JPH0433202A - Illumination device - Google Patents

Abstract

PURPOSE:To densely arrange luminous sections, improve brightness, and unify brightness by arranging end sections of fluorescent lamps in addition to space regions surrounded by bent sections of the bent type fluorescent lamps and linear portions connected to them. CONSTITUTION:Linear sections 7b... of adjacent lamps are inserted and arranged into spaces 9 surrounded by U-shaped bent sections 5 and linear sections 6a, 6b connected to them of the U-shaped cold-cathode fluorescent lamps 3a, 3b, 3c, 3d, thus luminous sections exist in the space sections 9. Regions of the end sections of the lamps where electrodes 8a, 8b are arranged are folded toward the bottom face of a casing 1, the luminous sections inserted and arranged into the space sections 9 are located near the bent sections 5 surrounding the spaces 9 and becomes similar to a planar light source, brightness is improved, and illuminance distribution is unified. Bent end sections 7a, 7b of the lamps 3a, 3b, 3c, 3d are guided from the bottom face of the casing 1, wiring cords 12 can be connected to guide end sections, and workability is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a lighting device suitable for backlighting of a liquid crystal display device, etc. Regarding equipment.

(Prior art) Liquid crystal meters used in automobile instrument panels display characters and figures on the liquid crystal surface by shining light from the back of the liquid crystal.
A lighting device is required that can illuminate a liquid crystal surface having a predetermined extent with uniform brightness as a whole.

Conventionally, this type of backlight includes a hot cathode or cold cathode fluorescent lamp housed as a light source in a casing that has a reflective surface on its inner surface, and the light from this lamp is reflected by the reflective surface and then exits from the opening of the casing. A lighting device that emits light is used.

When hot cathode or cold cathode fluorescent lamps are used as the light source, these fluorescent lamps have superior luminous efficiency, generate less heat, and have a longer lifespan than incandescent lamps.
Moreover, since it has a long discharge path, the light emitting area is large and the light distribution tends to be even. In addition, in the case of such a fluorescent lamp, it is easy to configure the discharge path into a bent shape, such as a U-shape or a W-shape. Another advantage is that it is easy to irradiate evenly.

By the way, in recent lighting devices used as backlights, there is an increasing demand for illuminating the entire liquid crystal surface with uniform brightness and even brighter light. It is conceivable to accommodate several fluorescent lamps and to arrange these lamps as closely as possible.

For example, by arranging a large number of straight tube fluorescent lamps in close proximity to each other, the light emitting parts can be arranged densely, the uniformity of the illuminance distribution can be increased, and the brightness can also be improved.

However, if a large number of straight tube fluorescent lamps are used,
Since there are a large number of electrodes, the structure for connecting these electrodes to a power source becomes complicated.

On the other hand, when using bent fluorescent lamps such as U-shaped or W-shaped, the straight parts of these lamps emit light in the same way as straight tube fluorescent lamps, so it is possible to reduce the number of lamps used. Although the number of lamps is small, it is possible to expect the same function as when using a large number of the above-mentioned straight tube fluorescent lamps.

(Issue 1i to be Solved by the Invention) However, in the case of a bent fluorescent lamp, the area surrounded by the bent part and the straight line part connected thereto becomes a space. In other words, in a bent fluorescent lamp, a straight bulb is bent and formed into a U-shape or W-shape, so there are restrictions on the radius of curvature due to processing, and the distance between the opposing straight parts connected to the bent part is limited. There is a limit to how small it can be.

For this reason, a space is created in the area surrounded by the bent part and the straight line part connected thereto, and this part does not become a light emitting part, which tends to cause variations in the light emission distribution over the entire surface.

In order to solve this problem, if another fluorescent lamp is inserted and placed in the area surrounded by the bent part of the bent fluorescent lamp and the straight part connected to it, the space will be filled and the entire area will be covered. The density of the light emitting part is improved and the uniformity of brightness is increased.

However, when the end of another lamp is inserted into the space surrounded by the bent part as described above, the electrode part installed at the inserted end is not effective for emitting light, and is used as a non-light emitting part or a low light emitting part. A light emitting part is generated in a space surrounded by a bent part.

In addition, an electrode is arranged at the end of the lamp, and this electrode is connected to the ballast on the power supply side via a wiring cord, but in this case, the space surrounded by the bent part of one bent lamp If the end of another lamp is inserted into the end of the lamp, it becomes troublesome to handle the wiring cord connected to the electrode installed at the insertion end. In other words, there is a risk that the wiring hood connected to the electrode will block the light emitted from the lamp, and if you try to route the wiring cord at the end of the bulb, the space is narrow, making it difficult to work. If you try to secure a space for wiring, this becomes a non-light-emitting part, which causes problems such as deterioration of brightness and light distribution, and also complicates the structure for wiring the wiring cord.

The present invention was developed based on these circumstances, and the light emitting parts can be arranged densely to improve brightness and provide uniform brightness, and the wiring cords connected to the electrodes can be easily disposed of. The purpose of this invention is to provide a lighting device that can be used for various purposes.

