JPH02181354A - Flat fluorescent lamp - Google Patents

Abstract

PURPOSE:To reduce the shade of the luminance by making a reinforcing member so as that the axial cross section of which is narrower and narrower toward the front plate and the side surface of which is a curved surface. CONSTITUTION:A reinforcing spacer 21 is constructed so that the side surface of which is a recessed arc surface 21a toward the central axis. Hence light and UV generated in the vicinity of the said spacer 21 in the discharge space 9 are reflected irregularly on the arc surface 21a of the reinforcing spacer to be outputted toward the front plate 1a. As the reinforcing spacer 21 is made narrower and narrower toward the front plate 1a, the projected area of the spacer 21 on the front plate 1a can be reduced. For this sake of the diffuse reflection of light and UV in the vicinity of the reinforcing spacer 21, the projected area of the spacer 21 on the front plate 1a can be further reduced to relax the falling off of the luminance. Thereby the shade of the luminance can be reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a flat fluorescent lamp suitable for backlighting a liquid crystal display panel such as a liquid crystal television from the back side. , relates to a flat fluorescent lamp in which the shape of the reinforcing member for reinforcing the back plate is improved.

(Prior art) In recent years, LCD televisions have been developed and are becoming more popular.This type of LCD television requires an LCD panel to display the TV image and a backlight to illuminate the panel from the back. requires a function to illuminate the entire display surface of a predetermined area with a uniform brightness.

Conventionally, such backlights are made by arranging multiple U-shaped fluorescent lamps or small RI tube-shaped fluorescent lamps in parallel, and combining them with light reflecting surfaces and light diffusing surfaces to create various flat surfaces. Some are designed to obtain pyroxene distribution.

However, when using multiple fluorescent lamps like this, it is inevitable that the brightness near the lamps will be higher than other areas, and it is difficult to eliminate the overall uneven brightness. be.

In addition, when multiple fluorescent lamps are used, the structure for holding these lamps and the structure for connecting the power supply become complicated, resulting in an increase in the number of parts, an increase in the size of the device, and especially an increase in the thickness of the backlight itself. However, it has the disadvantage that it cannot be made thinner.

To solve this problem, Japanese Patent Laid-Open No. 62-
A flat fluorescent lamp as shown in Japanese Patent No. 208537 has been proposed.

This flat fluorescent lamp 1 is constructed as shown in FIGS. 10 to 12, and includes a front plate 1a made of a single transparent plate glass, and a back plate 2 made of a single plate glass of the same shape and size. , has a glass spacer 3 assembled into a rectangular frame having the same shape and size as the outer peripheral edges of these plates 1a and 2.

The front plate 1a has a fluorescent film 4 coated almost entirely on its inner surface as shown in FIG. 12, and its outer surface serves as a light emitting surface, and the back plate 2 has a light diffusing film 5 and a light reflecting film 1116 on its inner surface. are attached to the upper and lower 2FJ.

The front plate 1a and the back plate 2 are provided with a low melting point glass frit 7 at the front opening and rear opening of the spacer 3.
They are each airtightly joined to form a thin box-shaped airtight container 8 as shown in FIGS. 10 to 12.

Therefore, the front plate 1a faces the back plate 2 with the spacer 3 in between, and a discharge space 9 is formed between the two plates 1.degree.

In this discharge space 9, a pair of electrodes 10, 10, such as a hollow cathode type cold cathode, are arranged facing each other and separated from each other. , these mouth-shaped openings are opposed to each other.

Further, the pair of electrodes 10.10 has a pair of lead pieces 1i, ii integrally extending outward in the axial direction from one end in the axial direction, and the tip of each lead piece 11 is airtightly connected to the outside of the container 8. It is designed to extend and be connected to a power source (not shown).

In addition, the reference numeral 12 in FIGS. 10 and 11 is an exhaust pipe, and the closed container 8 having the discharge space 9 contains at least one rare gas such as xenon, krypton, argon, neon, helium, etc. In some cases, this rare gas and a predetermined amount of mercury are sealed.

In the flat fluorescent lamp 1 configured in this way, when a predetermined voltage is applied between the pair of electrodes 10 and 10,
Glow discharge occurs in both io and 1o IPH, and the glow fi electric current excites mercury atoms in the sealed container 8 to generate ultraviolet rays.This ultraviolet ray excites the fluorescent film 4 of the front plate 1a, and visible light is emitted. The light is emitted from the light emitting surface on the outer surface of the front plate 1a.

In addition, the ultraviolet rays generated inside the airtight container 8 are removed from the back plate 2.
The light is diffused and reflected by the light diffusing film 5 and the light reflecting film 6 and guided to the fluorescent light 14 side, thereby increasing the luminous efficiency in the fluorescent film 4.

