JP2009283246A - Optical member used for electroluminescent element, and electroluminescent element equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroluminescent element for suppressing brightness rise of black display by outdoor daylight which is a shortcoming of an EL display combining a circular polarizing plate method and a circular polarizing separation layer, and of improving light utilization efficiency. <P>SOLUTION: The electroluminescent element has an electroluminescent layer in which a plurality of light-emitting regions are arranged in an array of pixels, the circular polarizing plate installed on a visible side of the electroluminescent layer, and a light reflecting layer installed on the opposite side of the visible side of the electroluminescent layer. A circular polarizing separation layer and a light shielding layer are installed between the circular polarizing plate and the electroluminescent layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical member for use in an electroluminescent element, which is provided between a circularly polarizing plate and an electroluminescent layer, and includes a light shielding layer and a polarization separation layer.

  In recent years, as a next-generation display, an EL display element including an electroluminescence (hereinafter sometimes abbreviated as EL) element is expected. There are two types of EL elements: inorganic EL elements and organic EL elements. Each EL element is self-luminous and has high visibility, and since it is a completely solid element, it has excellent impact resistance and is easy to handle. There is an advantage of being. For this reason, research and development and practical application as a pixel of a graphic display, a pixel of a television image display device, a surface light source, and the like are in progress.

  The organic EL element includes an EL layer made of a fluorescent organic solid such as anthracene and a hole injection layer made of a triphenylamine derivative, or an electron injection layer made of an EL layer and a perylene derivative, or a hole injection layer. In other words, the stacked structure of any one of the EL layer and the electron injection layer is interposed between a pair of electrodes (the light emitting surface side electrode is a transparent electrode). Such an organic EL element utilizes light emission generated when electrons and holes injected into the EL layer recombine. For this reason, the organic EL element can be driven at a low voltage of, for example, 4.5 V by reducing the thickness of the EL layer, and has a high response because the luminance is proportional to the injected current. An advantage is that a luminance EL element can be obtained. In addition, by changing the type of the fluorescent organic solid used as the EL layer, light emission is obtained in all the visible colors of blue, green, yellow, and red. Since the organic EL element has such advantages, in particular, that it can be driven at a low voltage, research for practical application is currently underway. Some small displays, such as display portions of mobile phones, which are relatively difficult to manufacture, have been put into practical use.

  As a color display method in the organic EL element, (1) a three-color coating method for forming a light emitting material of each color such as blue, red, and green, (2) an EL layer emitting blue light, and from blue to green, And a CCM system for generating three colors by combining color conversion layers (CCM layers) for color conversion from blue to red, respectively, and (3) an EL layer that emits white light, and color filters such as blue, red, and green Combination methods, etc. are mentioned. Among these, from the viewpoint of luminous efficiency, the three-color painting method (1) is the most powerful and has been put to practical use in mobile phones, portable information terminals (also referred to as PDAs) and the like.

  In these organic EL elements, since the electrode is made of a metal material, there is a problem that display contrast is remarkably lowered due to reflection of external light when it is assumed to be used in a bright environment. As measures for improving such problems, (1) a circularly polarizing plate is attached to the manside side of the organic EL element, (2) a color filter is applied, and (3) an achromatic color or an achromatic color is used. Various measures such as (so-called tint processing) are taken. Here, when the circularly polarizing plate (1) is applied, in principle, reflection of external light is completely suppressed (depending on the incident angle of external light), but light emission from the organic EL element is more than half of that. Was absorbed by the circularly polarizing plate and was not necessarily efficient. On the other hand, when the color filter of (2) is applied, high light utilization efficiency is obtained and the color tone is improved, but the effect of suppressing external light reflection is inferior compared with the case of using a circularly polarizing plate.

  At present, extending the life of organic EL elements is a major issue. In the organic EL element, it is possible to increase the luminance by causing a current to flow through a light emitting body that is an organic substance to emit light and further increasing the current value. For this reason, when there is a situation where the current value must be increased, such as when light emission is performed at a high luminance or when it is necessary to keep the luminance constant, deterioration of the light emitter itself can be avoided. Therefore, the lifetime of the element is shortened. Therefore, after the light is emitted from the light emitter, suppressing the light absorption by the peripheral members as low as possible suppresses the current value, leading to a long life.

Since the circularly polarizing plate method can realize high contrast even in a bright place, it is a useful method as an EL display. However, there is a problem in light use efficiency for the above reasons, and in order to solve this problem, Japanese Patent Laid-Open No. 2001-357799 (Patent Document 1) proposes an EL display device including a circularly polarized light separating layer. . In this EL display device, a circularly polarized light separating layer is disposed between the circularly polarizing plate and the EL element in order to prevent the emitted EL light from being absorbed by the circularly polarizing plate. The EL light that should be absorbed is reflected to the EL element side by the circularly polarized light separating layer, and is reflected again by the reflective layer (reflective electrode) on the back surface of the EL element, thereby reversing the circularly polarized state of the reflected light. The reflected light can pass through without being absorbed by the circularly polarized light separating layer and the circularly polarizing plate. Therefore, it is possible to theoretically increase the light utilization efficiency by about twice.
JP 2001-357799 A

  However, the EL display device disclosed in Japanese Patent Laid-Open No. 2001-357979 can improve the light utilization efficiency, but at the same time, it cannot obtain the merit of the circularly polarizing plate system that can absorb external light. In other words, since the mechanism for improving the light utilization efficiency by the circularly polarized light separating layer is also applied to external light, the external light that should be completely absorbed by the circularly polarizing plate is originally converted into the polarizing plate by the circularly polarized light separating layer. Therefore, there is a problem that the contrast in a bright place is remarkably lowered.

  Accordingly, an object of the present invention is to suppress the increase in luminance of black display due to external light, which has been a defect of an EL display device combining a circularly polarizing plate system and a circularly polarized light separating layer, and to improve light utilization efficiency. An object of the present invention is to provide an optical member used for an electroluminescent element.

An optical member according to the present invention includes an electroluminescent layer in which a plurality of light emitting regions are arranged in a pixel shape, a circularly polarizing plate provided on the viewing side of the electroluminescent layer, and the electroluminescent layer. A light reflecting layer provided on the opposite side of the viewing side, and an optical member used for an electroluminescent device comprising:
Comprising a circularly polarized light separating layer and a light shielding layer,
The circularly polarized light separating layer and the light blocking layer are arranged between the circularly polarizing plate and the electroluminescent layer.

  As another aspect of the present invention, there is also provided a color filter including the optical member and a colored layer that transmits the wavelength of light from the light emitting region of the electroluminescent layer.

  Furthermore, as another aspect of the present invention, an electroluminescent layer in which a plurality of light emitting regions are arranged in a pixel shape, a circularly polarizing plate provided on the viewing side of the electroluminescent layer, and the electroluminescent layer are provided. There is also provided an electroluminescent device including a light reflecting layer provided on the opposite side of the cent layer to the viewing side and the optical member.

  According to the present invention, it is possible to suppress an increase in black display luminance due to external light, which is a defect of an EL display device that combines a circularly polarizing plate system and a circularly polarized light separating layer. Furthermore, since the effect of improving the light utilization efficiency can be maintained, a high contrast can be obtained even in a bright place.

  Further, in the present invention, since the light use efficiency can be improved, when the EL display device is used with the conventional luminance, the light emission intensity of the EL element itself can be reduced, so that the life of the device can be extended. .

  Hereinafter, although the embodiment of the optical member of the present invention is described, the present invention is not limited to the following embodiment.

<Basic configuration and operation>
First, the basic configuration and operation of the present invention will be described. FIG. 1 shows a basic layer structure of an EL element provided with an optical member according to the present invention.

  The EL element provided with the optical member of the present invention includes an EL layer 1, a reflective layer 3 provided on the back surface (opposite side) of the EL layer 1, and a circularly polarizing plate provided on the visual side of the EL layer 1. 2, and a light shielding layer 5 and a circularly polarized light separating layer 4 are provided between the circularly polarizing plate 2 and the EL layer 1. Here, the circularly polarized light separating layer 4 is disposed so as to overlap at least the light emitting region of the organic EL layer 1, while the light shielding layer 5 is disposed so as to cover a portion other than the light emitting region.

