JP2005283940A - Driving method for organic electroluminescence panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving method for an organic electroluminescence (OEL) panel capable of enhancing merchantability of the OEL panel by performing novel display. <P>SOLUTION: In the driving method for the OEL panel 4, an OEL element 11 in which an OEL layer 11c including at least a light emitting layer between a pair of electrodes (a first and a second electrode) 11a and 11b, is arranged on a substrate 10. When the OEL element 11 is light emitted, the OEL element 11 is controlled to reach a predetermined brightness level gradually from a non-light emitted state. Moreover, when the OEL element 11 is turned to be in the non-light emitted state from a light emitted state, the OEL element 11 is controlled to reach the non-light emitted state gradually from the predetermined brightness level. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for driving an organic EL panel in which an organic EL (electroluminescence) element is disposed on a translucent substrate.

  Conventionally, on a translucent substrate, made of a translucent conductive material such as ITO (Indium Tin Oxide), a first electrode serving as an anode, an organic layer having at least a light emitting layer, aluminum (Al) or magnesium An organic EL panel made of a conductive material having a lower resistivity than the first electrode, such as silver (Mg: Ag), and having an organic EL element sequentially formed with a second electrode serving as a cathode is known. (For example, refer to Patent Document 1).

In such an organic EL panel, a direct current power source is connected between the first electrode and the second electrode, and a current is supplied between the two electrodes, whereby the organic layer emits light, and the emitted light is emitted from the substrate. The laminated portion of the first electrode, the organic layer, and the second electrode serves as a light emitting portion.
Japanese Patent Laid-Open No. 5-234681

  However, when the organic EL panel is applied to a display device such as a vehicle instrument, it has been desired to devise a display method using the light emitting unit to improve the commercial property of the organic EL panel.

  An object of the present invention is to provide a driving method of an organic EL panel capable of improving the merchantability of an organic EL panel by focusing on such problems and performing novel display.

  In order to solve the above-described problems, the present invention provides a method for driving an organic EL panel in which an organic EL element in which an organic layer having at least a light emitting layer is formed between a pair of electrodes is disposed on a substrate. When the organic EL element is caused to emit light, the organic EL element is controlled to gradually reach a predetermined luminance from a non-light emitting state.

  Further, the current value applied to the organic EL element is increased continuously or stepwise.

  The time for applying a current to the organic EL element may be increased continuously or stepwise.

  The time until the organic EL element reaches the predetermined luminance can be arbitrarily changed.

  In order to solve the above-described problems, the present invention provides a method for driving an organic EL panel in which an organic EL element in which an organic layer having at least a light emitting layer is formed between a pair of electrodes is disposed on a substrate. When the organic EL element is changed from a light emitting state to a non-light emitting state, the organic EL element is controlled so as to gradually reach a non-light emitting state from a predetermined luminance.

  The current value applied to the organic EL element is reduced continuously or stepwise.

  In addition, the time for applying a current to the organic EL element is reduced continuously or stepwise.

  In addition, the time until the organic EL element reaches a non-light emitting state can be arbitrarily changed.

  The present invention relates to a method for driving an organic EL panel in which an organic EL element is disposed on a light-transmitting substrate, and makes it possible to perform novel display and improve the merchantability of the organic EL panel.

  Hereinafter, an embodiment in which the present invention is applied to a display device that displays the engine speed of a vehicle will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an electrical configuration of the display device 1. The display device 1 mainly includes an input unit 2, a control unit 3, and an organic EL panel 4.

  The input unit 2 includes a signal line for inputting a pulse signal (TA pulse) from the ignition coil, and outputs a state signal corresponding to the engine speed of the vehicle to the control unit 3.

  The control means 3 is composed of a microcomputer that operates based on a predetermined program. The control means 3 inputs the state signal corresponding to the engine speed from the input means 2 and performs an output process for displaying the organic EL panel 4. An input / output port (input / output circuit), a ROM in which a processing program for controlling the display mode in the organic EL panel 4 is stored, a CPU that executes predetermined arithmetic processing and performs predetermined processing, and for arithmetic processing RAM is temporarily stored, and the organic EL panel 4 is driven and controlled based on the state signal from the input means 2. The control means 3 inputs the state signal to the input port, calculates a measured value indicating the engine speed by performing a predetermined calculation process, and outputs a processing signal corresponding to the calculated measured value. Output from the port to the organic EL panel 4 via the drive circuit 4a.

  The organic EL panel 4 is driven and controlled by inputting a drive signal output from the control means 3 via the drive circuit 4a, and displays a display image indicating the engine speed. As shown in FIG. 2, the organic EL panel 4 has a bar display that displays a scale display unit 4b that displays a scale of the engine speed and a plurality of bars 4c1 that show the engine speed along the scale as a light emitting unit. The unit 4c and a unit display unit 4d indicating the unit of engine speed (× 1000 RPM) are provided, and the display image is formed by the display light of each of the display units 4b to 4d.

