Scale, encoder, and method of manufacturing scale

Abstract

To prevent damage to an article such as a film or an element provided on the lower surface of a glass substrate.SOLUTION: A scale 100 includes a glass substrate 10 having a ground glass-like upper surface 11, a plurality of conductor patterns 20 arranged at predetermined intervals on the upper surface 11 of the glass substrate 10, and a conductor film 30 (article) provided on a lower surface 12 of the glass substrate 10. A method of manufacturing the scale 100 comprises a step of roughening the upper surface 11 of the glass substrate 10 into a ground glass shape, a step of forming the conductor film 30 on the lower surface 12 of the glass substrate 10, and a step of forming a plurality of conductor patterns 20 arranged at predetermined intervals on the upper surface 11 of the glass substrate 10 by laser processing after roughening the upper surface 11 of the glass substrate 10 into a ground glass shape and forming the conductor film 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a scale, an encoder, and a method for manufacturing a scale. [Background technology]

[0002] A scale used in an encoder or the like is known in which a resin layer having a mirror-like concave portion and a rough-surface convex portion is provided on a glass substrate, and a silicon oxide layer, an aluminum layer, and a silicon oxide layer are provided in that order on the convex portions (for example, Patent Document 1).It is also known that fine concaves and convexes can be formed on a glass surface by treating the glass surface with a solution in which ammonium sulfate, ammonium chloride, and ammonium nitrate are dissolved, either alone or in combination, in hydrofluoric acid, and sulfuric acid, hydrochloric acid, and nitric acid are added, either alone or in combination, as necessary (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-201906 [Patent Document 2] Japanese Patent Application Publication No. 7-237934 Summary of the Invention [Problem to be solved by the invention]

[0004] By forming a conductor pattern for the scale on the upper surface of the glass substrate using laser processing, it is possible to shorten the processing time when forming the conductor pattern and / or improve the processing reproducibility of the conductor pattern. When forming a conductor pattern on the upper surface of the glass substrate, a conductor film may be provided on the lower surface of the glass substrate to suppress warping of the glass substrate or, in the case of an electromagnetic induction type encoder scale, as an electromagnetic shield to suppress noise caused by the unevenness of the members below the mounting surface of the encoder device. In addition, a scale having elements that constitute reference points and circuits may be formed on the lower surface of the glass substrate. In this case, when forming a conductor pattern on the upper surface of the glass substrate using laser processing, the formations such as the film and elements provided on the lower surface of the glass substrate may be damaged by the influence of the laser that penetrates during processing, and defects may occur on the lower surface of the scale.

[0005] In one aspect, the present invention aims to prevent damage to structures such as films and elements provided on the lower surface of a glass substrate. [Means for solving the problem]

[0006] In one aspect, the scale of the present invention is characterized in that it comprises a glass substrate having a frosted upper surface, a plurality of conductor patterns arranged at predetermined intervals on the upper surface of the glass substrate, and a formation provided on the lower surface of the glass substrate.

[0007] In the above scale, the upper surface of the glass substrate may have a first region in which the multiple conductor patterns are provided and a second region located between the multiple conductor patterns, at least a portion of the second region adjacent to the first region being recessed with respect to the first region, and the second region may be formed deeper than the multiple conductor patterns at its boundary with the first region.

[0008] In the above scale, the bottom surface of at least a portion of the second region adjacent to the first region may have a surface roughness greater than that of the first region.

[0009] In the above scale, the lower surface of the glass substrate may be ground glass.

[0010] The scale may further comprise a resin film provided between the lower surface of the glass substrate and the formation, and the formation may be a conductive film.

[0011] In one aspect, an encoder according to the present invention is characterized in that it comprises the scale described above.

[0012] In one aspect, the method for manufacturing a scale according to the present invention is characterized by comprising the steps of roughening an upper surface of a glass substrate to a ground glass like state, forming a formation on a lower surface of the glass substrate, and, after roughening the upper surface of the glass substrate to a ground glass like state and forming the formation, forming a plurality of conductor patterns arranged at a predetermined interval on the upper surface of the glass substrate by laser processing.

[0013] The above-mentioned method for manufacturing a scale may further include a step of roughening the upper surface of the glass substrate to a ground glass like state, and then forming a conductor film on the upper surface of the glass substrate, and the step of forming the plurality of conductor patterns may include forming the plurality of conductor patterns by patterning the conductor film by laser processing.

[0014] The above-mentioned method for manufacturing a scale may further include a step of roughening the upper surface of the glass substrate to a ground glass like state, and then forming a plurality of temporary conductor patterns on the upper surface of the glass substrate, and the step of forming the plurality of conductor patterns may include forming the plurality of temporary conductor patterns by processing edge portions of the plurality of temporary conductor patterns by the laser processing. Effect of the Invention