  Here, when the circularly polarizing plate 2 has a characteristic of transmitting only the left circularly polarized light in the incident light from the viewing side (conversely, converting the left circularly polarized light from the back side to linearly polarized light), Similarly, the circularly polarized light separating layer 4 transmits only the left circularly polarized light. If the circularly polarizing plate 2 transmits only the right circularly polarized light, the circularly polarized light separating layer 4 also transmits only the right circularly polarized light. The characteristic of the circularly polarized light separating layer 4 is that it reflects circularly polarized light that does not pass through without changing its polarization state. For example, a circularly polarized light separating layer that transmits left circularly polarized light reflects right circularly polarized light as right circularly polarized light. Other members have no polarization characteristics. For example, the light shielding layer 5 blocks visible light regardless of the polarization state. As an example, the aperture ratio of the light shielding layer 5, that is, the ratio of the area that blocks light and the area that transmits light is 50%.

  The behavior of image light (EL light) will be described. Here, the case where the polarized light transmitted by the circularly polarizing plate 2 is left circularly polarized light will be described.

  The light emitted from the EL layer 1 is substantially non-polarized light (that is, the state of right circularly polarized light: left circularly polarized light = 50%: 50%). Since the EL layer 1 emits light from both the front and back surfaces, the light emitted to the reflective layer side is reflected to the viewing side by the reflective layer. The sum of the reflected light and the light emitted toward the viewing side is set to a state where the EL element emits 100%. When the light emitted to the viewing side passes through the circularly polarized light separating layer 4, the left circularly polarized light component passes as it is and reaches the circularly polarizing plate 2. Since the circularly polarizing plate transmits the left circularly polarized component, the left circularly polarized component of the EL light is transmitted to the viewer side without being absorbed by each member, and the light is transmitted to the observer as an image. In this case, ideally, 50% of the light emitted from the EL layer toward the viewer side can be extracted. On the other hand, the right circularly polarized light component reflected by the circularly polarized light separating layer is reflected to the viewing side in the reflective layer 3 on the back side of the EL layer 1 (at this time, the reflectance is ideally 100%). Since the circularly polarized state is inverted during this reflection, the reflected EL light becomes left circularly polarized light. The left circularly polarized light obtained by converting the reflected light of the right circularly polarized light acts in the same manner as the left circularly polarized light, so that ideally 50% of light can be extracted. Therefore, both left-handed polarized light and right-handed circularly polarized light separated by the circularly polarized light separating layer can be extracted. Therefore, ideally, 100% EL light can be used as image light, and the light utilization efficiency is 100. %.

  In contrast, the conventional circularly polarizing plate type EL display device as shown in FIG. 17 does not include the circularly polarized light separating layer, so that the right circularly polarized light emitted from the EL layer 1 also reaches the circularly polarizing plate 2. And will be absorbed. As a result, only the left circularly polarized light can be extracted as image light, and the light use efficiency is 50% in principle. On the other hand, a conventional circularly polarizing plate type EL display element having a circularly polarized light separating layer as shown in FIG. 18 has light use efficiency equivalent to that of the present invention with respect to image light.

  Next, the behavior of external light (incident light from the viewing side) when the optical member according to the present invention is applied to an EL element will be described. Since external light is non-polarized light (right circularly polarized light: left circularly polarized light = 50%: 50%), right circularly polarized light is absorbed and only left circularly polarized light is transmitted when passing through the circularly polarizing plate. Further, when the aperture ratio is 50% when passing through the light shielding layer, the left circularly polarized light is 25% of the entire outside light. This left circularly polarized light is incident on the EL layer 1 and behaves the same as the right circularly polarized light described for the image light, so that the left circularly polarized light is transmitted to the viewing side. Therefore, 25% of the outside light is emitted to the viewing side.

  On the other hand, a conventional circularly polarizing plate type EL display (FIG. 18) having a circularly polarized light separating layer is not provided with a light shielding layer, so that external light is not dimmed. 50% of light will be transmitted to the viewer side. On the other hand, in the conventional circularly polarizing plate type EL display (FIG. 17), the left circularly polarized light out of the external light is converted into the right circularly polarized light by the reflective layer 3 and then absorbed by the circularly polarizing plate 2. , The outside light becomes 0%.

  As described above, according to the present invention, the light use efficiency of the image light is improved, and the amount of light emitted from the outside light to the viewing side can be halved. Therefore, the contrast in a bright place is improved and the light use efficiency is high. Can be realized.

<Laminated structure of EL element>
The order of stacking the light shielding layer and the circularly polarized light separating layer is not particularly limited, but the following advantages are obtained depending on the stacking order.

  As shown in FIG. 2, when the circularly polarized light separating layer 4 and the light shielding layer 5 are laminated in this order from the viewing side, the circularly polarized light separating layer 4 can be arranged directly on the base material 7, so that flatness is obtained and polarization selection is achieved. Control of the reflection direction of reflection can be improved and stray light can be reduced. As a result, light utilization efficiency is improved.

  On the other hand, as shown in FIG. 3, when the light shielding layer 5 and the circularly polarized light separating layer 4 are laminated in order from the viewing side, the light shielding layer 5 is disposed at a position close to the viewing side with respect to external light. Since the interface reflection can be eliminated and the light shielding property can be improved, the effect of suppressing external light can be improved.

  Further, as shown in FIG. 4, the circularly polarized light separating layer 4 is patterned and the circularly polarized light separating layer overlapping the light shielding layer 5 is removed, so that the light shielding layer 5 is exposed on the EL layer 1 side. Of the light components that are repeatedly reflected between the polarization separation layer 4 and the reflection layer 3, light that travels in an oblique direction as stray light is absorbed by the light shielding layer, and as a result, the black display becomes blacker and the contrast is improved.

<Action of colored layer>
In the present invention, a colored layer 12 may be provided in addition to the light shielding layer, as shown in FIGS. The operation when the colored layer is provided will be described first in the case where the EL element emits a different color for each pixel.

  The colored layer 12 is disposed in accordance with the light emission of the EL layer for each pixel. For example, if the EL emission is blue, a colored layer having high transmittance in the blue wavelength region is provided. Thereby, the loss of the amount of EL light can be minimized. The action of the colored layer is primarily to suppress external light. By absorbing external light incident on the opening as much as possible, the brightness of black display can be further reduced, that is, the contrast can be improved. Specifically, in the case of a pixel displaying blue, a colored layer that has high blue transmittance and absorbs visible light such as green and red is disposed. Since the EL layer emits blue light, the transmittance is high and there is almost no influence on the image light. However, with respect to external light, since light other than blue is absorbed, only external light can be suppressed. Second, the color reproducibility of the display can be improved. The EL emission spectrum does not have a perfect RGB balance, and the color reproduction range may be narrow if the emission color is used as it is. Here, by using the colored layer and correcting the color of the image light, high color reproducibility can be realized.

  Next, the case where the EL layer emits white light will be described. When the EL light is white, it is impossible to express a color, so a monochrome display is obtained unless a colored layer is provided. By providing the colored layer, color display is possible. As other effects, as described above, an effect of suppressing external light and an effect of improving color reproducibility are exhibited. Although there is no restriction | limiting in particular in the lamination | stacking order of a colored layer, It has the following effect according to the positional relationship with a circularly polarized light separation layer, respectively.

  As shown in FIG. 7, when the colored layer 12 and the circularly polarized light separating layer 4 are laminated in order from the viewing side, the phenomenon in which external light is reflected by the circularly polarized light separating layer 4 and the color of the black display changes depending on the viewing angle is suppressed. can do. The reflection wavelength of the circularly polarized light separating layer 4 may change depending on the incident angle. When a part of the external light incident from the viewing side is reflected by the circularly polarized light separating layer 4, the light is visible to the observer. Depending on the incident angle of external light or the angle viewed by the observer, the wavelength range reflected by the circularly polarized light separating layer 4 changes, and the color of black display changes. The color change of black refers to a state in which, for example, reddish black changes to bluish black. As shown in FIG. 7, if the colored layer 12 is arranged on the viewing side, incident light outside the specific wavelength region is absorbed by the colored layer 12 before being reflected by the circularly polarized light separating layer 4. The light reflected by the circularly polarized light separating layer 4 is limited, and as a result, changes in the intensity of the reflected color and the color of the reflected color can be reduced. Further, since the light reflected by the circularly polarized light separating layer 4 passes through the colored layer again, the effect is simply doubled.

  As shown in FIGS. 5 and 6, when the circularly polarized light separating layer 4 and the colored layer 12 are stacked in this order from the viewing side, the colored layer 12 is disposed between the circularly polarized light separating layer 4 and the reflective layer 3. Therefore, there are the following two effects. One is that EL light is repeatedly reflected between the circularly polarized light separating layer 4 and the reflective layer 3 so that the EL light passes through the colored layer 12 by the repetitive amount. Color reproducibility is improved. Another advantage is that black light can be improved by efficiently absorbing unnecessary light such as external light and video light (light traveling in an oblique direction has a wavelength that is unnecessary for the pixel).

