JPH11176384A - Flash discharge tube and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability of luminescence without raising the minimum luminous voltage to permit continuous luminescence and increase of light quantity as well, by, controlling a coating ratio of translucent filling material by transparent conductive film within a specific range. SOLUTION: A flash discharge tube 10 is structured by sealing a cathode electrode 14 and anode electrode 16 in both end parts of a glass tube 12, and xenon gas 20 is sealed in the glass tube 12. The flash discharge tube 10 is immersed in a bath filled with solution of organic metal compound with the cathode electrode 14 facing downward up to a position where the anode electrode 16 is not immersed, in order to paint coating film 22 of the solution on the flash discharge tube 10. It is then baked at about 60 deg.C after drying. In addition, the coating film 22 of the flash discharge tube 10 is removed by immersing it in hydrochloric acid solution of one normal, and only coating film 22 in a heated part near the cathode electrode 14 is left, Thereby, a coating ratio of translucent filling material by transparent conductive film 22 is kept within a range of 5-30%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash discharge tube used for photographing and the like, in which a trigger electrode made of a transparent conductive film is formed on the surface of a light-transmitting seal made of a material such as glass. It relates to the manufacturing method.

[0002]

2. Description of the Related Art Conventionally, a flash discharge tube used for photographing or the like has a columnar glass filled with a rare gas such as xenon, and a cathode electrode and an anode electrode are provided at both ends of the glass. A trigger electrode made of a transparent conductive film mainly containing tin oxide or the like is formed on the surface.

As a means for improving the luminous efficiency of this type of flash discharge tube, the present applicant has first applied a non-coating of a transparent conductive material to all or most of the side of the flash discharge tube directly facing the subject. Proposing technology to form the part
No. 0-140065). In the flash discharge tube according to the present invention, it is shown that, for example, the light amount when only the back surface of the discharge tube is coated with the transparent conductive material is increased by about 7% as compared with the light amount when the entire surface is coated.

[0004]

The present invention is based on the results of further diligent studies by the present applicant on the relationship between the coating conditions of the transparent conductive material and the luminous efficiency in connection with the above-mentioned technology. , While providing sufficient light,
An object of the present invention is to provide a flash discharge tube excellent in light emission reliability and a method for manufacturing the same.

[0005]

A flash discharge tube according to the present invention is a flash discharge tube in which a trigger electrode made of a transparent conductive film is formed on the surface of a light-transmitting envelope. It is characterized in that the covering ratio of the optical envelope is in the range of 5 to 30%. Here, the translucent envelope coverage is defined as the area covered by the transparent conductive film and the cathode electrodes provided on both ends provided coaxially with the central axis of the translucent envelope. And the ratio of the surface area of the light-transmitting encapsulant to the surface area of the light-transmitting encapsulant on the same cross section perpendicular to the axial direction with respect to each tip of both electrodes of the anode electrode.

Preferably, glass is used as the material of the light-transmitting seal, but the material is not limited to glass. The material for forming the transparent conductive film is preferably a solution of an organometallic compound containing indium or tin as a main component metal, and the material is heat-treated to form an oxide of indium (In ₂ O). ₃ + SnO ₂ ) or a tin oxide (SnO ₂ + Sb ₂ O ₃ ) as a main component to form a transparent conductive film. The film mainly composed of indium oxide is called an ITO film. In the present invention, these materials are not particularly limited.

[0007] As a result, the amount of light is increased as compared with the conventional flash discharge tube, and the minimum emission voltage at which continuous light emission is possible under certain conditions is not increased. A flash discharge tube having excellent light emission reliability can be obtained. The details of the light emission reliability test method and the like will be described later.

Further, in the flash discharge tube according to the present invention,
The light-transmissive seal is provided at one end of the light-transmissive seal and coaxial with a central axis of the light-transmissive seal. It is preferable that the transparent encapsulant is covered with the transparent conductive film in a belt shape from the vicinity of the surface position to the center in the axial direction so that the translucent encapsulant coverage is 5% or more. That is, the above-described effect of the present invention can be obtained by forming a strip-shaped transparent conductive film corresponding to at least 5% of the covering ratio of the light-transmitting envelope near the tip of the cathode electrode.

