation at the transparent electrode. Is increased.

To solve such a problem, it is necessary to reduce the resistance of the transparent electrode. Therefore, Patent Document 1 discloses a technique for reducing the resistance of a transparent electrode by using a low-resistance auxiliary electrode made of metal. However, since the metal has light impermeability in the visible light castle, the metal is shielded from light by the luminescent capture electrode, and the brightness of the organic EL lighting device is reduced. A solution to such a problem is disclosed in Patent Document 2. This is a method in which an auxiliary electrode is provided in a portion of the liquid crystal display device other than the region where the display pixel electrode is formed, that is, in a portion that does not directly affect display. With this configuration, since the auxiliary electrode is provided at the light-impermeable portion of the liquid crystal display device, the decrease in brightness due to the light blocking of the auxiliary electrode is effectively eliminated in the entire liquid crystal display device.

However, even in the configuration disclosed in Patent Document 2, current also flows through the organic EL layer in the light-impermeable portion on the trapping electrode, and the luminous efficiency of the organic EL lighting device is reduced. In addition, the metal material usually has poor surface flatness compared to ITO, so that a short circuit may occur between the auxiliary electrode and the cathode or a leak may occur between the two.

Patent Document 1 Japanese Patent Application Laid-Open No. 2000-2000

Patent Document 2 Japanese Patent Application Laid-Open No. 2000-15056 633

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and achieves low power consumption by improving the luminous efficiency of an organic EL lighting device, and generates a short circuit between an auxiliary electrode and a second electrode. It is an object of the present invention to provide a liquid crystal display device having an organic EL lighting device with low power consumption and high reliability and capable of emitting clean uniform light, and a method of manufacturing the same.

Disclosure of the invention

As a result of intensive studies, the present inventors have arrived at various aspects of the invention described below. A liquid crystal display device according to the present invention includes a liquid crystal cell having a liquid crystal layer, a plurality of display pixels formed thereon, and an organic EL layer for illuminating the liquid crystal cell from behind a first electrode. An illuminating means sandwiched between an electrode and a second electrode which is a metal electrode, arranged so as to face the liquid crystal cell on the first electrode side, and matching with a non-formation region of the display pixel A trapping electrode provided at a position and electrically connected to the first electrode, and a trapping electrode provided at a position matching a region where the auxiliary electrode is formed on the surface of the organic EL layer; And an insulating film for at least partially insulating the auxiliary electrode.

Here, it is preferable that the insulating film is formed on the first electrode so as to cover at least an upper surface of the auxiliary electrode.

Further, the insulating film may be formed on the first electrode so as to cover the entire surface of the trapping electrode.

The method for manufacturing a liquid crystal display device according to the present invention includes a step of sequentially forming a first electrode, which is a transparent electrode, an electrode material and an insulating resin on a surface of a transparent substrate, and processing the insulating resin by lithography. Forming an electrode-shaped insulating film; processing the electrode material using the insulating film as a mask to pattern an auxiliary electrode; and forming the auxiliary electrode on the first electrode via the insulating film. A step of sequentially forming an organic EL layer and a second electrode which is a metal electrode so as to cover the electrode; anda liquid crystal cell having a liquid crystal layer and a plurality of display pixels formed thereon and a back surface of the transparent substrate. Arranging the auxiliary electrodes so as to face each other so as to be located at a position matching the non-formation region of the display pixel. Another aspect of the method for manufacturing a liquid crystal display device of the present invention includes a step of sequentially forming a first electrode, which is a transparent electrode, and an electrode material on a surface of a transparent substrate; Forming an insulating material on the first electrode so as to cover the auxiliary electrode; processing the insulating material to cover the auxiliary electrode according to the shape of the auxiliary electrode Forming a pattern, and sequentially forming an organic EL layer and a second electrode which is a metal electrode on the first electrode so as to cover the auxiliary electrode via the insulating film. A step of arranging a liquid crystal cell having a plurality of display pixels formed thereon and a rear surface of the transparent substrate so as to face each other so that the trapping electrode is located at a position matching a region where the display pixels are not formed. And Another aspect of the method for manufacturing a liquid crystal display device of the present invention includes a step of patterning an auxiliary electrode on a surface of a transparent substrate, and a first step of forming a transparent electrode on the transparent substrate so as to cover the auxiliary electrode. A step of sequentially forming an electrode and an insulating resin; and performing lithography by irradiating from the back surface of the transparent substrate, processing the insulating resin into a shape following the auxiliary electrode using the auxiliary electrode as a mask, Forming an insulating film on a portion of the second electrode, the second electrode being an organic EL layer and a metal electrode on the first electrode so as to cover the insulating film. Forming a plurality of display pixels each having a liquid crystal layer and a rear surface of the transparent substrate, a portion where the trapping electrode is aligned with a region where the display pixels are not formed. Opposed to be located at And a degree.

