Lighting device

Abstract

To provide a lighting device that can extend the lighting time of a light fixture and also indicate when it should be turned off. [Solution] To achieve the above objective, an illumination device according to one embodiment of the present invention comprises a first light-emitting element, a first group of light-emitting elements, a switching unit, and a control unit. The first group of light-emitting elements consists of a first group including at least one light-emitting element and a second group including at least one light-emitting element, connected in series between the positive and negative terminals of a battery, and emits first illumination light. The switching unit switches between a first state in which the first group and the second group are lit, and a second state in which either the first group or the second group is lit. The control unit outputs a control signal to the switching unit to switch between the first state and the second state based on the remaining battery charge.

Description

Technical Field

[0001] The present invention relates to a lighting device applicable to a lighting fixture or the like driven by a battery.

Background Art

[0002] Conventionally, in a lighting fixture equipped with a battery such as a tunnel lamp installed in a tunnel, since the capacity of the battery is limited, there has been a problem that it is desired to make the lighting time as long as possible. Also, when the battery runs out, the light suddenly goes out, which is dangerous because the surroundings suddenly become dark.

[0003] For example, Patent Document 1 discloses a lighting device provided with control means for gradually reducing the luminance of a light source according to the remaining amount of a battery for the light source in a closed space. By this, it is intended to lengthen the lighting time of the light source when power is supplied from the battery. Also, Patent Document 2 discloses an emergency power supply circuit for a light-emitting diode traffic signal that switches to the power charged in advance when the main power supply of the traffic signal fails and continuously blinks the signal during a power failure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Thus, in a lighting device that controls the lighting of a battery with a limited capacity, there is a need for a technology that can notify the user that the remaining battery level is low and at what timing the light source will go out.

[0006] In view of the above circumstances, the object of the present invention is to provide a lighting device that can extend the lighting time of a light fixture and also indicate when it should be turned off. [Means for solving the problem]

[0007] To achieve the above objective, an illumination device according to one embodiment of the present invention comprises a first group of light-emitting elements, a switching unit, and a control unit. The first group of light-emitting elements comprises a first group and a second group, each including at least one light-emitting element that emits a first illumination light, and the first group and the second group are connected in series between the positive and negative electrodes of the battery. The switching unit switches from a first state in which the first group and the second group are lit up to a second state in which either the first group or the second group is lit up. The control unit outputs a control signal to the switching unit to switch from the first state to the second state based on the remaining battery charge.

[0008] The above-described lighting device comprises a first light-emitting element, a first group of light-emitting elements, a switching unit, and a control unit. The first group of light-emitting elements has a first group and a second group, each containing at least one light-emitting element that emits a first illumination light, and the first group and the second group are connected in series between the positive and negative terminals of a battery. The switching unit switches from a first state in which the first group and the second group are lit to a second state in which either the first group or the second group is lit. The control unit outputs a control signal to the switching unit to switch from the first state to the second state based on the remaining battery level. This makes it possible to notify the user when the battery level is low and when the light source will be turned off.

[0009] The above-described lighting device may further include a second light-emitting element connected in parallel with the first group of light-emitting elements, which emits a second illumination light different from the first illumination light. In this case, the operating voltage of the second light-emitting element may be lower than that of the first group of light-emitting elements. The control unit may, based on the remaining battery charge, switch the switching unit from the second state to a third state in which the first group of light-emitting elements is turned off and the second light-emitting element is turned on.

[0010] The second group described above may be arranged between the first group and the negative electrode. In this case, the switching unit may be arranged on a bypass line connected between the first group and the second group and the negative electrode, and may include a first switching element that switches the conduction or non-conductivity of the bypass line.

[0011] The switching unit may include a second switching element connected between the second light-emitting element and the negative electrode, which switches the second light-emitting element on or off.

[0012] The control unit may compare the remaining battery capacity with a first threshold and output a control signal to the switching unit to switch from the first state to the second state if the remaining battery capacity is lower than the first threshold.

[0013] The control unit may compare a second threshold, which is lower than the first threshold, with the remaining battery charge, and if the remaining battery charge is lower than the second threshold, it may output a control signal to the switching unit to switch from the second state to the third state.

[0014] The control unit may have a time measurement unit for measuring the lighting time of the second light-emitting element, and when the lighting time exceeds a predetermined threshold or when a predetermined time is reached, it may output a control signal to the switching unit to switch from the third state to a fourth state in which the first light-emitting element group and the second light-emitting element are turned off.

