JPH10294083A - Duplex tube type fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the rise of temperature of a glass bulb excellent by making the wall thickness of the glass bulb thin, and concurrently, easily collect emitted visible light to the direction required. SOLUTION: In a duplex tube type fluorescent lamp where let a fluorescent lamp represents an inner tube 1, and the fluorescent lamp comprises the inner tube 1 enclosed inside an outer tube 6 make of glass by way of a clearance, glass bulbs 2 and 7 consisting of the inner and outer bulbs 1 and 6, are as thin as 0.1 to 0.25 mm except sealing parts at both its ends, and a reflection film 8 is formed over the inner or outer surface of the outer tube 6 for the place corresponding to the light emitting part of the inner tube 1 in a range of 90 deg. to 320 deg. in the circumferential direction around the center of the longitudinal cross section of the inner tube 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double tube fluorescent lamp used as a display light source for a liquid crystal display, an instrument display panel, and the like.

[0002]

2. Description of the Related Art Fluorescent lamps used as back light sources for liquid crystal display panels and the like have been developed with further miniaturization, power saving, and high performance. As described above, it is demanded from the market that the fluorescent lamp can be used in any environment as an important function. In order to meet this demand, a double-tube fluorescent lamp has been developed in which a fluorescent lamp is sealed in an outer tube in which a rare gas of a vacuum or less than 1 atm is sealed.

FIG. 10 shows an example of a conventional double tube fluorescent lamp.
This will be described with reference to FIG. First, in FIG. 10, an inner tube 1 is formed by forming a phosphor film 3 on the inner surface of a glass bulb 2 to form a light emitting portion, and sealing an inner electrode 4 electrically connected to a lead wire 5 on both inner sides. Is hermetically sealed in the outer tube 6 via a gap, and the inside of the outer tube 6 is evacuated, or a rare gas is sealed in a state of less than 1 atm. The inner pipe 1 and the outer pipe 6 have a wall thickness of 0.30 other than the sealing portions at both ends.
It is formed to 0.40 mm.

[0004] In FIG. 11, as in FIG.
The outer tube 6 has a thickness of 0.30 to 0.40 mm other than the sealing portion.
The sealing portion of the inner tube 1 is positioned more inward than the sealing portion of the outer tube 6 with a gap therebetween, and the introduction line 5 is connected to the sealing portions of both the inner tube 1 and the outer tube 6. It is configured to be able to supply power from an external power supply by penetrating airtightly.

[0005]

However, in the prior art, since the outer tube is made of transparent glass, visible light is uniformly emitted from the outer peripheral surface of the inner tube. In the case where the light guide plate is incorporated, it is necessary to provide a reflector material for condensing visible light on the incident angle side of the light guide plate.

Further, since the thickness of the glass bulbs constituting the inner tube and the outer tube other than the sealing portions at both ends is as thick as 0.30 to 0.40 mm, the heat generated in the discharge space of the inner tube is reduced. There is a problem in that the heat is easily transmitted to the glass bulb wall portion of the inner tube, the temperature of the glass bulb and the mercury vapor pressure are hardly increased, and as a result, power saving cannot be achieved.

Accordingly, the present invention is to provide a structure in which the thickness of the glass bulb itself is reduced to improve the temperature rise of the glass bulb, and that the emitted visible light can be easily focused in a required direction. Accordingly, it is an object of the present invention to save power and make the liquid crystal display device smaller and thinner.

[0008]

In order to achieve the above object, according to the present invention, there is provided a fluorescent lamp having a fluorescent film formed on the inner surface of a glass bulb so as to emit light when energized. An inner tube, the inner tube being hermetically sealed in a glass outer tube through a gap, and the inside of the glass outer tube being evacuated or filled with a rare gas at less than 1 atm. In the tube-type fluorescent lamp, the thickness of the glass bulb constituting the inner tube and the outer tube other than the sealing portions at both ends,
0.1 to 0.25 mm.

According to the second aspect of the present invention, a light reflecting film is formed on the inner surface of the outer tube. The light reflection film is formed at a position corresponding to the light emitting portion of the inner tube and in a range of 90 to 320 ° in the circumferential direction around the center of the longitudinal section of the inner tube.

According to a third aspect of the present invention, a light reflecting film is provided on the outer surface of the outer tube, and at a position corresponding to the light emitting portion of the inner tube,
And a circumferential direction 90-320 around the center of the longitudinal section of the inner pipe.
It is characterized in that it is formed in the range of ゜.

[0011]

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

FIG. 1 is a cutaway longitudinal sectional view of a double tube fluorescent lamp. In this figure, an inner tube 1 is a straight glass tube 2 made of hard glass, a phosphor film 3 is formed on the inner surface, a rare gas or a small amount of mercury is sealed inside, and both ends are sealed. I have. The thickness of the glass bulb 2 other than the sealing portion is set to 0.
It is formed as a thin wall of 1 to 0.25 mm. A pair of internal electrodes 4, 4 are opposed to each other and sealed inside the glass bulb 2. The introduction lines 5, 5 are electrically connected to the internal electrodes 4, 4, respectively.

