JPWO2015178336A1 - Lighting device - Google Patents

Abstract

In addition to avoiding inconvenience caused by failure of the light emitting element, light emission unevenness of the light emitting element is improved. The surface light emitting module (10) includes a path (41) connected in series to the current circuit (50), a surface light emitting element (31) interposed in the path (41), and a surface light emitting element (31) in parallel. The path (43) connected to the sheet, the sheet-like load (45) inserted in the path (43), and any one of the path (41) and the path (43) can be made conductive. When the voltage applied to both ends of the switch circuit (47) and the surface light emitting module (10) is included in a predetermined range, the path (41) is turned on, the path (43) is turned off, and the surface light emitting module When the voltage applied to both ends of (10) is not included in the predetermined range, the control circuit that drives the switch circuit (47) so that the path (41) is turned off and the path (43) is turned on. (49). The load (45) is in direct or indirect contact with the current circuit.

Description

  The present disclosure relates to a lighting device, and more particularly, to a lighting device having a planar light emitting element.

  Conventionally, techniques for controlling light emitting elements such as OLED (Organic Light Emitting Diode) and LEDs (Light Emitting Diode) are known. For example, Japanese Unexamined Patent Application Publication No. 2007-165161 (Patent Document 1) discloses an LED lighting device for reducing a decrease in luminance caused by an open failure of an LED. As a specific means for solving this, the LED illumination device bypasses the current in parallel with the LEDs connected in series, and lights other LEDs than the failed LED.

JP 2007-165161 A

  By the way, an illumination device including a light emitting element such as an OLED or an LED is often provided with a current circuit that controls a current flowing through the light emitting element so that the luminance of the light emitting element is constant. In such a lighting device, a large voltage is applied to the current circuit due to a short circuit failure or an open failure of the light emitting element, and the current circuit may fail. For this reason, the illuminating device which can avoid the failure of the current circuit accompanying the failure of a light emitting element is desired.

  In addition, in a light emitting element such as an OLED, light emission unevenness occurs due to a temperature difference in the surface of the light emitting element due to heat generation in the current circuit. The OLED becomes brighter as the temperature of the light emitting surface is higher, and darker as the temperature of the light emitting surface is lower. Such luminance unevenness is a problem peculiar to planar light emitting elements such as OLEDs. Therefore, the LED lighting device disclosed in Patent Document 1 cannot solve this problem.

  The disclosure in the present application has been made to solve the above-described problems, and an object in one aspect is to avoid inconvenience caused by the failure of the light emitting element and to improve the light emission unevenness of the light emitting element. It is to provide a lighting device that can.

  According to one embodiment, a lighting device is provided that includes a current circuit and a surface emitting module connected in series to the current circuit. The surface light emitting module includes a first path connected in series to the current circuit, a surface light emitting element interposed in the first path, a second path connected in parallel to the surface light emitting element, and a second path. A sheet-like load inserted in the path, a switch circuit capable of bringing one of the first path and the second path into a conductive state, and a voltage applied to both ends of the surface emitting module is predetermined. When included in the range, the switch circuit is driven so that the first path is turned on and the second path is turned off, and the voltage applied to both ends of the surface emitting module is included in the predetermined range. And a control circuit that drives the switch circuit so that the first path is turned off and the second path is turned on. The sheet-like load is in direct or indirect contact with the current circuit.

  In one aspect, it is possible to avoid inconvenience caused by the failure of the light emitting element and to improve uneven light emission of the light emitting element.

  The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention taken in conjunction with the accompanying drawings.

It is a front view which shows the surface emitting module according to Embodiment 1. It is arrow sectional drawing in the II-II line | wire of FIG. It is the figure which showed visually the electric current which flows into the illuminating device according to Embodiment 1 when a surface emitting element is operate | moving normally. It is the figure which showed visually the electric current which flows into the illuminating device according to Embodiment 1 immediately after a surface light emitting element fails. It is the figure which showed visually the electric current which flows into the illuminating device according to Embodiment 1 when the failure of a surface emitting element is detected and a switch is switched. It is a circuit diagram of the surface emitting module corresponding to the short circuit failure of the surface emitting element. It is a circuit diagram of the surface emitting module corresponding to the open failure of the surface emitting element. It is a circuit diagram of the surface emitting module corresponding to both the short circuit failure and the open failure of the surface emitting element. It is a front view which shows the illuminating device according to Embodiment 1. FIG. It is arrow sectional drawing in the VV line | wire of FIG. It is a front view which shows the illuminating device according to Embodiment 2. FIG. It is arrow sectional drawing in the VII-VII line of FIG. FIG. 6 is a circuit diagram of a lighting device according to a third embodiment.

  Hereinafter, the present embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. Each embodiment described below and / or each modification may be selectively combined.

<Embodiment 1>
[Configuration of Surface Emitting Module 10]
With reference to FIG. 1 and FIG. 2, surface emitting module 10 included in lighting device 100 described later according to Embodiment 1 will be described. FIG. 1 is a front view showing the surface emitting module 10 and shows a state when the surface emitting module 10 is viewed from the back surface 19 side of the surface emitting module 10. 2 is a cross-sectional view taken along the line II-II in FIG.

  The surface light emitting module 10 in the present embodiment includes a transparent substrate 11 (cover layer), a surface light emitting element 31 formed on the transparent substrate 11, and a load 45 formed on the surface light emitting element 31. As an example, the surface emitting module 10 has a size of about 10 cm in length and width.