[Structure of the invention]

(Means for Solving the Problems) According to the present invention, at least one of the plurality of low-pressure discharge lamps is a bent lamp having a bent part in the middle of the bulb, and the bent part of the discharge lamp and the bent part are connected to and face each other. The end of another discharge lamp is arranged in the space surrounded by the straight part, and the end of the other discharge lamp is bent toward the bottom of the casing, and an electrode is sealed in this bent end. It is characterized in that the end portion is led out from the bottom of the casing.

(Function) According to the present invention, the ends of other fluorescent lamps are placed in the spatial area surrounded by the bent part of the bent fluorescent lamp and the linear part connected thereto, so that this space can emit light. filled in by the department. In this case, the ends of the other discharge lamps placed in this space are bent toward the bottom of the casing, and the electrodes are sealed in the bent ends, so that the ends of the lamps that are non-light emitting parts or low light emitting parts are left in the space. Since the light emitting parts are densely arranged over the entire surface, the brightness is improved and the uniformity of the brightness is also increased. Furthermore, since this bent end is led out from the bottom surface of the casing, the wiring cord can be connected and routed from the back surface of the casing.

(Example) The present invention will be described below based on an example shown in FIGS. 1 to 3.

In the figure, reference numeral 1 denotes a casing, which is made of synthetic resin such as polycarbonate or metal, and is formed into a shallow dish shape. The entire inner surface of the casing 1 is a reflective surface 2.

A plurality of cold cathode fluorescent lamps 3a, 3b, 3c and 3d are accommodated in such a casing 1.

These cold cathode fluorescent lamps 3a, 3b, 3c and 3d
In this embodiment, U-shaped lamps are used in each case.

Each of these lamps 3a, 3b, 3c and 3d has a bulb 4 bent into a U-shape. That is, the valve 4 includes a U-shaped bent part 5, a straight part 6a connected to both ends of the bent part 5 so as to be substantially parallel to each other,
6b. These straight portions 6a, 6b have different lengths, and each end has bent ends 7a, 7b bent in a direction approximately perpendicular to the plane passing through the bent portion 5 and the straight portions 6a, 6b. It is formed. Cold cathode type electrodes 3a are provided at these bent ends 7a and 7b.

8b is sealed.

Note that the inner surface of the bulb 4 is coated with a phosphor film (not shown).
The inside of the valve 4 is filled with a predetermined amount of mercury and a starting rare gas such as argon or xenon.

The four U-shaped cold cathode fluorescent lamps 3a, 3b, s3c and 3d formed as described above are arranged side by side in a plane, and the two U-shaped cold cathode fluorescent lamps 3a and 3b, 3c and 3d are arranged alternately.

To explain in more detail, each of the four U-shaped cold cathode fluorescent lamps 3as 3b, 3c and 3d has a space 9 formed in a region surrounded by a U-shaped bent part 5 and straight parts 6a and 6b connected thereto. has been done. The two U-shaped cold cathode fluorescent lamps 3a and 3b and the two U-shaped cold cathode fluorescent lamps 3c and 3d are respectively arranged such that one straight section of the other lamp is inserted into the space 9 of one of the lamps.

In other words, if we take two U-shaped cold cathode fluorescent lamps 3a and 3b as an example, the shorter straight portions 6b, 6b of the other lamp are inserted into the space 9.9 of each lamp. be.

For this reason, four U-shaped cold cathode fluorescent lamps 3a, 3b are provided.
, 3c and 3d are arranged so as to be substantially parallel to each other and are arranged close to each other.

Each of these lamps is housed in the casing 1, and its bent end 7a17b is directed toward the bottom of the casing 1, and is led out from a lead-out hole 10 formed in the bottom wall.

Lead wires 11 connected to the electrodes extend from this lead-out end, and wiring cords 12 are attached to the outside of the bottom surface of the casing 1 to these lead wires 11.
・is connected. These wiring cords 12... are connected to a power supply side ballast (not shown).

A light diffusing and transmitting plate 15 is attached to the upper opening of the casing 1. The light diffusing and transmitting plate 15 is made of acrylic resin or the like and has a milky white color and has a light diffusing effect.

The operation of the lighting device having such a configuration will be explained.

When each U-shaped cold cathode fluorescent lamp 3a% 3b% 3c and 3d is lit, this lamp 3a%3b,
The light emitted from 3c and 3d is directed directly and after being reflected by the reflective surface 2 of the casing 1, goes to the opening of the casing 1, passes through the light diffusing and transmitting plate 15 provided in this opening, and is irradiated to the outside. be done.

In this case, in this embodiment, the four U-shaped cold cathode fluorescent lamps 3as 3b, 3c, and 3d are arranged alternately, so that the straight portion 6a of each lamp.

6b are lined up in parallel with no gaps, and the light distribution is good.

