KR100945864B1 - Glass for backlight lamps - Google Patents

Abstract

The present invention is a glass for backlight lamp, the oxide reduction by SiO ₂ 65 ~ 75wt%, B ₂ O ₃ 16 ~ 19wt%, P ₂ O ₅ 0.1 ~ 0.8wt%, BaO 0.5 ~ 3.0wt%, SrO 0.1 ~ 5wt %, CaO 0 ~ 3wt%, MgO 0 ~ 3wt%, CeO ₂ 0.005 ~ 1wt%, Fe ₂ O ₃ 0.005 ~ 1wt%, TiO ₂ 0.005 ~ 1.5wt%, Al ₂ O ₃ 0.5 ~ 5wt%, Li ₂ O 0-5wt%, Na ₂ O 4-6wt%, K ₂ O 2.5-4.0wt%, Sb ₂ O ₃ 0-1wt%, TiO ₂ + P ₂ O ₅ is limited to 2wt% or less It is related with the glass for backlight lamps characterized by the thing.

Description

Glass for backlight lamps {Glass for a backlighting lamp}

The present invention relates to a glass used in the manufacture of a cold cathode fluorescent lamp backlight, basically having a thermal expansion coefficient of 48 ~ 54x10-7 / ℃ and UV protection characteristics and solarization protection of less than 340nm and at the same time minimize the dielectric loss energy The efficiency of the lamp is maximized.

Recently, the growth of LCD in the display industry is remarkable. LCD is an abbreviation of Liquid Crystal Display. It is a display that uses a change in the transparency of liquid crystal display. It has no self-illumination and requires backlighting, but it is a kind of flat panel display which consumes less power and is convenient for mobile. Backlight lamps emit light through various polarizing films and optical films. The most important of these is the backlight lamp.

The use of LCD has been expanded to almost replace the existing display field, and at the same time, it is required to be lighter, thinner, lower in cost, and higher in brightness. Miniaturization and high efficiency are required.

Cold cathode fluorescent lamps are mainly used as backlight lamps, and the characteristics of the glass used are basically required to have high heat resistance, mechanical strength, UV protection, solarization prevention, and the like.

Against this background, fluorescent lamps using borosilicate glass have been developed and commercialized. KOVAR alloys are mainly used as electrodes of cold cathode fluorescent lamps.

In order to maximize the luminous efficiency, high voltage and high frequency are used for low expansion borosilicate glass used in backlight fluorescent lamps according to the demand for high brightness and low power consumption of LCD. Under these circumstances, in order to maximize the efficiency of the lamp and minimize the heat of the electrode, a composition development that minimizes the dielectric loss energy of the glass itself is required.

An object of the present invention is to provide a glass for backlighting that minimizes the dielectric loss energy.

On the other hand, an object of the present invention is to provide a glass for backlighting that can prevent the stability and solarization of the ultraviolet absorption stage.

The present invention is a glass for backlight lamp, the oxide reduction by SiO ₂ 65 ~ 75wt%, B ₂ O ₃ 16 ~ 19wt%, P ₂ O ₅ 0.1 ~ 0.8wt%, BaO 0.5 ~ 3.0wt%, SrO 0.1 ~ 5wt %, CaO 0 ~ 3wt%, MgO 0 ~ 3wt%, CeO ₂ 0.005 ~ 1wt%, Fe ₂ O ₃ 0.005 ~ 1wt%, TiO ₂ 0.005 ~ 1.5wt%, Al ₂ O ₃ 0.5 ~ 5wt%, Li ₂ O 0-5wt%, Na ₂ O 4-6wt%, K ₂ O 2.5-4.0wt%, Sb ₂ O ₃ 0-1wt%, TiO ₂ + P ₂ O ₅ is limited to 2wt% or less It is related with the glass for backlight lamps characterized by the thing.

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In the case of the present invention to solve the problems of the prior art to minimize the dielectric loss energy of the glass, to maximize the efficiency of the lamp in the situation of using a high voltage and high frequency, it has the effect of minimizing the heat of the electrode portion.

On the other hand, the present invention has the effect of preventing the stability and solarization of the ultraviolet absorption stage.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

When alternating current flows through glass, glass absorbs alternating energy and is released as heat. The dielectric loss energy converted from the lamp to the final heat is proportional to the dielectric constant and dielectric loss (tanδ) determined by the structure and composition of the glass, as shown in the equation below.

W = kfv ² ε tan δ

Where W is the dielectric loss energy, k is the constant, f is the operating frequency of the lamp, v is the voltage of the lamp, ε is the dielectric constant, and tanδ is the dielectric loss.