[0015] This makes it possible to prevent damage to structures such as films and elements provided on the lower surface of the glass substrate. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1(a) is a diagram illustrating the configuration of an electromagnetic induction encoder with a scale according to the first embodiment, FIG. 1(b) is a diagram illustrating a detected sine wave signal, and FIG. 1(c) is a diagram illustrating a transmitting coil and a receiving coil. [Diagram 2] FIG. 2(a) is a plan view illustrating the scale according to the first embodiment, and FIG. 2(b) is a cross-sectional view taken along line AA in FIG. 2(a). [Diagram 3] 3(a) to 3(d) are cross-sectional views illustrating the method for manufacturing a scale according to the first embodiment. [Figure 4] 4(a) to 4(c) are cross-sectional views illustrating a method for producing a scale according to Comparative Example 1. [Diagram 5] FIG. 5(a) is a plan view illustrating a scale according to the second embodiment, and FIG. 5(b) is a cross-sectional view taken along line AA in FIG. 5(a). [Figure 6] FIG. 6(a) is a plan view illustrating a scale according to the third embodiment, and FIG. 6(b) is a cross-sectional view taken along line AA in FIG. 6(a). [Figure 7] 7(a) to 7(d) are cross-sectional views illustrating a method for manufacturing a scale according to the third embodiment. [Figure 8] 8(a) to 8(c) are cross-sectional views illustrating a method for producing a scale according to Comparative Example 2. [Figure 9] FIG. 9(a) is a plan view illustrating a scale according to the fourth embodiment, and FIG. 9(b) is a cross-sectional view taken along line AA in FIG. 9(a). [Figure 10] 10(a) to 10(d) are cross-sectional views illustrating a method for manufacturing a scale according to the fourth embodiment. [Figure 11] 11(a) to 11(d) are examples of images of the upper surfaces of the glass substrates of Samples A to D taken by an optical microscope. [Figure 12] 12(a) and 12(b) are cross-sectional views of devices fabricated using the glass substrates of Samples A to D. FIG. [Figure 13]13(a) to 13(d) are examples of images taken by an optical microscope of the upper and lower surfaces of device A fabricated using the glass substrates of samples A to D. FIG. [Figure 14] 14(a) and 14(b) are examples of images of the top and bottom surfaces of device B fabricated using the glass substrates of samples A and D, taken by an optical microscope. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment will be described with reference to the drawings.

[0018] (First embodiment) FIG. 1(a) is a diagram illustrating the configuration of an electromagnetic induction type encoder 1000 including a scale 100 according to the first embodiment. As illustrated in FIG. 1(a), the electromagnetic induction type encoder 1000 includes a scale 100 and a detection head 40 that moves relatively in a measurement axis direction. The scale 100 and the detection head 40 each have a substantially flat plate shape and are arranged facing each other with a predetermined gap therebetween. The electromagnetic induction type encoder 1000 also includes a transmission signal generating unit 50 and a displacement amount measuring unit 60. In FIG. 1(a), the X-axis represents the displacement direction (measurement axis) of the detection head 40. In the plane formed by the scale 100, the direction perpendicular to the X-axis is defined as the Y-axis. The direction perpendicular to the plane formed by the scale 100 is defined as the Z-axis.

[0019] The detection head 40 is provided with a transmitting coil 42, a receiving coil 44, etc. The transmitting coil 42 configures a rectangular coil having a length direction in the X-axis direction. The receiving coil 44 is disposed inside the transmitting coil 42.

[0020] The scale 100 has a plurality of conductor patterns 20 formed on the upper surface 11 of the glass substrate 10. The plurality of conductor patterns 20 are arranged along the X-axis direction with a fundamental period λ. The fundamental period λ corresponds to the distance between the centers of two adjacent conductor patterns 20 in the X-axis direction. The conductor pattern 20 is, for example, a plate-like pattern without holes or a closed loop coil. The conductor pattern 20 is electromagnetically coupled to the transmitting coil 42 and also to the receiving coil 44.

[0021] The transmission signal generating unit 50 generates a single-phase AC transmission signal and supplies it to the transmission coil 42. In this case, a magnetic flux is generated in the transmission coil 42. This generates an electromotive current in the multiple conductor patterns 20. The multiple conductor patterns 20 generate a magnetic flux that changes in a predetermined spatial period in the X-axis direction by electromagnetically coupling with the magnetic flux generated by the transmission coil 42. The magnetic flux generated by the conductor pattern 20 generates an electromotive current in the reception coil 44. The electromagnetic coupling between the conductor pattern 20 and the reception coil 44 changes depending on the displacement amount of the detection head 40. This allows a sinusoidal signal with the same period as the fundamental period λ to be obtained, as exemplified in FIG. 1(b). Therefore, the reception coil 44 detects the phase of the magnetic flux generated by the multiple conductor patterns 20.

[0022] The displacement measuring unit 60 can use this sine wave signal as a digital amount with minimum resolution by electrically interpolating it, and measures the displacement of the detection head 40. In FIG. 1(b), the horizontal axis represents the displacement of the detection head 40, and the vertical axis represents the output voltage of the receiving coil 44.

[0023] The transmitting coil 42, the receiving coil 44, and the conductor pattern 20, which are electromagnetically coupled to each other, form one track. Therefore, in this embodiment, the electromagnetic induction encoder 1000 has one track. Note that the electromagnetic induction encoder 1000 may have two tracks arranged at a predetermined interval in the Y-axis direction. In this case, the fundamental period λ may be different between the two tracks. This allows the encoder to function as an absolute (ABS) encoder.

[0024] Fig. 1(c) is a diagram illustrating the transmitting coil 42 and the receiving coil 44 provided in the detection head 40. As illustrated in Fig. 1(c), the receiving coil 44 is disposed inside the transmitting coil 42 which constitutes a rectangular coil. The receiving coil 44 is, for example, a circular coil, but may have other configurations.