  In addition, as shown in FIG. 3, the organic EL panel 4 includes an organic EL element 11 disposed on a substrate 10 made of a translucent glass material. A sealing member 12 is disposed on the substrate 10 so as to airtightly cover the organic EL element 11.

  The organic EL element 11 is formed by sequentially laminating a first electrode 11a, an insulating layer 11b, an organic layer 11c, and a second electrode 11d. The first electrode 11a, the organic layer 11c, and the second electrode Each display part 4b-4d is comprised by the laminated part of 11c.

  The first electrode 11a is connected to an external power source (not shown) and serves as an anode for injecting holes into the organic layer 11c. A conductive material such as ITO is deposited on the substrate 10 by means such as vapor deposition or sputtering. Is formed into a layer having a thickness of 50 to 200 nm, and is patterned according to the display design of each of the display portions 4b to 4d by a photolithography method or the like.

  The insulating layer 11b is made of an insulating material such as polyimide or phenol, and is formed in a predetermined shape on a non-light emitting portion on the support substrate 2 by means such as photolithography. The insulating layer 11b is formed so as to slightly overlap the peripheral edge of the display segment 3a of the first electrode 11a in order to clearly display the outline of the light emitting region, and also insulates the first electrode 11a and the second electrode 11d. Formed to ensure.

  The organic layer 11c is formed with a predetermined size on the first electrode 11a and the insulating layer 11b so as to correspond to the portion where the first electrode 11a is exposed. In the present embodiment, the hole transport layer is formed. The light emitting layer, the electron transporting layer, and the electron injecting layer are sequentially laminated by means such as vapor deposition. The organic layer 11c only needs to have at least a light emitting layer.

  The second electrode 11d is connected to the external power source and serves as a cathode for injecting electrons into the organic layer 11c. A conductive material such as aluminum (Al) or magnesium silver (Mg: Ag) is used as a vapor deposition method or the like. Is formed in a layered form with a film thickness of 50 to 200 nm on the organic layer 11c.

  The sealing member 12 is formed by forming a recess 12a in a flat plate member made of, for example, a glass material by an appropriate method such as sandblasting, cutting, and etching. The sealing member 12 is airtightly disposed on the substrate 10 with a support portion 12b formed so as to surround the recess 12a on an adhesive 12c made of, for example, an ultraviolet curable epoxy resin. The organic EL element 10 is sealed with the substrate 10.

  Next, a method for driving the organic EL panel 4 will be described with reference to FIGS.

  FIG. 4 is a diagram showing the relationship between the light emission time and the light emission luminance when each bar 4c1 in the bar display portion 4c of the organic EL panel 4 emits light.

  When the control unit 3 causes the bar 4c1 to emit light based on the state signal from the input unit 2, the current value applied to the organic EL panel 4 to cause the bar 4c1 to emit light is continuously increased to a predetermined value during time t1. The drive circuit 4a is controlled so as to increase. Therefore, as shown in FIG. 4, the bar 4c1 emits light so as to gradually reach the light emission luminance L1 from the non-light emitting state during the time t1. The time t1 is set to such an extent that the user can recognize the change in the light emission luminance. Further, the control means 3 can arbitrarily change the time t1 in accordance with, for example, an operation signal from an operation switch (not shown). In addition, when the control unit 3 causes the bar 4c1 to emit light based on the state signal from the input unit 2, the current value applied to the organic EL panel 4 to emit the bar 4c1 from the drive circuit 4a during the time t1. The processing signal may be output so as to increase stepwise up to a predetermined value.

  FIG. 5 is a diagram showing the relationship between the light emission time and the light emission luminance when each bar 4c1 in the bar display portion 4c of the organic EL panel 4 is switched from the light emitting state to the non-light emitting state.

  When the control unit 3 sets the bar 4c1 to the non-light emitting state based on the state signal from the input unit 2, the control unit 3 sets the current value applied to the organic EL panel 4 to emit the bar 4c1 during the time t2. The drive circuit 4a is controlled so as to continuously decrease from 1 to a value (for example, 0 A) at which the bar 4c1 is in a non-light emitting state. Therefore, as shown in FIG. 5, the bar 4c1 gradually reaches the non-light emission state from the light emission luminance L1 during the time t2. Note that the time t2 is set to such an extent that the user can recognize the change in the light emission luminance, similarly to the time t1. Further, the control means 3 can arbitrarily change the time t2 by the operation switch. In addition, when the control unit 3 sets the bar 4c1 to the non-light emitting state based on the state signal from the input unit 2, the current value applied to the organic EL panel 4 in order to cause the bar 4c1 to emit light from the drive circuit 4a is timed. The processing signal may be output so as to decrease stepwise from the predetermined value to a value (for example, 0 A) at which the bar 4c1 is in a non-light emitting state during t2.