The outer tube 6 is a straight glass tube 7 made of hard glass. The inside is evacuated or sealed with a rare gas of less than 1 atm, and the inner surface of the glass valve 7 and the outer surface of the glass bulb 2 are connected. Between 0.1 and 0.
The inner tube 1 is hermetically sealed with a gap of 2 mm. The sealed portions at both ends of the inner tube 1 and the outer tube 6 are formed at the same position, and the introduction wire 5 is led out airtight to the outside by the sealed portions at both ends. The thickness of the glass bulb 7 other than the sealing portion is
It is formed as a thin wall of 0.1 to 0.25 mm.

In the present embodiment, when power is supplied from an external power supply through the introduction line 5, secondary electrons are emitted by ions in the initial plasma and are discharged in the inner tube 1,
Emits ultraviolet light. This ultraviolet light is converted into visible light by the phosphor coating 3 formed on the inner surface of the inner tube 1.
The visible light emitted to the outside of the inner tube 1 is emitted to the outside of the double tube fluorescent lamp via the outer tube 1 and consequently emits light.

The embodiment shown in FIG. 2 will be described. For the sake of simplicity, parts having the same functions as those in FIG. 1 will be described using the same reference numerals. The sealing portion of the outer tube 6 is the inner tube 1
Is provided so as to be located outward with a gap between the sealing portion. The lead-in wire 5 airtightly led out from the attachment portion of the inner tube 1 passes through a gap formed between the inner tube 1 and the outer tube 6, and passes through the attachment portion of the outer tube 6 in an airtight manner. It is derived outside. Other configurations are completely the same as those of the embodiment shown in FIG.

The relationship between the lamp power and the total luminous efficiency of the double-tube fluorescent lamp in the embodiment shown in FIGS. 1 and 2 will be described according to the thickness of the glass bulb of the outer bulb and the inner bulb. It measured according to thickness. The result is as shown in FIG. Both glass bulbs are formed with the same thickness,
In the graph of FIG. 3, the thickness of 0.1 mm is indicated by a solid line A, that of 0.25 mm is indicated by a dashed line B, and that of 0.3 mm is indicated by a dotted line C, 0.4 m
m is indicated by a two-dot chain line D. From the graph, when the thickness of the glass bulb that constitutes the tube is reduced,
It was found that the relative luminous efficiency of the lamp was improved.

In the embodiment shown in FIGS. 4 and 5,
A phosphor coating 3 is formed on the inner surface of a glass bulb 2 having a thickness of 0.1 to 0.25 mm other than the sealing portion, and a rare gas or a small amount of mercury is sealed therein, and the inside of both ends is sealed. The inner tube 1 to which the internal electrodes 4 and 4 are sealed is hermetically sealed in a straight tube type glass bulb 7 having a thickness of 0.1 to 0.25 mm other than the sealing portion. The sealed portions at both ends of the inner tube 1 and the outer tube 6 are formed at the same position. A vacuum or a rare gas of less than 1 atm is sealed in a gap of 0.1 to 0.2 mm as a vertical line distance formed between the inner surface of the inner tube 1 and the inner surface of the outer tube 6. It is formed in a structure that does not easily conduct heat.
A reflection film 8 made of aluminum is formed on the inner surface of the glass bulb 7 constituting the outer tube 6 within a range of 90 to 320 ° in the circumferential direction around the axis of the inner tube 1. Regarding the range in which the aluminum reflective film 8 is formed, the angle of light condensing can be adjusted by freely changing the angle in the range of 90 to 320 ° according to the required display area of the display device in which the double tube fluorescent lamp is incorporated. I just need. The reflection film 8 is not limited to the one made of aluminum, but may be any one having high visible light reflection characteristics. For example, a highly reflective white ink or a highly reflective Ag paste ink may be applied.

In the present embodiment, there is an effect that the visible light emitted from the inner tube 1 is directed in a specific direction.

