JPH0954562A - Transparent wavelength conversion type light emitting panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light emitting panel useful for a display, etc., by forming a wavelength conversion material of an up conversion type as a panel. SOLUTION: This panel is composed of a three-layered sandwich structure of a transparent plate/phosphor/transparent plate formed by holding the sheet of a transparent glassy phosphor of the up-conversion type for converting an IR or red laser beam to visible light of a low wavelength between two transparent plates. The production of the panel is executed by first molding the transparent glassy phosphor to a sheet form by a technique similar to the technique of producing sheet glass. Since the transparent glassy phosphor formed in such a manner is usually thin in thickness, the phosphor is structurally weak and is poor in moisture resistance and, therefore, the strength and durability are insufficient with this sheet alone. The sandwich structure to insert the transparent glassy phosphor between the two transparent sheets or films is adopted in order to impart the sufficient strength and durability to the sheet. The IR laser beam is converted to the visible light of the low wavelength if the transparent panel is irradiated with this IR laser beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent wavelength conversion type light emitting panel capable of converting infrared or red laser light into visible light having a lower wavelength. Since the light-emitting panel of the present invention is transparent, when it is not irradiated with infrared light or red light, it is the panel itself, and when it is irradiated with infrared light or red light, it emits light of low wavelength (example , Green light), various displays can be performed, and for example, it can be used for window glass, partition, etc. for illumination or display.

[0002]

2. Description of the Related Art Converting infrared or red laser light into visible light of lower wavelength (that is, higher energy),
As a so-called up-conversion type wavelength conversion material (phosphor), for example, a YLiF ₄ crystal doped with Tm ³⁺ is known. When it is irradiated with infrared laser light, it converts infrared light into blue light and emits it.

Further, Japanese Patent Application Laid-Open No. 7-62334 of the present applicant
The publication discloses that a luminescent source material composed of an erbium (Er) halide and a luminescence assisting material composed of a gadolinium (Gd) or lanthanum (La) halide do not require pre-excitation and have a light conversion efficiency. A large up-conversion type illuminant has been proposed.

However, since most of the conventional up-conversion type phosphors are crystalline, it is difficult to mold them into an arbitrary shape, and transparency cannot be obtained. In order to expand the applications of wavelength conversion materials, amorphous, that is, glassy phosphors are required, but as glassy upconversion type phosphors, fluorescent glass obtained by doping Ho ³⁺ into fluoride glass is used. The body is only known so far (Japanese Patent Laid-Open No. 6-219777). However, this phosphor has a low wavelength conversion rate (emission luminance) and cannot obtain high luminance, and thus is not practical.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting panel which is useful as a display or illumination by using an up-conversion type wavelength conversion material and converting it into a panel.

[0006] Specifically, an object of the present invention is to provide a light-emitting panel which has a high emission brightness, can be easily processed, and uses a transparent wavelength conversion material of an up-conversion type and has excellent durability. .

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have added an alkaline earth metal chloride as a glass forming aid to the up-conversion type luminescent material described in JP-A-7-62334. It was previously proposed that a transparent vitreous wavelength conversion material (phosphor) which can be easily vitrified and has high emission brightness can be obtained by doing so (Japanese Patent Application Nos. 6-95477 and 6-83447). , 6-219405, 6
-219406). This phosphor is capable of converting infrared or red laser light into lower wavelength visible light.

As a result of subsequent research, a panel having a sandwich structure is formed by molding such a phosphor having a high emission brightness into a glass sheet in the same manner as in the production of plate glass, and sandwiching the glass sheet between two transparent plates. It was found that the above-mentioned object can be achieved by producing the present invention, and the present invention was completed.

Here, the present invention has a structure in which a sheet of transparent glassy phosphor for converting infrared or red laser light into visible light of a lower wavelength is sandwiched between two transparent bodies. It is a wavelength conversion type light emitting panel.

This glassy phosphor sheet is a material containing a Gd halide as a main component of a glass base material, an alkaline earth metal chloride as a glass forming aid, and a rare earth halide as an emission center. Can be made from.

