JPH11214184A - Lighting method for xenon fluorescent discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting method which provides high brightness and luminance, improves uneven luminance in the axial direction of a tube, and is suitable for a back light function of display equipment. SOLUTION: This device is a lighting method of a xenon fluorescent discharge lamp 7 including a fluorescent discharge tube main body 2 in which rare gas containing xenon gas is sealed and a fluorescent body film 1 is provided on an inner wall face thereof, a pair of electrodes 3, 3' sealed and mounted in opposition to both end sides in the fluorescent discharge tube main body 2, a pair of lead-in wires 4, 4' which are electrically connected with a pair of electrodes 3, 3', respectively, and are led out of the fluorescent discharge tube main body 2 in an air-tight manner, an electricity conducting film 5 arranged like a belt from one end side to the other end side on an outer peripheral face of the fluorescent discharge tube main body 2, and a lead 6 electrically connected with the electricity conducting film 5. In this method, a voltage of a potential difference of 500 V or less is applied to a pair of electrodes 3, 3' sealed and mounted in opposition in the fluorescent discharge tube main body 2, and on the other hand, a dischargeable voltage is applied between at least either of the electrodes 3 (3') and the electricity conducting film 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for lighting a xenon fluorescent discharge lamp suitable for a display device.

[0002]

2. Description of the Related Art As is well known, rare gas fluorescent lamps are widely used as light sources for various display devices such as small scanners and display panels. In addition, with the advancement of functions such as color display of personal computers and printers, there is also a demand for a cathode fluorescent lamp (fluorescent discharge lamp) used as a backlight to have a smaller size, a higher luminance, and a longer life. In the rare gas fluorescent discharge lamps, structural improvements such as the electrode structure have been promoted.On the other hand, rare gases as a discharge medium have also been studied, and mercury-free xenon or mixed systems with xenon have been studied. It is also known to enclose as a rare gas to achieve higher luminance.

[0003] Incidentally, a xenon fluorescent discharge lamp generally adopts a structure as shown in a sectional view of a main part in FIG. That is, the phosphor coating 1 is formed on the light emitting surface of the inner wall of the glass tube.
Is formed, a fluorescent discharge tube main body 2 in which a rare gas containing xenon is sealed, a pair of electrodes 3 and 3 ′ which are sealed opposite to both ends in the fluorescent discharge tube main body 2, and a pair of the electrodes A xenon fluorescent discharge lamp is known which has a pair of lead wires 4 and 4 'which are electrically connected to the fluorescent lamps 3 and 3', respectively, and are led out of the fluorescent discharge tube main body 2 in an airtight manner.

In this xenon fluorescent lamp, a lighting operation is performed by applying a required discharge voltage between the pair of electrodes 3, 3 '. At this time, the positive column becomes linear. Since the light passes through the central portion along the tube axis of the fluorescent discharge tube main body 2, the ultraviolet light is attenuated due to the self-absorption of the sealed gas, so that the luminous efficiency is low.

[0005] In response to the problem of the above luminous efficiency, the following xenon fluorescent discharge lamps have been developed.

The first xenon fluorescent discharge lamp has a structure as shown in a longitudinal section in FIG. 7A and a sectional view in FIG. 7B, respectively. That is, instead of sealing a pair of electrodes 3 and 3 'in a fluorescent discharge tube body 2 in which a phosphor coating 1 is formed on a light emitting surface of an inner wall of a glass tube and a rare gas containing xenon is sealed, the fluorescent discharge tube body is A pair of strip-shaped conductive coatings (external electrodes) 5, 5 'from one end side to the other end side
And an electrodeless xenon fluorescent discharge lamp in which a required discharge voltage is applied between the conductive films 5 and 5 '. The second xenon fluorescent discharge lamp has a structure as shown in a vertical section in FIG. 8A and a cross section in FIG. 8B. That is, the fluorescent film 1 is formed on the light emitting surface of the inner wall of the glass tube, and the electrode 3 is sealed in the fluorescent discharge tube main body 2 in which a rare gas containing xenon is sealed. This is a xenon fluorescent discharge lamp in which a semicircular conductive coating 5 is provided from one end to the other end, and a required discharge voltage is applied between the internal electrode 3 and the conductive coating 5.

