JPH079331Y2 - Voltage display discharge tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention discharges and emits light when a voltage applied to a circuit gradually increases and becomes a predetermined voltage or more.
The present invention relates to a voltage display discharge tube that informs that a voltage higher than a predetermined voltage is applied to a circuit. In particular, in the present invention, the discharge start voltage has a small error with respect to a set value, and a discharge delay occurs. The present invention relates to a voltage display discharge tube which is particularly useful as a charge completion lamp of a strobe device of a camera, etc.

[Prior Art] Conventionally, a voltage display discharge tube of this type has a structure in which a pair of discharge electrodes are opposed to each other across a discharge gap and are housed in an airtight container made of glass in which a discharge gas such as neon is sealed. There is something more. Since this voltage display discharge tube is small, it is built into the flash device of the camera, etc., and discharges and emits light when the voltage of the charging circuit etc. reaches a predetermined voltage, so that the user can complete the charging. To inform.

Here, the discharge start voltage of the voltage display discharge tube is mainly determined by the composition of the discharge gas, the gas pressure and the discharge gap, but the value of this voltage is accurate with a small error from the design value. Is required.

[Problems to be Solved by the Invention] However, in the conventional voltage display discharge tube described above, it is relatively easy to maintain the composition and gas pressure of the discharge gas substantially constant, but the size of the discharge gap is small. It is technically extremely difficult to set the value of the discharge starting voltage to an accurate value with a small error from the design value because it easily varies.

Further, even when the voltage applied to the voltage display discharge tube reached the discharge start voltage, the discharge did not occur immediately due to the discharge delay phenomenon, and the time of the discharge delay also contributed to the error. .

Therefore, the present invention solves the above-mentioned problems and makes the value of the discharge start voltage small with respect to the design value, and the discharge delay is minimized to perform accurate voltage display. It is an object of the present invention to provide a voltage display discharge tube that can be used.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the voltage-display discharge tube of the present invention is a light-tight and airtight seal in which discharge electrodes are opposed to each other with a discharge gap. In a voltage display discharge tube housed in a container, a mixture of a conductive substance and an insulating substance and a minute space in which a creeping discharge can be generated between the conductive substances is interposed between the discharge electrodes. It is a thing.

[Operation] The voltage display discharge tube of the present invention has a structure as described above, and a mixture in which a conductive material and an insulating material are mixed between discharge electrodes to form a minute space in which a creeping discharge can be generated between the conductive materials. With the interposition of, it becomes possible to maintain the discharge gap between the discharge electrodes substantially constant, and thereby the value of the discharge start voltage can be made accurate with less error with respect to the design value.

Furthermore, when the value of the voltage applied to the voltage display discharge tube reaches the discharge start voltage, a potential difference is generated between the conductive materials via the minute space, and electrons are immediately emitted from the conductive material.
A creeping discharge is generated on the surface of the insulating material between the conductive materials.
The creeping discharge generates electrons with the discharge, and is transferred between the discharge electrodes due to the priming effect of the electrons. In this case, the creeping discharge between the discharge electrodes is first formed between the discharge electrode and the conductive material in the vicinity of this electrode, which further extends like a stepping stone by using the conductive material in the vicinity as a foothold, A discharge path is formed between the discharge electrodes. This creeping discharge increases the voltage drop between the discharge electrodes as it expands, and finally shifts to a gas phase discharge between the discharge electrodes to generate a glow discharge in the discharge gap. Then, the light emitted from the glow discharge is emitted through the light-tight airtight container, thereby notifying the user that the voltage applied to the voltage display discharge tube has reached a predetermined voltage.

The creeping discharge that occurs between the solid phase and the vapor phase is a discharge phenomenon with a very small discharge time delay compared to the vapor phase discharge, and in the present invention, there are many small spaces where the creeping discharge occurs. In addition, since the creeping discharge jumps between the discharge electrodes and expands like stones, the discharge path between the discharge electrodes is formed in a short time. Therefore, the time from when the value of the applied voltage reaches the discharge start voltage to when the gas-phase discharge is formed between the discharge electrodes becomes extremely short, and the response characteristic is improved.

In addition, since the number of minute spaces (three-dimensionally existing instead of two-dimensionally) between the conductive materials is enormous, electrons are emitted everywhere in the conductive material and a creeping discharge occurs in the minute space. It is easy to do.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a voltage display discharge tube according to an embodiment of the present invention, and FIG. 2 is a structural explanatory view of a mixture used in the present invention. In the figure, the voltage display discharge tube 1 is made of a material having good discharge characteristics, such as nickel, iron, or an alloy thereof, at both ends of a mixture 2 of a conductive material 2a and an insulating material 2b, and has a bottomed cylindrical shape. The discharge electrodes 3, 3'are connected by connecting the respective bottoms of a pair of discharge electrodes 3, 3'having a form in which the opening diameter gradually increases from the middle portion toward the opening edge.
A discharge gap 4 is formed between the opposing opening edges of the two, and the discharge gap 4 is formed by sealing sealing caps 5b, 5b 'made of Dumet wire to both ends of an outer enclosure 5a made of a translucent glass tube. It is housed in the airtight container 5 and has a structure in which the discharge electrodes 3 and 3'and the sealing caps 5b and 5b 'are connected to each other.
Further, the airtight container 5 is filled with a discharge gas composed of an inert gas mainly containing a rare gas such as neon, argon or xenon.