Hereinafter, the present invention will be described in detail. The wavelength conversion type light-emitting panel of the present invention is a transparent glass sheet of up-conversion type, which converts infrared or red laser light into visible light of lower wavelength, is sandwiched between two transparent plates. It is composed of a three-layer sandwich structure of plate / phosphor / transparent plate. The light emitting panel of the present invention is transparent as a whole, and has excellent durability due to the above three-layer structure. When this transparent panel is irradiated with infrared laser light or red laser light, it is converted into visible light of a lower wavelength and the irradiation part emits light.

The wavelength conversion material used in the present invention (ie,
In addition to the requirement that the fluorescent substance is a transparent glass, it is desirable that it has no pre-excitation, has a fast wavelength conversion response speed, and has high brightness, and that it has good processability.

An example of a phosphor satisfying the above conditions is that the halide of Gd is the main component of the glass base material, the chloride of the alkaline earth metal is the glass forming aid, and the halide of the rare earth is the luminescence center. It is a glassy phosphor that does.

Specifically, among the constituents of the phosphor, the halide of Gd which is the main component of the glass base material is Gd.
1 to 2 or more selected from chloride, fluoride, iodide and bromide of 40 to 90 mol% of the phosphor
To be present. The alkaline earth metal chloride, which is a glass forming aid, is one or two selected from BaCl ₂ , SrCl ₂ and CaCl _2, and ₁₀ to 45 mol% of the phosphor.
To be present. The rare earth halide serving as the emission center is one or more selected from chlorides, fluorides, iodides and bromides of rare earth metals such as lanthanum Nd, Ho, Er, Tm and Yb. Is preferred, which is an amount of 0.05 to 30 mol% of the phosphor.

A preferred phosphor is 40 to 90 mol% of GdCl ₃ as a main component of the glass base material, more preferably 50 to 70 mol%, and BaCl ₂ , SrCl ₂ , CaCl ₂ and BaCl ₂ as glass forming aids.
+ SrCl ₂ , BaCl ₂ + CaCl ₂ , or SrCl ₂ + CaCl ₂ 10-45 mol%, more preferably contains 15-30 mol%, further ErCl ₃ , TmCl ₃ , HoCl ₃ , as a luminescent center. One of NdCl ₃
The content is 0.05 to 20 mol%, more preferably 0.5 to 5 mol%. If necessary, YbCl ₃ may be added as a sensitizer, and in this case, the total amount of the sensitizer YbCl ₃ and the above-mentioned luminescent center is 0.1 to 30 mol%, more preferably 1 to 20. It should be mol%.

A mixed powder prepared by mixing a predetermined amount of these raw materials is heated and melted at 600 ° C. or higher, and rapidly cooled to a temperature below the glass transition point to obtain an up-conversion type transparent vitreous phosphor used in the present invention. You can

In order to manufacture the wavelength conversion type light emitting panel of the present invention, it is necessary to mold this transparent glassy phosphor into a sheet. This sheet of glassy phosphor can be easily manufactured by using the same method as that for manufacturing plate glass. That is, a melt obtained by heating and melting the above-mentioned mixed powder at 600 ° C. or higher, or a melt obtained by reheating and melting the glassy phosphor obtained by quenching this melt,
When poured into a bath of metal and cooled, a glassy phosphor in the form of a transparent sheet is obtained.

The sheet of the glassy phosphor thus molded is usually as thin as 1 to 2 mm, and therefore structurally weak.
In particular, since the chloride-based glassy phosphor is inferior in moisture resistance, strength and durability of this sheet alone are insufficient. In order to impart sufficient strength and durability to this sheet, in the present invention, this transparent glassy phosphor is sandwiched between two transparent bodies (sheets or films) Of the sandwich structure.

As the transparent body, a transparent sheet such as a glass plate, a transparent plastic plate (eg, a transparent resin plate such as acrylic resin or polycarbonate), or a transparent plastic film (eg, a film such as polyethylene, polypropylene or polyethylene terephthalate), etc. Transparent film can be used.

The thickness of each part of this laminate is not particularly limited, but the outer transparent body has a thickness of 0.1 to 10 mm. The phosphor is usually 1 to 2 mm as described above, but it may be thinner or thicker.

