JP5355904B2 - Lighting device - Google Patents

Description

  The present invention relates to an illuminating device, and in particular, an illuminating device that emits light with a predetermined brightness by applying a current from a lighting circuit to a light emitting module configured by interposing a planar organic electroluminescent light emitting element between electrodes. About.

  A self-luminous organic electroluminescence element (hereinafter referred to as an organic EL element) uses an electroluminescence phenomenon, and therefore has few features such as little heat generation, light weight and thinness, and low driving voltage. doing.

  In recent years, there has been proposed an organic EL lighting device that illuminates a wide space such as a room using the organic EL element as a light source. In this organic EL lighting device, a lighting circuit is connected to an organic EL light emitting module in which organic EL elements are formed in a planar shape, and a direct current voltage is applied to control the current, thereby controlling the light emitting surface of the organic EL light emitting module to a predetermined level. Lights up with brightness to illuminate a wide space.

  FIG. 14 is a diagram showing a conventional lighting circuit for controlling the current flowing through the organic EL element. In FIG. 14, a resistor R3 is connected in series to the organic EL light emitting module 80, a flowing current Ila is detected as a voltage value across the resistor R3, and a difference from a preset reference value of Ila is amplified by a differential amplifier OP3. To the base of the switching transistor Q2. The switching transistor Q2 controls the current Ila flowing through the organic EL light emitting module 80 to be equal to the reference value.

  In general, the brightness when the organic EL light emitting module 80 is lit by applying a current Ils has a linear relationship with the current as shown by a straight line A shown in FIG. However, as indicated by the straight line B or C, brightness may vary due to individual variations even between the applied currents, even between the plurality of organic EL light emitting modules. In the case of a large illuminating device in which a plurality of light emitting modules are arranged side by side, there arises a problem that the brightness differs for each light emitting module. In addition, even if the same current is continuously applied to the same individual, the line A at the beginning of lighting changes as shown by the line B or C due to secular change, resulting in a constant brightness. It may not be possible to maintain.

  In order to solve these problems, the brightness of the organic EL light emitting module is detected by an optical sensor arranged close to the light emitting surface of the organic EL light emitting module, and the brightness of the organic EL element is adjusted by feeding back the detected brightness. However, there is a problem that the illumination light on the light emitting surface is blocked by the optical sensor and its wiring, and the illumination light cannot be uniformly emitted from the entire light emitting surface. In addition, when uneven light emission (brightness unevenness) occurs due to non-uniformity of the thickness of the organic EL light emitting layer, the brightness detected at the position where the photosensor is disposed may be a singular point.

  Conventionally, an example has been proposed in which the light emission amount of an organic EL element is detected by an optical sensor arranged for each organic EL element, and the luminance of the organic EL element is adjusted according to the light emission amount (see, for example, Patent Document 1). .

  However, in this example, each organic EL element is a display device that is independent as a pixel. When this method is applied to a lighting device, for example, when an optical sensor is provided in an electrode that interposes the organic EL element, This causes a problem that the amount of emitted light at that point cannot be measured accurately.

JP 2006-30317 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an illuminating device capable of uniformly lighting the entire light emitting surface with a predetermined brightness without being affected by individual variations or aging. And

The illuminating device of the present invention is an illuminating device that emits light by applying an electric current from a lighting circuit to a light emitting module configured by inserting a planar light emitting element between opposing electrodes, and is generated from the planar light emitting element. A light shielding body having an opening is laminated on the electrode located on the non-irradiation side of the light to be emitted, and the light of the planar light emitting element that is disposed close to and opposite to the opening and leaks through the opening A brightness detection unit that directly detects the current, and the lighting circuit applies the current to be applied if the light emitting module is lit brighter than a predetermined brightness based on the brightness detected by the brightness detection unit. If the light emitting module is lit darker than the predetermined brightness, the applied current is increased.