Brief Description of Drawings

1A and 1B are schematic plan views showing the configuration of the liquid crystal display device according to the first embodiment.

FIG. 1C is a schematic cross-sectional view along the line II of FIG. 1B.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of an organic EL lighting device that is a component of the liquid crystal display device according to the first embodiment.

FIG. 3 is a schematic cross-sectional view showing the configuration of a comparative example (conventional example) of an organic EL lighting device used for a backlight of a liquid crystal display device.

4A to 4F are schematic cross-sectional views illustrating a method for manufacturing the liquid crystal display device according to the first embodiment in the order of steps.

FIG. 5 is a schematic cross-sectional view illustrating a configuration of an organic EL lighting device that is a component of a liquid crystal display device according to a modification of the first embodiment. ·

6A to 6G are schematic cross-sectional views illustrating a method for manufacturing a liquid crystal display according to a modification of the first embodiment in the order of steps.

FIG. 7 is a schematic cross-sectional view illustrating a configuration of an organic EL lighting device that is a component of the liquid crystal display device according to the second embodiment.

8A to 8G are schematic cross-sectional views illustrating a method for manufacturing the liquid crystal display device according to the second embodiment in the order of steps.

FIG. 9 is a schematic cross-sectional view showing one configuration example of a conventional organic EL lighting device. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments to which the present invention is applied will be described in detail with reference to the drawings.

1st Embodiment 1

(Configuration of liquid crystal display device)

1A and 1B are schematic plan views showing the configuration of the liquid crystal display device according to the present embodiment, and FIG. 1C is a schematic cross-sectional view along the line I-I in FIG. 1B. FIG. 2 is a schematic cross-sectional view illustrating a configuration of an organic EL lighting device that is a component of the liquid crystal display device according to the present embodiment.

As shown in FIG. 1C, the liquid crystal display device 1 of the present embodiment includes a liquid crystal cell 2 as a display means and an organic EL lighting device 3 used as a backlight of the liquid crystal cell 2. ing.

The liquid crystal cell 2 has a plurality of strip-shaped transparent electrodes 11 made of ITO or the like formed on the surface thereof, and an alignment film 12 formed on the transparent electrodes 11.

1 transparent substrate 13 and a plurality of strip-shaped transparent electrodes 14 made of ITO or the like on the surface and orthogonal to the transparent electrode 11, and an alignment film 15 is formed on the transparent electrode 14. A liquid crystal in which alignment films 12 and 15 are sandwiched between a second transparent substrate 16 made of glass or the like and a first transparent substrate 13 and a second transparent substrate 16. A polarizing plate 18 on the back surface of the first transparent substrate 13, and a second transparent substrate

A polarizing plate 19 is arranged on the back surface of 16 respectively. In this liquid crystal cell 2, as shown in FIGS. 1A and 1B, when the transparent electrode 11 and the transparent electrode 14 are orthogonal to each other, the transparent electrode 11 and the transparent electrode 14 overlap each other via the liquid crystal layer 1.7 and the like. A plurality of display pixel electrodes (apertures) 10 are formed from the portions indicated by.

Although the liquid crystal cell is described as a simple matrix type in the text, an active matrix type liquid crystal cell provided with a switching element such as a thin film transistor (TFT) in a pixel portion is also described. This is applicable in the configuration of the present invention.

The organic EL lighting device 3 is, as shown in FIG. 2, a third transparent substrate made of glass or the like.

An anode 22 which is a transparent electrode made of ITO or the like is formed on the surface of the auxiliary electrode 23, and an auxiliary electrode 23 is patterned on the anode 22, and an insulating film 2 is formed so as to cover the upper surface of the auxiliary electrode 23. 4, an organic EL layer 25 and a cathode 26 as a metal electrode are sequentially formed on the anode 22 so as to cover the auxiliary electrode 23 and the insulating film 24, and are made of a barrier oxide or the like. A sealing plate 28 is provided above the cathode 26 via a hygroscopic material 27, and the sealing plate 28 is fixed by an adhesive (not shown).

