JP2000106144A - Internal and external electrode type discharge lamps and lighting devices - Google Patents

Abstract

(57) Abstract: Provided are an inner and outer electrode type discharge lamp in which discharge is stable and discharge flicker is unlikely to occur, and a lighting device using the same. A transparent medium containing a rare gas as a main component is enclosed in a light-transmitting discharge vessel, and an external electrode disposed on an outer surface of the light-transmitting discharge vessel and a longitudinal direction in the light-transmitting discharge vessel. And a pair of electrodes composed of internal electrodes that are extended and sealed, and at least the internal electrodes are provided with electric field concentration means dispersed in the longitudinal direction. Since the discharge current flows in and out of the electric field concentration means, the discharge is fixed and the flicker of the discharge is reduced. As the electric field concentrating means in the internal electrode, a projection can be provided on the electrode axis, or a concave portion can be formed on the electrode axis. As the electric field concentration means in the external electrode, a hole formed along a direction intersecting the longitudinal direction of the translucent discharge vessel can be formed. Also, when the electric field concentrating means are dispersed at intervals smaller than the distance between the electrodes,
The flicker of discharge is further suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal / external electrode type discharge lamp using a rare gas as a main discharge medium, and a lighting device using the same.

[0002]

2. Description of the Related Art A discharge lamp in which a rare gas such as xenon is sealed as a discharge medium in a translucent discharge vessel does not require the use of mercury, which has a large environmental load, and has a good luminous flux rising characteristic at low temperatures. Attention is paid to the advantage that However, a discharge lamp of an internal electrode type in which a rare gas is sealed in a structure in which a pair of electrodes are sealed inside both ends of a translucent discharge vessel emits a small amount of light.

[0003] Therefore, by forming a pair of electrodes in the form of external electrodes spaced apart along the longitudinal direction of the outer surface of the translucent discharge vessel, the amount of light emission can be increased. It has come to be. However, this external electrode type discharge lamp has disadvantages in that it emits a lot of electromagnetic noise and it is difficult to insulate the electrodes.

Further, there has been proposed an inner / outer electrode type discharge lamp in which one electrode is an external electrode and the other electrode is an internal electrode extending in the longitudinal direction of the translucent discharge vessel inside the translucent discharge vessel. . In this discharge lamp, the radiation noise can be reduced and the insulation between the electrodes is easy by lighting when the external electrodes are grounded.

FIG. 14 is a cross-sectional view showing a conventional inner and outer electrode type discharge lamp.

[0006] In the figure, 101 is a translucent discharge vessel, 1
02 is a phosphor layer, 103 is an aperture, 104 is an internal electrode, and 105 is an external electrode.

The translucent discharge vessel 101 is elongated and airtight, and has a discharge medium mainly containing a rare gas sealed therein.

The phosphor layer 102 is made of a light-transmitting discharge vessel 101.
It is formed substantially entirely on the inner surface side except for a slit-like portion along the longitudinal direction.

The aperture 103 is formed by a slit-shaped portion where the phosphor layer 102 is not formed.

The internal electrode 104 is made of a rod-shaped conductor.
The light-transmitting discharge vessel 101 extends substantially on the central axis inside the light-transmitting discharge vessel 101 and is sealed on both end faces of the light-transmitting discharge vessel 101.

The external electrode 105 is made of a metal foil, and is adhered to the outer surface of the translucent discharge vessel 101 except for the aperture 103.

When a required voltage is applied between the internal electrode and the external electrode, an ozonizer discharge of a rare gas is generated between the two electrodes, and ultraviolet rays are emitted. The irradiation of the ultraviolet light excites the phosphor of the phosphor layer 102 to generate visible light, and is concentrated and led out of the aperture 103 to the outside.

The above-described inner / outer electrode type discharge lamp is used for reading, for example, because visible light is intensively led out of the aperture 103.

[0014]

However, the conventional internal / external electrode type discharge lamp has a problem that flickering of the discharge occurs, which causes flickering of the brightness.

FIG. 15 is a partially enlarged light output waveform diagram for explaining the flickering of discharge in a conventional internal / external electrode type discharge lamp.

In the figure, the horizontal axis represents time, and the vertical axis represents light output (arbitrary value).

The flicker of discharge is indicated by the ratio (%) of the difference between the peak value and the valley value with respect to the average value of the light output.

As shown in the enlarged portion of the figure, when the flickering of the discharge occurs, the difference between the peak value and the valley value of the light output increases.