[0007]

FIG. 7 (a) and FIG. 7 (b)
In the case of the electrodeless xenon fluorescent discharge lamp shown in FIG. 1, when a required discharge voltage is applied between the external electrodes 5 and 5 'to cause a discharge, the positive column directly hits the phosphor film 1, so that The luminous efficiency is improved as compared with the xenon fluorescent discharge lamp shown in FIG. However, when the diameter of the glass tube forming the fluorescent discharge tube main body 2 is small, it is difficult to sufficiently secure the insulation between the external electrodes 5 and 5 ′ disposed facing the outer peripheral surface. Atmospheric discharge may occur, leading to damage of the xenon fluorescent discharge lamp.

In the case of the xenon fluorescent discharge lamp shown in FIGS. 8A and 8B, a required discharge voltage is applied between the internal electrode 3 and the external electrode 5 to generate a discharge. ,
The emission luminance is improved. However, since the positive column shrinks in the region on the side of the internal electrode 3 and diffuses in other regions, the structure shown in FIG.
As schematically shown in FIG. 1, there is a problem that luminance unevenness easily occurs in the axial direction of the fluorescent discharge tube main body 2. In addition, the internal electrode 3
Since there is only one, the current is concentrated, and as a result, the life of the xenon fluorescent discharge lamp tends to be reduced.

The present invention has been made in view of the above circumstances, and provides a lighting method which is high in brightness and luminance, has improved luminance unevenness in a tube axis direction, and is suitable for a backlight function of display devices and the like. With the goal.

[0010]

According to the first aspect of the present invention, there is provided a fluorescent discharge tube main body in which a rare gas containing xenon gas is sealed and a phosphor film is provided on an inner wall surface, A pair of electrodes sealed opposite to both ends, a pair of lead wires electrically connected to the pair of electrodes and led out of the fluorescent discharge tube body in a gas-tight manner, one end on the outer peripheral surface of the fluorescent discharge tube body A method for lighting a xenon fluorescent discharge lamp having a conductive coating disposed in a band shape from the side to the other end, and a lead electrically connected to the conductive coating, wherein the xenon fluorescent lamp faces the inside of the fluorescent discharge tube body. A xenon fluorescent discharge lamp characterized in that a voltage capable of being discharged is applied between at least one of the electrodes and the conductive coating while a voltage is applied to the pair of sealed electrodes with a potential difference of 500 V or less. It is a lighting method. That is, in the present invention, when lighting the fluorescent discharge tube, a voltage that does not cause a discharge between the two electrodes is applied to the pair of sealed electrodes facing each other in the fluorescent discharge tube main body, and at least one of these two electrodes is applied. One of the electrodes,
The main point is to apply a required dischargeable voltage to a conductive coating (external electrode) integrally provided on the outer peripheral surface of the fluorescent discharge tube body to perform discharge and light emission.

According to the present invention, a rare gas containing a xenon gas is sealed, and a pair of electrodes are sealed opposite to both ends. The present invention is based on findings from various attempts at lighting a xenon fluorescent discharge lamp having a configuration in which a conductive coating is disposed as an external electrode. That is, in lighting the xenon fluorescent discharge lamp, while applying a voltage having a potential difference of 500 V or less between the pair of sealed electrodes, a required voltage is applied between at least one of the pair of sealed electrodes and the external electrode. The lighting operation was performed by applying the discharge voltage of. As a result, the influence on the brightness and brightness of the outside air temperature is reduced, and the brightness of the light emitting portion is effectively increased.
It has been confirmed that the lighting life is prolonged and the luminance unevenness in the tube axis direction is also improved, and the present invention has been achieved.

According to the present invention, the sealing of the rare gas containing xenon not only eliminates the decrease in brightness in the low-temperature region but also discharges between the external electrode and the internal electrode. The contact between the external electrode and the internal electrode improves the luminous efficiency, reduces the luminance unevenness, and, in the discharge between the external electrode and the internal electrode, current does not concentrate on one of the internal electrodes. The reduction in life due to wear is also eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, FIGS. 1 (a) to 1 (c) and 2 (a)
An embodiment will be described with reference to FIGS. 3, 4 and 5.