Further, the method for manufacturing a flash discharge tube according to the present invention is a method for manufacturing a flash discharge tube in which a trigger electrode formed of a transparent conductive film is formed on the surface of a light-transmitting sealing material. Using a solution of an organometallic compound in which the main component metal is indium or tin, the surface of the light-transmitting encapsulant is coated by an immersion method, and after drying, the transparent conductive material is further coated on the transparent conductive material. Hot air is blown only to the portion where the conductive film is to be formed to oxidize indium or tin contained in the transparent conductive material and locally baked, and then the unfired portion of the transparent conductive material is etched with an acidic solution. It is characterized in that the strip-shaped transparent conductive film is formed on the surface of the light-transmitting encapsulation by removing. Here, the type of the hot air is not particularly limited as long as it is an oxygen-containing gas, but the use of air is simple and preferable.

Thus, a strip-shaped transparent conductive film is easily formed on the surface of the translucent sealing member, and the flash discharge tube according to the present invention can be suitably obtained. Further, in the above-described method, since the hot air is locally blown only to the portion to be fired in the coating layer of the transparent conductive material formed on the surface of the light-transmitting envelope, oxidation of the lead terminals of the flash discharge tube is prevented. This can prevent heat loss of the cesium component in the cathode electrode.

In the method for manufacturing a flash discharge tube according to the present invention, before forming a strip-shaped transparent conductive film on the surface of the light-transmitting envelope, an anode electrode or a cathode electrode is previously attached to both ends of the light-transmitting envelope. In the case where the transparent conductive film is provided by sealing treatment, after the transparent conductive film is formed, annealing may be further performed in a vacuum or under an inert gas atmosphere to further increase the conductivity of the transparent conductive film. It is possible and suitable.

On the other hand, in the case where a strip-shaped transparent conductive film is formed on the surface of the light-transmitting seal, and then the anode electrode or the cathode electrode is provided on both ends of the light-transmitting seal by sealing. Improving the conductivity of the transparent conductive film without specially performing the annealing process of the transparent conductive film because performing the sealing process simultaneously performs the annealing process of the transparent conductive film. The effect is obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a flash discharge tube and a method of manufacturing the same according to the present invention will be described below with reference to FIGS.

First, a configuration of a flash discharge tube according to an embodiment of the present invention and a method of manufacturing the same will be described with reference to FIGS.

As shown in FIG. 1, a flash discharge tube 10 according to the present embodiment is provided with a cathode electrode 14 and an anode electrode 16 provided at both ends of a glass tube 12 in a sealed manner. Lead terminals 18 are connected to the electrodes 16 respectively. Xenon gas 20 is sealed in the glass tube 12 at a predetermined pressure. The surface of the glass tube 12 is covered with a transparent conductive film 22 from the position of the surface of the glass tube 12 corresponding to the tip of the cathode electrode 14 to a predetermined surface position.

The transparent conductive film 22 is formed by the following method.

First, as shown in FIG.
A flash discharge tube 10 is prepared in which a cathode electrode 14 and an anode electrode 16 are provided at both ends by sealing.

Next, as shown in FIG. 2B, a bath 2 filled with a solution of an organometallic compound containing indium as a main component metal is used.
4 is immersed in the bath 24 with the cathode electrode 14 facing down to a position where the anode electrode 16 is not immersed, and the solution is coated by raising the flash discharge tube 10 at a pulling speed of about 10 mm / s. The covering film 22a is applied to the flash discharge tube 10. In a drying step not shown,
For example, after drying in a temperature atmosphere of about 60 ° C. for about 5 minutes, as shown by an arrow in FIG.
0 only locally from the upper end of the cathode electrode 14 to a predetermined height (W), for example, about 50 μm.
Air at a temperature of about 0 ° C. is sprayed at a rate of about ² l−air / cm ² −transparent conductive material / s (second) for about 20 s (second) to oxidize and burn indium in the solution.

Further, as shown in FIG. 2D, a bath 26 filled with a 1N hydrochloric acid aqueous solution is prepared, and the entire flash discharge tube 10 is immersed in the bath 26 for about 30 s (second). Thereby, the coating film 22a of the flash discharge tube 10 is formed.
Is removed by dissolving in a hydrochloric acid aqueous solution in the bath 26, and only the coating film 22b of the oxidized portion near the cathode electrode 14 previously heated by the high-temperature air remains. Thereafter, by performing washing and drying in a washing step (not shown), the formation of the strip-shaped transparent conductive film 22b having a predetermined width (W) on the surface of the flash discharge tube 10 is completed.

Preferably, as shown in FIG. 2E, the flash discharge tube 10 is subsequently heated in a vacuum or in an inert gas atmosphere at a temperature of about 200 ° C. for about 20 minutes to perform an annealing treatment. . Thereby, the conductivity of the transparent conductive film 22b can be improved.