The flickering of the discharge in the internal and external electrode type discharge lamp occurs because the place where the whisker-like ozonizer discharge occurs between the internal and external electrodes moves with time. The flicker of brightness based on the flicker of the discharge is hardly perceived by human eyes because of the high repetition frequency. However, in the case of image reading or the like, it affects the definition of reading. It is necessary to reduce it to a degree that is not a problem.

An object of the present invention is to provide an inner / outer electrode type discharge lamp in which discharge is stable and discharge does not easily flicker, and an illuminating device using the same.

[0021]

According to the first aspect of the present invention, there is provided an inner / outer electrode type discharge lamp comprising: an elongated translucent discharge vessel; a discharge medium mainly containing a rare gas sealed in the translucent discharge vessel;
One is an external electrode disposed on the outer surface of the light-transmitting discharge vessel so as to generate a discharge inside the light-transmitting discharge vessel, and the other is extended and sealed in the light-transmitting discharge vessel in the longitudinal direction. And a pair of electrodes provided at least on the internal electrode with electric field concentrating means dispersed along the longitudinal direction thereof.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

(Translucent Discharge Vessel) The elongated translucent discharge vessel is preferably formed by sealing both ends of a glass bulb, but may be formed of a translucent ceramic if necessary. Good. Note that as the glass, soft glass, semi-hard glass, hard glass, quartz glass, or the like can be appropriately selected and used.

The fact that the discharge vessel is translucent does not require that the entire discharge vessel be translucent, but at least the portion that attempts to extract light generated by the discharge is translucent. Should be fine.

The expression that the light-transmitting discharge vessel is elongated means that it has a length that is at least twice the diameter of the discharge vessel.

The light-transmitting discharge vessel may be either a straight tube or a curved tube. As the curved tube, various shapes such as a U-shape, an annular shape, and a semi-annular shape can be adopted.

Further, in the present invention, the translucent discharge vessel may have a flat cross section. In this case, however, the distance from the center to the outer surface portion facing the external electrode is doubled to reduce the outer diameter. And

(Discharge Medium) The discharge medium is mainly composed of a rare gas, and the rare gas is allowed to be xenon, neon, argon, krypton, or the like. Further, in addition to the rare gas, a halide or a simple halogen of the rare gas may be added. As the halogen, iodine, bromine, and chlorine can be used. If the element exists as vapor in the range of several mmHg to several atmospheres, discharge is possible.

When the rare gas generates ultraviolet rays by electric discharge like xenon, a phosphor layer which is excited by the ultraviolet rays and generates visible light can be provided on the inner surface side of the translucent discharge vessel.

Further, the charging pressure of the discharge medium is set to 20 to 60 kP.
The luminous efficiency can be increased by defining a. However, if the filling pressure exceeds 60 kPa, the flickering of the discharge becomes remarkable, so it should be avoided.

(About a pair of electrodes) One of the pair of electrodes is constituted by an internal electrode.

The other electrode is constituted by an internal electrode.

The internal electrode may be in the form of a rod, a plate or a line over substantially the entire length of the light-transmitting discharge vessel in the longitudinal direction. Further, the internal electrodes may be sealed at one end of the translucent discharge vessel, or may be sealed at both ends.

Incidentally, as a characteristic configuration of the present invention, at least the internal electrodes are provided with electric field concentration means dispersed along the longitudinal direction.

Here, "electric field concentrating means" refers to a state in which the potential gradient around the electric field concentrating means is larger than in other parts, and therefore the electric field is concentrated around the electric field concentrating means. Means for producing.

The internal electrode can be realized by forming a projection on the electrode or forming a concave portion on the contrary.

The protrusions can be formed integrally by molding the electrodes by casting or the like, or can be separately prepared and fixed by using fixing means such as welding.

The concave portion can be formed by deforming the electrode by press molding or the like.

It is more effective to arrange the electric field concentration means on the external electrodes in addition to the internal electrodes. The electric field concentration means in the external electrode can be provided by forming slits or the like dispersed in the longitudinal direction.

By the way, that the electric field concentrating means are dispersed means that a large number of electric field concentrating means are arranged at appropriate intervals along the longitudinal direction of the translucent discharge vessel. The appropriate intervals are preferably the same pitch, but if necessary, the pitch may vary along the longitudinal direction of the translucent discharge vessel.

However, it is preferable to make the interval of dispersion of the step concentration means as small as possible in order to more effectively prevent flickering of discharge.

The other electrode is constituted by an external electrode provided on the outer surface of the translucent discharge vessel.

The external electrode has a planar spread along the outer surface of the translucent discharge vessel. As the external electrode, a metal foil such as aluminum, a conductive paint film, a metal deposition film, a transparent conductive film, a relatively thin metal plate, or the like can be appropriately used.