Therefore, the entire front plate 1a emits light almost uniformly, so there is little unevenness in brightness.

(Problems to be Solved by the Invention) However, such conventional planar fluorescent lamps have a problem in that it is not easy to make them thin and lightweight.

That is, in order to enlarge the effective light emitting area of the flat fluorescent lamp 1, for example, when increasing the size of the front plate 1a, the front plate 1a is Of course, it is necessary to increase the thickness of the entire airtight container 8, such as the spacer 3, etc., which increases the weight of lff1, and has the disadvantage that it goes against the requirement for a thinner backlight.

In addition, when increasing the strength of the entire sealed container 8 by increasing the width of the spacer 3 without increasing the thickness of the front plate 1a, on the contrary, the front plate 1
This has the disadvantage that the effective light emitting area of a is reduced.

Therefore, in the conventional flat fluorescent lamp 1, as shown in FIGS. 10 and 12, a pair of electrodes 1o.

A pair of left and right glass reinforcing spacers 13.13 are interposed between the front plate 1a and the back plate 2 inside the axially intermediate portion of the plate 10, thereby reinforcing both the plates 1a, 2.

However, such conventional reinforcing spacers 13.1
3, as shown in FIG. 13, since its axial cross-sectional shape is rectangular, the light emitted within the discharge space 9 projects the shadow of the upper end of the reinforcing spacer 13.13 onto the front plate 1a. There is a problem in that the luminance decreases due to this, resulting in uneven luminance over the entire front plate 1a.

For example, as shown in FIG. 14(C), the reinforcing spacer 13.
In the relative brightness distribution of the front plate 1a when the width W of the short side of the rectangular cross section of 13 is 4 layers and the height of the discharge space 9 is 3a11, the brightness is flat as shown in FIG. 14(A). A rectangular luminance reduced part β occurs approximately in the middle of the peak part α on the reinforcing spacer 13, and this r1 degree reduced part β is formed by installing a light diffusing plate (not shown) on the front plate 1a. Even when they are brought into close contact, as shown in FIG. 14(B), they are only slightly relaxed.

The present invention has been made in consideration of the above circumstances, and its object is to provide a flat fluorescent lamp that can be made thinner, lighter, and less uneven in brightness.

[Structure of the invention]

(Means for Solving Problem 1) The present invention has been made by focusing on the fact that the problem with the conventional flat fluorescent lamp 1 is that the cross-sectional shape of the reinforcing spacer 13 is formed into a rectangular shape. Yes, that reinforcing spacer 13
The reason lies in the improved shape of the .

That is, in the present invention, a flat discharge space is surrounded by a front plate and a back plate arranged opposite to each other, and a frame-shaped spacer interposed between the outer peripheral edges of these plates, and in this flat discharge space, both front and rear plates are arranged oppositely. In a flat fluorescent lamp in which a reinforcing member is interposed between plates, the reinforcing member is
It is characterized in that its axial cross-sectional shape is tapered toward the front plate, and its side surfaces are curved.

(Function) Light and ultraviolet rays generated within the discharge space of the flat fluorescent lamp are diffusely reflected by the curved surface around the reinforcing member and output toward the front plate.

Moreover, since the reinforcing member has a tapered shape toward the front plate side, the projected area of the reinforcing member onto the front plate side is small, and as described above, light and ultraviolet rays are diffusely reflected by the curved surface of the reinforcing member. Therefore, it is possible to reduce the projected area of the reinforcing member projected onto the front plate, thereby alleviating a decrease in brightness and reducing uneven brightness.

One end of the reinforcing member that comes into contact with the back plate is not tapered, and the width of the contact with the back plate, that is, the contact area, can be increased, making the back plate thinner and lighter and reducing stress. Can be done.

(Example) Examples of the present invention will be described below based on FIGS. 1 to 9. Note that in FIGS. 1 to 9, parts common to those shown in FIGS. 10 to 13 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 1 is an exploded perspective view showing the overall configuration of an embodiment of the present invention, and the flat fluorescent lamp 20 of this embodiment is illustrated in FIGS.
A feature is that the conventional reinforcing spacer 13.13 shown in FIG. 13 is improved and constructed into a reinforcing spacer 21.

That is, as shown in FIG. 1, the reinforcing spacer 21 of this embodiment is made of a prismatic column fixed approximately in the center of the back plate 2, approximately parallel to the line connecting the pair of electrodes 10 and 10. The cross-sectional shape is formed into a substantially trapezoidal shape that tapers toward the front plate 1a side, thereby reinforcing the strength of the front plate 1a and the back plate 2.