<Operation of circularly polarized light separating layer>
The circularly polarized light separating layer constituting the optical member according to the present invention transmits only the left circularly polarized light component (or right circularly polarized light component) of the linearly polarized light and reflects the right circularly polarized light component (or left circularly polarized light component). It has the function to do. The reflection wavelength region of the circularly polarized light separation layer is not particularly limited, but the following effects can be obtained by selectively reflecting only a specific wavelength region.

  As shown in FIG. 10, when the circularly polarized light separating layer is a narrow-band reflective layer having a reflection peak wavelength corresponding to each emission wavelength region of the EL layer, the light use efficiency is improved only for the wavelength of the EL light. For this reason, the effect is relatively small with respect to external light having a wavelength over the entire visible light range, and a reduction in contrast due to external light can be further suppressed. In addition, color purity can be improved by appropriately combining each emission spectrum from the EL layer and the reflection wavelength region of the circularly polarized light separating layer. The selection of the selective reflection wavelength region can be appropriately determined based on the transmission spectrum of the colored layer as shown in FIG.

  As shown in FIG. 11, when the circularly polarized light separating layer is a broadband reflection layer having a reflection band corresponding to the entire emission wavelength region of the EL layer, the visible light region covering the wavelength region where the EL light is emitted. In order to increase the light utilization efficiency, the luminance is improved and a bright image can be obtained. In addition, when the circularly polarized light separating layer has an incident angle dependency of the reflection area, the broadband reflection can avoid the color shift of the image light. Furthermore, since it is not necessary to change the configuration of the circularly polarized light separating layer for each pixel, it can be manufactured by the same material and the same process, so that the manufacturing merit is great. The selection of the selective reflection wavelength region can be appropriately determined based on the transmission spectrum of the colored layer as shown in FIG.

  In the present invention, when the emission wavelength region of the EL layer is blue (blue pixel), the circularly polarized light separating layer has a narrow band reflection layer having a reflection peak wavelength shorter than the blue emission peak wavelength from the EL layer. (FIG. 10). By using such a circularly polarized light separating layer, the intensity of light having a deeper blue wavelength in the emission spectrum of the EL element is increased due to the effect of improving the light utilization efficiency of the circularly polarized light separating layer. Can be a deep blue having a color purity higher than the original blue of the EL element. As a result, the color reproduction range of the video is expanded, and a clearer and more colorful EL element can be realized. In addition, when the transmission wavelength region of the colored layer is blue, the circularly polarized light separating layer is a narrow band reflection layer having a reflection peak wavelength shorter than the blue transmission peak wavelength of the colored layer. The blue color visually recognized by the observer can be a deep blue color having a higher color purity than the blue color of the colored layer (FIG. 12).

  Similarly, in the case where the emission wavelength range of the EL layer is red (red pixel), the circularly polarized light separating layer is a narrow band reflection layer having a reflection peak wavelength longer than the red emission peak wavelength from the EL layer. (FIG. 10). By using such a circularly polarized light separating layer, the intensity of light having a deeper red wavelength in the emission spectrum of the EL element is increased due to the effect of improving the light utilization efficiency of the circularly polarized light separating layer. Can be a deep red color having a higher color purity than the original red color of the EL element. As a result, the color reproduction range of the video is expanded, and a clearer and more colorful EL element can be realized. In addition, when the transmission wavelength region of the colored layer is red, the circularly polarized light separating layer is a narrow band reflection layer having a reflection peak wavelength longer than the red transmission peak wavelength of the colored layer, thereby obtaining image light. The red color visually recognized by the observer can be a deep red color having a higher color purity than the red color of the colored layer (FIG. 12).

  In the present invention, the reflection wavelength band of the circularly polarized light separating layer can be narrower than the transmission wavelength band of the colored layer or the emission wavelength band of EL light in each pixel. By using such a circularly polarized light separation layer, light having a narrower wavelength range than the original EL emission can be extracted as image light, so that the color reproducibility of the image is expanded and a vivid image can be obtained.

  The reflection directivity of the circularly polarized light separation layer is not particularly limited regardless of whether it is specular reflection or diffuse reflection, but has the following effects.

  As shown in FIG. 14, when the selective reflection of circularly polarized light is specular reflection, the directivity of light existing between the circularly polarized light separating layer and the reflective layer is maintained, so that stray light such as light traveling obliquely Generation | occurrence | production can be suppressed and the brightness | luminance of black display can be made small.

  On the other hand, as shown in FIG. 15, when the selective reflection of circularly polarized light is diffuse reflection, the incident angle dependency of the selectively reflected light can be reduced, and the color shift of black display due to external light can be reduced. . Further, in the case of diffuse reflection, it is preferable to have sandwich diffuse reflection as shown in FIG.

  Although the operation of the EL element to which the optical member according to the present invention is applied has been described above, the optical member of the present invention is applied to an EL element having pixels of each color of red (R), green (G), and blue (B). Needless to say, the present invention can be applied to each pixel, and can also be applied to an EL element including colors other than RGB, that is, having four or more pixels.

  Hereinafter, each member constituting the EL element will be described.

<Base material (viewing side)>
Since the substrate 7 on the viewing side is disposed on the light emitting side, a transparent substrate having good light transmittance is used. For example, a transparent substrate made of a material having good light transmissivity, such as glass, quartz, or various resins, is used. The size and thickness of the substrate are not particularly limited. However, in the present invention, since the circularly polarized light is controlled in the laminate, it is desirable to use a substrate having no birefringence. In particular, a stretched film made of a resin requires attention, and it is preferable to use an unstretched film formed without stretching. In general, a TAC film that is generally used in a liquid crystal display can be used.

<Circularly polarizing plate>
The circularly polarizing plate 2 has a basic configuration in which a quarter-wave retardation plate is bonded to a linearly polarizing plate. Usually, an iodine-type material absorbing polarizing plate is used for the linearly polarizing plate. The quarter-wave retardation plate is generally a stretched film, and has a function of transmitting light incident from the linearly polarizing plate side as circularly polarized light. In general, a broadband retardation plate that works to shift the phase of a quarter wavelength over the entire visible light region is used. The circularly polarizing plate is not particularly limited, and a commercially available one can be used, for example, a circularly polarizing plate manufactured by 3M.

<Light shielding layer>
The light shielding layer 5 includes an opening (an area through which light is transmitted) and a light shielding part (an area through which light is blocked) formed in a predetermined pattern, and is sometimes referred to as a black matrix. The opening is a pixel area. In an EL element, the opening serves as a window through which emitted EL light passes to the viewing side. On the other hand, the light shielding portion is an area that completely shields at least visible light, and has a role of covering other than the EL light emitting region.

  The pattern of the light shielding layer corresponds to the pattern of the EL layer, and is usually a matrix shape or a stripe shape. The shape of the opening can be various shapes such as a square, a circle, and a honeycomb.

  The aperture ratio (area ratio of the aperture), which is the ratio between the light shielding portion and the aperture, is preferably 40% or less, and more preferably 20% or less. In this way, by reducing the ratio of the openings, the influence of external light is suppressed and image light with high contrast can be obtained.

  The light shielding layer is usually configured using a photoresist, a printing ink containing a black pigment, a binder resin, and a solvent, or a metal such as chromium. Examples of the black pigment include carbon black and titanium black, and examples of the binder resin include a copolymer of benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate. As a solvent, the same thing as the coating liquid for coloring layer formation mentioned later can be used. The light shielding layer 5 can be formed by photolithography, various pattern printing methods, various plating methods, and the like.

<Colored layer>
In the present invention, a colored layer can be provided as shown in FIGS. The colored layer is provided in a predetermined pattern mainly in the opening of the light shielding layer, and may be called a color filter. As the colored layer, in addition to the generally provided red colored layer (R), green colored layer (G), and blue colored layer (B), a cyan colored layer and a magenta colored layer may be further provided.

  The light transmission peak of the colored layer is preferably close to 100%. In order to increase the light utilization efficiency, it is desirable that the transmittance with respect to the wavelength of the EL light is high, preferably 80% or more, and more preferably 90% or more. Further, it is desirable that the transmittance is close to 0% in a wavelength region other than the wavelength region of EL light. This is because extra light such as outside light can be absorbed and the contrast can be improved, and is preferably 50% or less, more preferably 30% or less. The transmittance can be determined by appropriately adjusting the concentrations of pigment species and dye species described later.