(Other Configurations) When it is desired to intensively emit light in a specific direction of the translucent discharge vessel,
It is effective to form a light-guiding slit called an aperture along the longitudinal direction of the translucent discharge vessel, and to form a reflective film on a portion other than the aperture. The reflective film can be formed on the inner surface of the light-transmitting discharge vessel by fine particles of titanium oxide or the like having high reflectance.

When the phosphor layer is formed on the inner surface side of the translucent discharge vessel, the phosphor layer may be formed in any one of a so-called aperture type not formed in the aperture portion and a reflection type formed in the aperture portion. Good. In the case of the aperture type, the reflection surface can be omitted.

Further, a protective film made of alumina fine particles or the like can be formed on the inner surface of the translucent discharge vessel. When forming a protective film, the phosphor layer is formed on the inner surface of the protective film.

(Regarding the operation of the present invention) The inner / outer electrode type discharge lamp as in the present invention has a relatively high voltage between the outer electrode and the inner electrode. Ozonizer discharge is generated in the translucent discharge vessel by applying the voltage in series. Then, ultraviolet rays are generated by the rare gas ozonizer discharge,
The ultraviolet light excites the phosphor to emit visible light. Also, in the ozonizer discharge, a streamer-type discharge is generated for each minute area in the gap with a dielectric interposed therebetween, and it is considered that the inside of the streamer is uniformly ionized from the cathode to the anode.

In the case where xenon is used as the discharge medium, xenon emits atomic light (Xe:
Molecular emission (Xe2: wavelength 152 nm, 172n) at a pressure of about 10 kPa or more.
m) increases.

Then, the capacitance C using the translucent discharge vessel as a dielectric becomes 1 / (2πfC) at the time of the ozonizer discharge.
And acts as a current-limiting impedance to form a constant current circuit, which suppresses the transition of the ozonizer discharge to the arc discharge and causes the entire discharge container to discharge.

However, in the present invention, since the electric field concentrating means are arranged in the internal electrodes dispersed along the longitudinal direction, the discharge current is concentrated on each electric field concentrating means and flows into and out of the internal electrodes. I do. In other words, at the time of a cathode cycle or a negative pulse application in which the internal electrode becomes a cathode, a discharge current flows from the electric field concentrating means toward the external electrode, so that the place where the discharge occurs is fixed.

Also, even when an anode cycle or a positive pulse is applied in which the internal electrode becomes an anode, the discharge current tends to concentrate and flow into the electric field concentration means in which the electric field concentrates basically similarly to the cathode cycle. , The location where the discharge occurs is fixed.

Therefore, the flicker of the discharge hardly occurs.

Next, the manner in which the above-described inner and outer electrode discharge lamps are lit at a high frequency will be described.

The output voltage waveform of the high-frequency power supply may be any of a sine wave AC, an asymmetric AC in which a DC is superimposed on a sine wave AC, and a pulse. Further, a half-wave rectified waveform of a sine wave alternating current may be used instead of the pulse. In the present invention, the high frequency refers to a frequency of 1 kHz or more or a repetition frequency. Actually, a range of 4 kHz to 1 MHz can be used, but a frequency of 100 kHz or more is effective for suppressing flickering of discharge.

When the inner and outer electrode type discharge lamps are lit by an asymmetric waveform voltage on which direct current is superimposed, the luminous efficiency is improved and a large amount of light can be obtained by lighting with a symmetric waveform voltage.

Further, in the case of pulse lighting or lighting using a voltage having a half-wave rectified waveform of a sine wave AC, afterglow occurs during a pause between applied voltage waveforms, thereby further improving luminous efficiency and increasing the amount of luminescence. Obtainable.

Further, when the external electrodes of the internal / external electrode type discharge lamp are grounded, radiation noise is reduced and insulation is facilitated.

Further, the inner and outer electrode type discharge lamp and the high frequency power supply may be integrated or may be configured as separate bodies separated from each other.

Further, the inner and outer electrode type discharge lamps can be dimmed and lit. In this case, the dimming means does not matter, but for example, a PWM type dimming means can be used.

According to a second aspect of the present invention, there is provided an inner / outer electrode type discharge lamp according to the first aspect, wherein the inner electrode has an electric field concentrating means formed of a projection.

As the protrusion, for example, a chip, a ring, or the like can be used. The tip body can be fixed by welding to the electrode shaft, and the ring body can be fixed by winding around the electrode shaft.

Thus, in the present invention, the electric field concentration means is constituted by the protrusions. When the electric field concentrating means of the internal electrode is formed by a projection, the electric field can be sufficiently protruded from the electrode shaft portion, so that a desired electric field concentration can be obtained.

