JP2010008476A - Organic el display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL (Electroluminescence) display device which has improved indoor visibility and improved outdoor visibility of a display screen. <P>SOLUTION: The organic EL display device includes: a housing having an opening formed therein; an organic EL panel disposed in the housing and having a display area which is visible from the opening; a protective plate fitted to the housing to be movable between a first position on the display area and a second position off on the display area and having a light reflection preventing function; a detecting part which detects whether the protective plate is at the first position, an optical sensor which measures the quantity of external light of the housing, and a luminance adjustment part which adjusts light emission luminance of the organic EL panel based upon the outputs of the detecting part and optical sensor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL display device used for a notebook computer, a mobile phone, and the like.

  At present, researches on organic EL (Electroluminescence) display devices are underway as flat panel displays that replace the mainstream liquid crystal displays. Compared with a liquid crystal display device, the organic EL display device has the advantages of a wide viewing angle, a high response speed, high brightness, and high contrast. In addition, since a backlight is not necessary, it can be thinned and is expected as a next-generation display device.

  Such an organic EL display device is provided with a protective plate on the surface in order to protect the display screen. Therefore, a boundary surface with the air layer is formed between the protective plate and the EL display device, and when external light is incident from the protective plate, the incident light is reflected between each boundary surface and visibility is lowered. There is a problem of doing. When the external light is strong, the display screen cannot be visually recognized.

In view of this, a technique for visually recognizing the surface by designing the incident light to interfere with each other reflected light generated at the interface between the thin films and providing an antireflection layer having an antireflection effect on the protective plate is disclosed. In addition, an antireflection layer is provided on the outer surface of the display surface of the display panel, and retardation plates are installed on the upper and lower surfaces to reduce surface reflection at each boundary surface, even under strong external light. A technique for obtaining high-quality visibility is disclosed (for example, see Patent Document 1 or Patent Document 2).
JP 10-301099 A JP-A-2001-311949

  However, when the above technique is used, the visibility of the display screen is improved by suppressing the reflection of outside light under strong outdoor light, but the display screen becomes dark due to the antireflection layer, the polarizing plate, etc. There was a problem that visibility in an environment where the surroundings were bright was reduced. The problem becomes more prominent as the number of antireflection layers or polarizing plates increases.

  In view of the above problems, the present invention provides an organic EL display device that can suppress reflection of external light and can improve visibility even in a relatively bright environment.

  An organic EL display device according to the present invention includes a housing in which an opening is formed, an organic EL panel that is disposed in the housing and includes a display area that is visible from the opening, and a first position on the display area. And a second position deviating from the display area, a protective plate having a light reflection preventing function attached to the housing in a movable state, and whether or not the protective plate is located at the first position. A detection unit for detecting, an optical sensor for measuring the external light amount of the housing, and a luminance adjustment unit for adjusting the light emission luminance of the organic EL panel based on the output of the detection unit and the optical sensor. It is characterized by.

  In the above invention, it is preferable that the optical sensor measures an external light amount at a peripheral edge portion of the opening.

  In the above invention, the first position is preferably on an opening of the housing.

  In the above invention, the first position is preferably between the display area of the organic EL panel and the opening of the housing.

  In the above invention, the protective plate having the antireflection function preferably includes a transparent substrate and an antireflection layer, a retardation plate and a polarizing plate formed on the transparent substrate.

  In the above invention, when the protective plate is disposed in the first position, it is preferable that the retardation plate, the polarizing plate, and the antireflection layer are sequentially formed upward from the transparent substrate. .

  In the above invention, when the protective plate is disposed at the first position, the antireflection layer is formed above the transparent substrate, and the polarizing plate and the retardation plate are formed of the transparent substrate. It is preferable that they are sequentially formed downward from the bottom.

  According to the organic EL display device of the present invention, the light emission luminance of the organic EL panel can be automatically adjusted by the output of the optical sensor and the output of the detection unit. Therefore, it is possible to improve both visibility under strong outdoor light and visibility in a bright environment.

