Patent Application
20150364721
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2014-120438, filed on Jun. 11, 2014, the entire contents of which are incorporated herein by reference.
The present invention relates to a display device, and specifically to a film structure on the side of a counter substrate facing a substrate on which a light emitting element is provided.
Recently, light-emitting display devices for uses in mobile devices are increasingly strongly desired to have higher definition and consume less power. Examples of display devices for uses in mobile devices are liquid crystal display devices (LCDs), display devices using elements for spontaneously emitting light, for example, organic light-emitting diode (OLED) display devices, electronic paper display devices, and the like.
Organic light-emitting diode display devices and electronic paper display devices, among the above, do not require a backlight unit or a polarization plate, which is required in liquid crystal display devices, and also use a light emitting element driven at a low voltage. For these reasons, these display devices are a target of attention as thin light emitting display devices consuming low power. These display devices can be merely formed of thin films, and thus can be made flexible as described in, for example, Japanese Laid-Open Patent Publication No. 2007-183605. In addition, these display devices do not use a glass substrate, and therefore are lightweight and are not easily breakable. For these reasons, organic light-emitting diode display devices and electronic paper display devices attract a lot of attention. However, it is known as one of the problems of the OLED that the light emitting material used for a light emitting element, for example, an organic light-emitting element located in each of pixels of the OLED, is deteriorated when being exposed to oxygen or moisture and the emission efficiency of the OLED is decreased. Particularly, in a flexible display, because a very thin flexible substrate including a resin material is used, the oxygen and moisture from the exterior reaches to the light emitting material through the flexible substrate. As a result, the light emitting element is deteriorated.
A display device in an embodiment according to the present invention includes a first substrate, a light emitting element located on the first substrate, a second substrate having dampproofness and facing the first substrate, a first barrier layer located on the second substrate and having a higher level of dampproofness than the dampproofness of the second substrate, an organic layer located on the first barrier layer at a position facing the light emitting element, and a second barrier layer located on the organic layer and having a higher level of dampproofness than the dampproofness of the second substrate.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The disclosure is merely exemplary, and alternations and modifications conceivable by a person of ordinary skill in the art without departing from the gist of the present invention are duly encompassed in the scope of the present invention. In the drawings, components may be shown schematically regarding the width, thickness, shape and the like, instead of being shown in accordance with the actual sizes. The drawings are merely exemplary and do not limit the interpretations of the present invention in any way. In the specification and the drawings, components that are substantially the same as those described before bear the identical reference signs thereto, and detailed descriptions thereof may be omitted.
With reference to
The first substrate 100 and the second substrate 200 may be formed of a flexible material. Specifically, the first substrate 100 and the second substrate 200 may be formed of a polyimide resin, an acrylic resin or the like. In this case, the first substrate 100 has a thickness of, preferably, 3 μm or greater and 50 μm or less, and more preferably, 5 μm or greater and 20 μm or less. In a top emission-type display device as in embodiment 1, light released from the light emitting element 110 is output from the side of the second substrate 200. Therefore, the first substrate 100 does not absolutely need to have a high light transmittance. For example, the first substrate 100 may have impurities incorporated thereto in order to have an improved resistance against a heat treatment performed in a step of forming a transistor. Even if the light transmittance of the first substrate 100 is lowered due to the impurities, there is no problem. By contrast, the second substrate 200 is preferably formed of a material having a high light transmittance. In the case of a bottom emission-type display device, light released from a light emitting element is output from the side of a first substrate, and therefore it is preferable that the first substrate is formed of a material having a high light transmittance.
The light emitting element 110 includes a transistor layer and a light emitting layer. The transistor layer includes a transistor element and a line. The transistor element may be an amorphous silicon transistor element, a polysilicon transistor element, a single crystalline silicon transistor element, an oxide semiconductor transistor element, an organic semiconductor transistor element, or the like. The light emitting element 110 does not absolutely need to include a transistor element. For example, the line and the light emitting layer may be provided on the first substrate 100 as in a passive light emitting device. The light emitting layer may be formed of an organic EL layer or an inorganic EL layer. The above-described light emitting layer that is of a spontaneous light emitting type may be replaced with a reflective display layer such as in an electronic paper display device.
