JPS6358796A - Lighting device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 3.Details of the Invention rj;t "5'1 -F11 The present invention generally relates to a lighting device that can be used for various purposes, and in particular to This invention relates to an illumination device that can be suitably used as an exposure means, etc., for illuminating a document and reading out an image of the document. Although described in connection with a reading device, the use of the illumination device according to the present invention is not limited to this device.

' Long length (slender shape) that is effective as a lighting device for document reading station, etc.
As a light source, elongated fluorescent lamps, halogen lamps, etc. are frequently used.

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 aircraft, which has recently been in demand, the power supply has been increased. As the brightness (emission light?) 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 not suitable as a lighting device for high-speed equipment. Not suitable.

Electric power and halogen lamps emit a large amount of light and are used for high-speed office equipment, but they emit more light with wavelengths in the infrared range than the visible light range required for reading documents in office equipment. Not only is the luminous efficiency poor, but the heat generated by such wavelengths is large, and the cooling device 2 is used to reduce this heat generation effect. , 45 requires a large cooling system, and it is desired that the aircraft base be made smaller and lower in price.

The present applicant has proposed an elongated illumination device which solves the drawbacks of conventional fluorescent lamps and halogen lamps and is suitable not only for general illumination but also particularly as a document reading device for the Tatsumi Aircraft Base (patent application As shown in FIG. 3, the illumination ma1100 includes a discharge tube 1 that emits light by a high-frequency electromagnetic field, and a coil-like structure that is coiled multiple times along the longitudinal direction of the elongated discharge tube l. The discharge tube 1 is provided with an electrode 2 which is wound around the outer wall of the discharge tube 1, and a high frequency application means 3 which supplies high frequency power to the electrode.

To explain further, in FIG. 3, 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. R3J4 wood and a non-conductive gas such as Ar are sealed. A high frequency voltage is applied to the recording pole 2 by a high frequency applying means 3. The high frequency electromagnetic field VJt3 may have any configuration, but as illustrated in FIG. 4, for example, it includes a high frequency oscillation circuit 4 that oscillates a high frequency voltage, and an input power source 5 for the high frequency oscillation circuit 4.

It has an amplifier 6 for amplifying the high frequency voltage from the high 15 wave oscillation circuit 5 to a predetermined voltage, and an LC coupler 7 for matching the high frequency voltage from the amplification=6 with the impedance of the discharge 71.

When a high frequency voltage is applied to the electrode 2 from the first stage 3 of high frequency application configured as described above, the mercury gas inside the discharge tube is exposed to the high frequency 'W! , becomes excited by a magnetic field and 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. 5 shows another embodiment of the illumination device, but the illumination device shown in FIG. The devices differ in the configuration of the electrodes. In other words, the electrodes 2a of this example are made of a conductive material such as copper or stainless steel, which is less oxidized, in the vicinity of both ends of the elongated discharge tube l, which has the same configuration as the discharge tube l explained in connection with FIG. The electrode is a ring-shaped plate electrode having a length of 41'. Although the electrode can be provided slightly apart from the outer wall of the discharge tube, it is usually preferable to provide the electrode in close contact with the outer wall of the discharge tube because the power loss applied to the discharge tube is small.

In the lighting device shown in FIGS. 3 to 5 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 amount). Furthermore, such a light source 121 can apply a large amount of power to the electrodes, making it possible to increase the light intensity. Also, such lighting 9
21 does not generate high heat like conventional halogen lamps, has extremely good luminous efficiency, and is
When used at 6th base, etc., it is only necessary to install a small cooling device, and in some cases there is an advantage that there is no need to prepare a special cooling device. Furthermore, such lighting? t21
Since the discharge tube is formed in a long length, it has a feature that it is extremely effective, especially when used as a document reading device, since uneven illumination does not occur across the document width direction.

Although the above-mentioned lighting device has various advantages as mentioned above, according to research experiments conducted by the present inventors, it was found that there is a drawback that stable lighting cannot be obtained at the time of initial lighting. In other words, the initial lighting is very unstable, and it may not turn on at all, or it may stay on for a long time. Phenomena such as only half of the light being lit may occur. Alternatively, it may take quite a long time, for example, 6 to 10 seconds, to turn on the light.

The inventors of the present invention have conducted many research experiments in order to solve such problems, and as a result, we have provided auxiliary electrodes at both ends of the discharge tube separately from the F soil electrode 2.2a of the discharge tube. It has been found that when lighting the discharge tube, by supplying a predetermined amount of power that is less than the lighting power to the discharge tube through the auxiliary electrode in advance, the initial lighting of the discharge tube can be achieved extremely quickly and stably. . This is because the electrons and atoms of the discharge initiator sealed inside the discharge tube, such as mercury and non-monotypic scum, start to vibrate when power is supplied through the sub-electrode, and the lighting state E is not reached. This is thought to be due to the fact that the mercury in the discharge tube immediately enters a fully excited state of 1'J when high-frequency power for discharge is supplied to the main electrode of the discharge tube. .