  With this configuration, when a current is applied from the lighting circuit to cause the light emitting module to emit light, the light emitting module is applied so as to be lit at a predetermined brightness based on the brightness of the light emitting module detected by the brightness detection unit. Since the current is controlled, it can be lit at a constant brightness without being affected by individual variations and aging. In addition, the brightness detection unit is disposed on the non-irradiation side of the planar light emitting element, detects light leaking from a minute opening provided in the light blocking body, and is a portion located at the opening of the planar light emitting element Therefore, the illumination light can be uniformly emitted from the entire light emitting surface. Furthermore, even when a plurality of light emitting modules are arranged side by side, it is possible to make the brightness of each light emitting module the same by aligning the reference values of the brightness.

The lighting device of the present invention is a lighting device that emits light by applying a current from a lighting circuit to a light-emitting module configured by interposing a planar light-emitting element between opposing electrodes, the planar light-emitting element The electrode located on the non-irradiation side of the light generated from the electrode has an opening, is disposed close to and opposite to the opening, and directly detects light of the planar light emitting element leaking through the opening The lighting circuit, based on the brightness detected by the brightness detection unit, if the light emitting module is lit brighter than a predetermined brightness, to reduce the current to be applied, If the light emitting module is lit darker than the predetermined brightness, the applied current is increased.

  With this configuration, when a current is applied from the lighting circuit to cause the light emitting module to emit light, the light emitting module has a predetermined brightness based on the brightness of the light emitting module detected by the brightness detecting unit as light leaking from the opening. Since the current to be applied is controlled so as to be turned on, the light can be turned on at a constant brightness without being affected by individual variations and aging. In addition, the brightness detector is arranged on the non-irradiation side of the planar light emitting element and detects light leaking from a minute opening provided in the electrode, so that the illumination light can be uniformly emitted from the entire light emitting surface. Can do. Furthermore, even when a plurality of light emitting modules are arranged side by side, it is possible to make the brightness of each light emitting module the same by aligning the reference values of the brightness.

  Further, the present invention provides the above-described lighting device, wherein the lighting device includes a plurality of the opening portions, the brightness detection units are provided in the same number as the opening portions, and the lighting circuit includes a plurality of light detection units detected by the brightness detection units. It includes one that calculates brightness and controls the current applied to the light emitting module based on the calculation result.

  With this configuration, a plurality of brightnesses of the light emitting module detected by the brightness detection unit are calculated, and the current applied to the light emitting module is controlled based on the calculation result. Can be lit at a predetermined brightness. In addition, even if there is uneven brightness in the light emitting module, the influence can be reduced by calculating the brightness of multiple parts of the light emitting module, and illumination light can be emitted uniformly from the entire light emitting surface. Become.

  Further, according to the present invention, in the illumination device, the calculation result includes an average value of the plurality of brightnesses.

  With this configuration, the average value of a plurality of brightness levels of the light emitting module detected by the brightness detection unit is calculated, and the current applied to the light emitting module is controlled based on the average value. Even if there is, the influence can be eliminated, and it becomes possible to radiate illumination light with uniform brightness over the entire light emitting surface.

  In the illumination device according to the present invention, the calculation result includes a difference between a maximum value and a minimum value of the plurality of brightnesses.

  With this configuration, the difference between the maximum and minimum brightness values of the light emitting module detected by the brightness detector is calculated, and the current applied to the light emitting module is controlled based on the calculated result. Therefore, even if there is a singular point of luminance, the influence can be eliminated, and illumination light can be emitted with uniform brightness over the entire light emitting surface.

  Further, the present invention includes the lighting device, wherein the lighting circuit controls the current applied to the light emitting module to stop when the calculation result becomes a predetermined value or more. .

  With this configuration, when the difference in brightness of the light emitting module detected by the brightness detection unit exceeds a predetermined value, the user can control the current applied to the light emitting module to stop and turn off. The lifetime of the light emitting module can be easily determined, and the maintainability of the lighting device is improved.

  In the lighting device according to the present invention, the lighting circuit may control the current to be applied so that the light emitting module blinks when the calculation result is equal to or greater than a predetermined value. Including.

