JP2006049301A - Lamp system and back light unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lamp system suppressing the influence of electrode loss to be as low as possible. <P>SOLUTION: The lamp system is provided with two or more external electrode type lamps 20, a lighting circuit 40 carrying out stationary lighting of these external electrode type lamps 20 at a specified lighting frequency and a managing means managing by feed back control so that the temperature of the electrodes 31 and 32 do not exceed 120°C when the external electrode type lamps 20 are lit. The lighting circuit 40 can light the external electrode type lamps 20 to have the lighting frequency variable. The managing means 50 is provided with a sensor 52 measuring the temperature of the electrode 32 and an instructing part 54 instructing the variation in the lighting frequency to the lighting circuit 40 according to the measured temperature of the sensor 52. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lamp system using a dielectric barrier discharge type lamp having an electrode outside a glass bulb and a backlight unit using the lamp system.

Conventionally, a light source for a backlight unit of a liquid crystal display device has been mainly a cold cathode type lamp (hereinafter referred to as an “internal electrode type lamp”) provided with an electrode inside a glass bulb. Dielectric barrier discharge type lamps having electrodes externally (hereinafter referred to as “external electrode type lamps” to be distinguished from internal electrode type lamps) have been studied.
This is because, for example, when a backlight unit is configured using a plurality of lamps, an internal electrode type lamp requires a ballast for each lamp, whereas an external electrode type lamp does not require the ballast. Therefore, the lighting circuit and wiring for lighting the lamp are simplified.

Since this external electrode type lamp is configured to supply electric power from an external electrode to the discharge space in the glass bulb through the glass bulb, if the temperature of the electrode rises during lamp lighting, Loss that part does not contribute to light emission, that is, electrode loss increases.
As a technique for suppressing the temperature rise, Patent Document 1 discloses an external electrode lamp in which a heat dissipation member is provided on the surface of an electrode.
JP 2001-76682 A

However, the conventional technology in which a heat radiating member is provided on the electrode can suppress the temperature rise of the electrode at the time of lamp lighting, and as a result, the electrode loss is suppressed, but the lamp is lit in an optimal state. Is hard to say.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a lamp system and a backlight unit capable of lighting a lamp in a state where electrode loss due to temperature is suppressed as much as possible.

  In order to achieve the above object, a lamp system according to the present invention includes a dielectric barrier discharge type lamp having an electrode outside a glass bulb, and a temperature of the electrode when the lamp is steadily lit at 120 ° C. And management means for managing so as not to exceed. Thus, the lamp can be lit so that the electrode temperature does not exceed 120 ° C. during steady lighting.

Alternatively, the lamp system according to the present invention includes a dielectric barrier discharge type lamp provided with an electrode outside the glass bulb, and management means for managing the temperature of the electrode when the lamp is steadily lit by feedback control. It is characterized by having. Thus, the lamp can be lit so that the electrode temperature does not exceed 120 ° C. during steady lighting.
On the other hand, the lamp system includes a lighting circuit for lighting the lamp so that a lighting frequency can be changed, and the management means includes a sensor for measuring the temperature of the electrode, and a lighting frequency according to the temperature measured by the sensor. And an instruction unit for instructing the lighting circuit to make a change.

The indicating unit increases the lighting frequency when the temperature measured by the sensor is 115 ° C. or higher, and decreases the lighting frequency when the temperature measured by the sensor is 80 ° C. or lower. It is characterized by instructing.
Alternatively, the management unit includes a cooling unit that cools the electrode, a sensor that measures the temperature of the electrode, and an operation instruction unit that operates the cooling unit when the temperature measured by the sensor reaches a predetermined temperature. It is characterized by comprising.

On the other hand, the lamp system according to the present invention is a dielectric barrier discharge type lamp having an electrode outside the glass bulb, and is lit so that the temperature of the electrode does not exceed 120 ° C. when the lamp is steadily lit. And a lighting circuit to be operated. Thus, the lamp can be lit so that the electrode temperature does not exceed 120 ° C. during steady lighting.
Furthermore, the backlight unit according to the present invention is characterized by including the lamp system configured as described above.

  In the lamp system according to the present invention, it has been found by the inventors that the electrode loss tends to increase when the electrode temperature exceeds 120 ° C. Therefore, the lamp system according to the present invention turns on the lamp so that the temperature of the electrode does not exceed 120 ° C. when the lamp is turned on, so that an optimum state with little electrode loss is obtained.