  In the present invention, when the circularly polarized light separating layer 4 is provided in the opening of the light shielding layer 5 and the colored layer 12 is laminated on the circularly polarized light separating layer 4 (FIG. 6), and the opening of the light shielding layer 5 is colored. In any case where the layer 12 is provided and the circularly polarized light separating layer 4 is provided on the colored layer 12 (FIG. 7), the aperture ratio of the light shielding layer is 40% or less and the transmittance of the colored layer Is preferably 80 to 100%. By setting the aperture ratio of the light-shielding layer and the transmittance of the colored layer in the above ranges, an EL element with better contrast of video light can be obtained. More preferably, the aperture ratio is 20% or less, and the transmittance of the colored layer is 60 to 100%.

  The colored layer includes a pigment dispersion type composed of pigment pigments and a dye-containing type composed of dye pigments. In general, pigment systems are widespread, and examples of blue pigments include blue copper phthalocyanine pigments, and mixtures of blue copper phthalocyanine pigments and purple dioxazine pigments. The pigment pigment | dye which comprises a red colored layer is not specifically limited, A various thing can be used. Examples include anthraquinone pigments and diketopyrrolopyrrole pigments. In addition, an isoindolinone pigment or a nickel azo complex pigment can be mixed as a yellow pigment for color tone adjustment. The pigment coloring matter constituting the green colored layer is not particularly limited, and various types can be used. Examples thereof include phthalocyanine pigments. Similarly, in the green coloring layer, an isoindolinone pigment or a nickel azo complex pigment can be mixed as a yellow pigment for adjusting the color tone. These colored layers can be formed from a composition containing a pigment or dye, a binder resin, a dispersant, a solvent, a surfactant, a photopolymerization initiator, and the like, and conventionally known ones can be blended.

  Examples of the binder resin include a copolymer of benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate.

  Solvents include hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene and tetralin, ethers such as methoxybenzene, 1,2-dimethoxybenzene and diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. , Ketones such as 2,4-pentanedione, ethyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, esters such as g-butyrolactone, 2-pyrrolidone, N-methyl- Amide solvents such as 2-pyrrolidone, dimethylformamide, dimethylacetamide, chloroform, dichloromethane, carbon tetrachloride, dichloroethane Halogen solvents such as tetrachloroethane, tritrichloroethylene, tetrachloroethylene, chlorobenzene, orthodichlorobenzene, t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethyl cell One kind or two or more kinds of alcohols such as sorb and butylcellsolve, phenols such as phenol and parachlorophenol can be used. If only one kind of solvent is used, there is a risk that the solubility of the resist composition is insufficient, or the material (material constituting the base material) that is the other side of coating when the resist is applied may be affected. In some cases, these disadvantages can be avoided by using a mixture of two or more solvents.

  Moreover, as surfactant mix | blended as needed, a fluorosurfactant, a nonionic surfactant, etc. can be mentioned.

  The colored layer having a predetermined pattern is formed using a photoresist or printing ink containing a coloring matter, a binder resin, and a solvent corresponding to each colored layer as the colored layer material. As a formation method of the colored layer 3, it can form by various pattern printing methods, such as photolithography and an inkjet method.

<Electroluminescent layer>
As shown in FIG. 8, the EL layer 1 is a three-color organic EL layer in which at least a red EL layer (R), a green EL layer (G), and a blue EL layer (B) are partitioned by partition walls. Alternatively, as shown in FIG. 9, the organic EL layer emits white light and is not separately applied to each pixel. Each layer of the organic EL layer is laminated on a substrate in the order of a reflective electrode, an EL layer, a transparent electrode, and a protective film.

  The type, size, thickness, etc. of the substrate on the EL side are not particularly limited, and can be appropriately determined depending on the use of the organic EL layer, the material of each layer laminated on the substrate, and the like. For example, a material such as a metal such as Al, glass, quartz, or various resins can be used. In addition, since the light emitted from the EL layer is emitted to the viewing side, it is not always necessary to use a material that becomes transparent or translucent, and an opaque material may be used for the base material.

  The reflective electrode is either an anode or a cathode, but is generally provided on a substrate as an anode, and a hole injection layer and a hole transport layer are provided on the electrode. Examples of the forming material include metals such as gold, silver, and chromium. Moreover, it can also be set as the reflection type electrode which consists of a laminated structure of ITO, silver, and ITO. The reflective electrode has a reflectance of 30% or more, preferably 50%. When light is repeatedly reflected between the circularly polarized light separating layer and the reflective electrode, the light utilization efficiency can be further improved by setting the reflectance to 30% or more.

  As the EL layer, a red EL layer (R), a green EL layer (G), and a blue EL layer (B) are provided at predetermined positions, respectively, and conventionally known materials are used as materials for forming the EL layers of the respective colors. Can be used. Specifically, when the electrode is an anode, the EL layer is a laminate composed of a hole injection layer and an EL layer, or a laminate composed of a hole injection layer, an EL layer, and an electron injection layer from the electrode side. Or a laminate composed of an EL layer and an electron injection layer. A hole transport layer may be provided between the hole injection layer and the EL layer, or an electron transport layer may be provided between the EL layer and the electron injection layer. Each injection layer or EL layer may contain a hole transporting material or an electron transporting material.

  As a material for forming the hole injection layer, for example, a material usually used as a material for a hole injection layer such as a dye material, a metal complex material, or a polymer material can be used. Moreover, as a forming material of a positive hole transport layer, what is normally used as a material for positive hole transport layers, such as phthalocyanine and naphthalocyanine, can be used.

Each color EL layer is a layer formed of an EL layer forming material containing a host material and a guest material, and the host material and guest material can be those conventionally known, and their combination The ratio is arbitrarily selected depending on the material used. As an example of the EL layer forming material of each color, for the red EL layer, 4,4-N, N′-dicarbazole-biphenyl (CBP) is used as the host material and tris (1-phenylisoquinoline is used as the guest material. ) Iridium (III) complex (Ir (piq) ₃ ) can be used, and for the green EL layer, 4,4-N, N′-dicarbazole-biphenyl (CBP) is used as a host material and a guest material And tris (2-phenylpyridine) iridium (III) complex (Ir (ppy) ₃ ). For blue EL layers, 9,10-di-2-naphthylanthracene (DNA) is used as a host material. As a guest material, 1-tert-butyl-perylene (TBP) can be used.

  Note that EL layer forming materials other than those described above may be used. Examples of the host material include anthracene derivatives, arylamine derivatives, distyrylarylene derivatives, carbazole derivatives, fluorene derivatives, spiro compounds, and the like. Examples of guest materials include perylene derivatives, pyrene derivatives, distyrylarylene derivatives, arylamine derivatives, fluorene derivatives, iridium complexes such as FIrPic, and the like.

  Examples of the material for forming the electron transport layer include materials generally used as the electron transport layer, such as metal complex materials, oxadiazole derivatives, triazole derivatives, and phenanthroline derivatives. Examples of the material for forming the electron injection layer include materials generally used for the electron injection layer, such as aluminum and lithium fluoride, in addition to the materials exemplified as the light emitting material for the EL layer.

  In the present invention, when an EL layer is combined with a colored layer, light emission of the EL layer does not need to be color-coded for each pixel such as RGB, and an EL material that emits white light can be used as appropriate.

The transparent electrode 11 forms a counter electrode of the reflective electrode and is either a cathode or an anode, but is generally provided as a cathode. Since the transparent electrode is on the light extraction side, the forming material is a transparent conductive material such as ITO (indium tin oxide), indium oxide, IZO (indium zinc oxide), SnO ₂ , ZnO, or a translucent metal made of MgAg or the like. Is preferably used.

  The partition wall 9 can be formed of an inorganic material such as silicon oxide or an organic material such as a resist, and is formed in a predetermined pattern after the electrodes are patterned and before the EL layer 1 of each color is formed. After the formation regions of the EL layers 1 of the respective colors are divided by the partition walls 9, the EL layers 1 of the respective colors are formed by applying, for example, an application liquid for forming an EL layer of each color. Thereafter, the electrode 11 is formed so as to cover the whole, and thereafter, for example, a protective layer 8 such as SiON having gas barrier properties is formed on each EL layer 1. These electrodes may be formed by an active matrix method or a simple matrix method.

<Adhesive layer>
In the EL element according to the present invention, the above-described EL layer 1 and the optical member group (circularly polarized light separating layer 4, light shielding layer 5 and the like) laminated on the substrate 7 on the viewing side are bonded via the adhesive layer 10. Yes. Examples of the material for forming the adhesive layer 10 include resin materials such as ultraviolet curable acrylates and epoxy resins.

<Circularly polarized light separation layer>
The circularly polarized light separating layer can be formed of a material that transmits one circularly polarized light and reflects the other circularly polarized light. Most preferably, it is formed from cholesteric liquid crystal. As the circularly polarized light separating layer material used in the present invention, chiral nematic liquid crystal or cholesteric liquid crystal can be used. Such a material is not particularly limited as long as it is a polymerizable liquid crystal material capable of forming a liquid crystal phase having cholesteric regularity. This is preferable in that the characteristics can be stabilized.