In order to minimize the dielectric loss energy, the glass tube for the lamp of the present invention minimizes the dielectric constant by using a large amount of SiO ₂ + B ₂ O ₃ and using a small amount of TiO ₂ component having a high dielectric constant, and simultaneously, P ₂ O ₅ 0.005 Dielectric losses were also minimized by using ~ 2wt%, BaO 0.1-5wt%, SrO 0.1-5wt%, CaO 0-5wt%.

In addition, a plastic light guide plate and a diffusion plate are used to increase the brightness of the backlight unit. Due to the characteristics of the lamp, the ultraviolet ray deterioration wavelength is around 330 nm, so the glass itself basically has the characteristics of UV protection and anti-solarization of less than 340 nm. Should be equipped with. In order to have such UV blocking and anti-solarization characteristics, a method of containing a large amount of TiO ₂ is mainly used as in the comparative example of the table shown in FIG. 1. However, as the amount of TiO ₂ added increases, the phase separation tendency of the borosilicate glass solution tends to be strong, and at the same time, the crystallization phenomenon mainly due to TiO ₂ is likely to occur. high.

The combination of CeO ₂ , Fe ₂ O ₃ and the like also shows UV blocking characteristics of 340 nm or less, but the UV absorption stage is not stable, and the discoloration of the glass due to ultraviolet rays (253.7 nm) emitted from the lamp itself, that is, solarization phenomenon Is likely to occur.

In the present invention, as a result of various studies, CeO ₂ + Fe ₂ O ₃ having UV blocking properties is basically used, and at the same time, a small amount of P ₂ O ₅ + TiO ₂ is used to prevent the stability and solarization of the ultraviolet absorption stage. Could.

In addition, when used as a fluorescent lamp having an internal electrode, the coefficient of thermal expansion should be a value suitable for the expansion of the electrode material. The coefficient of thermal expansion of glass having this composition is located at 48 ~ 54 × 10 ^-7 / ℃, currently mainly used Kovar metals and seals are suitable.

Implement the invention  Best form for

The present invention achieves the above object and describes the role and content of the glass component used in the present invention.

SiO ₂ is an essential component for forming the skeleton of the glass, and as the content thereof increases, the electrical insulating property increases, and the dielectric constant factor is present between 3.5 and 3.6. The dielectric loss is also lower as the content increases, and the increase in dielectric loss with increasing temperature is also very small. In the present invention should contain about 65 ~ 75wt% of SiO _2. It is desirable to maintain the content of 68% or more.

In the present invention, the B ₂ O ₃ is contained in an amount of about 10 to 20 wt%, and thus has the characteristics of borosilicate glass. B ₂ O ₃ is a necessary ingredient for adjusting the coefficient of thermal expansion and improving meltability, and does not lower the electrical resistance or increase the dielectric loss. The dielectric constant is 5.4 to 5.6, the _second lowest after SiO ₂ . The content is preferably 20% or less in consideration of volatilization and the like during the melting process.

In the present invention, Al ₂ O _{3 It} contains 0.5 ~ 5wt%, Al ₂ O ₃ restrains alkali that did not participate in the bond in the glass serves to strengthen the structure of the glass and increase the viscosity characteristics of the glass, The modulus of elasticity is also nearly two times higher than that of SiO ₂ . In particular, when the P ₂ O ₅ component is used in glass, whitening occurs due to powder phase. At this time, if Al ₂ O ₃ is used, the whitening is strongly reduced. However, the permittivity factor is somewhat large, such as 9.0 to 9.2, and there is almost no effect of lowering the dielectric loss, and the content thereof is preferably 0.5 wt% or more and 5 wt% or less.

In the present invention, the P ₂ O ₅ is contained in an amount of about 0.005 to 1.5 wt%, preferably about 0.1 to 0.8 wt%. P ₂ O ₅ acts as a network forming agent for glass similar to SiO ₂ , B ₂ O _3, etc., but has a property of crystallizing in most mixed regions in a SiO ₂ -P ₂ O ₅ system. In the present invention, the amount of less than 1.5wt% was used for improving the meltability and lowering the dielectric loss while preventing the milky white. When the P ₂ O ₅ component is more than 1.5wt%, the color of the glass changes to milky white.

In the present invention, BaO is contained in an amount of about 0.1 to 5 wt%, preferably about 0.5 to 3.0 wt%. BaO, similar to PbO, increases the elastic modulus of glass, increases electrical insulation, and serves to reduce dielectric loss. do. However, when used a lot, the dielectric constant is rather increased, so the use content is preferably limited to 5wt% or less. SrO, which serves to improve frictional resistance, also exhibits electrical characteristics similar to BaO, and its amount is preferably not more than 5 wt%.