  The surface emitting module 10 includes a path 41, a path 43, a switch circuit 47, and a control circuit 49 in addition to the surface light emitting element 31 and the load 45, as shown in FIG. In FIG. 2, the surface light emitting element 31 includes an anode (anode) 14, an organic layer 15, a cathode (cathode) 16, a sealing member 17, and an insulating layer 18.

  The transparent substrate 11 forms the light emitting surface 12 (surface) of the surface light emitting module 10. The anode 14, the organic layer 15, and the cathode 16 are sequentially stacked on the back surface 13 of the transparent substrate 11. The sealing member 17 forms the back surface 19 of the surface emitting module 10.

  A transparent member is used as a member constituting the transparent substrate 11. As the material, for example, a light transmissive film substrate such as polyethylene terephthalate (PET) or polycarbonate (PC) is used. Various glass substrates may be used for the transparent substrate 11.

  In addition, polyimide, polyethylene naphthalate (PEN), polystyrene (PS), polyethersulfone (PES), polypropylene (PP), etc. are used as the light transmissive film substrate.

  The anode 14 is a conductive film having transparency. In order to form the anode 14, ITO (Indium Tin Oxide) or the like is formed on the transparent substrate 11 by sputtering or the like. As another material used for the anode 14, polyethylenedioxythiophene (PEDOT) is used.

  The organic layer 15 (light emitting unit) can generate light (visible light) when power is supplied. The organic layer 15 may be composed of a single light emitting layer, or may be composed of a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and the like that are sequentially laminated. .

  The cathode 16 is, for example, aluminum (AL). The cathode 16 is formed so as to cover the organic layer 15 by a vacuum deposition method or the like. In order to pattern the cathode 16 into a predetermined shape, a mask may be used during vacuum deposition. Other materials for the cathode 16 include lithium fluoride (LiF), a stack of Al and Ca, a stack of Al and LiF, a stack of Al and Ba, and the like.

  An insulating layer 18 is provided between the cathode 16 and the anode 14 so that the cathode 16 and the anode 14 are not short-circuited. The insulating layer 18 is formed in a desired pattern so as to cover a portion that insulates the anode 14 and the cathode 16 from each other using a photolithography method or the like after, for example, a SiO 2 film is formed using a sputtering method.

  The sealing member 17 is made of an insulating resin or glass substrate. The sealing member 17 is formed to protect the organic layer 15 from moisture and the like. The sealing member 17 seals substantially the whole of the anode 14, the organic layer 15, and the cathode 16 (a member provided inside the surface emitting module 10) on the transparent substrate 11. A part of the anode 14 is exposed from the sealing member 17 for electrical connection.

  The sealing member 17 has a gas barrier property by laminating a plurality of inorganic thin films such as SiO2, AL2O3, SiNx and a flexible acrylic resin thin film on a film of PET, PEN, PS, PES, polyimide, etc. What is provided with is used. Gold, silver, copper, or the like may be further laminated on the electrode portion 21 and the electrode portion 22.

  A portion (left side in FIG. 2) exposed from the sealing member 17 of the anode 14 constitutes an electrode portion 21 (for anode). The electrode portion 21 and the anode 14 are made of the same material. The electrode portion 21 is located on the outer periphery of one side surface of the surface emitting module 10. The portion of the cathode 16 exposed from the sealing member 17 (on the right side in FIG. 2) constitutes an electrode portion 22 (for the cathode). The electrode part 22 and the cathode 16 are made of the same material. The electrode part 22 is also located on the other outer periphery of the surface emitting module 10.

  The electrode part 21 and the electrode part 22 are located on the opposite sides of the organic layer 15. A wiring pattern (not shown) is attached to the electrode portion 21 and the electrode portion 22 using soldering (silver paste) or the like.

  The load 45 is configured by a sheet-like resistor. The load 45 is provided so as to directly or indirectly contact a current circuit 50 described later. The load 45 is provided so as to be overlapped on one surface of the surface light emitting element 31. More specifically, the load 45 is provided on the surface opposite to the light emitting surface of the surface light emitting element 31. As will be described later, when the surface light emitting element 31 fails, the load 45 bypasses the current flowing in the surface light emitting element 31 before the failure. Details of the load 45 will be described later.

  The organic layer 15 constituting the surface light emitting element 31 of the surface light emitting module 10 configured as described above is supplied with an electrode unit 21, an electrode unit 22, an anode 14, and an external power supply device (a constant current source). Power is supplied through the cathode 16. The light generated in the organic layer 15 is taken out from the light emitting surface 12 (surface) through the anode 14 and the transparent substrate 11.

[Circuit Configuration of Lighting Device 100]
Hereinafter, an outline of lighting apparatus 100 according to the first embodiment will be described with reference to FIGS. 3 to 5. FIG. 3 is a diagram visually showing a current flowing through the lighting device 100 when the surface light emitting element 31 is operating normally. FIG. 4 is a diagram visually showing the current flowing through the lighting device 100 immediately after the surface light emitting element 31 has failed. FIG. 5 is a diagram visually showing a current flowing through the lighting device 100 after a predetermined time has elapsed since the surface light emitting element 31 has failed.

