JPH09325707A - Irradiation unit using external electrode type fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the external electrode type fluorescent lamp irradiation unit which can increase illuminance on document read surfaces of various information equipment or the quantity of light of the back light device of a liquid crystal display panel. SOLUTION: External electrodes of an external electrode type fluorescent lamp 20 transmit light and when the lamp 20 is turned on, the light is emitted to the outside through an aperture 4 and also emitted from a light transmission part 6 provided to the external electrodes 2 and 2'. The light emitted by the light transmission part 6 is reflected by a reflecting material 11 and emitted from the opening part of a U-shaped reflecting material. The external electrodes of the lamp 20 are made partially light-transmissive and the light transmitted through the light transmission part 6 is reflected by the reflecting material 11 to irradiate an irradiated area, so the quantity of light can be made larger than that of a conventional irradiation unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an irradiation unit using an external electrode type fluorescent lamp which is used for illuminating originals of information equipment such as facsimiles, copying machines and image readers, and for backlight devices of liquid crystal display panels. Regarding

[0002]

2. Description of the Related Art As a fluorescent lamp used for a light source of OA equipment, a backlight of a display device, and the like, a pair of external electrodes in a band shape are arranged on the outer surface of a glass tube, and a high frequency voltage is applied to these electrodes. There is known an external electrode type fluorescent lamp which is turned on. FIG. 9 is a view showing an example of the above-mentioned external electrode type fluorescent lamp, which shows a sectional view perpendicular to the tube axis of the external electrode type fluorescent lamp. As shown in the figure, the external electrode type fluorescent lamp 10 has a pair of external electrodes 2 and 2 ′ in the form of strips arranged on the outer surface of the glass tube 1, and a rare gas or the like is sealed inside the glass tube 1 and the glass tube 1 A fluorescent substance 3 is applied to the inner surface of the tube 1, and a continuous high frequency voltage or a pulsed high frequency voltage is applied to the external electrodes 2 and 2'to turn on the light.

The external electrode type fluorescent lamp 10 generates a discharge in a discharge space inside the glass tube 1 sandwiched between the external electrodes 2 and 2'by a high frequency voltage applied to the pair of external electrodes 2 and 2 '. The fluorescent material 3 applied to the inner surface of the glass tube 1 is caused to emit light by the ultraviolet rays generated by this discharge. The light generated by the discharge is radiated to the outside from the aperture 4 and its opposite surface, and is radiated from the aperture 4. The irradiated light is applied to the irradiation target.

[0004]

By the way, in recent years, in information devices such as facsimiles, copying machines, and image readers, it has been required to increase the document reading speed.
There is a demand for increasing the light output of the external electrode type fluorescent lamp. Further, in a backlight device of a liquid crystal display panel, a backlight device that can obtain a high light output with a small input power is desired. The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an illuminance on a document surface or a backlight of a liquid crystal display panel in various information devices such as a facsimile, a copying machine, and an image reader. It is an object of the present invention to provide an irradiation unit using an external electrode type fluorescent lamp capable of increasing the amount of light of an apparatus or the like.

[0005]

[Means for Solving the Problems] When the light output emitted from the external electrode type fluorescent lamp when holes or slits were provided in the external electrodes was examined, the size and position of the holes and slits were properly determined. If selected, it became clear that the amount of light emitted from the aperture does not decrease even if the electrode area is reduced by the amount of the holes and slits provided (this point has been proposed by the present applicant). See Japanese Patent Application No. 8-109109). That is, by providing the holes, slits and the like (hereinafter referred to as light transmitting portions), the amount of light emitted from the external electrode type fluorescent lamp is increased by the amount of light emitted through the light transmitting portions. Therefore, the amount of light of the external electrode type fluorescent lamp can be increased by utilizing the light emitted through the light transmitting portion. Therefore, if a reflecting member is provided on the outside of the external electrode type fluorescent lamp and the light emitted from the light transmitting portion is reflected by the reflecting member to irradiate the object to be irradiated, the same lamp input power can be used. It is possible to increase the possible light output.