Hereinafter, a lamp system according to the present invention will be described.
1. FIG. 1 is a schematic diagram of a lamp system according to an embodiment.
As shown in FIG. 1, the lamp system 1 includes a plurality of external electrode lamps 20 and a lighting circuit that steadily lights these external electrode lamps 20 at a predetermined lighting frequency (sometimes simply referred to as “frequency”). 40 and management means 50 for managing the temperature of the electrodes 31 and 32 so as not to exceed 120 ° C. when the external electrode type lamp 20 is turned on.

The plurality of external electrode lamps 20 are housed in the case 12. The storage state is arranged substantially parallel to the vertical direction in a state where the axis of the external electrode lamp 20 is horizontal. Each external electrode lamp 20 is electrically connected in parallel to the lighting circuit 40. The backlight unit 10 is the one in which the external electrode lamp 20 is incorporated in the case 12.
The lighting circuit 40 is supplied with power from a DC power source 49, and turns on the external electrode lamp 20 at a predetermined lighting frequency by constant current control, and a frequency switching unit 44 that switches the lighting frequency to at least three types. With.

  The management means 50 manages the temperature of the electrodes 31 and 32 when the external electrode lamp 20 is steadily lit so as not to exceed 120 ° C. by feedback control, and the temperature of the electrode 32 of the external electrode lamp 20 is controlled. And an instruction unit 54 for instructing the lighting circuit 40 to switch the lighting frequency of the external electrode lamp 20 during steady lighting according to the temperature of the electrode 32 measured by the sensor 52.

2. Schematic Configuration of Backlight Unit FIG. 2 is a schematic perspective view showing the configuration of the backlight unit according to the present embodiment. In the drawing, in order to show the internal structure, a part of the diffusion plate 13, the diffusion sheet 14, and the lens sheet 15 is cut out.
As shown in FIG. 2, the backlight unit 10 includes a straight tubular external electrode lamp 20 arranged in 16 rows at predetermined intervals in the vertical direction (Y direction in the figure), and these external electrode lamps. A box-shaped case 12 that houses 20 and has a front surface opened, and a front panel 16 that covers the opening of the case 12 are provided.

The case 12 is made of, for example, polyethylene terephthalate (PET) resin, and a reflective surface is formed on the inner surface thereof by depositing a metal such as silver. Further, the front panel 16 that covers the opening of the case 12 is formed by laminating a diffusion plate 13, a diffusion sheet 14, and a lens sheet 15, and has translucency.
The diffusion plate 13 and the diffusion sheet 14 in the front panel 16 scatter and diffuse the light emitted from the external electrode type lamp 20, and the lens sheet 15 is the light diffused by the diffusion plate 13 and the diffusion sheet 14. Is converted into light in a direction parallel to the normal line of the sheet 15. And it is comprised so that the light emitted from the external electrode type lamp 20 by this front panel 16 may irradiate the front as uniform parallel light over the whole surface (light emitting surface) of the front panel 16.

The temperature of the electrode 32 is measured in the vicinity of one electrode (here, the electrode 32) of the uppermost external electrode lamp 20 among the plurality of external electrode lamps 20 on the inner peripheral surface of the case 12. A sensor 52 for mounting is attached.
The mounting position of the sensor 52 is a position where the temperature of the electrodes 31 and 32 of the external electrode type lamp 20 where the temperature tends to be highest can be measured. That is, when the external electrode type lamp 20 has its axial center arranged in the X direction (direction parallel to the long side of the case 12), the temperature of the external electrode type lamp 20 at the top is the air in the case 12. Therefore, the temperature of the electrodes 31 and 32 of the external electrode lamp 20 can be measured at any position.