  As shown in FIG. 3, the lighting device 100 includes a surface emitting module 10, a voltage source 40, and a current circuit 50. The surface emitting module 10 and the current circuit 50 are made of a flexible material so that the lighting device 100 has flexibility (flexibility). As an example, the lighting device 100 is configured so that its thickness is within 1 mm.

  The surface emitting module 10 is connected in series with the voltage source 40 and the current circuit 50. The surface emitting module 10 includes a surface light emitting element 31, a path 41 (first path) connected in series to the current circuit 50, a path 43 (second path) connected in parallel to the path 41, a load 45, a switch circuit 47, and a control circuit 49. The surface light emitting element 31 includes, for example, an OLED. The surface light emitting element 31 is inserted in the path 41. The load 45 is inserted in the path 43. The switch circuit 47 includes a switch 47A inserted in the path 41 and a switch 47B inserted in the path 43.

  The voltage source 40 supplies a voltage to the surface emitting module 10 and the current circuit 50. The current circuit 50 includes a constant current circuit for supplying a constant current to the surface emitting module 10. Thereby, the brightness | luminance of the surface emitting module 10 can be kept constant.

  By driving the switch circuit 47, the control circuit 49 can set one of the path 41 and the path 43 to a conductive state and the other to a non-conductive state. That is, the control circuit 49 can switch the path to be turned on between the path 41 and the path 43. As shown in FIG. 3, when the surface light emitting element 31 is normal, the control circuit 49 drives the switch circuit 47 so that the path 41 is turned on and the path 43 is turned off. . Thereby, the voltage from the voltage source 40 is applied to the surface emitting module 10 and the current circuit 50. Along with this, a current flows to the surface light emitting element 31, and the surface light emitting element 31 emits light.

  Illumination device 100 according to the present embodiment prevents current circuit 50 from failing due to failure of surface light emitting element 31. Hereinafter, a specific method for realizing this will be described. In addition, the failure of the surface light emitting element 31 according to the present embodiment includes a short failure and an open failure. In addition, the short fault in this Embodiment means the fault which the surface emitting element 31 short-circuits. Further, the open failure in the present embodiment refers to a failure in which the surface light emitting element 31 is disconnected. Hereinafter, after describing the operation outline of the illumination device 100 when the surface light emitting element 31 has a short circuit failure, the operation outline of the illumination device 100 when the surface light emission element 31 has an open failure will be described.

(When the surface light emitting element 31 has a short circuit failure)
In order to simplify the description, the voltage applied from the voltage source 40 is defined as V _ALL , the voltage applied to the surface light emitting module 10 is defined as V _F, and the voltage applied to the current circuit 50 is defined as V _I. In this case, V _ALL = V _F + V _I is established.

As shown in FIG. 4, when the surface light-emitting element 31 is short-circuited, the voltage V _F according to the surface-emitting module 10 becomes zero. Accordingly, the voltage _{V I} applied to the current circuit 50 _is increased from _V ALL -V _F to _{V ALL.} That is, the voltage V _I applied to the current circuit 50 increases by the amount of the voltage V _F applied to the surface light emitting element 31 before the failure of the surface light emitting element 31.

  When the voltage applied to the current circuit 50 exceeds a certain voltage (hereinafter, also referred to as “allowable voltage”), the current circuit 50 generates heat and consequently fails. In particular, when the surface emitting module 10 is thinned, the allowable voltage of the current circuit 50 is reduced, so that the risk of failure of the current circuit 50 is increased.

For this reason, as shown in FIG. 5, lighting device 100 according to the present embodiment bypasses the current flowing in path 41 to path 43 when surface light emitting element 31 is short-circuited. Accordingly, the voltage drop at the load 45 (= _{V F)} occurs, the voltage _{V I} according current circuit 50 _decreases from _{V ALL} the _V ALL -V _F. Therefore, the lighting device 100 can suppress the voltage applied to the current circuit 50 within a range that does not exceed the allowable voltage, and can prevent a failure of the current circuit 50. Typically, the resistance value of the load 45 is determined so that the voltage applied to the current circuit 50 does not change before and after the surface light emitting element 31 is short-circuited.

  Whether or not the surface light emitting element 31 has a short circuit failure is determined by, for example, the control circuit 49 monitoring the voltage applied to the surface light emitting module 10. More specifically, when the surface light emitting element 31 is short-circuited, the voltage applied to the surface light emitting module 10 is reduced. For this reason, the control circuit 49 determines that the surface light emitting element 31 has a short circuit failure when the voltage applied to both ends of the surface light emitting module 10 is not included in the predetermined range. In this case, the control circuit 49 drives the switch circuit 47 so as to set the path 41 in a non-conductive state and to set the path 43 in a conductive state.

  In addition, the control circuit 49 determines that the surface light emitting element 31 is normal when the voltage applied to both ends of the surface light emitting module 10 is included in a predetermined range. In this case, the control circuit 49 drives the switch circuit 47 so that the path 41 is turned on and the path 43 is turned off.

  Note that the predetermined range in the present embodiment includes a range having only a lower limit, a range having only an upper limit, and a range having both a lower limit and an upper limit. In particular, when the designer of the lighting device 100 intends to detect a short circuit failure, a lower limit is set in a predetermined range. That is, the control circuit 49 determines that the surface light emitting element 31 has a short circuit failure when the voltage applied to both ends of the surface light emitting module is lower than the lower limit voltage. In this case, the control circuit 49 drives the switch circuit 47 so that the path 41 is turned off and the path 43 is turned on.

