JP2003019863A - Transparent inorganic material which can form heterogeneous part in optional shape showing behavior different from surroundings when irradiated with ultraviolet ray, and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display material which can make an image existing as a heterogeneous part formed by being irradiated with pulse laser beams very narrow in width actually in a transparent material unable to indicate the image directly visible. SOLUTION: By exciting a specimen piece including the heterogeneous part by ultraviolet rays, a behavior different from the surroundings of the heterogeneous part, for example the generation of fluorescence, is made to occur in the heterogeneous part so that the shape of the heterogeneous part is made visible. By moving the focus of the ultraviolet rays according to a prescribed pattern, an optional image, which can not be recognized directly by an outsider but is indicated for the person concerned as required, can be recorded in a visible form.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention irradiates a solid phase of a transparent inorganic material (transparent body) with at least one kind of pulsed laser light having a pulse width of 1 ps (1 picosecond = 10 ⁻¹² sec) or less, and is specified. By recording an image in the form of a latent image (invisible image) and irradiating the entire sample piece containing the recorded latent image with ultraviolet rays, a tangible object containing a foreign part of any shape that behaves differently from the surroundings. The present invention relates to a method for manufacturing a molded article, a manufacturing method in which the material is a display material, and a molded body in which an image is recorded as a latent image by the manufacturing method, and the recorded latent image is irradiated with ultraviolet rays and displayed in a fluorescent form.

More specifically, the present invention condenses and irradiates at least one kind of pulsed laser light having a pulse width of 1 ps or less on an arbitrary position in a solid phase of a sample piece made of a transparent inorganic material to form a latent image of a heterogeneous portion having an arbitrary shape. When formed (recorded) in the form of (invisible image), when the entire area of the sample piece is irradiated with ultraviolet light, the sample piece behaves differently from its surroundings. The present invention relates to a display material and a molded body which enable the position and / or shape of the above-mentioned foreign portion to be recognized from the outside, and a manufacturing method thereof.

[0003]

2. Description of the Related Art Conventionally, transparent inorganic materials, typically silicate glass, quartz glass, etc. , A method of forming a heterogeneous part of arbitrary shape at and around the focal point and performing white marking caused by light scattering, and using the marked article obtained thereby as various materials for recording, identification, decoration, etc. Is known.

In addition, by selecting an arbitrary point in the solid phase of a transparent inorganic material containing at least one selected from rare earth ions and transition metal ions as a focusing point, and irradiating the point with pulsed laser light by focusing. It is also known to form a heterogeneous portion having an arbitrary shape at and around the focal point to cause light absorption and / or long afterglow emission.

For example, Chinese patent ZL97234928.6
(International Application No.PCT / CN98 / 00100) is a glass surface or the inside of which CO ₂ laser light or YAG laser light is focused and irradiated,
It discloses a device or the like for cracking or damaging glass to engrave it and form a three-dimensional image therein. In addition, the marking formed by irradiating the known YAG laser light is limited to white, so image formation of various colors (marking provided)
Still had room for research.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transparent inorganic material in which a previously recorded latent image can be recognized for the first time from the outside by using fluorescence generated by irradiation of ultraviolet rays. More specifically, the object of the present invention is to irradiate a sample piece containing an image recorded as a latent image in a solid phase of a transparent inorganic material with ultraviolet rays so that a behavior different from that of the surroundings, for example, a heterogeneous portion exhibiting fluorescence emission can be obtained. To form. Further, the second object of the present invention is that the transparent inorganic material is useful in, for example, a large-capacity three-dimensional / optical memory, a three-dimensional display, an information recording medium, an information display medium or a decorative body by the above irradiation treatment. It is to provide as a raw material.