[0015] The above control unit may have a constant current circuit that supplies drive currents to the above first light emitting element group and the above second light emitting element. In this case, the control unit compares a third threshold value lower than the above second threshold value with the remaining amount of the battery, and when the remaining amount of the battery is lower than the third threshold value, outputs a control signal for stopping the drive current to the constant current circuit.

[0016] The above first light emitting element group may be white LEDs. In this case, the above second light emitting element may be red LEDs.

Advantages of the Invention

[0017] As described above, according to the present invention, it becomes possible to extend the lighting time of the lighting fixture and to notify the timing of turning off the light.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram showing a circuit diagram of a lighting device. [Figure 2] It is a flowchart showing the control process of the lighting device. [Figure 3] It is a diagram showing another example of the circuit diagram of the lighting device. [Figure 4] It is a flowchart showing the control process of the lighting device.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments according to the present invention will be described while referring to the drawings.

[0020] FIG. 1 is a diagram showing a circuit diagram of a lighting device 100 according to the present invention.

[0021] In FIG. 1, the lighting device 100 has a battery 1, a control unit 5, a first light emitting element group 10, a second light emitting element 20, a first switching element 30, and a second switching element 40.

[0022] For example, the lighting device 100 is installed on a railway and controls the auxiliary lights (first light-emitting group 10 and second light-emitting group 20) used during railway vehicle inspections. In this embodiment, the lighting device 100 controls the number of auxiliary lights that are lit using power from the battery 1, and the timing of when they are turned off.

[0023] The first light-emitting element group 10 has a first group 11 and a second group 12, each containing at least one light-emitting element that emits a first illumination light. In this embodiment, the first group 11 and the second group 12 are connected in series between the positive and negative terminals of the battery 1. In this embodiment, the first group 11 consists of five light-emitting elements (LEDs), and the second group 12 is positioned between the first group 11 and the negative terminal of the battery 1 and consists of four light-emitting elements (LEDs). In this embodiment, the first light-emitting element group 10 consists of LEDs that emit white illumination light.

[0024] In this embodiment, a first switching element 30 (FET) is placed on a bypass line connected between the first group 11 and the second group 12 and the negative terminal of the battery 1. The first switching element 30 is controlled by the microcontroller 60, and when the first switching element 30 is turned on, the bypass line becomes conductive and the second group 12 turns off.

[0025] The second light-emitting element 20 is connected in parallel with the first light-emitting element group 10 and emits a second illumination light. In this embodiment, a second switching element 40 (FET) is connected in series between the second light-emitting element 20 and the negative terminal of the battery 1. The second switching element 40 is controlled by a microcontroller 60, and the second light-emitting element lights up when the second switching element 40 is turned on. In this embodiment, the second light-emitting element 20 uses a light-emitting element with a lower operating voltage than the first light-emitting element group 10 (for example, a red LED).

[0026] In the following description, the state in which the first group 11 and the second group 12 are lit is referred to as the first state, the state in which only the first group 11 is lit is referred to as the second state, and the state in which the first light-emitting group 10 is off and only the second light-emitting group 20 is lit is referred to as the third state. Furthermore, the state in which both the first light-emitting group 10 and the second light-emitting group 20 are off is referred to as the fourth state.

[0027] The control unit 5 includes a power supply IC 50, a microcontroller 60, and a constant current circuit 70, and outputs a control signal to the first switching element 30 or the second switching element 40 to switch between a first state, a second state, a third state, or a fourth state based on the remaining voltage of the battery 1.

[0028] The power supply IC 50 receives the DC voltage output from the battery 1 as input to its input terminal, controls the input DC voltage to a constant voltage, and outputs it. In this embodiment, the power supply IC 50 outputs a DC voltage of 3.3V from its output terminal to the microcontroller 60.

[0029] The microcontroller 60 is driven by the DC voltage output from the power supply IC 50 and monitors the DC voltage output from the battery 1. In this embodiment, the microcontroller 60 monitors the voltage divided by resistors 61 and 62.

[0030] The microcontroller 60 also has three output terminals (IO pins in Figure 1) and switches the first switching element 30 or the second switching element 40 on or off based on the current voltage of the battery 1. A pull-up resistor 63 is connected to each of the three output terminals. Note that resistors 61 and 62 and the pull-up resistor 63 may also be included in the control unit 5.

