Light emitting device, display device, and method for inspecting light emitting device

Abstract

To detect an abnormality in a light emitting device having a plurality of light emitting elements by a method different from the conventional method.SOLUTION: A light emitting device (10P) includes a plurality of light emitting units (UN_1 to UN_12) respectively composed of a plurality of light emitting elements connected in series and in a forward direction. The plurality of light emitting units includes a first light emitting unit (e.g., UN_1) and a second light emitting unit (e.g., UN_2) corresponding to the first light emitting unit. A first anode side node (e.g., AN_1) serving as an anode side node of the first light emitting unit is connected to a second anode side node (e.g., AN_2) serving as the anode side node of the second light emitting unit. A first cathode side node (e.g., CA_1) serving as the cathode side node of the first light emitting unit is connected to a second cathode side node (e.g., CA_2) serving as the cathode side node of the second light emitting unit. The light emitting device (10P) further includes a switch (e.g., SW1) located between the first cathode side node and the second anode side node.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The following disclosure relates to a light emitting device having a plurality of light emitting elements. [Background technology]

[0002] Various technologies have been proposed for light-emitting devices that have light-emitting elements such as LEDs (Light Emitting Diodes) as light sources. For example, Patent Document 1 listed below discloses a technology aimed at detecting a connection error in a cable that connects an LED board and an LED drive board in an LED lighting device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-99629 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one embodiment of the present disclosure is to detect an abnormality in a light-emitting device having a plurality of light-emitting elements by a method different from that of the conventional method. [Means for solving the problem]

[0005] In order to solve the above problems, a light-emitting element according to one embodiment of the present disclosure includes a plurality of light-emitting units, each of which is composed of a plurality of light-emitting elements connected in series and in a forward direction, and the plurality of light-emitting units include a first light-emitting unit and a second light-emitting unit corresponding to the first light-emitting unit, a first anode-side node which is an anode-side node of the first light-emitting unit is connected to a second anode-side node which is an anode-side node of the second light-emitting unit, and a first cathode-side node which is a cathode-side node of the first light-emitting unit is connected to a second cathode-side node which is a cathode-side node of the second light-emitting unit, and the light-emitting device further includes a switch located between the first cathode-side node and the second anode-side node.

[0006] In addition, in a method for inspecting a light emitting device according to an aspect of the present disclosure, the light emitting device comprises a plurality of light emitting units, each of which is composed of a plurality of light emitting elements connected in series in a forward direction, the plurality of light emitting units including a first light emitting unit and a second light emitting unit corresponding to the first light emitting unit, a first anode side node which is an anode side node of the first light emitting unit is connected to a second anode side node which is an anode side node of the second light emitting unit, a first cathode side node which is a cathode side node of the first light emitting unit is connected to a second cathode side node which is a cathode side node of the second light emitting unit, the light emitting device further comprises a switch located between the first cathode side node and the second anode side node, The inspection method includes a step of connecting the first cathode side node and the second anode side node by turning on the switch when starting an inspection mode to inspect whether or not there are any abnormalities in the first light-emitting unit and the second light-emitting unit in the light-emitting device. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, it is possible to detect an abnormality in a light-emitting device having a plurality of light-emitting elements by a method different from the conventional method. [Brief explanation of the drawings]

[0008] [Figure 1] 1 shows a configuration example of a display device according to a reference embodiment. [Figure 2] 10 shows examples of signals output from each of a plurality of signal terminals in the reference embodiment. [Figure 3] 10 shows another example of the configuration of the display device according to the reference embodiment. [Figure 4] 1 shows an example of the configuration of a display device according to a first embodiment. [Figure 5] 3 shows examples of signals output from each of a plurality of signal terminals in the first embodiment. [Figure 6] FIG. 4 is a diagram illustrating a first operation example of the display device of the first embodiment. [Figure 7] FIG. 10 is a diagram illustrating a second operation example of the display device of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Reference form] Before describing the display device 1P of the first embodiment, a reference embodiment will be described. For convenience of explanation, components having the same functions as those described in the reference embodiment will be denoted by the same reference numerals in the following embodiments, and their descriptions will not be repeated. For simplicity, descriptions of matters similar to those in known technologies will also be omitted as appropriate.

[0010] Unless otherwise specified, all components and numerical values ​​described in this specification are merely examples. Therefore, for example, unless otherwise specified, the number, positional relationship, and connection relationship of each component are not limited to the examples in each figure. In this specification, unless otherwise specified, the word "connected" means "electrically connected."

[0011] (Example of a configuration of a display device in a reference embodiment) Fig. 1 shows an example of the configuration of a display device according to a reference embodiment. The display device in Fig. 1 is referred to as display device 1. Fig. 2 shows an example of signals output from each of a plurality of signal terminals (described later) in display device 1.