Example 1
An organic EL display device according to Example 1 of the present invention will be specifically described with reference to FIGS. FIG. 1 is a perspective view of a mobile phone terminal 1 which is an example of the organic EL display device according to the first embodiment. FIG. 2 is a block diagram illustrating functions of the organic EL display device according to the first embodiment. 3 and 4 are perspective views showing a state in which the protective plate is moved from the first position to the second position in the organic EL display device according to the present invention.

  The cellular phone terminal 1 includes a housing 2, an organic EL panel 3 disposed inside the housing 2, and a protection plate 5 that protects the organic EL panel 3 and has a light reflection preventing function. . The housing 2 has a substantially rectangular outer shape, and a predetermined opening 20 is formed on the upper surface. The display area of the organic EL panel 3 emits light from the inside of the housing 2 toward the opening 20 formed on the upper surface, and the display area can be visually recognized from the opening 20. Of the side surfaces of the housing 2, two long side surfaces (long side surfaces) are formed with groove portions 21 extending to the short side surfaces (short side surfaces). The cellular phone terminal 1 includes an operation button, a speaker, a receiver, a camera, and the like, which are arranged in a space other than the opening 20 on the upper surface of the housing 2, but are not shown in the drawing. .

  The protection plate 5 is formed with a reflection preventing layer or the like having a light reflection preventing function, and a groove portion 21 formed on the long side surface of the housing 2 while sandwiching the body portion 55. An insertion portion 56 is provided. The protective plate 5 is disposed in a position (first position) on the display area, that is, in a direction for extracting light from the display area of the organic EL panel 3.

  FIG. 2 is a block diagram illustrating functions of the organic EL display device according to the first example. The cellular phone terminal 1 includes an organic EL panel 3, an optical sensor 4, a detection unit 6, a luminance adjustment unit 7, a control unit 10, an X driver Xd, and a Y driver Yd.

  As the organic EL panel 3, for example, a panel in which a plurality of pixels having organic EL elements are arranged in a matrix can be used. Here, the organic EL element is a self-luminous element that has a light-emitting layer made of an organic material and the like, and whose luminance is changed by a current flowing through the light-emitting layer.

  The optical sensor 4 measures the amount of light (or light intensity) outside the housing 2. In addition, the optical sensor 4 outputs the measured value of the external light amount to the luminance adjustment unit 7 described later. For example, the output value A is output to the luminance adjustment unit 6 when the external light amount is equal to or greater than the predetermined value, and the output value B is output when the external light amount is equal to or less than the predetermined value.

  The detection unit 6 detects whether or not the protective plate 5 is located at the first position. In addition, the optical sensor 4 outputs the detection result to the luminance adjustment unit 7 described later. For example, when the protective plate 5 is located at the first position, the output value α is output to the luminance adjusting unit 6, and when the protection plate 5 is not located at the first position, the output value β is output.

  The luminance adjustment unit 7 has a function of adjusting the light emission luminance of the organic EL panel 3 based on the output of the optical sensor 4 and the output of the detection unit 6. For example, when the output value A when the external light quantity is greater than or equal to the predetermined value and the protective plate 5 is positioned at the first position, the amount of current flowing through the organic EL element is increased when the output value α is input. By controlling, the light emission luminance of the organic EL panel is improved. Further, when the output value B when the external light amount is equal to or less than the predetermined value or the output value β when the protective plate 5 is not positioned at the first position is input, control is performed so as to maintain the amount of current flowing through the organic EL element. By doing so, an increase in power consumption is suppressed.

  The control unit 10 performs overall control of the operation of the organic EL display device 1. The control unit 10 includes a CPU, a RAM, a ROM, and the like. For example, the CPU reads and executes a program stored in the ROM or the like, thereby realizing various operations and controls. The control unit 10 also has a function of controlling transmission of signals from an X driver Xd and a Y driver Yd described later.

  The X driver Xd has a function of supplying a potential corresponding to an image signal to each pixel via a signal line in response to a signal from the control unit 10. The Y driver Yd has a waveform corresponding to a control signal from the control unit 10 and has a function of supplying a potential corresponding to the scanning signal to each pixel via the scanning line.