[0025] Fig. 2(a) is a plan view illustrating a scale 100 according to the first embodiment, and Fig. 2(b) is a cross-sectional view taken along line AA in Fig. 2(a). As illustrated in Fig. 2(a) and Fig. 2(b), the scale 100 has a plurality of conductor patterns 20 provided on an upper surface 11 of a glass substrate 10, and a conductor film 30, for example, provided on a lower surface 12. The plurality of conductor patterns 20 are arranged at predetermined intervals along the X-axis direction. The plurality of conductor patterns 20 have a substantially rectangular shape with the Y-axis direction as the longitudinal direction in a plan view seen from the +Z direction.

[0026] The glass substrate 10 is formed of, for example, quartz glass, soda-lime glass, or non-alkali glass, but may be other materials. Quartz glass is glass that is composed almost entirely of silicon dioxide (SiO2) and contains very few impurities. Soda-lime glass is glass that contains silicon dioxide (SiO2) as a main component and also contains sodium oxide (Na2O) and calcium oxide (CaO). Non-alkali glass is glass that contains silicon dioxide (SiO2) as a main component and does not contain alkali components such as sodium and potassium. The thickness of the glass substrate 10 is, for example, about 0.5 mm to 5.0 mm.

[0027] The conductor pattern 20 is formed of a conductor such as copper, silver, gold, or aluminum. The thickness of the conductor pattern 20 is, for example, about 5 μm to 30 μm. The width of the conductor pattern 20 is, for example, about 500 μm to 3000 μm. The interval between the conductor patterns 20 is also, for example, about 500 μm to 3000 μm.

[0028] The conductive film 30 is formed of a conductor such as copper, silver, gold, or aluminum. The conductive film 30 is formed of, for example, the same material as the conductive pattern 20. The thickness of the conductive film 30 is, for example, 5 μm to 30 μm. The thickness of the conductive film 30 is, for example, approximately the same as the thickness of the conductive pattern 20, and may be 0.8 to 1.2 times, or 0.9 to 1.1 times, the thickness of the conductive pattern 20.

[0029] The upper surface 11 of the glass substrate 10 is opaque like frosted glass, and has fine irregularities. The upper surface 11 has a first region 13 in which a conductive pattern 20 is provided, and a second region 14 located between adjacent conductive patterns 20. The arithmetic mean roughness of the upper surface 11 is 0.20 μm or more in both the first region 13 and the second region 14. Therefore, the upper surface 11 is opaque in both the first region 13 and the second region 14. The surface roughness of the second region 14 of the upper surface 11 is about the same as that of the first region 13, or is larger due to damage caused by processing. The second region 14 may be colored due to damage caused by processing. The lower surface 12 of the glass substrate 10 is substantially smooth. The arithmetic mean roughness Ra of the lower surface 12 is, for example, 0.01 μm or less.

[0030] Since the upper surface 11 of the glass substrate 10 is frosted, the transmittance of light incident on the upper surface 11 is poor. For example, in a state where the conductive pattern 20 and the conductive film 30 are not provided, when red light (wavelength: 630 nm to 670 nm) is directly incident vertically on the first region 13 of the upper surface 11, the transmittance of the red light transmitted from the upper surface 11 to the lower surface 12 is 90% or less, may be 87% or less, or may be 85% or less. Even when the red light is directly incident vertically on the second region 14 of the upper surface 11, the transmittance of the red light transmitted from the upper surface 11 to the lower surface 12 is 90% or less, may be 87% or less, or may be 85% or less. The transmittance is the ratio of the intensity of the light emitted from the lower surface 12 to the intensity of the light incident on the upper surface 11.

[0031] The upper surface 11 of the glass substrate 10 has a shape in which the second region 14 is recessed in the -Z direction with respect to the first region 13. The second region 14 is formed deeper than the conductive pattern 20 at the boundary with the first region 13. In other words, the bottom of the second region 14 at the boundary with the first region 13 is located closer to the lower surface 12 of the glass substrate 10 than the conductive pattern 20.

[0032] [Manufacturing method] 3(a) to 3(d) are cross-sectional views illustrating a method for manufacturing the scale 100 according to the first embodiment. As illustrated in Fig. 3(a), first, a glass substrate 10 is prepared. At this stage, both the upper surface 11 and the lower surface 12 of the glass substrate 10 are smooth surfaces, and the arithmetic mean roughness Ra is, for example, 0.01 µm or less.

[0033] As shown in FIG. 3(b), the upper surface 11 of the glass substrate 10 is roughened to have a ground glass-like texture with fine irregularities. For example, the upper surface 11 is roughened to have a ground glass-like texture by blasting or chemical treatment using hydrofluoric acid or the like. By making the upper surface 11 into a ground glass-like texture, light incident on the upper surface 11 is diffusely reflected on the upper surface 11. As a result, the transmittance of the light incident on the upper surface 11, which is transmitted from the upper surface 11 to the lower surface 12, decreases. For example, the upper surface 11 is roughened to have an arithmetic mean roughness Ra of 0.20 μm or more to have a ground glass-like texture.

[0034] As illustrated in FIG. 3(c), the conductor film 22 is formed on the upper surface 11 of the glass substrate 10, and the conductor film 30 is formed on the lower surface 12. The conductor film 22 and the conductor film 30 are formed, for example, by electroless plating. The conductor film 22 and the conductor film 30 may be formed by forming a conductive film on the underlying conductive layer using electrolytic plating after forming an underlying conductive layer. It is preferable that the conductor film 22 and the conductor film 30 are formed (deposited) at the same time. In this case, the conductor film 22 and the conductor film 30 are formed of the same material and have approximately the same thickness.