As an example of the polymerizable liquid crystal material, for example, a compound represented by the following general formula (1) and a compound group shown below can be given. In these compound groups, it is also possible to use a mixture of two or more compounds included in the general formula (1).

In the general formula (1), R ¹ and R ² each represent hydrogen or a methyl group, but both R ¹ and R ² are preferably hydrogen because of the wide temperature range showing the liquid crystal phase. X may be any of hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, and a nitro group, but is preferably a chlorine or methyl group. Further, a and b indicating the chain length of the (meth) acryloyloxy group at both ends of the molecular chain and the alkylene group as a spacer with the aromatic ring can independently take any integer in the range of 2 to 12, A range of 4 to 10 is preferable, and a range of 6 to 9 is more preferable. The compound of the general formula (1) in which a = b = 0 is poor in stability, easily subjected to hydrolysis, and the compound itself has high crystallinity. In addition, the compound of the general formula (1) in which a and b are each 13 or more has a low isotropic transition temperature (TI). For this reason, both of these compounds are not preferred because the temperature range showing liquid crystallinity is narrow.

  Although the example of the polymerizable liquid crystal monomer has been described above, in the present invention, it is also possible to use a polymerizable liquid crystal oligomer, a polymerizable liquid crystal polymer, or the like. As such a polymerizable liquid crystal oligomer and a polymerizable liquid crystal polymer, those conventionally proposed can be appropriately selected and used.

  In the present invention, a chiral nematic liquid crystal having a cholesteric regularity in which a chiral agent is added to the nematic liquid crystal can also be suitably used. The chiral agent is a molecular compound having an optically active site, and the chiral agent is mainly used for the purpose of inducing a helical pitch in the positive uniaxial nematic regularity expressed by the above-described compound. As long as this object is achieved, a desired helical pitch can be induced without compromising the liquid crystallinity of the polymerizable liquid crystal material which is compatible with the above compound in a solution state or a molten state and can take the nematic regularity. If it is a thing, the kind of low molecular compound as a chiral agent shown below will not be specifically limited, However, It is preferable when obtaining the optical element with favorable heat resistance that there exists a polymerizable functional group in the both terminal of a molecule | numerator. It is essential that the chiral agent used for inducing a helical pitch in the liquid crystal has at least some chirality in the molecule. Accordingly, the chiral agent that can be used in the present invention includes, for example, a compound having one or more asymmetric carbons, a compound having an asymmetric point on a heteroatom such as a chiral amine, a chiral sulfoxide, Alternatively, compounds having axial asymmetry such as cumulene and binaphthol can be exemplified. More specifically, commercially available chiral nematic liquid crystal, for example, S-811 (manufactured by Merck) and the like can be mentioned.

  The amount of the chiral agent blended in the polymerizable liquid crystal material of the present invention is determined in consideration of the helical pitch inducing ability and the cholesteric property of the finally obtained polarization selective reflection layer. Specifically, although it varies greatly depending on the polymerizable liquid crystal material to be used, 0.01 to 60 parts by weight, preferably 0.1 to 40 parts by weight, more preferably 100 parts by weight of the total amount of the polymerizable liquid crystal material. Is selected in the range of 0.5 to 30 parts by weight, most preferably 1 to 20 parts by weight.

  In the present invention, it is not essential that such a chiral agent has polymerizability. However, in consideration of the thermal stability and the like of the obtained optical functional layer, it is preferable to use a polymerizable chiral agent that can be polymerized with the above-described polymerizable liquid crystal material and fix the cholesteric regularity. In particular, it is preferable to have a polymerizable functional group at both ends of the molecule in order to obtain an optical element having good heat resistance.

  Next, a method for forming a circularly polarized light separating layer will be described. A layer having a cholesteric liquid crystal property as a circularly polarized light separation layer needs to be fixed to a support or the like, but there are three steps of fixing, that is, polymerizing, coating, alignment treatment, and curing.

  First, the coating process will be described. The liquid crystal material can be applied as it is, but it is desirable to make it into an ink by dissolving it in a solvent such as an organic solvent in order to match the viscosity with the coating apparatus and to obtain a good liquid crystal alignment state. The solvent is not particularly limited as long as it can dissolve the liquid crystal material, but a solvent that does not erode the base material is preferable. Specific examples include acetone, 3-methoxybutyl acetate, diglyme, cyclohexanone, tetrahydrofuran, toluene, xylene, chlorobenzene, methylene chloride, and methyl ethyl ketone. The degree of dilution of the liquid crystal material is not particularly limited, but it should be diluted to 5 to 50%, more preferably 10 to 30%, considering that the liquid crystal itself is a material with low solubility and high viscosity. Good.

  As a coating method, a known technique can be used. Specifically, the liquid crystal material can be applied onto the substrate by a roll coating method, a gravure coating method, a bar coating method, a slide coating method, a die coating method, a slit coating method, a dipping method, or the like. When a plastic film is used, film coating with a roll-to-roll can be performed.

  Next, when a material containing a solvent is applied, the liquid crystal material is held at a predetermined temperature at which a cholesteric liquid crystal structure (hereinafter, the state of the liquid crystal structure before curing is referred to as a liquid crystal phase) is selected and polarization selection is performed. It is necessary to provide a reflection function. In this state, the liquid crystal phase is fixed. The alignment treatment is usually performed together with a drying process for removing the solvent. In order to remove the solvent, a drying temperature of 40 to 120 ° C., preferably 60 to 100 ° C. is suitable, and the cholesteric liquid crystal alignment is expressed during the drying time, and the solvent may be substantially removed. A range of 600 seconds, more preferably 30 to 180 seconds is preferable. If the orientation is still insufficient after drying, the heating time is appropriately extended. If vacuum drying is used for the drying process, it is desirable to provide a heating time for the alignment treatment separately.

  Here, the alignment state of the cholesteric liquid crystal will be described. The cholesteric liquid crystal phase is manifested by the liquid crystal molecules having a helical structure, but as with the mirror surface obtained by depositing on the alignment film, the helical structure can be constructed even in the diffusion state where the helical axis that does not require the alignment film is not in a certain direction. (This alignment does not mean that the molecular axes are aligned in the rubbing direction on the alignment film, but means self-assembly of the cholesteric liquid crystal itself). Therefore, the alignment process is required under film formation conditions where the rubbing process is not performed. The reflection directivity of the cholesteric layer can be controlled in the state of cholesteric molecular arrangement. When the cholesteric layer is formed on the alignment film, it becomes planar alignment, and the helical axis is aligned perpendicular to the surface direction. As a result, selective reflection becomes specular reflection. On the other hand, in the case of imparting diffusibility, it is not necessary to use an alignment film, and it is obtained by directly forming a film on the surface of a resin film not subjected to an alignment process such as a general rubbing process. As another method, disturbance of the helical axis can be induced also by the material composition, and a method of adding an additive such as a surfactant can be mentioned. By disturbing the helical axis, cholesteric reflection and diffuse reflection can be achieved.

  Next, a method for curing the liquid crystal phase will be described. The curing method includes a method by solvent drying, a method by heating and radiation irradiation, or a combination thereof. First, a method by solvent drying will be described. In the case of a polymer liquid crystal material, it is possible to fix the liquid crystal by dissolving it in an organic solvent or the like to form a solution, applying it to a substrate, and then removing the solvent by drying. In this case, if the solvent removal is completed, the liquid crystal material can form a solidified thin film having a cholesteric orientation. The solvent type, drying conditions, etc. are as described above.

  Next, thermal polymerization will be described. In the case of heating, the molecular bonding state generally changes depending on the heating (baking) temperature. Therefore, if there is temperature unevenness in the liquid crystal layer surface during heating, physical properties such as film hardness and optical characteristics will also be uneven. In order to keep the film hardness distribution within ± 10%, it is preferable to suppress the heating temperature distribution within ± 5%. Further, it is preferably within ± 2%. As a method of heating, a close contact or a slight space may be provided on the hot plate and held so as to be parallel to the plate. Moreover, it may be a method of standing or passing while heating an entire space such as an oven, and there is no particular limitation as long as the uniformity of the heating temperature is obtained. When using a film coater or the like, it is desirable that the drying zone is long and the heating time is sufficient. In the case of heating, it is generally necessary to maintain a high temperature of 100 ° C. or higher, but it is generally from about 150 ° C. to the heat resistance of the substrate. In particular, if the film substrate is excellent in heat resistance, high-temperature heating at 150 ° C. or higher is also possible.