Note that the external electrode lamps may be arranged in parallel in the X direction in a state where the axis is parallel to the Y direction. In this case, the position of the sensor is a position for measuring the temperature of the upper electrode in any of the external electrode type lamps.
Further, as the sensor 52, an inexpensive non-contact type that measures a normal ambient temperature or the like can be used. In this case, since the temperature of the electrodes 31 and 32 is not directly measured, it is necessary to test the correlation between the temperature measured by the sensor 52 and the temperature of the electrodes 31 and 32 in advance to correct the measured temperature of the sensor 52. . Regarding the correlation between the temperature measured by the sensor 52 and the temperature of the electrodes 31 and 32, for example, a contact type sensor (for example, fluorescent light) is connected to the electrodes 31 and 32 of the external electrode type lamp 20 positioned at the uppermost position. A fiber thermometer (FL-2000, manufactured by Anritsu Keiki Co., Ltd.) is brought into contact, and the temperature measured by the fluorescent optical fiber thermometer is compared with the temperature measured by the sensor 52. If the ambient temperature around the sensor 52 may affect the measurement temperature, the correlation under the desired ambient temperature may be investigated and corrected.

3. Next, the configuration of the external electrode lamp 20 will be described.
FIG. 3 is a diagram showing the configuration of the external electrode lamp 20 according to the present embodiment, and is shown in a cross-sectional view so that the inside can be seen.
As shown in FIG. 3, the external electrode lamp 20 includes a glass bulb 21 in which both ends of a straight tube-shaped glass tube are sealed, and electrodes 31 and 32 provided on both ends of the glass bulb 21. Is provided.

The glass bulb 21 is made of, for example, borosilicate glass, and the cross-sectional shape thereof is, for example, a substantially circular shape. The material and the cross-sectional shape of the glass bulb 21 are not limited to this, and the cross-sectional shape may be an ellipse or a polygon, for example.
On the inner peripheral surface of the glass bulb 21, for example, red (Y ₂ O ₃ : Eu), green (LaPO ₄ : Ce, Tb) and blue (BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn) rare earth phosphors. A phosphor film 23 made of is formed.

In the present embodiment, the phosphor film 23 is formed only in a region between the electrodes 31 and 32, that is, a light output region where visible light is emitted.
The electrodes 31 and 32 are made of, for example, aluminum metal foil, and are attached so as to cover the outer periphery of the glass bulb 21 with a conductive adhesive in which metal powder is mixed with silicon resin. As the conductive adhesive, fluorine resin, polyimide resin, epoxy resin, or the like may be used instead of silicon resin.

Moreover, instead of sticking the metal foil to the glass bulb 21 with the conductive adhesive, the electrodes 31 and 32 may be formed by applying a silver paste to the entire circumference of the electrode forming portion of the glass bulb 21, For example, a metal cap may be put on the end of the glass bulb 21.
4). Management Unit and Lighting Circuit As shown in FIG. 1, the management unit 50 includes a sensor 52 that measures the temperature of the electrodes 31 and 32 of the external electrode lamp 20 and an external device that is lit according to a signal (temperature) from the sensor 52. And an instruction unit 54 for instructing the lighting frequency of the electrode type lamp 20. Here, a non-contact type sensor 52 is used, but a contact type sensor may be used.

For example, if the signal (temperature) from the sensor 52 is equal to or higher than a threshold value (specifically, a range of 80 ° C. or higher and 115 ° C. or lower), the instructing unit 54 outputs a “High” signal. If there is, a “Normal” signal is output to the lighting circuit 40, and if the signal from the sensor 52 is less than or equal to the threshold value, a “Low” signal is output to the lighting circuit 40.
Here, the reason why the threshold is set in the range of 80 ° C. or higher and 115 ° C. or lower will be described.

First, the reason why the upper limit is set to 115 ° C. will be described later. When the temperature of the electrodes 31 and 32 of the external electrode lamp 20 exceeds 120 ° C., the electrode loss starts to increase and the lamp life becomes longer than 60,000 hours. This is because it may be shortened.
On the other hand, the reason why the lower limit is set to 80 ° C. is that when the temperature of the electrodes 31 and 32 is 80 ° C. or lower, the coldest spot at the time of steady lighting moves from the approximate center of the glass bulb 21 to the electrodes 31 and 32 side. This is because the mercury vapor pressure in the glass bulb 21 decreases and the luminance of the external electrode lamp 20 decreases.

The lighting circuit unit 42 is a known one, for example, an inverter that generates a high-frequency sine wave high voltage from a DC power source. The external electrode lamp 20 is controlled at a constant current by the lighting circuit 40 and is lit at a constant lighting frequency (for example, 60 kHz).
The lighting circuit 40 can turn on the lamp at three types of lighting frequencies, for example, 40 kHz, 60 kHz, and 80 kHz, and includes a frequency switching unit 44 that switches the lighting frequency. The frequency can be switched to three types according to the signal. Note that the lighting frequency here is an example, and other lighting frequencies may be used.