[0031] In this embodiment, under normal conditions (for example, when the battery voltage is 60V or higher), the first switching element 30 and the second switching element 40 are in the off state, and the first light-emitting element group 10 (9 elements in Figure 1) is lit.

[0032] In this embodiment, when the voltage is 40V or more and less than 60V, the microcontroller 60 turns on the first switching element 30, reducing the number of lit first light-emitting elements in the first group 10, and illuminating only the first group 11 (5 elements in Figure 1). Also, when the voltage is 30V or more and less than 40V, the microcontroller 60 turns on the second switching element 40, thereby illuminating the second light-emitting elements 20 (3 elements in Figure 1).

[0033] The microcontroller 60 also measures the illumination time from the moment the second light-emitting element 20 lights up. In this embodiment, when the illumination time of the second light-emitting element 20 has elapsed to 10 minutes, the EN pin of the control IC 71, which will be described later, is set to LOW.

[0034] The constant current circuit 70 includes a control IC 71, a third switching element (FET) 72, a diode 73, a coil 74, and a capacitor 75. The control IC 71 performs constant current operation by controlling the on / off state of the third switching element 72. A Zener diode 76 (20V in Figure 1) is connected to the VIN pin of the control IC 71.

[0035] In this embodiment, the control IC 71 sets the EN pin to HIGH when power is supplied from the battery 1, thereby controlling the third switching element 72. Also in this embodiment, when a control signal is supplied to the EN pin from the microcontroller 60 indicating that the illumination time of the second light-emitting element 20 has elapsed for 10 minutes, the control IC 71 sets the EN pin to LOW, which turns off the third switching element 72, thereby turning off the first light-emitting element group 10 and the second light-emitting element 20.

[0036] In this embodiment, the drive voltage of the control IC 71 is set to 10V.

[0037] In this embodiment, the first switching element 30 and the second switching element 40 correspond to a switching unit that can switch from a first state in which the first group and the second group are lit to a second state in which either the first group or the second group is lit. In this embodiment, the microcontroller 60 corresponds to a time measurement unit that measures the lighting time of the second light-emitting element.

[0038] Figure 2 is a flowchart showing the control process of the lighting device 100.

[0039] As shown in Figure 2, when power is supplied from battery 1, the microcontroller 60 sets the EN pin of the control IC 71 to HIGH and outputs a control signal to control to the first state (the state in which the first light-emitting element group 10 is lit) (step 101).

[0040] The microcontroller 60 measures the battery voltage. First, if the battery voltage is 60V or higher (YES in step 102), the first switching element 30 and the second switching element 40 are turned off. As a result, nine white LEDs, which make up the first light-emitting element group 10, light up (step 101).

[0041] Furthermore, if the battery voltage is lower than 60V (NO in step 102) and 40V or higher (YES in step 103), the microcontroller 60 turns on the first switching element 30. This results in a second state where only the first group 11 (5 white LEDs) lights up (step 104).

[0042] Furthermore, if the battery voltage is lower than 40V (NO in step 103) and 30V or higher (YES in step 105), the microcontroller 60 turns on the second switching element 40. As a result, the first light-emitting element group 10 turns off, and the third state is reached in which three red LEDs light up (step 106).

[0043] The microcontroller 60 starts counting up when the red LED lights up (step 107). When the microcontroller 60 has counted up the red LED for 10 minutes (YES in step 108), it outputs a control signal to the constant current circuit 70 to stop the drive current of the first light-emitting group 10 and the second light-emitting element 20. That is, the EN pin of the control IC 71 goes LOW, turning off the third switching element 72. This results in the fourth state where the first light-emitting group 10 and the second light-emitting element 20 are turned off (step 109).

[0044] Furthermore, in this embodiment, there is a voltage drop of 20V across the Zener diode 76, and the control IC 71 cannot operate unless at least a drive voltage of 10V is applied to the VIN pin of the control IC 71. Therefore, if the battery voltage falls below 30V before 10 minutes have elapsed since the count-up started (NO in step 105), the first light-emitting element group 10 and the second light-emitting element 20 are turned off.