  With this configuration, when the brightness difference of the light emitting module detected by the brightness detecting unit exceeds a predetermined value, the user can control the life of the light emitting module by controlling the light emission of the light emitting module to blink. This can be easily determined, and the maintainability of the lighting device is improved.

  Further, the present invention includes the lighting device in which the lighting circuit outputs a signal to the outside when the difference in brightness becomes a predetermined value or more.

  With this configuration, when the difference in current applied to a plurality of light emitting modules exceeds a predetermined value, the user can easily determine the life of the light emitting module by outputting a signal to the outside, Maintainability in the apparatus and the lighting system is improved.

  Furthermore, the present invention includes an illumination device as described above, wherein the planar light emitting element is an organic electroluminescence light emitting element.

  With this configuration, it is possible to provide an organic electroluminescence lighting device that can be lit at a predetermined brightness without being affected by individual variation and aging, and that can uniformly emit illumination light from the entire light emitting surface.

  According to the present invention, it is possible to provide an illuminating device capable of uniformly lighting the entire light emitting surface with a predetermined brightness without being affected by individual variation or aging.

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

(Embodiment 1)
1A and 1B are schematic views showing a basic configuration of a lighting apparatus according to Embodiment 1 of the present invention, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view.

  In FIG. 1, the illuminating device 1 in this embodiment is the structure which has the organic EL light emitting module 10 and the brightness detection part 20 for detecting the brightness of the organic EL light emitting module 10. In FIG.

  As shown in FIG. 1B, the organic EL light emitting module 10 includes a substrate 11, an anode electrode layer 12, an organic EL light emitting layer 13, a cathode electrode layer 14, and a sealing layer 15.

  The substrate 11 is made of glass or the like that is transparent to the light generated in the organic EL light emitting layer 13, and the anode electrode layer 12 is an ITO (Indium Tin Oxide) vapor deposition for constituting the anode. It is formed from a film and has translucency with respect to the light generated in the organic EL light emitting layer 13.

  The organic EL light emitting layer 13 is formed by forming a low molecular weight or high molecular weight organic fluorescent material into a thin film, and a portion sandwiched between the anode electrode layer 12 and the cathode electrode layer 14 is a light emitting region.

  The cathode electrode layer 14 is a conductive thin film that serves as a cathode, and is formed of, for example, an ITO vapor-deposited film and is translucent to light generated in the organic EL light emitting layer 13. Further, the sealing layer 15 is formed of a metal thin film such as aluminum or tungsten for protecting the layers below the cathode electrode layer 14 from the outside, and has a minute opening 16 at an arbitrary position, for example, the central portion. It is configured.

  The anode electrode layer 12 and the cathode electrode layer 14 are connected to a lighting circuit 30 shown in FIG. 4 to be described later via an electrode terminal (not shown). By applying a voltage between both electrode layers, the organic EL light emitting layer 13 emits light, The illumination light P1 is emitted to the outside through the substrate 11, and the detection light P2 is leaked to the outside through the cathode electrode layer 14 and the opening 16 formed in the sealing layer 15.

  The brightness detection unit 20 is disposed close to and opposed to the opening 16, and detects the light amount of the detection light P <b> 2 emitted from the opening 16 by an optical sensor such as a photodiode, whereby the organic EL light emitting module 10. A brightness detection signal corresponding to the brightness is output.

  FIG. 2 is a diagram illustrating a schematic configuration of the brightness detection unit 20. In FIG. 2, when the photodiode PD generates a current corresponding to the brightness of the detection light P2, a brightness detection signal having a voltage proportional to the current value is generated by a current-voltage conversion circuit including a resistor R1 and an operational amplifier OP1. Output.

  This brightness detection signal is a voltage signal proportional to the brightness of the organic EL light emitting module 10, for example, as shown in FIG.

  FIG. 4 is a diagram showing a schematic configuration of a lighting circuit for lighting the lighting device 1 with a predetermined brightness.