[0035] As illustrated in Fig. 3(d), the conductor film 22 is patterned by laser processing using a laser beam 70 to form a plurality of conductor patterns 20. The laser processing is performed by pulsed laser processing using, for example, infrared (e.g., wavelength 1032 nm), green (e.g., wavelength 532 nm), or ultraviolet (e.g., wavelength 355 nm) laser beam 70. The pulsed laser processing is performed with, for example, a pulse width on the order of femtoseconds to picoseconds, and 0.1 to 10 J / cm. 2 By repeatedly irradiating the short pulse laser linearly at a high speed of, for example, 10 kHz to 5 MHz, the side surface of the conductor pattern 20 can be made into a flat tapered surface with an angle of about 60° to 80°.

[0036] Since the upper surface 11 of the glass substrate 10 is roughened to have a ground glass-like shape, the laser light 70 is diffusely reflected by the upper surface 11, and the energy is absorbed by the upper surface 11. Therefore, when the conductor film 22 is etched with the laser light 70 to form the conductor pattern 20, the second region 14 located between the adjacent conductor patterns 20 on the upper surface 11 of the glass substrate 10 is etched by the laser light 70, and maintains a state of high surface roughness when the etching depth reaches the upper surface 11. Therefore, the laser light 70 continues to be diffusely reflected by the upper surface 11, and the laser light 70 is prevented from transmitting from the upper surface 11 to the lower surface 12 and damaging the conductor film 30 provided on the lower surface 12.

[0037] In addition, processing conditions may be selected such that the upper surface 11 in the second region 14 is colored from opaque to black by irradiation with the laser light 70. Examples of processing conditions include a combination of various conditions such as laser intensity, pulse frequency, spot diameter, spot interval, focal depth, processing trajectory, and irradiation timing. If the upper surface 11 of the glass substrate 10 is not ground glass-like, the laser light 70 is irradiated in a state in which the smooth upper surface 11 of the glass substrate 10 is exposed by etching the conductive film 22, and therefore the laser light 70 may penetrate the glass substrate 10. However, by roughening the upper surface 11 of the glass substrate 10 in advance to a ground glass-like state, even if the upper surface 11 of the glass substrate 10 is exposed during etching with the laser light 70, the laser light 70 is prevented from penetrating the glass substrate 10 because the upper surface 11 is ground glass-like.

[0038] Moreover, the upper surface 11 of the glass substrate 10 is etched by irradiation with the laser light 70, so that the second region 14 is recessed from the first region 13. That is, the upper surface 11 becomes a recess in which the second region 14 is recessed from the first region 13. The inner surface of this recess may be a rough surface including coloring and unevenness, and may be tapered to totally reflect the laser light 70. For example, the angle between the bottom surface of the recess and the inner surface may be 30° or less. A periodic nano-sized uneven pattern (Laser-induced periodical surface structure: LIPSS) having the same wavelength as the laser light 70 may be formed on the tapered surface including the bottom surface of the recess and the conductor pattern 20. This uneven pattern is formed unintentionally and is not used as part of the scale. In addition, since the uneven pattern is nano-sized, the effect on the length measurement using the scale 100 is suppressed.

[0039] [Comparative Example 1] 4(a) to 4(c) are cross-sectional views illustrating a method for manufacturing a scale 500 according to Comparative Example 1. As illustrated in Fig. 4(a), a glass substrate 10 is prepared. Both an upper surface 11 and a lower surface 12 of the glass substrate 10 are smooth surfaces. As illustrated in Fig. 4(b), a conductor film 22 is formed on the upper surface 11 of the glass substrate 10, and a conductor film 30 is formed on the lower surface 12, without performing a process of roughening the upper surface 11 of the glass substrate 10 to make it like frosted glass.

[0040] As illustrated in FIG. 4(c), the conductor film 22 is patterned by laser processing using a laser beam 70 to form a plurality of conductor patterns 20. Since the upper surface 11 of the glass substrate 10 is not roughened and is a smooth surface, the laser beam 70 is not easily diffused by the upper surface 11. Therefore, the laser beam 70 is easily transmitted from the upper surface 11 to the lower surface 12. For example, the transmittance may be greater than 90% in a part of the second region 14. The laser beam 70 transmitted from the upper surface 11 to the lower surface 12 of the glass substrate 10 may cause damage such as scorch 72 on the conductor film 30 provided on the lower surface 12. If the scorch 72 is formed protruding from the lower surface of the conductor film 30, the posture of the glass substrate 10 may change in the subsequent patterning of the conductor film 22, and the focus of the laser beam 70 may be shifted, making it impossible to perform the patterning normally. In addition, when the scale 500 is placed on a flat mounting surface of the encoder device using an adhesive or the like, the scale 500 may tilt and become unusable as a scale. Furthermore, the scale 500 may become easily peeled off from the mounting surface of the encoder device.

[0041] In contrast, in the first embodiment, as shown in Fig. 3(b), the upper surface 11 of the glass substrate 10 is roughened to a ground glass state. Therefore, even when a plurality of conductor patterns 20 are formed on the upper surface 11 of the glass substrate 10 by laser processing using a laser beam 70 as shown in Fig. 3(d), the laser beam 70 is diffusely reflected by the upper surface 11, so that the influence of the laser beam 70 on the conductor film 30 formed on the lower surface 12 can be suppressed. Thus, damage to the conductor film 30 can be suppressed.