[0045] The number and color of the first light-emitting group 10 and the second light-emitting group 20 are not limited. For example, the first light-emitting group 10 may emit incandescent-colored light. Depending on the number and forward voltage of the first group 11 (which is the first light-emitting group 10) and the second light-emitting group 20, the voltage of the battery 1 may become lower than the forward voltage of the first group 11, and only the second light-emitting group 20 may light up. Similarly, it is possible that the second light-emitting group 20 may turn off and only the first group 11 will light up. For this reason, it is desirable to set the working time of workers performing various tasks such as railway vehicle inspections, the amount of light required for the work, and the time until the backup lights (first light-emitting group 10 and second light-emitting group 20) turn off, taking into consideration notifications to workers.

[0046] In this embodiment, the determination in step 102 whether the battery voltage is 60V or higher or lower corresponds to the first threshold. The value of the first threshold (battery voltage of 60V) is not limited, but it is desirable that it be lower than the range of battery voltage used during normal operation of railways, etc. (for example, 70V to 150V in the case of railways).

[0047] In this embodiment, the determination in step 103 whether the battery voltage is 40V or higher or lower corresponds to a second threshold. In this embodiment, the determination in step 105 whether the battery voltage is 30V or higher or lower corresponds to a third threshold. In this embodiment, the determination in step 108 whether 10 minutes have elapsed since the red LED counted up corresponds to a predetermined time for the illumination of the second light-emitting element.

[0048] Figure 3 shows the circuit diagram of the lighting device 200. As shown in Figure 3, the lighting device 200 is a circuit diagram that does not use a microcontroller 60 with a timer function. In the following description, parts that are the same as the configuration and operation of the lighting device 100 described in the above embodiment will be omitted or simplified.

[0049] In the lighting device 200 shown in Figure 3, the control unit 205 includes a power supply IC 50, a constant current circuit 70, a first comparator 210, and a second comparator 220.

[0050] The first comparator 210 compares the voltages input to its positive input terminal and negative input terminal. In this embodiment, the positive input terminal of the first comparator 210 is input to 2V, which is obtained by dividing the 3.3V from the power supply IC 50 by resistors 211 and 212. The negative input terminal of the first comparator 210 is input to a voltage obtained by dividing the voltage from the battery 1 by resistors 213 and 214.

[0051] The first comparator 210 turns off the first switching element 30 when the voltage input to the negative input terminal is greater than the voltage input to the positive input terminal (2V). The first comparator 210 also turns on the first switching element 30 when the voltage input to the negative input terminal is lower than the voltage input to the positive input terminal (2V).

[0052] The second comparator 220 compares the voltages input to its positive input terminal and negative input terminal. In this embodiment, the positive input terminal of the second comparator 220 is input to 2V, which is obtained by dividing the 3.3V from the power supply IC 50 by resistors 211 and 212. The negative input terminal of the second comparator 220 is input to a voltage obtained by dividing the voltage from the battery 1 by resistors 221 and 222.

[0053] The second comparator 220 turns off the second switching element 40 when the voltage input to the negative input terminal is greater than the voltage input to the positive input terminal (2V). The second comparator 220 also turns on the second switching element 40 when the voltage input to the negative input terminal is lower than the voltage input to the positive input terminal (2V).

[0054] Figure 4 is a flowchart showing the control process of the lighting device 200 in Figure 3.

[0055] As shown in Figure 4, power is supplied from battery 1, and the first light-emitting element group 10 lights up (step 201). Also, if the battery voltage is 60V or higher (YES in step 202), no output is produced from the first comparator 210 and the second comparator 220, so the first switching element 30 and the second switching element 40 are turned off. As a result, the first state is reached in which nine white LEDs, which are the first light-emitting element group 10, light up (step 201).

[0056] Furthermore, if the battery voltage is lower than 60V (NO in step 202) and 40V or higher (YES in step 203), the first comparator 210 turns on the first switching element 30. This results in a second state where only the first group 11 (5 white LEDs) lights up (step 204).

[0057] Furthermore, if the battery voltage is lower than 40V (NO in step 203) and 30V or higher (YES in step 205), the second comparator 220 turns on the second switching element 40. As a result, the first light-emitting element group 10 turns off, and the second light-emitting element 20 (3 red LEDs) lights up, resulting in a third state (step 206).