[0012] First, refer to Fig. 1. The display device 1 includes a light emitting device 10 and a control device 20. The light emitting device 10 has a plurality of light emitting elements. In this specification, the case where the light emitting elements are LEDs will be exemplified.

[0013] The control device 20 comprehensively controls each part of the display device 1. In this specification, the case where the control device 20 controls the light-emitting device 10 will be described. However, the control device 20 may also control components (not shown) of the display device 1. For example, if the display device 1 is a liquid crystal display device, the display device 1 has a liquid crystal panel. In this case, the control device 20 may control the liquid crystal panel.

[0014] As an example, consider a case where the display device 1 is a liquid crystal display device. In this case, the light emitting device 10 is, for example, a backlight of the display device 1. The light emitting element in the light emitting device 10 is, for example, a white LED that emits white light. In the display device 1, the white light is emitted as illumination light from the light emitting device 10 toward the liquid crystal panel. Therefore, by controlling the light emitting device 10 with the control device 20, the brightness of the emitted light can be controlled.

[0015] 1 includes six light-emitting units UN_1 to UN_6 mounted on a circuit board 110. In this specification, a plurality of light-emitting units (e.g., six light-emitting units UN_1 to UN_6) may be collectively referred to as a light-emitting unit UN.

[0016] In the example of Fig. 1, the plurality of light-emitting units UN are connected in parallel with one another. Each light-emitting unit UN is composed of a plurality of light-emitting elements connected in series in the forward direction. In the example of Fig. 1, each light-emitting unit UN is composed of six light-emitting elements.

[0017] In this specification, the i-th light-emitting unit among the plurality of light-emitting units UN is referred to as light-emitting unit UN_i. i is any natural number satisfying 1≦i≦N. N is the total number of light-emitting units in the light-emitting device. In the example of FIG. 1, N=6.

[0018] In this specification, light-emitting elements belonging to a light-emitting unit UN_i are collectively referred to as light-emitting element Di. The j-th light-emitting element among the plurality of Di belonging to the light-emitting unit UN_i is referred to as light-emitting element Di_j. M is the number of light-emitting elements belonging to one light-emitting unit UN in the light-emitting device. In the example of FIG. 1, M=6. Therefore, the light-emitting device 10 in the example of FIG. 1 has a total of 36 light-emitting elements.

[0019] 1 includes a driving unit 120 that drives each of a plurality of light-emitting units UN. In this specification, for any i, the anode of the light-emitting element Di_1 in the light-emitting unit UN_i is connected to one signal terminal of the driving unit 120, and the cathode of the light-emitting element Di_M in the light-emitting unit UN_i is connected to another signal terminal of the driving unit 120.

[0020] Additionally, as is clear from the above description, in the light emitting unit UN_i, for any j in the range of 1≦j≦M−1, the cathode of the light emitting element Di_j is connected to the anode of the light emitting element Di_(j+1).

[0021] Therefore, the light-emitting unit UN_i has an anode-side node AN_i and a cathode-side node CA_i. In this specification, the anode-side node AN_i refers to a node within the light-emitting unit UN_i that has the same potential as the anode of the light-emitting element Di_1. Furthermore, the cathode-side node CA_i refers to a node within the light-emitting unit UN_i that has the same potential as the cathode of the light-emitting element Di_M.

[0022] The driving unit 120 receives commands from the control device 20 and drives each of the plurality of light-emitting units UN. In this specification, signals supplied from the driving unit 120 to the anode-side nodes are collectively referred to as anode signals. The anode signals A1 to A2 shown in FIG. 2 are each individual anode signals. Furthermore, signals supplied from the driving unit 120 to the cathode-side nodes are collectively referred to as cathode signals. The cathode signals K1 to K6 shown in FIG. 2 are each individual cathode signals.

[0023] 1, the driving unit 120 has eight signal terminals T1 to T8. The signal terminal T1 is connected to each of the anode-side nodes AN_4 to AN_6. This allows the driving unit 120 to supply an anode signal A2 to each of the light-emitting units UN_4 to UN_6 via the signal terminal T1.

[0024] The signal terminal T2 is connected to each of the anode-side nodes AN_1 to AN_3, so that the anode signal A1 can be supplied from the driving unit 120 to each of the light-emitting units UN_1 to UN_3 via the signal terminal T2.

[0025] As described above, in the example of Fig. 1, one signal terminal of the drive unit 120 is connected to multiple anode-side nodes. Specifically, in the example of Fig. 1, one signal terminal of the drive unit 120 is connected to three anode-side nodes.

