JP2003217519A - Gas discharge lamp, and information display system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive gas discharge lamp emitting light in plane shape, having high uniformity of light emission in spite of its simple structure, and to provide an information display system using the same. <P>SOLUTION: A plurality of electrodes (line-shapes negative electrodes and positive electrodes) 1, covered by a dielectric substance 4, arranged alternately and nearly in parallel with each other, are formed on the surface of one panel of a flat discharge container having opposing surfaces formed by a visible light transmissive front panel and a back panel, and a flat-shaped third electrode 2 is formed to the almost whole plane part of one panel chosen from the above flat panels. The third electrode 2 is grounded through a high resistance body 6 during normal lighting period of mainly discharging between the positive electrode and the negative electrode. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas discharge lamp and an information display system using the same, and more particularly to a dielectric barrier gas discharge whose basic feature is that electrodes are not exposed in a discharge space. The present invention relates to a lamp and an information display system configured using the lamp, such as general lighting such as indoor lighting and a back light source of a liquid crystal display.

[0002]

2. Description of the Related Art Liquid crystal displays are used as thin information display systems replacing CRTs, especially for personal computers and mobile phones. Further, recently, it has begun to be popularized for so-called TVs, which mainly display moving images.

Conventionally, the liquid crystal has a problem that the response speed for switching the display state is insufficient as compared with the CRT, and in particular, when the display is switched at high speed such as TV image, the displayed moving image is blurred.

In the liquid crystal display system, in order to solve this moving image blur, the development of a liquid crystal capable of faster response than before, and further, displaying black during the transition from one display state to the next display state. The so-called intermittent display has been developed, which sandwiches the state in which it is turned on. As a result, although it is incomplete, the problem that the moving image display is blurred is being improved.

However, as a countermeasure against the moving image blur caused by the high-speed response liquid crystal, the light transmission efficiency (opening efficiency) of the backlight is lower than that of the conventional liquid crystal, and in the intermittent display, the backlight is also displayed in the black display state. Continues to emit light,
There is also a serious problem regarding efficiency loss that the light utilization efficiency is lower than that of the conventional continuous display method.

As another method for improving the blur of moving images, an attempt has been made to intermittently display a straight tube cold cathode fluorescent lamp, which is a backlight, for intermittent display.

If this method can be used, it is possible to turn off the lamp during the black display period in the intermittent display method and prevent loss of light utilization efficiency. In addition, there is no need to use a specially high-speed liquid crystal with a low aperture ratio, which also prevents loss of light utilization efficiency.

[0008]

However, even with this method, the long straight tube cold-cathode fluorescent lamp corresponding to a large screen cannot be intermittently lit at a sufficient response speed. It has not been possible to realize intermittent display. Therefore, under the present circumstances, a moving image blurring countermeasure is taken by an intermittent display method using a high-speed liquid crystal, at the cost of a large reduction in efficiency.

According to the present invention, one end is attached to both ends of the conventional long thin tube shape.
A planar light emitting gas discharge lamp that can achieve high-speed intermittent lighting, which is not possible with a backlight using a cold cathode fluorescent lamp with individual electrodes, and has a high light emission uniformity with a low cost and simple configuration. And an information display system using the same.

[0010]

In order to solve the above-mentioned problems, the present invention is directed to two flat plates facing each other, that is, a flat discharge vessel having a translucent front plate and a back plate, and one of the two flat plates. A plurality of linear cathodes and anodes, which are alternately and substantially parallel to each other and are covered with an insulator, are formed on the inner plane of one of the flat plates, and one of the two flat plates is covered with the insulator. And a third electrode formed in a planar shape on the second electrode, and the third electrode is grounded via a high resistance body during a normal lighting period mainly for discharge between the cathode and the anode. Gas discharge lamp. It should be noted that the cathode and the anode mean that the potentials can be independently controlled, and the cathodes and the anodes are not limited to the same potential and the bipolar electrodes whose polarities change with time.

As a result, high-speed intermittent lighting can be realized,
Moreover, it is possible to obtain a planar light emission gas discharge lamp having a high uniformity of light emission while having an inexpensive and simple structure.

Further, according to the present invention, in order to display information, on the back surface of the screen control device for controlling transmission and non-transmission of visible light,
An information display system characterized by using the above gas discharge lamp as a light source.

