JP2007026962A - Light emitting system using solar power generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To emit light over a long period of time at high energy efficiency by obtaining a great light emitting area while having low generation of heat and low consumption of power. <P>SOLUTION: A light emitting system has an illumination unit 3 with an exterior housing formed by a protective cover attached to a part of a supporting pillar 2 of a street light 1, a planar light emitting panel 4 is integrated on a light projected surface side of an illumination unit 3 and a planar solar power panel 6 is integrated on a light receiving surface side. A field emission type light emitting device with the low generation of heat and the low consumption of the power is used as the light emitting panel 4, a power accumulating device 5 is laminated on a back surface side of the light emitting panel 4 and furthermore, a lamination structure with a solar battery panel 6 laminated on the power accumulating device 5 is taken. Thus, downsizing is made possible while securing a great light emitting area, light emission over a long period of time can be made possible by suppressing power consumption and the light emitting system superior in energy efficiency with little power loss can be realized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting system using solar power generation in which power of solar power generation is supplied to a light emitting device to emit light.

Conventionally, a stand-alone power supply using solar power generation using a solar cell has been put into practical use, and application to various applications has been attempted. For example, in Patent Document 1, as an application to a night illumination device, a condenser, a control unit, and a light-emitting diode are arranged on the back side of a solar cell, and the condenser is a thin (less than 5 mm thickness) electric double layer capacitor. By doing so, space saving, weight reduction, and workability are improved.
JP 2002-151717 A

  However, the illumination device disclosed in Patent Document 1 uses an LED (light emitting diode) as a light emitting device. LEDs are point light sources with strong directivity, and are suitable for illumination light sources that require directivity, such as spotlights and downlights. However, they are not necessarily suitable when a wide light emitting area is required. Absent.

  In this case, in order to obtain illumination light that can illuminate the whole brightly using LEDs, it is necessary to spread a large number of LEDs in a planar shape, but in order to reduce the size, the mounting density must be increased. In other words, heat is trapped and the luminous efficiency is greatly reduced, which causes a problem in practical use. For example, when the ambient temperature of the LED rises above about 80 ° C., the light emission luminance is reduced to about 1/3 and cannot be practically used. Furthermore, since it is necessary to arrange a large number of LEDs for surface emission, power consumption is increased, and it is difficult to emit light for a long time only by photovoltaic power generation.

  The present invention has been made in view of the above circumstances, and it is possible to obtain a photovoltaic power generation capable of obtaining a wide light emitting area while having low heat generation and low power consumption, and capable of light emission for a long time with high energy efficiency. It aims at providing the used light emission system.

  In order to achieve the above object, a light-emitting system using solar power generation according to the present invention is a light-emitting system using solar power generation in which generated power from a solar cell is supplied to a light-emitting device to emit light. Comprising a field emission type light emitting device that excites a phosphor with emitted electrons from a cold cathode electron emission source, and stores the solar cell and the electric power generated by the solar cell, and stores the stored electric power as the field emission. An electric storage device for supplying to a light emitting device and the field emission light emitting device are sequentially stacked.

  The power storage device is preferably a lithium ion-based power storage device, and includes a light detection sensor on the light receiving surface side of the solar cell, determines the start of lighting of the light emitting device according to the output of the light detection sensor, and stores the power at the start of lighting. It is desirable to control the light emission luminance of the light emitting device according to the remaining capacity of the device.

  When controlling the light emission luminance of the light emitting device, it is desirable to calculate the average power when the light emitting device is turned on based on the remaining capacity of the power storage device, and calculate the target luminance based on this average power.

  Average power can be calculated by calculating the amount of usable energy based on the remaining capacity and dividing this amount of usable energy by the lighting time from the start of lighting to the end of lighting of the light emitting device. The power can be calculated based on the target power calculated by regulating the power within a preset upper and lower limit range.