[0026] 1, one signal terminal of the driving unit 120 is connected to one cathode node. For example, the signal terminal T3 is connected to the cathode node CA_1. This allows the driving unit 120 to supply the cathode signal K1 to the light-emitting unit UN_1 through the signal terminal T3.

[0027] Similarly, signal terminal T4 is connected to cathode side node CA_2, signal terminal T5 is connected to cathode side node CA_3, signal terminal T6 is connected to cathode side node CA_4, signal terminal T7 is connected to cathode side node CA_5, and signal terminal T8 is connected to cathode side node CA_6.

[0028] This allows a cathode signal K2 to be supplied to light-emitting unit UN_2 through signal terminal T4, a cathode signal K3 to light-emitting unit UN_3 through signal terminal T5, a cathode signal K4 to light-emitting unit UN_4 through signal terminal T6, a cathode signal K5 to light-emitting unit UN_5 through signal terminal T7, and a cathode signal K6 to light-emitting unit UN_6 through signal terminal T8.

[0029] Incidentally, if an abnormality (e.g., deterioration) occurs in a light-emitting element constituting the light-emitting unit UN, for example, when the light-emitting element is driven at a low current, the light-emitting element may fail to emit light (e.g., not emit light). Therefore, if an abnormality occurs in a light-emitting element constituting the light-emitting unit UN, there is a risk that the display quality of the display device 1 may be reduced.

[0030] Even if all of the light-emitting elements of the light-emitting device 10 are confirmed to be normal when the light-emitting device 10 is manufactured, some abnormality may occur in some of the light-emitting elements after the light-emitting device 10 is incorporated into the display device 1. For this reason, it is desirable to detect an abnormality in the light-emitting unit UN of the light-emitting device 10 without removing the light-emitting device 10 from the display device 1.

[0031] Therefore, the display device 1 is configured to operate the light emitting device 10 in a mode (hereinafter referred to as an "inspection mode") for inspecting whether or not there is an abnormality in the light emitting unit UN of the light emitting device 10. For example, the control device 20 may start the inspection mode of the light emitting device 10 upon receiving a predetermined input operation from the user of the display device 1.

[0032] 1, in the test mode of the light-emitting device 10, the control device 20 controls the drive unit 120 to supply an anode signal of a predetermined signal value and a cathode signal of a predetermined signal value to one light-emitting unit UN. As a result, a test current flows through the light-emitting unit UN. In this specification, the current value of the test current is set to be smaller than the current value of the current flowing through the light-emitting unit UN in the normal display mode of the display device 1.

[0033] As an example, a case where the light-emitting unit UN_1 is inspected will be described. In this case, an anode signal A1 having a predetermined signal value is supplied to the anode-side node AN_1 through the signal terminal T2, and a cathode signal K1 having a predetermined signal value is supplied to the cathode-side node CA_1 through the signal terminal T3. As a result, an inspection current flows through the light-emitting unit UN_1.

[0034] Therefore, a forward voltage Vf_1 corresponding to the test current is generated in the light-emitting unit UN_1. The forward voltage Vf_1 in the light-emitting unit UN_1 is equal to the sum of the forward voltages of the light-emitting elements D1_1 to D1_6. When an abnormality occurs in any of the light-emitting elements D1_1 to D1_6, Vf_1 is considered to be lower than when all of the light-emitting elements D1_1 to D1_6 are healthy. Therefore, in the test mode of the light-emitting device 10, it is possible to determine whether or not an abnormality occurs in the light-emitting unit UN_1 based on Vf_1 in the light-emitting unit UN_1.

[0035] Therefore, the light-emitting device 10 may have a voltage sensor (not shown) that measures the potential difference between two signal terminals of the drive unit 120 corresponding to a certain light-emitting unit UN. As an example, consider a case where a voltage sensor is provided that detects the potential difference between signal terminals T2 and T3 corresponding to light-emitting unit UN_1. In this case, the control device 20 acquires the detected value of the potential difference detected by the voltage sensor in the inspection mode as Vf_1 in the inspection mode. Then, the control device 20 determines whether or not an abnormality has occurred in the light-emitting unit UN_1 based on Vf_1.

[0036] (Another configuration example of the display device in the reference embodiment) Fig. 3 shows another example of the configuration of a display device according to the reference embodiment. The display device in Fig. 3 is referred to as display device 1A. In display device 1A as well, the signals output from each of signal terminals T1 to T8 are assumed to be the same as those shown in Fig. 2 above.

[0037] The display device 1A has a light emitting device 10A instead of the light emitting device 10. Unlike the example in Fig. 1, Fig. 3 illustrates a case where N=12. Therefore, the light emitting device 10A in Fig. 3 has a total of 72 light emitting elements.