The flash discharge tube 10 according to the present embodiment
When the operation of sealing the cathode electrode 14 and the anode electrode 16 at both ends of the glass tube 12 is performed in the final step after forming the transparent conductive film 22b instead of the manufacturing method described in Thereby, the transparent conductive film 22 can also serve as an annealing process.

Next, the flash discharge tube 10 according to the present embodiment
Regarding the evaluation method and the evaluation result of the light emission characteristics of
This will be described below with reference to FIG.

The evaluation of the light emission characteristics of the flash discharge tube 10 is shown in FIG.
The basic circuit shown in FIG. That is, the basic circuit includes a dry battery 28 as a power supply and a DC-DC converter 30 for increasing the voltage of the dry battery 28,
The main capacitor 32 is connected to the DC converter 30. The main capacitor 32 is further connected in parallel with a voltage dividing circuit including a resistor 34 and a resistor 36, and a pilot lamp 38 is connected between the voltage dividing point and a ground line.
To the main capacitor 32, a series circuit of a resistor 40, a trigger capacitor 42 and a resistor 44 is further connected in parallel, and a pair of electrodes of the flash discharge tube 10 is connected. One end of a primary winding 48 of a trigger coil 46 is connected to one end of the trigger capacitor 42, and the other end of the trigger capacitor 42 and the other end of the primary winding 48 are connected to a switch 50. The secondary winding 52 of the trigger coil 46 is connected to a trigger electrode 54 made of a transparent conductive film.

When a power switch (not shown) is turned on, the voltage of the main capacitor 32 is increased to several hundred volts, and the preparation for light emission is completed. Next, when the switch 50 is turned on,
A pulse of several kV is generated in the secondary winding 52 of the trigger coil 46 and is applied to the trigger electrode 54 to induce a discharge, so that the flash discharge tube 10 emits light. Light emission is continuously repeated by turning on and off the switch 50. Here, in order to measure the light emission amount, an integrating sphere 56 as a light receiving element is provided so as to be opposed to the flash discharge tube 10.

The evaluation of the light emission characteristics was performed for the following three items.

In the basic circuit of the flash discharge tube 10, the amount of light is measured by the main capacitor 32 having a capacitance of 100 μF.
Was charged at 280 V to emit light, the light amount was measured using the integrating sphere 56, and this was converted into a guide number (light amount). The average value of 10 flash discharge tubes 10 was used for the evaluation.

The minimum light emission voltage is such that the capacitance is 100 μm.
In the case where the main capacitor 32 of F was boosted in steps of 5 V starting from a voltage of 140 V, the lowest voltage was obtained when all the lights were emitted five times in succession. Also for this, the average value of the ten flash discharge tubes 10 was used for the evaluation.

The pass rate of the continuous light emission test is as follows. In the basic circuit of the flash discharge tube 10, the main capacitor 32 having a capacitance of 170 μF is charged at 320 V and emitted continuously 300 times at intervals of 20 seconds (seconds). A case where all 300 times of light emission were determined as a pass, and a ratio of the number of passed flash discharge tubes 10 performed at each set voltage.

The flash discharge tube 10 to be evaluated has a light-transmitting envelope coverage ((W / W ₀ ) × glass tube circumference × 100 in FIG. 1) of 100% and 54.0%. , 23.0
%, 15.4%, 7.7%, 3.8%, 0%.

FIGS. 4 to 6 show the evaluation results for each evaluation item.

The guide number (light quantity) shown in FIG. 4 increases remarkably as the translucent envelope coverage decreases, and is, for example, 50% as compared with the case where the translucent envelope coverage is 100%.
Is similar to the above-mentioned knowledge, but the light-transmitting envelope coverage is less than 5% in the range where the light-transmitting envelope coverage is smaller this time. Until then, it was found that the increasing trend continued.

The minimum emission voltage shown in FIG. 5 is maintained at substantially the same level even when the light-transmitting envelope coverage is reduced to 5%. It turned out to rise sharply.

The pass rate of the continuous light emission test shown in FIG. 6 is maintained at 100% even when the translucent envelope coverage is reduced to 5%. It was found that when the amount was reduced, it decreased sharply.

Comprehensively judging the above evaluation results, in order to secure a sufficient amount of light and obtain a flash discharge tube with high light emission reliability, the covering ratio of the transparent conductive film with the transparent conductive film should be 5%. It has been found that it is preferable to be within the range of ３０30%.

