JP2006321689A - Crystallized glass composite body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystallized glass composite body which can obtain a white color by a single exciting light source and can be used as a fluorescent material for a miniaturized white color light source having an excellent color rendering. <P>SOLUTION: This crystallized glass composite body comprises Er-based crystallized glass which contains Er ions as light emitting ions and in which CaF<SB>2</SB>is deposited as a crystal phase and Tm-based crystallized glass which contains Tm ions as light emitting ions and in which CaF<SB>2</SB>is deposited as a crystal phase, and is excited by near infrared light and emits white color light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a crystallized glass composite.

  Conventionally, fluorescent lamps, halogen lamps, incandescent lamps and the like have been mainly used as white light sources. In recent years, with the expansion of the liquid crystal display (LCD) market represented by mobile phones and personal computers, the need for small white light sources as backlights for LCDs has increased, and white LEDs have been used for this purpose. . In general, a white LED is mainly used in which a phosphor that emits yellow fluorescence by blue excitation light is disposed on an excitation light source, and white is obtained by mixing yellow fluorescence and blue excitation light that passes through the phosphor. This method is suitable for obtaining a small white light source. However, since the spectrum constituting white is composed of blue and yellow, there is a drawback that the color reproducibility under natural light, so-called color rendering, is poor. As another method, there is one in which LEDs emitting three primary colors of red, blue, and green are integrally arranged to obtain white, but this method is not suitable for downsizing.

  On the other hand, as a method other than using an LED, a method of obtaining white by mixing fluorescent light emitted from various fluorescent materials is conceivable. However, since the excitation wavelengths of various phosphors are often different from each other, a plurality of excitation light sources are required, and furthermore, since the excitation wavelengths of many phosphors overlap with the visible light region, There is a drawback that the color rendering of white light is lowered. Accordingly, it has been desired to develop a fluorescent material capable of obtaining white color with a single excitation light source and having good color rendering properties.

An example of a material that emits light having a wavelength different from the excitation wavelength is an up-conversion material. Fluoride-based ceramic materials containing Yb ³⁺ and Er ³⁺ are known as this up-conversion material, but these materials are opaque and it is difficult to obtain white light because of the visible light absorption of the material. is there. On the other hand, a transparent crystallized glass containing Yb ³⁺ and Er ³⁺ and precipitating PbF ₂ crystals is known as an up-conversion material that hardly absorbs visible light (see, for example, Patent Document 1). ).
JP-A-7-69673

However, as described in Patent Document 1, Yb ³⁺ -Er ^{3 +} -containing PbF ₂ -based crystallized glass has an emission wavelength of 550 nm (green) and 660 nm (red), so the emission color is yellowish green. In addition, a white color with good color rendering properties cannot be obtained, and further, since Pb, which is an environmental load substance, is contained, there is an environmental problem.

  The present invention has been made in view of the above circumstances, and provides a crystallized glass composite that can be used for a fluorescent material for a small white light source that can obtain white color with a single excitation light source and has good color rendering properties. The purpose is to do.

  The present inventors have conceived that near-infrared rays having extremely low visibility are used as an excitation light source in order to prevent a decrease in color rendering due to excess excitation light. In other words, the application of so-called up-conversion, which uses visible light that is invisible to the human eye and emits visible light with a shorter wavelength, affects the color rendering even when there is excess excitation light. This is because I thought it was possible to avoid.

The present inventors have made SiO ₂ —Al ₂ O ₃ —CaO—CaF ₂ —YbF ₃ —ErF ₃ system (hereinafter referred to as Er system) and SiO ₂ —Al ₂ O ₃ —CaO—CaF ₂ —YbF ₃ —. By mixing TmF ₃ glass (hereinafter referred to as Tm glass) with heat treatment and compounding at least two kinds of crystallized glass on which CaF ₂ crystals are precipitated, it is possible to mix the three primary colors by near-infrared light excitation. It is found that white light can be obtained, and is proposed as the present invention.

That is, the crystallized glass composite of the present invention includes an Er-based crystallized glass containing Er ions as luminescent ions and precipitating CaF ₂ as a crystal phase, and Tm ions as luminescent ions and precipitating CaF ₂ as a crystal phase. And Tm-based crystallized glass, which emits white light when excited by near-infrared light.

  According to such a configuration, it is possible to obtain white color with a single excitation light source, and since there is no deterioration in color rendering due to excess excitation light, a fluorescent material suitable for a small white light source is provided. Is possible. Further, a light emitting diode having a wavelength of 920 to 1000 nm, which is often used in the optical communication field, can be used as an excitation light source, and a white light source can be produced with an inexpensive configuration.

That is, in the Er-based crystallized glass, the excitation light having a wavelength of 920 to 1000 nm,
⁴ S _3/2 - ⁴ fluorescence and ⁴ F of 550nm (green) by the transition between the I _15/2 level _9/2 - ⁴ I _15/2 fluorescence of 660nm (red) by the transition between levels occurs. In Tm-based crystallized glass,
¹ G ₄ - ³ fluorescence H ₆ 480 nm by transition between levels (blue) is generated. Moreover, although these crystallized glasses have a large absorption effect on the excitation light, they are small in the mutual fluorescence, and even if they are combined, the mutual light emission efficiency is maintained. A white color with high color rendering properties can be obtained by appropriately controlling the diameter and the irradiation direction of the excitation light. Since the excitation light is near-infrared light, even if the excitation light is excessively irradiated, the color rendering does not deteriorate, it is possible to sufficiently irradiate the excitation light, and high fluorescence intensity can be obtained. It is. In addition, upconversion efficiency can be greatly improved by allowing Yb ions to coexist with Er ions and Tm ions.