In order to prevent the intrusion of water or moisture from the outside, the periphery of the sandwich structure is sealed. For example, when the transparent body is a transparent plate made of glass or plastic, a sealing material such as silicone may be injected into the periphery. When the transparent body is a transparent film, it may be sealed with an adhesive or thermocompression bonded.

In this way, the transparent wavelength conversion type light emitting panel of the present invention is manufactured. When it is irradiated with infrared laser light or red laser light, it emits visible light having a lower wavelength. In general, a light source such as an infrared lamp cannot give sufficient energy for excitation. Excitation light sources that can be used include infrared semiconductor lasers with wavelengths of 1500, 980, 810 and 780 nm, and wavelengths of 600, 635 and 650.
There is a 700 nm band red semiconductor laser. For example, in the phosphor containing Gd as the main component, Er
^When doped with ³⁺ , it emits green light at 550 nm by irradiation with laser light at 810, 980, or 655 nm, and when doped with Ho ³⁺ , it is irradiated by irradiation with laser light at 650 nm.
It emits blue light of 0 nm.

In the light emitting panel of the present invention, if the above-mentioned phosphor containing Gd halide as a main component is used as the phosphor,
It does not require pre-excitation and emits high-intensity light instantly upon irradiation with infrared or red laser light, and has excellent durability. Therefore, this light-emitting panel can be used for window glass, partitions, guide plates, ceiling plates (parking lots, arcades, etc.), hoods, etc. (displays) or decorations (illuminations).

In order to make a predetermined region of a panel emit light in a pattern for the purpose of display or decoration using the light emitting panel of the present invention, for example, only a portion of the panel where light emission is not desired is transparent (visible light is transmitted). ), Block infrared
Material that absorbs (eg IT that has a high near-infrared blocking effect)
Paint containing O <Sn-doped indium oxide> fine powder)
Should be applied. The coating film formed is transparent,
The entire panel is transparent when it is not irradiated with infrared laser light. However, when the panel is irradiated with infrared laser light, since infrared rays are not absorbed by the coating film and reach the phosphor in the portion where the above coating is applied, no light emission occurs, and only the portion that is not applied emits light. A light emitting pattern is formed.

When the irradiation light is red laser light,
Similarly to the above, a coating that absorbs red light may be applied only to the portion where light emission is not desired. In this case, the paint that absorbs red light is generally bluish, but since the fluorescence generated by the light emission has high brightness, the light emission pattern can be clearly recognized.

It is also possible to previously form a pattern on the light emitting panel itself. That is, it is possible to partially dispose the glassy phosphor that emits light in a desired pattern, instead of disposing it as a continuous sheet on the whole when laminating panels. For example, a large number of disc-shaped, rectangular-shaped, or strip-shaped glassy phosphors can be arranged to emit light in the form of dots or stripes. The present invention also includes a light emitting panel including a laminated body having a structure in which the glassy phosphor is patterned and sandwiched between two transparent bodies as described above. In that case, it is preferable to fill the gap where the glassy phosphor does not exist with an appropriate transparent sealing material.

To irradiate the entire surface of the light emitting panel with the laser light, the laser light may be scanned along the panel.
Since the fluorescence emitted from the light-emitting body has afterglow, it is perceived by the human eye as a continuous pattern even when the fluorescence is emitted by scanning with such laser light. At this time, the pattern light emission can be performed by scanning only a specific portion instead of scanning the entire panel with the laser light. For example, by storing this scanning pattern in a computer, various patterns of light emission can be generated under computer control. If desired, two or more laser lights may be used.

[0028]

EXAMPLES Examples and comparative examples of the present invention will be shown below, but these examples are illustrative and do not limit the scope of the present invention.

(Example 1) As shown in Nos. 1 to 6 of Table 1,
Mix the raw material powders at the specified mixing ratios, put them in a crucible and melt them in an electric furnace at 600 ℃ for 15 minutes, then at 250 ℃ beforehand.
Pour 42g each onto molten Sn in a bath (10 × 10 cm, depth 5 cm) where Sn metal was melted, and make a transparent sheet of about 1 mm thickness consisting of 6 types of glassy phosphors No. 1 to 6 Obtained.