  The lighting time of the light emitting device is based on the preset time, the time due to the difference between the lighting end time set according to the calendar and the lighting start time determined based on the output of the light detection sensor, and the output of the light detection sensor The time determined by the difference between the determined lighting start time and the previous lighting end time based on the output of the light detection sensor, the current lighting start time determined based on the output of the light detection sensor, and the light detection sensor It can be set to any one of the times depending on the difference from the moving average value of the lighting end time based on the output.

  Since the light emitting system using photovoltaic power generation according to the present invention uses a field emission light emitting device that generates less heat as the light emitting device, the temperature characteristics are not deteriorated even if the power storage device and the solar cell are stacked. The light emitting system can be miniaturized, a wide light emitting area can be obtained while low heat generation and low power consumption, and long light emission can be achieved with high energy efficiency.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 13 relate to an embodiment of the present invention, FIG. 1 is a configuration diagram of a streetlight, FIG. 2 is a configuration diagram of a luminance control system, FIG. 3 is a functional block diagram of luminance control, and FIG. FIG. 5 is an explanatory diagram showing the relationship between the voltage and the remaining capacity of the power storage device, FIG. 5 is an explanatory diagram showing the relationship between the voltage and the power of the power storage device, FIG. FIG. 8 is a flowchart of a main control routine, FIG. 9 is a flowchart of a target brightness calculation routine, FIG. 10 is a flowchart of a lighting end determination routine, and FIG. FIG. 12 is a flowchart of an end determination routine, FIG. 12 is a flowchart of a discharge determination routine, and FIG.

  FIG. 1 shows an example in which a light-emitting system using photovoltaic power generation according to the present invention is applied to a streetlight 1. This streetlight 1 has a lighting unit 3 in which an external housing is formed by a protective cover on an upper part of a support column 2. Configured. The lighting unit 3 has a light projecting surface for projecting illumination light on the ground and a light receiving surface for receiving light from the sun, and a flat light emitting panel 4 is provided on the light projecting surface side. A planar solar cell panel 6 is provided on the light receiving surface side and generates electricity with sunlight. Between the light emitting panel 4 and the solar cell panel 6, a planar power storage device 5 that stores power generated by the solar cell panel 6 is disposed.

  The light-emitting panel 4 is a field emission light-emitting device with low heat generation and low power consumption. In the lighting unit 3, the power storage device 5 is stacked on the back side of the light-emitting panel 4 (surface opposite to the light projecting surface). Furthermore, a solar cell panel 6 is laminated on the electricity storage device 5. With this laminated structure, a power generation element, a power storage element, and a light emitting element are integrated and miniaturized, and an illumination system that can sufficiently secure illumination light at night with an independent power source using sunlight is realized. On the light receiving surface side where the solar cell panel 6 is disposed, a light detection sensor 7 made of, for example, a photodiode is disposed in order to detect sunlight and recognize daytime and nighttime.

  As shown in FIG. 2, the light-emitting panel 4 maintains the inside of the insulating substrates 10 and 11 facing each other at a predetermined interval in a vacuum state, and the cathode electrode 15 having the cold cathode electron emission source 16 in this vacuum state. A basic structure in which a grid-like gate electrode 20 and an anode electrode 25 having a phosphor 26 excited and emitted by an electron beam are arranged in order from the base surface side laminated on the electricity storage device 5 toward the light projecting surface side. ing.

  The insulating substrate 11 on the light projecting surface side is formed from a transparent substrate such as a glass substrate. In this embodiment, a field emission lamp having a tripolar structure including a cathode electrode, a gate electrode, and an anode electrode will be described. However, a field emission lamp having a bipolar structure that does not use a gate electrode may be used.

  The cathode electrode 15 is made of a conductive material formed on the insulating substrate 10 serving as a base. For example, a metal such as aluminum or nickel is deposited by vapor deposition or sputtering, or a silver paste material is applied and dried and fired. It is formed by doing. On the surface of the cathode electrode 15, emitter materials such as carbon nanotubes, carbon nanowalls, spint type micro cones, metal oxide whiskers and the like are applied in a film shape to form a cold cathode electron emission source 16.