  Next, polymerization by radiation irradiation will be described. In the case of curing by radiation irradiation, the liquid crystal is fixed by photopolymerization reaction by radiation irradiation. Specifically, electron beams and ultraviolet rays (250 to 400 nm) are often used as the radiation, and in the case of ultraviolet curing, it is desirable to add a photopolymerization initiator. Photopolymerization initiators are benzyl (also called bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-benzoyl-4'-methyldiphenyl sulfide, benzyl methyl ketal, dimethylaminomethyl Benzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, methylobenzoyl formate, 2-methyl-1- (4- (Methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-dodecylphenyl)- 2-hydroxy 2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane Examples include -1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, and the like. In addition, a sensitizer can be added in addition to the photopolymerization initiator as long as the object of the present invention is not impaired.

  The addition amount of such a photopolymerization initiator is generally 0.01 to 20% by mass, preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass. Can be added to the liquid crystalline material.

  The cholesteric layer is laminated by the above-described film forming method or a combination thereof. If the lower cholesteric layer is fixed, the next layer can be applied in the same manner as the film formation method. When the cholesteric liquid crystal is applied to the surface of the cholesteric liquid crystal layer in the diffusion state, the alignment state of the lower layer is continued, so there is no need to provide a layer for controlling the alignment between the cholesteric layers. It is also possible to provide an adhesive layer.

  The film thickness of the cholesteric layer can be appropriately selected so that the circularly polarized light separating layer has a desired reflectance. The reflectance is preferably 70% or more, more preferably 90% or more. When light is repeatedly reflected between the circularly polarized light separating layer and the reflective electrode, the light use efficiency can be further improved by setting the selective reflectance of the circularly polarized light separating layer to 70% or more. The reflectance depends on the number of helical pitches, that is, depends on the thickness of the circularly polarized light separating layer. Specifically, in order to obtain 100% reflectivity, it is said that about 4 to 8 pitches are required. Therefore, although it depends on the type of material and the selective reflection wavelength, it is a film of 1 to 10 μm in one color layer. Thickness is necessary. On the other hand, the thicker the thickness, the better. It is not preferable, and if it is too thick, the orientation cannot be controlled or unevenness occurs, or the light absorption of the material itself increases, so the above range is appropriate.

  In addition to the cholesteric liquid crystal, a means for obtaining a circularly polarized light separating layer may be a combination of a linearly polarized light separating layer and a quarter wavelength retardation layer. By adopting a configuration in which the linearly polarized light separating layer is sandwiched between two quarter-wave retardation layers, the optical behavior is equivalent to that of the cholesteric liquid crystal. The linearly polarized light separating layer is not particularly limited as long as it has a property of transmitting one linearly polarized light and reflecting the other linearly polarized light orthogonal thereto, and examples thereof include DBEF manufactured by 3M. The quarter wavelength retardation layer may be generally used in a liquid crystal display device and is not particularly limited as long as it can convert linearly polarized light into circularly polarized light. In addition, a broadband 1/4 wavelength phase difference layer that converts linearly polarized light into circularly polarized light with respect to the entire visible light region is preferable.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not construed as being limited to the following examples.

Example 1
Preparation of circularly polarized light separation layer Prepare cholesteric liquid crystal solution 1 with 5% photopolymerization initiator Irg907 (manufactured by Ciba Geigy) dissolved in cyclohexanone in a monomer-mixed liquid crystal with a chiral agent added to a UV-curable nematic liquid crystal did. This liquid crystal solution 1 had a central wavelength of selective reflection at 445 nm. Further, a liquid crystal solution 2 was prepared in the same manner as described above except that the addition amount of the chiral agent was changed so that the selective reflection center wavelength was 510 nm. Further, a liquid crystal solution 3 was prepared in the same manner as described above except that the addition amount of the chiral agent was changed so that the selective reflection center wavelength was 625 nm.

The liquid crystal solution 1 obtained above was applied by spin coating on a substrate 1 on which an alignment film (AL1254, manufactured by JSR) was formed on a glass substrate (Corning Corp., 1737 material). Thereafter, drying and alignment treatment were carried out in an oven at 80 ° C. for 90 seconds to obtain a cholesteric liquid crystal film from which the solvent was removed. Next, the liquid crystal film was irradiated with ultraviolet rays (500 mJ / cm ² ) in a nitrogen atmosphere and cured to obtain a first polarization selective reflection layer having blue selective reflection.

  Next, the liquid crystal solution 2 is directly applied on the polarization selective reflection layer formed as described above by the same method as that for the first layer, followed by drying, orientation, and curing treatment. A polarization selective reflection layer having a green selective reflection was laminated. Next, in the same manner as described above, a polarization selective reflection layer having a red selective reflection of the third layer was laminated using the liquid crystal solution 3.

  Thereafter, the substrate on which the three polarization selective reflection layers were laminated was post-baked (fired) at 230 ° C. for 60 minutes. In this manner, a circularly polarized light separation layer having a polarization selective reflection function including selective reflection wavelengths of 445 nm, 510 nm, and 625 nm was formed. The thickness of each layer was 3 μm for the first layer, 4 μm for the second layer, and 5 μm for the third layer.

  This circularly polarized light separating layer transmits the left circularly polarized light component and reflects the right circularly polarized light component in light having selective reflection wavelengths of 445 nm, 510 nm, and 625 nm. The reflectance at each selective reflection peak wavelength (the reflectance when only the right circularly polarized light component was incident at 100) was 90%.

Formation of EL Element Next, a light shielding layer and a colored layer were formed on the circularly polarized light separating layer obtained as described above. On the circularly polarized light separating layer substrate, first, a light shielding layer was formed so that a vertical and horizontal pattern was a lattice pattern in plan view. This light-shielding layer is formed in a predetermined pattern by applying the following light-shielding layer photoresist on the circularly polarized light separating layer by spin coating and pre-baking (pre-baking) at 90 ° C. for 3 minutes. The film was exposed by using a mask (100 mJ / cm ² ), followed by spray development using a 0.05% KOH aqueous solution for 60 seconds, followed by post-baking (baking) at 200 ° C. for 60 minutes. did. The thickness of the light shielding layer was 1.2 μm. At this time, the aperture ratio of the light shielding layer was set to 30%.

<Photoresist for light shielding layer>
・ Black pigment (manufactured by Dainichi Seika Kogyo Co., Ltd., TM Black # 95550) 14.0 parts by weight ・ Dispersant (Bic Chemie Co., Ltd., Disperbyk 111) 1.2 parts by weight ・ Polymer (produced by Showa Polymer Co., Ltd.) , VR60) 2.8 parts by weight Monomer (Sartomer Co., Ltd., SR399) 3.5 parts by weight Additive (Soken Chemical Co., Ltd., L-20) 0.7 parts by weight Initiator (2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1) 1.6 parts by weight Initiator 1 (4,4′-diethylaminobenzophenone) 0.3 part by weight Initiator 2 (2 , 4-diethylthioxanthone) 0.1 part by weight ・ Solvent (ethylene glycol monobutyl ether) 75.8 parts by weight Beads are added to the dispersion composition composed of the above black pigment, dispersant and solvent, and dispersed in a disperser for 3 hours. Let Then, the dispersion from which the beads were removed and the above-described polymer, monomer, additive, initiators 1 to 3 and a clear resist composition comprising a solvent were mixed to prepare a pigment-dispersed light shielding layer photoresist. In addition, a paint shaker (manufactured by Asada Tekko Co., Ltd.) was used as the disperser (the same applies to the respective color pattern forming photoresists below).

Next, a colored layer was formed on the light shielding layer. This colored layer is prepared by adjusting the following red, green, and blue color pattern forming photoresists, and then, first, forming a red pattern forming pigment-dispersed photoresist on the transparent substrate 1 on which the light shielding layer is formed. It was applied by a spin coating method, pre-baked (pre-baked) at 80 ° C. for 5 minutes, and exposed to ultraviolet rays (300 mJ / cm ² ) using a photomask for a predetermined coloring pattern corresponding to a red color pattern. Next, spray development using a 0.1% KOH aqueous solution was performed for 60 seconds, followed by post-baking (baking) at 200 ° C. for 60 minutes, and a film thickness of 1. A 1 μm red colored layer was formed in a strip pattern.

  Subsequently, using a pigment-dispersed photoresist for forming a green pattern, the same method as described above is repeated, and the film is placed at a predetermined position with respect to the formation pattern of the light shielding layer and the red colored layer formed in a predetermined pattern. A green colored layer having a thickness of 1.1 μm was formed in a strip pattern. Further, a blue colored layer having a thickness of 1.7 μm is formed in a strip pattern by the same method as described above except that a pigment photoresist for forming a blue pattern is used and the post-bake condition is changed to 170 ° C. × 30 minutes. Formed. At this time, the peak transmittance of each color was adjusted to 90%.