(When the surface light emitting element 31 has an open failure)
The illuminating device 100 may include a plurality of surface emitting modules 10 as illustrated in FIGS. 11 and 12 described later. When a plurality of surface light emitting modules 10 are connected in series, there is a possibility that all the surface light emitting elements 31 are extinguished due to an open failure of one surface light emitting element 31. For this reason, the illuminating device 100 according to the present embodiment prevents the other normal surface light emitting elements 31 from being turned off even if one surface light emitting element 31 has an open failure.

Surface light-emitting element 31 when the open failure, the voltage V _F according to the surface-emitting module 10 is increased. That is, the voltage _{V F} applied to the surface-emitting module 10 _is increased from _V ALL -V _I to _{V ALL.} When the voltage applied to both ends of the surface emitting module 10 is not included in the predetermined range, the control circuit 49 determines that the surface emitting element 31 has an open failure. When the designer of the lighting device 100 intends to detect an open failure, an upper limit is set in a predetermined range. That is, the control circuit 49 determines that the surface light emitting element 31 has an open failure when the voltage applied to both ends of the surface light emitting module 10 becomes higher than the upper limit voltage. In this case, the control circuit 49 drives the switch circuit 47 so that the path 41 is turned off and the path 43 is turned on.

[Example of mounting surface emitting module 10]
A mounting example of the surface emitting module 10 will be described with reference to FIGS. Various mounting examples of the surface emitting module 10 are conceivable. Below, some of them are demonstrated.

(Surface emitting module 10 for short circuit failure)
FIG. 6 is a circuit diagram of the surface light emitting module 10 corresponding to a short circuit failure of the surface light emitting element 31. The surface light emitting module 10 in FIG. 6 prevents the current circuit 50 from failing by bypassing the current flowing through the surface light emitting element 31 to the load 45 even when the surface light emitting element 31 has a short circuit failure. The surface light emitting module 10 includes a surface light emitting element 31, a path 41, a path 43, a load 45, a switch circuit 47, and a control circuit 49 as main components.

  The surface light emitting element 31 is connected between the node N11 and the node N14. The load 45 is connected between the node N11 and the node N12.

  Switch circuit 47 includes a switch 47A and a switch 47B. The switch 47A is configured by, for example, a transistor Q11 (NPN type). The collector C of the transistor Q11 is connected to the node N14. The base B of the transistor Q11 is connected to the node N12. The emitter E of the transistor Q11 is connected to the node N13.

  The switch 47B is configured by, for example, a transistor Q12 (NPN type). The collector C of the transistor Q12 is connected to the node N12. The base B of the transistor Q12 is connected to the node N15. The emitter E of the transistor Q12 is connected to the node N13.

  Control circuit 49 includes resistors R11 to R14. Resistor R11 is connected between nodes N11 and N12. Resistor R12 is connected between nodes N12 and N13. Resistor R13 is connected between nodes N14 and N15. Resistor R14 is connected between nodes N13 and N15.

  Hereinafter, details of the operation of the control circuit 49 will be described. When a voltage is applied to the surface light emitting module 10, the voltage applied to both ends of the surface light emitting element 31 (that is, between the anode and the cathode) gradually increases. As an example, the surface light emitting element 31 generates a voltage of about 5 to 7V. At the same time, the voltage applied to the resistors R11 and R12 gradually increases.

  At this time, the voltage applied between the base B and the emitter E of the transistor Q11 is equal to the voltage applied to the resistor R12. Therefore, if the voltage applied to the resistor R12 exceeds a predetermined voltage, a current flows between the collector C and the emitter E of the transistor Q11. Begins to flow. That is, the path 41 is switched from the non-conductive state to the conductive state. Along with this, a current flows through the surface light emitting element 31, and the surface light emitting element 31 emits light.

  In the following, for the sake of simplicity, setting the path 41 to be conductive is also referred to as turning on the transistor Q11, and setting the path 41 to be non-conductive is also referred to as turning off the transistor Q11. Similarly, setting the path 43 in a conductive state is also referred to as turning on the transistor Q12, and setting the path 43 in a non-conductive state is also referred to as turning off the transistor Q12.

  The timing at which the transistor Q11 is turned on can be adjusted by the ratio between the resistance value of the resistor R11 and the resistance value of the resistor R12. This is because the voltage applied to the resistor R12 is determined by this ratio. As an example, the resistance value of the resistor R11 and the resistance value of the resistor R12 are adjusted so that the transistor Q11 is turned on when the voltage applied to the surface light emitting element 31 is 3 V or higher. Similarly, the timing at which the transistor Q12 is turned on can be adjusted by the ratio between the resistance value of the resistor R13 and the resistance value of the resistor R14. The resistance values of the resistors R11 to R14 are adjusted so that the transistor Q11 is turned on and the transistor Q12 is turned off when the surface light emitting element 31 is normal.

As described above, when the surface light-emitting element 31 is short-circuited, the voltage V _F according to the surface-emitting module 10 is lowered. Along with this, the voltage applied to the resistor R12 decreases. For this reason, since the voltage applied between the base B and the emitter E of the transistor Q11 is lower than the predetermined voltage, the transistor Q11 is turned off.

