JP2006236954A - Flat lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat lamp capable of uniformly emitting light in a surface and having high energy efficiency. <P>SOLUTION: This flat lamp is so structured that a pulse voltage is sequentially applied to a discharge space divided into multiple ones. Thereby, uniform light emission in the surface can be provided when averaged in terms of time. In addition, since an emission spectrum is shifted to the long wavelength side, energy efficiency is enhanced. By increasing the number of divided spaces to three or more, the duty of the pulse voltage applied to each space is lowered below 50% and luminous efficiency at a wavelength of 254 nm being a central spectrum in a conventional mercury lamp is degraded. As a result, the emission spectrum is shifted to the long wavelength side centering a wavelength of 365 nm rather than a wavelength of 254 nm. In converting the light to visible light, a wasted rate in terms of energy is lowered, whereby energy efficiency is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fluorescent lamp or a mercury lamp, and more particularly to the structure and discharge system of a lamp having a flat discharge tube (hereinafter abbreviated as a flat lamp).

  In general, tube-shaped fluorescent lamps used for backlights of LCD TVs, etc., as the size of the backlight increases, the number of fluorescent lamps required increases. Attempts have been widely made to convert a flat fluorescent lamp into a single flat lamp. The flat lamp is disclosed in Patent Document 1 shown below, for example.

  In order to operate the flat lamp stably, it is necessary to partition the inside of the lamp into a plurality of spaces so that the discharge is not concentrated on one place and to discharge each space independently. In addition, by inserting this partition, there is also a function of suppressing a flat lamp having a large area from being crushed by a pressure difference.

JP 2003-217517 A

  Even if the inside of the flat lamp is divided into a plurality of spaces and each discharge is attempted independently, the intensity of the discharge may appear depending on the location, and it is difficult to cause a wide and uniform discharge in the plane. In addition, it has been proposed to divide a plurality of spaces into two sets and alternately apply a voltage to each electrode. According to this, it is said that ultraviolet light is efficiently emitted by causing pulse discharge with a duty of 50% in which applied voltage pulses alternate. However, even if the space to be divided is divided into two groups, there are cases where the intensity of light emission appears in each of the groups of spaces, and it is difficult to uniformly discharge the entire surface.

  An object of the present invention is to provide a flat lamp that can discharge uniformly over the entire surface and has high energy efficiency.

  According to the first aspect of the present invention, in the fluorescent lamp using a flat discharge tube, the internal space of the discharge tube is partitioned into at least three discharge spaces, and each of the partitioned discharge spaces is temporally different. A pulse voltage is applied at a timing.

  The invention according to claim 2 is characterized in that the pulse voltage is sequentially applied at different timings to a discharge space to be applied first and a discharge space adjacent to the discharge space.

  The invention described in claim 3 is characterized in that the pulse shape of the pulse discharge is a rectangular wave.

  The invention described in claim 4 is characterized in that a 436 nm light emission line of mercury is used as it is as blue light emission.

  According to the present invention, a voltage is applied to a large number of divided spaces at different timings and discharges are performed at different timings. Therefore, at each discharge timing, only one divided space emits light. To do. Therefore, when integrated and observed over time, light is emitted with the same average power from all spaces.

  However, since it is easy to set the number of repetitions of each discharge from several kHz to several tens of kHz, the number of frames required for a liquid crystal television or the like used is much higher than about 30 Hz. The amount of light emitted from the frame is substantially uniform throughout the entire surface.

  However, according to the present invention, the voltage is applied to the duty of the pulse voltage applied to one space (that is, one cycle of the pulse discharge) by increasing the number of spaces to be divided into three or more. The ratio of time) falls below 50%, and the luminous efficiency at a wavelength of 254 nm, which is the central spectrum of a conventional mercury lamp, is lowered. However, as a result, the wavelength shifts from the wavelength 254 nm to the longer wavelength side centered on the wavelength 365 nm. According to this, when converting into visible light, since the ratio of energy waste is reduced, there is an effect of improving energy efficiency.

  Note that when the duty of the discharge pulse is reduced in this way, the emission spectrum shifts to a longer wavelength side than 254 nm, for example, the document “Measurement Science and Technology, Vol. 11, pp. 547-553, 2000. Is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing an internal structure of a flat lamp 100 according to an embodiment of the present invention, and is a view of the flat lamp 100 as viewed from the front. Because of the internal structure, the substrate and cover glass of the flat lamp 100 are not shown. Referring to FIG. 1, a flat lamp 100 forms a rectangular thin space surrounded by an insulating plate 1a, an insulating plate 1b, an insulating plate 1c, and a common electrode 2, and the lamp emits light therein. Gas and mercury are enclosed. On the opposite side of the common electrode 2, ten electrodes 3a, 3b,... 3j (in the figure, descriptions of 3b to 3i are omitted) are attached to an insulating plate 1c, and adjacent electrodes are Slightly separated. Conductive wires 4a, 4b,... 4j (in the figure, descriptions of 4b to 4i are omitted) are connected to the electrodes 3a, 3b,... 3j, and a negative pulse voltage is applied. It has become so. Inside the fluorescent lamp 100, it is divided into ten elongated spaces by nine partition plates 5a, 5b,... 5i (the description from 5b to 5h is omitted in the figure). However, these spaces are not completely separated, and gas can come and go. These partition plates 5a, 5b,... 5i are insulators made of quartz, and also have a role of supporting the substrate (not shown) and the cover glass so as not to be crushed.

  Neon gas and a plurality of elongated discharge spaces 6a, 6b,... 6j formed by the partition plates 5a, 5b,. Argon gas is sealed, and a slight amount of mercury adheres to the inner wall. In the present invention, a pulse discharge is caused between the common electrode 2 and each of the electrodes 3a, 3b,... 3j to discharge in each discharge space 6a, 6b,. Generates ultraviolet light, which excites a phosphor (not shown) and emits the three primary colors of light, blue, green and red.

  The timing of the pulse voltage applied to each electrode 3a, 3b,... 3j in the flat lamp 100 is shown in FIG. In the graph of FIG. 2, the horizontal axis represents time, and the vertical axis represents voltage. As shown in the figure, in the flat lamp 100, the pulse voltage to be applied is a rectangular wave having a duty of 10%, and is sequentially applied to the electrodes 3a, 3b,... 3j. ing. However, after being applied to the electrode 3j, the process returns to the electrode 3a. As a result, the discharge spaces 6a, 6b,... 6j shown in FIG.

  That is, in the present invention, at a certain moment, a voltage is applied to only one of the ten discharge spaces 6a, 6b,... 6j, and only this discharges stably. However, the discharge spaces 6a, 6b,... 6j to be discharged are sequentially switched, so that when the light is averaged over time, the same amount of ultraviolet light is generated from all the discharge spaces 6a, 6b,. As a result, the flat lamp 100 can emit light uniformly in the plane.

  Note that the number of repetitions of the pulse voltage applied to one discharge space is about 10 kHz, which is about 300 times higher than the normal frame rate of 30 Hz in a liquid crystal television, for example. Even when observed in a flat plate, the flat lamp can obtain almost uniform light emission in the plane.

  However, the flat lamp 100 of the present invention has a rectangular wave with a duty of 10% with respect to one discharge space. Therefore, the emission spectrum is different from that of a conventional simple AC discharge mercury lamp. End up. An example of the emission spectrum of a conventional mercury lamp and the emission spectrum of the flat lamp 100 of the present invention are shown in FIG. In the conventional mercury lamp shown in (a), the strongest light emission is obtained at a wavelength of about 254 nm, and this light emission line reaches about 90% in terms of power. On the other hand, when a pulse discharge with a low duty is performed as in the present invention, as shown in (b), the emission intensity on the line on the longer wavelength side than 254 nm is greatly increased. The light emission intensity at 365 nm and wavelength 436 nm increases. This is described in Non-Patent Document 1.

  Therefore, in the flat lamp 100 of the present invention, phosphor materials (not shown) are different, and a red phosphor and a green phosphor that are colored efficiently by ultraviolet light having a wavelength of 300 to 365 nm are used. . On the other hand, for blue, the light emission line with a wavelength of 436 nm in the spectrum shown in (b) can be used as it is.

  As shown in FIG. 3B, in the flat lamp 100 of the present invention, the emission spectrum is shifted to the longer wavelength side than the conventional one, but as a result, the energy efficiency is improved. . That is, as shown in FIG. 4, a conventional fluorescent lamp using a mercury lamp generates three primary colors of light in the visible range from a wavelength of about 254 nm, and is therefore wasted even for blue having the shortest wavelength. Energy will be about 40%. On the other hand, in the flat lamp of the present invention, a large amount of ultraviolet light having a wavelength longer than 254 nm is generated. Since visible light is generated based on this, the proportion of wasted energy is greatly reduced. It became possible.

  The flat lamp according to the present invention can be used mainly for backlights for liquid crystal televisions.

It is a figure which shows the internal structure of the flat lamp which concerns on this Embodiment. It is the figure which showed the waveform and timing of the pulse voltage applied to each electrode in a flat lamp. (A) is the figure which showed the example of the emission spectrum of the conventional mercury lamp, (b) is the figure which showed the example of the emission spectrum of the flat lamp of this invention. It is a figure which shows the energy efficiency of the conventional mercury lamp.

Explanation of symbols

1a, 1b, 1c Insulating plate 2 Common electrode 3a, ... 3j Electrode 4a, ... 4j Conductor 5a, ... 5i Partition plate 6a, ... 6j Discharge space 100 Flat lamp

Claims (4)

In a fluorescent lamp using a flat discharge tube,
An inner space of the discharge tube is partitioned into at least three discharge spaces;
A flat lamp, wherein a pulse voltage is applied to each partitioned discharge space at different timings.   2. The flat lamp according to claim 1, wherein the pulse voltage is sequentially applied to the discharge space applied first and the discharge space adjacent to the discharge space at different timings.   3. The flat lamp according to claim 1, wherein the pulse shape of the pulse discharge is a rectangular wave. The flat lamp according to any one of claims 1 to 3, wherein an emission line of 436 nm of mercury is used as it is as blue light emission.

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