The capture electrodes 23 are arranged in a region other than the display pixel electrode 10, in other words, in a portion matching the non-formation region of the display surface element electrode 10, that is, arranged in a matrix as shown in FIGS. 1A and 1B. The display pixel electrodes 10 are provided in a lattice shape and are made of a metal such as aluminum, silver, chromium, or molybdenum.

The insulating film 24 is made of an insulating inorganic material such as silicon oxide or a photosensitive resin material such as polyimide, and is made of the latter here. The upper surface of the auxiliary electrode 23 is formed in a shape following the auxiliary electrode 23. The insulating film 24 separates the upper surface of the auxiliary electrode 23 from the organic EL layer 25, and the auxiliary electrode 23 and the organic EL layer 25 are located above the auxiliary electrode 23. Insulated with

FIG. 3 is a schematic cross-sectional view showing a configuration of a comparative example (conventional example) of an organic EL lighting device used as a backlight of a liquid crystal display device. In the example of FIG. 3, the organic EL layer 25 is formed directly so as to cover the auxiliary electrode 23 without the insulating film 24 as in the present embodiment.

Since a voltage is applied to the organic EL layer 25 between the anode 22 and the cathode 26 sandwiching the organic EL layer 25, the upper surface of the auxiliary electrode 23 and the organic EL layer 25 are connected in FIG. The continuity between the cathode and the cathode 26 is a major cause of the decrease in the luminous efficiency of the organic EL lighting device 3. Therefore, as in the present embodiment, by forming an insulating film 24 on the upper surface of the auxiliary electrode 23 to insulate the upper surface of the auxiliary electrode 2 from the organic EL layer 25, the luminous efficiency of the organic EL lighting device 3 is improved. Can be improved.

Further, in the case of FIG. 3, there is a possibility that a short circuit or a leak may occur between the trapping electrode 23 and the cathode 26 due to the poor flatness of the metal material. In the present embodiment, by forming the insulating film 24 on the upper surface of the auxiliary electrode 23, the auxiliary electrode 23 and the cathode 26 are separated by the insulating film 24 so that reliable insulation is achieved. Short leak is prevented.

The organic EL layer 25 has a two-layer structure of a hole transport layer / organic light emitting layer from the anode 22 side, and There are three-layer structure of a hole transport layer, an organic light-emitting layer, and an electron transport layer, or a four-layer structure of a hole injection layer, a hole transport layer, an organic light-emitting layer, and an electron transport layer. For example, there is a two-layer organic EL layer using α-NPD as a hole transport layer and Alq as an organic light emitting layer. The device having this configuration emits green light. Further, by adding dopants having various luminescent colors to the organic luminescent layer, organic EL elements having various luminescent colors can be formed.

Further, by adding a dopant emitting light to each of R, G, and B to the organic light emitting layer, or by stacking an organic light emitting layer to which a dopant emitting light to each of R, G, and B is added. An organic EL device that emits white light can be obtained. The cathode 26 is made of an alkali metal such as lithium and an alkali metal compound such as lithium fluoride, which have a small work function, to effectively inject electrons into the organic EL layer 25. However, alkali metals having a small work function of if are unstable, so they are used together with stable metals such as aluminum and silver for stabilization. For example, aluminum monolithium alloy, lithium fluoride / aluminum two-layer birch is used as the cathode 26.

The sealing plate 28 is made of glass or the like, and is used in a dry nitrogen atmosphere using the third transparent substrate 21 and, for example, an epoxy resin adhesive to protect the organic EL layer 25 from the outside air. And sealed.

Then, as shown in FIG. 1C, the liquid crystal cell 2 and the organic EL lighting device 3 face each other, and the polarizing plate 18 of the liquid crystal cell 2 and the third transparent substrate 21 of the organic EL lighting device 3 face each other. As shown in FIGS. 1A and 1B, the grid-like auxiliary electrodes 23 are aligned between the matrix-arranged display pixel electrodes 10 which are regions where the display pixel electrodes 10 are not formed. Thus, the liquid crystal display device 1 is configured.

(Method of manufacturing liquid crystal display device)

4A to 4F are schematic cross-sectional views showing the method for manufacturing the liquid crystal display device according to the above-described present embodiment in the order of steps. Here, the manufacturing process of the organic EL lighting device, which is the main configuration of the liquid crystal display device according to the present embodiment, will be mainly described.

First, as shown in FIG. 4A, an anode 22 made of ITO or the like is formed on a third transparent substrate 21 made of glass or the like, and an electrode material such as aluminum is formed on the anode 22. JP2004 / 006300

(A 1) After forming the film 31, a polyimide film 32 as a photosensitive resin material is applied and formed.