[0007]

SUMMARY OF THE INVENTION The present invention is to achieve a desired effect by combining the following constituents: (1) Setting a focusing point at an arbitrary position in a solid phase of a transparent inorganic material. Then, by irradiating and irradiating the pulsed laser light with a pulse width of 1 ps or less, a solid material having a heterogeneous portion of an arbitrary shape that behaves differently from the surroundings when irradiated with ultraviolet rays in the solid phase is manufactured. how to. (2) The method for producing a tangible object according to the above item 1, wherein the behavior different from the surroundings when exposed to ultraviolet rays is fluorescence emission. (3) The display material according to the above item 1 or 2, wherein the transparent inorganic material is an amorphous glassy material. (4) The display material according to the above item 1 or 2, wherein the transparent inorganic material is a crystalline solid. (5) Due to the behavior different from the surroundings when the foreign portion of arbitrary shape formed by the manufacturing method described in the above item 1 or 2 is irradiated with ultraviolet rays at an arbitrary position in the solid phase of the transparent inorganic material, A display material contained as a display that can be recognized as a specific character, symbol, graphic or sign for the first time from the outside. (6) Irradiation with ultraviolet light on a heterogeneous portion of arbitrary shape formed by pulsed laser light irradiation with a pulse width of 1 ps or less at an arbitrary position in the solid phase of one or more molded bodies selected from plate-like bodies, tubular bodies and containers The molded article according to any one of items 3 to 5, which is a display that is recognized as a specific character, symbol, figure, or sign from the outside for the first time due to a behavior different from that of the surroundings.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION <Pulse laser light having a pulse width of 1 ps or less> Laser light having a pulse width of 1 ps or less in the manufacturing method, the display material and the molded article of the present invention (hereinafter referred to as "extremely narrow pulse laser light"). It is preferable to use an extremely narrow pulse laser light such as a femtosecond (fs; 10 ⁻¹⁵ s) laser light. This ultra-narrow pulsed laser light is a non-resonant pulsed laser light that is not easily absorbed by the transparent inorganic material, such as argon (A
r) Laser-excited Ti-sapphire-laser light can be mentioned.

The "fs laser light" preferably used in the present invention is "pulse laser light having a pulse width of 1 ps or less", and its pulse width is 1 × 10 ^{-15 to} 999 × 1.
0 is a meaning of ^{-1 5} sec of the pulse laser beam. The pulse width of the fs laser light used to achieve the object of the present invention is usually 1
It is 0 × 10 ^{−15 to} 800 × 10 ⁻¹⁵ sec. In order to oscillate the above pulsed laser, various pumping light sources, for example, xenon (Xe) lamp, tungsten (W) and iodine
A (I) lamp or a mercury (Hg) lamp can be used. If a pulsed laser is oscillated by irradiation with these pumping light sources, laser emission can be generated when electrons return from the excited state to the ground state.

<Transparent Inorganic Material> The transparent inorganic material used in the method of the present invention is at least one highly transparent material selected from transparent amorphous materials and transparent crystalline materials. In the present invention, the transparent amorphous material and the transparent crystalline material may be collectively referred to as a "high transparency". As an example of the inorganic chemical component of the highly transparent body, at least one selected from oxides, halides and chalcogenides is used.
A class of compounds may be mentioned.

Among the above-mentioned highly transparent materials, examples of the amorphous material include silicate (silicate) glass, boro-silicate (borosilicate) glass and quartz glass. Among these transparent inorganic glasses, the silicate glass is preferable from the viewpoint of easy availability, but potassium silicate glass (commonly referred to as `` potassium glass '' in terms of excellent chemical stability and heat resistance). )). Borosilicate glass (for example, registered trademark: Pyrex) is used in fields where stricter heat resistance is required.
(R) (manufactured by Dow Corning Co., Ltd.)] is suitable, and quartz glass is suitable for the field requiring the most severe heat resistance.

The transparent crystalline material used in the method of the present invention is preferably a single crystal composed of silicon dioxide such as quartz and calcite, fluorite (mainly calcium fluoride), rock salt (mainly sodium chloride). ) And the like. Some sodium chloride and potassium bromide are provided as synthetic single crystals. As the single crystal actually used, a synthetic single crystal is preferable. The reason for this is that the crystal lattice is well-ordered and that other contaminant compounds are not contained.

<Rare Earth Ions> Examples of rare earth ions that can be added as a dopant to the transparent inorganic material used in the method of the present invention include Eu ions, Dy ions, Pr ions, Tb ions, Ce ions, Nd ions, Sm ions, Yb. Ions and Tm ions may be mentioned. Preferred among these rare earth ions are Sm ions and Eu.
Ion.