  Along with this, a current flows through the resistor R13 and the resistor R14, and a voltage is applied to the resistor R14. That is, a voltage is applied between the base B and the emitter E of the transistor Q12. As a result, the transistor Q12 is turned on, and a current flows through the load 45. Thus, the lighting device 100 causes the voltage applied to the current circuit 50 to be distributed to the load 45 by causing a voltage drop at the load 45. Thereby, since the voltage concerning the current circuit 50 can be suppressed within the range of the allowable voltage, the lighting apparatus 100 can prevent the failure of the current circuit 50 due to the short-circuit failure of the surface light emitting element 31.

(Surface emitting module 10 corresponding to open failure)
With reference to FIG. 7, another mounting example of the surface emitting module 10 will be described. FIG. 7 is a circuit diagram of the surface light emitting module 10 corresponding to the open failure of the surface light emitting element 31. In the surface light emitting module 10 in FIG. 7, even when the surface light emitting element 31 has an open failure, the current flowing in the surface light emitting element 31 is bypassed to the load 45 so that the current flows to the surface light emitting element 31 that has not failed. To prevent all the surface light emitting elements 31 from being turned off. The surface light emitting module 10 includes a surface light emitting element 31, a path 41, a path 43, a load 45, a switch circuit 47, and a control circuit 49 as main components.

  Switch circuit 47 includes a switch 47A and a switch 47B. The switch 47A is formed of, for example, a transistor Q21 (NPN type). The collector C of the transistor Q21 is connected to the surface light emitting element 31. The base B of the transistor Q21 is connected to the node N22. The emitter E of the transistor Q21 is connected to the node N23.

  The switch 47B is formed of, for example, a transistor Q22 (NPN type). The collector C of the transistor Q22 is connected to the load 45. The base B of the transistor Q22 is connected to the node N24. The emitter E of the transistor Q22 is connected to the node N23.

  The surface light emitting element 31 is connected between the node N21 and the collector C of the transistor Q21. Load 45 is connected between node N21 and collector C of transistor Q22.

  Control circuit 49 includes resistors R21 to R24. Resistor R21 is connected between nodes N21 and N22. Resistor R22 is connected between nodes N22 and N23. Resistor R23 is connected between nodes N22 and N24. Resistor R24 is connected between nodes N23 and N24.

  Hereinafter, details of the operation of the control circuit 49 will be described. When a voltage is applied to the surface light emitting module 10, the voltage applied to both ends of the surface light emitting element 31 (that is, between the anode and the cathode) gradually increases. As an example, the surface light emitting element 31 generates a voltage of about 5 to 7V. At the same time, the voltage applied to the resistors R21 and R22 also gradually increases.

  At this time, since the voltage applied between the base B and the emitter E of the transistor Q21 is equal to the voltage applied to the resistor R22, the transistor Q21 is turned on when the voltage applied to the resistor R22 exceeds a predetermined voltage. That is, the path 41 is switched from the non-conductive state to the conductive state, and accordingly, the surface light emitting element 31 emits light.

  Similarly to the above, the timing at which the transistor Q21 is turned on can be adjusted by the ratio between the resistance value of the resistor R21 and the resistance value of the resistor R22. As an example, the resistance value of the resistor R21 and the resistance value of the resistor R22 are adjusted so that the transistor Q21 is turned on when the voltage applied to the surface light emitting element 31 is 3 V or higher. Similarly, the timing at which the transistor Q22 is turned on can be adjusted by the ratio of the resistance value of the resistor R21, the resistance value of the resistor R23, and the resistance value of the resistor R24. The resistance values of the resistors R21 to R24 are adjusted so that the transistor Q21 is turned on and the transistor Q22 is turned off when the surface light emitting element 31 is normal.

As described above, when the surface light-emitting element 31 has an open failure, the voltage V _F according to the surface-emitting module 10 becomes larger. Along with this, the voltage applied to the resistor R24 increases. For this reason, since the voltage applied between the base B and the emitter E of the transistor Q22 exceeds a predetermined voltage, the transistor Q22 is turned ON. As an example, the resistance value of the load 45, when the transistor Q22 is turned ON, the voltage _{V F} is adjusted to be above 7V (e.g., 8V). This prevents a large voltage from being applied to the current circuit 50.

  As described above, since the current is bypassed to the load 45, even when the surface light emitting element 31 has an open failure, the current can be passed through the other surface light emitting modules 10 connected in series. That is, the lighting device 100 can prevent the other surface light emitting elements 31 from being turned off even when one surface light emitting element 31 has an open failure.

(Surface emitting module 10 corresponding to short-circuit failure and open failure)
With reference to FIG. 8, still another mounting example of the surface emitting module 10 will be described. FIG. 8 is a circuit diagram of the surface emitting module 10 corresponding to both a short circuit failure and an open failure of the surface light emitting element 31. The surface emitting module 10 in FIG. 8 prevents the current circuit 50 from failing by bypassing the current flowing through the surface light emitting element 31 to the load 45 even when the surface light emitting element 31 has a short circuit failure. . Further, even if the surface light emitting module 31 has an open failure, the surface light emitting module 10 bypasses the current flowing through the surface light emitting element 31 to the load 45 so that a current is supplied to the surface light emitting element 31 that has not failed. To prevent all the surface light emitting elements 31 from being turned off.