CaO not only plays a role in strengthening the glass structure but also has a significant effect on lowering the dielectric loss. Its usage is limited to 3wt% or less because of its softening point. In addition, MgO is a component that lowers the dielectric constant and dielectric loss at the same time, it is preferable to limit the use to 3wt% or less.

The present invention contains about 0.005 to 1wt% of CeO ₂ , preferably about 0.05 to 0.3wt%. CeO ₂ has been used for ultraviolet blocking property in combination as 0.005 ~ 1wt% of a trace amount of Fe ₂ O ₃ of preferably approximately 0.005 ~ 0.1wt% trace amount of Fe ₂ O ₃ were such that the UV light of 340nm or less cut off.

The present invention contains about 0.005 to 1.5 wt% of TiO ₂ , preferably about 0.05 to 0.3 wt%. A small amount of TiO ₂ + P ₂ O _{5 was} used to minimize solarization of the glass by UV and to stabilize the UV absorption end. The present invention contains TiO ₂ + P ₂ O ₅ 0.01 ~ 2wt%, the use of TiO ₂ + P ₂ O ₅ components are limited to less than 2wt%, the TiO ₂ components are limited to 1.5wt% or less It is preferable to use. If more than that is used, the visible light transmittance is lowered.

Meanwhile, the present invention contains Li ₂ O about 0 to 5 wt%, Na ₂ O about 0.1 to 10 wt%, K ₂ O about 0.1 to 10 wt%, and Sb ₂ O ₃ about 0 to 1 wt%. . Sb ₂ O ₃ The UV transmittance is reduced to provide an ultraviolet blocking effect.

As a result of the measurement by this method, the results as shown in FIGS. 1 and 2 were obtained. In order to perform a comparative experiment, as shown in FIG. 1, various borosilicate glasses produced at present were obtained and compared with the changed composition.

The specimens used to measure the dielectric constant and dielectric loss were polished on both sides with a thickness of 1 mm, a width of 10 mm, and a length of 10 mm, and their characteristics were compared at 1 MHz at room temperature with a precision LCR meter (HP model).

UV cut properties, namely UV cut (nm) was used by using a UV-Visible-NIR spectrometer (Perkin Elmer, Lambda9), the thickness of the specimen was measured by double-sided polishing to 2 mm.

Solarization was performed by using a 400W high-pressure mercury lamp in which 253.7 nm of ultraviolet rays were generated on an optically polished 2 mm glass, and irradiated with ultraviolet rays for 300 hours, and then compared with an initial transmittance. First, the transmittance T _i of wavelength 450 nm was measured before irradiation of the specimen and the transmittance ratio (%) of solarization was measured by measuring the transmittance Ta of 450 nm after ultraviolet irradiation of the same specimen.

Permeability ratio by solarization (%) = (T _i -Ta) * 100 / T _i

According to the above test results, all the samples of "Comparative Example" have large dielectric loss. In addition, the sample of "Example" also showed a better UV blocking effect.

As can be seen from the above characteristic observation, the glass having the composition as the present invention has a significantly smaller dielectric loss than the conventional borosilicate glass, and nevertheless, UV protection or solarization characteristics are not bad and have better characteristics.

The embodiments of the present invention described above are examples of one of the embodiments of the present invention, and the present invention is not limited thereto, and the present invention includes equivalents and equivalents thereof.

1 and 2 are characteristic data for comparing and explaining the characteristics of the embodiments of the present invention with comparative examples.

Claims (3)

In the glass for a backlight lamp, SiO ₂ 65 ~ 75wt%, B ₂ O ₃ 16 ~ 19wt%, P ₂ O ₅ 0.1 ~ 0.8wt%, BaO 0.5 ~ 3.0wt%, SrO 0.1 ~ 5wt%, CaO 0 ~ 3wt%, MgO 0 ~ 3wt%, CeO ₂ 0.005 ~ 1wt%, Fe ₂ O ₃ 0.005 ~ 1wt%, TiO ₂ 0.005 ~ 1.5wt%, Al ₂ O ₃ 0.5-5wt%, Li ₂ O 0-5wt%, Na ₂ O 4 ~ 6wt%, K ₂ O 2.5 ~ 4.0wt%, Sb ₂ O ₃ 0 ~ 1wt%, TiO ₂ + P ₂ O _{5 It} is characterized in that it is limited to less than 2wt% Glass for backlight lamps delete The method of claim 1, It is characterized by containing 0.05 ~ 0.3wt% of CeO ₂ and 0.005 ~ 0.1wt% of Fe ₂ O ₃ by oxide reduction. Glass for backlight lamps

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