The light emitting element 110 may include an underlying barrier layer located between the first substrate 100 and the transistor layer. The underlying barrier layer suppresses impurities from the first substrate 100 or moisture entering from the side of the first substrate 100, from diffusing into the transistor layer or the light emitting layer. The underlying barrier layer may be formed of a silicon nitride film (SiNx film), a silicon oxide film (SiOx film), a silicon nitride oxide film (SiNxOy film), a silicon oxide nitride film (SiOxNy film), an aluminum nitride film (AlNx film), an aluminum oxide film (AlOx film), an aluminum nitride oxide film (AlNxOy film), an aluminum oxide nitride film (AlOxNy film) or the like (x and y each represent an arbitrary numeral figure). The underlying barrier layer may be formed of a stack of such films. The “silicon nitride oxide film” is a silicon nitride film containing oxygen in an amount smaller than that of nitrogen. The “silicon oxide nitride film” is a silicon oxide film containing nitrogen in an amount smaller than that of oxygen.
The first barrier layer 210 may have a single film structure or a stacked film structure. The first barrier layer 210 includes a first damp-proof film containing silicon and nitrogen and having a higher level of dampproofness than the dampproofness of the second substrate 200. In the case where the first barrier layer 210 has a single film structure, the first damp-proof film is the first barrier layer 210. In the case where the first barrier layer 210 has a stacked film structure, at least one of the films included in the first barrier layer 210 is the first damp-proof film. The first damp-proof film may be an SiNx film, an SiNxOy film, or a such a film containing impurities. Alternatively, the first damp-proof film may be an AlNx film, an AlNxOy film, any other metal nitride film, or any other metal nitride oxide film.
The second barrier layer 230 may have a single film structure or a stacked film structure. The second barrier layer 230 includes a second damp-proof film containing silicon and nitrogen and having a higher level of dampproofness than the dampproofness of the second substrate 200. In the case where the second barrier layer 230 has a single film structure, the second damp-proof film is the second barrier layer 230. In the case where the second barrier layer 230 has a stacked film structure, at least one of the films included in the second barrier layer 230 is the second damp-proof film. The second damp-proof film may be an SiNx film, an SiNxOy film, or a such a film containing impurities. Alternatively, the second damp-proof film may be an AlNx film, an AlNxOy film, any other metal nitride film, or any other metal nitride oxide film. The second damp-proof film may have a higher level of dampproofness than the dampproofness of the organic layer 220 to have a block function against moisture and gas released from the organic layer 220.
The first damp-proof film and the second damp-proof film each preferably have a thickness of 50 nm or greater in order to have a sufficient barrier property against moisture. The first damp-proof film and the second damp-proof film represented by an SiNx film have a very high stress, and therefore, each preferably have a thickness of 500 nm or less. The first damp-proof film of the first barrier layer 210 and the second damp-proof film of the second barrier layer 230 may be formed of the same material or different materials.
The organic layer 220 may be a color filter that transmits light of a specific wavelength band. The color filter is located in correspondence with each of pixels provided in a display area of the display device 10. The organic layer 220 may be a light blocking film located between the pixels and having a light blocking property. The organic layer 220 may act as both of a color filter and a light blocking film.
As described above, the display device 10 in embodiment 1 according to the present invention includes a barrier layer between the second substrate 200 and the organic layer 220 and between the organic layer 220 and the light emitting element 110. Therefore, entrance of moisture from the side of the second substrate 200 is suppressed. As a result, deterioration of the light emitting element 110 is prevented. In addition, moisture or a gas component desorbed from the organic layer 220 is suppressed from reaching the light emitting element 110, and therefore, deterioration of the light emitting element 110 is suppressed.
With reference to
The first substrate 100 includes pixels 180, each including a light emitting element, in a display area 130. In the display device 20 in embodiment 2, each pixel 180 includes a light emitting element. The light emitting element releases white light from a top surface thereof. On the second substrate 200, a light blocking layer 121 and color filters 181 through 183 are provided. The light blocking layer 121 includes openings in correspondence with the pixels 180. The color filters 181 through 183 are provided in correspondence with the openings, and each transmit light of a specific wavelength band. The first substrate 100 and the components provided thereon, and the second substrate 200 and the components provided thereon, are bonded together with a sealing member 150 and a filler 300. The sealing member 150 is located in a peripheral area 140, which is around the display area 130 in which the pixels 180 are located. The filler 300 is provided to fill an area enclosed by the sealing member 150.
The display device 20 also includes the second substrate 200, which is flexible, a first barrier layer 210, the color filters 181, 182 and 183, the light blocking layer 121, and a second barrier layer 230. The first barrier layer 210 is located on the first substrate 200. The first barrier layer 210 has a higher level of dampproofness than that of the second substrate 200. The color filters 181, 182 and 183 are provided in correspondence with the light emitting elements 111, 112 and 113 located in the display area 130. The light blocking layer 121 is located between the color filters 181 through 183. The second barrier layer 230 is located in the display area 130 and the peripheral areal 140 so as to cover the light blocking layer 121 and the color filters 181, 182 and 183, and is in contact with the first barrier layer 210 in the peripheral areal 140 to seal the light blocking layer 121 and the color filters 181 through 183. In this example, the color filters correspond to the three RGB colors. Alternatively, the color filters may correspond to the four RGBW colors including the RGB colors and white, or correspond to four colors including the RGB colors and any other color.