On the basis of the above points, the present invention seals a predetermined amount of a rare gas inside a glass tube coated with a fluorescent substance, arranges at least a pair of electrodes in the tube axial direction on the outer surface of the glass tube, and externally In an irradiation unit including an external electrode type fluorescent lamp provided with an aperture that emits light, at least a part of the electrodes is translucent, and a reflector is arranged apart from the external electrode type fluorescent lamp. At least a part of the transmitted light from the electrode is reflected by the reflective material to the irradiation area of the radiated light from the aperture.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the structure of an irradiation unit according to a first embodiment of the present invention, which shows the structure of an irradiation unit used in a backlight device of a liquid crystal display panel. ing. This figure shows a cross section perpendicular to the tube axis of the external electrode type fluorescent lamp of the irradiation unit of the present embodiment, 20 is an external electrode type fluorescent lamp having a translucent portion in the external electrode, and 11 is a U-shaped. As the reflecting material, aluminum whose U-shaped inner surface was mirror-finished was used as the reflecting material.

FIG. 2 shows a cross section perpendicular to the tube axis of an external electrode type fluorescent lamp (hereinafter abbreviated as a lamp) having a translucent portion in the external electrode. A hole or a slit is formed on the outer surface of the glass tube 1. A pair of strip-shaped external electrodes 2, 2 ′ having a light-transmitting part 6 are provided, a rare gas or the like is sealed inside the glass tube 1, and the fluorescent material 3 is applied to the inner surface of the glass tube 1. Similarly to the lamp shown in FIG. 9, a continuous high-frequency voltage or a pulsed high-frequency voltage is applied to the external electrodes 2 and 2'to turn them on.

3A to 3C are views showing an example of the shape of an external electrode having a transparent portion used in the present invention. The external electrode having a transparent portion is, for example, as shown in FIG. It is possible to use those having slits in the external electrode, those having a plurality of holes in the external electrode as shown in B, or those using the external electrode formed of a mesh as shown in C.

In the irradiation unit having the configuration shown in FIG. 1, when the lamp 20 is turned on, light is emitted from the aperture 4 to the outside, and at the same time, light is emitted from the light transmitting portion 6 provided on the external electrodes 2 and 2 '. The light emitted from the translucent part 6 is a reflection material 1
1 and is radiated from the opening of the U-shaped reflector.
That is, in the irradiation unit of the present embodiment, the light emitted from the translucent portion 6 is reflected by the reflecting material 11 and emitted from the opening of the U-shaped reflecting material for use. Compared with the case of using a lamp without the translucent part 6,
The light output can be increased.

In order to confirm the effect of this embodiment, a comparative experiment was performed using the irradiation unit shown in FIG. 1 for a lamp having no light transmitting portion and a lamp having a light transmitting portion. In the above experiment, the irradiation unit of FIG.
A lamp having a light-transmitting portion having a tube diameter of 8 mm and a lamp having no light-transmitting portion were installed at a position 30 mm from the opening of the U-shaped reflector 11 (distance a = 30 mm in FIG. 1), and the U-shaped reflector was used. The light receiver 12 provided in the opening of 11 was moved in the direction of the arrow in the figure to measure the light quantity distribution. In addition, as a lighting condition, a voltage was applied to the lamp in a pulse shape of 1600 V and 75 kHz. The input voltage of the inverter used to generate the pulsed voltage is 24V and the input current is 0.
It was 6A.

FIG. 4 is a diagram showing the above measurement results. The thick line in FIG. 4 is the illuminance distribution when a lamp having a light transmitting portion is used, and the thin line is the illuminance distribution when a lamp having no light transmitting portion is used. The horizontal axis represents the position of the light receiver 12 shown in FIG. 1 (the center of the optical axis is 0 mm), and the vertical axis represents the light receiver 12.
Is the amount of light received by. As is apparent from the figure, when the lamp 20 having the light transmitting portion is used, the amount of light emitted from the irradiation unit is the lamp 1 having no light transmitting portion.
The effect of this example was confirmed to be larger than that when 0 was used.

