Two-dimensional color code and a reader for the two-dimensional color code

Abstract

Detects the precise color of a 2D color code formed using structural color. [Solution] The two-dimensional color code of the present invention records information by combining multiple cells formed by structural colors. Furthermore, since the concave curved surface of the substrate is formed, and the concave curved surface is a curved surface formed by rotating a straight line parallel to the axis around the axis, it is possible to provide a two-dimensional color code and a reading device for the two-dimensional color code that can accurately detect the structural color using the inscribed angle theorem.

Description

Technical Field

[0001] The present invention relates to a two-dimensional color code and a reading device for the two-dimensional color code, and more particularly, to a two-dimensional color code formed by structural color and a reading device for the two-dimensional color code.

Background Art

[0002] A two-dimensional code is a matrix-type code that can be read by a scanner, and information can be recorded by a pattern formed by a combination of cells. Therefore, it is widely used in the fields of manufacturing and logistics, such as the receipt and dispatch, inventory management, picking, and distribution management of goods.

[0003] Patent Document 1 discloses a two-dimensional color code that can record more information than a black-and-white two-dimensional code.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, a two-dimensional color code formed by a conventional paint containing a dye or the like is likely to change color when exposed to ultraviolet rays. For example, when used for an object that is used over a long period of time, such as an automobile, it is impossible to guarantee the reading accuracy.

[0006]

[0007] ​This invention has been made in view of the problems of the prior art, and its objective is to provide a two-dimensional color code that can accurately detect colors and a device for reading the two-dimensional color code. [Means for solving the problem]

[0008] The inventors, after diligent research to achieve the above objective, discovered that the objective can be achieved by forming a two-dimensional color code using structural color on the inner surface of a recess formed on a rotating surface of constant curvature, and by arranging a light source and a color detector on the circumference of the rotating surface, thus completing the present invention.

[0009] In other words, the two-dimensional color code of the present invention is a two-dimensional color code that records information by combining multiple cells formed by structural colors. Furthermore, it is formed on the concave surface of the base material, and the concave surface is a surface of rotation formed by rotating a straight line parallel to the axis around the axis.

[0010] Furthermore, the reading device of the present invention is a reading device for reading the above-mentioned two-dimensional color code, and comprises a laser light source, a color detector, a support member that supports the laser light source and the color detector, and a reading window for placing the above-mentioned two-dimensional color code. Furthermore, the reading window has a positioning unit for positioning the two-dimensional color code in a predetermined location, and the support member is positioned such that the light source and the color detector are on the circumference of the rotating curved surface of the two-dimensional color code placed in the reading window. This system is characterized by reading the two-dimensional color code placed in the above-mentioned reading window. [Effects of the Invention]

[0011] According to the present invention, a two-dimensional color code is formed using structural color on the inner surface of a recess formed by a rotating curved surface with constant curvature, and a light source and a color detector are arranged on the circumference of the rotating curved surface. This provides a two-dimensional color code and a reading device for the two-dimensional color code that can accurately detect the structural color. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an example of a two-dimensional color code according to the present invention. [Figure 2] This is a diagram illustrating the inscribed angle theorem. [Figure 3] This figure shows an example of the reading device of the present invention. [Modes for carrying out the invention]

[0013] <2D color code> The two-dimensional color code of the present invention records information through a combination of multiple cells formed by structural colors and arranged in a two-dimensional array, and is formed on the concave curved surface of the substrate, as shown in Figure 1.

[0014] The concave surface described above is a surface of rotation formed by the rotation of a straight line parallel to the axis around the axis; in other words, it is a surface formed by a cut pipe, which is a circular pipe cut in the lengthwise direction, and has a constant radius of curvature.

[0015] Thus, since the two-dimensional color code of the present invention is formed on a concave surface with a constant radius of curvature, as shown in Figure 2, by utilizing the inscribed angle theorem, which states that the inscribed angle subtended by a single circular arc A is constant, the angle between the light I incident on the two-dimensional color code from the light source and the reflected light D reflected by the two-dimensional color code can always be kept constant. This eliminates the problem unique to structural colors, where the color tone changes depending on the observation angle, and makes it possible to detect accurate colors.

[0016] The above-mentioned cells can be formed by structural colors exhibited through thin-film interference, multilayer reflection, or fine surface texture, and can be formed, for example, by inkjet printing technology using structural color inks from Fujifilm Corporation.

[0017] Furthermore, examples of the two-dimensional color codes mentioned above include QR codes (registered trademark) and other two-dimensional codes such as Data Matrix.

[0018] <Reading device> The reading device of the present invention is a reading device that reads the above two-dimensional color code. As shown in FIG. 3, it includes a laser light source, a color detector such as a color sensor or an optical detector, a support member that supports the laser light source and the color detector, and a reading window for arranging the two-dimensional color code.

[0019] The reading window has a positioning portion for arranging the two-dimensional color code at a predetermined position. As a result, since the position of the two-dimensional color code in the reading device is fixed, it becomes possible to specify the circumference where the laser light source and the color detector should be arranged from the predetermined radius of curvature of the two-dimensional color code.

[0020] Examples of the positioning portion include the frame of the reading window and locating pins. By making the frame shape of the reading window and the edge shape of the base material of the two-dimensional color code fit exactly, or by forming holes in the base material of the two-dimensional color code for inserting the locating pins, the two-dimensional color code can be arranged at a predetermined position.