  In FIG. 4, the lighting circuit 30 is detected as a voltage value across the resistor R <b> 2 and the DC power source E <b> 1, the switching transistor Q <b> 1 that controls the current Ila supplied to the organic EL light emitting module 10, and the resistor R <b> 2. The configuration includes an operational amplifier OP2 that calculates a difference between the current and the current reference value, and a current reference value adjustment unit 31 that adjusts a current reference value for lighting the organic EL light emitting module 10 with a predetermined brightness.

  Next, the operation of the lighting circuit 30 for lighting the organic EL light emitting module 10 with a predetermined brightness in the lighting device 1 of the present embodiment configured as described above will be described. FIG. 5 is a flowchart for explaining the operation of the lighting circuit 30.

  First, in step S101, a predetermined current reference value is output from the current reference value adjustment unit 31 to the operational amplifier OP2 as an initial value, and the current Ila is caused to flow through the organic EL light emitting module 10 by the switching transistor Q1, so that the organic EL light emitting module 10 is predetermined. Light up at a brightness of.

  The initial value of the current reference value is determined in consideration of the lifetime of the organic EL light emitting module 10. For example, when it is predicted that the brightness at the end of the lifetime will decrease by 30% compared to the time of starting lighting, a current that is 30% lower than the rated current is set as the initial value of the current reference value. Thus, while the lighting time is short, the current supplied to the organic EL light emitting module 10 can be reduced by 30%, and a constant brightness can be maintained over the entire lifetime.

  On the other hand, the reference value of the brightness of the organic EL light emitting module 10 is measured or measured as the level of the brightness detection signal output from the brightness detection unit 20 when the lighting device 1 can obtain a predetermined brightness. It is given as a constant determined by calculation.

  In step S <b> 102, the brightness of the organic EL light emitting module 10 that emits light by the current Ila is detected by the brightness detection unit 20, and the obtained brightness detection signal is output to the current reference value adjustment unit 31.

  The current reference value adjustment unit 31 determines whether or not the organic EL light emitting module 10 emits light with a predetermined brightness based on the brightness detection signal (step S103), and emits light brighter than the predetermined brightness. If it is determined that the reference value of the current Ila flowing through the organic EL light emitting module 10 is lowered (step S104), and if it is determined that light is emitted darker than the predetermined brightness, the reference value of the current Ila is adjusted to be increased ( Step S105).

  The reference value of the current Ila adjusted in this way is output to the operational amplifier OP2 (step S106), and is obtained by differential amplification with the voltage across the resistor R2 generated by the current that actually flows through the organic EL light emitting module 10. Is applied to the base of the switching transistor Q1. Thereby, the switching transistor Q1 controls the current Ila supplied to the organic EL light emitting module 10 to be equal to the reference value (step S107).

  Thereafter, the steps S102 to S107 are repeated while the lighting device 1 is turned on.

  Thereby, the organic EL light emitting module 10 can emit light with a predetermined brightness. In addition, even when the light emission efficiency of the organic EL light emitting module 10 changes due to secular change, the same brightness as the beginning of lighting can be maintained until the end of the life by controlling the lighting based on the brightness reference value in this way. it can.

  Further, when a plurality of such lighting devices 1 are arranged and lit up in the same room, uniform brightness can be obtained in all the lighting devices 1 by making the brightness reference value common. In particular, in the case of a lighting fixture in which a plurality of lighting devices 1 are arranged, it is possible to emit light with uniform brightness over the entire surface.

  In the above description, the brightness of the organic EL light emitting module 10 is detected by one brightness detection unit 20, but a plurality of openings 16 are provided in the sealing layer 15 as shown in FIG. A plurality of brightness detectors 20 may be arranged in proximity to or opposite to each other. Thereby, it is possible to detect the brightness with higher accuracy.

  FIG. 6 is an example in which the brightness of four locations of the lighting device 1 is detected. Normally, the brightness of the four places is almost uniform at the beginning of lighting of the lighting device 1, and the variation is within a predetermined range. Therefore, the current applied to the light emitting module 10 is controlled so that uniquely determined values such as the average value, maximum value, and minimum value of the four brightness detection values coincide with the brightness reference value.