  In the driving method of the organic EL panel 4, when the bar 4c1 of the bar display unit 4c configured by the organic EL element 11 emits light, the bar 4c1 is controlled so as to gradually reach a predetermined luminance L1 from the non-light emitting state. Is. Further, the current value applied to the organic EL panel 4 for causing the bar 4c1 to emit light is increased continuously or stepwise.

  Further, the driving method of the organic EL panel 4 is such that when the bar 4c1 of the bar display unit 4c configured by the organic EL element 11 is changed from the light emitting state to the non-light emitting state, the bar 4c1 is gradually turned off from the predetermined luminance L1. Control is performed so that the light emission state is reached. In addition, the current value applied to the organic EL panel 4 for causing the bar 4c1 to emit light is decreased continuously or stepwise.

  Accordingly, when the engine speed of the vehicle is displayed by switching the display / non-display of the plurality of bars 4c1 of the bar display unit 4c, the bar 4c1 is gradually displayed or gradually hidden so that light emission is simply performed. Compared with a conventional organic EL panel that switches between a state and a non-light-emitting state, it is possible to perform a novel display that allows the user to feel more smoothly switching between display and non-display, and to improve the commerciality of the organic EL panel Is possible.

  In addition, the time t1 until the bar 4c1 reaches the predetermined luminance L1 and the time t2 until the bar 4c1 reaches the non-light emitting state can be arbitrarily changed, thereby setting the time during which the light emission luminance changes according to the user's preference. Therefore, it is possible to improve the merchantability as an organic EL panel.

  In the present embodiment, the driving method of the organic EL panel 4 increases the current value applied to the organic EL panel 4 continuously or stepwise in order to gradually set the bar 4c1 to the predetermined luminance L1. In addition, the current applied to the organic EL panel 4 is decreased continuously or stepwise in order to gradually turn the bar 4c1 into the non-light emitting state, but the light emitting portion in the organic EL element is caused to emit light. In this case, the organic EL element can also be changed by changing the duty ratio of the current applied to the organic EL element continuously or stepwise to increase the time for applying the current to the organic EL element continuously or stepwise. The element can be controlled to gradually reach a predetermined luminance. Further, when the organic EL element is changed from the light emitting state to the non-light emitting state, the duty ratio of the current applied to the organic EL element is changed continuously or stepwise, and a time for applying the current to the organic EL element is set. The organic EL element can also be controlled so as to gradually reach a non-light emitting state from a predetermined luminance by a method of decreasing continuously or stepwise.

  Further, the organic EL panel driving method of the present invention is applicable to any organic EL panel including either a segment type organic EL element or a dot matrix type organic EL element.

1 is a block diagram illustrating a display device according to an embodiment of the present invention. The top view explaining an organic electroluminescent panel same as the above. The principal part sectional view explaining an organic EL panel same as the above. The figure explaining the drive method of an organic electroluminescent panel same as the above. The figure explaining the drive method of an organic electroluminescent panel same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Input means 3 Control means 4 Organic EL panel 4a Circuit board 4b Scale display part 4c Bar display part 4c1 Bar 4d Unit display part 10 Substrate 11 Organic EL element 11a First electrode 11b Insulating layer 11c Organic layer 11d Second electrode 12 Sealing member

Claims (8)

A method for driving an organic EL panel in which an organic EL element in which an organic layer having at least a light emitting layer is formed between a pair of electrodes is disposed on a substrate,
A method for driving an organic EL panel, wherein when the organic EL element is caused to emit light, the organic EL element is controlled so as to gradually reach a predetermined luminance from a non-light emitting state. 2. The method of driving an organic EL panel according to claim 1, wherein a current value applied to the organic EL element is increased continuously or stepwise. 2. The method of driving an organic EL panel according to claim 1, wherein a time for applying a current to the organic EL element is increased continuously or stepwise. 2. The method of driving an organic EL panel according to claim 1, wherein the time until the organic EL element reaches the predetermined luminance can be arbitrarily changed. A method for driving an organic EL panel in which an organic EL element in which an organic layer having at least a light emitting layer is formed between a pair of electrodes is disposed on a substrate,
A method for driving an organic EL panel, comprising: controlling the organic EL element from a predetermined luminance to a non-light-emitting state gradually when the organic EL element is changed from a light-emitting state to a non-light-emitting state. 6. The method of driving an organic EL panel according to claim 5, wherein the current value applied to the organic EL element is decreased continuously or stepwise. 6. The method of driving an organic EL panel according to claim 5, wherein a time for applying a current to the organic EL element is reduced continuously or stepwise. 6. The method of driving an organic EL panel according to claim 5, wherein the time until the organic EL element reaches a non-light emitting state can be arbitrarily changed.

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