Subsequently, as shown in FIG. 4B, the polyimide film 32 is exposed and developed by photolithography, and the polyimide film 32 is processed to form an insulating film 24 as a pattern. Subsequently, as shown in FIG. 4C, the A1 film 31 is dry-etched using the insulating film 24 as a mask to form a pattern of auxiliary electrodes 2 and 3 following the shape of the insulating film 24. . At this time, the auxiliary electrode 23 is formed so as to be located at a position matching the non-formation region of the display pixel electrode 10 when superimposed on the liquid crystal cell 2.

Subsequently, the surface of the anode 22 is oxidized using oxygen plasma. Thereafter, as shown in FIG. 4D, an organic EL layer 25 is formed on the anode 22 by an evaporation method so as to cover the insulating film 24 and the auxiliary electrode 23. Here, from the anode 22 side, 2TNTATA as a hole injection layer, α—NPD as a hole transport layer, and Alq as a light emitting layer are deposited to form an organic EL layer 25 in a three-layer structure. Then, a cathode 26 is formed on the organic EL layer 25 by depositing LiF to a thickness of 0.5 nm and A1 to a thickness of 200 nm.

Subsequently, as shown in FIG. 4E, using a sealing plate 28 to which a hygroscopic material 27 made of barium oxide or the like is adhered, a third gas is applied with an epoxy resin adhesive under a dry nitrogen atmosphere. The sealing is performed by bonding the glass substrate 21 and the sealing plate 28. Thus, the organic EL lighting device 3 for backlight of the present embodiment is completed. The organic EL lighting device 3 emits green light.

The liquid crystal cell 2 is manufactured by a known method. For example, a plurality of strip-shaped transparent electrodes 11 made of ITO or the like are patterned on the surface of a first transparent substrate 13 made of glass or the like, and then an alignment film 1 is formed so as to cover the transparent electrodes 11. After forming a plurality of strip-shaped transparent electrodes 14 made of ITO or the like and orthogonal to the transparent electrodes 11 on the surface of the second transparent substrate 16 made of glass or the like, the transparent electrodes 1 An alignment film 15 is formed so as to cover 4.

Then, as shown in FIG. 4F, the first and second transparent substrates 13 and 16 are connected to the transparent electrode 11 and the transparent electrode 11 through a spacer for controlling the thickness of the injected liquid crystal. 1 and 4 are orthogonally opposed to each other and bonded together. A crystal layer 17 is formed. Finally, polarizing plates 18 and 19 are formed on the back surfaces of the first and second transparent substrates 13 and 16. As shown by a circle C in the figure, a portion where the strip-shaped transparent electrodes 11 and 13 orthogonal to each other overlap is the display pixel electrode 10.

Thereafter, the liquid crystal cell 2 and the organic EL lighting device 3 are connected to each other, and the polarizing plate 18 of the liquid crystal cell 2 and the third transparent substrate 21 of the organic EL lighting device 3 face each other. The liquid crystal display device 1 is completed by overlapping and fixing the lattice-shaped trapping electrodes 23 between the display pixel electrodes 10 arranged in a matrix, which is a formation region, so as to be aligned. In order to perform this superposition step reliably, it is desirable to provide an alignment mark at an appropriate portion of each of the liquid crystal cell 2 and the organic EL lighting device 3.

As described above, according to the present embodiment, first, since the auxiliary electrode 23 made of a metal material is provided on the anode 22 that is a transparent electrode, the resistance value of the anode 22 can be reduced. A reliable OLED lighting device 3 for backlight, which can prevent light emission unevenness and heat generation due to a voltage drop and achieve clean uniform light emission, is realized. Further, since the auxiliary electrode 23 is provided in a region where the display pixel electrode 10 of the liquid crystal cell 2 is not formed, a decrease in luminance of the organic EL lighting device 3 due to the light shielding of the auxiliary electrode 23 is suppressed. In addition, since the insulating film 24 is formed on the trapping electrode 23, no current flows through the organic EL layer 25 in a portion of the organic EL layer 25 that is shielded from light by the auxiliary electrode 23. Low power consumption of lighting equipment is realized. Further, by forming the insulating film 24, it is possible to prevent short-circuit and leakage between the trapping electrode 23 and the cathode 26 due to poor flatness of the auxiliary electrode 23. As described above, a liquid crystal display device having an organic EL lighting device with high reliability and low power consumption capable of emitting clean uniform light is realized.