  The surface light emitting module 10 includes a surface light emitting element 31, a path 41, a path 43, a load 45, a switch circuit 47, and a control circuit 49 as main components. Switch circuit 47 includes a switch 47A, a switch 47B, and a switch 47C.

  The switch 47A is formed of, for example, a transistor Q31 (NPN type). The collector C of the transistor Q31 is connected to the node N34. The base B of the transistor Q31 is connected to the node N32. The emitter E of the transistor Q31 is connected to the node N33.

  The switch 47B is formed of, for example, a transistor Q32 (NPN type). The collector C of the transistor Q32 is connected to the node N32. The base B of transistor Q32 is connected to node N35. The emitter E of the transistor Q32 is connected to the node N33.

  The switch 47C is formed of, for example, a transistor Q33 (NPN type). The collector C of the transistor Q32 is connected to the node N32. The base B of transistor Q32 is connected to node N36. The emitter E of the transistor Q32 is connected to the node N33.

  The surface light emitting element 31 is connected between the node N31 and the node N34. The load 45 is connected between the node N31 and the node N32.

  Control circuit 49 includes resistors R31 to R36. Resistor R31 is connected between nodes N31 and N32. Resistor R32 is connected between nodes N32 and N33. Resistor R33 is connected between nodes N34 and N35. Resistor R34 is connected between nodes N33 and N35. Resistor R35 is connected between nodes N31 and N36. Resistor R36 is connected between nodes N33 and N36.

  Hereinafter, details of the operation of the control circuit 49 will be described. When a voltage is applied to the surface light emitting module 10, the voltage applied to both ends of the surface light emitting element 31 (that is, between the anode and the cathode) gradually increases. As an example, the surface light emitting element 31 generates a voltage of about 5 to 7V. At the same time, the voltage applied to the resistors R31 and R32 also gradually increases.

  The voltage applied between the base B and the emitter E of the transistor Q31 is equal to the voltage applied to the resistor R32. For this reason, when the voltage applied to the resistor R32 exceeds a predetermined voltage, the transistor Q31 is turned on. Along with this, a current flows through the surface light emitting element 31, and the surface light emitting element 31 emits light.

  The timing at which the transistor Q31 is turned on can be adjusted by the ratio between the resistance value of the resistor R31 and the resistance value of the resistor R32. This is because the voltage applied to the resistor R32 is determined by this ratio. As an example, the resistance value of the resistor R31 and the resistance value of the resistor R32 are adjusted so that the transistor Q31 is turned on when the voltage applied to the surface light emitting element 31 is 3 V or higher. Similarly, the timing at which the transistor Q32 is turned on can be adjusted by the ratio between the resistance value of the resistor R33 and the resistance value of the resistor R34. Similarly, the timing at which the transistor Q33 is turned on can be adjusted by the ratio between the resistance value of the resistor R35 and the resistance value of the resistor R36. The resistance values of the resistors R31 to R36 are adjusted so that the transistor Q31 is turned on and the transistors Q32 and Q33 are turned off when the surface light emitting element 31 is normal.

As described above, when the surface light-emitting element 31 is short-circuited, the voltage V _F according to the surface-emitting module 10 is lowered. Along with this, the voltage applied to the resistor R32 decreases. For this reason, since the voltage applied between the base B and the emitter E of the transistor Q31 is lower than the predetermined voltage, the transistor Q31 is turned off.

  Along with this, a current flows through the resistor R33 and the resistor R34, and a voltage is applied to the resistor R34. As a result, a voltage is applied between the base B and the emitter E of the transistor Q32, the transistor Q32 is turned on, and a current flows through the load 45. The lighting device 100 can distribute the voltage applied to the current circuit 50 to the load 45 by causing a voltage drop at the load 45. Thereby, the failure of the current circuit 50 due to the short failure of the surface light emitting element 31 can be prevented.

Further, when the surface light-emitting element 31 has an open failure, the voltage V _F according to the surface-emitting module 10 becomes larger. Along with this, the voltage applied to the resistor R36 increases. As a result, the voltage applied between the base B and the emitter E of the transistor Q33 exceeds a predetermined voltage, so that the transistor Q33 is turned on. As a result, more current flows through the load 45. As an example, the resistance value of the load 45, when the transistor Q33 is turned ON, the voltage _{V F} is adjusted to be above 7V (e.g., 8V). This prevents a large voltage from being applied to the current circuit 50.

  As described above, since the current is bypassed to the load 45, even when the surface light emitting element 31 has an open failure, the current can be passed through the other surface light emitting modules 10 connected in series. That is, the lighting device 100 can prevent the other surface light emitting elements 31 from being turned off even when one surface light emitting element 31 has an open failure.

[Load 45]
The details of the load 45 will be described with reference to FIGS. 1 and 2 again. The luminance of the surface light emitting module 10 is affected by the temperature in the surface. More specifically, the brightness of the surface light emitting element 31 increases as the temperature increases, and decreases as the temperature decreases. Since the power source such as the voltage source 40 and the current circuit 50 generates heat, the temperature in the region in the surface emitting module 10 closer to the position where the power source is disposed becomes higher. Thereby, luminance unevenness caused by the temperature difference occurs in the surface emitting module 10.

