JP2007329042A - Fluorescent lamp and liquid crystal back light apparatus using the same as light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: infrared ray in the range used by an infrared remote controller is emitted at start in the former fluorescent lamp, and the infrared remote controller operates incorrectly near the place where a number of fluorescent lamps, such as back lights of a large liquid crystal television set, are used. <P>SOLUTION: Krypton of about 0.5% is added into buffer gas which is used in stead of argon gas and neon gas used usually, so that starting performed by argon gas emitting a large quantity of infrared ray at beginning of discharge especially at cold time is replaced by krypton gas emitting a small quantity of infrared ray. Thus, the wavelength shifts to a short wavelength side where sensitivity of the infrared remote controller is low, thereby an effect on the infrared remote controller is reduced to prevent malfunction and non-operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluorescent lamp used as a light source for a backlight device of a liquid crystal display device, and more specifically, an infrared remote controller (hereinafter abbreviated as an infrared remote controller) is provided when the fluorescent lamp is activated. There are cases where malfunctions or malfunctions occur in other devices, such as televisions, DVD recorders, air conditioners, etc., and are related to countermeasures against such malfunctions.

  First, the cause of the malfunction of the infrared remote controller due to the light from the fluorescent lamp will be explained. When the fluorescent lamp is started, the tube wall temperature of the fluorescent lamp is low, so the amount of mercury vapor in the fluorescent lamp is relatively small and This is because start-up is performed with a buffer gas such as argon gas. In this case, when the fluorescent lamp is started, infrared light in the vicinity of 910 to 920 nm is emitted from the fluorescent lamp.

  That is, since the temperature rise at the start of the fluorescent lamp is mainly due to the heat of the electrode section, it takes a long time for the fluorescent lamp to warm up due to the lengthening of the fluorescent lamp. If the time until the fluorescent lamp is warmed becomes long, the time during which infrared light is radiated becomes long, and as a result, the possibility of causing the malfunction is increased.

  Therefore, sensitivity is generated in the receiver of the infrared remote controller having sensitivity to wavelengths in this range, and malfunction is caused in the remote controller. Here, in recent years, the spread of large-sized liquid crystal televisions, personal computer monitors, etc. has been remarkable, and fluorescent lamps used as this type of backlight device have also become larger and more numerous. It is said that this type of malfunction is also increasing.

As a solution to this type of problem, first, the outer surface of the glass bulb contains a near-infrared blocking substance that blocks the transmission of near-infrared rays, and second, the inner or outer surface of the glass bulb. , Means for forming a near-infrared blocking layer for blocking the transmission of near-infrared light, and thirdly, means for coating a film containing a near-ultraviolet blocking material for blocking the transmission of near-ultraviolet light on the outer surface of the glass bulb It has been known.
Japanese Patent Laid-Open No. 04-079149

  In the above-described conventional infrared ray shielding method, the first means uses, for example, a transition metal ionized with iron or the like to absorb near infrared rays (1000 nm). When a fine powder is dispersed in soda glass and a glass bulb is formed from this glass, a fluorescent lamp that does not emit near-infrared light at startup can be obtained.

  However, any of the first to third near-infrared emission preventing means described above inevitably takes measures against the emission of near-infrared rays from the fluorescent lamp when the fluorescent lamp is cold. Therefore, in the second means, an interference filter in which high refractive index films and low refractive index films are alternately stacked in multiple layers is used on the outer surface of the glass bulb. However, there is a problem that an additional member is required and the cost increase cannot be avoided.

  As a specific means for solving the above-described conventional problems, the present invention provides a fluorescent tube in which mercury and an inert gas having a predetermined sealing pressure are sealed in a glass tube valve in which electrodes are arranged to face each other. In the lamp, the inert gas is composed of argon and neon, krypton or xenon, and the initial mixing amount of the krypton or xenon in the inert gas is 2 to 10%, In addition, by providing a liquid crystal backlight device that employs the fluorescent lamp as a light source, it is possible to provide a fluorescent lamp that does not emit near-infrared light even at startup, thereby solving the problem.

  According to the present invention, by mixing an appropriate amount of krypton or xenon gas in addition to argon and neon as the inert gas sealed in the glass tube bulb of the discharge lamp, the main part of the gas discharge at start-up is from argon. By moving to krypton, infrared radiation near 910 nm and 920 nm can be greatly reduced. Therefore, the glass tube bulb does not particularly need to suppress near-infrared radiation, and costs can be reduced.

