JP2007073254A - External electrode discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily manufacturable and inexpensive external electrode discharge lamp with a simplified discharge lamp structure that achieves a longer service lifetime while eliminating consumption of mercury or the like of a discharge gas and electrodes 3, 4, by the arrangement of the elongated electrodes 3, 4 to the outside of a discharge tube 2 and a discharge panel 6. <P>SOLUTION: One or two or more elongated electrodes 3 connected to one terminal of an AC power supply 5 and one or two or more elongated electrodes 4 connected to the other terminal of the AC power supply 5 are arranged along in the tube-axis direction, on the external face of the discharge tube 2 internally sealed with a low-pressure discharge gas and having a longer tube-length. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an external electrode discharge lamp in which an electrode is formed outside rather than inside a discharge body such as a discharge tube or a discharge panel.

  A cold cathode tube used as a backlight of a liquid crystal display has an electrode (a filament in the case of a fluorescent lamp) arranged inside a discharge tube, like a fluorescent lamp for illumination. In this discharge tube, a low-pressure discharge gas composed of, for example, argon gas and mercury vapor is sealed in an elongated straight tube-shaped glass tube whose inner wall surface is coated with a phosphor, and both ends are sealed. In addition, the electrodes are respectively disposed at both ends of the inside of the glass tube, and only the lead material is sealed and drawn out to the outside when the both ends of the glass tube are sealed.

Here, the light emission principle of the cold cathode tube will be described with reference to FIG. The cold cathode tube shown in FIG. 1 is shown with the tube diameter deformed wider than the actual tube length to make the drawing easier to see. In this cold cathode tube, when a high voltage is applied to the electrodes 1a and 1b disposed at both ends inside the discharge tube 1, an electric field E is generated and electrons e existing in the tube are accelerated, and the arrow (1) As shown, it collides with mercury atom Hg. Then, the mercury atom Hg absorbs the kinetic energy of the colliding electron e and emits the outermost electron e as shown by the arrow (2). It becomes ion Hg ⁺ . Moreover, since the electron e generates a new electron e every time it collides with the mercury atom Hg, the number rapidly increases due to the avalanche of electrons. Further, the mercury ion Hg ⁺ thus excited is recombined with the electron e according to a constant time constant as shown by the arrow (4), and then returns to the mercury atom Hg in the ground state. As shown in (5), the energy at this time is emitted as ultraviolet rays having a wavelength of 245 nm. The ultraviolet rays emitted from the mercury atoms Hg are converted into visible light by the phosphor layer 1c formed on the inner wall surface of the discharge tube 1, and are emitted to the outside as indicated by the arrow (6).

However, as described above, when the electrodes 1a and 1b are present inside the discharge tube 1, the mercury ions Hg ⁺ and argon ions ionized in the discharge plasma become the negative electrodes 1a and 1b as shown by the arrow (7). (FIG. 1 shows an example of collision with the electrode 1b), the metal material of these electrodes 1a and 1b is sputtered and the metal M is released. And since this metal M couple | bonds with mercury atom Hg and produces | generates an amalgam, the metal material and mercury atom Hg of these electrodes 1a and 1b will be consumed gradually with progress of lighting time. In particular, in a cold cathode tube, since it is necessary to apply a high voltage of 1000 V or more at the start of lighting, the sputtering effect at the electrodes 1a and 1b becomes intense, and the consumption of mercury atoms Hg and the like becomes very significant. Therefore, in the discharge tube 1 in which the electrodes 1a and 1b are provided inside, the consumption of mercury atoms Hg and the like due to the sputtering effect at the electrodes 1a and 1b has become a main factor limiting the lamp life.

  Thus, various proposals have been made for external electrode discharge lamps (sometimes referred to as “electrodeless discharge lamps” or the like) in which no electrode is formed inside the discharge tube. This external electrode discharge lamp generates an electric field inside the discharge tube from the outside to accelerate the electrons in the tube, and light emission occurs when the accelerated electrons collide with mercury atoms. Is called.