[0035]

As described above, according to the flash discharge tube according to the present invention, in the flash discharge tube in which the trigger electrode made of the transparent conductive film is formed on the surface of the translucent envelope, the transparent conductive tube is formed. The covering ratio of the light-transmitting sealing material with the conductive film is in the range of 5 to 30%.

Therefore, a sufficient amount of light can be obtained, and an effect that a flash discharge tube excellent in light emission reliability can be obtained can be achieved.

Further, according to the method for manufacturing a flash discharge tube according to the present invention, the surface of the light-transmissive envelope is immersed by using a solution of an organic metal compound such as indium as a main component metal as a transparent conductive material. After drying, the hot air is blown only to a portion of the coating layer of the transparent conductive material where a transparent conductive film is to be formed to oxidize indium and the like contained in the transparent conductive material. The transparent conductive material is locally fired, and then the unfired portion of the transparent conductive material is removed by etching with an acidic solution to form a strip-shaped transparent conductive film on the surface of the light-transmitting sealing body.

Therefore, a strip-shaped transparent conductive film can be easily formed on the surface of the light-transmitting seal, and the effect that the flash discharge tube according to the present invention can be suitably obtained is achieved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a flash discharge tube according to the present embodiment.

2 is a schematic process diagram for explaining a process of forming a transparent conductive film on the surface of a glass tube in the flash discharge tube of FIG. 1, and FIG. 2A shows a cathode electrode and an anode on both ends of the glass tube; FIG. 2B is a schematic external view of a flash discharge tube provided with electrodes in a sealing process, and FIG. 2B is an explanatory diagram showing a step of dipping and applying the flash discharge tube of FIG. 2A in a solution of a transparent conductive material. FIG. 2C is an explanatory view showing a step of blowing high-temperature air onto a portion of the flash tube of FIG. 2B where a transparent conductive film is to be formed, and FIG. 2D is a step of etching the flash tube of FIG. 2C with an acidic solution. The left part is an explanatory diagram showing a state before processing, the right part is an explanatory diagram showing a state after processing,
FIG. 2E is an explanatory view showing a step of performing an annealing process on the transparent conductive film of the flash discharge tube of FIG. 2D.

FIG. 3 is a basic circuit diagram used to evaluate the light emission characteristics of the flash discharge tube according to the present embodiment.

FIG. 4 is a graph showing the relationship between the light quantity of the flash discharge tube according to the present embodiment and the translucent envelope coverage.

FIG. 5 is a graph showing the relationship between the minimum emission voltage of the flash discharge tube according to the present embodiment and the light-transmitting envelope coverage.

FIG. 6 is a graph showing a relationship between a pass rate of a continuous light emission test of the flash discharge tube according to the present embodiment and a translucent envelope coverage.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Flash discharge tube 12 ... Glass tube 14 ... Cathode electrode 16 ... Anode electrode 22 ... Transparent conductive film 22a, 22b ...
Coating film 24, 26 bath 32 main capacitor 54 trigger electrode 56 integrating sphere

Claims (3)

[Claims] 1. A flash discharge tube in which a trigger electrode made of a transparent conductive film is formed on the surface of a light-transmitting envelope, wherein the light-transmitting envelope is covered by the transparent conductive film in a range of 5 to 30%. A flash discharge tube characterized by being inside. 2. A flash discharge tube according to claim 1, wherein said light-transmitting sealing member is provided at one end of said light-transmitting sealing member with a cathode electrode provided coaxially with a central axis of said light-transmitting sealing member. The translucent envelope coverage is 5% from near the surface position of the translucent envelope to the center in the axial direction on the same cross section perpendicular to the tip and the axial direction.
A flash discharge tube which is covered with a transparent conductive film in a strip shape as described above. 3. A method for manufacturing a flash discharge tube in which a trigger electrode made of a transparent conductive film is formed on a surface of a light-transmitting seal, wherein an organic metal compound whose main component metal is indium or tin as a transparent conductive material. The surface of the light-transmissive envelope is coated by a dipping method using the above solution and dried, and then hot air is blown only to a portion of the coating layer of the transparent conductive material where a transparent conductive film is to be formed. The indium or tin contained in the transparent conductive material is oxidized and locally baked, and then the unfired portion of the transparent conductive material is removed by etching with an acidic solution to form a surface of the light-transmissive envelope. A method for manufacturing a flash discharge tube, comprising forming the strip-shaped transparent conductive film.