  The gate electrode 20 is a grid-like electrode disposed to face the cathode electrode 15, and is connected to the cold cathode electron emission source 16 formed on the cathode electrode 15 according to the potential difference (gate voltage) with the cathode electrode 15. An electric field is applied to emit electrons. The gate electrode 20 has a large number of fine openings through which electrons emitted from the cold cathode electron emission source 16 pass, and is etched or thinly formed on a conductive thin plate such as a stainless steel material, a nickel material, or an amber material. A large number of openings such as a circle and a rectangle are formed by using a punching method or the like.

  The anode electrode 25 is made of a transparent conductive film (for example, ITO film) disposed on the back surface side of the insulating substrate 11 serving as a light projecting surface, and cold cathode electron emission is performed on the surface facing the gate electrode 20 (cathode electrode 15). A phosphor 26 that is excited and emitted by electrons emitted from the source 16 is applied. The phosphor 26 is formed on the anode electrode 25 by, for example, an ink jet method, a photography method, a precipitation method, an electrodeposition method, or the like.

  Moreover, as the electrical storage device 5 clamped between the light emission panel 4 and the solar cell panel 6, a sheet-type electric double layer capacitor and a lithium ion system electrical storage device are used, for example. Lithium ion power storage devices can easily estimate the remaining capacity from the voltage, and control the brightness of the light-emitting panel 4 in accordance with the remaining capacity, so that they can be lit for a long time with as little charge as possible. Can be made possible.

  Since the illumination unit 3 having the above configuration uses a field emission light emitting device that generates less heat as the light emitting panel 4, the temperature characteristics deteriorate even if the power storage device 5 and the solar cell 6 are stacked and integrated. There is no. In addition, it is possible to reduce the size while ensuring a wide light emitting area, to enable long-time light emission by suppressing power consumption, and to realize a light-emitting system with low energy loss and excellent energy efficiency. it can.

  Next, the controller 50 that controls the lighting unit 3 will be described. The controller 50 is composed of a microcomputer or the like, determines the start of lighting of the light-emitting panel 4 according to the output from the light detection sensor 7, calculates the remaining capacity of the power storage device 5, adjusts the voltage supplied to the light-emitting panel 4, Processing such as calculation of target luminance is performed, and the luminance of the light-emitting panel 4 is controlled via the drive circuit 30.

  In FIG. 2, the controller 50 and the drive circuit 30 are shown separately. However, these are preferably configured as an integral unit, and in the lighting unit 3, in the vicinity of the lighting unit 3, or in the column 2. Installed inside.

  Functions related to the luminance control of the controller 50 are shown in the functional block diagram of FIG. 3, and include a lighting time calculation unit 51, a remaining capacity calculation unit 52, an average power calculation unit 53, a target luminance calculation unit 54, a pulse period calculation unit 55, This can be represented by the drive pulse calculation unit 56. Then, the drive circuit 30 is controlled by the drive pulse from the drive pulse calculation unit 56, and the luminance of the light emitting panel 4 is controlled. In the present embodiment, the drive circuit 30 controls the luminance by driving the cathode electrode 15 of the light-emitting panel 4 in a pulsed manner, which will be described in detail later.

  Based on the output VP from the light detection sensor 7, the lighting time calculation unit 51 determines the lighting start of the light-emitting panel 4 accompanying the transition from daytime to nighttime, and calculates the lighting time TMLGT from the lighting start to the lighting end. The lighting time TMLGT can be determined by various methods shown in the following (a) to (d), for example.

(A) A specified time (for example, 12 hours) preset in the timer is set as the lighting time TMLGT.

