JP2971802B2 - Rare gas discharge lamp device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare gas discharge lamp device, and more particularly to a facsimile, an image scanner, and a copy machine.
The present invention relates to an improvement in an insulation treatment structure of a rare gas discharge lamp device applied to a document irradiation device in an OA device such as a printer.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 7, a document irradiating device irradiates a document surface P with radiation light from a discharge lamp A and reflects light reflected from the document surface P as a CCD device (charge coupled device). The linear sensor-S is configured to receive light.

[0003] As a discharge lamp A applied to this device,
Electrodes are arranged at both ends of a glass bulb having a light emitting layer made of a phosphor on the inner wall, and a predetermined amount of mercury and argon gas are sealed in the interior space of the glass bulb. Mainly 253.7n
Since the light emitting layer is excited by m), the illuminance on the document surface P can be increased.

[0004] However, in the discharge lamp A, although excellent light output characteristics can be obtained in a steady state as described above,
It takes a long time from turning on until reaching a steady state.
This is because it takes a relatively long time for the mercury vapor in the glass bulb to transition to the stable state, during which the light output is not stable.

In the document irradiating device, the document is read simultaneously with the operation of the device. Therefore, the document irradiating device is immediately turned on in accordance with the operation state of the device, and its light amount is more than a predetermined light amount, for example, 100% in a very short time. Although it is required that the discharge lamp A uses a mercury-argon gas, the reading accuracy is significantly impaired due to insufficient illuminance at the initial lighting.

[0006] In addition, the mercury vapor pressure in the glass bulb varies with changes in ambient temperature and the light output also varies. For this reason, if the temperature of the portion where the document irradiating device is installed fluctuates, the illuminance of the document surface P greatly fluctuates with the fluctuation of the light output of the discharge lamp A, and the reading accuracy of the document becomes poor. Will be damaged.

Incidentally, various proposals have been made to solve such a problem. For example, an attempt has been made to apply a rare gas discharge lamp using a rare gas containing xenon gas as a main component instead of the mercury-argon gas of the discharge lamp.

According to this rare gas discharge lamp, since no mercury is used, the rise of the light output after lighting is steep, almost reaches the set value almost at the same time of lighting, and the light output and the starting voltage. Is suitable for use as a light source for irradiating a document of an OA device because it is hardly affected by the ambient temperature.

However, in this rare gas discharge lamp, since the rare gas is sealed in the glass bulb at a high pressure of tens to hundreds of torr, the diameter of the positive column during operation is reduced, and the inside of the glass bulb is reduced. Tends to be unstable in the discharge position. For this reason, there is a problem that unevenness occurs in brightness and that the illuminance distribution in the axial direction of the glass bulb is difficult to be uniform.

A rare gas discharge lamp as disclosed in Japanese Patent Application Laid-Open No. 62-281256, for example, has also been proposed. In this discharge lamp, a pair of electrodes is arranged at an end portion inside a glass bulb having a light emitting layer on an inner wall, and a band-shaped auxiliary electrode is arranged on an outer wall of the glass bulb corresponding to between the electrodes, and Is filled with a rare gas at a high pressure of 90 to 110 torr.

According to this discharge lamp, a high frequency high voltage is applied to a pair of electrodes in a state in which a predetermined potential is applied to the auxiliary electrode (for example, in a state of being grounded). Since the column portion is uniformly deviated toward the auxiliary electrode, the position of the positive column in the glass bulb is stabilized, and the illuminance distribution in the axial direction of the glass bulb can be made relatively uniform.

However, in this discharge lamp, the discharge generated between the pair of electrodes starts to be deviated to the auxiliary electrode side from a part slightly separated from the electrodes, and the discharge generated in the positive column is almost deviated to the auxiliary electrode side. Although the illuminance distribution in the axial direction of the glass bulb in the positive column is almost uniform, the excitation of the light emitting layer around the pair of electrodes is insufficient. Smaller than the part. Therefore, since the illuminance distribution in the entire axial direction of the glass bulb cannot be made uniform, when this discharge lamp is applied to an original irradiating device, only the effective light emitting portion corresponding to the positive column can be used, and the OA equipment is small. There is a problem that it becomes an obstacle in the development.