However, most of the conventional external electrode discharge lamps are of an inductive coupling type that induces an electric field inside the discharge tube by the magnetic flux generated by the coil (see, for example, Patent Document 1). Therefore, the structure of the discharge lamp is complicated and expensive. In addition, the size of the discharge lamp is increased by the amount of the coil provided outside, so that a large installation space is required, or a large number of discharge lamps are closely approached, such as when used as a backlight for a liquid crystal display. There was also a problem that it could not be placed.
JP 11-191398 A

  According to the present invention, by disposing elongated electrodes outside the discharge body, it is possible to extend the life by eliminating the discharge gas mercury and the like and the consumption of the electrodes, simplify the structure of the discharge lamp, and facilitate manufacture. An object of the present invention is to provide a low-cost external electrode discharge lamp.

  The external electrode discharge lamp according to claim 1 is one or two connected to one terminal of an AC power supply along the tube axis direction on the outer surface of a long tube having a low-pressure discharge gas sealed therein. One or more elongated electrodes and one or more elongated electrodes connected to the other terminal of the AC power supply are arranged.

  The external electrode discharge lamp according to claim 2 is a plurality of external electrode discharge lamps connected to one terminal of an AC power supply on the outer surface of one flat wall of a discharge panel in which a space between upper and lower flat walls is sealed and a low-pressure discharge gas is sealed inside. And a plurality of elongated electrodes connected to the other terminal of the AC power supply are alternately arranged one by one.

  The external electrode discharge lamp according to claim 3 has a plurality of elongated electrodes connected to one end of the AC power supply and a plurality of elongated electrodes connected to the other end of the AC power supply alternately on the upper surface of the insulating substrate. A discharge body in which a low-pressure discharge gas is sealed is disposed above the insulating substrate.

  The external electrode discharge lamp according to claim 4 is a straight tube type discharge tube in which the discharge tube according to claim 1 or the discharge body according to claim 3 encloses a low-pressure discharge gas inside a straight tube and seals both ends. It is characterized by being.

  According to a fifth aspect of the present invention, in the external electrode discharge lamp, the discharge panel of the second aspect or the discharge body of the third aspect has two glass substrates arranged at intervals in the vertical direction and a low pressure between these glass substrates. The discharge panel is characterized in that the discharge gas is sealed and the peripheral edge is sealed.

  Note that the vertical direction in the present application is merely for the convenience of showing directions opposite to each other, and actually, the vertical direction may be reversed, or may be directed in the left-right direction or the front-rear direction.

  According to the first aspect of the present invention, when an AC power supply voltage is applied between the electrodes disposed on the outer surface of the discharge tube, an electric field is generated inside the discharge tube. The metal atoms in the discharge gas are excited by the collision and can emit light. Moreover, since the polarity of the voltage of the AC power supply is repeatedly switched, electrons in the discharge tube reciprocate, and light emission can be continued. Moreover, since the distance between electrodes of different polarities can be as short as the tube diameter of the discharge tube at the maximum, discharge can be started and maintained at a very low voltage, and the longitudinal direction inside the discharge tube can be maintained. The whole can emit light with almost no unevenness. Furthermore, since there are no electrodes inside the discharge tube, the life of the discharge lamp can be extended.

  According to the second aspect of the present invention, when an AC power supply voltage is applied between the electrodes disposed on the outer surface of one flat wall of the discharge panel, an electric field is generated inside the discharge panel. The metal atoms in the discharge gas are excited by the collision of electrons and can emit light. In addition, since the polarity of the voltage of the AC power supply is repeatedly switched, electrons in the discharge panel reciprocate, and light emission can be continued. Moreover, since the distance between the alternately arranged electrodes can be made sufficiently short, the discharge can be started and maintained at an extremely low voltage, and the entire inside of the discharge panel can be made to emit light almost uniformly. become. Furthermore, since the electrodes are disposed only on one outer surface of the discharge panel, the manufacture and assembly of the discharge lamp can be facilitated. Furthermore, since there are no electrodes inside the discharge panel, the life of the discharge lamp can be extended.