[0058] Furthermore, in this embodiment, there is a voltage drop of 20V across the Zener diode 76, and the control IC 71 cannot operate unless at least a drive voltage of 10V is applied to the VIN pin of the control IC 71. Therefore, when the battery voltage falls below 30V (NO in step 205), the first light-emitting element group 10 and the second light-emitting element 20 are turned off (step 207).

[0059] As described above, by switching the number of LEDs in series in response to a decrease in battery voltage, the forward voltage of the LEDs can be lowered, reducing power consumption and extending the illumination time. Furthermore, when the battery voltage drops even further, switching to red LEDs can indicate the remaining time until the lights turn off. In other words, reducing the number of white LEDs allows for low-intensity illumination and extends battery life, while switching to red LEDs notifies the worker when the backup lights will turn off and prevents the surrounding area from becoming dark due to a sudden dim.

[0060] Furthermore, since this lighting device does not require a dimming terminal to control the dimming rate of the light fixture, it is possible to achieve the same results as equipment using a dimming terminal by reducing the number of first light-emitting element groups, without using a dimming terminal. In addition, the circuit configuration can be simplified by not using a dimming terminal. Moreover, when using a dimming terminal, it is necessary to have all colors of light-emitting elements to change the color of the light-emitting elements, but in this invention, it is only necessary to prepare light-emitting elements that emit illumination light of a specific color.

[0061] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made. Furthermore, the configurations of each embodiment and its modified form may be combined. [Explanation of symbols]

[0062] 1…Battery 5, 205... Control Unit 10…First light-emitting element 11…Group 1 12…Group 2 20...Second light-emitting element 30…First switching element 40…Second switching element 50…Power IC 60... Microcontroller 70... Constant current circuit 71…Control IC 72…Third switching element 100, 200... lighting devices 210...First comparator 220...Second comparator

Claims

1. A first group of light-emitting elements has a first group and a second group, each including at least one light-emitting element that emits a first illumination light, and the first group and the second group are connected in series between the positive and negative electrodes of a battery, A switching unit that can switch from a first state in which the first group and the second group are lit up to a second state in which either the first group or the second group is lit up, A control unit that outputs a control signal to the switching unit to switch from the first state to the second state based on the remaining battery charge, A lighting device equipped with the following features.

2. The lighting device according to claim 1, further, It has a second light-emitting element connected in parallel with the first group of light-emitting elements, which emits a second illumination light different from the first illumination light, The second light-emitting element has a lower operating voltage than the first group of light-emitting elements. The control unit outputs a control signal to the switching unit, based on the remaining battery charge, to switch from the second state to a third state in which the first group of light-emitting elements turns off and the second group of light-emitting elements turns on. Lighting device.

3. A lighting device according to claim 1, The second group is positioned between the first group and the negative electrode. The switching unit is located on a bypass line connected between the first group and the second group and the negative electrode, and includes a first switching element that switches the conduction or non-conductivity of the bypass line. Lighting device.

4. The lighting device according to claim 2, The switching unit includes a second switching element connected between the second light-emitting element and the negative electrode, which switches the second light-emitting element on or off. Lighting device.

5. The lighting device according to claim 2, The control unit compares a first threshold value for the remaining battery charge with the actual remaining battery charge. If the remaining battery charge is lower than the first threshold value, the control unit outputs a control signal to the switching unit to switch from the first state to the second state. Lighting device.

6. A lighting device according to claim 5, The control unit compares a second threshold, which is lower than the first threshold, with the remaining battery charge. If the remaining battery charge is lower than the second threshold, it outputs a control signal to the switching unit to switch from the second state to the third state. Lighting device.

7. A lighting device according to claim 6, The control unit has a time measurement unit that measures the illumination time of the second light-emitting element, and when the illumination time exceeds a predetermined time, or when the predetermined time is reached, it outputs a control signal to the switching unit to switch from the third state to a fourth state in which the first light-emitting element group and the second light-emitting element are turned off. Lighting device.

8. A lighting device according to claim 6, The control unit has a constant current circuit that supplies the drive current to the first group of light-emitting elements and the second group of light-emitting elements. The control unit compares a third threshold, which is lower than the second threshold, with the remaining battery charge. If the remaining battery charge is lower than the third threshold, it outputs a control signal to the constant current circuit to stop the drive current. Lighting device.

9. The lighting device according to claim 2, The first group of light-emitting elements is a white LED, The second light-emitting element is a red LED. Lighting device.

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