(B) A calendar function is incorporated, and the difference between the lighting start time and the lighting end time set in advance according to the calendar is calculated as the lighting time TMLGT.

(C) The lighting end is determined based on the output VP of the light detection sensor 7, and the current lighting time TMLGT is calculated from the difference between the time when the lighting start is determined and the previous lighting end determination time stored. To do.

(D) The lighting end is determined based on the output VP of the light detection sensor 7, and a moving average value (for example, five times) for a certain period of the lighting end time is stored. Then, the lighting time TMLGT is calculated from the time when the lighting start is determined and the moving average value of the lighting end time.

  While the lighting time TMLGT according to (a) can be simplified in terms of control, the lighting time TMLGT according to the calendar function of (b) can be set to an appropriate lighting state according to the change in the sunshine time. Moreover, in the lighting time TMLGT by (c) and (d), the lighting time according to an actual state can be ensured.

  The remaining capacity calculation unit 52 reads the voltage VB of the power storage device 5 and calculates the remaining capacity SOC. As shown in FIG. 4, the remaining capacity SOC of the electricity storage device 5 is prepared in advance by storing a map or the like in which the relationship between the voltage of the electricity storage device 5 and the remaining capacity is stored, and referring to the map using the voltage VB as a parameter. The remaining capacity SOC is calculated.

The average power calculation unit 53 multiplies the difference between the current remaining capacity SOC of the power storage device 5 and the minimum available remaining capacity SOCL by the energy capacity EBFL of the power storage device 5 as shown in the following equation (1). Then, the usable energy amount EBPS is obtained, and as shown in the following expression (2), the usable energy amount EBPS is divided by the lighting time TMLGT to calculate the average power WTLGT.
EBPS = (SOC−SOCL) × EBFL (1)
WTLGT = EBPS / TMLGT (2)

  As shown in FIG. 5, the relationship between the voltage VB (or remaining capacity SOC) of the power storage device 5 and the power is set in advance, and the average power WTLGT is calculated from the voltage VB (or remaining capacity SOC) of the power storage device. You may make it do.

The target luminance calculation unit 54 calculates the target power WTTGT by restricting the average power WTLGT to the set range, and calculates the target luminance CDTGT based on the target power WTTGT. The target power WTTGT is calculated so that the average power WTLGT is between the minimum value WTMIN and the maximum value WTMAX, as shown in the following equations (3) to (5). The minimum value WTMIN and the maximum value WTMAX are set according to the frequency range (for example, 60 to 200 Hz) of the drive pulse that drives the light emitting panel 4.
When WTLGT <WTMIN: WTTGT = WTMIN (3)
When WTMIN ≦ WTLGT ≦ WTMAX: WTTGT = WTLGT (4)
When WTLGT> WTMAX: WTTGT = WTMAX (5)

  As shown in FIG. 6, the target luminance CDTGT is set in advance in a map or the like with the relationship between the power consumed by the light-emitting panel 4 and the light emission luminance, and the target luminance CDTGT is obtained by referring to the map using the target power WTTGT as a parameter. Is calculated.

In this case, the target luminance CDTGT may be gradually increased according to the elapsed time from the start of lighting in order to prevent a sense of incongruity when the light emitting panel 4 is turned on and to reduce power consumption. That is, as shown in FIG. 7, a luminance coefficient KST that increases with the passage of time from the start of lighting until the set time TCCE is reached is introduced, and the luminance coefficient is added to the target luminance CDTGT as shown in the following equation (6). By multiplying by KST, the target luminance CDTGT is gradually increased.
CDTGT = KST × CDTGT (6)

  However, when the target luminance CDTGT is gradually increased using the luminance coefficient KST, the average power WTLGT is fixed as a preset initial value WTLHT1 from the start of lighting until the set time TCCE is reached. Then, after the set time TCCE has elapsed, the above-described usable energy amount EBPS and the lighting time TMLGT are calculated, and the average power WTLGT is calculated according to the equation (2).