[0038] The light emitting device 10A in the example of Fig. 3 includes 12 light emitting units UN_1 to UN_12, and therefore 12 anode side nodes AN_1 to AN_12 and 12 cathode side nodes CA_1 to CA12 are shown in Fig. 3.

[0039] As such, the value of N in the example of Fig. 3 is twice the value of N in the example of Fig. 1. On the other hand, the driving unit 120 in the example of Fig. 3 is equivalent to that in the example of Fig. 1. For this reason, in the example of Fig. 3, the connection relationship between the driving unit 120 and each of the plurality of light-emitting units UN is different from that in the example of Fig. 1.

[0040] Specifically, in the example of Fig. 3, one signal terminal of the drive unit 120 is connected to six anode-side nodes. In the example of Fig. 3, signal terminal T1 is connected to each of anode-side nodes AN_7 to AN_12. And signal terminal T2 is connected to each of anode-side nodes AN_1 to AN_6.

[0041] 3, when an anode signal A2 is output from the signal terminal T1, the anode signal A2 is supplied to each of the light-emitting units UN_7 to UN_12. When an anode signal A1 is output from the signal terminal T2, the anode signal A1 is supplied to each of the light-emitting units UN_1 to UN_6.

[0042] In addition, in the example of Fig. 3, one signal terminal of the driving unit 120 is connected to two cathode-side nodes. In the example of Fig. 3, the signal terminal T3 is connected to the cathode-side nodes CA_1 and CA_2. Therefore, in the example of Fig. 3, unlike the example of Fig. 1, the cathode-side node CA_1 is connected to the cathode-side node CA_2. Therefore, in the example of Fig. 3, when a cathode signal K1 is output from the signal terminal T3, the cathode signal K1 is supplied to each of the light-emitting units UN_1 and UN_2.

[0043] The signal terminal T4 is connected to the cathode-side nodes CA_3 to CA_4. Therefore, in the example of Fig. 3, unlike the example of Fig. 1, the cathode-side node CA_3 is connected to the cathode-side node CA_4. In the example of Fig. 3, when the cathode signal K2 is output from the signal terminal T4, the cathode signal K2 is supplied to each of the light-emitting units UN_3 to UN_4.

[0044] The signal terminal T5 is connected to the cathode-side nodes CA_5 to CA_6. Therefore, in the example of Fig. 3, unlike the example of Fig. 1, the cathode-side node CA_5 is connected to the cathode-side node CA_6. In the example of Fig. 3, when the cathode signal K3 is output from the signal terminal T5, the cathode signal K3 is supplied to each of the light-emitting units UN_5 to UN_6.

[0045] The signal terminal T6 is connected to the cathode side nodes CA_7 to CA_8. Therefore, the cathode side node CA_7 is connected to the cathode side node CA_8. In the example of Fig. 3, when the cathode signal K4 is output from the signal terminal T7, the cathode signal K4 is supplied to each of the light-emitting units UN_7 to UN_8.

[0046] The signal terminal T7 is connected to the cathode-side nodes CA_9 to CA_10. Therefore, the cathode-side node CA_9 is connected to the cathode-side node CA_10. In the example of Fig. 3, when the cathode signal K5 is output from the signal terminal T7, the cathode signal K5 is supplied to each of the light-emitting units UN_9 to UN_10.

[0047] The signal terminal T8 is connected to the cathode-side nodes CA_11 to CA_12. Therefore, the cathode-side node CA_11 is connected to the cathode-side node CA_12. In the example of Fig. 3, when the cathode signal K6 is output from the signal terminal T8, the cathode signal K6 is supplied to each of the light-emitting units UN_11 to UN_12.

[0048] As an example, consider a case where, in the test mode of the light-emitting device 10A, an anode signal A1 is output from the signal terminal T2 and a cathode signal K1 is output from the signal terminal T3. In the configuration of Fig. 3, the anode signal A1 and the cathode signal K1 are supplied to both the light-emitting unit UN_1 and the light-emitting unit UN_2. That is, unlike the configuration of Fig. 1, the configuration of Fig. 3 does not allow driving only one of the light-emitting units UN_1 and UN_2.

[0049] In the configuration of Figure 3, even if, for example, one light-emitting element in light-emitting unit UN_1 is abnormal and all light-emitting elements in light-emitting unit UN_2 are healthy, the potential difference between signal terminal T1 and signal terminal T3 will be equal. Therefore, in the configuration of Figure 3, it is not possible to appropriately determine whether or not an abnormality has occurred in each of light-emitting units UN_1 and UN_2 based on the potential difference. For example, in the configuration of Figure 3, it is not possible to detect that an abnormality has occurred only in light-emitting unit UN_1.

