JP2002318557A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device with which an effect of displaying characters and graphics can be obtained by aggregations of bright spots inside a transparent body and which can be easily worked. SOLUTION: In a transparent solid matter, by processing for drawing a predetermined display pattern by irradiating it with laser light from the outside, crack groups consisting of lots of cracks are generated along the display pattern inside of the solid matter, so as to be used as a display device. It is also provided with an illuminating means for illuminating the parts of the crack groups. Combination of a material of the solid matter, the kind of the laser used for the processing and processing conditions is set so that the surface of the solid matter is not processed but the crack groups of such a size as its pattern is discriminated only inside the solid matter are generated. An acrylic resin is used for the solid matter, and YAG laser is used as the laser. The frequency of the laser light is set to 20 kHz or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device capable of displaying characters and figures inside a transparent material by irradiating light.

[0002]

2. Description of the Related Art Heretofore, there has been a display device which displays a predetermined display pattern on the surface or inside of a transparent solid as if it were emitting light.
For example, when a display pattern (patterns, characters, etc.) is engraved shallowly on the surface of a transparent acrylic resin plate and light from a fluorescent tube or the like is introduced from the side of the plate, most of the illumination light cannot be seen from the front of the display plate. Some parts are seen to be scattered or refracted in the direction of the front by the engraved design or the like. In addition, light scattering fine particles (amorphous metal powder, metal foil pieces, transparent material strips or microspheres having a different color or refractive index from the base material, etc.) are dispersed in a base material made of a transparent member. embedded,
In some cases, this is illuminated from the side or obliquely from the front and rear to make the existing portion of the fine particles float with light.

[0003]

Since these can provide a fairly beautiful display as such, they cannot be said to have a particularly serious problem. However, in the context of the present invention,
In the first conventional example of engraving a base material, the outline of a display pattern tends to be too sharp, and a dreamy effect that blurs the periphery of the pattern tends to be difficult to obtain. In the second conventional example using light-scattering fine particles, it is not easy to embed the fine particles in a predetermined pattern in the base material. (For example, it is necessary to first engrave a groove in the base material, fill the groove with a material mixed with fine particles, and harden the groove. Also, such a processing method cannot avoid the sharpness of the contour.)

[0004] It is an object of the present invention to provide a display device in which the effect of displaying characters and figures by a set of luminescent spots inside a transparent body can be obtained, and the display pattern can be easily processed.

[0005]

To achieve the above object, the display device of the present invention has the following features. (1) A process of drawing a predetermined display pattern by irradiating a laser beam from the outside of a transparent solid to generate a crack group including a large number of cracks along the pattern inside the solid.

[0006] The display device of the present invention may further include at least one of the following features. (2) Illumination means for illuminating a certain portion of the crack group is further provided. (3) The combination of the material of the solid, the type of laser used for processing, and the processing conditions is such that the surface of the solid is not processed,
The setting is such that the crack group having such a size that the pattern can be identified only inside the solid. (4) The solid material is an acrylic resin, and the type of the laser is a YAG laser. (5) The energy per shot of the laser light is 1
Processing must not exceed 5 / 10,000J.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of a display device according to the present invention, wherein FIG.
(B) is an AA sectional view, and (c) is a BB sectional view.
In the figure, reference numeral 1 denotes a transparent member, which is a transparent and colorless acrylic resin plate (having a thickness of, for example, about 2 mm to 2 cm). Reference numeral 2 denotes display information processed (written) therein, which is composed of a group of fine cracks. Since it is difficult to accurately show the aggregation of the microcracks, a temporary pattern is used to indicate the approximate location of the inside of the member. The surface of the transparent member 1 is smooth. Therefore, as shown in (a) and (c), an illumination light source 3 such as an LED lamp is arranged on the side of the transparent member 1 to emit light, and direct light is shielded so as to be invisible to an observer.

When the illumination light 3a is guided into the inside of the transparent member 1 from an arbitrary surface (the left side in the figure), minute cracks reflect or scatter the light in various directions, and the display information 2 removes star dust. It shines beautifully as if strewn. Or it can be said that it resembles the shine of glass balls or transparent rubber balls mixed with silver foil powder. The display pattern is formed of irregular cracks, and the contour of the transparent member 1 is not clear because the surface is smooth. Further, since the minute cracks are generated in random directions, there is considerable freedom in the position of the illumination light source 3 and the direction (center) of the illumination light 3a. However, with respect to the area of the light source, light having directivity closer to a point light source than a surface light source seems to have a more favorable effect.

Next, a method of forming the display information 2 comprising a group of minute cracks will be described with reference to FIG. Reference numeral 4 denotes a laser device for processing, and in this example, a YAG laser was used. The pattern to be displayed is drawn by irradiating the beam-like laser light 4a onto the surface of the transparent member 1 from a direction substantially perpendicular thereto and moving it relatively. When observing the processing state, no trace or scratch of the processing remains on the surface of the transparent object 1 (at least as seen with the naked eye). It is considered that this is because the acrylic material has high transmittance with respect to the wavelength of the YAG laser light.

However, minute cracks are formed in the transparent member 1 within a certain depth range. The reason is that the laser beam focuses just around that depth,
It is likely that the energy density increases in the vicinity, and heat is generated to cause cracks. In fact, the crack depth could be adjusted by changing the focal position. Cracks can be started just below the surface, or a thin plate material can be formed as a crack layer having almost the full thickness. The determination of the depth may be related to impurities in the material or non-uniformity of optical characteristics due to molding. However, at present, these reasons are beyond speculation. The frequency of the laser of this example is 40 to 50 kHz, and the current value of the laser processing machine is 1
1 to 12 A, the output of the laser beam was 20 to 30 W, and the drawing speed was 400 to 500 mm / sec.