Further, since the internal electrode approaches the external electrode via the protrusion, the starting voltage is reduced.

The inner and outer electrode type discharge lamp according to the third aspect of the present invention is the inner and outer electrode type discharge lamp according to the first aspect, wherein the inner electrode has an electric field concentrating means comprising a concave portion.

The concave portion of the internal electrode can be formed by partially pressing or casting the rod-shaped internal electrode.

Thus, in the present invention, the electric field concentrates at the edge of the concave portion.

Further, although the degree of concentration of the electric field is slightly smaller in the concave portion than in the projection, the manufacture of the internal electrode becomes easier.

According to a fourth aspect of the present invention, there is provided an inner / outer electrode type discharge lamp according to any one of the first to third aspects, wherein the internal electrodes are arranged such that the dispersion interval of the electric field concentrating means is greater than the distance between the electrodes. It is characterized by being small.

In the present invention, the distance between electrodes refers to the shortest distance between an internal electrode and an external electrode. Therefore, when the electric field concentrating means protrudes from the electrode axis of the internal electrode toward the external electrode, the shortest distance between the tip of the electric field concentrating means and the external electrode is the inter-electrode distance.

According to the present invention, the distance between the electric field concentrating means is defined based on the knowledge that the distance of the dispersion of the electric field concentrating means is related to the distance between the electrodes. If the dispersion interval of the electric field concentrating means is larger than the distance between the electrodes, discharge is likely to occur from portions other than the electric field concentrating means. When a discharge occurs from a portion other than the electric field concentrating means, the place where the discharge occurs moves with time as in the related art, causing flickering of the discharge.

Thus, in the present invention, the flicker of the discharge is more reliably fixed by setting the interval of dispersion of the electric field concentrating means as described above.

According to a fifth aspect of the present invention, there is provided an inner / outer electrode type discharge lamp according to any one of the first to fourth aspects, wherein the outer electrode has an electric field concentrating means having a longitudinal length of the translucent discharge vessel. Along the direction crossing the direction,
Further, it is characterized by comprising pores dispersed at the same pitch as the electric field concentration means of the internal electrode.

The present invention defines a preferable configuration of the electric field concentration means provided on the external electrode. By arranging the electric field concentration means at the same pitch on the external electrodes in addition to the internal electrodes,
The flicker of discharge is more reliably prevented.

Since the external electrode generally has a relatively large area, it is effective to form a hole in the external electrode in order to fix the position of the discharge current flowing into and out of the external electrode. It is a target. In addition, they are dispersed at the same pitch and opposed to each other so as to form a pair with the electric field concentration means of the internal electrodes.

The direction intersecting the longitudinal direction of the translucent discharge vessel is preferably perpendicular to the longitudinal direction, but means that it may be slightly inclined with respect to the longitudinal direction.

In the present invention, the term “pore” refers to a through-hole or a slit-like portion. "Slit" means an elongated opening.

Further, since the entire external electrodes must be substantially at the same potential, they need to be connected to each other by connecting portions. However, the connection portion may be formed on any portion of the external electrode.

For example, when forming a slit-shaped pore,
The connecting portion may be arranged at the center of the external electrode in the circumferential direction of the translucent discharge vessel, or may be arranged at one or both ends in the circumferential direction.

When the connecting portion is arranged at the center in the circumferential direction, the external electrode forms a pair of comb-shaped portions each of which extends on both sides around the connecting portion and has an open end.

When the connecting portion is disposed at one end, the external electrode extends to one side and forms a single comb blade with an open end.

Further, when connecting portions are disposed at both ends, the external electrode has a tapered shape in which both ends are closed by the connecting portions.

Thus, in the present invention, since the electric field concentrating means disposed on the external electrode is formed by the pore, the electric field concentrates on the edge of the pore, and the discharge current is concentrated on the external electrode during the cathode cycle. Since the gas flows from the edge of the means, the discharge is likely to be fixed. Further, even when the external electrode is in the anode cycle, the discharge current flows from the electric field concentrated portion, which is effective for fixing the discharge.

According to a sixth aspect of the present invention, there is provided an inner / outer electrode type discharge lamp according to any one of the first to fifth aspects, further comprising: a translucent discharge vessel having an aperture formed in a part thereof; And a transparent conductive film formed substantially between the light-emitting discharge vessel and the external electrode.

In the present invention, the aperture is an opening for light for causing generated light to be intensively led out of a part of the translucent discharge vessel, and is formed by combining one or more of the following structures, for example. Can be.

(1) The phosphor layer is formed by not forming the phosphor layer on the aperture portion.