Moreover, U-shaped cold cathode fluorescent lamp 3as 3bs3c
and 3d are arranged so that the adjacent lamp straight part 7b enters the space 9 surrounded by the U-shaped bent part 5 and the straight parts 6a and 6b connected thereto, so that There will also be a light emitting section. Moreover, since the region at the end of the lamp where the electrodes 8 a s 8 b are arranged is bent toward the bottom surface of the casing 1 , the light emitting section inserted and arranged in the space 9 is located at the bend 5 surrounding the space 9 . It is possible to reduce the occurrence of gaps between the two.

Therefore, there are no non-light emitting parts or low light emitting parts in the space 9, and the casing 1 is completely filled with light emitting parts. This makes it close to a flat light source, improving brightness and making the illuminance distribution even.

Therefore, the light diffusing and transmitting plate 19 shines brightly over the entire surface.
Brightness unevenness is eliminated. Furthermore, since the lamps can be arranged close to each other, the casing 1 can also be made smaller.

Since the bent ends 7 a s 7 b of each lamp are led out from the bottom surface of the casing 1, the wiring cord 12 can be connected to this led end, and the wiring cord 12 can be routed on the back surface of the casing 1. It is easy to work with, and there is no need to worry about wiring cords blocking light.

Note that the present invention is not limited to the above embodiments.

That is, although the above embodiment describes an illumination device using four U-shaped cold cathode fluorescent lamps, the lamps used are not limited to the above embodiment.

For example, FIG. 4 shows a second embodiment of the present invention, in which one U-shaped cold cathode fluorescent lamp 20 and one straight tube cold cathode fluorescent lamp 21 are used. . In this case, in the space 9 surrounded by the U-shaped bent part 5 of the U-shaped cold cathode fluorescent lamp 20 and the straight parts 6a and 6b connected thereto,
One end of the straight tube cold cathode fluorescent lamp 21 is inserted and arranged, and this end is bent toward the bottom of the casing 1.

Both ends of the U-shaped cold cathode fluorescent lamp 20 and one end of the straight tube cold cathode fluorescent lamp 21 are not bent ends, but are led out to either side of the casing 1.

Even in this case, the arrangement density of the light emitting parts is increased.

Further, the third embodiment of the present invention shown in FIG.
This is an example in which a letter-shaped cold cathode fluorescent lamp 30, two U-shaped cold cathode fluorescent lamps 31a and 31b, and one straight-tube cold cathode fluorescent lamp 32 are used.

Furthermore, the present invention is not limited to cold cathode fluorescent lamps, but may also be applied to hot cathode fluorescent lamps.

Furthermore, the present invention is not limited to fluorescent lamps, and may be applied to rare gas discharge lamps.

Furthermore, the lighting device of the present invention is not limited to being used as a backlight for a liquid crystal display device.

〔Effect of the invention〕

As explained above, according to the present invention, the ends of other fluorescent lamps are arranged in the space area surrounded by the bending part of the bending type fluorescent lamp and the linear part connected thereto, so that this space part emits light. filled in by the department. In this case, the ends of the other discharge lamps placed in this space are bent toward the bottom of the casing, and the electrodes are sealed in the bent ends, so that the ends of the lamps that are non-light emitting parts or low light emitting parts are left in the space. Since the light emitting parts are densely arranged over the entire surface, the brightness is improved and the uniformity of the brightness is also increased. In addition, since the bent end of the lamp is led out from the bottom of the casing, the wiring cord can be connected and routed from the back of the casing, improving work efficiency and eliminating problems such as the wiring cord blocking light.

[Brief Description of the Drawings] Figures 1 to 3 show a first embodiment of the present invention, with Figure 1 being an exploded perspective view of the entire lighting device, and Figure 2 being a plan view showing the arrangement of lamps. , FIG. 3 is a sectional view taken along the line-m in FIG. 2, FIG. 4 is a plan view of a lamp arrangement showing a second embodiment of the present invention, and FIG. FIG. 3 is a plan view of lamp arrangement. 1... Casing, 2... Reflective surface, 3a, 3b. 3c, 3d... U-shaped cold cathode fluorescent lamp, 4...
Valve, 5... Bent part, 6as 6b... Straight part,
7a. 7jb...bent end, 8a, 8b...cold cathode, 10
...Wiring diameter, hole, 12...Wiring cord, 20...U-shaped cold cathode fluorescent lamp, 21...Straight tube cold cathode fluorescent lamp, 30...W-shaped cold cathode fluorescent lamp Lamp, 31a. 31b... U-shaped cold cathode fluorescent lamp, 32... Straight tube cold cathode fluorescent lamp. Applicant's Representative Patent Attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A lighting device in which a plurality of low-pressure discharge lamps are housed in a casing, and light emitted from the low-pressure discharge lamps is emitted to the outside through a light diffusing and transmitting plate provided in an opening of the casing. , At least one of the plurality of low-pressure discharge lamps is a bent discharge lamp having a bent part in the middle of the bulb, and there is no other space in the space surrounded by the bent part of the discharge lamp and the straight part facing the bent part. The end of the discharge lamp is arranged, the end of the other discharge lamp is bent toward the bottom of the casing, the bent end is sealed with an electrode, and the bent end is led out from the bottom of the casing. A lighting device featuring: