JPH0636744A - Discharge tube - Google Patents

Abstract

PURPOSE:To improve intensity by using the luminescence on the surface side of a fluorescent screen as the discharge light. CONSTITUTION:An electrode 51 containing an electron emissive material and a conical electrode 52 arranged on the outer periphery of the electrode 51 are caulked and fixed at the tip section of an inner lead 4 held in a glass tube 1 through the end section of the glass tube 1 to constitute an electrode device 5. A glass tube 6 is provided in the glass tube 1, and a fluorescent screen 3 is provided on the outer periphery of the glass tube 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge tube applied to, for example, a backlight for a liquid crystal panel, and in particular, it is constituted by enclosing a rare gas and mercury in a glass tube and connected to inner leads at both ends. The present invention relates to a discharge tube formed by opposingly arranging an electrode device including a first electrode portion and a second electrode portion surrounding the outer periphery of the first electrode portion, and more specifically, to a structure of a phosphor screen thereof. Is.

[0002]

2. Description of the Related Art With recent advances in liquid crystal technology, liquid crystal display panels have come to be widely used in various display devices. Recently, a liquid crystal display device using this liquid crystal display panel has been strongly demanded to be particularly small and lightweight, and in order to satisfy the requirements relating to such a liquid crystal display device, a discharge tube is widely used as a backlight of the liquid crystal display panel. Has been adopted.
Therefore, in order to manufacture a miniaturized liquid crystal display device, it has been particularly required to improve the liquid crystal display panel and miniaturize the backlight. At the same time, in order to improve the display quality, higher brightness and longer life are required.

FIG. 3 is a diagram for explaining the structure of this type of discharge tube, FIG. 3 (a) is a sectional view, and FIG. 3 (b) is an enlarged perspective view of essential parts of the electrode device. In FIG. 3 (a), 1 is a transparent glass tube forming the main body of the discharge tube, 2 is an ultraviolet reflection film formed on the inner wall surface of the glass tube 1, and 3 is a phosphor coated on the ultraviolet reflection film 2. The formed fluorescent screen,
Reference numeral 4 denotes an inner lead held at the longitudinal end of the glass tube 1 so as to pass through the glass tube 1, and 5 is arranged coaxially in the longitudinal direction of the glass tube 1 so as to face the tip of each inner lead 4 and to face each other. And a pair of electrode devices. The glass tube 1 is filled with a mixed gas of, for example, argon gas and mercury for discharging.

Further, in FIG. 3 (b), 5 ₁ a first electrode that emits formed of a sintered metal body and thermal electrons including electron emitting substance at the tip of the inner lead 4, 5 ₂ the first This is a conical second electrode made of, for example, a nickel material molded body that is coaxially arranged by caulking and fixing so as to surround the _first electrode 5 ₁ .

In such a configuration, the pair of electrode devices 5 arranged to face each other is composed of the second electrode 5 ₂ surrounding the first electrode 5 ₁ , and these are arranged adjacent to each other. The electrode 5 _{1 of the above} is impregnated or coated on the surface with an emitter material as a thermoelectron emitting substance, and it functions as an arc discharge electrode, and the second electrode 5 ₂ functions as a glow discharge electrode. A stable discharge can be obtained. The thermionic emissive material or electrode member in which the ultra-high-intensity discharge is stably obtained and the first electrode 5 ₁ is sputtered and evaporated by the ion bombardment is the second electrode 5 ₂
Since it is trapped on the inner surface of the glass tube 1, the inner surface of the glass tube 1 is not blackened, and the trapped thermoelectron emitting material is used as the electron emitting material on the second electrode 5 _2. 5 discharge tube long life can be obtained by repeating the be reattached to the _first surface.

[0006]

However, in the discharge tube having such a structure, the light emission from the fluorescent screen 3 applied to the inner wall surface of the glass tube 1 is emitted from the rear side of the fluorescent screen 3. Since light is used as emitted light, there is a problem that sufficient brightness cannot be obtained. Further, the phosphor screen 3 has an unavoidable absorption of visible light by the phosphor itself, and thus has a problem that the amount of light emission per unit area is small and thus sufficient brightness cannot be obtained.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to improve the brightness by using the light emission on the front surface side of the phosphor screen as the emitted light. It is to provide a discharge tube that can.

[0008]

In order to achieve such an object, the present invention provides a glass tube in the discharge space and a fluorescent screen on the outer peripheral surface of the glass tube.