  Next, in the cellular phone terminal 1 of FIGS. 3 and 4, a perspective view of a process of moving the protective plate from the first position to the second position is shown. In the mobile phone terminal 1 according to the first embodiment, as shown in FIG. 3, the protective plate 5 is once removed from the groove portion 21 of the housing 2 and inverted, and then the main body portion 55 of the protective plate 5 is formed as shown in FIG. 4. The protective plate 5 is inserted into the groove portion 21 of the housing 2 so that the position deviates from the display area of the organic EL panel 3, that is, the main body portion 55 of the protective plate 5 is located on the lower surface side of the housing 2 (second position). Part 56 can be inserted.

  As a result, when the mobile phone terminal 1 is used outdoors where the outside light is strong and the visibility of the display area is low due to the reflection of the outside light, the first protection plate 5 on which the antireflection layer is formed is used. By placing it in a position, it is possible to suppress a decrease in visibility due to the reflection of external light, and when the display screen is felt dark by the protective plate 5 in an environment where the external light reflection is relatively small but the surroundings are bright Can suppress the deterioration of the visibility of the display area of the organic EL panel 3 by disposing the protective plate 5 in the second position.

  Moreover, in the structure which makes the 1st position on the opening 20 of the housing | casing 2 like the said Example 1, since the operativity in moving a 1st position and a 2nd position manually is high, it is preferable.

  As a modification of the first embodiment, there is a configuration in which the protective plate 5 is disposed between the display area of the organic EL panel 3 and the opening 20 of the housing 2. If the first position is between the display area and the opening 20 of the housing 2, a groove 21 is formed inside the housing 2, and the protective plate 5 is slid inside the housing 2, so that the first position and the first position Two positions can be moved. This configuration is preferable because it is less likely to come into contact with other objects when moving between the first position and the second position, and the safety is high.

  In the first embodiment, the protective plate 5 is disposed only corresponding to the opening 20 of the housing 2, but covers other portions on the upper surface of the housing 2 to correspond to operation buttons and speakers. An opening may be provided at the position. Further, the protective plate 5 may be attached to the housing 2 so that the first position and the second position can be moved together with a part of the housing 2.

(Example 2)
An organic EL display device according to Example 2 of the present invention will be specifically described with reference to the drawings. 5 and 6 are perspective views of the cellular phone terminal 1 that is the organic EL display device according to the second embodiment. Similar to the first embodiment, the cellular phone terminal 1 includes a housing 2, an organic EL panel 3 disposed inside the housing 2, and a protective plate 5 for protecting the organic EL panel 3. . The casing 2 has a substantially rectangular outer shape, and a predetermined opening 20 is formed on the upper surface of the casing 2.

  Of the side surfaces of the housing 2, a rotating shaft portion 22 is formed on two side surfaces (long side surfaces) on the long side. Further, the protection plate 5 includes a main body portion 55 on which an antireflection layer is formed, and an insertion portion 56 that is formed with the main body portion 55 interposed therebetween and inserted into the rotary shaft portion 22 of the housing 2. In FIG. 4, the protective plate 5 is disposed in a position (first position) covering the opening 20 of the housing 2, that is, in a direction of extracting light from the display area of the organic EL panel 3.

  In the mobile phone terminal 1 according to the second embodiment, as shown in FIG. 6, the protective plate 5 is rotated upward with respect to the rotation shaft portion 22 of the housing 2, so that the display area of the organic EL panel 3 is removed. It is possible to move to a position that deviates, that is, a position that deviates from the light extraction direction of the display area (second position).

  Accordingly, as in the first embodiment, when the mobile phone terminal 1 is used in a field where strong external light is strong, and when it is felt that the visibility of the display area of the organic EL panel is low due to reflection of external light, antireflection is performed. By disposing the protective plate 5 on which the layer is formed at the first position, it is possible to suppress a decrease in visibility due to reflection of external light, and to protect in an environment where the ambient light is relatively light but the surroundings are bright. When it is felt that the display screen is dark due to the board, it is possible to suppress a decrease in visibility by arranging the protective plate 5 at the second position.