Modification 1 of the first embodiment

Here, a modified example of the first embodiment will be described. This modification is different from the first embodiment in that the configuration of the organic EL lighting device of the liquid crystal display device is slightly different. The same components as those of the liquid crystal display device according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

(Configuration of liquid crystal display device)

FIG. 5 is a schematic cross-sectional view illustrating a configuration of an organic EL lighting device that is a component of the liquid crystal display device according to the present modification. The liquid crystal display device of this modification (the liquid crystal display device 41 shown in FIG. 6G) includes a liquid crystal cell 2 similar to the first embodiment, which is a liquid crystal cell, and an organic EL used as a backlight of the liquid crystal cell 2. The lighting device 42 is provided.

In the organic EL lighting device 42, an anode 22 which is a transparent electrode made of IT, etc. is formed on the surface of a third transparent substrate 21 made of glass or the like, and a trapping electrode 23 is formed on the anode 22 in a pattern. An insulating film 43 is formed so as to cover the entire surface of the auxiliary electrode 23, and an organic EL layer 25 and a cathode 26 which is a metal electrode are sequentially formed on the anode 22 so as to cover the insulating film 43. A sealing plate 28 is provided above the cathode 26 via a hygroscopic material 27 made of a barrier oxide or the like, and the sealing plate 28 is fixed by an adhesive (not shown). ing.

The insulating film 43 is made of an insulating inorganic material such as silicon oxide or a photosensitive resin material such as polyimide. In this case, the former is used as the material, and the trapping electrode 23 is shaped like the auxiliary electrode 23. This insulating film 43 separates the trapping electrode 23 from the organic EL layer 25, and insulates the trapping electrode 23 from the organic EL layer 25. ing.

As in the present modification, the insulating film 43 is formed so as to cover the entire surface of the auxiliary electrode 23, and the trapping electrode 23 is insulated from the organic EL layer 25. Luminous efficiency can be improved. Furthermore, by forming the insulating film 43 so as to cover the entire surface of the auxiliary electrode 23, the auxiliary electrode 23 and the cathode 26 are separated by the insulating film 43 to ensure insulation. The above short leak is prevented.

(Method of manufacturing liquid crystal display device)

6A to 6G are schematic cross-sectional views illustrating a method of manufacturing the liquid crystal display device according to the above-described modification in the order of steps. Here, the manufacturing process of the organic EL lighting device, which is the main configuration of the liquid crystal display device according to the present modification, will be mainly described.

First, as shown in FIG. 6A, an anode 22 made of ITO or the like is formed on a third transparent substrate 21 made of glass or the like, and an electrode material such as aluminum (A) is formed on the anode 22. 1) Film 31 is formed.

Subsequently, as shown in FIG. 6B, the auxiliary film 23 is patterned by patterning the A1 film 31 into an electrode shape. At this time, the auxiliary electrode 23 overlaps the liquid crystal cell 2 It is formed so as to be located at a position matching the non-formation region of the display pixel electrode 10 when they are combined.

Subsequently, as shown in FIG. 6C, a silicon oxide film 44 as an insulating inorganic material is formed on the anode 22 so as to cover the auxiliary electrode 23.

Subsequently, as shown in FIG. 6D, the silicon oxide film 44 is patterned in a shape following the auxiliary electrode 23, and an insulating film 43 covering the entire surface of the capture electrode 23 is patterned. .

Subsequently, the surface of the anode 22 is oxidized using oxygen plasma. Thereafter, as shown in FIG. 6E, an organic EL layer 25 is formed on the anode 22 by an evaporation method so as to cover the insulating film 43. Here, from the anode 22 side, 2TNATA as a hole injection layer, a—NPD as a hole transport layer, and Alq as a light emitting layer are deposited to form an organic EL layer 25 in a three-layer structure. Thereafter, a cathode 26 is formed on the organic EL layer 25 by depositing LiF to a thickness of 0.5 nm and Al to a thickness of 200 nm.

Subsequently, as shown in FIG. 6F, using a sealing plate 28 to which a hygroscopic material 27 made of barium oxide or the like is adhered, a third gas is applied with an epoxy resin adhesive under a dry nitrogen atmosphere. The sealing is performed by bonding the glass substrate 21 and the sealing plate 28. In this way, the organic EL lighting device 42 for backlight of the present modified example is completed. The organic EL lighting device 42 emits green light.

