JPS61269995A - Engraving method by laser light - Google Patents

Abstract

PURPOSE:To make possible the engraving of a realistic image on wood, etc. by a laser light by subjecting a mask material consisting of a metallic layer lined with a corrosion resistant film which is a base material to photoetching using a photomask of a halftone negative film to form a laser mask and using such mask. CONSTITUTION:The mask material (m) is formed by lining integrally the metallic layer 2 to the corrosion resistant film 1 which is the base material and laminating the photoresist film 3 on the surface of the metallic layer 2. The photomask 4 consisting of the halftone negative film formed preliminarily from a photographic original is superposed on the mask material (m) and the metallic layer 2 of the material (m) is etched away by photoetching method to form the laser mask LM having the metallic layer of the same pattern as the pattern of the mask 4 left on the film 1. Such LM is superposed on the surface of a material 5 to be worked and the laser light L is irradiated thereon from above, by which the pattern formed of the layer 2 is embossed on the surface of the material 5.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention utilizes the sharp directivity and high energy density properties of laser beams to create elaborate images such as figures and characters on wood or synthetic resin boards. on how to engrave.

(Prior art) This type of engraving method using a laser beam involves making a template by drilling holes in a pattern corresponding to the shape to be processed in a metal plate such as copper or brass that blocks the laser beam. A method of machining the same pattern as the holes in the template into the workpiece by stacking the template on the surface of the workpiece such as wood and irradiating the laser beam from above to burn off only the holes. is conventionally known (for example, Japanese Patent Publication No. 58-1523)
No. 2, JP-A-58-71000).

(Problem to be solved by the invention) However, with the conventional method using a template, it is impossible to drill a loop-shaped closed hole because part of the template falls off. A so-called bridge is required to keep the entire template together.

Therefore, in the past, it was impossible to carve the entire outer edge of a character or figure onto the surface of the workpiece to form a complete shape. Therefore, for example, when engraving a portrait or a painting, the engraving requires a certain design such as adding a bridge to the original image, so the finished sculpture has a different shape from the original and is less realistic. It was severely lacking.

In view of the above circumstances, an object of the present invention is to improve the conventional template to engrave a photo-realistic image on wood or the like using a laser beam.

(Means for Solving the Problems) In the present invention, a metal layer is first attached to a corrosion-resistant base film, and a photoresist film is laminated on the surface of the metal layer to form a mask material. Then, a photomask made of a mesh negative film formed in advance based on a photographic original is placed on the mask material, and the metal layer is punched out using a photoetching method.
This forms a laser mask that leaves a metal layer with the same pattern as the photomask on the base film.Next, the laser mask is superimposed on the surface of a workpiece such as wood.
A laser beam is irradiated onto the entire surface from above to burn off the area other than the area shielded by the metal layer, thereby embossing the pattern formed by the metal layer on the surface of the workpiece.

(Function) When the metal layer of the mask material is photo-etched using a net negative film photomaskler, the metal layer is etched into a mesh pattern with the same pattern as the dots of the photomask, but this metal layer has corrosion resistance. Since it is backed by the base film, the metal layer of each halftone dot is not separated into pieces but is held integrally on the base film.

When the workpiece is covered with the laser mask obtained in this way and a laser beam is irradiated from above, the workpiece surface other than the part blocked by the metal layer of the laser mask is evaporated to a certain depth. It is baked and shaved, and the same pattern as the metal layer, that is, the same pattern as the net negative of the photomask, remains on the processed surface and becomes embossed.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

1 is a base film with a thickness of about 20 to 50 L made of a corrosion-resistant material such as polyester that will not corrode by etching, and iron and copper.

A metal layer 2 made of brass-like metal with a thickness of 100 mm that can be etched and has no grooves is integrally laminated, and this metal layer 2 is
A photoresist film 3 is laminated on the surface of the mask material m.
(Figure 2).

The photoresist film 3 is a film-like resist that is attached to the metal layer 2.
It is formed by laminating the surface by applying heat and pressure, or by applying a liquid resist.

Next, this mask material m is photoetched, and the photomask 4 used at that time is a net negative film made as follows.

First, prepare a black-and-white continuous tone photographic original, such as a portrait, and photograph the original by placing a mesh screen (also called a contact screen) with small meshes in close contact with the emulsion surface of a photosensitive film, and then transfer it to a mesh negative film. make. This photosensitive film has the property that when exposed to light, the portions exceeding the critical exposure amount turn black 4a, and the portions below that amount become transparent 4b.

For this reason, the mesh on the mesh screen is uniform, but because the amount of light that passes through the mesh is small in dark areas of the original, when this photosensitive film is developed, it becomes small black dots, and in light areas (light areas), the amount of light that passes through the mesh is small. ) produces large black halftone dots due to the large amount of light, and a halftone negative film that is otherwise transparent.

This method of making mesh negative film is known as the halftone printing method, which is used to separate and print continuous tone manuscripts with continuous shading, such as photographs and paintings. In addition to shaped lines, parallel lines, broken lines,
There are various types of parts such as concentric circles, grains, etc., and you can use any of them, but it goes without saying that the shape of the halftone dots on the mesh negative film will differ depending on which one you use. When a mesh screen is used, the width of the black stripes is wide in dark areas of the original, and narrow in the light areas, and by changing the width of the parallel stripes in this way, continuous tones are tone-separated.