<Pigment-dispersed photoresist for red pattern formation>
Red pigment (CIPR 254 (Ciba Specialty Chemicals, chromophthal DPP Red BP)) 4.8 parts by weight Yellow pigment (CI PY139 (BASF, Pariotol Yellow D1819))
1.2 parts by weight Dispersant (manufactured by Zeneca Corp., Solsperse 24000) 3.0 parts by weight Monomer (Sartomer Co., Ltd., SR399) 4.0 parts by weight Polymer 1 5.0 parts by weight Initiator 1 (Ciba Geigy, Irgacure 907) 1.4 parts by weight Initiator 2 (2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-bi Imidazole) 0.6 parts by weight Solvent (propylene glycol monomethyl ether acetate) 80.0 parts by weight The above polymer 1 is benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate = 15.6: 37.0: Addition of 16.9 mol% of 2-methacryloyloxyethyl isocyanate to 100 mol% of the copolymer of 30.5: 16.9 (molar ratio) Are as hereinbefore, the weight average molecular weight is 42500.

  Add the beads to the dispersion composition consisting of the above red pigment, yellow pigment, dispersant and solvent, disperse with a disperser for 3 hours, and then remove the beads and the above polymer, monomer, additive, start Agents 1 and 2 and a clear resist composition comprising a solvent were mixed to prepare a pigment-dispersed photoresist for forming a red pattern.

<Pigment-dispersed photoresist for green pattern formation>
Green pigment (CI PG7 (manufactured by Dainichi Seika, Seika Fast Green 5316P))
3.7 parts by weight-Yellow pigment (CI PY139 (manufactured by BASF, Pariotor Yellow D1819))
2.3 parts by weight Dispersant (manufactured by Zeneca Corp., Solsperse 24000) 3.0 parts by weight Monomer (Sartomer Co., Ltd., SR399) 4.0 parts by weight Polymer 1 5.0 parts by weight Initiator 1 (Ciba Geigy, Irgacure 907) 1.4 parts by weight Initiator 2 (2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-bi Imidazole) 0.6 parts by weight Solvent (propylene glycol monomethyl ether acetate) 80.0 parts by weight The above polymer 1 is benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate = 15.6: 37.0: 30. 5: 16.9 mol% of 2-methacryloyloxyethyl isocyanate was added to 100 mol% of a copolymer of 16.9 (molar ratio). And the weight average molecular weight of 42500.

  Add the beads to the dispersion composition consisting of the above green pigment, yellow pigment, dispersant and solvent, disperse with a disperser for 3 hours, and then remove the beads and the above polymer, monomer, additive, start Agents 1 and 2 and a clear resist composition comprising a solvent were mixed to prepare a pigment-dispersed green pattern forming photoresist.

<Pigment-dispersed photoresist for blue pattern formation>
Blue pigment (CI PB15: 6 (phthalocyanine dye, Heliogen Blue L6700F manufactured by BASF)) 4.6 parts by weight Purple pigment (CIPV23 (dioxazine dye, Foster, manufactured by Clariant) Palm RL-NF)) 1.4 parts by weight Pigment derivative (manufactured by Zeneca Corp., Solsperse 12000) 0.6 parts by weight Dispersant (Zeneca Corp., Solsperse 24000) 2.4 parts by weight Monomer ( Sartomer Co., Ltd., SR399) 4.0 parts by weight Polymer 1 5.0 parts by weight Initiator 1 (Ciba Geigy, Irgacure 907) 1.4 parts by weight Initiator 2 (2,2'-bis ( o-Chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole) 0.6 parts by weight Solvent (propylene glycol monomethyl ether Tate) 80.0 parts by weight The above polymer 1 is a copolymer 100 of benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate = 15.6: 37.0: 30.5: 16.9 (molar ratio). 2-Methacryloyloxyethyl isocyanate is added 16.9 mol% with respect to mol%, and the weight average molecular weight is 42500.

  The above materials were mixed and dissolved to prepare a pigment dispersed photoresist for a blue layer.

  Next, a transparent protective layer was provided on each colored layer of the substrate 1 on which a circularly polarized light separating layer, a light shielding layer, and red, green, and blue colored layers were sequentially laminated. As this transparent protective layer, a photoresist (made by JSR, trade name: JNPC80), which is an ultraviolet curable resin, is applied on each colored layer and then irradiated with ultraviolet rays so as to have a thickness of 1.5 μm. A film was formed.

Formation of Organic EL Light Emitter Next, as the base material 2, a non-alkali glass substrate having a thickness of 1.7 mm having TFTs as switching elements was prepared. On the non-alkali glass substrate, a reflective anode having a thickness of 140 nm composed of a laminated structure of ITO (20 nm) / Ag (100 nm) / ITO (20 nm) was formed in a predetermined pattern. The reflectance of this reflective electrode was 53%.

  Next, a partition made of a positive resist is formed for dividing each EL layer, and subsequently, an EL layer (R, G, B) of each color having a predetermined pattern is sequentially formed, and further, a thickness of 10 nm made of MgAg. The semi-transparent cathode and a protective film made of SiON and having a thickness of 100 nm were sequentially formed and laminated to prepare an organic EL light emitting device having a three-color coating type EL layer. At this time, the ratio of the light-emitting area and the non-light-emitting area of the light emitter in plan view was set to light-emitting area: non-light-emitting area = 3: 7.

Each color EL layer was prepared as follows. First, each color common layer has a thickness of 40 nm made of a co-deposited thin film of bis (N- (1-naphthyl-N-phenyl) benzidine) (α-NPD) and MoO ₃ (volume concentration of MoO ₃ : 20%). A hole injection layer and a 20 nm thick hole transport layer made of α-NPD were formed between the partition walls. Thereafter, 4,4-N, N′-dicarbazole-biphenyl (CBP) is used as the host material for the red EL layer, and tris (1-phenylisoquinoline) iridium (III) complex (Ir (piq) ₃ is used as the guest material. ), A red EL layer R having a thickness of 40 nm is formed in a predetermined pattern, and 4,4-N, N′-dicarbazole-biphenyl (CBP) is used as a host material for the green EL layer and a guest material A tris (2-phenylpyridine) iridium (III) complex (Ir (ppy) ₃ ) is used as a green EL layer G having a thickness of 40 nm and formed in a predetermined pattern. , 10-di-2-naphthylanthracene (DNA) and 1-tert-butyl-perylene (TBP) as guest material Was to form a blue EL layer B with a thickness of 40nm in a predetermined pattern forming each EL layer.

  Next, an electron transport layer made of tris (8-quinolinolato) aluminum complex (Alq3) having a thickness of 20 nm and an electron injection layer made of LiF having a thickness of 0.5 nm were sequentially patterned to form EL layers (R, G, B) were formed. In each of the above EL layers, the mixing ratio of the host material and the guest material was adjusted so that all of the red EL layer, the green EL layer, and the blue EL layer were 20: 1.

  The luminance of light emitted from each EL layer was measured using a spectroradiometer (model name: SR-2) manufactured by Topcon Corporation. The peak top of each color was 445 nm for the blue EL layer, 510 nm for the green EL layer, and 625 nm for the red EL layer.

  The base material 1 provided with the obtained circularly polarized light separating layer, the light shielding layer and the colored layer, and the base material 2 provided with the organic EL luminescent material obtained above were bonded to an adhesive (trade name: NT-01UV, Nitto). And a circularly polarizing plate was bonded to the viewing side of the base material 1 (the side opposite to the bonding surface of the base material 2) to produce an organic EL element. At this time, the lattice pattern of the light-shielding layer and the pattern of the non-light-emitting area of the organic EL light emitter are almost the same, the patterns are aligned and pasted, and most of the light of the organic EL light emitter passes through the opening of the light-shielding layer. I was able to do it.

Example 2
An organic EL device including a light shielding layer and a circularly polarized light separating layer was produced in the same manner as in Example 1 except that the colored layer was not formed.

Example 3
Moreover, in Example 1, after forming the light shielding layer and the colored layer on the base material 1 first, and then forming the circularly polarized light separating layer on the colored layer, the organic EL element was fabricated in the same manner as in Example 1. Produced.

Comparative Example 1
An organic EL device was produced in the same manner as in Example 1 except that the light shielding layer and the colored layer were not formed.