  Next, the present invention will be described in detail based on the embodiments shown in the drawings. The curve indicated by the symbol R in FIG. 1 is an example of a radiation spectrum when the infrared remote controller is operated. For example, the intensity difference varies depending on the type of the modulation code, such as for channel switching of a television receiver or for power on / off. Is generated, but is basically light from the same LED, and the spectral distribution is the same.

  Therefore, for example, a light receiving element (not shown) attached to a household electrical appliance such as an air conditioner is naturally adopted to have sensitivity to the wavelength in the range shown in FIG. It is done. In recent years, home appliances operated by an infrared remote controller such as a video tape recorder and a DVD recorder tend to increase, and it is a general phenomenon that a plurality of infrared remote control receivers exist in one room. .

  Another trend is the trend of large-screen, thin television receivers that employ liquid crystal display elements. Here, since the liquid crystal display element does not have a self-luminous function, a backlight device is used, and most of the liquid crystal display elements perform transmission illumination with a fluorescent lamp (cold cathode fluorescent lamp) from the back side of the liquid crystal display element. is there.

  As described above, the problem that has become apparent under the above-described conditions is that the amount of mercury vapor in the fluorescent lamp is relatively small at the time of lighting, and when the backlight device is turned on in this state, When the lamp is turned on, it is started with a buffer gas such as argon gas, and when the fluorescent lamp is started, infrared light in the vicinity of 910 to 920 nm is emitted from the fluorescent lamp.

  The curve indicated by the symbol AL in FIG. 2 is an example of a radiation spectrum when starting with argon gas as described above, and typically outputs are generated in the vicinity of 850 nm, 910 nm, and 920 nm. Therefore, the outputs near 910 nm and 920 nm are received by the light receiving unit of the infrared remote controller.

  Here, for example, when there are a plurality of the fluorescent lamps and a time difference is generated when each of them starts, the light receiving unit of the remote controller has something similar to the command and code set inside The operation is started with respect to home appliances or the like, that is, a malfunction occurs.

  Further, for example, when the power of the LCD TV is turned on while operating other household appliances such as an air conditioner with the infrared remote controller, the light receiving unit on the air conditioner side has near ultraviolet rays from the infrared remote controller for the air conditioner and the fluorescent lamp. The near-infrared light emitted (see FIG. 1) is received redundantly, and part of the code transmitted by the infrared remote control is masked, etc., so that the air conditioner cannot operate or does not perform a predetermined operation. It will be a thing.

  Here, the inventor studied the sealed gas in order to develop a fluorescent lamp that generates less infrared light even at the start-up in order to solve the malfunction and malfunction of the infrared remote control. The composition which adds krypton gas newly to the combination of argon gas and neon gas was found.

  That is, infrared light near 910 nm and 920 nm, which causes the infrared remote controller to malfunction, is radiated by argon gas. By adding krypton gas to the sealed gas, the energy of the above infrared wavelength can be greatly reduced. The inventor confirmed. This is because the ionization voltage of the krypton gas is lower than that of the argon gas. By mixing the krypton gas, the main part of the gas discharge at the start-up shifts from the argon gas to the krypton gas, and the infrared light near 910 nm and 920 nm is greatly increased. I think that it decreased.

  The amount of krypton gas mixed for obtaining the above effect will be considered below. With the addition of krypton gas, based on the amount of infrared radiation when the fluorescent lamp (hereinafter referred to as the conventional lamp) that is not mixed with conventional krypton gas and argon gas and neon gas only added to mercury is always lit, When 0.5% is added, as shown by a curve R in FIG. 3, the amount of infrared radiation can be made equal to or less than that of a conventional lamp even at the start. Therefore, in the present invention, the minimum addition amount of the krypton gas is set to 0.5%.

  However, as the mixing amount of krypton gas is increased, the amount of infrared radiation near 910 nm and 920 nm, which is the most effective in preventing the malfunction of the infrared remote controller, is further reduced. However, as shown in FIG. In addition, the infrared light near 880 nm and 890 nm generated by the discharge of krypton gas tends to increase, and this time, the infrared light in this range may cause a problem.

  In addition, since the presence of krypton gas inhibits the Penning effect between argon gas and mercury, the starting voltage of the fluorescent lamp to which krypton gas is added is higher than that of the conventional lamp as shown in FIG. From this point as well, it is preferable to keep the amount of krypton gas added within a range in which a conventional lamp lighting device can be used.