  That is, when the “High” signal is input from the instruction unit 54, the lighting circuit 40 lights the external electrode lamp 20 at the highest frequency (80 kHz) among the three types, and the “Normal” signal is output from the instruction unit 54. Is input, the external electrode lamp 20 is turned on at an intermediate frequency (60 kHz), and when the “Low” signal is input from the instruction unit 54, the external electrode lamp 20 is turned on at the lowest frequency (40 kHz). The external electrode lamp 20 is lit by switching the frequency by the frequency switching unit 44 so as to be lit.

5. Regarding electrode temperature Conventionally, it has been already found that the electrode loss increases as the electrode temperature increases, and that this electrode loss is related to the lamp current, the electrode area, the lighting frequency, and the characteristics of the glass material. . On the other hand, the inventors conducted various studies in order to grasp the relationship between the electrode temperature and the electrode loss. As a result, from the relationship between the voltage applied to the series equivalent resistance when the external electrode lamp described later and the internal electrode lamp described below are represented by an equivalent circuit and the electrode temperature, a temperature at which the electrode loss is minimized is found. The temperature was 120 ° C.

Hereinafter, the background of the inventors finding the temperature (120 ° C.) will be described.
The inventors determined the relationship between the voltage applied to the series equivalent resistance in the external electrode type lamp and the internal electrode type lamp and the electrode temperature. Hereinafter, how to obtain the relationship between the voltage applied to the series equivalent resistance in these lamps and the electrode temperature and the concept thereof will be described.
(1) About Internal Electrode Lamp FIG. 4 is a diagram for explaining how to obtain the relationship between the voltage applied to the series equivalent resistance in the internal electrode lamp and the electrode temperature.

  The internal electrode type lamp 920 shown in FIG. 5A is a lamp having a pair of electrodes 931 and 932 in a glass bulb 921, and a cold cathode type is used for both the electrodes 931 and 932. When the state at the time of steady lighting is represented by an equivalent circuit, it is regarded as a resistance R (this resistance is a “series equivalent resistance”) R shown in FIG. In order to turn on the internal electrode type lamp 920, a ballast is necessary. Generally, the internal electrode type lamp 920 has a capacitor (indicated by “ballast capacitor” in the figure) as shown in FIG. ) 930 is used.

(2) External Electrode Type Lamp FIG. 5 is a diagram for explaining how to obtain the relationship between the voltage applied to the series equivalent resistance in the external electrode type lamp and the electrode temperature.
The external electrode type lamp 20 shown in FIG. 6A has electrodes 31 and 32 outside the glass bulb 21, and the electrodes 31 and 32 and portions of the glass bulb 21 having the electrodes 31 and 32 (dielectric and When a steady-state lighting state is expressed by an equivalent circuit, a pair of capacitors C and resistors connected in series between the capacitors C (this resistance is shown in FIG. 5B). , “Series equivalent resistance”.)

When the external electrode type lamp 20 is turned on, unlike the internal electrode type lamp 920 described above, it does not need to be provided with a ballast because it includes the capacitor C, and as shown in FIG. Connected to a high frequency power supply.
(3) Measurement method and concept of voltage applied to the series equivalent resistance of each lamp First, the internal electrode type lamp 920 and the external electrode type lamp 20 are connected to a high frequency power source as shown in FIG. The voltage applied to the series equivalent resistance and the electrode temperature were measured. Although not shown in FIG. 6, the internal electrode type lamp 920 is connected to the high frequency power source together with the ballast 930.

The voltage applied to the series equivalent resistance is measured by measuring the lamp voltage Vla, the lamp current Ila, and the lamp power Wla in the connection state of FIG. 6 using a wattmeter, and from these measured values, the following formula (1 ) To (3), reactive power Q, series equivalent resistance R, and series equivalent reactance X are calculated.
Reactive power Q = √ {(Vla) ² * (Ila) ² − (Wla) ² } (1)
Series equivalent resistance R = Wla / (Ila) ² (2)
Series equivalent reactance X = Q / (Ila) ² (3)
Here, the reason why the series equivalent resistance R and the series equivalent reactance X are separated is to separate components of the resistance R contributing to light emission and the reactance X not contributing to light emission when the lamp is lit.