[0050] [Embodiment 1] The inventors of the present application have created a novel display device (particularly, a novel light-emitting device) to address the above-mentioned problems that arise in the configuration example of FIG. 3 in the reference embodiment. In embodiment 1, the novel display device will be described. FIG. 4 shows an example of the configuration of the display device in embodiment 1. The display device in FIG. 4 is referred to as display device 1P. FIG. 4 is a diagram paired with FIG. 3. FIG. 5 shows an example of signals output from each of multiple signal terminals in display device 1P. FIG. 5 is a diagram paired with FIG. 2.

[0051] The display device 1P includes a light emitting device 10P and a control device 20P. Like the light emitting device 10A, the light emitting device 10P includes 12 light emitting units UN_1 to UN_12. However, unlike the light emitting device 10A, the light emitting device 10P includes six switches SW1 to SW6.

[0052] In this specification, the six switches SW1 to SW6 may be collectively referred to as switches SW. In the example of embodiment 1, when the light emitting device 10P is not operating in the inspection mode, all of the switches SW are in the off (open) state. The switches SW may be any semiconductor switches. In the example of FIG. 4, the switches SW are pMOS (positive metal oxide semiconductor) transistors.

[0053] 4, the switch SW1 corresponds to the light-emitting unit UN_1 and the light-emitting unit UN_2. The switch SW1 is located between the cathode-side node CA_1 and the anode-side node AN_2. Therefore, before the start of the inspection mode, the cathode-side node CA_1 and the anode-side node AN_2 are electrically isolated by the switch SW1.

[0054] The switch SW2 corresponds to the light-emitting units UN_3 and UN_4. The switch SW2 is located between the cathode-side node CA_3 and the anode-side node AN_4. Therefore, before the start of the inspection mode, the cathode-side node CA_3 and the anode-side node AN_4 are electrically isolated by the switch SW2.

[0055] The switch SW3 corresponds to the light-emitting units UN_5 and UN_6. The switch SW3 is located between the cathode-side node CA_5 and the anode-side node AN_6. Therefore, before the start of the inspection mode, the cathode-side node CA_5 and the anode-side node AN_6 are electrically isolated by the switch SW3.

[0056] The switch SW4 corresponds to the light-emitting units UN_7 and UN_8. The switch SW4 is located between the cathode-side node CA_7 and the anode-side node AN_8. Therefore, before the start of the inspection mode, the cathode-side node CA_7 and the anode-side node AN_8 are electrically isolated by the switch SW4.

[0057] The switch SW5 corresponds to the light emitting units UN_9 and UN_10. The switch SW5 is located between the cathode side node CA_9 and the anode side node AN_10. Therefore, before the start of the inspection mode, the cathode side node CA_9 and the anode side node AN_10 are electrically isolated from each other by the switch SW5.

[0058] The switch SW6 corresponds to the light emitting unit UN_11 and the light emitting unit UN_12. The switch SW6 is located between the cathode side node CA_11 and the anode side node AN_12. Therefore, before the start of the inspection mode, the cathode side node CA_11 and the anode side node AN_12 are electrically isolated by the switch SW6.

[0059] As described above, one switch SW corresponds to two light-emitting units UN in embodiment 1. Therefore, when the above-mentioned N is an even number, the light-emitting device 10P only needs to have N / 2 switches.

[0060] The drive unit in light emitting device 10P is referred to as drive unit 120P. Drive unit 120P differs from drive unit 120 in that it further includes a signal terminal T9. In the example of Fig. 4, signal terminal T9 is connected to each of switches SW1 to SW6.

[0061] Upon receiving a command from the control device 20P, the drive unit 120P outputs a switching control signal TS (see FIG. 5) from a signal terminal T9. In this way, in the display device 1P, the switching control signal TS is supplied to each of the switches SW1 to SW6 via the signal terminal T9.

[0062] When starting the inspection mode of the light emitting device 10P, the control device 20P causes the driving unit 120P to output a switching control signal TS (for example, a High value of TS) as a turn-on signal, which turns on the switches SW1 to SW6.

[0063] So in inspection mode, (i) When the switch SW1 is turned on, the cathode node CA_1 and the anode node AN_2 are connected, (ii) When the switch SW2 is turned on, the cathode node CA_3 and the anode node AN_4 are connected. (iii) When the switch SW3 is turned on, the cathode node CA_5 and the anode node AN_6 are connected. (iv) When the switch SW4 is turned on, the cathode node CA_7 and the anode node AN_8 are connected. (v) When the switch SW5 is turned on, the cathode node CA_9 and the anode node AN_10 are connected to each other, and (iv) When the switch SW6 is turned on, the cathode node CA_11 and the anode node AN_12 are connected to each other.