As shown in FIGS. 2 and 3, the reinforcing spacer 21 has a trapezoidal side surface 21a having a concave arc surface 21a concave toward the axis.
, 21a, respectively.

Therefore, light and ultraviolet light generated around the reinforcing spacer 21 in the discharge space 9 are transmitted to the concave arc surface 21 of the reinforcing spacer.
It is diffusely reflected by a and 21a and output to the front plate 1a side.

Further, since the reinforcing spacers 21 are formed in a tapered shape that decreases toward the front plate 1a side, the projected area of the reinforcing spacers 21 projected onto the front plate 1a side is reduced, and as described above, the reinforcing spacers 21 Since light and ultraviolet rays are diffusely reflected around 21, the front plate 1a
The projected area of the reinforcing spacer 21 projected above is further reduced, the reduction in brightness is alleviated, and uneven brightness can be reduced.

For example, as shown in FIG. 4(C), the front and back plates 1
While forming the widthwise length of a and 2 to about 140 am,
The trapezoidal lower side d in the figure of the reinforcing spacer 21 is 10III&
, the relative brightness distribution on the front plate 1a when the upper side U is 4 m and the discharge space height h is 3 mm, as shown in Fig. 4 (A>), the flat peak part α is increased overall. Therefore, the overall brightness is increased compared to the relative brightness distribution of the conventional example shown in FIG. 14(A).

Further, when a light diffusing plate (not shown) is brought into close contact with the front plate 1a of such a flat fluorescent lamp 20, the relative luminance distribution is as shown in FIG. 4(B).
It is possible to significantly suppress the brightness reduction portion β in the portion corresponding to υ1.

Since the cross-sectional shape of the reinforcing spacer 21 is formed into a tapered trapezoid with its cross-sectional shape facing the front plate 1a side, it is possible to increase the contact width between the trapezoidal base and the back plate 2. .

Therefore, as shown in FIG. 5, the contact width of the conventional reinforcing spacer 13 (see FIG. 14(C)) with the back plates 1 and 2 is 4 MI, and the thickness of the back plate 2 is 4 MI. In the case of a layer, the maximum principal stress of the back plate 2 is about 500 Kg/Ci, but the contact width of the reinforcing spacer 21 with the back plate 2 of this embodiment is 10# as shown in FIG. 4(C). Therefore, when the thickness of the back plate 2 is reduced to 3 am, the maximum principal stress of the back plate 2 can be reduced to about 300 kg/d, making the flat fluorescent lamp 20 as a whole thin and lightweight. It is possible to increase the strength of the melon and strengthen the strength of the melon.

FIG. 6 shows a second embodiment of the present invention, in which the axial cross-sectional shape of the reinforcing spacer 31 is changed to the front plate 1a.
It is formed into a semicircular shape with a convex side (point m), and its left and right sides in the figure are formed into outwardly convex convex arc surfaces 31a, 31a, respectively, and its flat bottom is formed on the back plate 2. UIA is worn on the inside surface.

Therefore, also in this second embodiment, the reinforcing spacer 3
Light and ultraviolet rays generated in the discharge space 9 around the reinforcing spacer 31 are diffusely reflected by the convex arc surfaces 31a, 31a, and are output to the front plate 1a side.

For this reason, the projected area of the reinforcing spacer 31 projected on the front plate 1a side is reduced, so the front plate 1a
The above brightness unevenness can be reduced.

For example, as shown in FIG. 7(C), the widthwise length of the front and back plates 1a and 2 is approximately 140 JII, while the widthwise length t of the flat bottom surface of the reinforcing spacer 31 of the reinforcing member is 10#11. The relative luminance distribution of the front plate 1a when the upper end length j is 4aw is as shown in FIG. improved compared to

Furthermore, the relative 1lvl melon distribution when a light diffusing plate (not shown) is brought into close contact with the front plate 1a is shown in FIG. 7(B).
As shown in FIG. 3, the reduction in brightness in the portion β corresponding to the reinforcing spacer 31 can be significantly reduced compared to the case without a light diffusing plate.

As shown in FIG. 7(C), the contact width between the flat bottom surface of the reinforcing spacer 31 and the back plate 2 is 10a.
Therefore, even if the thickness of the back plate 2 is reduced to 3 ml+, as in the first embodiment, the maximum principal stress of the back plate 1-2 can be significantly reduced compared to the conventional example. can be reduced.