  In order to eliminate this luminance unevenness, the load 45 is composed of a sheet-like resistor (hereinafter also referred to as “sheet resistor”), and is provided so as to diffuse the heat generated from the current circuit 50 to the sheet resistor. That is, the sheet resistance is provided so as to contact the current circuit 50 directly or indirectly. In other words, the sheet resistance is provided so that heat generated from the current circuit 50 is conducted to the sheet resistance. That is, the sheet resistance may be provided so as to be in direct contact with the current circuit 50, or another object may be provided between the sheet resistance and the current circuit 50.

  Further, the sheet resistance is provided so as to overlap on one surface of the surface light emitting element 31. More specifically, the sheet resistance is provided on the surface opposite to the light emitting surface of the surface light emitting element 31. Thereby, the sheet resistance can diffuse and dissipate heat in the surface light emitting module 10, and a temperature difference in the surface light emitting module 10 can be reduced. As a result, luminance unevenness in the surface emitting module 10 is reduced.

  In one aspect, the sheet resistance is configured such that its thermal conductivity is higher than the thermal conductivity of the surface light emitting element 31. Thereby, the heat in the surface emitting module 10 can be more reliably diffused to the sheet resistance. The sheet resistance is made of, for example, copper, nickel, manganese, chromium, and other metal alloys having high thermal conductivity. Further, the sheet resistance is provided so as to overlap a part or all of the light emitting region of the surface light emitting element 31 (that is, the region of the organic layer 15 in FIG. 1). By providing the sheet resistance in this way, heat in the surface emitting module 10 is effectively diffused into the sheet resistance.

  In another aspect, the circuit board 60 on which the current circuit 50 is mounted has a heat dissipation pattern for the current circuit 50 in the board. A conductive adhesive or conductive grease may be used between the sheet resistance and the circuit board. This stabilizes the contact and thermal conductivity between the sheet resistance and the circuit board.

  In FIGS. 1 and 2, the sheet resistance is configured as a member different from the surface light emitting element 31, but the sheet resistance may be configured inside the surface light emitting element 31. That is, the sheet resistance may be configured integrally with the surface light emitting element 31.

[Main Configuration of Lighting Device 100]
Hereinafter, the main configuration of the lighting device 100 will be described with reference to FIGS. 9 and 10A. FIG. 9 is a front view showing the lighting device 100, and shows a state when the lighting device 100 is viewed from the front side of the lighting device 100. 10 is a cross-sectional view taken along line VV in FIG.

  The lighting device 100 includes a surface light emitting module 10, a load 45, a current circuit 50, and a circuit board 60. The surface emitting module 10, the load 45, the current circuit 50, and the circuit board 60 are configured by members having flexibility so that the lighting device 100 has flexibility. As an example, the lighting device 100 is configured so that its thickness is within 1 mm.

  The current circuit 50 is electrically connected to the surface emitting module 10 so that a constant current is supplied to the surface emitting module 10. As described above, when the surface light emitting element 31 is short-circuited, the current flowing in the surface light emitting module 10 is bypassed to the load 45.

  The load 45 (that is, the sheet resistance) is provided so as to directly or indirectly contact the current circuit 50 in order to diffuse the heat generated from the current circuit 50 to the load 45. That is, the load 45 may be provided so as to contact the current circuit 50, or another object (for example, the circuit board 60) may be provided between the load 45 and the current circuit 50. Note that the arrangement of the circuit board 60 and the current circuit 50 in FIG. 10A may be reversed and the arrangement shown in FIG. In this case, the current circuit 50 and the load 45 are in direct contact.

  A circuit configuration such as the control circuit 49 described above is mounted on the circuit board 60. In addition, by mounting wiring on the current circuit 50, the load 45, the current circuit 50, and the lighting device 100 are electrically connected to each other.

<Embodiment 2>
Hereinafter, with reference to FIG. 11 and FIG. 12, illumination device 100A according to the second embodiment will be described. FIG. 11 is a front view showing the lighting device 100A, and shows a state when the lighting device 100A is viewed from the front side of the lighting device 100A. 12 is a cross-sectional view taken along line VII-VII in FIG. Lighting device 100A according to the present embodiment is different from lighting device 100 according to the first embodiment in that it includes a plurality of surface emitting modules. Since other points are similar to those of lighting apparatus 100A according to the first embodiment, description thereof will not be repeated.

  The illumination device 100A includes a surface light emitting module 10A, a surface light emitting module 10B, a load 45A, a load 45B, a current circuit 50, and a circuit board 60. The surface emitting module 10A, the surface emitting module 10B, the load 45A, the load 45B, the current circuit 50, and the circuit board 60 are configured by members having flexibility so that the lighting device 100A has flexibility. The As an example, the lighting device 100A is configured to have a thickness of 1 mm or less.

  The surface emitting module 10A and the surface emitting module 10B are connected in series so that a constant current is supplied to each. Since the surface light emitting module 10A and the surface light emitting module 10B are connected in series, when one of the surface light emitting modules fails to open, both the surface light emitting module 10A and the surface light emitting module 10B may be extinguished. There is. For this reason, lighting apparatus 100A according to the present embodiment does not turn off other normal surface emitting modules even when one of the surface emitting modules has an open failure. That is, the lighting device 100A bypasses the current to the load 45A when the surface emitting module 10A fails. The lighting device 100A bypasses the current to the load 45B when the surface emitting module 10B fails. Since the details of the operation of the lighting device 100A when the surface light emitting module 10A is short-circuited are the same as those of the lighting device 100 described above, the description will not be repeated.