[0064] When the control device 20P ends the inspection mode, it causes the driving unit 120P to output a switching control signal TS (for example, a low value of TS) as a turn-off signal, thereby turning off the switches SW1 to SW6.

[0065] Therefore, at the end of the inspection mode, (i) When the switch SW1 is turned off, the cathode node CA_1 and the anode node AN_2 are electrically isolated from each other. (ii) When the switch SW2 is turned off, the cathode node CA_3 and the anode node AN_4 are electrically isolated from each other. (iii) When the switch SW3 is turned off, the cathode node CA_5 and the anode node AN_6 are electrically isolated from each other. (iv) When the switch SW4 is turned off, the cathode node CA_7 and the anode node AN_8 are electrically isolated from each other. (v) When the switch SW5 is turned off, the cathode node CA_9 and the anode node AN_10 are electrically isolated from each other, and (iv) When the switch SW6 is turned off, the cathode node CA_11 and the anode node AN_12 are electrically isolated from each other.

[0066] (First operation example of display device 1P) 6 is a diagram illustrating a first operation example of the display device 1P. In the following description, any one of the multiple direct units UN in the light emitting device 10P will be referred to as a first light emitting unit. The direct unit corresponding to the first light emitting unit will be referred to as a second light emitting unit. FIG. 6 illustrates a case where the light emitting unit UN1 is the first light emitting unit and the light emitting unit UN2 is the second light emitting unit.

[0067] In this specification, the anode-side node of the first light-emitting unit is referred to as the first anode-side node, and the cathode-side node of the first light-emitting unit is referred to as the first cathode-side node. In the example of Figure 6, the anode-side node AN_1 is the first anode-side node, and the cathode-side node CA_1 is the first cathode-side node.

[0068] In this specification, the anode-side node of the second light-emitting unit is referred to as the second anode-side node, and the cathode-side node of the second light-emitting unit is referred to as the second cathode-side node. In the example of Figure 6, the anode-side node AN_2 is the second anode-side node, and the cathode-side node CA_2 is the second cathode-side node.

[0069] In the example of embodiment 1, the same anode signal is supplied from the driving unit 120P to the first light-emitting unit and the second light-emitting unit. Therefore, in the example of embodiment 1, the first anode-side node is connected to the second anode-side node. In the light-emitting device 10P, the anode-side node AN_1 is connected to the anode-side node AN_2. Therefore, the same anode signal A1 is supplied to the anode-side node AN_1 and the anode-side node AN_2 via the signal terminal T2.

[0070] In the example of embodiment 1, the same cathode signal is supplied from the driving unit 120P to the first light-emitting unit and the second light-emitting unit. Therefore, in the example of embodiment 1, the first cathode-side node is connected to the second cathode-side node. In the light-emitting device 10P, the cathode-side node CA_1 is connected to the cathode-side node CA_2. Therefore, the same cathode signal K1 is supplied to the cathode-side node CA_1 and the cathode-side node CA_2 via the signal terminal T3.

[0071] Additionally, in the example of embodiment 1, a switch is provided so that the connection state between the first cathode-side node and the second anode-side node can be changed by the switch. Therefore, in the example of embodiment 1, the switch is located between the first cathode-side node and the second anode-side node.

[0072] In the light emitting device 10P, the switch SW1 is located between the cathode node CA_1 and the anode node AN_2. Therefore, as described above, when the control device 20P starts the inspection mode of the light emitting device 10P, the control device 20P connects the cathode node CA_1 and the anode node AN_2 by turning on the switch SW1 in the light emitting device 10P.

[0073] 6, in the test mode, (i) an anode signal A1 is supplied to the anode-side nodes AN_1 and AN_2, and (ii) a cathode signal K1 is supplied to the cathode-side nodes CA_1 and CA_2. As described above, the switch SW1 is in the on state.

[0074] As a result, in the example of Fig. 6, the inspection current flows along the path of "anode side node AN_1 → cathode side node CA_1 → switch SW1 → anode side node AN_2 → cathode side node CA_2." In this way, in the example of Fig. 6, the inspection current flows from light-emitting unit UN1 to light-emitting unit UN2 via switch SW1.

[0075] In the example of FIG. 6, the control device 20P determines whether or not an abnormality has occurred in each of the light-emitting units UN1 and UN2 based on the test current.

