JP2005317354A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of carrying out color display in a background excluding a display part comprising an organic electroluminescent element, in a display device using an organic electroluminescent element. <P>SOLUTION: An organic EL display panel 2 with an organic EL layer 9 arranged between a transparent electrode 7 and an electrode 10 is formed. A reflecting layer 4 is arranged on the invisible side of the organic EL layer 9, and a side light type front light unit 3 having a colored light source is arranged on the visible side of the organic EL layer 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device using an organic electroluminescence element, and more particularly to a display device capable of displaying a background in color with a simple configuration.

  An example of a conventional display device using an organic electroluminescence (hereinafter referred to as organic EL) element is an organic EL display panel, a reflector, and a circularly polarizing plate, and the circularly polarizing plate is the organic display. It is stuck on the viewing side of the EL display panel, and the reflector is stuck on the non-viewing side of the organic EL display panel.

  The organic EL display panel is a laminate in which a transparent electrode made of ITO, an insulating layer, an organic EL layer, and a back electrode made of aluminum are sequentially laminated on the non-viewing side of a transparent substrate, A transparent sealing substrate is disposed on the non-viewing side of the back electrode. The transparent sealing substrate is bonded to the transparent substrate with an ultraviolet curable adhesive. The organic EL layer is composed of a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer.

  The organic EL display panel has three number display units and a unit display unit, and displays the speed of the vehicle. The first number display part is composed of two organic EL elements that display “1”, and the second number display part and the third number display part are seven organic EL elements arranged in a Japanese character form. The unit display unit is composed of “km / h” and four organic EL elements.

  The transparent electrode has a lead part, an anode part connected to one end of the lead part, an anode terminal part connected to the other end of the lead part, and a cathode terminal part, and the first numeric display part Has one anode part, the second number display part and the third number display part each have four anode parts, and the unit display part has one anode part, for a total of ten The anode part is electrically connected to the anode terminal part by the lead part of the transparent electrode. Moreover, each said anode part is a shape which connected each said organic EL element by the connection part. Furthermore, the anode terminal portion and the cathode terminal portion are arranged in a line on one side of the transparent substrate, and a driving voltage is applied to the anode terminal portion and the cathode terminal portion, and the duty ratio is 1/4. It is designed to be driven by time division.

  The insulating layer is provided in almost the entire range of the transparent substrate except for portions corresponding to the organic EL elements.

  The back electrode is composed of a lead portion and a cathode portion, the first number display portion is one cathode portion, the second number display portion and the third number display portion are each two cathode portions. The unit display part has one cathode part, and a total of six cathode parts are electrically connected to the cathode terminal part of the transparent electrode by the lead part of the back electrode.

  The reflection plate is formed by forming a reflection layer made of aluminum on a resin substrate, and is attached to the non-viewing side of the transparent sealing substrate.

  The circularly polarizing plate is composed of a birefringent plate having a birefringent main axis of 45 ° with respect to the longitudinal direction and a linearly polarizing plate having a polarizing axis in the longitudinal direction (that is, having an absorption axis in the lateral direction). And attached to the front surface of the transparent substrate. In the circularly polarizing plate, external light passes through the linearly polarizing plate to become longitudinal linearly polarized light, and further passes through the birefringent plate to become left circularly polarized light. Then, it is reflected to the viewing side by the back electrode and the reflecting plate to become right circularly polarized light, and passes through the birefringent plate to become lateral linearly polarized light. Since the laterally linearly polarized light cannot pass through the linearly polarizing plate having the polarization axis in the longitudinal direction, the external light is incident on the organic EL display panel and reflected by the back electrode and the reflecting plate. Is also blocked by the linearly polarizing plate. On the other hand, the display light is reduced to about half by the linearly polarizing plate, but the display contrast can be increased because the external light is blocked by the linearly polarizing plate (see, for example, Patent Document 1).

JP 2003-257660 A

  However, in the conventional display device described above, it is necessary to dispose a circularly polarizing plate on the viewing side of the organic EL display panel in order to prevent reflection of external light, and thus the light emission luminance of the organic EL element is halved. At the same time, one step of attaching a circularly polarizing plate is required. Further, since the reflected light is shielded by the circularly polarizing plate, the display area (background) other than the light emitting pixels of the organic EL display panel is black.