Then, as shown in FIG. 6G, the first and second transparent substrates 13 and 16 are connected to the transparent electrode 11 and the transparent electrode 11 through a spacer for controlling the thickness of the injected liquid crystal. 14 are arranged so as to be orthogonal to each other and bonded together, and a liquid crystal is injected into the inside to form a liquid crystal layer 17. Finally, polarizing plates 18 and 19 are formed on the back surfaces of the first and second transparent substrates 13 and 16. As shown by the circle C in the figure, stripes that are orthogonal to each other A portion where the transparent electrodes 11 and 13 overlap each other becomes a display pixel electrode 10.

Thereafter, the liquid crystal cell 2 and the organic EL lighting device 42 are connected to each other, and the polarizing plate 18 of the liquid crystal cell 2 and the third transparent substrate 21 of the organic EL lighting device 3 face each other. A grid-like trapping electrode 23 is overlapped and fixed between the display pixel electrodes 10 arranged in a matrix shape, which is a formation area, so as to be aligned, and the liquid crystal display device 41 is completed. In order to surely perform this superposition step, it is desirable to provide an alignment mark at an appropriate portion of each of the liquid crystal cell 2 and the organic EL lighting device 42.

As described above, according to the present embodiment, first, since the auxiliary electrode 23 made of a metal material is provided on the anode 22 that is a transparent electrode, the resistance value of the anode 22 can be reduced. An organic EL lighting device 42 for a backlight that can prevent light emission unevenness and heat generation due to a voltage drop and achieve clean uniform light emission is realized. In addition, since the auxiliary electrode 23 is provided in a region where the display pixel electrode 10 of the liquid crystal cell 2 is not formed, a decrease in luminance of the organic EL lighting device 42 due to light shielding of the capture electrode 23 is suppressed. In addition, since the insulating film 43 is formed so as to cover the entire surface of the auxiliary electrode 23, no current flows in a portion of the organic EL layer 25 shielded by the auxiliary electrode 23. Thus, low power consumption of the organic EL lighting device is realized. Further, by forming the insulating film 43, it is possible to prevent short-circuit and leakage between the auxiliary electrode 23 and the cathode 26 due to the poor flatness of the auxiliary electrode 23. As described above, a liquid crystal display device having an organic EL lighting device with high reliability and low power consumption capable of emitting clean uniform light is realized.

(Second embodiment)

Hereinafter, a second embodiment of the present invention will be described. The present embodiment differs from the first embodiment in that the configuration of the organic EL lighting device of the liquid crystal display device is slightly different. The same components as those of the liquid crystal display device according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(Configuration of liquid crystal display device)

FIG. 7 is a schematic cross-sectional view illustrating the configuration of an organic EL lighting device that is a component of the liquid crystal display device according to the present embodiment.

The liquid crystal display device of the present embodiment (the liquid crystal display device 51 shown in FIG. 8G) includes a liquid crystal cell 2 similar to that of the first embodiment and an organic EL device used as a backlight of the liquid crystal cell 2. L lighting device 52 is provided.

In the organic EL lighting device 52, a trapping electrode 23 is pattern-formed on the surface of a third transparent substrate 21 made of glass or the like, and ITO is formed on the third transparent substrate 21 so as to cover the auxiliary electrode 23. An anode 22 is formed as a transparent electrode made of the same material.An insulating film 53 is formed on the anode 22 at a position aligned above the trapping electrode 23, and the anode 2 is formed so as to cover the insulating film 53. An organic EL layer 25 and a cathode 26 serving as a metal electrode are sequentially formed on 2, and a sealing plate 28 is provided above the cathode 26 via a hygroscopic material 27 made of, for example, vacuum oxide. The sealing plate 28 is fixed by an adhesive (not shown).

The insulating film 53 is made of silicon oxide, positive photosensitive polyimide, or the like, and is shaped like the auxiliary electrode 23 so as to be aligned with the upper surface of the auxiliary electrode 23 via the anode 22. The insulating film 43 separates the upper surface of the trapping electrode 23 from the organic EL layer 25. The trapping electrode 23 and the organic EL layer 25 are located above the trapping electrode 23. Insulated.

As in the present embodiment, an insulating film 53 is formed at a position aligned above the auxiliary electrode 23 to insulate the trapping electrode 23 from the organic EL layer 25, so that the organic EL lighting device 5 is formed. 2 can improve the luminous efficiency. Further, by forming the insulating film 53 at a position aligned above the trapping electrode 23, the trapping electrode 23 and the cathode 26 are separated by the insulating film 53 to ensure reliable insulation. And the short leak described above is prevented.