  As described above, according to the present invention, it is possible to obtain white color with a single excitation light source, and since there is no deterioration in color rendering due to excess excitation light, it is suitable for a small white light source. It is possible to provide a crystallized glass composite that can be used as a material. In addition, since it does not contain an environmental load substance and a light emitting diode having a wavelength of 920 to 1000 nm used in the optical communication field can be used as an excitation light source, it is possible to obtain a white light source with an inexpensive configuration. It greatly contributes to the development of a new small white light source.

In the crystallized glass complex of the present invention, at least one of the Er-based crystallized glass and Tm-based crystallized glass, SiO ₂ 20~60mol%, 0~30mol% of _Al 2 _{O 3,} a CaF _2. 10 to It is preferable to contain 40 mol% and CaO 0-20 mol%.

  In the crystallized glass composite of the present invention, the Er-based crystallized glass preferably has an Er ion content of 0.1 to 3.0 mol% and a Yb ion content of 0 to 15 mol%. The Tm-based crystallized glass preferably has a Tm ion content of 0.05 to 0.5 mol% and a Yb ion content of 0.3 to 10 mol%.

  In the crystallized glass composite of the present invention, it is preferable that the Er-based crystallized glass and the Tm-based crystallized glass have a mass ratio of 1:10 to 10: 1.

  As a method for compounding crystallized glass in the present invention, there are a method of laminating plate-like crystallized glass and a method of integrating powdered crystallized glass.

  In the former, in addition to the method of fusing crystallized glasses together, it is possible to combine them with an adhesive such as resin or glass. In this way, the RGB light emission intensity ratio does not depend on the laser beam irradiation position.

  In the latter case, the crystallized glass powder can be sintered, or the crystallized glass powder before crystallization can be heat treated to simultaneously perform crystallization and sintering. Further, the crystallized glass powder may be mixed with glass or resin that is inert to the excitation light to be compounded. As long as the effects of the present invention are not adversely affected, other types of crystallized glass or upconversion materials other than crystallized glass can be mixed.

  Examples of the present invention will be described below.

A glass having a composition of _{45SiO 2 -20Al 2 O 3 -10CaO-} 22CaF 2 -2YbF 3 -1ErF 3 molar _ratio, the composition of _{45SiO 2 -20Al 2 O 3 -10CaO-} 20CaF 2 -5YbF 3 -0.05TmF 3 Each glass having a melting point was melted at 1300 ° C. in air using a platinum crucible. Next, both glasses were subjected to heat treatment at 700 to 750 ° C. for 4 hours to obtain Er-based and Tm-based transparent crystallized glasses on which CaF ₂ crystals were precipitated. The fluorescence spectrum was measured using an InGaAs semiconductor laser beam having a wavelength of 970 nm as an excitation light source, and the emission spectrum was confirmed by a fiber multichannel spectrometer (USB2000, Ocean Optics).

  FIG. 1 shows the emission spectrum of Er-based glass and FIG. 2 shows the emission spectrum of Tm-based crystallized glass. It can be seen that green and red fluorescence can be obtained from the Er system, and blue and red fluorescence can be obtained from the Tm system.

  In FIG. 3, a crystallized glass composite obtained by laminating both crystallized glasses polished to a thickness of 1 mm with an organic adhesive is irradiated with excitation light (InGaAs semiconductor laser light having a wavelength of 970 nm) from an incident angle of 90 °. The results of measuring the emission spectrum are shown. It can be seen that the fluorescence of the three primary colors is obtained simultaneously. The emission spectrum has higher fluorescence intensity in the order of emission bands with lower specific visibility. As a result, as shown in the chromaticity coordinates of FIG. (X, y) = (0.33, 0.33), black square mark). In addition, by changing the incident angle of the excitation light to the crystallized glass composite, the emission intensity of each emission band can be changed, and the chromaticity of the obtained white light can be controlled.

The emission spectrum of Er type | system | group crystallized glass is shown. The emission spectrum of Tm type | system | group crystallized glass is shown. The emission spectrum of the crystallized glass composite of the present invention is shown. The color coordinate of the emission spectrum of the crystallized glass composite of the present invention is shown.

Claims (5)

And Er-based crystallized glass CaF ₂ was precipitated as containing crystallized phases Er ions as luminescent ions, it contains Tm ions as luminescent ions containing the Tm-based crystallized glass CaF ₂ was precipitated as a crystal phase, near A crystallized glass composite which is excited by infrared light and emits white light. 2. The crystallized glass composite according to claim 1, wherein the Er-based crystallized glass plate and the Tm-based crystallized glass plate are combined in layers. The crystallized glass composite according to claim 1, wherein a powder body containing an Er-based crystallized glass powder and a Tm-based crystallized glass powder is sintered and compounded. 2. The crystallization according to claim 1, wherein the powder body containing Er-based crystallized glass powder and Tm-based crystallized glass powder is compounded with glass or resin that is inert to excitation light. Glass composite. The crystallized glass composite according to any one of claims 1 to 4, wherein the Er-based crystallized glass and the Tm-based crystallized glass contain Yb ions.

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