FIG. 5 is a diagram showing the structure of an irradiation unit according to the second embodiment of the present invention, which shows the structure of the irradiation unit used for illuminating the original of an information device. The figure shows a cross section perpendicular to the lamp tube axis of the irradiation unit, in which 20 is a lamp having a translucent portion in the external electrode, and 21.
Is a main reflecting mirror, 22 is a sub-reflecting mirror, and 23 is a document glass on which a document to be read is placed. The main reflecting mirror 21 is arranged so as to cover the lamp 20, and the part a in the figure is formed in a substantially elliptical or circular curved shape so as to collect light, and the end b of the main reflecting mirror 21 is formed. Is bent so that the light emitted from the lamp 20 does not directly enter the image receiving element (not shown). The sub-reflector 2
2 is formed in a substantially elliptical or circular curved shape, and the lamp 2
The light emitted from 0 is collected.

In the irradiation unit having the structure shown in FIG. 5, the light emitted from the aperture 4 and the light transmitting portion 6 of the lamp 20 is directly irradiated on the original glass 23 and reflected by the main reflecting mirror 21 and the sub-reflecting mirror 22. Then, the original glass 23 is illuminated. The light is reflected on the surface of the original placed on the original glass, passes through a slit S provided between the main reflecting mirror 21 and the sub-reflecting mirror 22, and passes through an optical system including a mirror, a lens, etc. And enters an image receiving element (not shown).

In the irradiation unit of this embodiment, the light emitted from the aperture 4 and the translucent portion 6 of the lamp 20 is reflected by the main reflecting mirror 21 and the sub-reflecting mirror 22 to irradiate the original surface on the original glass 23. Therefore, as in the first embodiment, as compared with the case of using the lamp without the light transmitting portion 6,
The light output can be increased. In order to confirm the effect of the present embodiment, a comparative experiment was performed using the irradiation unit shown in FIG. 5 for a lamp having no light transmitting portion and a lamp having a light transmitting portion. In the above experiment, in the irradiation unit shown in FIG. 5, a lamp having a light transmitting portion having a length of 370 mm and a tube diameter of 8 mm and a lamp having no light transmitting portion were used in the same manner as in the first embodiment on the original surface. The light receiver was moved to measure the light amount distribution. The lighting conditions are also the same as in the first embodiment.

FIG. 6 is a diagram showing the above measurement results. The thick line in FIG. 6 is the illuminance distribution when a lamp having a light transmitting portion is used, and the solid line is the illuminance distribution when a lamp having no light transmitting portion is used. The horizontal axis represents the distance from the optical axis in the direction orthogonal to the lamp tube axis on the original glass, and the vertical axis represents the light quantity at each point. In FIG. 5, the lamp side and the arrowed direction are the sides where the lamp 20 is provided in FIG. As is clear from the figure, also in this embodiment, when the lamp having the light transmitting portion is used, the amount of light emitted from the irradiation unit is increased as compared with the case where the lamp having no light transmitting portion is used. The effect of this example was confirmed.

Further, the light amount distributions of the conventionally used irradiation unit for illuminating a document and the irradiation unit of this embodiment were measured, and the effect of the irradiation unit of this embodiment was confirmed. FIG. 7 is a diagram showing a configuration of a conventional document illumination irradiation unit used in conducting the comparative experiment. In the figure, 10 is the lamp shown in FIG. 9 having no light-transmitting portion on the external electrode, 23 is the original glass, and 24 is a reflecting mirror. In the irradiation unit shown in FIG. 7, the light emitted from the aperture of the lamp 10 having no light-transmitting portion is directly irradiated on the original surface on the original glass, and is reflected by the reflecting mirror 24 to be reflected on the original glass 23. The surface of the placed original is irradiated. Then, the reflected light enters the image reading means such as a CCD through the slit S provided between the lamp 10 and the reflecting mirror 24 and the optical system and the lens (not shown) as described above.