[0013]

SUMMARY OF THE INVENTION Accordingly, the applicant has
First, in order to solve such a problem, a rare gas discharge lamp 1 shown in FIGS. 4 and 5 has been proposed.

The rare gas discharge lamp 1 is configured as follows, for example. In the figure, reference numeral 2 denotes an elongated glass bulb, on the inner wall of which a light emitting layer 3 made of a phosphor is formed. In the light emitting layer 3, for example, a light projection window 3a in which no light emitting layer is formed is formed over substantially the entire length of the glass bulb. Disc-shaped sealing glasses 4a and 4b are hermetically sealed to the end of the glass bulb 2. The interior space of the glass bulb 2 is filled with a rare gas containing, for example, xenon gas as a main component. Terminals 6a and 6b are formed on the end surfaces of the sealing glasses 4a and 4b, for example, by bending and extending a part of the ends of the external electrodes 5a and 5b. Lines 7a and 7b are connected. Further, a pair of strip-shaped external electrodes 5a and 5b are arranged on the outer wall of the glass bulb 2 so as to be spaced apart from each other and to face each other over substantially the entire length thereof. In particular, the external electrodes 5a and 5b
It is made of an opaque metal member having excellent conductivity like aluminum foil, and is arranged on the outer wall so that the light projection window 3a is not substantially closed.

The rare gas discharge lamp 1 thus configured is
For example, it is turned on by the lighting device shown in FIG. In the figure, INV is an inverter circuit for converting a DC converted from an AC power supply E into a high-frequency high voltage, and its output side is connected to the external electrodes 5a and 5b of the rare gas discharge lamp 1. In this state, a high-frequency high voltage (for example, 20 to 100 KHz, 1000 to 2000 V) is applied between the external electrodes.
Is applied to generate a discharge in the rare gas. As a result, the light emitting layer 3 is excited to emit light, and is projected from the light projection window 3a to the outside.

According to the rare gas discharge lamp 1, a pair of external electrodes 5a, 5a,
5b are merely spaced apart from the glass bulb 2
Since no electrodes are arranged inside the glass bulb 2, a discharge is generated uniformly in any part in the axial direction inside the glass bulb 2 and light is emitted uniformly. Therefore, the light projected from the light projection window 3a is equalized over substantially the entire length of the glass bulb 2, and when applied to a document irradiating device, the reading quality of the document can be improved.

Moreover, since the light projection window 3a can be set to a length substantially equal to the entire length of the glass bulb 2, the ratio of the length (effective emission length) of the light projection window 3a to the entire length of the glass bulb is the same as that of the prior art. The size can be greatly expanded as compared with the case where a pair of electrodes are arranged in a glass bulb as shown in FIG. Therefore,
For example, when used for reading an A4 size document, a rare gas discharge lamp having substantially the same length as the width of the document is sufficient, so that an effect such as further downsizing of the OA equipment can be expected.

However, this rare gas discharge lamp 1 is OA
When incorporated into a device, it is fixed by supporting the end thereof. However, since the high frequency high voltage is applied to the external electrodes 5a and 5b, the high voltage at the end of the discharge lamp is fixed. It is necessary to ensure sufficient electrical insulation between the external electrodes 5a, 5b and the terminals 6a, 6b, which are charging portions, and the OA equipment, and appropriate insulation treatment is required.

Therefore, an object of the present invention is to provide a rare gas discharge lamp device that can reliably insulate a high-voltage charging section at the end of a glass bulb with a relatively simple structure and that can be easily incorporated into applicable equipment. To provide.