In the internal electrode type lamp 920, the series equivalent resistance R is the resistance of the discharge space and is the lamp itself. In the external electrode type lamp 20, the electrode equivalent to the series equivalent reactance X which is the electrode portion of the lamp 20 is excluded. The resistance Rc of the capacitor portion and the resistance (corresponding to the lamp) R of the discharge space are obtained.
That is, the series equivalent resistance R includes the resistance Rc of the dielectric portion of the electrode in the external electrode type lamp 20.

Therefore, the voltage VR applied to the series equivalent resistance R of the external electrode lamp 20 is obtained by multiplying the series equivalent resistance R by the lamp current Ila.
(4) Measurement results The internal electrode type lamp 920 and the external electrode type lamp 20 are connected and lit as shown in FIG. 6, and the voltage VR applied to the series equivalent resistance R is obtained based on the above concept. The electrode temperature of was measured. Here, the lamp voltage is changed in order to change the electrode temperature. The specifications and lighting conditions of each lamp are shown below.

A. Specification of external electrode type lamp The external electrode type lamp 20 has three kinds of electrodes (sizes), and the specification of the lamp used for the measurement is shown below (see FIG. 3).
Valve dimensions: Outer diameter D1: 4 mm, Inner diameter D2: 3 mm,
Length L2: 300mm
Type of rare gas: Neon 95% Argon 5%
Noble gas filling pressure ・ ・ ・ 8kPa
Electrode length L1 15 mm, 20 mm, 25 mm
B. Specification of internal electrode type lamp The basic specification of the internal electrode type lamp 920 is the same as that of the external electrode type lamp 20 described above, and the lengths of the electrodes 931 and 932 arranged inside the glass bulb 921 are 8 mm. is there.

C. Lamp lighting conditions Lighting frequency: 80 kHz
Atmospheric temperature at lighting ... Room temperature (25 ℃)
D. Measurement Results As described above, the voltage VR applied to the series equivalent resistance R of the internal electrode type lamp 920 and the external electrode type lamp 20 and the electrode temperature at that time were measured. The electrode temperature in the internal electrode type lamp 920 is the wall surface temperature of the glass bulb 921 where the electrodes 931 and 932 are present.

FIG. 7 is a diagram showing the relationship between the voltage VR applied to the series equivalent resistance R in each lamp and the electrode temperature.
As shown in the figure, for the external electrode type lamp 20, the voltage VR applied to the series equivalent resistance R is initially lowered with the increase of the electrode temperature in common with the three types of electrode lengths L1. However, the voltage VR applied to the series equivalent resistance R increases as the electrode temperature increases from a certain temperature.

  This phenomenon in which the lamp voltage starts to increase from a certain temperature is not observed in the internal electrode type lamp 920 (indicated as “CCFL” in FIG. 7). In the basic idea for calculating the lamp voltage, the difference between the external electrode type lamp 20 and the internal electrode type lamp 920 is a resistance Rc corresponding to the electrodes 31 and 32 of the external electrode type lamp 20. Therefore, the ramp voltage increased because the resistance Rc of the electrodes 31 and 32 of the external electrode lamp 20 increased, and the inventors considered that this ramp voltage increase corresponds to the electrode loss. This electrode loss is considered to be caused by a change in dielectric characteristics of the glass material constituting the glass bulb 21.

Therefore, when the external electrode type lamp 20 is lit, if the lamp is lit at a temperature lower than the temperature at the inflection point in the relationship between the voltage VR applied to the series equivalent resistance R and the electrode temperature, the electrode loss increases. Never start. That is, the external electrode type lamp 20 can be lit in an optimum state in which electrode loss is minimized.
(6) Optimal temperature for minimum electrode loss Next, the reason why the temperature at which the electrode loss can be suppressed is set to 120 ° C. will be described. First, the temperature indicating the inflection point varies depending on the size of the electrode (here, the electrode length L1), and the range is 90 ° C. to 110 ° C.

  On the other hand, the electrode loss is considered to change depending on the size of the electrode, but the temperature at which the electrode loss starts to increase is considered to be constant regardless of the size of the electrode. In view of this, in the relationship between the voltage VR applied to the series equivalent resistance R shown in FIG. 7 and the electrode temperature, the inflection temperature varies depending on the size of the electrode. This is considered to be a variation due to some kind of influence.