  According to the invention of claim 3, when the voltage of the AC power supply is applied between the electrodes alternately disposed on the insulating substrate, an electric field is generated inside the discharge body disposed above the insulating substrate. Due to the collision of electrons accelerated by this electric field, the metal atoms in the discharge gas are excited to emit light. Moreover, since the polarity of the voltage of the AC power source is repeatedly switched, electrons in the discharge body reciprocate, and light emission can be continued. Moreover, since the distance between the alternately arranged electrodes can be made sufficiently short, the discharge can be started and maintained at an extremely low voltage, and the entire inside of the discharge body can be made to emit light almost uniformly. become. Furthermore, the insulating substrate on which the discharge body and the electrode are arranged can be separately manufactured, and the discharge lamp can be easily manufactured and assembled. Furthermore, since there are no electrodes inside the discharge body, the life of the discharge lamp can be extended.

  According to invention of Claim 4, since a straight tube type discharge tube can be used, this discharge tube can be manufactured at low cost. Moreover, not only is the manufacturing cost cheaper than when a U-tube type discharge tube is used, but when the phosphor layer is formed on the inner wall surface of the discharge tube, the fluorescent pair layer is damaged during bending. Therefore, the life of the discharge tube can be extended.

  According to the invention of claim 5, the discharge panel can be easily manufactured by using two glass substrates.

  Hereinafter, the best embodiment of the present invention will be described with reference to FIGS.

  In the present invention, a plurality of elongated electrodes connected to an AC power source are arranged outside the discharge body, and light is emitted by an electric field generated between these electrodes inside the discharge body. As the discharge body, for example, a discharge tube of a straight tube type, a discharge panel in which the periphery of two glass substrates with a space between them is sealed, or the like can be used. In the following embodiments, the electrode is disposed directly on the outer surface of the discharge body (first embodiment and second embodiment), and the electrode is disposed on an insulating substrate outside the discharge body (third embodiment). ).

  In the following embodiments, the case where argon gas and mercury vapor are used as the discharge gas sealed inside the discharge body (discharge tube, discharge panel, etc.) is shown. This discharge gas is composed of rare gas and metal vapor. Other combinations can be used as long as they are mixed gas. Further, in the following embodiment, since an external electrode discharge lamp used for illumination or as a backlight will be described, a case where a phosphor layer is formed on the inner wall surface of a discharge body is shown, but when used as an ultraviolet lamp or the like, Such a phosphor layer need not be formed. Furthermore, in the following embodiment, the case where the discharge body is made of glass is shown. However, the material is not limited to glass as long as it is a material that can transmit emitted light (not necessarily visible light) and seal discharge gas. For example, quartz glass can be used.

  Moreover, although the following embodiment shows the case where an inverter that converts a DC power source (often rectified from a commercial AC power source) into an AC is used as the AC power source, an AC voltage is applied between the electrodes. The configuration of the power supply is arbitrary as long as it can supply a current due to discharge. Furthermore, the frequency of the AC power supply can be arbitrarily changed according to the characteristics of the external electrode discharge lamp.

[First Embodiment]
In the present embodiment, as shown in FIG. 2, an external electrode discharge lamp (corresponding to claim 1) in which electrodes 3 and 4 are directly formed on the outer surface of the discharge tube 2 will be described. The discharge tube 2 is formed by enclosing a discharge gas composed of low-pressure argon gas and mercury vapor in an elongated straight cylindrical glass tube having a tube diameter of 2.5 mm and sealing both ends. A phosphor layer 2 a is formed on the inner wall surface of the discharge tube 2.

  In the discharge tube 2, straight and elongated electrodes 3 and 4 are arranged at the upper and lower opposing positions on the outer side surface along the straight tube type tube axis direction, respectively. Each of these electrodes 3 and 4 is a copper wire having a wire diameter of 0.06 mm, and is fixed to the glass wall on the outer surface of the discharge tube 2 with an adhesive or the like. One electrode 3 is connected to one terminal of the AC power supply 5, and the other electrode 4 is connected to the other terminal of the AC power supply 5. The AC power source 5 uses an inverter that supplies AC power of 40 kHz.

