JPH0713160Y2 - Fluorescent display tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a cathode, a control electrode, an anode, and lead pins connected to these electrodes inside an envelope whose interior is maintained in a high vacuum atmosphere. In particular, the present invention relates to a fluorescent display tube in which an extension lead is provided at the tip of a lead pin to facilitate mounting without a display wiring board.

[Prior art]

In a conventional fluorescent display tube, a flat box-shaped vacuum envelope is formed from a substrate, a side plate and a plane plate. An anode conductor is arranged on the substrate, and a phosphor layer is deposited on the anode conductor to form an anode. A control electrode made of a metal mesh was arranged above the anode, and a linear cathode was arranged above the control electrode. Electrodes such as a cathode, a control electrode, and an anode arranged on the substrate are covered with a container portion composed of a side plate and a plane plate, and sealed with the substrate to form a vacuum envelope. The electrodes and the like were connected to lead pins extending from the sealing portion in a state where the inside of the envelope was sealed, and were connected to an external drive circuit. This lead pin needs conductivity to apply a drive voltage to each electrode, and the lead pins do not contact each other. Conventionally, as shown in FIG. 4, the lead pin 21 of the fluorescent display tube 20 is for displaying. The fluorescent display tube 23 was fixed to the display substrate 22 by inserting into the through hole of the substrate 22 and soldering. Then, the display substrate 22 and the printed circuit board 23 on which the drive circuit is arranged are connected by the flexible cable 24. Therefore, the lead pin 27
Needed mechanical strength. Therefore, the lead pin 27
Needed some width and thickness.

Further, since the lead pin 27 is provided so as to penetrate the sealing portion between the glass substrate and the side plate, it is necessary to have a coefficient of thermal expansion substantially equal to that of glass. Therefore, conventionally, the lead pin has been formed of 426 alloy (42% Ni, 6% Cr, balance Fe alloy).

Recently, fluorescent display tubes have come to be used not only in electronic devices such as audio and video, but also in display devices of vehicle instrument panels. These fluorescent display tubes tend to have a large amount of display information and a large number of lead pins. And it is required to be compactly mounted on a display device. Therefore, the applicant did not fix the fluorescent display tube with the lead pin, but directly fixed the envelope to the front panel of the display device, connected the flexible cable to the lead pin, and attached the tip to the printed circuit board provided with the drive circuit. The idea that the display wiring board can be omitted by connecting it directly
I am applying for No. 18.

[Problems to be solved by the device]

When a conventional fluorescent display tube with a flexible cable is used in an instrument panel of a car, it has the following problems.

I. When the car is parked outdoors such as in winter, the temperature near the meter also drops to below 0 degrees, but when the engine is started, the temperature is near the meter because the engine is close to it.
Raises above 50 ℃. Therefore, the fluorescent display tube is also + 85 ℃
Guaranteed to operate normally up to -40 ° C. However, when there is such a temperature difference, dew condensation occurs on the metal part. Even in the conventional fluorescent display tube, since the metal lead pin is exposed near the envelope, dew condensation occurs on that portion, so that it is necessary to widen the lead pitch. However, if the number of pins is increased and the lead pitch interval cannot be widened, there is a problem in that adjacent lead pins conduct with each other using condensed water as a medium and a normal display operation cannot be performed.

B. In the fluorescent display tube, the amount of information to be displayed differs depending on the display device, and the number of lead pins or the arrangement position also changes accordingly. Therefore, if the conventional cable is flexibly connected to the lead pin, a flexible cable must be newly prepared for each tube type, which also causes a cost increase.

Therefore, an object of the present invention is to provide a fluorescent display tube which operates normally even if dew condensation occurs and has the same operation and effect without using a flexible cable.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the fluorescent display tube of the present invention has a structure in which electrodes such as a cathode, a control electrode, and an anode arranged in an envelope are provided with a rigid lead pin. In the fluorescent display tube extended in the vicinity of the envelope, an extension lead made of a flexible metal thin wire is connected and fixed to the extension portion of the lead pin,
It is characterized in that the lead pin and the entire extension lead located outside the envelope are covered with a flexible sheet-like insulating material by bonding them from the front and back.

[Action]

According to the present invention, the exposed portions of the lead pins and extension leads of the fluorescent display tube are all covered with an insulating material, so even if dew condensation occurs, the lead pins do not come into direct contact with each other. Even under normal conditions, the fluorescent display tube operates normally.

[Embodiment 1] The present invention will be described below with reference to a first embodiment shown in the drawings.
FIG. 1 is a partially cutaway front view of the present invention, and FIG. 2 is a sectional view.

Reference numeral 1 is a vacuum envelope for a fluorescent display tube. As shown in FIG. 2, a glass plate forms a substrate 1a, a side plate 1b, and a flat plate 1c, which are assembled into a flat box shape by a glass solder. There is. The wiring pattern 2 and the anode conductor 3 are formed on the substrate 1a by a metal thin film, for example, an aluminum thin film. The phosphor layer 4 is adhered to the surface of the anode conductor 3 to form the anode 5. A control electrode 6 made of a metal mesh is disposed above the anode 5 and a linear cathode 7 is stretched above the control electrode 6. The anode 5 and the control electrode 6 are electrically connected by the wiring conductor 2 to the terminal portion 2a at the end of the substrate 1a. The linear cathode 7 is held by a cathode support 8,
A part of this cathode support becomes the lead pin 9a, and the envelope 1
Extends to the outside. Further, the anode 5 and the control electrode 6 extend from the terminal portion 2a to the outside of the envelope 1 by the lead pin 9b. The lead pins 9a, 9b are sealed and fixed by a glass sealing material between the substrate 1a and the side plate 1b.
Therefore, the material of the lead pins 9a and 9b is the glass substrate 1a.
It is preferable to use a conductive material having a coefficient of thermal expansion substantially equal to that of 426 alloy in this embodiment. The lead pins 9a, 9
The shape of the inside of the envelope 1 of b is formed in the shape of a spring, and it is brought into contact with the terminal portion 2a by being pressed to obtain conduction. Further, the extended portions of the lead pins 9a and 9b outside the envelope 1 are cut short in the vicinity of the envelope to have rigidity. A flexible metal wire is fixed to the extending portion by soldering or welding to form an extension lead 9c. Then, the lead pins 9a and 9b and the extension lead 9c on the outside of the envelope 1 are all covered from the front and back with a flexible insulating material and fixed with an adhesive so that the metal wires of the extension lead 9c do not come into contact with each other. I am configuring.

As an example of the insulating material, it is possible to use a flexible insulating sheet 10 which is made by forming a synthetic resin such as a polyamide resin, a polyester resin, a Teflon resin, or a polyimide resin into a sheet shape to give flexibility. An adhesive is applied to the insulating sheet 10, and the lead pins 9a and 9b and the extension lead 9c on the outside of the envelope are bonded to each other from the front and back sides so that the entire extension lead 9C is not exposed. The outer tip of the extension lead 9c may be exposed only when soldering to a printed circuit board provided with a drive circuit. In this embodiment, the insulating sheet 10 is covered with the integral insulating sheet 10 from the rigid lead pins 9a and 9b to the extension lead 9c. As described above, since the portions other than the flexible portion are adhered, peeling can be prevented.

〔effect〕

As described above, the present invention has the following effects because the outer portion of the envelope of the lead pin of the fluorescent display tube and the extension lead are covered with the insulating material.

I. Even if the fluorescent display tube is driven in an environment where condensation occurs, condensation does not directly adhere to the lead pins on the outside of the envelope, short circuit between lead pins can be prevented, and normal driving is always possible. .

B. Since the insulation layers on the front and back of the extension lead are formed,
It is possible to prevent a short circuit between the metal wires of the extension lead and a contact between the extension lead and other parts.

C. Since the extension lead has flexibility, soldering with the printed circuit board becomes easy.

D. In the case of the extension lead joined on the outside of the envelope, the joining force is further enhanced by coating the insulating layer.

[Brief description of drawings]

FIG. 1 is a plan view in which a part of the fluorescent display tube of the present invention is cut away, FIG. 2 is an enlarged cross-sectional view of an essential part of the present invention, and FIG.
It is explanatory drawing which shows the conventional mounting method. 1 ... Enclosure, 3 ... Anode conductor 4 ... Phosphor layer, 5 ... Anode 6 ... Control electrode, 7 ... Cathode 9a, 9b ... Lead pin 9c ... Extension lead 10 ... Insulating material ( Insulating sheet)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Shown 52-57563 (JP, U) Shown 59-194255 (JP, U) Shown 62-43450 (JP, U)

Claims (2)

[Scope of utility model registration request] 1. A fluorescent display tube in which electrodes such as a cathode, a control electrode, and an anode arranged in an envelope are extended in the vicinity of the envelope by a lead pin having rigidity, and at an extension portion of the lead pin. An extension lead made of a thin metal wire having flexibility is bonded and fixed, and the lead pin located outside the envelope and the entire extension lead are covered with a sheet-like insulating material having flexibility and covered from the front and back sides. Characteristic fluorescent display tube. 2. The fluorescent display tube according to claim 1, wherein a lead pin having a coefficient of thermal expansion of a metal close to glass and having rigidity, and an extension cord having flexibility are integrally formed at a tip thereof.