<Transition metal ion> Examples of the transition metal ion which can be added as a dopant to the transparent inorganic material used in the present invention include Mn ion, Cr ion and Ti.
Ions can be mentioned. <Heavy Metal Ion> Further, examples of heavy metal ions that can be added as a dopant to the transparent inorganic material used in the present invention include Ag ions, Au ions, and Bi ions. Of these, the preferred heavy metal ion is Ag ion.

<Amount of Rare Earth, Transition Metal or Heavy Metal Ion and Reference Amount> The amount of rare earth ion alone, the amount of transition metal ion alone and the amount of heavy metal ion used in the method of the present invention are used together in a preferred embodiment. The preferable amount of each of the transition metal ion, the rare earth ion, and the heavy metal ion is a value (cation%) with respect to the total amount of cations (sum of various cations) contained in the transparent inorganic material.

The content of each of the rare earth ion, transition metal ion and heavy metal ion used in the method of the present invention is based on the total amount of cations contained in the transparent inorganic material.
Rare earth ions usually 0.0005 to 10 cat%, preferably 0.002 to 5 cat%, transition metal ions usually 0.0005
-10cat%, preferably 0.002-5cat% and heavy metal ions usually 0.0005-10cat%, preferably 0.0
It is preferably set to 002 to 5 cat%.

<Adjustment of Converging Point> In the method of the present invention, in order to adjust the position of the converging point of the transparent inorganic material in the solid phase, the two are relatively moved and the solid phase of the transparent inorganic material is adjusted. A predetermined marking pattern (image shape) is formed inside as a latent image. This adjustment irradiates the ultra-narrow pulsed laser light while moving the focal point in accordance with a predetermined pattern, and the subsequent irradiation of ultraviolet rays collects a behavior different from the surroundings, for example, a heterogeneous portion of an arbitrary shape that exhibits fluorescence emission. It is generated in series at the light spot and its vicinity. An example of the feeding mechanism for carrying out the relative movement is a positioning device capable of finely adjusting the focal point in each of the front, rear, left, right, and top directions.

<Ultra-narrow-width pulsed laser light generator> A laser beam having a pulse width of 1 ps or less, preferably femtosecond (fs) used in the method of the present invention (sometimes referred to as "ultra-narrow-width pulsed laser light") is used. Examples of the device for generation include a solid-state laser light generator, a liquid laser light generator, and a gas laser light generator.

The ultra-narrow pulsed laser light used in the present invention has a pulse width of 1 ps or less, preferably fs (femtosecond).
The transparent inorganic material sample piece is irradiated with the pulsed laser light. <Use of transparent body irradiated with ultra-narrow width laser light> The inorganic transparent body (transparent inorganic material) which has been irradiated with laser light of one or more pulse widths of 1 ps or less, preferably fs or less by the method of the present invention is as follows. When irradiated with ultraviolet rays, the behavior that differs from the surroundings usually causes fluorescence emission. By utilizing this ability, it can be used in various applications as a recording material having polychromaticity and / or polymorphism, an identifying material, a display material for decoration, and the like.

[0020]

According to the method of the present invention, by focusing and irradiating the inside of a transparent inorganic material with an extremely narrow pulse laser beam having a focused point adjusted, the focused point inside the transparent inorganic material and the vicinity thereof. On the other hand, a foreign part that behaves differently from the surroundings is formed. In the subsequent irradiation of ultraviolet rays by this foreign portion, the image formed as a latent image is visually recognizable due to the contribution of exhibiting a behavior different from that of the portion not irradiated with the pulsed laser light.

As a result, the highly transparent body and the transparent inorganic material in which this kind of region is formed are useful as a large-capacity three-dimensional memory, a three-dimensional display, an information recording medium, an identification medium or a decorative material.

[0022]

EXAMPLES The method of the present invention will be specifically described below based on examples. However, the invention is in no way limited by these examples.