  Therefore, the present invention provides a display device that does not require a circularly polarizing plate, has a high luminance, and has a simplified manufacturing process, and can easily perform color display in the background of an organic EL display panel. It is for the purpose.

  In order to achieve the above-described object, the display device according to the present invention is characterized by a first electrode, a second electrode facing the first electrode, and the first electrode and the second electrode. A sidelight type comprising: an organic electroluminescence layer disposed on the substrate; a reflective layer disposed on the non-viewing side of the organic electroluminescence layer; and a colored light source disposed on the viewing side of the organic electroluminescence layer And a front light unit. With such a configuration, the reflected light of the background becomes a colored light source color, and a display with excellent cosmetics can be obtained.

  Moreover, it is preferable that the 2nd electrode arrange | positioned on the anti-viewing side among electrodes has the said reflecting layer, and the said front light unit is arrange | positioned on the visual recognition side of the said 1st electrode. By adopting such a configuration, it is not necessary to newly form a reflective layer, and the process is further simplified.

  Furthermore, it is preferable that a plurality of light sources of different colors be disposed on the front light unit. With such a configuration, it is possible to change the light source color over time and enhance the appeal of display.

  Furthermore, it is preferable that the organic electroluminescence layer emits a color different from the color of the light source. By adopting such a configuration, the contrast between the display and the background is increased, and further excellent cosmetics can be obtained.

  According to the display device of the present invention, it is possible to display a display area excluding a light emitting character or image, that is, a background in color.

  In addition, by arranging light sources of a plurality of colors in the front light unit and selectively changing the light sources to light them, the background can be changed to a plurality of colors and displayed.

  Furthermore, by coloring the organic electroluminescence layer, not only the background but also characters or images to be displayed can be displayed in color.

  Hereinafter, embodiments of the display device of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic sectional view showing a first embodiment of a display device according to the present invention.

  As shown in FIG. 1, the display device 1 of the present embodiment includes an organic EL display panel 2 and a front light unit 3, and the front light unit 3 is disposed on the viewing side 2 a of the organic EL display panel 2. It is arranged.

  The organic EL display panel 2 has a pair of transparent substrates 5 and 6 made of glass, plastic, or the like. On the back side of the transparent substrate 5 on the viewing side, a transparent electrode 7 made of ITO, an insulating layer 8, and organic An EL layer 9 and a light reflective electrode 10 made of aluminum are sequentially formed. In the present embodiment, the transparent electrode 7 is an anode electrode, and the electrode 10 is a cathode electrode.

  For example, the organic EL layer 9 is configured by laminating a hole transport layer 11, a light emitting layer 12, and an electron transport layer 13, and the light emitting layer 12 includes a white organic EL element (also referred to as OLED). A display portion 12a formed on characters or images is formed. Although only one display pixel is shown in FIG. 1 for simplification of explanation, the organic EL display panel 2 of the first embodiment has a plurality of strip-like transparent electrodes 7 arranged therein. A plurality of strip-like electrodes 10 are arranged so as to be orthogonal to the transparent electrode 7, and a dot matrix display form is formed in which a plurality of display pixels form a matrix.

  Then, the transparent substrates 5 and 6 are opposed to each other, a sealing material 14 is disposed on the peripheral edge of the transparent substrates 5 and 6, and the transparent substrates 5 and 6 are bonded to each other, thereby the organic EL display panel 2. Is formed. At this time, a gap is provided between the transparent substrates 5 and 6 by the sealing material 14, and a desiccant for preventing light emission failure due to moisture is provided in the gap. In addition, since the said sealing material 14 has the characteristic that an organic EL element will deteriorate quality with a heat | fever, it is preferable to use an ultraviolet curable resin.

  The front light unit 3 is a side light type, and a light guide plate 15 made of, for example, polycarbonate resin is provided so as to cover the entire display area of the organic EL display panel 2, and a side of the light guide plate 15. The light emitted from the light source 16 is incident on the organic EL display panel 2 through the light guide plate 15. In the present embodiment, a red light emitting diode (LED) or a fluorescent tube is used for the light source 16.