(Method of manufacturing liquid crystal display device)

8A to 8G are schematic sectional views showing the method for manufacturing the liquid crystal display device according to the above-described present embodiment in the order of steps. Here, the manufacturing process of the organic EL lighting device, which is the main configuration of the liquid crystal display device according to the present embodiment, will be mainly described.

First, as shown in FIG. 8A, for example, an aluminum (A 1) film 31 is formed as an electrode material on a third transparent substrate 21 made of glass or the like, and then the A 1 film 31 is formed into an electrode shape. The trapping electrode 23 is patterned to form a pattern. At this time, the capture electrode 23 is formed so as to be located at a position matching the non-formation region of the display pixel electrode 10 when it is overlapped with the liquid crystal cell 2.

Subsequently, as shown in FIG. 8B, a positive electrode made of ITO or the like covers the auxiliary electrode 23. Form pole 2 2.

Subsequently, as shown in FIG. 8C, a positive photosensitive polyimide film 54 is applied on the anode 22 to form a film, and then the back surface of the transparent substrate 21 is irradiated with exposure light to form the auxiliary electrode 23. The positive photosensitive polyimide film 54 is exposed and imaged by photolithography using the mask as a mask, and as shown in FIG. 8D, the positive photosensitive polyimide film 54 is processed to form an electrode. An insulating film 53 is formed.

Subsequently, the surface of the anode 22 is oxidized using oxygen plasma. Thereafter, as shown in FIG. 8E, an organic EL layer 25 is formed on the anode 22 by an evaporation method so as to cover the insulating film 53. Here, 2 TNATA as the hole injection layer, α-NPD as the hole transport layer, and Alq as the light emitting layer are deposited from the anode 22 side, and the organic EL layer 25 is formed into a three-layer structure. Form. Thereafter, a cathode 26 is formed on the organic EL layer 25 by depositing LiF to a thickness of 0.5 nm and A1 to a thickness of 200 nm.

Subsequently, as shown in FIG. 8F, using a sealing plate 28 to which a hygroscopic material 27 made of barium oxide or the like is stuck, a third epoxy resin-based adhesive was used in a dry nitrogen atmosphere. The sealing is performed by bonding the glass substrate 21 and the sealing plate 28. Thus, the organic EL lighting device 52 for backlight of the present embodiment is completed. This organic EL lighting device 52 emits green light.

The liquid crystal cell 2 is manufactured by a known method. For example, a plurality of strip-shaped transparent electrodes 11 made of ITO or the like are patterned on the surface of a first transparent substrate 13 made of glass or the like, and then an alignment film 1 is formed so as to cover the transparent electrodes 11. After forming a plurality of strip-shaped transparent electrodes 14 made of ITO or the like and orthogonal to the transparent electrodes 11 on the surface of the second transparent substrate 16 made of glass or the like, the transparent electrodes 1 An alignment film 15 is formed so as to cover 4. '

Then, as shown in FIG. 8G, the first and second transparent substrates 13 and 16 are connected to the transparent electrode 11 and the transparent electrode 11 through a spacer for controlling the thickness of the injected liquid crystal. 14 are arranged so as to be orthogonal to each other and bonded together, and a liquid crystal is injected into the inside to form a liquid crystal layer 17. Finally, polarizing plates 18 and 19 are formed on the back surfaces of the first and second transparent substrates 13 and 16. As shown by a circle C in the figure, a portion where the stripe-shaped transparent electrodes 11 and 13 orthogonal to each other overlap is the display pixel electrode 10. Thereafter, the liquid crystal cell 2 and the organic EL lighting device 52 are opposed to each other, and the polarizing plate 18 of the liquid crystal cell 2 and the third transparent substrate 21 of the organic EL lighting device 3 face each other. A grid-like trapping electrode 23 is overlapped and fixed between the display pixel electrodes 10 arranged in a matrix, which is a formation area, so as to be aligned, and a liquid crystal display device 51 is completed. In order to surely perform this superposition process, it is desirable to provide an alignment mark at an appropriate portion of each of the liquid crystal cell 2 and the organic EL lighting device 52.