In the embodiment shown in FIGS. 6 and 7,
As in the embodiment shown in FIG.
Phosphor coating 3 on the inner surface of glass bulb 2
The inner tube 1 formed by sealing the inner electrode 4 at both ends and enclosing a rare gas or a small amount of mercury is placed at a vertical distance from the outer surface of the inner tube 1 of 0.1 to 0.1 mm. The straight tube-shaped glass bulb 7 is hermetically sealed with a gap of 2 mm. A gap is formed between the sealed portions at both ends of the inner tube 1 and the outer tube 6. Introductory line 5 electrically connected to internal electrode 4
Are hermetically guided to the gap from both end sealing portions of the inner tube 1, pass through this gap, and are hermetically led to the outside from the both end sealing portions of the outer tube 6. As in the embodiments shown in FIGS. 1, 2 and 4, the outer tube 6 is filled with a rare gas of less than 1 atm or is formed in a vacuum. An aluminum reflective film 8 is formed on the outer surface of the glass bulb 7 within a range of 90 to 320 ° in the circumferential direction around the axis of the inner tube 1. The reflection film 8 is not limited to the one made of aluminum, but any material having high visible light reflection characteristics is sufficient. For example, a highly reflective white ink or a highly reflective Ag paste ink may be applied, or an A1 vapor-deposited, Ag-deposited film, or white reflective film may be used.

As shown in FIG. 8, when a double-tube fluorescent lamp having a reflective film 8 is attached to a backlight device, the lamp holder is arranged such that the non-reflective film-formed portion faces the light guide plate 9. Attach to 10. 11 is a reflection sheet, 12
Is a diffusion sheet.

In the graph of FIG. 9, the solid line E indicates the light emission light intensity of the double tube fluorescent lamp having a reflective film, and the dotted line F indicates the light emission light intensity of the double tube fluorescent lamp having no reflective film. I have. The inner diameter of the inner tube 1 was 1.6 mm, the gap between the inner tube and the outer tube was 0.2 mm in vertical line distance, the thickness of the inner and outer tube glass bulbs was 0.2 mm, and formed on the outer surface of the outer tube. The reflection film formed in a range of 270 ° in the circumferential direction around the axis was measured as a sample. From the solid line E in the graph of FIG. 9, it can be seen that the light emission light intensity in the specific direction is 1.7 times or more as compared with the case where the reflection film is not formed.

In the embodiment described above, the glass bulb has a straight tube type as an example. However, the present invention is not limited to this, and L-shaped, U-shaped, U-shaped, etc. In addition, the vertical cross-sectional shape of the glass bulb is not limited to a circular shape, but includes a rectangular flat fluorescent tube and the like.

[0023]

According to the present invention, when the thickness of the glass bulb is specified to be extremely thin, the temperature of the inner tube is easily increased, and the vapor pressure of mercury is also easily increased. Since the outer diameter of the bulb can be reduced, a high-performance compact lamp can be provided.

Since the double-tube fluorescent lamp is provided with a reflection film for condensing light in a specific direction, there is no need to separately provide a reflection member in the lamp unit, so that the liquid crystal display device can be made more compact and compact. There is an effect that it can be achieved.

[Brief description of the drawings]

FIG. 1 is a cutaway sectional view of a double tube fluorescent lamp.

FIG. 2 is a cutaway sectional view of a double-tube fluorescent lamp according to another embodiment.

FIG. 3 is a graph showing the relationship between lamp power and total luminous efficiency.

FIG. 4 is a cutaway sectional view of a double-tube fluorescent lamp according to another embodiment.

FIG. 5 is a longitudinal sectional view of FIG.

FIG. 6 is a cutaway sectional view of a double tube fluorescent lamp according to another embodiment.

FIG. 7 is a longitudinal sectional view of FIG.

FIG. 8 is an explanatory diagram showing a state in which a double tube fluorescent lamp is incorporated in a backlight unit.

FIG. 9 is a graph showing light emission light intensity.

FIG. 10 is a cutaway sectional view of a conventional double tube fluorescent lamp.

FIG. 11 is a cutaway sectional view of a conventional double tube fluorescent lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner tube 2, 7 Glass bulb 3 Phosphor coating 6 Outer tube 8 Reflective film

Claims (3)

[Claims] 1. A fluorescent lamp having a fluorescent film 3 formed on an inner surface of a glass bulb 2 so as to emit light when energized is formed as an inner tube 1, and the inner tube 1 is connected to a glass outer tube 6 through a gap.
The inner tube 1 and the outer tube 6 are sealed in an airtight manner, and the inside of the glass outer tube 6 is evacuated, or a rare gas is sealed at less than 1 atm. The thickness of the constituent glass bulbs 2 and 7 other than the sealing portions at both ends is
A double-tube fluorescent lamp having a diameter of 0.1 to 0.25 mm. 2. A reflection film 8 is formed on the inner surface of the outer tube 6 at a position corresponding to the light emitting portion of the inner tube 1 and within a range of 90 to 320 ° in the circumferential direction around the center of the longitudinal section of the inner tube 1. The double-tube fluorescent lamp according to claim 1, wherein the fluorescent lamp is formed. 3. A reflective film 8 is provided on the outer surface of the outer tube 6 at a position corresponding to the light emitting portion of the inner tube 1 and within a range of 90 to 320 ° in a circumferential direction around the center of the longitudinal section of the inner tube 1. The double-tube fluorescent lamp according to claim 1, wherein the fluorescent lamp is formed.