In other words, by supplying preliminary power to the discharge tube during lighting, even if there is an impedance difference between the impedance on the load side (discharge tube side) and the impedance on the drive side (LC coupler side). This is thought to be because it becomes possible to stably start the training even if

The present invention has been made based on this new knowledge.

An object of the present invention is to provide a high-intensity, long-life lighting device that can achieve stable and reliable initial lighting.

Another object of the invention is, in particular, to
It is equipped with a preferably elongated discharge tube that emits light using a high-frequency electromagnetic field, and can be suitably used in a document reading device of fG office equipment such as '3, and achieves stable and reliable initial lighting in an extremely short time. Therefore, it is an object of the present invention to provide a lighting device with a short rise time, high brightness, and a long life.

The above objects are achieved by the lighting device according to the present invention. In summary, the present invention provides a discharge tube that emits light by a high-frequency electromagnetic field, a main electrode disposed on the outside of the discharge tube, sub-electrodes disposed on both external ends of the discharge tube, and the main electrode. and a high-frequency applying means for applying a high-frequency electromagnetic field to the discharge tube via a sub-electrode, for supplying a predetermined power to the sub-electrode prior to supplying power to the main electrode when lighting the discharge tube. The illumination device is characterized by comprising a control means for controlling supply of power from the high frequency application means to the main electrode and the sub-electrode.

Support j Next, the lighting device according to the present invention will be described in more detail with reference to the drawings.

Referring to FIG. 1, an embodiment of the lighting device according to the present invention is shown, and in this embodiment, the configuration of the discharge tube l and the electrode 2 of the lighting device Wl100A is the same as that of the discharge tube l described in connection with FIG. and has the same configuration as electrode 2. Let me explain in more detail by giving an example.

When the discharge tube has a diameter of 5 to 30 mm and a length of 300 mm, the discharge tube with the configuration shown in FIG. When the main electrode 2 is in the normal lighting state, a high frequency voltage is applied from the high frequency applying means 3 with a frequency of 8M1 (z NI OM Hz, a voltage of 200 V or more at VPP, and a high frequency pulse duty ratio of 5 to 90%). and good lighting is achieved.

However, when such a lighting device is used, at the time of initial lighting, the same voltage VPP as in the lighting state is applied to the main electrode 2.
If -cn 8 MHz and 10 MHz were supplied, only half of the discharge tube would light up, and it would not be possible to light it up completely.

According to the final chapter 11, as illustrated in FIG.

In addition to the main electrode 2, there are plate-shaped sub-electrodes 1 on the outer periphery of both ends of the discharge tube l.
0 is placed. The sub-electrode 10 is made of a conductive material that is less likely to oxidize, such as copper or stainless steel. The sub-electrode 1O can be provided over the entire end area of the discharge tube l, but as shown in FIG. can be changed in various ways depending on the size, shape, etc. of the discharge tube. Moreover, the sub-electrode lO is
Although it can be provided slightly apart from the outer wall of the discharge tube, it is usually preferable to provide it in close contact with the outer wall of the discharge tube because the power loss applied to the discharge tube is small.

In the above explanation, the main electrode 2 is a coil-shaped main electrode 2 formed by winding it several times around the outer circumference of the discharge tube as explained in connection with FIG. 3, but the structure shown in FIG. It is also possible to take other shapes.

As illustrated in FIG. 2, the main electrode ? and sub-electrode 1
The high-frequency applying means 3 for supplying high-frequency power to the main electrode 1 is roughly the same as the means explained in connection with FIG. In order to supply a predetermined power to the sub-electrode 10 prior to this, a control means 20 is provided to control the supply of power from the high-frequency applying means 3 to the main electrode 2 and the sub-electrode IO. According to this embodiment, the control means 20 includes, for example, a microprocessor 2i and a switching element 22 which is driven and controlled by the microprocessor 21 and which switches the power supply between the main electrode 2 and the sub-electrode 10. The main electrode is also controlled by the microprocessor 21 for 4 hours.
and a power fluctuation factor driving means 23 that acts on a high frequency oscillation circuit or the like to vary the magnitude of the power supplied to the sub-electrode IO, and drives and controls the power fluctuation factor of the circuit.
and.

In the lighting device 100A having the above configuration, prior to one lighting, the switching element 22 is driven by the microprocessor 21 of the control means 20, and the contacts C and a are connected in FIG. Ru. at the same time,
The microprocessor 21 drives the power variation factor driving means 23 to operate the high frequency application means 3, that is, the high frequency oscillation circuit 3 in this embodiment, so that a predetermined power is supplied to the sub-electrode IO. As a result, preliminary high-frequency power is supplied to the discharge tube prior to lighting, and therefore the atoms and electrons of mercury and Ar gas within the discharge tube repeatedly vibrate and become in a preliminary excited state, and the discharge tube is in the state immediately before starting discharge. becomes.

Next, when the lighting signal is transmitted, or automatically after a predetermined period of time has elapsed after power is supplied to the sub-electrode IO, the microprocessor of the control means 20 is activated, the switching element 22 is driven, and the main electrode 2 is actuated. In order to establish this state, contacts C and a are opened in FIG. 1, and contacts c and b are connected. At the same time, the microprocessor 21 drives the power fluctuation factor driving means 23, so that the main electrode 2 is supplied with a predetermined power for lighting the discharge tube. Activate. As a result, mercury and Ar, which have been preliminarily brought into an excited state, are brought into a completely excited state, and the discharge tube 1 is immediately lit. As understood from the above explanation, when power is supplied to the main electrode 2, the supply of power to the sub-electrode 10 is stopped, but power is continuously supplied to the sub-electrode 10 for a predetermined period of time. It is also possible to continue.

For example, when the diameter of the discharge tube is 5 to 30 mm and the length is 300 mm as described in L, several Torr of Ar is applied inside the discharge tube.
In the illumination 9m using the discharge tube l having the configuration shown in FIG. lOMHz, voltage 10 at Vpp
A high frequency power of 0 V or more and a high frequency pulse duty ratio of 5 to 90% is applied, and the sub electrode 10 is supplied with a frequency of 10 Hz to 10 Hz from the high frequency applying means 3.
A good lamp is constructed by applying high frequency power with a voltage of 20 V or more at Vpp and a high frequency pulse duty ratio of 5 to 95%. In other words, unreleased 1
4, the power supplied to the sub-electrode 1o is preferably 10 to 50% of the power supplied to the main electrode 2.

Book lighting! When the A21 is used in a document reading device such as a copying machine, a normal copying operation is performed after the illumination device is turned on as described above. When the copy operation is completed, the high frequency application means is also turned off. If a copy operation is to be performed continuously, the illumination device supplies main electrode preliminary power and then applies power to the main electrode. The discharge tube may be lit by supplying power, but when the discharge tube is turned off for a short time, such as in continuous copying, the step of supplying power to the sub-electrode can be omitted.

The power fluctuation factor driving means 23 of the control means 20 can be configured to control any one or any combination of the high frequency voltage, duty ratio, and frequency in the high frequency oscillation circuit 4.

In the above description, power is supplied to the main electrode 2 and the sub-electrode 10 by using one high-frequency application means 3, and by controlling the power fluctuation factor of the means, two types of high-frequency power are generated and supplied to each. Although it was explained as
It is also a circuit to provide two types of high frequency application means, one for the main electrode and one for the sub electrode, and to supply a predetermined power to each electrode by switching with a switching element.

The lighting device according to the present invention configured as described above is suitable for use not only in general lighting but also in document reading devices of office equipment such as electrophotographic copying machines. It is equipped with a discharge tube that is preferably elongated and has the characteristics of being able to achieve stable and reliable initial lighting, short turn-down time, and furthermore, high brightness and long life. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a lighting device according to the present invention. FIG. 2 is a block diagram showing the high frequency application means and control means. FIG. 3 is a schematic diagram of the conventional illumination type. FIG. 4 is a block diagram showing an example of conventional high frequency application means. FIG. 5 is another schematic configuration diagram of the conventional illumination type δ. l: Discharge tube 2.2a: Main electrode 3: High 14 wave application means 10: Sub-electrode 20: Control means 21: Microprocessor 22 Niswitching element 23: @Force fluctuation factor driving means Fig. 2 73

Claims (1)

[Scope of Claims] 1) A discharge tube that emits light by a high-frequency electromagnetic field, a main electrode disposed on the outside of the discharge tube, sub-electrodes disposed on both external ends of the discharge tube, and the main electrode. high frequency applying means for applying a high frequency electromagnetic field to the discharge tube via an electrode and a sub-electrode;
When lighting the discharge tube, the supply of high-frequency power from the high-frequency applying means to the main electrode and the sub-electrode is controlled so as to supply a predetermined high-frequency power to the sub-electrode prior to supplying high-frequency power to the main electrode. A lighting device comprising: a control means for controlling the lighting device; 2) The lighting device according to claim 1, wherein the high frequency power supplied to the sub-electrode is 10 to 50% of the high frequency power supplied to the main electrode. 3) The lighting device according to claim 1 or 2, wherein the main electrode is a coiled electrode arranged around a discharge tube. 4) The lighting device according to claim 1 or 2, wherein the main electrode is an annular electrode arranged near both ends of the discharge tube and wound around the outer periphery of the discharge tube. 5) The lighting device according to any one of claims 1 to 4, wherein the auxiliary electrode is a plate-shaped electrode attached to the outer periphery of both ends of the discharge tube. 6) The lighting device according to any one of claims 1 to 5, wherein the high-frequency power to the sub-electrode is stopped after the discharge tube is lit.