  The above target luminance CDTGT is converted into a pulse signal output to the drive circuit 30 via the pulse period calculation unit 55 and the drive pulse calculation unit 56. In the present embodiment, the luminance control of the light emitting panel 4 by the controller 50 is performed by a frequency modulation method in which the frequency is varied with a constant pulse width, and a pulse when a gate voltage is applied in a pulse form from the gate electrode 20 to the cathode electrode 15. The light emission luminance is controlled by varying the period while keeping the pulse width of the signal constant.

  The relationship between the luminance of the light emitting device 4 and the pulse driving cycle is set in advance and stored in the controller 50, and as the pulse driving cycle becomes longer, the light emitting luminance decreases in a functional manner. The relationship between the luminance and the pulse driving cycle is obtained in advance through experiments or simulations and mapped, and is calculated as a pulse cycle T1 with respect to the target luminance CDTGT by the pulse cycle calculation unit 55.

  The drive pulse calculation unit 56 generates a pulse signal having a constant pulse width in the pulse cycle T 1 calculated by the pulse cycle calculation unit 55 and outputs the pulse signal to the drive circuit 30. As a result, the drive circuit 30 is driven by a pulse signal whose pulse width is constant and the period T1 changes according to the target brightness CDTGT, and brightness control by frequency modulation is performed.

  In this case, it is desirable that the target luminance CDTGT is updated at regular intervals (for example, every hour) while the light emitting panel 4 is turned on, and the controllability is improved in response to disturbance of the power consumption of the light emitting panel 4. be able to.

  Further, in the luminance control of the light emitting panel 4 by the frequency modulation method, the voltage applied to the gate electrode 20 may be varied by the period T1 to control the light emission luminance, but in this embodiment, the voltage applied to the gate electrode 20 is controlled. Is constant, and the drive circuit 30 switches the impedance on the cathode electrode 15 side between a low impedance state and a high impedance state. As a result, the voltage applied from the gate electrode 20 to the cathode electrode 15 can be changed in a pulsed manner while simplifying the power supply system, and the light emission luminance of the light emitting panel 4 can be controlled.

  As shown in FIG. 2, the drive circuit 30 for converting the cathode impedance mainly includes transistors TR1 and TR2 as switching elements driven by pulse signals from the controller 50, and series resistors R1 and R1 connected to the cathode electrode 15. The cathode impedance is periodically converted between a low impedance state and a high impedance state by switching the series resistors R1 and R2 connected to the cathode electrode 15.

  The pulse signal from the controller 50 is a signal having a cycle of ON (high level) and OFF (low level) of T1 and an OFF time of T2, and this pulse signal is one stage as a pulse signal corresponding to the target luminance CDTGT. It is input to the base of the transistor TR1 of the eye via a bias resistor RB.

  The first-stage transistor TR1 has an emitter grounded, a collector connected to the power supply Vcc via a collector resistor RC, and is connected to the base of the second-stage transistor TR2. Similarly, the second-stage transistor TR2 has an emitter grounded and a collector connected between the resistors R1 and R2 connected in series to the cathode electrode 15. The cathode electrode 15 is grounded through the resistor R1 and the resistor R2.

  One resistor R <b> 1 is a resistor for low impedance, and is set to a resistance value that allows a voltage that generates a current density necessary for light emission of the phosphor 26 to be applied to the cathode electrode 15. The other resistor R2 is set to a high resistance value for high impedance, and is set to a resistance value that makes the cathode current substantially zero.

  Therefore, at time T2 when the pulse signal from the controller 50 is OFF, when the first-stage transistor TR1 is OFF, the second-stage transistor TR2 is ON, the resistor R2 is short-circuited, and the cathode impedance is low impedance due to the resistor R1. It becomes a state. As a result, a gate voltage having a constant peak value is applied from the gate electrode 20 to the cathode electrode 15, and the phosphor 26 emits light.