  In the illuminating device 1, since the organic EL light emitting module 10 is formed in a planar shape, current concentrates on a part of the organic EL light emitting layer 13 due to some abnormality, and the brightness of the part increases or deteriorates. Depending on the condition, it may become dark. Also, the brightness may partially change due to secular change.

  In such a case, since the difference between the plurality of brightness detection signals exceeds a predetermined range, this is detected and the current applied to the light emitting module 10 is set to a value different from normal, for example, the emission is stopped, Alternatively, the switching transistor Q1 is controlled so as to blink. As a result, the user can determine the abnormality or life of the lighting device 1 and the maintainability is improved.

  Furthermore, when a difference between a plurality of brightness detection signals exceeds a predetermined value, a signal is output to the outside to turn on an external lighting device, or as a trigger for notifying a warning or the like Also good. This facilitates maintenance and management in an illumination system or the like configured by combining a large number of illumination devices.

  As described above, according to such a lighting apparatus according to Embodiment 1 of the present invention, the sealing layer constituting the organic EL light emitting module has a minute opening and is close to and faces the opening. To arrange a brightness detector. Then, the light emitted from the organic EL light emitting module leaking from the opening is detected and a brightness detection signal is output, and the current of the organic EL light emitting module is controlled by adjusting the reference value of the current applied to the organic EL light emitting module. . Thereby, it is possible to provide an illuminating device that is lit at a predetermined brightness without being affected by individual variation or aging.

(Embodiment 2)
7A and 7B are schematic views showing a basic configuration of a lighting apparatus according to Embodiment 2 of the present invention, where FIG. 7A is a plan view and FIG. 7B is a cross-sectional view. In addition, about the part which is common in the illuminating device in Embodiment 1 of this invention shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In FIG. 7, the illuminating device 2 in this Embodiment is the structure which has the organic EL light emitting module 40 and the brightness detection part 20 for detecting the brightness of the organic EL light emitting module 40. In FIG.

  As shown in FIG. 7B, the organic EL light emitting module 40 includes a substrate 11, an anode electrode layer 12, an organic EL light emitting layer 13, a cathode electrode layer 44, and a sealing layer 15.

  In common with the sealing layer 15, the cathode electrode layer 44 has a minute opening 16 at an arbitrary position, for example, at the center.

  The anode electrode layer 12 and the cathode electrode layer 44 are connected to the lighting circuit 30 shown in FIG. 4 through a terminal (not shown), and the organic EL light emitting layer 13 emits light by applying a voltage between the two electrode layers. Illumination light P <b> 1 is radiated to the outside through 11. At this time, a voltage is not applied to the organic EL light emitting layer 13 immediately below the opening 16 of the cathode electrode layer 44, so that no light is emitted. However, the opening 16 has a very small size and affects the entire illumination light P1. There is nothing.

  On the other hand, in the opening portion 16, there is leakage light P <b> 3 from the periphery immediately below the opening portion 16 of the organic EL light emitting layer 13, and the brightness detection unit 20 disposed close to and opposite to the opening portion 16 has this leakage light. By detecting P3, a brightness detection signal corresponding to the brightness of the organic EL light emitting module 40 is output.

  The brightness detection signal is input to the lighting circuit 30 shown in FIG. 4 in the first embodiment, and controls the current applied to the organic EL light emitting module 40 according to the procedure of the flowchart shown in FIG. As a result, the organic EL light emitting module 40 can emit light with a predetermined brightness, and even when the light emission efficiency changes due to secular change, the same brightness as the initial lighting is obtained by turning on the light based on the brightness reference value. Can be maintained.

  As described above, according to the lighting device according to the second embodiment of the present invention, the cathode electrode layer and the sealing layer constituting the organic EL light emitting module have a small opening in common, and the opening A brightness detection unit is arranged close to and opposite to the unit. Then, the light emission of the organic EL light emitting module leaking from the opening is detected and a brightness detection signal is output, and the current is controlled by adjusting the reference value of the current applied to the organic EL light emitting module. As a result, it is possible to provide an illuminating device that is lit at a predetermined brightness without depending on individual variations and secular changes.