[0042] Thus, according to the first embodiment, the glass substrate 10 has a frosted upper surface 11. As a result, even when the conductor pattern 20 is formed by laser processing as described above, the conductor film 30 (formation) provided on the lower surface 12 of the glass substrate 10 is less likely to be damaged. In addition, since the conductor pattern 20 is provided on the frosted upper surface 11, the bonding area between the upper surface 11 and the conductor pattern 20 is increased, and the bonding strength of the conductor pattern 20 is improved.

[0043] In the first embodiment, as shown in FIG. 3(d), the conductor film 22 formed on the upper surface 11 of the glass substrate 10 is patterned by laser processing using a laser beam 70 to form the conductor pattern 20. Therefore, the upper surface 11 of the glass substrate 10 is also etched by the laser beam 70. As a result, the second region 14 of the upper surface 11 of the glass substrate 10 is recessed with respect to the first region 13, and is formed deeper than the conductor pattern 20 at the boundary with the first region 13. This prevents the conductor pattern 20 from being left at the bottom after it is formed. Therefore, disturbance in the current flowing through the conductor pattern 20 is prevented. From the viewpoint of suppressing disturbance of the current flowing through the conductive pattern 20, the distance L (see FIG. 2(b)) between the bottom of the second region 14 at the boundary with the first region 13 and the conductive pattern 20 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, while from the viewpoint of shortening the processing time, the distance L is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less. In addition, since the upper surface 11 of the glass substrate 10 is etched by the laser light 70, the second region 14 may have a larger surface roughness than the first region 13.

[0044] In the first embodiment, the conductor film 22 is formed on the upper surface 11 of the glass substrate 10, the conductor film 30 is formed on the lower surface 12, and then the conductor film 22 is patterned using laser processing to form the multiple conductor patterns 20. Since both the conductor film 22 and the conductor film 30 are formed, warping of the glass substrate 10 is suppressed, and the conductor film 22 can be well patterned using laser processing. In addition, for example, when the conductor film 22 is formed only on the upper surface 11, the conductor film 22 is patterned to form the multiple conductor patterns 20, and then the conductor film 30 is formed on the lower surface 12, an increase in manufacturing steps occurs. In contrast, the conductor film 22 and the conductor film 30 are simultaneously formed, and then the conductor film 22 is patterned to form the multiple conductor patterns 20, thereby suppressing an increase in manufacturing steps.

[0045] Second embodiment FIG. 5(a) is a plan view illustrating a scale 200 according to the second embodiment, and FIG. 5(b) is a cross-sectional view taken along line AA in FIG. 5(a). As illustrated in FIG. 5(a) and FIG. 5(b), in the scale 200, the lower surface 12 of the glass substrate 10 is opaque like ground glass, and fine irregularities are formed. For example, the lower surface 12 has a surface roughness similar to that of the upper surface 11 in the first region 13. The arithmetic mean roughness Ra of the upper surface 11 and the arithmetic mean roughness Ra of the lower surface 12 in the first region 13 are, for example, 0.20 μm or more, may be 0.25 μm or more, or may be 0.30 μm or more. The arithmetic mean roughness Ra of the lower surface 12 is, for example, 0.9 to 1.1 times, for example, 0.95 to 1.05 times, of the arithmetic mean roughness Ra of the upper surface 11 in the first region 13. The other configurations are the same as those of the scale 100 of the first embodiment, and therefore will not be described.

[0046] [Manufacturing method] In the scale 200 according to the second embodiment, in FIG. 3(b) of the first embodiment, both the upper surface 11 and the lower surface 12 of the glass substrate 10 are roughened to make both the upper surface 11 and the lower surface 12 like ground glass. The roughening treatment of the lower surface 12 is performed by the same method as the roughening treatment of the upper surface 11. To reduce the number of manufacturing steps, it is preferable to roughen the upper surface 11 and the lower surface 12 simultaneously (in one processing step). This gives the upper surface 11 and the lower surface 12 the same surface roughness. Thereafter, the same steps as those of FIG. 3(c) and FIG. 3(d) of the first embodiment are performed.

[0047] In the second embodiment, as in the first embodiment, the glass substrate 10 has a ground glass-like upper surface 11. Therefore, even when the conductor pattern 20 is formed on the upper surface 11 of the glass substrate 10 by laser processing using a laser beam 70, the conductor film 30 provided on the lower surface 12 of the glass substrate 10 is unlikely to be damaged.

[0048] In the second embodiment, the lower surface 12 of the glass substrate 10 is also ground glass. This makes it easier for the laser light 70 to be diffused even at the lower surface 12, making it difficult for the conductor film 30 provided on the lower surface 12 to be damaged. In addition, since the surface roughness of the lower surface 12 is large, the bonding area between the lower surface 12 and the conductor film 30 is increased, improving the bonding strength of the conductor film 30.

[0049] Third embodiment FIG. 6(a) is a plan view illustrating a scale 300 according to the third embodiment, and FIG. 6(b) is a cross-sectional view taken along line AA in FIG. 6(a). As illustrated in FIG. 6(a) and FIG. 6(b), in the scale 300, the lower surface 12 of the glass substrate 10 is also ground glass, as in the second embodiment. A resin film 80 is provided between the upper surface 11 of the glass substrate 10 and the conductive pattern 20, and a resin film 82 is provided between the lower surface 12 and the conductive film 30. The resin film 80 may function as an adhesive layer for bonding the glass substrate 10 and the conductive pattern 20, for example, and the resin film 82 may function as an adhesive layer for bonding the glass substrate 10 and the conductive film 30. The resin films 80 and 82 are formed of, for example, epoxy resin, acrylic resin, vinyl acetate resin, or the like. The other configurations are the same as those of the scale 100 of the first embodiment, and therefore will not be described.

