JPS62219457A - Illuminator - Google Patents

Abstract

PURPOSE:To enhance the efficiency and luminance of an illuminator, by providing a cylindrical lens at the light emission opening of a slender discharge tube in which a high-frequency voltage is applied to electrodes on the outside surface of the tube to emit light, to improve the light condensing property of the illuminator. CONSTITUTION:A cylindrical lens 20 is tightly fitted at the light emission opening 1a of the surface of a slender discharge tube 1 having electrodes 2 at both the ends of the tube and a square cross section or the like, so that an illuminator for a reader or the like for the original is constituted. A high-frequency voltage is applied between the electrodes 2 by a high-frequency voltage application means 3 to stimulate mercury vapor in the discharge tube 1 to generate ultraviolet rays to cause a fluorescent substance on the inside surface of the discharge tube to emit visible light. The light is condensed by a lens 20 to perform illumination from under a platen 10. The light condensing property of the illuminator is thus improved to enhance the efficiency and luminance thereof and lengthen the life thereof.

Description

[Detailed description of the invention] Good 1” 2 anal m balls! The present invention generally relates to a lighting device that can be used for various purposes, and more particularly to a lighting device that can be suitably used as a document reading device that illuminates a document and reads a document image in office equipment, that is, as an exposure means, etc. It is something. Hereinafter, in this specification, 1 the present invention is referred to as Office II! Although the description will be made in connection with a document reading device for a device, the use of the illumination *a according to the present invention is not limited to this device.

Conventionally, elongated fluorescent lamps, halogen lamps, and the like have been frequently used to provide an effective elongated (elongated) light amount for illumination devices such as manuscript reading devices.

Fluorescent lamps have a small amount of light and are usually used as lighting devices for low-speed office equipment.In order to use fluorescent lamps as lighting equipment for high-speed office equipment, which is currently in demand, it is necessary to increase the power supply. As the brightness (light emission amount) increases, the internal filament installed inside the fluorescent tube will melt, so there is a limit to the increase in power supply, and in reality it is unsuitable as a lighting device for high-speed office equipment. It is.

On the other hand, halogen lamps emit a large amount of light.

Although it is used for high-speed office equipment, it generates more light in the infrared wavelength range than the visible light range required for document reading by office equipment, and not only is the luminous efficiency poor, but it also produces light with wavelengths that are rejected by the office equipment. In order to reduce the heat generated by the lighting, an additional cooling device is required, and it cannot be said to be a desirable lighting device in today's world where office equipment is desired to be smaller and cheaper.

The present applicant has proposed an elongated illumination device that solves the drawbacks of the conventional fluorescent lamps and halogen lamps, and is suitable not only for -1it> illumination, but also particularly suitable for document reading devices in office equipment. 60-78782), the lighting device 1
00, as shown in FIG. 5, a discharge tube 1 that emits light by a high-frequency electromagnetic field, an electrode 2 disposed on the outer wall of the discharge tube, and a high-frequency applying means 3 that applies a high frequency to the electrode. Equipped with.

To explain further, in FIG. 5, the discharge tube l is formed by coating a phosphor inside an elongated glass tube usually made of soda glass or pyrex glass, and inside the discharge tube there is a discharge such as mercury. A starting material and an inert gas such as Ar are enclosed. Furthermore, electrodes 2 made of a conductive material, such as copper or stainless steel, which are less likely to oxidize, are disposed at or near both ends of the discharge tube l. The electrode is usually provided in close contact with the outer wall of the discharge tube, but it can also be provided slightly spaced from the outer wall of the discharge tube.

A high frequency voltage is applied to the electrode 2 by a high frequency applying means 3. The high frequency application means 3 can have any configuration, but
For example, as illustrated in FIG. 6, a high frequency oscillation circuit 4 that oscillates a high frequency voltage, an input power source 5 for the high frequency oscillation circuit 4, and amplification of the high frequency voltage from the high frequency oscillation circuit 5 to a desired voltage. and an LC coupler 7 for matching the high frequency voltage from the amplifier 2!6 with the impedance of the discharge tube l.

When a high frequency voltage is applied to the electrode 2 from the high frequency applying means 3 having such a structure, the mercury gas in the discharge tube becomes excited by the high frequency electromagnetic field.