[0009]

In the present invention, by providing a fluorescent screen on the outer peripheral surface of the glass tube, the light emission on the surface side of the fluorescent screen can be emitted light.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of an embodiment of a discharge tube according to the present invention, and the same parts as those in the above-mentioned drawings are designated by the same reference numerals. In the figure, a first ultraviolet reflection film 2 made of, for example, titanium oxide is adhered to the inner peripheral wall surface of the translucent first glass tube 1. Further, in the discharge space inside the first glass tube 1, the second glass tube 6 having an outer diameter smaller than the inner diameter of the first glass tube 1 is provided on both ends of the inner lead of the electrode device 5. The structure is supported at the tip of the four glass tubes 4 and fixedly arranged substantially coaxially with the first glass tube 1.

Although not shown, the second glass tube 6 is provided with an opening and is set in the same gas atmosphere as the inside of the first glass tube 1. On the outer peripheral surface of the second glass tube 6, a second ultraviolet reflection film 7 made of, for example, titanium oxide is adhered and formed, and a phosphor is applied on the second ultraviolet reflection film 7. As a result, the fluorescent screen 3 is formed.

In such a structure, the first electrode 5 ₁
While preventing the electrode member and the electron emitting substance from scattering to the glass tube 1, thermionic emission by the electron emitting substance adhering to the inner surface of the second electrode 5 ₂ can be utilized, and the electron emitting substance is It is possible to achieve a longer life by reattaching the electrode 5 _{1 to} the surface of the electrode 5 ₁ .

According to this structure, the second glass tube 6 is provided in the discharge space, and the fluorescent surface 3 is provided on the outer peripheral surface of the second glass tube 6, whereby the surface side of the fluorescent surface 3 is provided. Is emitted to the inside of the first glass tube 1, diffusely reflected by the inner wall surface of the first glass tube 1, transmitted through the first glass tube 1 and output to the outside as emitted light. Become. Therefore, since only the light emission on the surface side of the phosphor screen 3 is used, there is no absorption of visible light by the phosphor itself, and the brightness can be improved.

FIG. 2 is a sectional view showing the structure of a discharge tube according to another embodiment of the present invention, and the same parts as those in the above-mentioned drawings are designated by the same reference numerals. In the figure, the difference from FIG. 1 is that the electrode devices 5 arranged at both ends of the first glass tube 1
The second glass tube 6 is integrally supported and fixedly disposed at both inner ends of the first glass tube 1 so as to penetrate therethrough. Even with such a configuration, the same effect as that of the above-described embodiment was obtained.

Further, the discharge tube thus constructed is
As a result of the inventors making a large amount of samples and performing the luminance measurement test a plurality of times, the luminance is significantly improved to about 20% as compared with the conventional structure without impairing other electrical characteristics. Was confirmed.

[0016] Incidentally, in the embodiment described above, the second electrode 5 ₂ has been described as being formed the overall shape substantially conical shape, the conical deformation body, such as a cylindrical or a variant thereof Of course, it may be formed in various shapes.

[0017]

As described above, according to the present invention,
Since the glass tube is provided in the discharge space and the fluorescent surface is provided on the outer peripheral surface of the glass tube, the light emission on the surface side of the fluorescent surface can be used as the emitted light, so that the brightness can be significantly improved. In addition, it has an extremely excellent effect such as obtaining a high-luminance discharge tube.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration according to an embodiment of a discharge tube according to the present invention.

FIG. 2 is a cross-sectional view showing a structure of a discharge tube according to another embodiment of the present invention.

FIG. 3A is a cross-sectional view showing the configuration of a conventional discharge tube,
FIG. 3B is an enlarged cross-sectional view of a main part showing the configuration of the electrode device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st glass tube 2 1st ultraviolet reflective film 3 fluorescent surface 4 inner lead 5 electrode device 5 ₁ 1st electrode 5 ₂ 2nd electrode 6 2nd glass tube 7 2nd ultraviolet reflective film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Kawai 700 Wada, Ueno Town, Ise City, Mie Prefecture, Ise Denshi Kogyo Co., Ltd. Company Noritake Company Limited (72) Inventor Yoshiyuki Okubo 3-1, 36 Noritake Shinmachi, Nishi-ku, Nagoya-shi Stock company Noritake Company Limited 3-72 (36) Inventor Sato Fuyu 3-36, Noritake Shincho, Nishi-ku, Nagoya Ceremony Company Noritake Company Limited

Claims (1)

[Claims] 1. A first electrode part connected to an inner lead, and a pair of electrode devices arranged opposite to each other in a discharge space in which at least a rare gas and mercury are sealed in a glass tube. A discharge tube comprising a second electrode portion surrounding an outer circumference, wherein a glass tube having an outer peripheral surface coated with a phosphor is arranged in the discharge space.