[0076] As described above, the light-emitting device 10P is provided with a switch SW1 located between the light-emitting units UN_1 and UN_2, unlike the light-emitting device 10A of the reference embodiment shown in FIG. 3. As a result, in the example of FIG. 6, unlike the example of FIG. 3, it is possible to determine whether an abnormality has occurred in either the light-emitting unit UN_1 or the light-emitting unit UN_2. As a result, for example, as shown in FIG. 6, if an abnormality has occurred in one light-emitting element in the light-emitting unit UN_1, it is possible to determine that an abnormality has occurred only in the light-emitting unit UN_1.

[0077] As described above, when the control device 20P ends the inspection mode of the light emitting device 10P, the control device 20P causes the light emitting device 10P to turn off the switch SW1, thereby electrically isolating the cathode side node CA_1 and the anode side node AN_2.

[0078] As described above, the display device 1P (particularly the configuration of the light emitting device 10P) newly created by the inventor of the present application makes it possible to detect an abnormality in the light emitting device 10P by a novel method different from conventional methods.

[0079] (Second operation example of display device 1P) Fig. 7 is a diagram for explaining a second operation example of the display device 1P. Unlike the example of Fig. 6, Fig. 7 illustrates a case where the light-emitting unit UN3 is the first light-emitting unit and the light-emitting unit UN4 is the second light-emitting unit.

[0080] 7, the anode side node AN_3 is the first anode side node, the cathode side node CA_3 is the first cathode side node, the anode side node AN_4 is the second anode side node, and the cathode side node CA_4 is the second cathode side node.

[0081] In the light-emitting device 10P, the anode-side node AN_3 is connected to the anode-side node AN_4. Therefore, the same anode signal A1 is supplied to the anode-side node AN_3 and the anode-side node AN_4 through the signal terminal T2. On the other hand, in the light-emitting device 10P, the cathode-side node CA_3 is connected to the cathode-side node CA_4. Therefore, the same cathode signal K2 is supplied to the cathode-side node CA_3 and the cathode-side node CA_4 through the signal terminal T4.

[0082] In the light emitting device 10P, the switch SW2 is located between the cathode node CA_3 and the anode node AN_4. Therefore, as described above, when the control device 20P starts the inspection mode of the light emitting device 10P, the control device 20P connects the cathode node CA_3 and the anode node AN_4 by turning on the switch SW2 in the light emitting device 10P.

[0083] 7, in the test mode, (i) an anode signal A1 is supplied to the anode-side nodes AN_3 and AN_4, and (ii) a cathode signal K2 is supplied to the cathode-side nodes CA_3 and CA_4. As described above, the switch SW2 is in the on state.

[0084] As a result, in the example of Fig. 7, the inspection current flows through the path of "anode side node AN_3 → cathode side node CA_3 → switch SW2 → anode side node AN_4 → cathode side node CA_4." In this way, in the example of Fig. 7, the inspection current flows from light-emitting unit UN3 to light-emitting unit UN4 via switch SW2.

[0085] 7, the control device 20P determines whether or not an abnormality has occurred in each of the light-emitting units UN3 and UN4 based on the test current. As a result, for example, as shown in FIG. 7, when an abnormality has occurred in one light-emitting element in the light-emitting unit UN4, it can determine that an abnormality has occurred only in the light-emitting unit UN_4.

[0086] As described above, when the control device 20P terminates the inspection mode, it causes the light emitting device 10P to turn off the switch SW2, thereby electrically isolating the cathode side node CA_3 and the anode side node AN_4.

[0087] [Software implementation example] The functions of the display devices 1 to 1P (hereinafter referred to as "devices") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly control devices 20 to 20P).

[0088] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0089] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0090] In addition, some or all of the functions of each of the control blocks can be realized by a logic circuit. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of one aspect of the present disclosure. In addition, the functions of each of the control blocks can also be realized by, for example, a quantum computer.

[0091] The processes described in the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0092] 〔summary〕 A light-emitting device according to a first aspect of the present disclosure includes a plurality of light-emitting units, each of which is composed of a plurality of light-emitting elements connected in series and in a forward direction. The plurality of light-emitting units includes a first light-emitting unit and a second light-emitting unit corresponding to the first light-emitting unit. A first anode-side node, which is the anode-side node of the first light-emitting unit, is connected to a second anode-side node, which is the anode-side node of the second light-emitting unit. A first cathode-side node, which is the cathode-side node of the first light-emitting unit, is connected to a second cathode-side node, which is the cathode-side node of the second light-emitting unit. The light-emitting device further includes a switch located between the first cathode-side node and the second anode-side node.

[0093] A display device according to a second aspect of the present disclosure may include the light emitting device according to the first aspect and a control device that controls the light emitting device.

[0094] In a display device according to aspect 3 of the present disclosure, in aspect 2, the control device may connect the first cathode side node and the second anode side node by turning on the switch of the light-emitting device when starting an inspection mode to inspect the first light-emitting unit and the second light-emitting unit in the light-emitting device for abnormalities.