Regarding the irradiation unit shown in FIGS. 5 and 6, the length is 370 mm and the tube diameter is 8 as described above.
A φmm lamp was used to turn on the light under the same lighting conditions as above, and the light receiver was moved on the original surface to measure the light amount distribution. FIG. 8 is a diagram showing the above experimental results. The left side shows the illuminance distribution of the irradiation unit shown in FIG. 7, and the right side shows the illuminance distribution of the irradiation unit of this embodiment shown in FIG. is there.

In the figure, the horizontal axis is the distance from the optical axis in the direction orthogonal to the lamp tube axis on the original glass, and the vertical axis is the illuminance at each point (the peak illuminance of the conventional irradiation unit in FIG. 7 is 100). Relative value), and the direction indicated by the arrow on the lamp side is the lamp 2 in FIGS.
This is the side where 0 and 10 are provided. As is clear from the figure, by using the irradiation unit of the present embodiment, the illuminance on the original surface can be increased by about 1.3 times as compared with the conventional irradiation unit shown in FIG. It was confirmed that the illuminance on the original surface can be greatly improved by using the unit as compared with the conventional irradiation unit.

[0020]

As described above, in the present invention, a predetermined amount of a rare gas is sealed inside a glass tube coated with a fluorescent substance on the inner surface thereof, and at least a pair of electrodes are arranged on the outer surface of the glass tube in the tube axial direction. In an irradiation unit equipped with an external electrode type fluorescent lamp provided with an aperture for emitting light to the outside, at least a part of the electrodes is made transparent and is reflected away from the external electrode type fluorescent lamp. Since the material is arranged and at least a part of the transmitted light from the electrode is reflected by the reflective material to the irradiation area of the radiated light from the aperture, the same input power can be obtained as compared with the conventional irradiation unit. The amount of light can be increased. Therefore, for example, by applying it to a backlight device of a liquid crystal display, it is possible to obtain the same brightness as a conventional device with a small input power, and by applying it to a document reading irradiation unit of an information device. Therefore, the illuminance on the document surface can be improved, and the document reading speed can be sufficiently increased.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first irradiation unit of the present invention.

FIG. 2 is a cross-sectional view perpendicular to the tube axis of an external electrode type fluorescent lamp having a transparent portion as an electrode.

FIG. 3 is a diagram showing the shape of a translucent external electrode used in the present invention.

FIG. 4 is a diagram showing a comparative experiment result in the first example.

FIG. 5 is a diagram showing a configuration of an irradiation unit according to a second embodiment of the present invention,

FIG. 6 is a diagram showing a comparative experiment result in the second example.

7 is a diagram showing a configuration of a conventional irradiation unit used when performing the experiment of FIG.

8 is a diagram showing a measurement result of a light amount distribution of the irradiation unit shown in FIGS. 5 and 6. FIG.

FIG. 9 is a cross-sectional view perpendicular to the tube axis of a conventional external electrode type fluorescent lamp.

[Explanation of symbols]

 1 Glass Tube 2, 2'External Electrode 3 Fluorescent Material 4 Aperture 6 Translucent Part 10 External Electrode Fluorescent Lamp 11 U-shaped Reflecting Material 20 External Electrode Fluorescent Lamp with Translucent Part 21 Main Reflector 22 Sub-Reflector 23 Original glass

Claims (1)

[Claims] 1. A glass tube having a fluorescent substance coated on the inner surface thereof is sealed with a predetermined amount of a rare gas, and at least a pair of electrodes are arranged on the outer surface of the glass tube in the tube axis direction to form an aperture for emitting light to the outside. An irradiation unit comprising an external electrode type fluorescent lamp provided, wherein at least a part of the electrode is translucent, and a reflecting material is arranged apart from the external electrode type fluorescent lamp. An irradiation unit using an external electrode type fluorescent lamp, characterized in that at least a part of transmitted light from the electrode is reflected to an irradiation region of the emitted light from the aperture.