Thereby, without sacrificing efficiency,
An information display system including a screen display device that simultaneously realizes clear moving image display and low power consumption can be obtained.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is such that a flat discharge vessel having two opposing flat plates and one of the two flat plates are alternately and substantially on the inner plane of one of the flat plates. A plurality of linear cathodes and anodes each formed in parallel and covered with an insulator; and a third electrode formed in a planar shape on one of the two flat plates so as to be covered with the insulator, The third electrode is a gas discharge lamp characterized in that it is grounded via a high-resistance body during a normal lighting period mainly for discharge between the cathode and the anode, and high-speed intermittent lighting. And has a function of realizing highly uniform planar light emission.

According to the second aspect of the present invention, the normal lighting period, the lighting pause period, and the lighting preparation period for assisting the discharge restart after the lighting pause period are set within an arbitrary unit time. The gas discharge lamp according to claim 1, wherein the third electrode is grounded through the low resistance body during the lighting preparation period.

Here, as in the invention described in claim 3,
Further, the third electrode has a switching means for switching between a state in which the third electrode is grounded via a high resistance during a normal lighting period and a state in which it is grounded via a low resistance during a lighting preparation period. The gas discharge lamp according to claim 2 is preferable.

It is to be noted that, as in the invention described in claim 4, the linear cathode and the linear anode can be independently operated for potential, and the linear cathode and the linear anode can be operated independently. It may be a gas discharge lamp.

According to a fifth aspect of the present invention, in the gas discharge lamp according to the fourth aspect, the linear cathode and the linear anode are bipolar electrodes whose polarities change with time. It may be.

According to a sixth aspect of the present invention, a constant potential is applied to the cathode and the anode during the lighting suspension period, and a high potential of the same phase is periodically applied to the plurality of cathodes and the anode during the lighting preparation period. It is preferable that the gas discharge lamp according to any one of claims 2 to 5 is characterized in that high potentials having different phases are periodically given to the cathode and the anode during the normal lighting period thereafter.

Further, as in the invention described in claim 7, in the normal lighting state, the current flowing through the gas discharge lamp is I
(RMS value), V is the peak voltage, and R is the resistance value of the resistor connecting the third electrode and the ground.
7. The value of h satisfies Rh ≧ 0.001 · V / I, and the resistance value Rl of the low resistance body satisfies Rl <0.001 · V / I. The gas discharge lamp according to any one of the above is suitable.

According to the invention described in claim 8, in a plurality of linear cathodes and anodes, the distance between each cathode and each anode adjacent thereto is substantially the same. The gas discharge lamp according to any one of items 1 to 7 is preferable.

Then, as in the invention described in claim 9,
The gas discharge lamp according to any one of claims 1 to 8, wherein the distance between each linear cathode and the anode is 5 mm or more and 100 mm or less.

Here, as in the invention described in claim 10, any one of claims 1 to 9 is characterized in that the difference between the number of the plurality of linear cathodes and the number of the linear anodes is one. It is more preferable to use the gas discharge lamp described above.

According to the invention described in claim 11,
A plurality of linear cathodes and anodes and a third electrode face each other 2
It is preferable that the gas discharge lamp according to any one of claims 1 to 10 is formed on the same flat plate side of the two flat plates.

Alternatively, the invention according to claim 12 is characterized in that the plurality of linear cathodes and anodes and the third electrode are formed on different flat plate sides of two facing flat plates. The gas discharge lamp according to any one of claims 1 to 10 may be used.

Further, as in the invention described in claim 13,
The gas discharge lamp according to any one of claims 1 to 12, wherein at least a part of the discharge vessel is formed with a phosphor that emits visible light when excited by ultraviolet rays. is there.

According to a fourteenth aspect of the present invention, in order to display information, a light source is provided as a light source on the back of a screen control device that controls transmission and non-transmission of visible light. The information display system is characterized by using a gas discharge lamp.

The invention according to claim 15 uses liquid crystal as a screen display device.
4 is an information display system described in 4.

According to the sixteenth aspect of the present invention, the discharge light emission is performed only in a part of the visible light transmitting period of the screen display device, and the discharge light emission is stopped during the other period. The information display system according to claim 14 or 15 is suitable.

FIG. 1 shows an embodiment of the present invention.
Will be described with reference to FIG.

Although the present invention does not limit the material and shape of the discharge vessel, the most realistic one is the flat (flat) discharge vessel made of glass. The embodiment described in 1. uses a flat plate discharge vessel made of glass.

(Embodiment 1) FIG. 1 is a cross-sectional view of a discharge vessel showing an electrode arrangement of a gas discharge lamp according to the present embodiment, and shows a plurality of linear cathodes which is the most basic concept of the present invention. It is sectional drawing of a discharge vessel which shows arrangement | positioning of the anode and the 3rd electrode grounded via desired resistance. In FIG. 1, 1 is a plurality of linear cathodes and linear anodes, 2 is a third electrode, and 3 is a discharge vessel having two flat plates facing each other, that is, a translucent front plate (upper) and a rear plate (lower). 4 is the electrode 1
A dielectric 5 and a fluorescent material 5 respectively covering the above.

The linear cathode and the linear anode 1 are formed on the back plate side in a state of being covered with the dielectric 4 and not exposed to the inner and outer spaces of the discharge vessel 3. Adjacent electrodes are arranged at substantially equal intervals. The third electrode 2 is grounded via a desired resistance and, like the other electrodes, is formed on the rear plate side while being covered with a dielectric.

In FIG. 1, the cathode, the anode, and the third electrode are all formed on the back plate side. However, the present invention is not limited to this, and either the cathode, the anode, or the third electrode is formed. May be formed on the front plate side, or both may be formed on the front plate side.

The desired resistance means normal lighting (discharging).
The period indicates the high resistance body 6 and the lighting preparation period indicates the low resistance body 7, and a switching mechanism 8 is provided as a means for switching the period when necessary.

Reference numeral 9 is a light diffusing sheet for correcting a slight unevenness of light emission at the time of discharge, and 10 is a light condensing sheet for condensing radial light emission as much as possible in front of the lamp.

An appropriate gas is enclosed in the discharge vessel.

As for the linear electrodes, the case of two cathodes and two anodes is shown in FIG. 1, but the present invention is not limited to this, and the same effect can be obtained in a larger number. However, it is preferable that the number of cathodes and the number of anodes are set to different values because more stable operation is possible. That is, when the number of linear cathodes is m and the number of linear anodes is n, the difference between m and n is one difference, that is, m−n = ±
It is better to set it to 1.

Further, the cathode and the anode mean that the potentials can be independently controlled, and they are not limited to the same potential and the bipolar electrodes whose polarities change with time.

As the material of the linear electrode, various metals such as Ag, Ni and Al and ITO which is a transparent conductor were tried, but in any case, the present invention is not limited and effective. However, when aiming for a uniform light source of visible light, IT is used for the linear electrode material.
It is more preferable to use O. With regard to the width and thickness of the linear electrode, it is preferable that the width and thickness are as thin as possible.

Moreover, it is difficult to limit the numerical value because it depends on the type and pressure of gas and the properties of the dielectric material covering the electrode, but within the range of implementation, metal or IT is used for the electrode.
When O is used, the width is 0.1 mm to 5 mm and the thickness is 0.1.
About 10 μm to 10 μm was available. Further, the width and the thickness of each linear electrode are not limited to be the same. For example, when the width of each of the two ends of the linear cathode in the present embodiment is set to about 50% of that of the others, it is more suitable for uniforming the overall brightness.

Next, regarding the distance between the adjacent linear electrodes, it is preferable that the distance is large in order to realize high luminous efficiency. However, it becomes difficult to discharge and emit light with all the linear electrodes, which is the basic function of the surface emitting lamp of the present invention. In addition, it is difficult to realize high brightness. Distance between electrodes is 5 mm to 100 m
m were available.

Regarding the enclosed gas, Xe 100%,
Xe30% -Ar70%, Ne90% -Ar10%, Xe100%
+ Hg, Xe30% -Ar70% + Hg, Ne90% -Ar10%
It carried out about 6 kinds of + Hg. As an example, the above six types were carried out, but there is no particular limitation on the type of gas as long as it contains at least a rare gas. The usable gas pressure range was about 10 torr to 200 torr.

Next, regarding the distance between the substrate (rear plate) on which the linear electrodes are formed and the other substrate (front plate), that is, the internal height of the discharge vessel, at least 0.3 mm or more is required. However, below this, uniform discharge and light emission could not be achieved. Considering the brightness of the discharge lamp, 1
The usable range was about 0 mm or less.

With the above configuration, 16.7 ms is set as one field, and among them, the lighting preparation period T1, the normal lighting period T2, and the lighting suspension period T3 (T1 + T2 + T3 = 1)
6.7 ms) as a parameter, a voltage having an appropriate drive waveform was applied to each linear electrode, and an experiment was carried out in which the lamp was discharged and emitted.

T1: 0 to 1 ms, T2: 0.7 to 16 m
Under the conditions of s and T3: 0.7 to 16 ms, it was possible to realize a sharp intermittent lighting in which the discharge light emission restart was 0.1 ms or less. Further, under any condition, discharge emission was generated between all the linear electrodes, and uniform surface emission could be realized as a whole.

For comparison, an experiment was conducted in which the third electrode was grounded without a high resistance element even during the normal lighting period, but it was found that a large luminance unevenness was generated and the setting was inappropriate.

On the contrary, it was found that even under the condition that the third electrode is grounded through the high resistance during the lighting preparation period, flicker discharge light emission occurs during the lighting preparation period, which is not preferable.

The pulse waveform shown in FIG. 2 is used as the drive waveform, but the drive waveform is not limited to this.

Further, a constant potential is applied to the cathode and the anode during the lighting suspension period, a high potential of the same phase is periodically applied to the plurality of cathodes and the anode during the lighting preparation period, and then the cathode and the anode are operated during the normal lighting period. A more stable discharge characteristic can be obtained by using a driving method in which high potentials having different phases are periodically applied to the anode.

Further, an experiment was conducted using the respective resistance values for limiting the low resistance value during the lighting preparation period and the high resistance value during the normal lighting period as parameters. As a result, when the peak current I flowing through the gas discharge lamp, the peak voltage V, and the resistance value R of the resistor connected to the third electrode and the ground are Rh, the resistance value Rh of the high resistor is Rh ≧ 0.001. When the V / I and the resistance value Rl of the low-resistance element satisfy the condition of Rl <0.001 V / I, discharge discharge of the lamp is stable, and intermittent lighting having sufficiently steep lighting restart characteristics can be realized. I understood.

Further, it has been found that when the above conditions are not satisfied, the discharge light emission is flickering, which is not preferable as a lamp. Experiments were conducted under various conditions such as the number of electrodes and gas species, but similar results were obtained.

Up to this point, it has been described that the resistance connected to the third electrode is controlled to realize the intermittent lighting. However, the potential control of the third electrode, for example, the third electrode is normally turned on at a low potential during the lighting preparation period. It was confirmed that the same effect could be obtained by setting a high potential during the period.

As described above, according to the present embodiment, it is possible to obtain a gas discharge lamp which is a uniform surface emitting light source capable of intermittent lighting with a very fast response.

(Second Embodiment) Next, a case where the gas discharge lamp of the present invention is used as a back light source of a transmissive liquid crystal display will be described. The gas discharge lamp of the present invention is suitable as a back light source of a liquid crystal display, capable of performing a sufficiently high-speed intermittent lighting for displaying a moving image such as a TV, and realizing a surface light source with high brightness and high light emission uniformity.

First, when the electromagnetic noise of the lamp becomes an obstacle when combined with the liquid crystal, it can be dealt with by covering the entire outside of the gas discharge lamp with a grounded one.

In the liquid crystal display, in order to obtain a clear moving image, a black display of 5 ms is added for each field,
A comparative experiment was performed in which a video signal was displayed during the remaining time of 11.7 ms.

As an example of the present invention, a combination of the conventional TN liquid crystal and the gas discharge lamp of the present invention which is intermittently lit as a backlight was used.

As a comparative example, a combination of an ultra-high-speed response liquid crystal having a low aperture ratio and a conventional straight tube cold cathode fluorescent lamp which is always turned on as a backlight (Comparative Example 1), a conventional TN liquid crystal, Experiments were also conducted on a backlight combined with a conventional straight tube cold cathode fluorescent lamp (Comparative Example 2).

The same moving image signal was applied to the above three types of liquid crystal display systems to evaluate the sharpness of the display.

According to the example of the present invention, it was confirmed that a very clear moving image display was obtained. In (Comparative Example 2), the responsiveness of the conventional straight tube lamp was insufficient, so that the display was considerably blurred. In addition, (Comparative Example 1) was inferior to the example of the present invention, but a clear moving image was displayed as compared with (Comparative Example 2).

Next, the power consumption for obtaining the same screen brightness was compared with the above three types.

Assuming that the embodiment of the present invention is 100, (Comparative example 2) was 130 and (Comparative example 1) was 350.

From the above results, it can be said that the information display system according to the embodiment of the present invention, for example, the liquid crystal display system can achieve both clear moving image display and low power consumption (high efficiency). An advantageous effect is acquired.

[0065]

As described above, according to the present invention, high-speed intermittent lighting, which cannot be realized by a conventional backlight of a cold cathode fluorescent lamp having one electrode at each end of a long thin tube, can be performed uniformly. A gas discharge lamp and an information display system using the same that can be realized as highly planar light emission can be obtained. For example, in a liquid crystal display, a clear moving image display and low power consumption can be achieved without sacrificing efficiency. An epoch-making effect that it can be provided at the same time is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a discharge vessel showing an electrode arrangement according to an embodiment of the present invention.

FIG. 2 is a lamp drive waveform diagram according to an embodiment of the present invention.

[Explanation of symbols]

1 electrode (linear cathode and anode) 2 Third electrode 3 discharge vessel 4 Dielectric 5 phosphor 6 High resistance body (for normal lighting period) 7 Low resistance body (for lighting preparation period) 8 switching mechanism 9 Light diffusion sheet 10 Light collecting sheet

Continued front page    (72) Inventor Hiroko Imamura             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Jun Kuwata             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 2H091 FA41Z FD11 GA01 LA18                       LA30 MA10

Claims (16)

[Claims] 1. A flat discharge vessel having two flat plates facing each other, and a plurality of wires formed alternately and substantially parallel to each other on an inner plane of one of the two flat plates and covered with an insulator. A cathode and an anode, and a third electrode formed in a planar shape on one of the two flat plates so as to be covered with an insulator, wherein the third electrode is between the cathode and the anode. The gas discharge lamp is characterized in that it is grounded via a high resistance body during a normal lighting period mainly for discharge in. 2. A normal lighting period, a lighting quiescent period, and a lighting preparation period for assisting discharge resumption after the lighting quiescent period are set within an arbitrary unit time, and the third electrode is configured to perform the lighting preparation period. The gas discharge lamp according to claim 1, wherein the inside is grounded via a low resistance body. 3. A switching means for switching between a state where the third electrode is grounded via a high resistance body during a normal lighting period and a state where it is grounded via a low resistance body during a lighting preparation period. The gas discharge lamp according to claim 2, wherein: 4. The gas discharge lamp according to claim 1, wherein the linear cathode and the linear anode can be operated independently of each other. 5. The gas discharge lamp according to claim 4, wherein the linear cathode and the linear anode are bipolar electrodes whose polarities change with time. 6. A constant potential is applied to the cathode and the anode during the lighting suspension period, high potentials of the same phase are periodically applied to the plurality of cathodes and the anode during the lighting preparation period, and the cathode and the anode are subsequently applied during the normal lighting period. The gas discharge lamp according to any one of claims 2 to 5, wherein high electric potentials having different phases are periodically applied to and. 7. When the current flowing through the gas discharge lamp is I (effective value), the peak voltage is V, and the resistance value of the resistor connected to the third electrode and ground is R in the normal lighting state,
The resistance value Rh of the high resistor is Rh ≧ 0.001 · V / I
And the resistance value Rl of the low resistance is Rl <
3. It satisfies 0.001 · V / I.
7. The gas discharge lamp according to any one of 6 to 6. 8. The gas discharge according to claim 1, wherein in each of the plurality of linear cathodes and anodes, the distance between each cathode and each anode adjacent thereto is substantially the same. lamp. 9. The distance between each linear cathode and the anode is from 5 mm to 100 mm, inclusive.
A gas discharge lamp according to any one of 1. 10. The method according to claim 1, wherein the difference between the number of linear cathodes and the number of linear anodes is one.
A gas discharge lamp according to any one of 1. 11. The plurality of linear cathodes and anodes, and the third electrode are formed on the same flat plate side of the two flat plates facing each other. Gas discharge lamp. 12. The plurality of linear cathodes and anodes and the third electrode are formed on different flat plate sides of the two flat plates facing each other. Gas discharge lamp. 13. The gas discharge lamp according to claim 1, wherein a phosphor that emits visible light when excited by ultraviolet rays is formed at least partially on the inner surface of the discharge vessel. 14. Transmission of visible light for displaying information,
An information display system, characterized in that the gas discharge lamp according to any one of claims 1 to 13 is used as a light source on the back of a screen control device that controls non-transmission. 15. The information display system according to claim 14, wherein a liquid crystal is used as the screen display device. 16. The discharge light emission is performed only in a part of the visible light transmitting period of the screen display device, and the discharge light emission is stopped during the other period.
Information display system described.