  When the AC voltage supplied from the AC power supply 5 is applied between the electrodes 3 and 4, the external electrode discharge lamp having the above configuration has a direction inside the discharge tube 2 as indicated by an arrow in FIG. An electric field E that is alternately switched is generated. Then, as in the case of the cold cathode tube, electrons in the discharge tube 2 are alternately accelerated in the opposite direction by the electric field E, and light emission is started and maintained by exciting the mercury atoms one after another. In addition, since the electrodes 3 and 4 are outside the discharge tube 2 and are not present inside, the mercury in the discharge gas and the consumption of the electrodes 3 and 4 are eliminated, thereby extending the life of the discharge lamp. Can do.

  Moreover, since the distance between the electrodes 3 and 4 is only 2.5 mm, which is the tube diameter of the discharge tube 2, light emission can be started and maintained even when the AC power supply 5 is at a low voltage. Further, in the longitudinal direction of the discharge tube 2, the whole can start emitting light almost simultaneously without distinction of both end portions and the central portion, and light can be emitted almost uniformly.

  By the way, when considering an electrostatic coupling type external electrode discharge lamp in which electrodes are formed on both outer surfaces in the longitudinal direction of a long discharge tube 2 and a voltage from an AC power source 5 is applied, the distance between the electrodes is the conventional distance. Since it is slightly longer than the cold cathode tube and a dielectric made of the glass wall of the discharge tube 2 is interposed, it is necessary to apply a higher voltage (for example, 1000 V or more) than this cold cathode tube. In addition, light emission is started from both ends of the discharge tube 2 in the vicinity of the electrodes, and light emission is also started at the center portion by further increasing the voltage, so that uneven light emission tends to occur in the longitudinal direction of the discharge tube 2. Therefore, it is not easy to control the emission luminance.

  In the present embodiment, the case where copper wires are used as the electrodes 3 and 4 has been shown. However, as long as the conductive material is disposed on the outer surface of the discharge tube 2, the material of the wire is arbitrary, and the wire diameter is also limited. Not. Moreover, since these electrodes 3 and 4 should just be an electroconductive material, for example, a strip-shaped metal foil or the like is attached to the outer surface of the discharge tube 2, or as shown in FIG. The formed conductive film can also be used as the electrodes 3 and 4.

  Here, when the discharge tube 2 having a thin tube diameter as shown in FIG. 2 or FIG. 3A is used, the emission color may be reddish. In this case, if the discharge tube 2 having a large tube diameter as shown in FIG. 3B is used, the emission color can be made white. In the case of the discharge tube 2 having a small tube diameter, this is thought to be caused by the fact that the discharge space between the electrodes 3 and 4 becomes narrower than the mean free path of electrons, thereby increasing the wavelength of the emitted ultraviolet light. . Therefore, in the case of the discharge tube 2 having a small tube diameter, it may be possible to solve the problem by shortening the mean free path of electrons by increasing the argon gas concentration of the discharge gas in a range not causing arc discharge.

  On the other hand, in the discharge tube 2 having a large tube diameter shown in FIG. 3B, the discharge space between the electrodes 3 and 4 has a sufficient space. It can also be formed close to one side (upward in the figure) as shown in the figure, not at the position opposite to the outer surface. In the external electrode discharge lamp shown in FIG. 3A, since the electrodes 3 and 4 are conductive films wider than the copper wire, much of the emitted light emitted in the vertical direction is blocked, and this emitted light is It will be emitted mainly in the left-right direction. However, as shown in FIG. 3B, in the external electrode discharge lamp formed by bringing the electrodes 3 and 4 upward, most of the emitted light radiated upward is blocked, but a wide angle is formed downward. It becomes possible to emit emitted light in a range.

  In the present embodiment, the pair of electrodes 3 and 4 are arranged on the outer surface of the discharge tube 2. However, the electrode 3 connected to one terminal of the AC power supply 5 and the other terminal are connected. One electrode 4 is not necessarily arranged one by one, and two or more of either, or two or more of both can be arranged. For example, FIG. 4 shows an example in which two electrodes 3 and 3 connected to one terminal and one electrode 4 connected to the other terminal are arranged on the outer surface of the discharge tube 2. Thus, also when arranging a plurality of electrodes 3 and / or electrodes 4, it is preferable to arrange the electrodes 3 and 4 alternately one by one. However, in the example of FIG. 4, the electrodes 3 and 3 are alternately arranged with the electrodes 4 on the left half of the outer surface of the discharge tube 2 in the drawing, but in the right half of the drawing, the electrodes 3 and 3 are adjacent to each other with a wide space. A large amount of emitted light can be emitted from the right half periphery. In the case where a plurality of electrodes 3 and 4 are arranged over the entire circumference of the outer surface of the discharge tube 2, a part of or all of the electrodes 3 and 4 are made transparent electrodes such as ITO, so that the emitted light can be broadened. It will be possible to radiate outside.

  Further, in this embodiment, the case where the discharge tube 2 having a cylindrical cross section perpendicular to the tube axis is used, but this cross sectional shape is arbitrary, for example, an ellipse, an oval, or a rounded corner. The shape can be a square or the like. Further, in the present embodiment, the case where the straight tube type discharge tube 2 is used is shown. However, even in the case of a discharge tube such as a U-shaped tube or an L-shaped tube, the embodiment can be similarly implemented. 3, 4 are arranged in a curved shape along the bent tube axis direction.

[Second Embodiment]
In the present embodiment, as shown in FIG. 5, an external electrode discharge lamp (corresponding to claim 2) in which electrodes 3 and 4 are directly formed on the flat outer wall surface on the upper side of the discharge panel 6 will be described. In the discharge panel 6, two rectangular glass substrates 6a and 6b are arranged at an interval in the vertical direction, and a discharge gas composed of low-pressure argon gas and mercury vapor is sealed between the glass substrates 6a and 6b. The peripheral portion is sealed with a sealing material 6c. A phosphor layer 6d is formed on the inner wall surfaces of these glass substrates 6a and 6b. Accordingly, a flat outer wall surface formed of the upper surface of the glass substrate 6a is formed on the upper side of the discharge panel 6, and a flat outer wall surface formed of the lower surface of the glass substrate 6b is formed on the lower side. The sealing material 6c is not particularly limited as long as it can seal the discharge gas inside the discharge panel 6. For example, a material obtained by curing an epoxy resin or a material obtained by bonding a glass rib with an epoxy resin is used. be able to.

  The glass substrates 6a and 6b are both made of the same glass plate, but the upper glass substrate 6a forming the electrodes 3 and 4 should be as thin as possible in order to efficiently generate an electric field inside the discharge panel 6. Since it is good, in order to raise the intensity | strength of the discharge panel 6, the plate | board thickness of the lower glass substrate 6b is made thick. Further, when the glass substrate 6a is thinned in this manner, particularly when the area of the glass substrate 6a is large, the glass substrate 6a is easily damaged by an external force applied from outside. Therefore, it is preferable to sandwich a glass rod 6e, glass beads, or the like as shown in FIG. 6 between the glass substrates 6a and 6b. FIG. 6 shows a case where a plurality of glass rods 6e in a direction perpendicular to the longitudinal direction of these electrodes 3 and 4 are sandwiched so as not to interrupt a discharge generated between the electrodes 3 and 4.

  On the upper surface of the glass substrate 6a on the upper side of the discharge panel 6, a plurality of electrodes 3 and 4 are alternately arranged one by one. Each of these electrodes 3 and 4 is an elongated strip-like conductive film that is linear from the front side to the back side in FIG. 5, for example, a metal film is deposited on the upper surface of the glass substrate 6a, or a conductive paste is applied and fired. It is formed by doing. One electrode 3 is connected in common to one terminal of the AC power supply 5, and the other electrode 4 is connected in common to the other terminal of the AC power supply 5. However, since it is troublesome to connect the terminals of the AC power source 5 to the electrodes 3 and 4, respectively, actually, as shown in FIG. 6, each electrode 3 and each electrode 4 are respectively the upper surface of the glass substrate 6a. A pattern is formed in a SAW filter shape so as to be drawn from common common conductive portions 3 a and 4 a formed on both sides in the width direction, and these common conductive portions 3 a and 4 a are connected to terminals of the AC power supply 5. ing. The AC power source 5 uses an inverter that supplies a 40 kHz AC power source, as in the first embodiment.