[0050] [Manufacturing method] 7(a) to 7(d) are cross-sectional views illustrating a method for manufacturing a scale 300 according to the third embodiment. As illustrated in Fig. 7(a), first, a glass substrate 10 is prepared. At this stage, both an upper surface 11 and a lower surface 12 of the glass substrate 10 are smooth surfaces.

[0051] As illustrated in FIG. 7(b), similarly to the second embodiment, both the upper surface 11 and the lower surface 12 of the glass substrate 10 are subjected to a roughening treatment to make both the upper surface 11 and the lower surface 12 like ground glass.

[0052] As illustrated in FIG. 7(c), a metal foil is attached to the upper surface 11 of the glass substrate 10 using a resin film 80 as an adhesive layer, thereby forming a conductor film 22 on the upper surface 11. Similarly, a metal foil is attached to the lower surface 12 of the glass substrate 10 using a resin film 82 as an adhesive layer, thereby forming a conductor film 30 on the lower surface 12. The metal foil may be attached by a lamination method or a press processing method. The resin film 80 may be formed on the upper surface 11 of the glass substrate 10 by applying a resin or by attaching a sheet-like resin film. Alternatively, a metal foil coated with the resin film 80 may be attached to the upper surface 11 of the glass substrate 10. The same applies to the resin film 82.

[0053] 7(d), the conductor film 22 and the resin film 80 are patterned by laser processing using a laser beam 70 to form a plurality of conductor patterns 20. The laser processing is performed by the method shown in the first embodiment. Since the upper surface 11 of the glass substrate 10 is frosted glass, damage to the resin film 82 and the conductor film 30 provided on the lower surface 12 is suppressed, as in the first embodiment.

[0054] [Comparative Example 2] 8(a) to 8(c) are cross-sectional views illustrating a method for manufacturing a scale 600 according to Comparative Example 2. As illustrated in Fig. 8(a), a glass substrate 10 is prepared. Both an upper surface 11 and a lower surface 12 of the glass substrate 10 are smooth surfaces.

[0055] 8(b), a metal foil is attached to the upper surface 11 of the glass substrate 10 using a resin film 80 as an adhesive layer, thereby forming a conductor film 22 on the upper surface 11. A metal foil is attached to the lower surface 12 of the glass substrate 10 using a resin film 82 as an adhesive layer, thereby forming a conductor film 30 on the lower surface 12.

[0056] As illustrated in FIG. 8(c), the conductor film 22 and the resin film 80 are patterned by laser processing using a laser beam 70 to form a plurality of conductor patterns 20. Since the upper surface 11 of the glass substrate 10 is not roughened to have a ground glass-like appearance, the laser beam 70 transmitted from the upper surface 11 to the lower surface 12 of the glass substrate 10 may cause scorching 72 in the resin film 82 and the conductor film 30 provided on the lower surface 12, as in Comparative Example 1. In addition, a blister 74 may occur in the resin film 82. In this case, as in Comparative Example 1, the patterning of the conductor film 22 and the resin film 80 may not be performed normally, or the scale 600 may be placed on the encoder device at an angle, making it impossible to use the scale.

[0057] In contrast, in the third embodiment, the glass substrate 10 has a ground glass-like upper surface 11. Therefore, even when the conductor pattern 20 is formed on the upper surface 11 of the glass substrate 10 by laser processing using the laser light 70, as in the first embodiment, the influence of the laser light 70 on the resin film 82 and the conductor film 30 formed on the lower surface 12 can be suppressed, and the resin film 82 and the conductor film 30 can be made less likely to be damaged.

[0058] Moreover, in the third embodiment, a resin film 82 is provided between the lower surface 12 of the glass substrate 10 and the conductor film 30 (formation). In this case, as described in Comparative Example 2, if the upper surface 11 of the glass substrate 10 is not like frosted glass, the laser light 70 may cause blisters 74 in the resin film 82, making it impossible to use the resin film 82 as a scale. Therefore, when the resin film 82 is provided, it is preferable to make the upper surface 11 of the glass substrate 10 like frosted glass to suppress the effect of the laser light 70 on the resin film 82.

[0059] (Fourth embodiment) FIG. 9(a) is a plan view illustrating a scale 400 according to the fourth embodiment, and FIG. 9(b) is a cross-sectional view taken along line AA in FIG. 9(a). As illustrated in FIG. 9(a) and FIG. 9(b), the scale 400 has a ground glass bottom surface 12 of the glass substrate 10, as in the second embodiment. In the first to third embodiments, the entire second region 14 is recessed to the same extent as the first region 13 on the top surface 11 of the glass substrate 10. In the fourth embodiment, the adjacent portion 15 of the second region 14 adjacent to the first region 13 is recessed deeper than the central portion 16 located at the center in the X-axis direction. For example, the adjacent portion 15 may be recessed 5 μm or more, or 10 μm or more, from the central portion 16. The adjacent portion 15 may be a groove having a V-shaped cross section. The central portion 16 may be slightly recessed from the first region 13, or may not be recessed from the first region 13 and may have the same height as the first region 13. Furthermore, the adjacent portions 15 may have a surface roughness greater than that of the first region 13. The surface roughness of the central portion 16 may be approximately the same as or greater than that of the first region 13. The adjacent portions 15 and the central portion 16 may be colored black, as in the first embodiment. The other configurations are the same as those of the scale 100 in the first embodiment, and therefore will not be described.