  Further, in the present embodiment, similarly to the first embodiment, other portions on the upper surface of the housing 2 may be covered, and an opening may be provided at a position corresponding to the operation button or the speaker.

  In the first embodiment and the second embodiment, the deterioration of the visibility of the display area due to the reflection of outside light in the outdoors can be reduced by the protective plate having the antireflection function, and the protective plate having the antireflection function is attached. The decrease in visibility due to this can be automatically adjusted appropriately by the luminance adjustment unit based on the outputs of the optical sensor and the detection unit. By providing these functions, it is possible to improve both visibility of the display screen under strong outdoor light and visibility in a bright environment, and it is possible to reduce power consumption.

(About protective plate)
The protective plate 5 used in the first and second embodiments will be described in detail below with reference to the drawings. As the protective plate 5, glass, plastic resin, or the like can be used as the material of the transparent substrate 50. Moreover, for example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, diacetyl cellulose, triacetyl cellulose polymers, polycarbonate polymers, acrylic polymers such as polymethyl methacrylate, and the like can be used. Also, styrene polymers such as polystyrene, acrylonitrile / styrene copolymer, olefin polymers such as polyethylene, polypropylene, polyolefin, ethylene / propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, etc. A transparent polymer or the like can also be used. Furthermore, imide polymers, sulfone polymers, polyether sulfone polymers, polyether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers polyoxymethylene polymers In addition to the arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, etc., the above-mentioned polymer blends can be used. In particular, those having low optical birefringence are preferred. When glass is used, tempered glass is desirable from the viewpoint of strength.

  The thickness of the transparent substrate 50 can be determined as appropriate, but a base of about 100 to 1500 μm is used from the viewpoint of strength, workability, and the like.

  Further, an antireflection layer 51 is formed at least on the upper surface side of the transparent substrate 50 (the outer side in the first position). The antireflection layer 51 is also referred to as an AR (Anti-Reflection) layer, and reduces the reflection of light by coherently adding the amplitude of reflected light at the layer boundary surface.

  The antireflection layer 51 includes, for example, an AR (anti-reflection) layer and a hard coat layer formed of a thermosetting resin, a thermoplastic resin, an ultraviolet curable resin, an electron beam curable resin, a two-component mixed resin, or the like. And what consists of a PET film and an adhesion layer can be used.

  In the case of adopting the above structure, among the above-described resins, an ultraviolet curable resin is preferable because a light diffusion layer can be efficiently formed by a simple processing operation. Examples of the ultraviolet curable resin include polyester-based, acrylic-based, urethane-based, amide-based, silicone-based, and epoxy-based resins.

  The adhesive layer is made of, for example, natural or synthetic resins, in particular, tackifier resins, fillers or pigments made of glass fibers, glass beads, metal powders, other inorganic powders, coloring agents, and antioxidants. An additive such as an agent may be contained.

  Moreover, it is preferable that a hard-coat layer is about 1-5 micrometers thick, and forms the adhesion layer in about 10-20 micrometers. By setting the thickness of the hard coat layer to 5 μm or more, the hardness of the protective film is increased, and further, by setting the thickness of the adhesive layer to 20 μm or less, sinking of the protective film against the external load can be suppressed, As a result, the scratch resistance of the protective film surface is improved.

  The antireflection layer 51 preferably has a reflectance of 1.5% or less. Further, an antiglare layer may be formed in which fine irregularities are formed on the surface of the antireflection layer 51, and external light is diffused in multiple directions to prevent external light reflection from directly entering the eye.

  In addition to the antireflection layer 51, the protective plate 5 may have a polarizing plate 52 attached to the outer surface side and / or the inner surface side of the transparent substrate 50.

  In addition to the polarizing plate 52, a retardation plate 53 may be further laminated. The phase difference plate 53 is used when changing linearly polarized light into elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light into linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called 1 / 4λ phase difference plate is used as the phase difference plate 53 that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light.