Therefore, the temperature at which the electrode loss starts to increase as the electrode temperature rises is considered to be about 110 ° C. However, considering the variation in the experiment and the fact that the electrode loss does not increase sharply from the inflection point, the external electrode lamp is kept in a state where the electrode loss is kept to a minimum if it does not exceed 120 ° C. It is considered that 20 can be turned on.
(7) Lamp life As described above, the electrode loss is considered to be caused by a change in the dielectric characteristics of the glass material constituting the glass bulb 21, and the life of the external electrode type lamp 20, specifically, the electrode 31 is considered. , 32 is considered to have an influence on the lifetime. Therefore, the inventors examined the electrode temperature and the life characteristics of the lamp (hereinafter also referred to as life time).

FIG. 8 is a diagram showing the relationship between the electrode temperature and the lamp life time.
From the figure, it can be seen that the higher the electrode temperature, the shorter the life time of the external electrode lamp 20. This increases the electrode loss as the electrode temperature increases, and leads to an increase in the loss (dielectric loss) of the glass material in the portion corresponding to the inner peripheral portion of the electrodes 31 and 32 in the glass bulb 21, and as a result. It is considered that, for example, a pinhole or the like is generated in the portion, and the life time is shortened.

  On the other hand, considering the life of the liquid crystal display device, the life required for the lamp used in the backlight unit 10 (regardless of the external electrode type lamp or the internal electrode type lamp) is 60,000 hours. Therefore, in order to satisfy this requirement, the external electrode lamp 20 may be lit at an electrode temperature of the external electrode lamp 20 of 120 ° C. or less. The temperature substantially coincides with the temperature at the inflection point in the relationship between the voltage VR applied to the equivalent resistance R and the electrode temperature.

<Modification>
Although the present invention has been described based on the embodiments, the content of the present invention is not limited to the specific examples shown in the above embodiments. For example, the following modifications are possible. Can be implemented.
1. Regarding the management means In the above embodiment, the electrode temperature is a threshold value (80 ° C. to 115 ° C.) as the management means for preventing the temperatures of the electrodes 31 and 32 of the external electrode lamp 20 during lighting from exceeding 120 ° C. However, the present invention is not limited to this.

FIG. 9 is a schematic view showing a lamp system in a modified example.
As shown in the figure, the lamp system 101 includes a plurality of external electrode lamps 20 and management means for managing the electrode temperature of the external electrode lamps 20 by feedback control. The plurality of external electrode lamps 20 are turned on by a lighting circuit having the lighting circuit unit 42 described in the embodiment, for example.

As shown in FIG. 9, the management means includes a cooling means 156 for cooling the electrodes 31 and 32, a sensor 52 for measuring the temperature of the electrodes 31 and 32, and the measured temperature being a predetermined temperature, for example, 115 ° C. or more. And an operation instruction unit 154 that instructs the cooling means 156 to operate.
Here, the cooling means 156 uses a fan and cools the electrodes 31 and 32 by an air cooling method. If the glass bulb 21 is likely to be cooled by operating the fan, the inside of the case 12 shown in FIG. What is necessary is just to take measures, such as partitioning the light emission area between the electrodes 31 and 32 of the glass bulb 21 so that the convection by the fan does not go to the light emission area side of the glass bulb 21.

Here, the air cooling type cooling means has been described, but other cooling means, for example, a water cooling method using a liquid may be used. In the case of the water cooling method, the piping and the like are complicated, but the inside of the case can be sealed, and for example, dust and dust can be prevented from adhering to the electrodes 31 and 32.
2. Regarding the lighting circuit In the embodiment and the above modification, the electrode temperature is managed by the management means when the electrode temperature is likely to exceed 120 ° C., but the electrode temperature during steady lighting should not exceed 120 ° C. In addition, the external electrode type lamp may be lit by setting the electrode length, the lamp current, and the like. That is, from the beginning, an external electrode lamp and a lighting circuit for lighting it may be designed.

3. Regarding the sensor In the embodiment, one sensor 52 for measuring the temperature of the electrode is provided in total, but a sensor may be provided in the vicinity of the electrode so that the electrode temperature of all the external electrode type lamps can be measured. good.
Further, two sensors may be provided for each external electrode lamp so that the temperature of two electrodes in each external electrode lamp is measured, or only the temperature of one electrode is measured. As described above, one sensor may be provided for one external electrode type lamp.