Comparative Example 2
An organic EL device was produced in the same manner as in Example 1 except that the circularly polarized light separating layer, the light shielding layer and the colored layer were not formed.

In the organic EL elements of Evaluation Test Examples 1 to 3 and Comparative Examples 1 and 2, the contrast in the bright room and the appearance of the video were evaluated. The measurement environment was a bright room of about 600 lx, which is equivalent to a normal office under a fluorescent lamp, and each EL display was arranged perpendicular to the floor. Fluorescent lighting was placed on the ceiling. Contrast is measured using a luminance meter (CS-100A, manufactured by Minolta) to measure the brightness of the organic EL element when displaying white in a bright room and the brightness of the organic EL element when displaying black in a bright room. The white display latitude / black display brightness was calculated. Luminance was measured from the front of the display in the vertical direction. The results were as shown in Table 1.

  As is clear from the results of Table 1, the brightness of white display in Example 1 is 1.2 times that in Comparative Example 2, and Example 2 is 1.5 times that in Comparative Example 2. Yes, Example 3 was 1.3 times that of Comparative Example 2, and an improvement in luminance was confirmed, and an improvement in light utilization efficiency was observed.

  Contrast was 1.2 times in Examples 1 to 3 with respect to Comparative Example 2, and 1.8 times with respect to Comparative Example 1, and a dramatic improvement in contrast was observed.

  As for the appearance of the images, Examples 1 to 3 were clearly visible and vividly visible even in a bright environment as compared with Comparative Examples 1 and 2. Furthermore, in Example 1, the change in perspective color due to external light was also improved.

  Furthermore, in the organic EL element of Example 1, the aperture ratio of the light shielding layer was adjusted to 20%, 40%, and 60%, and the peak transmittance of each color of the colored layer was adjusted to be 80%, 60%, and 40%. Each was made.

  In addition, the organic EL element of Example 3 was prepared in the same manner as described above, with the aperture ratio of the light shielding layer and the peak transmittance of the colored layer varied.

  About each obtained organic EL element, sensory evaluation was performed about the clarity of the image | video in a bright room. The evaluation environment was a bright room of about 600 lx, which is the same as a normal office under a fluorescent lamp, and each EL display was arranged perpendicular to the floor. Fluorescent lighting was placed on the ceiling.

The evaluation criteria were as follows.
A: Remarkably clear as compared with the organic EL element of Comparative Example 1. B: Clearly clear as compared with the organic EL element of Comparative Example 1. Δ: Slightly compared with the organic EL element of Comparative Example 1. *: The organic EL element of Comparative Example 1 is clearer.

The evaluation results were as shown in Table 2 below.

  For the organic EL element of Example 3, the aperture ratio of the light shielding layer was set to 20%, 40%, and 60% as described above, and the peak transmittance of each color of the colored layer was 80%, 60%, and 40%. Each of these was prepared and evaluated in the same manner.

  As a result, the same result as that of the organic EL element of Example 1 was obtained.

The schematic sectional drawing of the EL element by this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The schematic sectional drawing of the EL element by the preferable aspect of this invention is shown. The reflection profile of the narrow-band reflective circularly polarized light separating layer used in the present invention is shown. 2 shows a reflection profile of a broadband reflective circularly polarized light separating layer used in the present invention. The reflection profile of the narrow-band reflective circularly polarized light separating layer used in the present invention is shown. 2 shows a reflection profile of a broadband reflective circularly polarized light separating layer used in the present invention. The reflection characteristic of the circularly polarized light separating layer having specular reflectivity used in the present invention is shown. The reflection characteristic of the circularly polarized light separating layer having diffuse reflection used in the present invention is shown. The reflection characteristics of the circularly polarized light separating layer having sandwich diffuse reflection used in the present invention are shown. The schematic sectional drawing of the conventional EL element which does not have a circularly polarized light separation layer is shown. The schematic sectional drawing of the conventional EL element which does not have a light shielding layer is shown.

Explanation of symbols

1. 1. EL layer 2. Circularly polarizing plate Reflective electrode layer (reflective layer)
4). 4. Circularly polarized light separating layer Light shielding layers 6, 7. Base material 8. Protective layer 9. Septum 10. Adhesive layer 11. Transparent electrode 12. Colored layer

Claims (25)

An electroluminescent layer in which a plurality of light emitting regions are arranged in a pixel shape, a circularly polarizing plate provided on the viewing side of the electroluminescent layer, and provided on the opposite side of the viewing side of the electroluminescent layer An optical member used for an electroluminescent device comprising:
Comprising a circularly polarized light separating layer and a light shielding layer,
The optical member, wherein the circularly polarized light separating layer and the light shielding layer are disposed between the circularly polarizing plate and the electroluminescent layer.   The optical member according to claim 1, wherein the circularly polarized light separating layer and the light shielding layer are laminated in the order of the circularly polarized light separating layer and the light shielding layer from the viewing side.   The optical member according to claim 1, wherein the circularly polarized light separating layer and the light shielding layer are laminated in the order of the light shielding layer and the circularly polarized light separating layer from the viewing side.   The optical member according to claim 1, wherein the light shielding layer is patterned so as to correspond to a non-light emitting region of the electroluminescent layer.   The optical member according to claim 1, wherein the circularly polarized light separating layer is patterned so as to correspond to a light emitting region of the electroluminescent layer.   The electroluminescent device according to claim 1, wherein the circularly polarized light separating layer is a narrow-band reflective layer having a reflection peak wavelength corresponding to each emission wavelength region of the electroluminescent layer.   The circularly polarized light separating layer is a narrowband reflecting layer having a reflection peak wavelength shorter than a blue emission peak wavelength from the electroluminescent layer when the emission wavelength region of the electroluminescent layer is blue. The optical member according to claim 6, wherein there is an optical member.   The circularly polarized light separation layer is a narrowband reflection layer having a reflection peak wavelength longer than the red emission peak wavelength from the electroluminescent layer when the emission wavelength region of the electroluminescent layer is red. The optical member according to claim 6, wherein there is an optical member.   The optical member according to claim 1, wherein the circularly polarized light separating layer is a broadband reflective layer having a reflective band corresponding to the entire emission wavelength region of the electroluminescent layer.   The optical member according to claim 1, wherein the circularly polarized light separating layer has specular reflectivity.   The optical member according to any one of claims 1 to 9, wherein the circularly polarized light separating layer has diffuse reflectivity capable of substantially maintaining a polarization state of reflected light. The optical member according to claim 11, wherein the circularly polarized light separating layer has narrow diffuse reflectivity.   The optical member according to any one of claims 1 to 12, wherein the circularly polarized light separating layer is formed of a cholesteric liquid crystal.   A color filter comprising: the optical member according to any one of claims 1 to 13; and a colored layer that transmits a wavelength of light from a light emitting region of the electroluminescent layer.   The color filter according to claim 14, wherein the colored layer is provided in a non-light-shielding region of the patterned light-shielding layer.   The color filter according to claim 14 or 15, wherein an aperture ratio of the light shielding layer is 40% or less.   The color filter of Claim 16 whose transmittance | permeability of the wavelength of the light from the light emission area | region of the said electroluminescent layer of the said colored layer is 80 to 100%.   When the aperture ratio of the said light shielding layer is 20% or less, the transmittance | permeability of the wavelength of the light from the light emission area | region of the said electroluminescent layer of the said colored layer is 60 to 100%. Color filter.   The color filter according to claim 14, wherein the circularly polarized light separation layer is a narrow band reflection layer having a reflection peak wavelength corresponding to each transmission wavelength region of the colored layer.   The circularly polarized light separating layer is a narrow-band reflective layer having a reflection peak wavelength shorter than a blue transmission peak wavelength of the colored layer when the transmission wavelength region of the colored layer is blue. The color filter described.   The circularly polarized light separating layer is a narrow-band reflective layer having a reflection peak wavelength longer than a red transmission peak wavelength of the colored layer when the transmission wavelength region of the colored layer is red. The color filter described.   The color filter according to claim 14, wherein the circularly polarized light separation layer is a broadband reflection layer having a reflection band corresponding to a wavelength range including all transmission wavelength ranges of the colored layer.   An electroluminescent layer in which a plurality of light emitting regions are arranged in a pixel shape, a circularly polarizing plate provided on the viewing side of the electroluminescent layer, and provided on the opposite side of the viewing side of the electroluminescent layer The electroluminescent element provided with the obtained light reflection layer and the optical member as described in any one of Claims 1-13.   The electroluminescent device according to claim 23, wherein the electroluminescent layer comprises a plurality of light emitting regions having different emission wavelengths.   The electroluminescent device according to claim 24, wherein the electroluminescent layer includes a light emitting region that emits white light.

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