The mixture 2 is composed of a conductive material 2a made of powdered metal such as nickel, zinc or molybdenum, and a porous material such as activated alumina, zeolite or clay, or a powdered insulating material 2b made of glass. It is mixed in a ratio and baked into a desired shape to form a rod. The conductive material 2a becomes a good conductor if the mixture is fired in a deoxidizing atmosphere, and becomes a semiconductor by forming a thin oxide film on the surface of the metal if firing the mixture in an oxidizing atmosphere. In the case of a semiconductor, depending on the material, electrons tend to be easily emitted when a voltage is applied. When the conductive material 2a is composed of a semiconductor, a semiconductor material mainly composed of a metal oxide such as nickel oxide, zinc oxide or molybdenum, or a semiconductor material other than a metal oxide such as silicon carbide is used from the beginning. It goes without saying that you can do it.

The fine structure inside the mixture 2 is as shown in FIG. 2, in which the granular insulating material 2b is dispersed substantially uniformly between the granular conductive material 2a to form a minute space 2c between the conductive materials 2a. Is
The conductive materials 2a are prevented from being connected to each other for a long time.

The manufacturing process of the voltage display discharge tube 1 of this embodiment will be described in detail below.

First, the bottoms of the discharge electrodes 3 and 3'are connected to both ends of the mixture 2 of the conductive substance 2a and the insulating substance 2b, and the discharge gap 4 is formed between the opposite opening edges of the discharge electrodes 3 and 3 '. To form. Next, a substantially cylindrical sealing cap 5b made of Dumet wire is fitted into one end of the outer envelope body 5a made of a glass tube. Then, the mixture 2 in which the electrodes 3 and 3'are connected to each other is used as the envelope 5a.
Then, the sealing cap 5b 'is fitted into the opening end of the outer casing 5a. After assembling in this way, the inside of the envelope 5a is evacuated in the tank, and a discharge gas consisting of an inert gas mainly containing a rare gas such as neon, argon, or xenon is introduced into the envelope 5a. Encapsulate. Further, this is heated to seal the outer enclosure 5a and the sealing caps 5b and 5b ′,
The airtight container 5 is formed. Due to this heating action, the envelope 5a made of a glass tube contracts, whereby the discharge electrodes 3, 3 '.
The sealing caps 5b and 5b 'are pressure-bonded to each other to ensure a reliable connection.

Incidentally, in the above-mentioned embodiment, the conductive material 2a and the insulating material
As a means for mixing with 2b, these are mixed to form the rod-shaped mixture 2, but the mixture is not limited to this example. For example, a mixture of a conductive substance and an insulating substance may be applied as a layer on the surface of the insulator using the insulator as a support, or only the conductive substance may be sprayed on the surface of the insulator so that the conductive substances are attached so thinly that they do not continue for a long time You may let me do it. Further, in this embodiment, the chip type voltage display discharge tube 1 having no external terminal has been described, but it is a voltage display discharge tube having external terminals provided at both ends of the sealing caps 5b and 5b '. Of course, it doesn't matter.

In the voltage display discharge tube 1 of the present embodiment, the discharge phenomenon is generated away from the mixture 2 by gradually increasing the opening diameter from the middle part of the discharge electrodes 3, 3'to the opening edge. Thus, the thermal effect of the discharge phenomenon generated in the discharge gap 4 on the mixture 2 is reduced. Therefore, the mixture 2 does not reach a high temperature state and hardly generates an impure gas generated when the substance is exposed to a high temperature. Therefore, even if discharge display is repeated, the composition of the discharge gas in the airtight container remains unchanged. This does not change so much, and thus accurate voltage display can always be performed stably.

[Effect of the Invention] As described in detail above, according to the voltage display discharge tube of the present invention,
By maintaining a discharge gap between discharge electrodes by interposing a mixture of a conductive substance and an insulating substance between the discharge electrodes and interposing a mixture forming a minute space where a creeping discharge can be generated between the conductive substances. It becomes possible to make the value of the discharge starting voltage accurate with less error with respect to the design value.

Further, when the value of the voltage applied to the voltage display discharge tube reaches the discharge start voltage, a potential difference is generated between the conductive materials through the minute space, and a creeping discharge is generated on the surface of the insulating material between the conductive materials. Since the discharge triggers the discharge phenomenon in the discharge gap, the state of the voltage display discharge tube is extremely short in discharge delay.

Therefore, in the present invention, the inaccuracy due to the large value of the discharge start voltage in the conventional voltage display discharge tube with respect to the design value and the inaccuracy due to the large discharge delay. Therefore, it is possible to provide an extremely accurate voltage display, and it is possible to provide a particularly useful voltage display discharge tube that is used as a charge completion lamp of a flash device of a camera.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a voltage display discharge tube of the present invention,
FIG. 2 is a structural explanatory view of the mixture used in the present invention. 1 ... Voltage display discharge tube, 2 ... Mixture, 2a ... Conductive material, 2b ... Insulating material, 3 ... Discharge electrode, 4 ... Discharge gap, 5 ... Airtight container

Claims (1)

[Scope of utility model registration request] 1. A voltage display discharge tube in which discharge electrodes facing each other across a discharge gap are housed in a translucent airtight container filled with a discharge gas. A voltage display discharge tube, characterized in that a mixture forming a minute space in which a creeping discharge can be generated between substances is interposed between the discharge electrodes.