<Embodiment 3>
Hereinafter, with reference to FIG. 13, illumination device 100B according to the third embodiment will be described. FIG. 13 is a circuit diagram of the lighting device 100B. In lighting apparatus 100B according to the present embodiment, the configuration of switch circuit 47 is different from that of lighting apparatus 100 according to the first embodiment. Since other points are similar to those of lighting apparatus 100 according to the first embodiment, description thereof will not be repeated.

  As shown in FIG. 13, the switch circuit 47 included in the illumination device 100B includes a single-pole double-throw switch 47D. More specifically, one end of the switch 47D can be electrically connected to the path 41 or the path 43. With this configuration, the switch circuit 47 can be configured with one switch 47D, and thus the manufacturing cost can be reduced.

<Summary>
As described above, a lighting device including a current circuit and a surface emitting module connected in series to the current circuit is provided. The surface light emitting module includes a first path connected in series to the current circuit, a surface light emitting element interposed in the first path, a second path connected in parallel to the surface light emitting element, and a second path. A sheet-like load inserted in the path, a switch circuit capable of bringing one of the first path and the second path into a conductive state, and a voltage applied to both ends of the surface emitting module is predetermined. When included in the range, the switch circuit is driven so that the first path is turned on and the second path is turned off, and the voltage applied to both ends of the surface emitting module is included in the predetermined range. And a control circuit that drives the switch circuit so that the first path is turned off and the second path is turned on. The sheet-like load is in direct or indirect contact with the current circuit.

  Preferably, the predetermined range has the first voltage as the lower limit. The control circuit switches the first path to the non-conductive state and the second path to the conductive state when the voltage applied to both ends of the surface emitting module is lower than the first voltage. The switch circuit is driven so as to drive.

  Preferably, the predetermined range has a second voltage higher than the first voltage as an upper limit. The control circuit switches the first path to the non-conductive state and the second path to the conductive state when the voltage applied to both ends of the surface emitting module becomes higher than the second voltage. Drive.

  Preferably, the sheet-like load is provided so as to overlap with the surface opposite to the light emitting surface of the surface light emitting element.

Preferably, the thermal conductivity of the sheet-like load is higher than the thermal conductivity of the surface light emitting element.
Preferably, the sheet-like load is provided so as to overlap a part or all of the light emitting region of the surface light emitting element.

  Preferably, the current circuit and the surface emitting module are made of a flexible material.

  Preferably, the current circuit includes a constant current circuit for supplying a constant current to the surface emitting module.

  Preferably, the lighting device includes a plurality of surface light emitting modules connected in series to a current circuit.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 10A, 10B Surface light emitting module, 11 Transparent substrate, 12 Light emitting surface, 13 Back surface, 14 Anode, 15 Organic layer, 16 Cathode, 17 Sealing member, 18 Insulating layer, 19 Back surface, 21, 22 Electrode portion, 31 surface Light emitting element, 40 voltage source, 41, 43 path, 45, 45A, 45B load (sheet resistance), 47 switch circuit, 47A, 47B, 47C, 47D switch, 49 control circuit, 50 current circuit, 60 circuit board, 100, 100A, 100B illumination device, N11 to N36 nodes, Q11 to Q33 transistors, R11 to R36 resistors.

Claims (9)

A lighting device comprising a current circuit and a surface emitting module connected in series to the current circuit,
The surface emitting module is
A first path connected in series to the current circuit;
A surface light emitting element interposed in the first path;
A second path connected in parallel to the surface light emitting element;
A sheet-like load inserted in the second path;
A switch circuit capable of bringing either one of the first path and the second path into a conductive state;
When the voltage applied to both ends of the surface emitting module is included in a predetermined range, the switch circuit is driven so that the first path is in a conductive state and the second path is in a non-conductive state. When the voltage applied to both ends of the surface emitting module is not included in the predetermined range, the switch circuit is configured to set the first path in a non-conductive state and the second path in a conductive state. And a control circuit for driving
The lighting device, wherein the sheet-like load is in direct or indirect contact with the current circuit. The predetermined range has a first voltage as a lower limit;
When the voltage applied to both ends of the surface emitting module is lower than the first voltage, the control circuit sets the first path to a non-conductive state and sets the second path to a conductive state. The lighting device according to claim 1, wherein the switch circuit is driven so as to drive the switch circuit. The predetermined range has a second voltage higher than the first voltage as an upper limit,
When the voltage applied to both ends of the surface emitting module becomes higher than the second voltage, the control circuit sets the first path to a non-conductive state and sets the second path to a conductive state. The lighting device according to claim 2, wherein the switch circuit is driven to do so.   The lighting device according to any one of claims 1 to 3, wherein the sheet-like load is provided on a surface opposite to a light emitting surface of the surface light emitting element.   The lighting device according to claim 4, wherein a thermal conductivity of the sheet-like load is higher than a thermal conductivity of the surface light emitting element.   The lighting device according to claim 4 or 5, wherein the sheet-like load is provided so as to overlap a part or all of a light emitting region of the surface light emitting element.   The lighting device according to claim 1, wherein the current circuit and the surface light emitting module are made of a flexible material.   The lighting device according to claim 1, wherein the current circuit includes a constant current circuit for supplying a constant current to the surface emitting module.   The said illuminating device is an illuminating device of any one of Claims 1-8 provided with the said some surface emitting module connected in series with the said current circuit.

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