FIG. 8 is a schematic vertical cross-sectional view of a third embodiment of the present invention, and a flat fluorescent lamp 40 of this third embodiment has a pair of right and left reinforcing spacers 21 in the flat fluorescent lamp 20 of the first embodiment. The inner surfaces of the spacers 3a, 3a, which are opposite to the concave arc surfaces 21a, 21a of Since it is the same as that of the first embodiment, a duplicate explanation thereof will be omitted.

In this third embodiment of the planar fluorescent lamp 40, light and ultraviolet light around the reinforcing spacer 21 are absorbed by the left and right concave arc surfaces 21a, 21.
At the same time, light and ultraviolet rays are diffusely reflected by the concave arc inclined surfaces 41 and 41 of the spacers 3a and 3a.
t is generated, it is possible to reduce the tea drop at the central portion and the outer peripheral portion of the front plate 1a, and to reduce uneven brightness.

In addition, since the contact width with the back plate 2 can be doubled by the reinforcing spacer 21 and the spacers 3a, 3a, the back plate 2 can be made thinner and lighter, and the maximum principal stress can be reduced. It is possible to aim for

FIG. 9 is a sectional view w1 of the main part of the fourth embodiment of the present invention, and the flat fluorescent lamp 50 of this fourth embodiment is, for example,
In the flat fluorescent lamp 20 of the first embodiment shown in FIGS. A thin part 51a is formed by reducing the thickness in an arc shape at a part corresponding to the part of the shadow projected on the front plate 1a, and diffuse reflection of light in this thin part 51a is promoted to strengthen the reinforcing spacer 21. The aim is to reduce the decrease in brightness in the area corresponding to the area.

Although the fourth embodiment has been described as being applied to the first embodiment, the fourth embodiment may also be applied to the second and third embodiments, and there are no limitations on the shape of the reinforcing spacer. Not done.

(Effects of the Invention) As explained above, the present invention has an axial cross-sectional shape of a reinforcing member that is interposed between a front plate and a back plate and that reinforces both plates, so that the shape is tapered toward the front plate. Since it is formed into a tapered shape and its side surface is formed into a curved surface that diffusely reflects light and ultraviolet rays, it is possible to diffusely reflect light d3 and ultraviolet rays around this reinforcing member, reducing the decrease in brightness around this reinforcing member and increasing the brightness. It is possible to reduce unevenness.

Further, according to the present invention, since the contact width between the back plate and the reinforcing member can be expanded, the strength of the back plate can be increased, and as a result, the thickness of the back plate can be reduced by 411 mm. It is possible to aim for

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a first embodiment of a flat fluorescent lamp according to the present invention, FIG. 2 is a sectional view taken along line H-II after assembly in FIG. 1, and FIG. 3 is a main part of FIG. 2. Enlarged view, Figure 4 (A>, (B)
) shows the relative brightness distribution of the front plate corresponding to the configuration of the flat fluorescent lamp of the first embodiment shown in FIG. 4(C), and FIG. 5 shows the contact between the reinforcing spacer and the back plate. A graph showing the relationship between the width and the maximum principal stress of the back brake 1-,
FIG. 6 is a schematic vertical sectional view of the second embodiment of the present invention, and FIG. 7 (
A) and (B) are diagrams showing the relative luminance distribution of the front plate 1-, respectively, corresponding to the configuration of the flat fluorescent lamp of the second embodiment shown in FIG. 7(C), and FIG. 9 is a schematic vertical sectional view of the third embodiment, FIG. 9 is a longitudinal sectional view of the main part of the fourth 7m example of the present invention, FIG. 10 is a plan view of a conventional flat fluorescent lamp, and FIG. 11 is FIG. 12 is a cross-sectional view of the cutting line in FIG. 10, and FIG. 13 is a front view of the conventional example shown in .
-■ line end view, Fig. 14 (Δ), (B) is Fig. 14 (C
) is a graph showing the relative brightness distribution of the front plate corresponding to the conventional configuration shown in FIG. 1.20.30.40.50...Flat fluorescent lamp,
1a...Front plate, 2...Back plate, 3.
...Spacer, 9...Discharge space, 10...Electrode, 1
3゜21.31...Reinforcement spacer, 21a...Concave arc surface, 31a, 31a...Convex arc surface. Applicant's agent Hisashi Hatano Figure 13 Figure 13

Claims (1)

[Claims] A discharge space is surrounded by a front plate and a back plate arranged opposite to each other and a frame-shaped spacer interposed between the outer peripheral edges of these plates, and a reinforcing member is installed between the two plates in this discharge space. In the interposed flat fluorescent lamp, the reinforcing member has an axial cross-sectional shape tapered toward the front plate, and a side surface thereof is curved. shaped fluorescent lamp.