  The cathode electrode layer 44 and the sealing layer 15 may be formed in common with a metal thin film such as aluminum. Thereby, the manufacturing process of the organic EL light emitting module is simplified, and the price of the lighting device can be reduced.

(Embodiment 3)
FIG. 8 is a perspective view showing a schematic configuration of the illumination apparatus according to Embodiment 3 of the present invention. In addition, about the same structure as the illuminating device in Embodiment 1 of this invention shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In FIG. 8, the illumination device 3 according to the present embodiment includes an organic EL light emitting module 50, four brightness detection units 20 (not shown), and a lighting circuit for lighting the organic EL light emitting module 50 with a predetermined brightness. 60.

  The organic EL light emitting module 50 is a planar light emitting module having an anode terminal 57 and a cathode terminal 58 at both ends, and a light emitting surface 59 by a direct current applied from the lighting circuit 60 via the anode terminal 57 and the cathode terminal 58. Illumination light is emitted from.

  The lighting circuit 60 includes a brightness calculation unit 61, a current control unit 62, and a DC power source 63.

  The brightness calculation unit 61 calculates the brightness detection signals output from the plurality of brightness detection units 20, adjusts the current reference value for lighting the organic EL light emitting module 50 with a predetermined brightness, The control value of the current applied to the organic EL light emitting module 50 is set. The current control unit 62 controls the current applied to the organic EL light emitting module 50 based on the set current control value.

  The DC power source 63 is configured by an AC / DC converter that converts AC power supplied from a commercial AC power source into DC power having a predetermined voltage value. Further, a battery or a combination of a battery and an AC / DC converter may be used.

  The lighting circuit 60 and the brightness detection unit 20 (not shown) configured as described above are mounted on a mounting board. FIG. 9 is a perspective view showing an appearance of the illumination device 3 configured by integrating the organic EL light emitting module 50 and the mounting substrate 70.

  FIG. 10 is an exploded perspective view showing the internal configuration of the illumination device 3 shown in FIG.

  In FIG. 10, the illumination device 3 includes an organic EL light emitting module 50 and a mounting substrate 70.

  The organic EL light emitting module 50 emits light when energized in the thickness direction with a glass substrate 51 made of a light-transmitting insulating material, an anode electrode layer 52 made of a light-transmitting conductive material such as ITO. An organic EL light emitting layer 53, a cathode electrode layer 54 made of a metal thin film and interposed between the organic EL light emitting layer 53 and the anode electrode layer 52 in the thickness direction, and a glass made of a translucent insulating material. A sealing layer 55 such as the like is sequentially laminated.

  An anode terminal 57 and a cathode terminal 58 (not shown) are formed on the glass substrate 51, and are connected to the anode electrode layer 52 and the cathode electrode layer 54 through ITO, respectively. The connection to the anode terminal 57 and the cathode terminal 58 is not limited to ITO, and a metal thin film such as aluminum may be formed by vapor deposition, plating, sputtering, or the like.

  The cathode electrode layer 54 is formed using a metal thin film such as aluminum in order to improve the luminance in the irradiation direction of the organic EL light emitting layer 53, and has a plurality of minute openings 56 (four in FIG. 10). Provided. The opening 56 is sealed by the sealing layer 55, and light leaking from the organic EL light emitting layer 53 when light is emitted is disposed facing and close to the brightness detecting unit 20 shown in FIG. To the photodiode PD. Thereby, the brightness can be detected without affecting the light on the illumination side of the organic EL light emitting layer 53.

  On the mounting substrate 70, the same number of brightness detection units 20 as the openings 56, the brightness calculation unit 61 and the current control unit 62 of the lighting circuit 60 described in FIG. In the present embodiment, four brightness detection units 20 are arranged. However, the number is not limited, and the number required to detect the brightness of a necessary portion of the organic EL light-emitting layer 53 is not limited. If it is.

  Next, an operation example of the illumination device 3 according to this embodiment configured as described above will be described.