  On the other hand, when the pulse signal from the controller 50 is ON (T1-T2), the first-stage transistor TR1 is turned on and the second-stage transistor TR2 is turned off, and the cathode impedance is determined by the combined resistance of the resistors R1 and R2. It becomes a high impedance state. As a result, the gate electrode 20 and the cathode electrode 15 become the same potential, the emission of electrons from the cold cathode electron emission source 16 is stopped, and the phosphor 26 is brought into a non-light emitting state.

  The above process is repeated and the phosphor 26 emits light intermittently. However, by setting the frequency of the pulse signal to 60 Hz or higher, human luminance is high in luminance when the transistor TR2 is ON. Light emission remains as an afterimage and is recognized as continuous light emission.

  Specifically, the control of the lighting unit 3 by the controller 50 is executed by each control routine shown in the flowcharts of FIGS. Next, each control routine will be described.

  FIG. 8 is a main control routine for controlling the lighting unit 3 to be turned on / off. In the first step S1, the output VP of the light detection sensor 7 is read, and nighttime determination is performed in step S2. In this nighttime determination, when the output VP of the light detection sensor 7 is equal to or lower than a preset threshold value, it is determined that it is nighttime when the lighting panel 4 of the lighting unit 3 is turned on to illuminate.

  If the result of determination in step S2 is that night determination is not established, the routine proceeds from step S2 to step S3, the light emitting panel 4 is turned off, and the routine is exited. On the other hand, when the nighttime determination is made, the process proceeds from step S2 to step S4, and the target luminance calculation routine of FIG. 9 is called to calculate the target luminance CDTGT. In step S5, the light emitting panel 4 is turned on to control the target brightness, and the routine is exited.

  When the target brightness calculation routine of FIG. 9 is called, first, in step S11, the voltage VB of the power storage device 5 is read to calculate the remaining capacity SOC, and in step S12, the usable energy amount EBPS is calculated based on the remaining capacity SOC. (See equation (1) above).

  Next, the process proceeds to step S13, the lighting time TMLGT of the light emitting panel 4 is calculated, and the process proceeds to step S14. Note that the lighting time TMLGT is the specified time set by the timer, the lighting end time by the calendar, and the light detection as described above. It is calculated based on the last lighting end time or the like by the sensor 7.

  In step S14, the average power WTLGT is calculated from the usable energy amount EBPS and the lighting time TMLGT (see equation (2)), and after step S15, the average power WTLGT is set to the frequency range of the drive pulse for driving the light emitting panel 4. The target power WTTGT is calculated by restricting the upper and lower limits between the minimum value WTMIN and the maximum value WTMAX set accordingly.

. The average power WTLGT may be calculated from the voltage VB (or remaining capacity SOC) of the power storage device 5.

  In step S15 subsequent to step S14, the average power WTLGT is compared with the minimum value WTMIN, and if WTLGT <WTMIN, the minimum value WTMIN is calculated as the target power WTTGT in step S16 (WTTTGT = WTMIN), and WTLGT ≧ WTMIN. In step S17, the average power WTLGT is compared with the maximum value WTMAX.

  In step S17, if WTLGT ≦ WTMAX, the average power WTLGT is calculated as the target power WTTGT in step S18 (WTGTGT = WTLGGT), and if WLTGT> WTMAX, the maximum value WTMAX is calculated as the target power WTTGT in step S19. (WTTGT = WTMAX).

  Then, after calculating the target power WTTGT, the process proceeds to step S20, where the target brightness CDTGT corresponding to the target power WTTGT is calculated based on the relationship between the power of the light emitting panel 4 and the light emission brightness (see FIG. 6), and the routine is exited. .

  Thereby, it is variable according to the target luminance CDTGT of the driving cycle T1 of the driving pulse signal for driving the light emitting panel 4, and the luminance control according to the remaining capacity of the power storage device 5 can be performed, improving the energy use efficiency. Long-time lighting can be secured.