  In the external electrode discharge lamp having the above-described configuration, when an AC voltage supplied from the AC power supply 5 is applied between the electrodes 3 and 4, an electric field whose direction is alternately switched is generated inside the discharge panel 6, and the first embodiment As in the case of the embodiment, the electrons are alternately accelerated in the opposite direction and the mercury atoms are excited one after another to start and maintain light emission. Further, since the electrodes 3 and 4 are outside the discharge panel 6 and are not present inside, the mercury in the discharge gas and the consumption of the electrodes 3 and 4 are eliminated, thereby extending the life of the discharge lamp. Can do.

  In addition, since the distance between the electrodes 3 and 4 can be arbitrarily shortened by forming a conductive film pattern, light emission can be started and maintained even when the voltage of the AC power supply 5 is low. In addition, by forming the pattern of the conductive film, light can be emitted almost uniformly over the entire surface of the discharge panel 6, and the light emission luminance can be easily controlled.

  By the way, when the electrode 3 is formed on the upper surface of the one glass substrate 6a and the electrode 4 is formed on the upper surface of the other glass substrate 6b, the counter electrode is formed through these glass substrates 6a and 6b. Since the electrodes 3 and 4 must be formed on both the glass substrates 6a and 6b, the manufacturing process becomes complicated, the handling in the assembly process becomes troublesome, and the cost increases. Further, since the electrode 4 is also formed on the lower glass substrate 6b, the glass substrate 6b cannot be thickened, and the strength of the discharge panel 6 is reduced. And cost increases. And since the discharge panel 6 needs to radiate | emit emitted light to the exterior from at least one glass substrate 6a or the glass substrate 6b, when transparent electrodes, such as expensive ITO, are used for one or both of the electrodes 3 and 4, Cost will rise further.

  In the present embodiment, a conductive film is formed as the electrodes 3 and 4. However, any conductive material disposed on the outer surface of the discharge panel 6 may be used. The metal foil or the like can be attached to the upper surface of the glass substrate 6a. Further, in the present embodiment, the case where the linear electrodes 3 and 4 are arranged has been shown. However, since the plurality of elongated electrodes 3 and 4 only need to be arranged alternately one by one, 4 may be curved or bent.

  In the present embodiment, the light emitted from the discharge panel 6 is mainly emitted downward from the lower glass substrate 6b. As shown in FIG. 7, a reflective film is formed on the lower surface of the glass substrate 6b. It is also possible to form 6f so as to emit only upward from the upper glass substrate 6a. In this case, if transparent electrodes, such as ITO, are used for the electrodes 3 and 4, emitted light can be radiated | emitted upwards without further waste. The reflection film 6f may be made of any material as long as it efficiently reflects emitted light (may be not only specular reflection but also irregular reflection), but does not affect the electric field generated between the electrodes 3 and 4. Further, it is preferable to use an insulator such as titanium oxide. Further, such a reflective film 6f can be formed so as to cover the upper surface of the upper glass substrate 6a together with the electrodes 3 and 4 in place of the glass substrate 6b.

  Further, in the present embodiment, the case where the discharge panel 6 is constituted by the two glass substrates 6a and 6b has been shown. However, if processing is possible, the glass is integrally processed to form a seamless rectangular flat surface. What was produced in the shape of a mold container can also be used. Further, the discharge panel 6 does not necessarily have a square shape, and a circular flat shape or a flat shape having another shape can also be used.

[Third Embodiment]
In this embodiment, as shown in FIG. 8, an external electrode discharge lamp (corresponding to claim 3) in which electrodes 3 and 4 are formed on an insulating substrate 7 outside the discharge tube 2 will be described. The discharge tube 2 (excluding the electrodes 3 and 4 on the outer surface) and the AC power source 5 are the same as those in the first embodiment.