2 A reflective film is formed on the inner surface side of the translucent discharge vessel except for the aperture.

(3) An external electrode is formed on the outer surface of the translucent discharge container except for the aperture portion.

The present invention specifies a configuration for reducing high frequency noise mainly radiated from the aperture portion when the light guide aperture is provided.

That is, when the discharge current of the internal and external electrode type discharge lamp is observed with an oscilloscope, the current waveform at the same frequency as the lighting frequency when the cathode cycle of the internal electrode or the application of the negative pulse is applied, but the anode cycle or the positive cycle. At the time of pulse application, a beard-like current of 10 times or more of the lighting frequency is observed. This beard-shaped current is due to the ozonizer discharge, and when a negative charge is accumulated in a minute portion of the surface of the light-transmitting discharge vessel serving as a barrier, that is, the discharge,
Discharge of the minute portion is stopped, and discharge current flows from another minute portion to perform discharge.

When the electric charge in the first minute portion disappears by diffusion, discharge occurs again in the minute portion.
Since this repetition is as quick as a few microseconds as compared with the lighting frequency, the discharge current is observed in a whisker-like manner. Electromagnetic noise is radiated from the minute discharge portion having such a high frequency. If the wavelength is λ, the electromagnetic noise is
It cannot pass through a gap of λ / 4 or less.

In general, since the external electrode generally satisfies the above conditions, it is difficult for electromagnetic noise to pass through the external electrode.

However, since no external electrode is provided at the aperture, electromagnetic noise is transmitted from the aperture and radiated to the outside, causing various obstacles.

Further, also in the external electrode, as described above, when the electric field concentrating means is provided, if a gap of λ / 4 or more is formed, there arises a problem that electromagnetic noise is transmitted.

On the other hand, in the present invention, since the light-transmitting conductive film is formed on substantially the entire outer surface of the light-transmitting discharge lamp, transmission of electromagnetic wave noise from the aperture can be prevented. .

Even if the external electrode is provided with an electric field concentrating means having a gap of λ / 4 or more, the transparent conductive film in the portion of the gap prevents transmission of electromagnetic noise.

Furthermore, since the conductive coating is transparent, it only slightly reduces the visible light transmittance, and the luminous efficiency of the inner and outer electrode type discharge lamps hardly changes.

Further, since the transparent conductive film can be formed easily and relatively inexpensively, the cost increase is small.

Further, since the transparent conductive film can be formed to be extremely thin, there is no problem in forming an external electrode thereon.

Further, the present invention has an excellent action and effect even for an inner / outer electrode type discharge lamp having an aperture without an electric field concentration means.

According to a seventh aspect of the present invention, there is provided an inner / outer electrode type discharge lamp according to any one of the first to fifth aspects, wherein a translucent discharge vessel partially formed with an aperture; A conductive mesh disposed substantially outside the light-transmitting discharge vessel outside the electrode.

The present invention specifies a configuration in which a conductive mesh body is used so that electromagnetic noise is not radiated to the outside.

In the present invention, the “mesh body” is a structure in which fine transmission holes are uniformly formed, and the transmission holes have a size of λ / 4 or less with respect to the wavelength λ of the electromagnetic wave to be blocked. Means what is configured. For example,
A mesh, a punched plate, or the like can be used as the mesh.

Further, since the mesh body is formed on the outer surface side of the external electrode, the arrangement of the external electrode deteriorates the workability due to the formation of the mesh body, and the adhesion of the external electrode to the outer surface of the translucent discharge vessel. Is not inhibited.

Further, since the mesh body is formed after the external electrodes are provided, the workability is good. In addition,
Even if the mesh body slightly floats from the external electrode or the aperture, its function is not affected.

Furthermore, the present invention is effective because it shields electromagnetic waves even from an internal / external electrode type discharge lamp having no electric field concentration means.

The lighting device according to the invention of claim 8 includes a lighting device main body; and the inner and outer electrode type discharge lamp according to any one of claims 1 to 7 provided in the lighting device main body. It is characterized by.

In the present invention, the term “illumination device” is a broad concept including any device that uses the light emitted from the inner and outer electrode-type discharge lamps for some purpose, such as an image reading device and various OA devices incorporating the same. A backlight device, a display device incorporating the same, a lighting device, and the like.

When the present invention is applied to a backlight device, it may be either a direct type backlight device or a sidelight type backlight device.

Further, the “illumination device main body” means a remaining portion of the illumination device excluding the inner and outer electrode type discharge lamps.

[0110]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross sectional view showing a first embodiment of the discharge lamp of the present invention.

FIG. 2 is a front view of the main part.

FIG. 3 is an expanded view showing the external electrodes.

FIG. 4 is a conceptual reduced longitudinal sectional view.