Further, when sensors are provided to measure the electrode temperatures of all the external electrode lamps, a cooling means 156 as shown in Modification 1 is provided for each electrode so as to control the temperature for each external electrode lamp. Also good.
4). Backlight Unit In the embodiment, the backlight unit 10 includes the external electrode lamp 20, the case 12, the front panel 16, and the like. For example, the backlight unit 10 includes a lighting circuit for lighting the external electrode lamp. It may be a backlight unit. In this case, for example, the lighting circuit may be installed on the outer surface of the case 12, or may be installed separately from the case, and the installation position is not particularly limited.

Furthermore, the backlight unit using the lamp system according to the present invention also includes management means, but the installation location of the instruction unit, operation instruction unit, etc. constituting this is not particularly limited, for example, You may install in the outer surface of case 12. FIG.
5. About the Lamp The direct-type backlight unit 10 has been described as an example in which the lamp according to the present invention is applied. However, the present invention is naturally applicable to a light guide plate-type backlight unit. In this case, the glass bulb may be curved in a U shape or an L shape.

  Furthermore, the lamp according to the present invention may be used as a light source of a general lighting device other than the backlight unit, and the shape thereof is a straight tube shape as in the embodiment, the above-described U shape, L shape, spiral. It may be a shape or the like and is not particularly limited. In the embodiment, the phosphor film 23 is formed in the glass bulb 21, but the present invention can also be applied to, for example, “black light” in which the phosphor film 23 is not formed.

  The present invention can be used as a lamp system and a backlight unit that can minimize the influence of dielectric loss.

It is the schematic of the lamp system which concerns on embodiment. It is a schematic perspective view which shows the structure of the backlight unit which concerns on embodiment. It is a figure which shows the structure of the external electrode type lamp | ramp which concerns on embodiment, Comprising: It shows with sectional drawing so that a mode can be understood inside. It is a figure explaining how to obtain | require the relationship between the voltage concerning the series equivalent resistance in an internal electrode type lamp | ramp, and electrode temperature. It is a figure explaining how to obtain | require the relationship between the voltage concerning series equivalent resistance in an external electrode type lamp | ramp, and electrode temperature. It is the schematic of the method of measuring the voltage concerning a series equivalent resistance. It is a figure which shows the relationship between the voltage VR concerning the series equivalent resistance R in each lamp | ramp, and electrode temperature. It is a figure which shows the relationship between the temperature of an electrode, and the lifetime of a lamp | ramp. It is the schematic which shows the lamp system in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lamp system 10 Backlight unit 20 External electrode type lamp 21 Glass bulb 31, 32 Electrode 40 Lighting circuit 42 Frequency switching part 50 Management means 52 Sensor 54 Instruction part 101 Lamp system 154 Operation instruction part 156 Cooling means

Claims (7)

  A dielectric barrier discharge type lamp having an electrode outside the glass bulb, and a management means for managing the temperature of the electrode so as not to exceed 120 ° C. when the lamp is steadily lit. Lamp system to do.   A lamp system comprising: a dielectric barrier discharge type lamp provided with an electrode outside a glass bulb; and a management means for managing the temperature of the electrode when the lamp is steadily lit by feedback control. A lighting circuit for lighting the lamp so that the lighting frequency can be changed,
The said management means is provided with the sensor which measures the temperature of the said electrode, and the instruction | indication part which instruct | indicates the change of a lighting frequency to the said lighting circuit according to the temperature measured by the said sensor. Lamp system as described in.   The instruction unit instructs to increase the lighting frequency when the temperature measured by the sensor is 115 ° C. or higher, and to decrease the lighting frequency when the temperature measured by the sensor is 80 ° C. or lower. The lamp system according to claim 3.   The management means includes a cooling means for cooling the electrode, a sensor for measuring the temperature of the electrode, and an operation instruction unit for operating the cooling means when the temperature measured by the sensor reaches a predetermined temperature. The lamp system according to claim 1, further comprising a lamp system.   A dielectric barrier discharge type lamp provided with an electrode outside the glass bulb, and a lighting circuit for lighting the electrode so that the temperature of the electrode does not exceed 120 ° C. when the lamp is steadily lit. Lamp system to do.   A backlight unit comprising the lamp system according to claim 1.

Images