The periphery of each of the obtained phosphor sheets was ground by a grinder to make it smooth, and the size was adjusted to about 9.5 cm square. Then, two commercially available soda lime glass (10 × 10 × 0.2 cm) fluorescent plates were used. Then, the periphery was sealed with a commercially available silicone (KE422 manufactured by Shin-Etsu Silicone) to produce a transparent light emitting panel.

Each of the obtained wavelength conversion type light emitting panels was irradiated with a semiconductor laser beam having a wavelength shown in Table 1 at one point, and as a result, green light or blue light having a wavelength shown in Table 1 was instantaneously emitted. . Then, as a durability test, each of the obtained light emitting panels was left for 2 weeks under the conditions of a temperature of 40 ° C. and a humidity of 95%, and then laser light was irradiated in the same manner as above to examine the light emitting property. As a result, the emission intensity was almost unchanged before and after the test. On the other hand, when the phosphor was left alone in the same manner and tested for its light emitting property, no light emission was observed even when irradiated with laser light.

[0032]

[Table 1]

(Example 2) In the same manner as in Example 1, a transparent sheet of about 9.5 cm square of 6 kinds of glassy phosphors was prepared from the raw material powders having the predetermined mixing ratio shown in Table 1, and each phosphor sheet was prepared. Is sandwiched between two 10 × 10 cm transparent plastic sheets obtained by cutting a commercially available polycarbonate sheet (thickness: about 2 mm), and the periphery is sealed in the same manner as in Example 1 to form a transparent light emitting panel. It was made.

The obtained wavelength conversion type light emitting panel was irradiated with laser light in the same manner as in Example 1, and as a result, light was emitted in the same instant. Further, as a result of performing a durability test in the same manner as in Example 1, the light emitting intensity of the light emitting panel produced in this Example did not change, whereas no light emission was observed in the case of only the phosphor.

(Example 3) In the same manner as in Example 1, a transparent sheet of about 9.5 cm square of 6 kinds of glassy phosphors was prepared from the raw material powders having the predetermined mixing ratio shown in Table 1, and each phosphor sheet was manufactured. Was sandwiched between two 12 × 12 cm transparent plastic films obtained by cutting a commercially available polypropylene film (thickness: approximately 200 μm), and the periphery was sealed with a thermocompression bonding device to produce a transparent light emitting panel. .

The obtained wavelength conversion type light emitting panel was irradiated with laser light in the same manner as in Example 1, and as a result, light was emitted in the same instant. Further, as a result of performing a durability test in the same manner as in Example 1, the light emitting intensity of the light emitting panel produced in this Example did not change, whereas no light emission was observed in the case of only the phosphor.

(Example 4) A near-infrared ray-blocking transparent paint (trade name PI-2, made of acrylic resin, manufactured by Mitsubishi Materials) was applied to one surface of a light-emitting panel manufactured with the composition No. 2 in Table 1 of Example 1. A coating material in which infrared ray blocking ITO powder was dispersed) was applied in a checkered pattern of 3 mm square, and the entire surface of the panel was irradiated with scanning semiconductor laser light having a wavelength of 1500 nm to examine the light emitting property. As a result, a portion not coated with the above-mentioned paint instantly emitted blue-green light, and a coated portion did not emit light, and a clear checkered pattern could be recognized.

[0038]

As described above, the wavelength conversion type display panel of the present invention instantly emits blue light or green light upon irradiation with infrared rays or red light, and is capable of various patterned light emission. is there. In addition, the panel structure sandwiched between two transparent bodies enhances the durability of the phosphor and enables it to be used not only indoors but also outdoors for displays and illuminations. Expands the applications of transparent phosphors in molds.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Okubo 1-297 Kitabukuro-cho, Omiya-shi, Saitama Mitsubishi Materials Corporation

Claims (2)

[Claims] 1. A transparent wavelength conversion type light emitting panel having a structure in which a sheet of a transparent glassy phosphor for converting infrared or red laser light into visible light of a lower wavelength is sandwiched between two transparent bodies. . 2. The glassy phosphor comprises a gadolinium (Gd) halide as a main component of a glass base material, an alkaline earth metal chloride as a glass forming aid, and a rare earth halide as an emission center. Containing 1
The light emitting panel described.