The first substrate 100 and the components provided thereon, and the second substrate 200 and the components provided thereon, are bonded together with the sealing member 150 and the filler 300. The sealing member 150 is in contact with the second barrier layer 230 and the protective layer 120 in the peripheral area 140. The present invention is not limited to having the structure shown in
In
As described above, the display device 20 in embodiment 2 according to the present invention includes a barrier layer between the second substrate 200 and the color filters 181 through 183 and between the color filters 181 through 183 and the light emitting elements 111 through 113. Therefore, entrance of moisture from the side of the second substrate 200 is suppressed. In addition, moisture or a gas component desorbed from the color filters 181 through 183 is suppressed from reaching the light emitting elements 111 through 113, and entrance of moisture from a peripheral area of the display device 20 is suppressed. Therefore, deterioration of the light emitting elements 111 through 113 is prevented.
With reference to
Next, the underlying barrier layer 102 is formed on the first substrate 100. The underlying barrier layer 102 is provided to suppress diffusion, to the transistor layer and the light emitting layer, of impurities from the first substrate 100 and moisture entering from the side of the first substrate 100. The underlying barrier layer 102 may be formed of a material described in embodiment 1. Next, the light emitting elements 111, 112 and 113 each including the transistor layer and the light emitting layer are formed. In a heat treatment performed in a step of forming the underlying barrier layer 102 and the transistor layer, the temperature is desirably lower than the glass transition point of the first substrate 100. Next, the protective layer 120 is formed on the light emitting elements 111, 112 and 113. The protective layer 120 is desirably formed at a temperature lower than the glass transition point of the organic layer included in the light emitting layer in each of the light emitting elements 111, 112 and 113.
Next, the first support substrate 500 and the components provided thereon shown in
In this manner, the flexible display device 20 in embodiment 2 according to the present invention is produced.
With reference to
The first adhesive film 211 and the second adhesive film 213 may each be an SiOx film, an SiOxNy film, or a such a film containing impurities. Alternatively, the first adhesive film 211 and the second adhesive film 213 may each be an AlOx film, an AlOxNy film, any other metal oxide film, or any other metal oxide nitride film. The first damp-proof film 212 has a higher level of dampproofness than that of the first adhesive film 211 and the second adhesive film 213. In the example shown in
As described above, in embodiment 3 according to the present invention, the first adhesive film 211 and the second adhesive film 213 are provided. Even if the adhesiveness between the first damp-proof film 212 and the second substrate 200 or between the first damp-proof film 212 and the organic layer 220 is poor, the structure in embodiment 3 provides both of a high level of adhesiveness and a high level of dampproofness. In the case where, for example, the first damp-proof film 212 is an SiNx film or an SiNxOy film, the first adhesive film 211 provided on the second substrate 200 suppresses the second substrate 200 from being etched by ammonia gas that is used to form the SiNx film or an SiNxOy film.
The third adhesive film 231 may be an SiOx film, an SiOxNy film, or a such a film containing impurities. Alternatively, the third adhesive film 231 may be an AlOx film, an AlOxNy film, any other metal oxide film, or any other metal oxide nitride film.
The second damp-proof film 232 has a higher level of dampproofness than that of the third adhesive film 231.
As described above, in embodiment 3 according to the present invention, the third adhesive film 231 is provided. Even if the adhesiveness between the second damp-proof film 232 and the organic layer 220 is poor, the structure in embodiment 3 provides both of a high level of adhesiveness and a high level of dampproofness. In the case where, for example, the second damp-proof film 232 is an SiNx film or an SiNxOy film, the third adhesive film 231 provided on the organic layer 220 suppresses the organic layer 220 from being etched by ammonia gas that is used to form the SiNx film or an SiNxOy film.
As described above, the display device in embodiment 3 according to the present invention includes the first through third adhesive films 211, 213 and 231 respectively between the first damp-proof film 212 and the second substrate 200, between the first damp-proof film 212 and the organic layer 220, and between the second damp-proof film 232 and the organic layer 220. Therefore, a high level of adhesiveness is provided.
The present invention is not limited to the above-described embodiments, and may be modified appropriately without departing from the gist of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-120438 | Jun 2014 | JP | national |