[0095] In a display device according to aspect 4 of the present disclosure, in aspect 3, the control device may electrically isolate the first cathode side node and the second anode side node by causing the light-emitting device to turn off the switch when the inspection mode is terminated.

[0096] In a display device according to a fifth aspect of the present disclosure, in any one of the second to fourth aspects, the light emitting device may be a backlight of the display device.

[0097] In the method for inspecting a light emitting device according to the sixth aspect of the present disclosure, the light emitting device comprises a plurality of light emitting units, each of which is composed of a plurality of light emitting elements connected in series in a forward direction, the plurality of light emitting units including a first light emitting unit and a second light emitting unit corresponding to the first light emitting unit, a first anode side node which is an anode side node of the first light emitting unit is connected to a second anode side node which is an anode side node of the second light emitting unit, a first cathode side node which is a cathode side node of the first light emitting unit is connected to a second cathode side node which is a cathode side node of the second light emitting unit, the light emitting device further comprises a switch located between the first cathode side node and the second anode side node, The inspection method includes a step of connecting the first cathode side node and the second anode side node by turning on the switch when starting an inspection mode to inspect whether or not there are any abnormalities in the first light-emitting unit and the second light-emitting unit in the light-emitting device.

[0098] [Additional Notes] One aspect of the present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of one aspect of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0099] 1P display device 10P light emitting device 20P control device D1_1~D12_6 Light emitting elements D1_1 to D1_6 (examples of light-emitting elements constituting the first light-emitting unit) D2_1 to D2_6 (examples of light-emitting elements constituting the second light-emitting unit) D3_1 to D3_6 (another example of the light-emitting element constituting the first light-emitting unit) D4_1 to D4_6 (another example of the light-emitting elements constituting the second light-emitting unit) UN_1~UN_12 Lighting Unit UN_1 Light-emitting unit (an example of the first light-emitting unit) UN_2 Light-emitting unit (an example of the second light-emitting unit) UN_3 Lighting unit (another example of the first light-emitting unit) UN_4 Light-emitting unit (another example of the second light-emitting unit) AN_1~AN_12 Anode side nodes CA_1~CA_12 cathode side nodes AN_1 (an example of the first anode side node) AN_2 (an example of the second anode side node) AN_3 (another example of the first anode side node) AN_4 (Another example of the second anode side node) CA_1 Cathode side node (example of the first cathode side node) CA_2 cathode node (example of second cathode node) CA_3 Cathode node (another example of the first cathode node) CA_4 Cathode node (another example of a second cathode node) SW1 to SW6 switches SW1 (An example of a switch located between the first cathode node and the second cathode node) SW2 (Another example of a switch located between the first and second cathode nodes)

Claims

1. A light emitting device including a plurality of light emitting units, each of which is composed of a plurality of light emitting elements connected in series and in a forward direction, The plurality of light-emitting units include a first light-emitting unit and a second light-emitting unit corresponding to the first light-emitting unit; a first anode-side node of the first light-emitting unit connected to a second anode-side node of the second light-emitting unit; a first cathode node of the first light-emitting unit connected to a second cathode node of the second light-emitting unit; The light emitting device further comprises a switch located between the first cathode node and the second anode node.

2. The light emitting device according to claim 1; a control device that controls the light-emitting device.

3. 3. The display device of claim 2, wherein the control device connects the first cathode side node and the second anode side node by turning on the switch in the light-emitting device when starting an inspection mode to inspect whether or not there are any abnormalities in the first light-emitting unit and the second light-emitting unit in the light-emitting device.

4. 4. The display device according to claim 3, wherein the control device electrically isolates the first cathode-side node and the second anode-side node by causing the light-emitting device to turn off the switch when the inspection mode is terminated.

5. The display device according to claim 2 , wherein the light emitting device is a backlight of the display device.

6. A method for inspecting a light emitting device, comprising: The light emitting device includes a plurality of light emitting units, each of which is configured by a plurality of light emitting elements connected in series in a forward direction; The plurality of light-emitting units include a first light-emitting unit and a second light-emitting unit corresponding to the first light-emitting unit; a first anode-side node of the first light-emitting unit connected to a second anode-side node of the second light-emitting unit; a first cathode node of the first light-emitting unit connected to a second cathode node of the second light-emitting unit; The light emitting device further includes a switch located between the first cathode node and the second anode node; The inspection method includes: An inspection method including a step of connecting the first cathode side node and the second anode side node by turning on the switch when starting an inspection mode for inspecting whether or not there is an abnormality in the first light-emitting unit and the second light-emitting unit in the light-emitting device.

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