[0020]

SUMMARY OF THE INVENTION Accordingly, in order to achieve the above-mentioned object, the present invention provides a glass bulb having a light-emitting layer on the inner wall, and a pair of strip-shaped external electrodes disposed on the outer wall of the glass bulb over substantially the entire length thereof. A terminal is provided at an end of the glass bulb so as to have an electrical connection with an external electrode, and an insulating protective layer is provided over substantially the entire length of the glass bulb outer wall.
A rare gas discharge lamp formed so as to cover the external electrode and enclosing only a rare gas containing no metal vapor such as mercury in the internal space of the glass bulb, and an end portion of the rare gas discharge lamp An insulating cap mounted so as to cover the protective layer and the terminal of the part, and an adhesive was injected into the cap so that the cap and the rare gas discharge lamp were mechanically coupled. And the second invention of the present invention is:
A lead wire is connected to the terminal and led out of the cap.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. The same parts as those in the prior art shown in FIGS. 4 to 7 are denoted by the same reference numerals, and detailed description thereof will be omitted. In this figure, the main feature of the present embodiment is that the insulating protective layers 8 and 9 are formed over substantially the entire length of the outer wall of the glass bulb so as to cover the external electrodes 5a and 5b. Insulating caps 10 and 10 are provided at the ends of the rare gas discharge lamp 1 in which only a rare gas containing no metal vapor such as mercury is sealed in the internal space, and protective layers 8 and 9 and terminals 6a and 6b is mounted so as to be covered, and the adhesives 11, 11 are placed in the cap.
That is, the caps 10 and 10 and the rare gas discharge lamp 1 are injected so as to be mechanically connected.

Spaces 10a, 10a capable of accommodating the ends of the rare gas discharge lamp 1 are formed inside the caps 10, 10, and holes 10b, 10b are formed on the back surfaces thereof. In particular, holes 10a, 10a of caps 10, 10 into which the ends of glass bulb 2 are inserted, have holes 10a.
b, 10b to adhesive 1 such as epoxy or silicone resin
1 and 11 are injected and hardened, whereby the end portions between the external electrodes 5a and 5b and the terminals 6a and 6b are covered with a cap and an adhesive, so that the charging section is properly insulated. In addition, the space 10 of the cap 10, 10
The protective layers 8 and 9 are formed at the ends of the glass bulb 2 inserted into the glass bulb 2a and 10a.
Since the parts 0 and 10 are made of plastic, the bondability between the adhesives 11 and 11 injected into the spaces 10a and 10a of the caps 10 and 10 is improved, and the mechanical connection can be improved. .

Another feature of the present embodiment is that the first protective layer 8 and the second protective layer 9 are laminated on the outer peripheral surface of the glass bulb 2. The first protective layer 8 is made of, for example, an insulating varnish such as a silicone resin, and is formed so as to cover the surfaces of the external electrodes 5a and 5b and the outer wall of the glass bulb 2 between the external electrodes. Note that the first protective layer 8 can be left in a liquid state. The second protective layer 9 is made of a transparent and heat-shrinkable tube such as a polyester resin, for example, and is formed by being laminated on the first protective layer 8.

In particular, the first and second protective layers 8 and 9
For example, it is formed as follows. First, the external electrodes 5a and 5b are arranged on the glass bulb 2, and the leads 7a and 7b are connected to the terminals of the sealing glasses 4a and 4b. Then, the lead wires 7a and 7b are immersed in a silicon resin tank, pulled up and dried. Thus, a first protective layer 8 is formed. Next, glass bulb 2
After covering with a heat-shrinkable tube, it is inserted into an oven or the like and heated. Then, the heat-shrinkable tube is heat-shrinked and adheres to the glass bulb, the external electrode, etc., and the second protective layer 9 is formed on the first protective layer 8. Note that either one of the first and second protective layers 8 and 9 can be omitted.

According to this embodiment, the insulating caps 10, 10 are provided at the ends of the rare gas discharge lamp 1 with the terminals 6a, 6b.
When the rare gas discharge lamp 1 is incorporated in OA equipment, the insulating cap 1
By using 0 and 10, it is possible to easily assemble while maintaining sufficient insulation. In addition, protective layers 8 and 9 are formed at the ends of the glass bulb 2 inserted into the spaces 10a and 10a of the caps 10 and 10, and the caps 10 and 10 are made of plastic. In relation to the space portions 10a, 1 of the caps 10, 10,
The bonding property of both of the adhesives 11, 11 injected into Oa is improved, and the mechanical bonding can be improved. In particular, caps 10 and 10 are attached to the ends of the glass bulb 2, and the adhesives 11 and 11 are injected between the two. Moisture does not easily enter between the glass bulb 2 and the glass bulb 2, and the insulation between the external electrodes 5a and 5b at the ends can be sufficiently maintained.