  During the lighting of the light emitting panel 4 by the above processing, the lighting end determination routine shown in FIG. 10 is executed in parallel to monitor the voltage state of the power storage device 5. Further, while the light emitting panel 4 is turned off, the charge end determination routine shown in FIG. 11 or the discharge determination routine shown in FIG. 12 is executed to monitor the voltage state of the power storage device 5.

  That is, in the lighting end determination routine shown in FIG. 10, the voltage VB of the power storage device 5 is read in the first step S21, and whether or not the voltage VB of the power storage device 5 is lower than the preset minimum value VBMIN in step S22. Find out. In step S22, if VB ≧ VBMIN, the routine is directly exited. If VB <VBMIN, the lighting panel 4 is turned on in step S23, and the routine is exited.

  That is, even when the amount of electricity stored in the electricity storage device 5 is small due to insufficient illuminance or the like, the electricity storage device 5 is overdischarged by monitoring so that the voltage of the electricity storage device 5 does not fall below the minimum value while the light emitting panel 4 is lit. Therefore, the electricity storage device 5 can be protected.

  In the charging end determination routine shown in FIG. 11, the voltage VB of the electricity storage device 5 is read in the first step S31, and whether or not the voltage VB of the electricity storage device 5 exceeds the preset maximum value VBMAX in step S32. Find out. In step S32, if VB ≦ VBMAX, the routine is directly exited. If VB> VBMAX, charging from the solar cell panel 6 to the power storage device 5 is terminated in step S33, and the routine is exited.

  On the other hand, in the discharge determination routine shown in FIG. 12, the voltage VB of the electricity storage device 5 is read in the first step S41, and the deviation EVB between the preset maximum value VBMAX and the read voltage VB is calculated in step S42. (EVB = VBMAX−VB). Next, it progresses to step S43 and it is investigated whether deviation EVB is less than 0, ie, whether the voltage VB of the electrical storage device 5 is over the maximum value VBMAX.

  In step S43, if EVB ≧ 0 and the voltage VB of the electricity storage device 5 is equal to or lower than the maximum value VBMAX, the routine is exited, and the voltage VB of the electricity storage device 5 exceeds the maximum value VBMAX when EVB <0. If yes, the process proceeds to step S45 and subsequent steps, and the electric storage device 5 is forcibly discharged by turning on the light-emitting panel 4 so that the voltage of the electric storage device 5 becomes equal to or lower than the maximum value VBMAX.

  In this forced discharge process, the light emitting panel 4 is turned on in step S45, and the proportional power is controlled by the deviation EVB in step S46 to calculate the target power. In step S47, the target luminance is calculated based on the target power, feedback control is performed so that the luminance of the light emitting panel 4 becomes the target luminance, and the routine is exited.

  In this forced discharge by the end of charging or lighting of the light emitting panel, even when the amount of power generation of the solar cell panel 6 is increased due to sufficient daily illuminance, overcharging of the electricity storage device 5 can be prevented in advance, The electricity storage device 5 can be protected.

  In the above embodiment, the street lamp 1 has been described as an example. However, the present invention is not limited to this, but road guide board illumination, signs, light-emitting poles of construction sites, road surface guide lights, home use It can be applied to the gate lights of

  FIG. 13 shows an example of application as an indoor lighting system, which is a window frame integrated lighting system. This illumination system is configured by disposing an illumination unit 80 on an upper part of a glass window 70 provided on a wall 60, and the illumination unit 80 includes a planar light-emitting panel 81 having a light-emitting surface facing the indoor side, The power storage device 82 disposed on the back side of the light-emitting panel 81 and the solar cell panel 83 that is exposed to the outdoors and receives sunlight are sequentially stacked. The light-emitting panel 81 is a field emission light-emitting device with low heat generation and low power consumption, similar to the light-emitting panel 4 described above.