  FIG. 10 is a diagram illustrating a transition of the brightness detected by the brightness detection unit 20 with the lighting time. In the figure, La to Ld indicate the respective brightness detection values detected by the four brightness detection units 20. The horizontal axis indicates the lighting time. For example, it is a long range time corresponding to the life of the lighting device 3 at full scale.

  Referring to FIG. 10, the brightness detection values La to Ld have remained at a substantially constant same level for a while since the start of lighting, but La and Lb gradually increase and Lc decreases with the passage of time. The trend is being followed.

  As described above, since the increase and decrease in the brightness detection value occur in one lighting device 3, it is estimated that the luminance variation occurs in the light emitting surface. Possible causes include a non-uniform temperature distribution on the light emitting surface and deterioration of the organic EL light emitting material. However, the variation in luminance is due to the fact that the current flowing through the organic EL light emitting layer 53 is non-uniform. In particular, in the portion that emits light brightly, more current flows than usual. Presumed.

  The portion of the organic EL light emitting layer 53 that emits light brightly deteriorates with time, and there is a risk of shortening the lifetime. Therefore, in the lighting device 3 of the present embodiment, the brightness calculation unit 61 calculates the difference between the maximum value and the minimum value of the brightness detection values La to Ld detected by the four brightness detection units 20, respectively. When the predetermined value l is exceeded, the setting of the current passed through the organic EL light emitting layer 53 is changed, and the current control unit 62 suppresses the maximum value Imax of the current passed through the organic EL light emitting layer 53 according to the changed current setting. To control.

  Thereby, it can suppress that the electric current to the part to which the brightness rose further increases, and it becomes possible to prevent that the lifetime of the illuminating device 3 is shortened.

  FIG. 11 shows an example in which control is performed to suppress the maximum current value Imax by 30% when the difference between the maximum value and the minimum value of the brightness detection values La to Ld exceeds a predetermined value l. However, for example, as shown in FIG. 12, the maximum current value Imax may be controlled to change linearly in accordance with the difference between the maximum value and the minimum value.

  Further, in the present embodiment, the suppression of the maximum value Imax of the current flowing through the organic EL light emitting layer 53 is controlled based on the difference between the maximum value and the minimum value of the brightness detection values La to Ld. For example, the control may be performed based on the difference between the maximum value and the average value, the absolute value of the maximum value, or the like.

  In FIG. 13, the brightness calculator 61 calculates the difference between the maximum and minimum brightness detection values La to Ld detected by the four brightness detectors 20, respectively, and this value exceeds a predetermined value m. In some cases, a signal indicating that the luminance variation exceeds the limit is output to the outside.

  Vext in FIG. 13 is 0V in a normal state, and when the difference between the maximum value and the minimum value of the detection values La to Ld exceeds a predetermined value m, it becomes an H level of 5V. By receiving this Vext by an external circuit, it is possible to take measures such as stopping AC power to the lighting device 3 or issuing a warning message. Thereby, the maintenance of the illuminating device 3 becomes easy.

  As described above, according to the illumination device 3 according to Embodiment 3 of the present invention, a plurality of minute openings 56 are provided in the cathode electrode layer 54 of the metal thin film that constitutes the organic EL light emitting module 50. Then, the same number of brightness detection units 20 are arranged close to and opposed to the opening 56. In addition to the brightness detection unit 20, a brightness calculation unit 61 and a current control unit 62 that constitute the lighting circuit 60, and a power supply unit 63 are mounted on the mounting substrate 70, and the organic EL light emitting layer 53 leaks from the opening 56. Are detected by a plurality of brightness detection units 20, and each brightness detection value is calculated by a brightness calculation unit 61, and a current reference value for lighting the organic EL light emitting module 50 at a predetermined brightness is obtained. By adjusting, the control value of the current applied to the organic EL light emitting module 50 is set. The current control unit 62 controls the current applied to the organic EL light emitting module 50 based on the set current control value.