As a result of various experiments, it is the frequency of the laser beam that has a great influence on the processing result (display effect and beauty). At low frequencies, the size of each crack becomes too large to be seen as a pattern. I understood. In the above experiment, when the frequency of the laser beam was lower than 20 kHz, the contour of the display pattern was too rough. This is the energy per shot of the laser pulse (quotient of output divided by frequency)
However, it is almost appropriate in the range of the above experiment, that is, (4-8) / 10,000 J or less, and (10-15) / 1
This indicates that the display becomes difficult to see when the value exceeds about 0000 J. However, this is a condition relating to an English character pattern of about several mm square, and is not limited to a case where a larger or simpler display pattern is created. Note that the incident angle of the laser beam 4a with respect to the surface of the transparent member 1 and the state of the surface of the transparent member 1 (such as surface roughness) did not seem to significantly affect the processing result. Of course, this data can change depending on the material of the transparent member.

FIG. 2 shows a second embodiment of the present invention.
(A) is the front view, (b) is CC sectional drawing. In this example, an acrylic round bar was used as the transparent member 1. As the laser device 4, a YAG laser processing machine was also used. The processing conditions are almost the same as in the first embodiment. In this example, the surface of the transparent member may be a curved surface instead of a plane,
It also shows that the depth of the crack layer that occurs even on a curved surface does not change much. Illumination light 4a from end of round bar
, The drawn pattern emerges in the round bar as a set of bright spots.

The two embodiments of the present invention have been described above. Here, other embodiments and modifications of the embodiment of the present invention will be considered. First of all, it is a form as a display, but the illumination light source is not necessarily a special point light source, and the display effect can be obtained even with a handy light source such as sunlight or a general flashlight, so the combination with the illumination light source is not essential, A display pattern alone can be provided as a display, for example, in the form of an accessory, using only a processed transparent body.

Although it has been confirmed that the present invention can be practiced using an acrylic resin, crack groups may not be formed properly even with an acrylic resin if the material manufacturer is different. The reason has not been elucidated yet, but the degree of polymerization of the material resin may be related. Although this remains a problem for the future, experiments to investigate the degree of polymerization of the material or to change the degree of polymerization can be performed relatively easily with the help of an infrared spectrometer (FT-IR) or the like. I can't say.

As for the transparent member, another resin material was tested. However, the surface of the styrene resin or PET was shaved by a laser beam and did not become intact like an acrylic material. Although many combinations of laser light having a wavelength different from that of YAG and the material of the transparent member (considering coloring) and processing conditions have not been tried yet, some combinations may be successful. There is also a possibility that other types of transparent resin materials containing an acrylic resin are effective. There will be no inherent difficulty in finding it. It should be noted that even if the surface of the transparent member is uneven or melt-processed, if a crack layer can be formed in the back, a unique display effect can be obtained,
This can also be included in the technical scope of the present invention.

Further, in the embodiment of the present invention, it is possible to add processing for obtaining further different effects. For example, the surface layer or the back surface layer of the transparent member can be scraped off to form only a crack layer. Also, there is a possibility that the focal position of the laser beam is sequentially shifted and the crack layer can be stacked from the back to make it thicker. In addition, a prism-shaped transparent member is further bonded to a transparent member that has been processed normally from the vertical direction,
A crack layer having display information can be inclined with respect to the surface of the transparent member by processing by irradiating a laser beam obliquely.

A lens, a colored plate,
Alternatively, a member having another optical function, such as a pattern or another transparent plate having concavities and convexities, which can be combined with the display information, may be overlapped (these may be appropriately illuminated). As the illumination method, a plurality of light emitters can be used, the irradiation position or direction can be moved, a multicolor lamp can be used, or a flash or a laser beam can be used. Various other applications and modifications will be possible.

[0018]

According to the present invention, it is possible to provide a display device capable of displaying characters and figures by a set of luminescent spots inside a transparent body and easily writing display information. Further, the display device of the present invention can give various changes in display and has a wide range of application.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a front view, FIG. 1B is an AA sectional view, and FIG. 1C is a BB sectional view.

2A and 2B show a second embodiment of the present invention, wherein FIG. 2A is a front view thereof, and FIG.

[Explanation of symbols]

 Reference Signs List 1 transparent member 2 display information 3 illumination light source 3a illumination light 4 laser device 4a laser light

Claims (5)

[Claims] 1. A process of irradiating a laser beam from outside a transparent solid to draw a predetermined display pattern,
A display device, wherein a group of cracks including a large number of cracks along the pattern is generated inside the solid. 2. The display device according to claim 1, further comprising an illuminating means for illuminating a portion of the crack group. 3. The combination of the material of the solid, the type of laser used for the processing, and the processing conditions may be set such that the crack has a size such that the surface of the solid is not processed and the pattern is identified only inside the solid. 3. The display device according to claim 1, wherein a group is set to be generated. 4. The solid material is an acrylic resin,
4. The display device according to claim 3, wherein the type of the laser is a YAG laser. 5. The display device according to claim 4, wherein the laser beam is processed under a condition that energy per shot of the laser beam does not exceed 15 / 10,000 J.