[0023]

Example 1 A sample piece (length 10 mm × width 10 mm × thickness 5 mm) was cut out from silicon dioxide (SiO ₂ ) glass having a hydroxyl group (OH) concentration of 1300 ppm, and its two parallel surfaces (two surfaces parallel to each other) were cut out. Optically polished. The fs pulsed laser light was focused by a 10 × objective lens so that the focal point was located inside the prepared sample piece, and the sample piece was focused and irradiated. The fs pulse laser light used here has a pulse width of 150 fs (femtosecond = 10 ⁻¹⁵ se)
c) The light flux had a repetition frequency of 1 kHz and a wavelength of 800 nm, and its peak energy was 2 × 10 ¹¹ W / cm ² .

The inside of the sample piece irradiated with the fs pulsed laser beam is irradiated with ultraviolet rays (wavelength: 35
(0 nm), and the emission spectrum was measured.
Green fluorescence was observed from the area irradiated with s-pulse laser light. In addition, no light emission was observed from the site not irradiated with the fs pulsed laser beam even when excited by ultraviolet rays.

[0025]

[Example 2] In order to prepare a transparent glassy material made of fluoride, the cation contents were expressed by the mutual ratio (mol%), and the raw materials SmF ₃ : 0.1 and YF ₃ : 14 were used. .9, MgF ₂ : 10,
CaF ₂ : 20, SrF ₂ : 10, BaF ₂ : 10 and AlF ₃ : 35 are weighed and housed in platinum crucibles,
After heating and melting at a temperature of 1150 ° C. for 30 minutes, the mixture was allowed to cool to room temperature to obtain a transparent glass.

A sample piece (length 10 mm × width 10 mm × thickness 5 mm) was cut out from the obtained Sm ³⁺ -containing fluoride glass material, and its two parallel surfaces (two surfaces parallel to each other) were optically polished. The fs pulsed laser light was focused by a 10 × objective lens so that the focal point was located inside the prepared sample piece, and the sample piece was focused and irradiated. The fs pulsed laser light used here is a pulse width of 500 fs oscillated from an argon laser pumped Ti-sapphire laser, a repetition frequency of 1 kHz and a wavelength of 400 nm.
Pulsed laser light flux with a peak energy of 5 ×
It was 10 ¹¹ W / cm ² .

With respect to the sample piece which was focused and irradiated with this fs pulsed laser light, the entire sample piece irradiated with the pulsed laser light was excited by ultraviolet rays (wavelength 350 nm). As a result of measuring the emission spectrum at that time, red fluorescence was observed from the site which had been irradiated with the fs pulsed laser light. In addition, orange emission due to ultraviolet irradiation was observed from the site not irradiated with the pulsed laser light.

[0028]

Example 3 To prepare a transparent glass material, AgPO ₃ :
8 wt%, KPO ₃ : 2.5 wt%, Ba (PO ₃ ) ₂ : 50 wt% and Al
(PO ₃ ) ₃ : 50 wt% of each was stored in a platinum crucible,
After heating and melting, the mixture was allowed to cool to room temperature to obtain a transparent glass. A sample piece (length 10 mm × width 10 mm × thickness 5 mm) was cut out from the obtained glassy material, and its 2 parallel surfaces (2 surfaces parallel to each other) were optically polished.

The sample piece was focused and irradiated with fs pulsed laser light by squeezing with a 5 × objective lens so that the focus point was located inside the prepared sample piece. The fs pulsed laser light used here is a light flux with a wavelength of 775 nm, a pulse width of 150 fs and a repetition frequency of 1 Hz, and its peak energy is 3 × 10 ¹¹ W /
It was cm ² . For the sample piece irradiated with fs laser light, the emission spectrum when excited with ultraviolet rays (wavelength 250 to 350 nm) was measured for the sample piece irradiated with fs laser light, and the sample was irradiated with fs laser light. Orange fluorescence was observed from the site. Further, no light emission was observed from the above-mentioned site not irradiated with the fs laser light, even when ultraviolet light excitation was performed.

[0030]

Example 4 Eu at a ratio represented by a molar ratio (mol%)
_{F 2: 0.1, YF 3:} 14.9, MgF 2: 10, CaF 2: 20, S
rF ₂ : 10, BaF ₂ : 10 and AlF ₃ : 35 are weighed as raw materials, respectively, and then they are all put into a platinum crucible,
A transparent glass material was obtained by heating and melting and then leaving to cool to room temperature.