FIGS. 1A and 1B show the main components of a xenon fluorescent discharge lamp according to an embodiment. FIG. 1A is a longitudinal sectional view, and FIGS. 1B and 1C are different transverse sectional views. 1 (a) to 1 (c), reference numeral 2 denotes a fluorescent discharge tube main body in which a rare gas containing xenon gas is sealed and a phosphor film 1 is provided on an inner wall surface;
Reference numerals 3, 3 'denote a pair of electrodes which are sealed opposite to both ends in the fluorescent discharge tube main body 1. Here, the fluorescent discharge tube body 1 has a wall thickness of about 0.32 mm, an outer diameter of about 2.5 mm, and a length between the sealing ends of about 200 mm. It is sealed inside the edge. The rare gas containing the xenon gas sealed in the fluorescent discharge tube main body 2 is generally a mixed system of xenon and another rare gas.

Further, reference numerals 4 and 4 'denote the pair of electrodes 3,
3 ', one end of which is electrically connected to each other, and the other end is a pair of lead-in wires hermetically drawn out of the fluorescent discharge tube main body 1, and 5 is connected to the outer peripheral surface of the fluorescent discharge tube main body 1 from one end to the other end. A conductive coating 6 serving as an external electrode disposed in a strip shape on the side is a lead electrically connected to the conductive coating 5. here,
The conductive film 5 is, for example, a vapor-deposited film of aluminum or the like, and is provided so as to straddle the electrodes 3 and 3 ′. Is also set small. The phosphor layer may be the entire circumference of the inner wall of the fluorescent discharge tube main body 1, or may be a semicircle.

Next, a lighting method of the xenon fluorescent discharge lamp will be described. FIGS. 2A to 2C are circuits showing embodiments of different lighting methods. First, Fig. 2 (a)
Applies two voltages between the external electrode 5 and the internal electrode 3 and between the external electrode 5 and the internal electrode 3 ′ using two lighting power sources 8 a and 8 b in order to light the xenon fluorescent discharge lamp 7. I have. At this time, as for the phase difference and output value of the voltage outputted from the power supplies 8a and 8b, the potential difference between the internal electrodes 3 and 3 'is always set to 0 to 500V.

Next, FIG. 2B shows a xenon fluorescent discharge lamp 7.
In order to reduce the potential between the internal electrodes 3 and 3 'to 0 V, one output terminal of one lighting power supply 8 is connected to the internal electrodes 3 and 3', and the other output terminal is connected to the external electrode 5. ing.

Further, FIG. 2 (c) is the same as FIG. 2 (a), (b)
Is basically the same as the circuit of FIG.
Between the internal electrodes 3, 3 'and the power supply 8,
9b is inserted. 2A and 2B, currents of positive and negative polarities flow into the internal electrodes 3 and 3 '. On the other hand, in the case of the system shown in FIG. 2C, the polarity of the current flowing into the internal electrodes 3 and 3 'is separated by the inserted diodes 9a and 9b. Only the negative current flows into the internal electrode 3. By the way, luminance unevenness has a characteristic that it is more likely to occur as the current is larger.
(c) In the case of the system shown in the figure, the current polarity is separated by the diodes 9a and 9b, and the current flowing into the internal electrodes 3 and 3 'can be made smaller. The brightness unevenness can be improved as compared with the case of the method.

FIG. 3 shows a luminance (cd / m ² ) distribution in the tube axis direction when the xenon fluorescent discharge lamp 7 is operated by the above-mentioned lighting method (method). It was confirmed that the brightness was almost constant over the entire length and uniform light distribution was obtained. In addition, the relationship between the lighting frequency (kHz) in the above-mentioned lighting operation and the ratio (%) of the uniform light emitting region to the entire length of the lamp was tested and evaluated. For comparison,
FIG. 4 also shows the relationship between the lighting frequency (kHz) and the ratio (%) of the uniform light emitting region to the entire length of the lamp when the xenon fluorescent discharge lamp having the structure shown in FIG. As can be seen from the characteristic diagram of FIG. 4, in the case of the example, the uniform light emitting area is enlarged, the area where the luminance unevenness occurs is reduced, and more stable light emission is obtained as compared with the comparative example. Is shown.