  From the above viewpoint, in the present invention, there is no significant increase in the amount of infrared light emitted near 880 nm and 890 nm, and the starting voltage is about 10% of the starting voltage of the conventional lamp. An addition amount of 10% that can be accommodated by the rise was set as the maximum value of the krypton gas addition amount. Therefore, in the present invention, the amount of krypton gas added is set in the range of 0.5 to 10%.

  Next, the inventor made a test of the fluorescent lamp of the present invention in which the amount of the krypton gas added was set in the range of 0.5 to 10%, and tested it to evaluate the practicality. As a standard for evaluation, 0.5% or more of krypton gas remains after the life required for this type of fluorescent lamp used as a light source of a liquid crystal television, and after lighting for 60000 hours. Judgment was made by not affecting the infrared remote control described as a problem.

  Note that the change in the amount of krypton gas or the like due to lighting is taken into the scattered material by sputtering of the electrode being lit and physically adsorbed on the inner wall of the lamp tube. Or, it is a phenomenon that decreases gradually due to being ionized and colliding with the electrode when it collides with the electrode.

  The sputtering differs depending on the shape of the glass bulb, and tends to depend particularly on the inner diameter. Therefore, a prototype was formed and tested according to the shape used for the light source of the liquid crystal television, which is the main application of this type of fluorescent lamp.

  As shown in FIG. 5, a phosphor layer 2a is formed on the inner surface of a glass bulb 2 having an outer diameter = 3 mm, an inner diameter = 2 mm, and a length = 730 mm, electrodes 3 are arranged at both ends, mercury 4 is contained inside, The fluorescent gas 1 was produced by sealing the buffer gas having the structure of 60 at a pressure of 60 torr.

  Structure of enclosed gas Argon gas (5): Neon gas (6): Krypton gas (7) = 5: 93: 2 (partial pressure ratio)

  FIG. 6 shows changes over time in the luminance change rate Br and the krypton gas Kr remaining amount when the fluorescent lamp 1 is continuously turned on. Even when the luminance is halved (lifetime), the remaining amount of krypton gas is maintained at 0.5%. As a result of this experiment, if the initial mixing amount of krypton gas is 2% or more, 0.5% or more of krypton gas remaining in the luminance half-life can be secured in a fluorescent lamp having an inner diameter of 1.6 mm to 6 mm and a total length of 500 to 1500 mm. Was confirmed. The experiment was conducted with a cold cathode fluorescent lamp, but this measure is also effective for a hot cathode fluorescent lamp.

  By mixing krypton gas in addition to the conventional argon gas and neon gas into the buffer gas of the fluorescent lamp, it is possible to reduce the infrared light around 910 nm that is radiated remarkably when starting in a low temperature atmosphere. As a result, it is possible to eliminate problems and claims that the infrared remote controller malfunctions when the liquid crystal display is started.

  And since conventional infrared radiation countermeasures are made by adding an infrared blocking substance etc. to the outside of the lamp (glass bulb), there has been a problem that the number of parts and processes increase and the cost increases. According to the present invention, since a very small amount of krypton gas is added to the sealed gas of the lamp, there is no substantial increase in cost.

  Further, in the present invention, since the amount of addition is defined in consideration of the consumption of krypton gas generated during use, the effect of the invention is reliably maintained from the beginning of the life of the fluorescent lamp to the end of the life. .

It is a graph which shows the output wavelength spectrum of an infrared remote control. It is a graph which shows the infrared component radiated | emitted at the time of the starting of a fluorescent lamp. It is a graph which shows an infrared component when krypton gas is added to buffer gas. It is a graph which shows the relationship between the addition amount of krypton gas, and a starting voltage. It is explanatory drawing which shows typically the structure of the fluorescent lamp which concerns on this invention. It is a graph which shows the relationship between the lighting time of a fluorescent lamp, and the residual amount of krypton gas.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fluorescent lamp 2 ... Glass bulb 2a ... Phosphor 3 ... Electrode 4 ... Mercury 5 ... Argon gas 6 ... Neon gas 7 ... Krypton gas

Claims (2)

  In a fluorescent lamp in which mercury and an inert gas having a predetermined sealing pressure are sealed in a glass tube bulb having electrodes opposed to each other, the inert gas is composed of argon and neon and krypton or xenon. The fluorescent lamp is characterized in that an initial mixing amount of the krypton or the xenon in the inert gas is 2 to 10%.   2. A liquid crystal backlight device employing the fluorescent lamp according to claim 1 as a light source.

Images