The outer peripheral surface of the glass bulb 2 has first and second
Of the OA equipment near the rare gas discharge lamp 1 because of the insulation protection provided by the protective layers 8 and 9, there is sufficient electrical insulation between these parts. Nature can be secured. Therefore, the size of the OA equipment can be further reduced.

In addition, the external electrodes 5a,
5b is made of a thin metal member such as an aluminum foil and has a low mechanical strength, but its outer peripheral surface is formed on a second protective layer 9 made of a heat-shrinkable tube. As a result, the mechanical strength can be effectively improved, and damage due to a small external force or impact can be prevented.

It should be noted that the present invention is not limited to the above-described embodiment, and for example, the terminal may be provided only at one end of the glass bulb.

[0029]

As described above, according to the present invention, since the insulating cap is attached to the end of the rare gas discharge lamp so as to cover the protective layer and the terminal at the end, When a rare gas discharge lamp is incorporated in an OA device, it can be easily fixed while maintaining sufficient insulation by using an insulating cap. In addition, since a protective layer is formed on the end of the glass bulb inserted into the space of the cap and the cap is made of plastic, the adhesive injected into the space of the cap is used. Can be improved, and the mechanical connection can be improved. In particular, since a cap is attached to the end of the glass bulb and an adhesive is injected between the two, moisture enters between the protective layer and the glass bulb from the end of the protective layer on the end face of the glass bulb. And the insulation between the external electrodes at the ends can be sufficiently maintained.

Furthermore, since the outer peripheral surface of the glass bulb is insulated and protected by a protective layer over substantially the entire length thereof, the components of the OA equipment exist near the rare gas discharge lamp. However, sufficient electrical insulation can be ensured between these components. Therefore, the size of the OA equipment can be further reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing one embodiment of a rare gas discharge lamp according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view of a main part showing one embodiment of the present invention.

FIG. 4 is a partially broken side view showing a rare gas discharge lamp which is a premise of the present invention.

FIG. 5 is a sectional view taken along line YY of FIG. 1;

FIG. 6 is a lighting circuit diagram of a rare gas discharge lamp.

FIG. 7 is a schematic view of a conventional document irradiation apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rare gas discharge lamp 2 Glass bulb 3 Light emitting layer 3a Light projection window 5a, 5b External electrode 6a, 6b Terminal 7a, 7b Lead wire 8, 9 Protective layer 10 Cap 10a Space 10b Hole 11 Adhesive

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Katsumi Enari (56) References JP-A-61-185857 (JP, A) JP-A-2-60046 (JP, A) JP-A-2-54160 (JP, U) Actually open sho 59-12465 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 65/00

Claims (2)

(57) [Claims] 1. A pair of strip-shaped external electrodes are arranged on the outer wall of a glass bulb having a light-emitting layer on the inner wall over substantially the entire length of the glass bulb, a terminal is provided at an end of the glass bulb, and an electrical connection with the external electrode is provided. A rare gas containing no metal vapor such as mercury in the inner space of the glass bulb, and an insulating protective layer formed so as to cover the external electrodes over substantially the entire length of the outer wall of the glass bulb. A rare gas discharge lamp encapsulating only the rare gas discharge lamp, and an insulative cap attached to the end of the rare gas discharge lamp so as to cover the protective layer and the terminal at the end portion. A rare gas discharge lamp device, wherein an adhesive is injected so as to mechanically couple the cap and the rare gas discharge lamp. 2. The rare gas discharge lamp device according to claim 1, wherein a lead wire is connected to the terminal and is led out of the cap.