[0021] The support member is a support member dedicated to a specific two-dimensional color code having a certain radius of curvature. In advance, the shape of the support member is set so that the laser light source and the color detector are arranged on the circumference of the rotating surface shown by the dotted line in FIG. 3.

[0022] Therefore, the laser light source and the color detector supported by the support member are always arranged on the circumference of the rotating surface. So, when reading the two-dimensional color code, there is no need to adjust the laser light source and the color detector to be arranged on the circumference of the rotating surface.

[0023] This support member is replaceable. When reading another two-dimensional color code with a different radius of curvature, it becomes possible to read another two-dimensional color code with a different radius of curvature by replacing it with a support member corresponding to the radius of curvature of that two-dimensional color code.

[0024] The support member described above includes a circular rail and supports the laser light source and the color detector so that they can move along the circular rail.

[0025] The laser light source and color detector, supported on the circular rail described above, move in the same direction along the circumference of the rotating curved surface along the rail, while rotating on the circular rail, thereby changing the irradiation angle of the laser beam and the angle of the detection surface.

[0026] Then, the device is rotated on the circular rail so that the normal of the cell to be read is the bisector of the angle between the irradiation direction of the laser light source and the direction perpendicular to the detection surface of the color detector, and the two-dimensional color code is scanned in the circumferential direction to read one cell at a time.

[0027] In this case, it is preferable that the circumferential beam width of the laser light source is less than or equal to the circumferential width of the cell, and that the circumferential detection width of the color detector is less than or equal to the circumferential width of the cell. This allows for accurate color detection of each cell individually without being affected by reflected light from adjacent cells. In this invention, "beam width" is defined as the light intensity being 1 / e of the maximum intensity. 2 This refers to the width at the point where it becomes [a certain shape].

[0028] If the laser light source and the color detector are located on the circumference, and the relative distance between the light source and the color detector is constant, then the angle between the laser light from the light source and the reflected light will always be constant according to the inscribed angle theorem. However, since a two-dimensional color code has width in the circumferential direction, if the light source and detector are scanned circumferentially while keeping their orientations fixed, the angle of incidence of the laser light to the cell and the direction of the reflected light received by the detector will differ.

[0029] As the laser light source and the color detector move and rotate in the same direction along the circumference, the angle of incidence of the laser light and the direction of the reflected light received by the detector are always the same for all cells. Combined with the beam width, this allows for accurate color detection for all cells.

[0030] Furthermore, it is preferable that the wavelength range of the laser light irradiated onto the cell by the laser light source is 400 to 780 nm.

[0031] If the wavelength range of the laser light is within the above range, not only can it irradiate almost all colors in the visible light spectrum, but because the upper limit on the longer wavelength side is 780 nm and it does not include light at 800 nm, which is a double of 400 nm on the shorter wavelength side, it is possible to prevent light at wavelengths that are double the wavelength of the accurate color that should be detected from being amplified and detected by periodic structures that exhibit structural color, thereby enabling accurate color detection.

[0032] The wavelength range of the laser light mentioned above can be adjusted by filtering out light outside the wavelength range irradiated onto the cell.

[0033] The axial direction of the rotating curved surface may be scanned by moving the support member together with the support member, or by moving the laser light source and color detector in the axial direction on the support member. However, it is preferable that the laser light source is a line light source that extends in the axial direction of the rotating curved surface.

[0034] Because the above-mentioned line light source has a length that extends across the entire axial direction of the rotating surface of the 2D color code, it can detect the color of cells aligned in the axial direction at once, thereby improving the reading speed. [Explanation of Symbols]

[0035] 1. 2D color code 11 Base material 12 Structural colors 2. Reader 3. Laser light source 4-color detector 5 Reading window 51 Positioning section 6. Support Member 61 rails

Claims

1. A two-dimensional color code that records information through a combination of multiple cells formed by structural colors, Formed on the concave curved surface of the substrate, A two-dimensional color code characterized in that the concave surface described above is a surface of rotation formed by rotating a straight line parallel to the axis around the axis.

2. A reading device for reading a two-dimensional color code as described in claim 1 above, The system comprises a laser light source, a color detector, a support member supporting the laser light source and the color detector, and a reading window for arranging the two-dimensional color code. The above reading window has a positioning unit that places the two-dimensional color code in a predetermined position, The above-mentioned support member is positioned such that the above-mentioned light source and the above-mentioned color detector are placed on the circumference of the rotating curved surface of the two-dimensional color code placed in the reading window, A reading device characterized by reading a two-dimensional color code placed in the above-mentioned reading window.

3. The above support member is equipped with a circular rail, The above laser light source and the above color detector, The rail of the support member described above moves along the circumference of the rotating curved surface of the two-dimensional color code placed in the reading window described above, and, The normal of the cell to be read is the bisector of the always equal angle between the irradiation direction of the laser light source and the direction perpendicular to the detection surface of the color detector, the support member rotates on the rail, The reading device according to claim 2, characterized in that it scans and reads the above two-dimensional color code in the circumferential direction.

4. The reading device according to claim 3, characterized in that the circumferential beam width of the laser light source and the circumferential detection width of the color detector are less than or equal to the circumferential width of the cell.

5. The reading device according to claim 2, characterized in that the laser light source has a laser light wavelength range of 400 to 780 nm.

6. The reading device according to claim 2, characterized in that the laser light source is a line light source extending in the axial direction of the rotating curved surface.

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