  Thereby, the lighting device 3 can be turned on with a predetermined brightness, and the lifetime of the lighting device 3 can be prevented from being shortened due to a partial brightness variation of the organic EL light emitting layer 53.

  The lighting device according to the present invention has an effect of being able to light the entire light emitting surface uniformly with a predetermined brightness without being affected by individual variation and secular change, and is useful for lighting fixtures, display devices, and the like. is there.

Schematic which shows the basic composition of the illuminating device in Embodiment 1 of this invention (a) Top view (b) Sectional drawing The figure which shows schematic structure of the brightness detection part in Embodiment 1 of this invention. The figure which shows the relationship between the brightness of the illuminating device in Embodiment 1 of this invention, and a brightness detection signal. The figure which shows schematic structure of the lighting circuit of the illuminating device in Embodiment 1 of this invention. The flowchart for demonstrating operation | movement of the lighting circuit of the illuminating device in Embodiment 1 of this invention. The perspective view which shows schematic structure of the light emitting module of the illuminating device in Embodiment 1 of this invention. Schematic which shows the basic composition of the illuminating device in Embodiment 2 of this invention (a) Top view (b) Sectional drawing The perspective view which shows schematic structure of the illuminating device in Embodiment 3 of this invention. The perspective view which shows the external appearance of the illuminating device in Embodiment 3 of this invention. The disassembled perspective view which shows the internal structure of the illuminating device in Embodiment 3 of this invention. The figure which shows the time transition of the brightness which the illuminating device in Embodiment 3 of this invention detected. The figure which shows the example controlled based on the difference of the maximum value and minimum value of the brightness which detected the electric current applied to the light emitting module of the illuminating device in Embodiment 3 of this invention. The figure which shows the example which outputs a signal outside according to the brightness which the illuminating device in Embodiment 3 of this invention detected. The figure which shows schematic structure of the lighting circuit in the conventional illuminating device. The figure which shows the relationship between the electric current of an organic EL element and the brightness in the conventional illuminating device.

Explanation of symbols

1, 2, 3 Illumination device 10, 40, 50 Organic EL light emitting module 11, 51 Glass substrate 12, 52 Anode electrode layer 13, 53 Organic EL light emitting layer 14, 54 Cathode electrode layer 15, 55 Sealing layer 20 Brightness detection Unit 30, 60 lighting circuit 31 current reference value adjustment unit 61 brightness calculation unit 62 current control unit

Claims (5)

A lighting device that emits light by applying a current from a lighting circuit to a light emitting module configured by interposing a planar light emitting element between opposing electrodes,
A light-shielding body having an opening is laminated on the electrode located on the non-irradiation side of light generated from the planar light emitting element,
A brightness detection unit that is disposed close to and opposed to the opening and directly detects light of the planar light emitting element that leaks through the opening,
The lighting circuit is
Based on the brightness detected by the brightness detector,
An illumination device that lowers the applied current if the light emitting module is lit brighter than a predetermined brightness, and increases the applied current if the light emitting module is lit darker than the predetermined brightness. A lighting device that emits light by applying a current from a lighting circuit to a light emitting module configured by interposing a planar light emitting element between opposing electrodes,
The electrode located on the non-irradiation side of the light generated from the planar light emitting element has an opening,
A brightness detection unit that is disposed close to and opposed to the opening and directly detects light of the planar light emitting element that leaks through the opening,
The lighting circuit is
Based on the brightness detected by the brightness detector,
An illumination device that lowers the applied current if the light emitting module is lit brighter than a predetermined brightness, and increases the applied current if the light emitting module is lit darker than the predetermined brightness. The lighting device according to claim 1 or 2,
A plurality of the openings,
The same number of the brightness detectors as the openings,
The lighting circuit is
Calculate a plurality of brightness detected by the brightness detection unit, based on the calculation result,
A lighting device for controlling the current applied to the light emitting module. The lighting device according to claim 3,
The calculation result is
An illumination device that is an average value of the plurality of brightnesses. The lighting device according to claim 3,
The calculation result is
An illumination device that is a difference between a maximum value and a minimum value of the plurality of brightnesses.

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