Further, in the above lighting operation, the relationship between the input (W) of the xenon fluorescent discharge lamp 7 (W) and the total luminous flux (Lm) was tested and evaluated. The result was as shown by a curve B in FIG. For comparison, the relationship between the xenon fluorescent lamp input (W) and the total luminous flux (Lm) when the xenon fluorescent lamp having the configuration shown in FIG. . As can be seen from the characteristic diagram of FIG. 5, in the case of the embodiment, the brightness is greatly improved with respect to the input.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the thickness, outer diameter, overall length, and the like of the glass tube forming the xenon fluorescent discharge tube main body can be arbitrarily selected and set according to the application. In addition to xenon, noble gases to be sealed include krypton, argon,
Neon, helium, or the like may be used.

[0022]

As can be seen from the comparison of the above embodiments, according to the method of lighting a xenon fluorescent discharge lamp according to the present invention, not only can a substantially constant light output be obtained irrespective of the ambient temperature, but also a conventional internal electrode can be obtained. The luminance is also improved to about 2 to 3 times as compared with the case of discharge lighting during the period. In addition, as both internal electrodes are used for required discharge, the life of the electrodes is extended, and the region where luminance unevenness occurs in the tube axis direction is narrowed. Therefore, a lighting method suitable for a backlight function of a display device or the like is provided in combination with high brightness and luminance and a long life.

[Brief description of the drawings]

FIG. 1 shows a main part configuration of a xenon fluorescent discharge lamp used in an embodiment, in which (a) is a longitudinal sectional view, (b) and (c) are different transverse sectional views.

2 (a), 2 (b) and 2 (c) are circuit diagrams showing different lighting embodiments of a xenon fluorescent discharge lamp.

FIG. 3 is a characteristic diagram showing an example of the relationship between the discharge lamp length direction and luminance when the xenon fluorescent discharge lamp is turned on.

FIG. 4 is a characteristic diagram showing an example of a relationship between a lighting frequency and a luminance unevenness occurrence rate in lighting of a xenon fluorescent discharge lamp in comparison with a case of a conventional lighting method.

FIG. 5 is a characteristic diagram showing an example of a relationship between a lighting input and a total luminous flux in lighting of a xenon fluorescent discharge lamp in comparison with a conventional lighting method.

6A and 6B show a first main configuration of a conventional xenon fluorescent discharge lamp, in which FIG. 6A is a longitudinal sectional view, and FIG. 6B is a transverse sectional view.

7A and 7B show a second main configuration of a conventional xenon fluorescent discharge lamp, wherein FIG. 7A is a longitudinal sectional view, and FIG. 7B is a transverse sectional view.

FIGS. 8A and 8B show a third essential configuration of a conventional xenon fluorescent discharge lamp, in which FIG. 8A is a longitudinal sectional view and FIG. 8B is a transverse sectional view.

9 is a characteristic diagram showing an example of the relationship between the discharge lamp length direction and luminance in the lighting shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Phosphor film 2 ... Discharge tube main body 3,3 '... Internal electrode 4,4' ... Introduction line 5,5 '... Conductive film (external electrode) 6 ... Lead 7 ... Xenon fluorescence Discharge lamp 8 Lighting power supply 9a, 9b Diode

Claims (1)

[Claims] 1. A rare gas containing xenon gas is sealed,
A fluorescent discharge tube body having a phosphor film provided on an inner wall surface, a pair of electrodes sealed opposite to both ends in the fluorescent discharge tube body, and a fluorescent discharge electrically connected to the pair of electrodes, respectively. A pair of lead-ins that are airtightly led out of the pipe body,
A method of lighting a xenon fluorescent discharge lamp having a conductive coating disposed in a band shape from one end side to the other end side on the outer peripheral surface of the fluorescent discharge tube body, and a lead electrically connected to the conductive coating, Applying a voltage with a potential difference of 500 V or less to a pair of electrodes opposed to each other and sealed in the fluorescent discharge tube body, and applying a dischargeable voltage between at least one of the electrodes and the conductive coating. Characteristic lighting method of xenon fluorescent discharge lamp.