[0060] [Manufacturing method] Figures 10(a) to 10(d) are cross-sectional views illustrating a method for manufacturing a scale 400 according to the fourth embodiment. First, as illustrated in Figures 10(a) and 10(b), the same steps as those illustrated in Figures 7(a) and 7(b) of the third embodiment are performed.

[0061] 10(c), a conductive paste is applied to the upper surface 11 of the glass substrate 10 by screen printing or the like, thereby forming a plurality of temporary conductor patterns 24 on the upper surface 11. A conductive paste is applied to the lower surface 12 of the glass substrate 10, thereby forming a conductor film 30 on the lower surface 12. By roughening the upper surface 11 to have a ground glass-like appearance, defects such as spreading of the conductive paste in the squeegee feed direction and / or smearing are suppressed.

[0062] When the temporary conductor pattern 24 is formed by applying a conductive paste, the side of the temporary conductor pattern 24 may have a tapered shape with a gentle angle. For this reason, as illustrated in FIG. 10(d), the edge portion of the temporary conductor pattern 24 is laser-processed using a laser beam 70 to form a conductor pattern 20 having a steep side. Since the upper surface 11 of the glass substrate 10 irradiated with the laser beam 70 is etched, the adjacent portion 15 of the second region 14 adjacent to the first region 13 is recessed relative to the first region 13. The adjacent portion 15 may have a larger surface roughness than the first region 13, or may become a groove with a V-shaped cross section. The central portion 16 of the second region 14 located at the center in the X-axis direction may be irradiated with the laser beam 70 for a short time and may be slightly recessed relative to the first region 13, or may be hardly irradiated with the laser beam 70 and may remain at the same height as the first region 13 without being recessed relative to the first region 13. When the laser light 70 is applied for only a short period of time, the surface roughness of the central portion 16 may be greater than the surface roughness of the first region 13, and when the laser light 70 is hardly applied, the surface roughness of the central portion 16 remains approximately the same as the surface roughness of the first region 13.

[0063] In the fourth embodiment, as in the first embodiment, the glass substrate 10 has a frosted upper surface 11. Therefore, even when the conductor pattern 20 is formed by irradiating the edge portion of the temporary conductor pattern 24 with the laser beam 70 to process the edge portion of the temporary conductor pattern 24, the influence of the laser beam 70 on the conductor film 30 formed on the lower surface 12 can be suppressed, and the conductor film 30 can be made less likely to be damaged.

[0064] Moreover, in the fourth embodiment, the conductor pattern 20 is formed by laser processing the edge portion of the temporary conductor pattern 24. Therefore, on the upper surface 11 of the glass substrate 10, the adjacent portion 15 of the second region 14 adjacent to the first region 13 is recessed with respect to the first region 13, and is formed deeper than the conductor pattern 20 at the boundary with the first region 13. This makes it possible to prevent the lower end portion from remaining in a tapered shape on the side surface of the conductor pattern 20, and to prevent disturbance in the current flowing through the conductor pattern 20.

[0065] (Experimental Example) 11(a) to 11(d) are examples of images of the upper surface 11 of the glass substrate 10 in Samples A to D taken by an optical microscope. In Sample A illustrated in FIG. 11(a), no roughening treatment was performed on the upper surface 11 and the lower surface 12 of the glass substrate 10, and the upper surface 11 and the lower surface 12 are smooth surfaces. The glass substrate 10 is made of soda-lime glass (the same is true for the glass substrates 10 in Samples B to D). The arithmetic mean roughness Ra and maximum height Rz of the upper surface 11 and the lower surface 12 were 0.00±0.00 μm. In addition, when red light was perpendicularly incident on the upper surface 11 of the glass substrate 10, the transmittance of the red light from the upper surface 11 to the lower surface 12 was 93%.

[0066] 11(b), the upper surface 11 and the lower surface 12 of the glass substrate 10 were subjected to a roughening treatment to make the upper surface 11 and the lower surface 12 like ground glass. The arithmetic mean roughness Ra of the upper surface 11 and the lower surface 12 was 0.05±0.02 μm, and the maximum height Rz was 0.48±0.17 μm. When red light was incident perpendicularly on the upper surface 11 of the glass substrate 10, the transmittance of the red light from the upper surface 11 to the lower surface 12 was 88%.

[0067] 11(c), the upper surface 11 and the lower surface 12 of the glass substrate 10 were subjected to a roughening treatment to make the upper surface 11 and the lower surface 12 like ground glass. The arithmetic mean roughness Ra of the upper surface 11 and the lower surface 12 was 0.30±0.14 μm, and the maximum height Rz was 1.43±0.36 μm. When red light was incident perpendicularly on the upper surface 11 of the glass substrate 10, the transmittance of the red light from the upper surface 11 to the lower surface 12 was 87%.

[0068] 11(d), the upper surface 11 and the lower surface 12 of the glass substrate 10 were subjected to a roughening treatment to make the upper surface 11 and the lower surface 12 like ground glass. The arithmetic mean roughness Ra of the upper surface 11 and the lower surface 12 was 0.72±0.08 μm, and the maximum height Rz was 2.10±0.47 μm. When red light was incident perpendicularly on the upper surface 11 of the glass substrate 10, the transmittance of the red light from the upper surface 11 to the lower surface 12 was 86%.