In each figure, 1 is a translucent discharge vessel, 2 is a phosphor layer, 3 is an internal electrode, and 4 is an external electrode.

The translucent discharge vessel 1 is formed of an elongated glass bulb having an outer diameter of 10 mm, a thickness of 1.0 mm, and a length of 300 mm, and has an aperture 1a. However, the aperture 1a is defined by not forming the phosphor layer 2 and the external electrode 3 described later.

The phosphor layer 2 is formed on the entire inner surface of the light-transmitting discharge vessel 1 except for the aperture 1a.
4: Tb phosphor is used. In FIG. 4, the illustration of the phosphor layer 2 and the electric field concentration means 3b is omitted.

Xenon is sealed in the translucent discharge vessel 1 as a rare gas at 40 kPa.

The internal electrode 3 includes an electrode shaft 3a and an electric field concentrating means 3b.

The electrode shaft 3 is made of a nickel rod having a diameter of 1 mm, and both ends are sealed to both ends of the translucent discharge vessel 1.
Furthermore, the end extends outside the translucent discharge vessel 1.

The electric field concentrating means 3b has a diameter of 1 mm and a length of 2 mm.
mm nickel bar pieces are welded to the electrode shaft 3a at intervals of 4 mm.

The external electrode 4 is made of aluminum foil.
Bonded to the outer surface of the translucent discharge vessel 1 with an adhesive 4a,
Except for the aperture 1a, it covers about 外 周 of the outer periphery.

The external electrode 4 is provided with an electric field concentrating means 4b.
Are formed. The electric field concentrating means 4b is configured by forming slits 4b1 of 0.5 mm at intervals of 4 mm along the longitudinal direction of the translucent discharge vessel 1 so as to extend in a direction perpendicular to the longitudinal direction. I have.

Further, a connecting portion 4c is formed in the outer electrode 4 at the center in the outer peripheral direction as shown in FIG. Have been.

The inner / outer electrode type discharge lamp of this embodiment is grounded with the outer electrode 3 and a high frequency voltage of a sine wave having a frequency of 50 kHz and an output voltage of 1.5 kV is applied between the pair of electrodes 3 and 4. The lamp current is 15
It was 0 mA.

The electric field is concentrated by the electric field concentrating means 3b and 4b formed on the internal electrode 3 and the external electrode 4, respectively. Therefore, the discharge flicker is 2% or less.

Further, the starting voltage was 500 V.

On the other hand, electric field concentration means 3b and 4
Except that b was not provided, an internal / external electrode type discharge lamp having the same specifications as this embodiment was manufactured and turned on. As a result, the starting voltage was 700V.

FIG. 5 is a conceptual reduced longitudinal sectional view showing a second embodiment of the inner and outer electrode type discharge lamp of the present invention.

In the figure, the same parts as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is different in that the internal electrode 3 is sealed only at one end of the translucent discharge vessel 1. The illustration of the phosphor layer 2 and the electric field concentration means 3b is omitted.

FIG. 6 is an enlarged front view of a main part showing internal electrodes in a third embodiment of the internal / external electrode type discharge lamp of the present invention.

The present embodiment is different in that the electric field concentration means 3b 'is constituted by a concave portion.

That is, the electric field concentrating means 3b 'is formed by pressing the internal electrodes 3' to form concave recesses facing each other at intervals of 4 mm.

FIG. 7 is a cross-sectional view showing a fourth embodiment of the inner and outer electrode type discharge lamp of the present invention.

FIG. 8 is a longitudinal sectional view of the essential part.

The present embodiment is different in that the electric field concentrating means 3b "of the internal electrode 3" is constituted by a ring.

That is, the electric field concentrating means 3b "is constituted by a ring body in which a molybdenum wire having a diameter of 0.6 mm is wound around the electrode shaft 3a" and fixed.

FIG. 9 is a cross-sectional view showing a fifth embodiment of the inner and outer electrode type discharge lamp of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is different in that a transparent conductive film 5 is formed on the outer peripheral surface of the translucent discharge vessel 1.

That is, a transparent conductive film 5 mainly composed of tin oxide is formed over almost the entire light-transmitting discharge vessel 1, and an external electrode 4 is provided thereon.

Since the transparent conductive film 5 covers the outer surface of the aperture 1a, the electromagnetic wave noise cannot pass through the aperture 1.

Even if the electric field concentrating means 4a formed on the external electrode 4 is formed by a slit of λ / 4 or more, since the transparent conductive film 5 is also formed on the inner surface of the slit, electromagnetic waves are not generated. There is no transmission through the external electrode 4.

FIG. 10 is a cross-sectional view showing a sixth embodiment of the inner and outer electrode type discharge lamp of the present invention.

FIG. 11 is an enlarged front view of a main part showing the conductive mesh body.

In the respective drawings, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is different from the first embodiment in that almost the entire light-transmitting discharge vessel 1 is covered with a conductive mesh 6 from above the external electrode 4.

That is, the external electrode 4 is connected to the translucent discharge vessel 1.
After that, the conductive mesh body 6 is provided on the external electrode 4 over substantially the entirety of the translucent discharge vessel 1.

The conductive mesh body 6 is knitted.

Then, after inserting the translucent discharge vessel 1 having the external electrodes 4 disposed in the cylindrical conductive mesh body 6 having a large diameter with respect to the translucent discharge vessel 1, When both ends of the conductive mesh body 6 are pulled, the diameter of the conductive mesh body 6 is reduced, and the conductive mesh body 6 comes into close contact with the surface of the external electrode 4 and the aperture 1a.

FIG. 12 is a cross-sectional view showing a sidelight type backlight device as a first embodiment of the illumination device of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 11 denotes an inner / outer electrode type discharge lamp, 12 denotes a lamp holder, and 13 denotes a light guide plate.

The inner and outer electrode type discharge lamp 11 has the same structure as that shown in FIG.

The lamp holder 12 surrounds the inner and outer electrode type discharge lamps 11 and also holds the edge of the light guide plate 13.

The light guide plate 13 is made of a transparent acrylic resin, and emits light from the inner and outer electrode type discharge lamps 11 from the side, and uniformly emits light from the front while repeating total internal reflection.

Accordingly, a display (not shown) such as a liquid crystal is illuminated from the back on the front of the light guide plate 13.

FIG. 13 is a conceptual diagram showing an image reading device as a second embodiment of the illumination device of the present invention.

In the figure, reference numeral 21 denotes an inner and outer electrode type discharge lamp, 22 denotes a light receiving means, 23 denotes a signal processing means, 24 denotes a document placing surface, 25 denotes a reflection plate, and 26 denotes a case.

The inner and outer electrode type discharge lamp 21 is the same as the embodiment shown in FIG. And the aperture 1a
Is emitted toward a document (not shown) via the document placing surface 24.

The light receiving means 22 is arranged to receive the reflected light from the document surface.

The signal processing means 23 processes the output signal of the light receiving means 22 to form an image signal.

The original placing surface 24 is made of transparent glass.
The original is placed on top of it.

The reflection plate 25 is formed of the inner and outer electrode type discharge lamp 21.
Is reflected toward the document.

The case 26 houses each of the above components.

Thus, the inner and outer electrode type discharge lamps 21 and the light receiving means 22 and the original placing surface 24 are relatively scanned. That is, as one or both of them move in the opposite direction, the light receiving means 22 sequentially receives the reflected light from the document surface in a direction perpendicular to the moving direction.

The image reading apparatus according to the present embodiment is applicable to OA equipment such as a copying machine, an image scanner, and a facsimile.

[0168]

According to the first to seventh aspects of the present invention, a discharge medium containing a rare gas as a main component is sealed in the light-transmitting discharge vessel, and is disposed on the outer surface of the light-transmitting discharge vessel. By providing a pair of electrodes consisting of external electrodes and internal electrodes extending in the longitudinal direction and sealed in the translucent discharge vessel, by dispersing the electric field concentrating means in at least the internal electrodes along the longitudinal direction, It is possible to provide an internal / external electrode type discharge lamp in which the outflow point or the inflow point of the discharge current is fixed and the flicker of the discharge is reduced.

According to the second aspect of the present invention, there is provided an internal / external electrode type discharge lamp in which a desired electric field concentration is obtained and the starting voltage is reduced by providing the electric field concentrating means of the internal electrode with a projection. be able to.

According to the third aspect of the present invention, in addition, since the electric field concentrating means of the internal electrode comprises a concave portion, it is possible to provide an internal / external electrode type discharge lamp in which the internal electrode can be easily manufactured.

According to the fourth aspect of the present invention, in addition, since the dispersion interval of the electric field concentrating means of the internal electrode is smaller than the distance between the electrodes, the inflow / outflow point of the discharge current from the electric field concentrating means can be ensured. Shaped discharge lamps can be provided.

According to the fifth aspect of the present invention, the electric field concentrating means of the external electrode is dispersed along the direction crossing the longitudinal direction of the translucent discharge vessel and at the same pitch as the electric field concentrating means of the internal electrode. The inner and outer electrode-type discharge lamps can more reliably fix the discharge by having the gaps formed.

According to the sixth aspect of the present invention, a transparent conductive film is formed on substantially the entire light-transmitting discharge vessel between the light-transmitting discharge vessel in which the aperture is formed and the external electrode. It is possible to provide an internal / external electrode type discharge lamp that reduces electromagnetic wave noise radiated from the aperture and reduces radiation of electromagnetic wave noise from the external electrode even when the electric field concentrating means including holes is provided in the external electrode. .

According to the seventh aspect of the present invention, in addition, since the conductive mesh body is disposed on substantially the entirety of the light-transmitting discharge vessel from outside the external electrode, the workability of forming the conductive mesh body is improved. It is possible to provide an inner / outer electrode type discharge lamp which is good and has an external electrode in close contact with the outer surface of the translucent discharge vessel.

According to the invention of claim 8, it is possible to provide a lighting device having the effects of claims 1 to 7.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of an internal / external electrode type discharge lamp of the present invention.

FIG. 2 is a front view of the same main part.

FIG. 3 is a development view showing the same external electrodes.

FIG. 4 is a conceptual reduced longitudinal sectional view of the same.

FIG. 5 is a conceptual reduced longitudinal sectional view showing a second embodiment of the inner and outer electrode type discharge lamp of the present invention.

FIG. 6 is an enlarged front view of a main part showing an internal electrode in a third embodiment of the internal / external electrode type discharge lamp of the present invention.

FIG. 7 is a cross-sectional view showing a fourth embodiment of the inner and outer electrode type discharge lamp of the present invention.

FIG. 8 is a longitudinal sectional view of a main part of the same.

FIG. 9 is a cross-sectional view showing a fifth embodiment of the internal / external electrode discharge lamp of the present invention.

FIG. 10 is a cross-sectional view showing a sixth embodiment of the internal / external electrode discharge lamp of the present invention.

FIG. 11 is an enlarged front view of a main part showing the conductive mesh body.

FIG. 12 is a cross-sectional view showing a sidelight-type backlight device as a first embodiment of the lighting device of the present invention.

FIG. 13 is a conceptual diagram showing an image reading device as a second embodiment of the illumination device of the present invention.

FIG. 14 is a cross-sectional view showing a conventional internal / external electrode type discharge lamp.

FIG. 15 is a partially enlarged light output waveform diagram for explaining flickering of discharge in a conventional internal / external electrode type discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Translucent discharge container 1a ... Aperture 2 ... Phosphor layer 3 ... Internal electrode 3a ... Electrode shaft part 3b ... Electric field concentration means 4 ... External electrode 4a ... Adhesive 4b ... Electric field concentration means 4b1 ... Slit 4c ... Connection part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kunio Yuasa 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Litec Corporation (72) Inventor Teiji Shimokawa 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo No. Toshiba Litec Co., Ltd.

Claims (8)

[Claims] A discharge medium mainly composed of a rare gas sealed in the light-transmitting discharge vessel; one of which is transparent so as to generate a discharge inside the light-transmitting discharge vessel; An external electrode disposed on the outer surface of the light-emitting discharge vessel, and the other is constituted by an internal electrode extending in the light-transmitting discharge vessel in the longitudinal direction and sealed therein. And a pair of electrodes provided with electric field concentrating means dispersed along the lines. 2. An internal / external electrode type discharge lamp according to claim 1, wherein the electric field concentrating means of the internal electrode comprises a projection. 3. The internal / external electrode type discharge lamp according to claim 1, wherein said internal electrode has a concave portion whose electric field concentration means. 4. An internal / external electrode type discharge lamp according to claim 1, wherein the distance between the dispersion of the electric field concentrating means is smaller than the distance between the electrodes. 5. The external electrode is formed of pores in which the electric field concentrating means extends along a direction crossing the longitudinal direction of the translucent discharge vessel and is dispersed at the same pitch as the electric field concentrating means of the internal electrode. 5. An internal and external electrode type discharge lamp according to claim 1, wherein: 6. A light-transmissive discharge vessel partially formed with an aperture; and a transparent conductive coating formed substantially entirely on the light-transmissive discharge vessel between the light-transmissive discharge vessel and an external electrode; 6. The method according to claim 1, further comprising:
The internal / external electrode type discharge lamp according to any one of the above. 7. A light-transmitting discharge vessel partially having an aperture formed therein; and a conductive mesh body disposed substantially outside the light-transmitting discharge vessel outside the external electrode. 6. An inner and outer electrode type discharge lamp according to claim 1, wherein 8. A lighting device comprising: a lighting device main body; and an inner / outer electrode type discharge lamp according to any one of claims 1 to 7 disposed in the lighting device main body.