  In the window frame integrated lighting system, the power generated by the solar cell panel 83 during the day is charged in the power storage device 82. When there is no power generation by the solar cell panel 83 at night, the light emitting panel 81 is driven by the power from the power storage device 82. Light. The light emission luminance of the light emitting panel 81 can be controlled in the same manner as described above.

  As described above, in this embodiment, since a field emission light-emitting device that generates less heat is used as a light-emitting device, it is possible to reduce the size while securing a wide light-emitting area. The light emission luminance can be appropriately controlled by day / night determination by the detection sensor, and the energy saving effect can be promoted. In addition, it is possible to prevent overdischarge and overcharge of the power storage device even when the illuminance is insufficient or excessive, protect the power storage device, and improve durability.

Streetlight configuration diagram Configuration diagram of brightness control system Functional block diagram of brightness control Explanatory diagram showing the relationship between the voltage of the electricity storage device and the remaining capacity Explanatory drawing which shows the relationship between the voltage of an electrical storage device, and electric power Explanatory drawing which shows the relationship between the electric power of a light emission panel, and light emission brightness | luminance. Explanatory drawing which shows the relationship between the elapsed time after lighting start and a luminance coefficient Main control routine flowchart Flow chart of target brightness calculation routine Lighting end determination routine flowchart Flowchart of charging end determination routine Flow chart of discharge determination routine Configuration diagram showing an example of application to a window frame integrated lighting system

Explanation of symbols

4 Light-emitting panel (field emission light-emitting device)
5 Storage Device 6 Solar Panel 7 Photodetection Sensor 16 Cold Cathode Electron Emission Source 26 Phosphor 50 Controller CDTGT Target Brightness EBPS Usable Energy Amount SOC Remaining Capacity TMLGT Lighting Time WTLGT Average Power WTTGT Target Power

Claims (7)

A light-emitting system using solar power generation that emits light by supplying generated power from a solar cell to a light-emitting device,
The light-emitting device comprises a field emission type light-emitting device that excites a phosphor with emitted electrons from a cold cathode electron emission source,
The solar cell, the electric storage device for storing the electric power generated by the solar cell and supplying the stored electric power to the field emission light emitting device, and the field emission light emitting device are sequentially stacked. A light-emitting system using solar power generation.   2. The light emitting system using solar power generation according to claim 1, wherein the power storage device is a lithium ion power storage device. A light detection sensor is provided on the light receiving surface side of the solar cell,
It is characterized by comprising control means for determining the lighting start of the light emitting device according to the output of the light detection sensor and controlling the light emission luminance of the light emitting device according to the remaining capacity of the power storage device at the time of starting lighting. A light emitting system using solar power generation according to claim 1 or 2. The control means includes
4. The average power when the light emitting device is turned on is calculated based on the remaining capacity, and a target brightness for controlling the light emission brightness of the light emitting device is calculated based on the average power. Luminous system using solar power generation. The control means includes
The amount of usable energy is calculated based on the remaining capacity, and the average power is calculated by dividing the amount of usable energy by a lighting time from the lighting start to the lighting end of the light emitting device. 4. A light emitting system using photovoltaic power generation according to 4. The control means includes
6. The solar power generation according to claim 4 or 5, wherein the target power is calculated by regulating the average power within a preset upper and lower limit range, and the target luminance is calculated based on the target power. The light emitting system. The control means includes
Predetermined time set in advance, lighting end time set according to the calendar and lighting start time determined based on the output of the light detection sensor, current lighting determined based on the output of the light detection sensor The difference between the start time and the previous lighting end time based on the output of the light detection sensor, the current lighting start time determined based on the output of the light detection sensor, and the output of the light detection sensor over a certain period The light emitting system using photovoltaic power generation according to claim 5 or 6, wherein any one of the times based on a difference from the moving average value of the lighting end time based on the lighting end time is set as the lighting time of the light emitting device.

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