  According to the display device 1 of the present embodiment configured as described above, the light source 16 of the front light unit 3 emits light, and the display unit 12a in the dot matrix type display area of the organic EL display panel 2 emits light. The display unit 12a is displayed in white, and red light emitted from the light source 16 of the front light unit 3 is reflected by the reflective layer, that is, the electrode 10 disposed on the non-viewing side of the organic EL layer 9, so The display area excluding the background, that is, the background can be illuminated in red. At this time, the background color is the light from the front light unit 3 reflected by the reflecting plate 4, and the display unit 12a emits light spontaneously. Display can be performed.

  A second embodiment of the display device according to the present invention will be described with reference to FIG.

  FIG. 2 is a schematic cross-sectional view of a display device 1 having a segment type display form. Elements that are the same as or similar to those in FIG. 1 are given the same reference numerals.

  As in the first embodiment, the organic EL display panel 2 includes a transparent electrode 7 having a predetermined shape on the back surface of the transparent substrate 5 on the viewing side, an insulating film 8 having a pixel opening, and an organic material that emits yellow light. An EL layer 9 and an electrode 10 made of aluminum having a predetermined shape are sequentially formed. A segment-type display portion 12a is formed by the facing portion of the transparent electrode 7 having a predetermined shape and the electrode 10 having a predetermined shape. In the present embodiment, the electrode 10 may be a transparent electrode.

  And the organic EL display panel 2 is formed by making the transparent substrate 5 and the transparent substrate 6 which is a sealing substrate face each other and fix them as in the first embodiment. On the non-viewing side of the organic EL display panel 2, a reflection plate 20 having a reflection layer 18 made of aluminum or the like is disposed on the resin substrate 17 so as to cover the position where the sealing material 14 is disposed. Further, a front light unit 3 similar to that of the first embodiment is disposed on the viewing side 2 a of the organic EL display panel 2.

  According to the display device 1 of the second embodiment having such a configuration, the display section 12a that emits light is displayed in yellow, and other portions corresponding to the background are reflected by the reflection layer 18 by the front light unit. It becomes red from 3. Moreover, it is preferable from a viewpoint of the visibility of a display that the luminance from the organic EL layer 9 is higher than the luminance from the front light unit 3.

  In another embodiment, the front light unit 3 is provided with, for example, red and blue light sources 16, respectively, and selectively emits red or blue light, thereby selectively changing the background color to red or blue. be able to.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed. In the present embodiment, the front light unit is configured differently from the organic EL display panel. However, if the transparent substrate on the viewing side of the organic EL display panel can have the function of the light guide plate of the front light, the light guide plate is organic EL. A substrate for a display panel may be used. Further, the organic EL display panel in the present embodiment is bottom emission in which light is extracted from the anode side through the substrate, but may be top emission in which light is extracted from the cathode side.

Schematic sectional view showing an embodiment of a display device according to the present invention Schematic sectional view showing another embodiment of the display device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Organic electroluminescent display panel 3 Front light unit 4 Reflective layer 5,6 Transparent substrate 7 Transparent electrode 8 Insulating layer 9 Organic EL layer 10 Electrode 11 Hole transport layer 12 Light emitting layer 13 Electron transport layer 14 Sealing material 15 Conduction Optical plate 16 Light source 17 Resin substrate 18 Reflective layer 20 Reflector

Claims (4)

A first electrode;
A second electrode facing the first electrode;
An organic electroluminescence layer disposed between the first electrode and the second electrode;
A reflective layer disposed on the non-viewing side of the organic electroluminescence layer;
A sidelight type front light unit having a colored light source disposed on the viewing side of the organic electroluminescence layer;
A display device.   2. The display device according to claim 1, wherein a second electrode disposed on a non-viewing side of the electrode includes the reflective layer, and the front light unit is disposed on a viewing side of the first electrode. .   The display device according to claim 1, wherein a plurality of light sources of different colors are arranged on the front light unit.   The display device according to claim 1, wherein the organic electroluminescence layer emits a color different from a color of the light source.