  The insulating substrate 7 may be of any material and shape as long as it is an insulating material that supports the electrodes 3 and 4, but the upper surface needs to be shaped so that a plurality of discharge tubes 2 can be arranged side by side. In the form, a rectangular plate whose upper and lower surfaces are flat is used. On the upper surface of the insulating substrate 7, as shown in FIG. 9, a plurality of electrodes 3 and 4 are alternately arranged one by one. Each of these electrodes 3 and 4 is a linear strip-shaped conductive metal foil that is slightly shorter than the width of the insulating substrate 7, and one by one along the length direction of the insulating substrate 7. They are arranged side by side. One electrode 3 is connected in common to one terminal of the AC power supply 5, and the other electrode 4 is connected in common to the other terminal of the AC power supply 5. However, in this case as well, as in the second embodiment, each electrode 3 and each electrode 4 are drawn out from common common conductive portions 3a and 4a formed at both ends in the width direction of the upper surface of the insulating substrate 7, respectively. Thus, a pattern is formed in a SAW filter shape, and these common conductive portions 3 a and 4 a are connected to the terminals of the AC power supply 5. Such pattern formation of the electrodes 3 and 4 on the insulating substrate 7 can be very easily produced by using a printed circuit board.

  As shown in FIG. 8, a plurality of discharge tubes 2 are arranged and fixed on the upper surface of the insulating substrate 7 so that the longitudinal directions of the discharge tubes 2 are orthogonal to the electrodes 3 and 4 and arranged at equal intervals. That is, the electrodes 3 and 4 are arranged side by side in the length direction of the insulating substrate 7, whereas the discharge tube 2 is arranged side by side in the width direction of the insulating substrate 7. At this time, it is desirable that the electrodes 3 and 4 disposed on the upper surface of the insulating substrate 7 are disposed so as to abut or extremely approach the outer surface below the discharge tube 2.

  In the external electrode discharge lamp having the above-described configuration, when an AC voltage supplied from the AC power supply 5 is applied between the electrodes 3 and 4, an electric field whose direction is alternately switched is generated inside each discharge tube 2, and the first As in the case of the embodiment and the second embodiment, the electrons are alternately accelerated in the opposite direction, and the mercury atoms are excited one after another, so that light emission is started and maintained. In addition, since the electrodes 3 and 4 are outside the discharge tube 2 and are not present inside, the mercury in the discharge gas and the consumption of the electrodes 3 and 4 are eliminated, thereby extending the life of the discharge lamp. Can do.

  In addition, since the distance between the electrodes 3 and 4 can be arbitrarily shortened by forming a pattern on the insulating substrate 7, light emission can be started and maintained even when the voltage of the AC power supply 5 is low. Further, since a plurality of electrodes 3 and 4 are formed at equal intervals in the longitudinal direction of the discharge tube 2, light can be emitted almost uniformly throughout the longitudinal direction of the discharge tube 2, and the emission luminance can be easily controlled. It becomes.

  Also in the case of the present embodiment, the discharge tube 2 has an arbitrary cross-sectional shape as in the case of the first embodiment, and is not limited to a straight tube type. Moreover, although the case where the discharge tubes 2 are arranged in the direction orthogonal to the arrangement of the electrodes 3 and 4 has been described in the present embodiment, they can be arranged in parallel or in an oblique direction. When the discharge tubes 2 are arranged in parallel with the arrangement direction of the electrodes 3, 4, one discharge tube 2 is arranged between each of the electrodes 3, 4, and this electrode 3 is arranged inside each discharge tube 2. , 4 is preferably generated without waste.

  Further, in the present embodiment, the case where a conductive metal foil as in the case of a printed circuit board or the like is used as the electrodes 3 and 4 is shown, but any conductive material disposed on the upper surface of the insulating substrate 7 may be used. A wire rod such as a copper wire, an elongated strip-shaped metal plate or the like can be attached to the upper surface of the insulating substrate 7, and a conductive film formed by vapor deposition or firing can be used as the electrodes 3 and 4. Further, in the present embodiment, the case where the linear electrodes 3 and 4 are arranged has been shown. However, since the plurality of elongated electrodes 3 and 4 only need to be arranged alternately one by one, 4 may be curved or bent.