As described above, according to the present embodiment, first, the auxiliary electrode 23 made of a metal material is provided in the anode 22 which is a transparent electrode, so that the resistance value of the anode 22 can be reduced. In addition, it is possible to realize a reliable OLED lighting device 52 for a backlight, which can prevent uneven light emission and heat generation due to a voltage drop, and can perform clean uniform light emission. In addition, since the capture electrode 23 is provided in a region where the display pixel electrode 10 of the liquid crystal cell 2 is not formed, a decrease in the brightness of the organic EL lighting device 52 due to the shielding of the capture electrode 23 is suppressed. In addition, since the insulating film 53 is formed above the auxiliary electrode 23, no current flows in the portion of the organic EL layer 25 that is shielded from light by the auxiliary electrode 23. The low power consumption of the lighting device 52 is realized. Further, by forming the insulating film 53, it is also possible to prevent short leakage between the auxiliary electrode 23 and the cathode 26 due to poor flatness of the auxiliary electrode 23. As described above, a liquid crystal display device having an organic EL lighting device with high reliability and low power consumption capable of emitting clean uniform light is realized.

Industrial applicability

ADVANTAGE OF THE INVENTION According to this invention, the luminous efficiency of a backlight is improved, low power consumption is implement | achieved, short circuit and leak of an auxiliary electrode and a 2nd electrode are prevented from occurring, and high reliability and clean uniform light emission are performed. A liquid crystal display device having a possible low power consumption organic EL lighting device is realized.

Claims

The scope of the claims

1. a liquid crystal cell having a liquid crystal layer and comprising a plurality of display pixels;

An organic EL layer for illuminating the liquid crystal layer from behind is sandwiched between a first electrode, which is a transparent electrode, and a second electrode, which is a metal electrode. Lighting means arranged to face each other;

An auxiliary electrode provided at a position matching the non-formation region of the display pixel and electrically connected to the first electrode;

A liquid crystal display, comprising: an insulating film provided on a surface of the organic EL layer at a position matching the region where the auxiliary electrode is formed, and at least partially insulating the organic EL layer and the auxiliary electrode. apparatus.

2. The liquid crystal display device according to claim 1, wherein the insulating film is formed on the first electrode so as to cover at least an upper surface of the trapping electrode.

3. The liquid crystal display device according to claim 1, wherein the insulating film is formed on the first electrode so as to cover the entire surface of the capture electrode.

4. The insulating film according to claim 1, wherein the insulating film is formed at a position matching the trapping electrode embedded in the first electrode with the first electrode interposed therebetween. The liquid crystal display device according to the above.

5. The liquid crystal display device according to claim 1, wherein the insulating film is made of an insulating resin.

6. a step of sequentially forming a first electrode which is a transparent electrode, an electrode material, and an insulating resin on the surface of the transparent substrate;

Processing the insulating resin by lithography to form an electrode-shaped insulating film;

Processing the electrode material using the insulating film as a mask to form a pattern of an auxiliary electrode;

Sequentially forming an organic EL layer and a second electrode that is a metal electrode on the first electrode so as to cover the auxiliary electrode with the insulating film interposed therebetween;

A liquid crystal cell having a liquid crystal layer and a plurality of display pixels formed thereon and the back of the transparent substrate And disposing the surface facing each other such that the trapping electrode is located at a position matching the non-forming region of the display pixel.

A method for manufacturing a liquid crystal display device, comprising:

7. a step of sequentially forming a first electrode, which is a transparent electrode, and an electrode material on the surface of the transparent substrate;

Processing the electrode material and forming a pattern of the capture electrode,

Forming an insulating material on the first electrode so as to cover the trapping electrode; applying the insulating material to form an insulating film covering the trapping electrode according to the shape of the auxiliary electrode; The process of

A liquid crystal cell having a liquid crystal layer and having a plurality of display pixels formed thereon and a back surface of the transparent substrate are disposed so as to face each other such that the auxiliary electrode is located at a position where the auxiliary electrode is aligned with a region where the display pixels are not formed. Process and

A method for manufacturing a liquid crystal display device, comprising:

8. a step of patterning an auxiliary electrode on the surface of the transparent substrate;

Forming a first electrode that is a transparent electrode and an insulating resin on the transparent substrate sequentially so as to cover the auxiliary electrode;

The insulating resin is processed into a shape following the auxiliary electrode using the auxiliary electrode as a mask by lithography irradiating from the back surface of the transparent substrate, and a region for forming the auxiliary electrode on the first electrode is formed. Forming an insulating film in a portion matching the

Sequentially forming an organic EL layer and a second electrode which is a metal electrode on the first electrode so as to cover the insulating film;

A liquid crystal cell having a plurality of display pixels having a liquid crystal layer and a back surface of the transparent substrate are disposed so as to face each other such that the trapping electrode is located at a position matching the non-formation region of the display pixels. Process and

A method for manufacturing a liquid crystal display device, comprising: