JP2000223079A - Fluorescent lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp and a lighting system capable of obtaining a stable light output from a light projecting part while suppressing flickering. SOLUTION: This fluorescent lamp is equipped with a cylindrical bulb 1 in which discharge gas such as xenon is filled and a fluorescent layer 2 is formed on its inner surface, a light projecting part 5 formed longitudinally along the bulb on the fluorescent layer 2, and a pair of strip electrodes 4, 4 formed longitudinally along the outer surface of the bulb 1 within an angle range of not more than 180 deg. to the center of the bulb so as to sandwich the light projecting part 5. Since the pair of strip electrodes 4, 4 are formed within the angle range of not more than 180 deg. to the center of the bulb 1 so as to sandwich the light projecting part 5, a discharge shrinking phenomenon is not visible because it is hidden in the back side of the strip electrodes. Therefore, flickering of visible light projected through the light projecting part 5 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluorescent lamp and an illuminating device having electrodes formed on the outer surface of a bulb.

[0002]

2. Description of the Related Art A fluorescent lamp in which a discharge gas mainly composed of xenon is sealed in a cylindrical glass bulb as a light source of a reading apparatus such as a copying machine and an electrode is provided on the outer surface of the bulb is being used. As such an external electrode type fluorescent lamp, for example, a fluorescent lamp described in Japanese Patent Application Laid-Open No. Hei 5-98851 is known. This prior art fluorescent lamp has a pair of strip electrodes formed along the longitudinal direction of the bulb.

Further, it has been proposed to use a fluorescent lamp having a similar structure as a display element, for example, in Japanese Patent Laid-Open No. 5-8210.
No. 1 discloses this.

On the other hand, a linear internal electrode extending along the central axis of the bulb is sealed in a cylindrical bulb filled with a discharge gas mainly composed of xenon, and a strip electrode is formed on the outer surface of the bulb along the internal electrode. A fluorescent lamp is described in JP-T-8-508363.

In these prior arts, a fluorescent layer is formed on the inner surface of the bulb, a discharge gas mainly composed of xenon is sealed in the bulb, and electrodes are formed on the outer surface of the bulb. When a voltage is applied between the outer surface electrodes or between the inner electrode and the outer electrode, a so-called silent discharge or dielectric barrier discharge using a glass wall as a dielectric is generated, and the xenon gas is discharged, so that the xenon molecules are discharged. Emits ultraviolet light having a wavelength of 172 nm. When the ultraviolet light excites the phosphor, the fluorescent lamp emits visible light.

[0006]

In the fluorescent lamp of the prior art described above, visible light is emitted in one direction by a light emitting portion such as an aperture formed by slitting an area where no phosphor layer is formed. Used as

In the above-mentioned conventional fluorescent lamp, the lamp efficiency can be increased by increasing the gas pressure of xenon gas.

[0008] However, when the gas pressure of the xenon gas is increased, a phenomenon occurs in which the discharge contracts, and this contraction causes countless discharges to occur. Due to this phenomenon, the light output from the light projection unit of the fluorescent lamp becomes unstable, and is perceived as flickering by humans.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a fluorescent lamp and a lighting device which can obtain a stable light output from a light emitting portion and suppress flicker.

[0010]

A fluorescent lamp according to claim 1 includes a cylindrical bulb in which a discharge gas is filled and a phosphor layer is formed on an inner surface; A pair of band-shaped electrodes formed along the longitudinal direction on the outer surface of the bulb within an angle range of 180 ° or less with respect to the center of the bulb so as to sandwich the light projection section; ; Characterized by having;

In the claims and the following claims, definitions and technical meanings of terms are as follows unless otherwise specified.

[0012] The valve has a tubular shape and is formed in a shape such as a straight tube, a bent shape or an annular shape. The bulb may be made of a soft glass such as soda lime glass or lead glass, but may be made of a hard glass such as borosilicate glass, semi-hard glass, or quartz glass, if necessary. Good. In short, any material that satisfies the translucency and airtightness, the heat resistance at the operating temperature of the fluorescent lamp, and the workability is acceptable.

The discharge gas is selected to have a composition that causes a discharge in the bulb, but a gas mainly composed of a rare gas containing xenon is preferable. In addition to xenon, krypton, neon, argon and the like may be mixed and used as the rare gas. When krypton is used in a mixture with xenon, flicker in brightness can be suppressed.

Xenon excites the phosphor with ultraviolet light having a wavelength of 172 nm generated by low-pressure discharge to emit visible light. The sealing pressure of the rare gas mainly composed of xenon is not particularly limited, but is preferably 133 Pa to 26.6 kPa.

Further, a metal vapor such as mercury vapor can be used as the discharge gas. In this case, it is necessary to take into consideration the deterioration of the phosphor layer due to the metal vapor discharge and the fluctuation of the metal vapor pressure due to the change of the ambient temperature. There is.

The phosphor layer is one that emits visible light when excited by ultraviolet rays emitted by the discharge of the discharge gas, and is formed directly or indirectly on the inner surface of the bulb. Indirect means, for example, forming a reflective film mainly composed of metal oxide particles having high visible light reflectance and a transparent protective layer of a metal oxide layer mainly composed of alumina fine particles or the like on the inner surface of the bulb. This includes forming a phosphor layer on the inner surface side.

The phosphor used in the phosphor layer is 3
A wavelength-emitting phosphor, a calcium halophosphate phosphor, or the like can be used. When the discharge gas is xenon and a fluorescent lamp is used as a light source for reading, LaPO ₄ :
A green light-emitting phosphor such as Ce or Tb may be used.

Further, a non-fluorescent substance such as a binder and an electron-emitting particle can be mixed in the fluorescent layer in addition to the fluorescent substance.

The light projecting portion means a region formed along the longitudinal direction of the bulb so that the visible light emitted from the phosphor layer is projected to the outside of the bulb. In general, if the light projecting portion is a so-called aperture in which the phosphor layer is not formed, the visible light can be efficiently projected to the outside of the bulb, but is not limited thereto. For example, a reflective layer may be formed on the inner surface or outer surface of the bulb except for the light projection unit, and the phosphor layer may be formed on the entire circumference of the bulb. Further, the phosphor layer is formed on the entire circumference of the bulb. In the case where visible light is projected in one direction due to the usage form of the fluorescent lamp, a portion facing the one direction may be defined as a light projection unit.

The strip electrode is formed of a conductive material on the outer surface of the bulb along the longitudinal direction. The strip-shaped electrode may be formed by attaching a thin plate or mesh of a conductive metal such as aluminum to the outer surface of the valve with an adhesive, or by applying a conductive paste, drying and firing. When a conductive metal mesh is used for the strip electrode, it is necessary to suppress the visible light transmittance to such an extent that the visible light does not flicker near the electrode through the mesh.

In forming a pair of strip electrodes, one side of the strip electrodes sandwiches the light projecting portion and is formed within an angle range of 180 ° or less with respect to the center of the bulb. When the light projecting portion is formed by an aperture or an opening in the reflective layer, it is desirable, but not essential, to align one side of the strip electrode with the side edge of the light projecting portion.

The strip electrode may have a transparent insulating coating formed on the outside thereof. This transparent insulating coating is preferably formed on the entire outer surface of the bulb. In the case of a pair of strip electrodes, if the transparent insulating coating is formed on the entire outer surface of the bulb, the insulation between the two electrodes can be improved. This transparent insulating coating can be applied by a method of dip coating and solidifying a transparent silicone resin, or a method of applying a heat-shrinkable tube such as a transparent fluororesin having excellent heat resistance.

When a high-frequency voltage is applied between a pair of strip electrodes, a so-called silent discharge is generated via the bulb.
When the filling pressure of the discharge gas filled inside becomes higher than a certain value (15 kPa or more in the case of xenon gas), the discharge contracts and a whisker-like discharge occurs. In particular,
In the vicinity of the phosphor near the electrode, the discharge shrinkage phenomenon appears as uneven brightness, so that the light output seems to flicker.

However, in the fluorescent lamp according to the first aspect of the present invention, the pair of strip electrodes are formed within an angle range of 180 ° or less with respect to the center of the bulb so as to sandwich the light projecting portion. Since the phenomenon is hidden behind the strip-shaped electrode and cannot be seen, it is possible to suppress the visible light projected through the light projection unit from flickering.

A fluorescent lamp according to a second aspect of the present invention has a cylindrical bulb in which a discharge gas is sealed and a phosphor layer is formed on the inner surface; an internal electrode sealed in the bulb; A light projecting portion formed along the light projecting portion; and a strip electrode formed along the longitudinal direction on the outer surface of the bulb within an angle range of 180 ° or less with respect to the center of the bulb including the light projecting portion. It is characterized by doing.

When the internal electrode is used as in the fluorescent lamp according to the second aspect, the band electrode and the light projecting portion, which is the other electrode for generating a discharge, are positioned at a distance of 18 cm from the center of the bulb.
It is necessary to dispose it within an angle range of 0 ° or less.

The internal electrode is sealed at one end or both ends of the bulb. When the internal electrodes are sealed at both ends, in addition to individually independent electrodes, the internal electrodes extend along both ends along the central axis of the bulb. May be done. In addition, a valve sealed from one end of the valve along the central axis of the valve is also included.

Further, the strip-shaped electrode is positioned at 1
A plurality may be formed within an angle range of 80 ° or less.

[0029] In the fluorescent lamp of the second aspect, similarly to the first aspect, the visible light projected through the light projection unit is suppressed from being seen flickering.

A third aspect of the present invention is the fluorescent lamp according to the first or second aspect, wherein a discharge gas mainly composed of xenon having a partial pressure of 15 kPa or more is sealed in the bulb.

When the discharge gas is xenon, it is possible to light with stable brightness without affecting the ambient temperature, so that the start-up start-up characteristic can be improved and the xenon gas filling pressure is 15 kPa or more. As a result, the lighting efficiency can be improved while suppressing the effect of flicker.

The lighting device of claim 4 is the lighting device of claims 1 to 3.
A lighting device, comprising: the fluorescent lamp according to any one of the preceding claims; and a device main body to which the fluorescent lamp is mounted.

The illumination device may be a device for general illumination in addition to a device used for a reading device or a display device used in a copying machine, a facsimile, or the like. When a fluorescent lamp is used as a display element, it can be used as a display device.

The apparatus main body may be provided with a fluorescent lamp lighting device, but is not essential. As the fluorescent lamp lighting device, a device that outputs a high-frequency voltage is used, and the output waveform may be a pulse shape instead of a sine wave.

According to the illumination device of the fourth aspect, it is possible to provide an illumination device having the functions of the first to third aspects.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a rare gas fluorescent lamp according to a first embodiment of the present invention. FIG. 1 is a plan view and FIG.
Is an enlarged sectional view.

Reference numeral 1 denotes a cylindrical valve having an outer diameter of 12 m.
m, formed of borosilicate glass having a tube length of 300 mm.

On the inner surface of the valve 1, LaPO ₄ : Ce,
A phosphor layer 2 is formed by applying a Tb phosphor as a main component, and a xenon gas of 40 kPa is sealed therein and sealed by a pinch seal portion 1a.

On the outer surface of the bulb 1, a pair of strip electrodes 4, 4 are formed with an adhesive layer 3 interposed therebetween. The strip electrodes 4 and 4 are made of aluminum tape, and are connected to a lighting device (not shown) by a power supply terminal (not shown) provided at one end of the bulb 1.

Reference numeral 5 denotes an aperture as a light projecting portion, which is formed by applying the phosphor layer 2 so as to form a slit along the longitudinal direction of the bulb 1. The opening angle θ of the aperture 5 with respect to the center of the valve 1 is about 60
°.

The pair of electrodes 4 and 4 are formed within an angle range of 180 ° or less with respect to the center of the bulb 1 so as to sandwich the aperture 5. The pair of electrodes 4 and 4 are adhered so that one side edge facing each other coincides with the opening side edge of the aperture, and the arrangement angle φ formed by the other side edge with respect to the center of the bulb is about 170. °.

A frequency of 30 k is applied between the pair of strip electrodes 4 and 4.
A high frequency voltage of 2.5 kV with a frequency of 2.5 Hz is applied. This voltage causes a so-called silent discharge between the strip electrodes.

According to the present embodiment, since the arrangement angle of the pair of strip electrodes 4 and 4 stuck so as to sandwich the aperture 5 is 180 ° or less, the back side of the strip electrodes 4 and 4 by the silent discharge. Even if countless whisker-like discharges are generated due to the discharge contraction, the discharge portions on the back surfaces of the band-shaped electrodes 4 and 4 are not directly seen from the aperture 5 side, so that the flickering of the light output is suppressed.

Next, a second embodiment will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 3 is an enlarged sectional view of a rare gas fluorescent lamp according to a second embodiment of the present invention.

Reference numeral 6 denotes an internal electrode, which has a diameter of 1.2 mm.
It consists of i-line. The internal electrode 6 is inserted and sealed from the pinch seal portion 1a along the central axis of the bulb 1.

A pair of strip electrodes 4 and 4 are attached so as to sandwich the aperture 5, and both strip electrodes 4 and 4 are connected to the ground potential. The internal electrode 6 has a frequency of 30.
A high frequency voltage of kHz and a voltage of 2.5 kV is applied, and this voltage causes a so-called silent discharge between the internal electrode 6 and the strip electrodes 4 and 4.

In the present embodiment, the band electrodes 4 and 4 need not be in a pair, but may be one or three or more if the arrangement angle φ is 180 ° or less including the aperture. .

According to the present embodiment, the pair of strip electrodes 4
4 is 180 ° or less including the aperture 5, even if countless whisker-like discharges occur due to discharge contraction on the back side of the zonal electrodes 4 and 4 due to the silent discharge, the zonal shape as viewed from the aperture 5 side. Since the discharge portions on the back surfaces of the electrodes 4 and 4 are not directly visible, flickering of the light output is suppressed.

In the first and second embodiments, the phosphor layer 2 is not provided with the aperture 5 and the TiO ₂
A light projection unit may be provided so that the light reflection film mainly composed of fine particles has an opening angle θ of about 60 ° with respect to the center of the bulb. The phosphor layer is formed by coating the phosphor layer on the inside of the light reflection film. When the phosphor layer is also applied to the light projecting portion, the light output is further integrated to further stabilize the light output. realizable. In the modification with the light reflecting film, even if the arrangement angle of the strip electrode exceeds 180 ° including the light projecting portion, the light output is diffused if the phosphor layer is formed in the light projecting portion. However, a certain degree of flicker can be reduced, but fluctuations in brightness cannot be eliminated.

FIG. 4 is a conceptual sectional view showing an image reading apparatus according to the third embodiment.

Reference numeral 11 denotes the fluorescent lamp of the above embodiment, 12 denotes light receiving means, 13 denotes signal processing means, 14 denotes a document placing surface, 1
5 is a reflection plate, 16 is a case.

The light emitted from the light projecting portion of the fluorescent lamp 11 is applied to an original (not shown) via the original placing surface 14.

The light receiving means 12 is arranged to receive the light reflected from the document surface. The signal processing means 13 processes the output signal of the light receiving means 12 to form an image signal.
The original placing surface 14 is made of transparent glass, and the original is placed thereon. The reflecting plate 15 directs the light emitted from the fluorescent lamp 11 to the document placing surface 14. The case 15 houses each of the above components.

The fluorescent lamp 11 and the light receiving means 12 and the original placing surface 14 relatively scan each other. That is, as one or both of them move in the opposite direction, the light receiving means 12 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.

[0057]

According to the fluorescent lamp of the first aspect, the pair of strip electrodes are formed within an angle range of 180 ° or less with respect to the center of the bulb so as to sandwich the light projecting portion. Since the discharge shrinkage phenomenon is hidden behind the strip electrode and cannot be seen, the visible light projected through the light projection unit is suppressed from being seen flickering.

According to the fluorescent lamp of the second aspect, the strip electrode is formed within an angle range of 180 ° or less with respect to the center of the bulb including the light projecting portion. The visible light projected through the part is prevented from flickering.

According to a third aspect of the present invention, since the discharge gas mainly composed of xenon is filled in the bulb at a partial pressure of 15 kPa or more, the starting rise characteristic can be improved, and the lighting efficiency is improved while suppressing the influence of flicker. be able to.

According to the illumination device of the fourth aspect, it is possible to provide an illumination device having the effects of the first to third aspects.

[Brief description of the drawings]

FIG. 1 is a plan view of a rare gas fluorescent lamp according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of FIG.

FIG. 3 is an enlarged sectional view of a rare gas fluorescent lamp according to a second embodiment of the present invention;

FIG. 4 is a conceptual cross-sectional view illustrating an image reading apparatus according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... bulb, 2 ... phosphor layer, 4 ... strip electrode, 5 ... aperture as light projection part, 6 ... internal electrode.

Claims (4)

[Claims] 1. A cylindrical bulb filled with a discharge gas and having a phosphor layer formed on an inner surface thereof; a light projecting portion formed on the phosphor layer along a longitudinal direction of the bulb; 180 ° with respect to the center of the bulb so as to sandwich the projection unit
A pair of band-shaped electrodes formed along the longitudinal direction on the outer surface of the bulb within an angle range of not more than °. 2. A cylindrical bulb in which a discharge gas is sealed and a phosphor layer is formed on an inner surface; an internal electrode sealed in the bulb; and light formed along a longitudinal direction of the bulb. A projection section; and a strip-shaped electrode formed along the longitudinal direction on the outer surface of the bulb within an angle range of 180 ° or less with respect to the center of the bulb including the light projection section. And fluorescent lamp. 3. The fluorescent lamp according to claim 1, wherein a discharge gas mainly composed of xenon having a partial pressure of 15 kPa or more is sealed in the bulb. 4. A lighting device comprising: the fluorescent lamp according to claim 1; and a device main body to which the fluorescent lamp is mounted.