  Further, in the present embodiment, the case where the discharge tube 2 is arranged on the upper surface of the insulating substrate 7 on which the electrodes 3 and 4 are arranged is shown. However, for example, the discharge panel 6 as shown in the second embodiment may be arranged. it can. That is, instead of directly arranging the electrodes 3 and 4 on the outer surface of the flat wall of the discharge panel 6, the electrodes 3 and 4 are arranged on the upper surface of the insulating substrate 7 arranged so as to be in contact with or close to the outer surface of the flat wall. As in the case of the second embodiment, the discharge panel 6 can emit light. When such a discharge panel 6 is used, one discharge panel 6 having substantially the same size may be disposed above the insulating substrate 7, or a plurality of smaller discharge panels 6 may be disposed. Further, a plurality of small insulating substrates 7 may be arranged below one large discharge panel 6, and a plurality of discharge panels 6 are arranged above the plurality of insulating substrates 7 without corresponding one to one. You can also

It is a longitudinal cross-sectional front view for demonstrating the light emission principle of a cold cathode tube, showing a prior art example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a first embodiment of the present invention, where (a) is a perspective view of an external electrode discharge lamp, and (b) is a cross-sectional view of the external electrode discharge lamp. 1 shows a first embodiment of the present invention, in which (a) is a cross-sectional view of an external electrode discharge lamp using a discharge tube having a small tube diameter, and (b) is an external view using a discharge tube having a large tube diameter. It is a cross-sectional view of an electrode discharge lamp. 1 shows a first embodiment of the present invention, and is a cross-sectional view of an external electrode discharge lamp having two electrodes on one side. FIG. 2 is a cross-sectional view of an external electrode discharge lamp according to a second embodiment of the present invention. FIG. FIG. 4 is an exploded perspective view of a discharge panel of an external electrode discharge lamp, showing a second embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating another example of the external electrode discharge lamp according to the second embodiment of the present invention. 3 is a perspective view of an external electrode discharge lamp, showing a third embodiment of the present invention. FIG. FIG. 10 is a perspective view showing an insulating substrate of an external electrode discharge lamp and electrodes arranged on the upper surface thereof according to a third embodiment of the present invention.

Explanation of symbols

2 Discharge tube 3 Electrode 4 Electrode 5 AC power supply 6 Discharge panel 6a Glass substrate 6b Glass substrate 7 Insulating substrate

Claims (5)

  One or two or more elongated electrodes connected to one terminal of an AC power source along the tube axis direction on the outer surface of a long tube with a low-pressure discharge gas sealed therein, and the AC power source One or two or more elongated electrodes connected to the other terminal of the external electrode discharge lamp are arranged.   A plurality of elongated electrodes connected to one terminal of an AC power supply and an other surface of the AC power supply on the outer surface of one flat wall of a discharge panel sealed between upper and lower flat walls and filled with a low-pressure discharge gas inside An external electrode discharge lamp characterized in that a plurality of elongated electrodes connected to the terminals are alternately arranged one by one.   A plurality of elongate electrodes connected to one end of the AC power supply and a plurality of elongate electrodes connected to the other end of the AC power supply are alternately arranged on the upper surface of the insulating substrate one by one. An external electrode discharge lamp comprising a discharge body in which a low-pressure discharge gas is sealed.   The discharge tube according to claim 1 or the discharge body according to claim 3 is a straight tube type discharge tube in which a low-pressure discharge gas is sealed in a straight tube body and both ends are sealed. lamp.   The discharge panel according to claim 2 or the discharge body according to claim 3 arranges two glass substrates at intervals in the vertical direction and encloses a peripheral portion by enclosing a low-pressure discharge gas between these glass substrates. An external electrode discharge lamp, which is a sealed discharge panel.

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