Alternatively, to make a mesh negative film, you can use a mesh screen to print an original such as a photograph onto a mesh positive photographic paper, and then turn the photographic paper over to make a mesh negative film. , printing on photographic paper has the advantage that the image can be easily corrected.

Once the net negative film is completed, apply it to photomask 4.
, overlap (masking) the above mask material m.
Photoetch.

To do this, the emulsion side of the mesh negative film is superimposed on the photoresist film 3 of the mask material m, and after close exposure using a vacuum printing frame (Fig. 2), the mask material m is immersed in a developer and developed. do. After the development is completed, the dissolved resist residue in the exposed area is washed away with water (Figure 3), and the metal layer 2 exposed from the resist film is corroded away by being sent to a corrosive machine (not shown) and sprayed with an etching solution. (chemical blanking) to form a laser mask LM on the base film 1, leaving a metal layer with the same pattern as the net negative film of the photomask. (Figure 4).

Next, this laser mask LM is closely attached to the surface of a workpiece 5 such as a synthetic resin such as acrylic resin or wood, and a laser beam such as an anthrax gas laser is irradiated onto the entire surface from above. In this case, by scanning the laser beam by moving the workpiece 5 and the laser beam relatively in the X- and Y-axis directions that intersect with each other, the entire surface of the laser mask LM can be accurately irradiated with the laser beam. .

When irradiated with a laser beam, the laser beam is blocked by the metal layer 2 and evaporates only the photoresist film 3 of the laser mask LM, but in the exposed portion of the base film 1, it passes through the base film 1 and is processed. The surface of the workpiece 5 is evaporated to a certain depth (1 mm to 3 mm) and a recess 6 is carved (Fig. 6). As a result, a pattern identical to the pattern of the metal layer 2 is formed on the surface of the workpiece 4. The same pattern as the net negative of Mask 4 remains on the processed surface and becomes embossed.
(Figure 1).

Thereafter, the metal layer 2 may be removed from the surface of the workpiece 4 together with the base film l, but an adhesive may be applied to the back surface of the base film l in advance and the laser mask LM is attached to the workpiece before laser beam irradiation. By adhering it to the surface of the material 5, at the same time as the predetermined pattern is embossed, a glossy metal layer having the same isthmus can be applied to the surface of the embossed pattern in one step. In this case, instead of applying adhesive to the back surface of the base film 1, the base film 1 and the workpiece 4 are
Needless to say, a double-sided adhesive sheet may be interposed between the two to bond the metal layer.

Furthermore, if the metal layer 2 is etched into a negative pattern compared to the above embodiment using a photoresist film that becomes soluble when exposed to light, the unevenness on the surface of the workpiece 5 will be exactly opposite to that shown in FIG. Become.

Furthermore, if a high-contrast film that emphasizes shading while eliminating neutral colors is used as a photomask instead of a net negative film, an image close to the original can be engraved on wood or the like.

(Effects of the Invention) In this way, in the present invention, since the corrosion-resistant base film 1 is laminated on the mask material m, which is the material for making the laser mask LM, the metal layer 2 can be punched out by photoetching. , since the metal layer 2 is held on the base film l and does not separate into pieces, there is no need for a conventional bridge to keep the template together, so there are no design issues when making a laser mask. In addition to this advantage, in the present invention, a mesh negative film made based on a photographic original is masked on a mask material as the photomask 4, and a laser mask is made by the photoetching method, so it is suitable for photographic printing. Laser mask LM with a fine halftone pattern made of a metal layer similar to the halftone plate used
can be formed.

Therefore, when this laser mask LM is placed over the workpiece and irradiated with a laser beam, a shape with the same pattern as the metal layer, that is, the same pattern as the net negative of the photomask, appears in the part blocked by the metal layer of the laser mask LM. It remains on the processed surface as an extremely fine halftone dot-like relief, and is processed into a shape similar to a relief plate for photographic printing, so when viewed as a whole, the original is determined by the size and area of the halftone dots on the processed surface. This has the effect of faithfully reproducing the shading and producing extremely realistic images.

According to the present invention, in addition to portraits and paintings, brush calligraphy and fish prints can be engraved by faithfully reproducing manuscripts, and can be widely used to decorate wood and the like.

[Brief explanation of the drawing]

FIG. 1 is an enlarged perspective view of a workpiece engraved by the method of the present invention, and FIGS. 2 to 6 are cross-sectional views showing each step of the engraving method according to the present invention. 1 is a base film, 2 is a metal layer, 3 is a photoresist film, 4 is a photomask, 5 is a workpiece, m is a mask material, L
M is a laser mask, L is a laser beam.

Claims (1)

[Claims] A photoresist film is laminated on the surface of a metal layer with a corrosion-resistant base film pasted on the back side to form a mask material, and a photomask made of a mesh negative film prepared in advance based on a photographic original is applied to the mask material. The metal layer of the mask material is punched out using a photo-etching method, thereby forming a laser mask that leaves a metal layer with the same pattern as the photomask on the base film, and then attaching the laser mask to the surface of the workpiece. An engraving method using a laser beam, characterized in that the pattern formed by the metal layer is embossed on the surface of the workpiece by superimposing the metal layer on the metal layer and irradiating the laser beam from above.