Generates ultraviolet light. The ultraviolet rays act on the phosphor coated on the inner wall of the discharge tube to generate light in the visible light range.

FIG. 7 shows another embodiment of the illumination device, which differs from the illumination device of FIG. 5 only in the configuration of the electrodes. In other words, the electrode 2a of this example is wound in a coil shape multiple times along the longitudinal direction of the elongated discharge tube 1, which has the same configuration as the discharge tube 1 described in connection with FIG. The difference is that the high frequency applying means 3 is provided on the outer wall of the discharge tube 1, and the high frequency applying means 3 has the same structure as described in connection with FIG. The illumination device shown in FIG. 7 has the advantage of being able to apply a larger amount of power to the electrodes and obtain a larger light layer than the illumination device *a shown in FIG. 5.

In the lighting device shown in FIGS. 5 to 7 above, the electrode 2.2a is provided outside the discharge tube, and unlike conventional fluorescent lamps and halogen lamps, the lighting device does not have a filament inside the discharge tube. First, the degree of deterioration of the electrodes is extremely small, and the electrodes can be replaced once they have deteriorated, making it possible to always obtain a desired level of brightness (light 9). Furthermore, the lighting device can apply a large amount of power to the electrodes, and it is possible to increase the amount of light. Moreover, such a lighting device is
Unlike conventional halogen lamps, it does not generate high heat, has extremely good luminous efficiency, and has the advantage that there is no need to prepare a special cooling device when used in office equipment. Furthermore, since the discharge tube can be formed into a long length, such an illumination device has the advantage that it is extremely effective without causing uneven brightness across the width of the document, especially when used as a document reading device.

The above-mentioned illumination device has various advantages as mentioned above, but according to research experiments conducted by the present inventors, in order to use the light from the discharge tube more effectively, it is necessary to It is best to condense the light irradiated onto the document, and for this purpose, as shown in Figure 8, a reflective shade lO is provided at the rear of the discharge tube l so that the light is converged onto the original from the light irradiation aperture section 1a in front. It is configured as follows. However, the shape of a reflective shade is an important factor that determines its light-condensing characteristics, and for this reason, it is necessary to manufacture it with extremely high dimensional accuracy, surface properties, surface reflectance, etc., making it difficult to manufacture and difficult to manufacture. This made the cost high.

As a result of conducting many research experiments in order to solve such problems, the inventors of the Wood Company and others have found that the discharge tube 1 of the lighting device having the configuration illustrated in FIGS. 5 to 7 can be processed into any shape. The present invention was developed by paying attention to this advantage.

An object of the present invention is to provide a high-intensity, long-life lighting device that has good light-gathering properties and can illuminate a target object with high efficiency.

Another object of the present invention is to provide a high-intensity, long-length discharge tube equipped with an elongated discharge tube that emits light by a high-frequency electromagnetic field, which can be suitably used in a document reading device of office equipment such as an electrophotographic copying device. Our goal is to provide lighting equipment with a long lifespan.

Point U: The above object is achieved by the lighting device according to the present invention. To summarize, the present invention provides a lighting device comprising an elongated discharge tube that emits light by a high-frequency electromagnetic field, an electrode disposed on the outer wall of the discharge tube, and a high-frequency applying means for applying a high frequency to the electrode. , an illumination device characterized in that a cylindrical lens is disposed integrally with the light irradiation aperture portion of the discharge tube, in close contact with the aperture portion, or in close proximity to the aperture portion.

Next, the illumination device according to the present invention will be described in more detail, taking as an example the case where the illumination device according to the present invention is used as a document reading device, that is, an exposure means, of an electrophotographic copying device.

Referring to FIGS. 1 and 2, an example of the illumination device 100A according to the present invention disposed below the document storage table lO is illustrated. According to the present invention, the illumination device filoOA is shown in FIG. In this embodiment, a cylindrical lens 20 is disposed on one surface of a discharge tube 1 having electrodes 2 at both ends, that is, a light irradiation aperture portion 1a, as shown in FIG. The cross-sectional shape is rectangular, and therefore the cylindrical lens 20 is disposed in close contact with the light irradiation aperture portion 1a, which is one plane of the discharge tube. Of course, the cylindrical lens 20 can also be provided close to the light irradiation aperture portion 1a with a slight gap therebetween. In either configuration, it is preferable that the discharge tube l and the cylindrical lens 20 are integrally configured by appropriate mounting means 1, such as a tightening band or adhesive.

Further, the cross-sectional shape of the discharge tube 1 is not limited to a rectangular shape, but can be any shape depending on the purpose. Furthermore, the cylindrical lens and the seven perforations may be integrally molded.

Further, as shown in FIG. 3, a conductive thin layer 11922 is provided between the cylindrical lens 20 and the light irradiation aperture portion 1a of the discharge tube, so that the high frequency electromagnetic waves applied to the discharge tube by the high frequency application means are It is preferable to prevent the light from leaking to the outside from the light irradiation aperture portion 1a and causing noise in a microcomputer or the like used to control the copying apparatus. As the conductive material 11922, tin oxide ms, conventionally known as Nesa Glass, is suitable, and it is preferably bonded to the cylindrical lens side with a thickness of several tens to several thousand sq.

With the above configuration according to the present invention, the light emitted from the discharge tube l through the light irradiation aperture portion 1a is focused by the cylindrical lens 20 onto the document surface on the document table.

In the above embodiment, the illumination device 100A has the opposite electrode configuration as shown in FIG. 5, but as shown in FIG. 4, the same electrode configuration as described in connection with FIG.
Similar effects can be achieved.

Furthermore, to explain the lighting device of the present invention more specifically,
In the L tube l, the width of the light irradiation aperture part 1a is 30 mm, the thickness of the discharge tube l is 2 cm, and the length is 300 mm, and several Torr of Ar is added inside the discharge tube, and Hg is added as a discharge initiator.
In a discharge tube having the configuration shown in Fig. 2, which is manufactured by enclosing
z-10"Mn2.M, pressure is 200V or more at vpp,
A high frequency voltage with a high frequency pulse duty ratio of 5 to 90% is applied to achieve good lighting.

Also, as a cylindrical lens, the focal length is 50mm.
I used the one from When such an illumination device was used, the light intensity on the irradiated surface of the document was significantly improved.

11 Tatewaj The illumination device according to the present invention configured as described above can be suitably used not only for general illumination but also particularly for document reading devices of office equipment such as electrophotographic copying devices. It is equipped with an elongated discharge tube, has good light gathering ability, can illuminate a target object with high efficiency, and has the features of high brightness and long life. Furthermore.

There is no need for a reflective shade, and the device can be made more compact.

[Brief explanation of drawings]

FIG. 1 is a side view of an embodiment of the illumination device according to the present invention, showing a mode in which it is used for document illumination. 2 is a perspective view of the illumination device of FIG. 1; FIG. FIG. 3 is a side view of another embodiment of the lighting device according to the present invention. FIG. 4 is a perspective view of another embodiment of the lighting device according to the present invention. FIG. 5 is a front view of an embodiment of a lighting device having a discharge tube. FIG. 6 is a circuit block diagram of high frequency application means used in the illumination device of FIG. 5. FIG. 7 is a front view showing another example similar to FIG. 5. FIG. 8 is a perspective view of a lighting device with a reflective shade. l: Discharge tube la: Light irradiation aperture 2.2a: Electrode 3: High frequency application means 20 Nijirintorical lens 22 Knee 4-electric thin film 3rd design 4 t)
7Figure 7 2 1a

Claims (1)

[Claims] 1) An elongated discharge tube that emits light by a high-frequency electromagnetic field;
In a lighting device comprising an electrode disposed on the outer wall of the discharge tube and a high frequency applying means for applying a high frequency to the electrode, the lamp is integrally formed with the light irradiation aperture of the discharge tube or is closely attached to the aperture. An illumination device characterized in that a cylindrical lens is disposed at or near the light irradiation aperture. 2) The lighting device according to claim 1, wherein a conductive thin film is formed on either the surface of the light irradiation aperture portion or the surface of the cylindrical lens facing the light irradiation aperture portion. 3) The lighting device according to claim 2, wherein the conductive thin film is a tin oxide thin film. 4) The illumination device according to claim 1, 2, or 3, wherein the surface of the light irradiation aperture portion is a flat surface.