  FIG. 7 shows the configuration of the protective plate 5 disposed on the organic EL panel 3 in the first and second embodiments. The protective plate 5 has a polarizing plate 52 and a phase difference plate 53 (1 / 4λ phase difference plate) sequentially formed on the lower surface side (organic EL panel 3 side) of the transparent substrate 50, and the upper surface side (transparent plate 50). An antireflection layer 51 is formed on the outer side. Here, the transparent substrate 50 is made of tempered glass, and the antireflection layer 51 is made of a PET film with an AR (anti-reflection) layer and an HC (hard coat) layer laminated on its surface, and an adhesive on the back surface. A layer is formed. In this configuration, there is no polarizing plate and retardation plate directly under the antireflection layer, and it is formed directly on the tempered glass substrate. This is preferable in terms of improving scratch resistance.

  As other configurations of the protective plate 5, as shown in FIG. 8, a retardation plate 53 (¼λ retardation plate), a polarizing plate 52, and an antireflection layer are formed on the transparent substrate 50 from the organic EL panel 3 side. 51 may be formed sequentially. In this configuration, since the antireflection layer, the polarizing plate and the retardation plate are laminated, by preparing a film in which the antireflection layer, the polarizing plate and the retardation plate are laminated in advance, A predetermined protective plate can be formed simply by sticking to a transparent substrate made of a tempered glass substrate, which is preferable in terms of improving workability.

In the organic EL display device of Example 1, it is a perspective view when a protective plate is disposed at a first position. FIG. 1 is a block diagram illustrating functions of an organic EL display device according to Example 1. FIG. In the organic EL display device of Example 1, it is a perspective view showing a step of moving the protective plate from the first position to the second position. In the organic EL display device of Example 1, it is a perspective view when a protective plate is disposed at a second position. In the organic EL display device of Example 2, it is a perspective view when a protective plate is disposed at a first position. In the organic EL display device of Example 2, it is a perspective view showing a step of moving the protective plate from the first position to the second position. It is the schematic which shows the structure of the protective plate used for the Example. It is the schematic which shows the other structure of a protective layer.

Explanation of symbols

1 Organic EL display device (mobile phone terminal)
2 Housing 20 Opening 21 Groove 22 Rotating shaft 3 Organic EL panel 4 Optical sensor 5 Protection plate 50 Transparent substrate 51 Antireflection layer 52 Polarizing plate 53 Phase difference plate (1 / 4λ phase plate)
55 Main Body 56 Insertion Unit 6 Detection Unit 7 Brightness Adjustment Unit

Claims (7)

A housing in which an opening is formed;
An organic EL panel provided with a display region disposed in the housing and visible from the opening;
A protective plate having an antireflection function for light attached to the housing in a movable state between a first position on the display area and a second position off the display area;
A detection unit for detecting whether or not the protective plate is located at the first position;
An optical sensor for measuring the external light quantity of the housing;
A luminance adjusting unit that adjusts the luminance of the organic EL panel based on the outputs of the detection unit and the optical sensor;
An organic EL display device comprising:   The organic EL display device according to claim 1, wherein the optical sensor measures an external light amount at a peripheral portion of the opening.   The organic EL display device according to claim 1, wherein the first position is on an opening of the housing.   The organic EL display device according to claim 1, wherein the first position is between a display region of the organic EL panel and an opening of the housing.   The protective plate having an antireflection function includes a transparent substrate, and an antireflection layer, a retardation plate, and a polarizing plate formed on the transparent substrate. The organic EL display device described.   The retardation plate, the polarizing plate, and the antireflection layer are sequentially formed upward from the transparent substrate when the protective plate is disposed in the first position. 5. The organic EL display device according to any one of 5 above. In the case where the protective plate is disposed at the first position, the antireflection layer is formed above the transparent substrate,
The organic EL display device according to claim 1, wherein the polarizing plate and the retardation plate are sequentially formed downward from the transparent substrate.

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