Specimen piece from the obtained fluoride glass-like material
(Length 10 mm × width 10 mm × thickness 5 mm) was cut out, and two opposing parallel surfaces (two surfaces parallel to each other) were optically polished. The fs pulsed laser light was focused with a 10 × objective lens so that the focal point was located inside the prepared sample piece, and the sample piece was focused and irradiated. The fs pulsed laser light used here was a light flux with a pulse width of 150 fs, a repetition frequency of 10 Hz and a wavelength of 1550 nm, and its peak energy was 2 × 10 ⁹ W / cm ² .

As a result of measuring the emission spectrum of the sample piece irradiated with the above fs pulsed laser light when irradiated with ultraviolet light (wavelength 394 nm), it was found that the area irradiated with the above fs pulsed laser light was Red fluorescence was observed.
In addition, blue fluorescence due to ultraviolet excitation was observed from the above-mentioned site not irradiated with fs pulsed laser light.

[0033]

Example 5 A borate glass material doped with CdS and CdSe was prepared, and a sample piece (length 1) was prepared from the obtained glass material.
0mm x width 10mm x thickness 5mm) is cut out and it is facing 2
The parallel surfaces (two surfaces parallel to each other) were optically polished. The fs pulsed laser light was focused with a 10 × objective lens so that the focal point was located inside the prepared sample piece, and the sample piece was focused and irradiated.

The fs pulse laser light used here has a pulse width of 150 fs, a repetition frequency of 200 kHz, and a wavelength of 133.
With 0 nm luminous flux, its peak energy is 5 × 10 ⁹ W / cm ²
Met. As a result of observing the appearance of the sample piece when it was excited by ultraviolet rays (wavelength 350 nm), the sample piece irradiated with the above fs pulsed laser light was observed to emit light at the portion irradiated with the fs pulsed laser light. Was not done. On the other hand, from the site not irradiated with the fs pulsed laser light, orange fluorescence due to ultraviolet excitation was observed.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuyuki Hirao             3-5-8 Kizugawadai, Kizu-cho, Soraku-gun, Kyoto Prefecture             issue F-term (reference) 2H111 EA03 EA11 EA21 EA31 EA32                       FA00 FB31 HA14 HA21 HA32                       HA35                 4G059 AA02 AC15                 5C096 AA11 AA14 BA04 BC12 CA03                       CA12 CA28 CA33 CB07 CC02                       EA01 EA03 EB02 EB20 FA01                       FA05 FA13 FA14

Claims (6)

[Claims] 1. An ultraviolet ray is irradiated in the solid phase by setting a focusing point at an arbitrary position in the solid phase of the transparent inorganic material and focusing and irradiating a pulse laser beam having a pulse width of 1 ps or less. A method for producing a tangible object in which a foreign part having an arbitrary shape that behaves differently from the surroundings is formed. 2. The method for producing a tangible object according to claim 1, wherein the behavior different from the surroundings when exposed to ultraviolet rays is fluorescence emission. 3. The display material according to claim 1, wherein the transparent inorganic material is an amorphous glassy material. 4. The display material according to claim 1, wherein the transparent inorganic material is a crystalline solid. 5. A behavior different from the surroundings when a foreign portion of an arbitrary shape formed by the manufacturing method according to claim 1 or 2 is exposed to ultraviolet rays at an arbitrary position in a solid phase of a transparent inorganic material. For the first time, a display material contained as a display that can be recognized as a specific character, symbol, figure or sign from the outside for the first time. 6. 1 selected from a plate-like body, a tubular body and a container
For the first time, it is identified from the outside by the behavior different from the surrounding that the heterogeneous part of arbitrary shape formed by irradiation of pulsed laser light with a pulse width of 1 ps or less at an arbitrary position in the solid phase of at least one kind of molded body is exposed to ultraviolet light The molded article according to any one of claims 3 to 5, which is a display recognized as a character, a symbol, a figure, a sign, or the like.