[0069] Using the glass substrates 10 of samples A to D, devices A and B shown in FIG. 12(a) and FIG. 12(b) were fabricated. In the device A illustrated in FIG. 12(a), a conductor film 22 is formed on the upper surface 11 of the glass substrate 10 via a resin film 80. A conductor film 30 is formed on the lower surface 12 of the glass substrate 10 via a resin film 82. A recess 76 is formed on the upper surface 11 of the glass substrate 10, penetrating the conductor film 22 and the resin film 80 and carving into a part of the glass substrate 10. The recess 76 was formed by laser processing using a green laser beam. For the laser processing, pulsed laser processing with a pulse width of about 20 ps and a power of about 10 W was used. The conductor films 22 and 30 are made of copper. The thickness of the glass substrate 10 is 1.1 mm, the thicknesses of the resin films 80 and 82 are 20 μm, and the thicknesses of the conductor films 22 and 30 are 12 μm. The width of the recess 76 is 250 μm, and the depth is 35 μm.

[0070] In the device B illustrated in FIG. 12(b), a conductor film 22 is formed on the upper surface 11 of the glass substrate 10. A conductor pattern 32 is formed on the lower surface 12 of the glass substrate 10. A recess 78 is formed on the upper surface 11 of the glass substrate 10, penetrating the conductor film 22 and carving into a part of the glass substrate 10. The recess 78 was formed by laser processing using a green laser beam. The laser processing was performed using pulsed laser processing with a pulse width of about 20 ps and a power of about 10 W. The conductor film 22 and the conductor pattern 32 are made of silver. The thickness of the glass substrate 10 is 1.1 mm, and the thickness of the conductor film 22 and the conductor pattern 32 is 12 μm. The width of the recess 78 is 250 μm, and the depth is 50 μm.

[0071] 13(a) to 13(d) are examples of optical microscope images of the upper and lower surfaces of device A fabricated using the glass substrates 10 of samples A to D. As illustrated in Fig. 13(a) to 13(d), damage occurs to the conductor film 30 on the lower surface of device A in samples A and B, but it was confirmed that damage to the conductor film 30 is suppressed in samples C and D.

[0072] 14(a) and 14(b) are examples of optical microscope images of the top and bottom surfaces of device B fabricated using glass substrates 10 of samples A and D. As illustrated in Fig. 14(a) and 14(b), damage occurs to conductor pattern 32 on the bottom surface of device A in sample A, but it was confirmed that damage to conductor pattern 32 is suppressed in sample D.

[0073] 13(a) to 14(b), under the illustrated laser processing conditions, it was confirmed that by setting the transmittance of red light from the upper surface 11 to the lower surface 12 of the glass substrate 10 to 87% or less, damage to the conductor film 30 or conductor pattern 32 provided on the lower surface 12 can be suppressed when the conductor film 22 is processed using laser processing. In addition, it was confirmed that when the upper surface 11 and the lower surface 12 are roughened to have a ground glass-like shape, the arithmetic mean roughness Ra of the upper surface 11 and the lower surface 12 is set to 0.16 μm or more, so that the transmittance of red light from the upper surface 11 to the lower surface 12 can be set to 87% or less. In this case, it was confirmed that the maximum height Rz of the upper surface 11 and the lower surface 12 is 1.07 μm or more. In addition, by setting different laser processing conditions in terms of parameters such as the wavelength, power, and pulse density of the laser light, the transmittance and degree of roughening of the glass substrate 10 must be further increased in order to damage the conductor film 30, etc., or conversely, even if the transmittance and degree of roughening are small, no damage may be caused to the conductor film 30, etc.

[0074] In the above embodiment, the case where the conductive film 30 is a solid film formed on the lower surface 12 of the glass substrate 10 has been described as an example, but the present invention is not limited to this case. The formed object formed on the lower surface 12 may be a solid film other than a conductive film, a patterned film, or an element constituting a circuit such as a sensor element.

[0075] In the above embodiment, the electromagnetic induction type encoder 1000 is taken as an example, but other types such as a photoelectric encoder may also be used. Also, the scale used in a linear encoder is taken as an example, but a scale used in a rotary encoder or a scale used in other encoders or sensors such as an arc encoder may also be used.

[0076] Although FIG. 1(a) shows an example in which the electromagnetic induction encoder 1000 includes the scale 100 of the first embodiment, the encoder 1000 may include the scales of the second to fourth embodiments.

[0077] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to such specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0078] 10 Glass substrate 11 Top side 12 Bottom side 13 First area 14 Second area 15 Adjacent parts 16 Central part 20 Conductor Pattern 22 Conductor Film 24 Temporary Conductor Pattern 30 Conductive film (formation) 32 Conductor Pattern 40 Detection head 42 Transmitting coil 44 Receiver coil 50 Transmission signal generator 60 Displacement measurement section 70 Laser Light 76, 78 Recess 80 Resin Film 82 Resin Film 100, 200, 300, 400, 500, 600 scale 1000 Electromagnetic Inductive Encoder

Claims

1. a glass substrate having a frosted upper surface; a plurality of conductor patterns arranged at predetermined intervals on the upper surface of the glass substrate; and a formation provided on the lower surface of the glass substrate.

2. the upper surface of the glass substrate has a first region in which the plurality of conductor patterns are provided and a second region located between the plurality of conductor patterns; At least a portion of the second region adjacent to the first region is recessed with respect to the first region, 2. The scale according to claim 1, wherein the second region is formed deeper than the plurality of conductor patterns at the boundary with the first region.

3. 3. The scale according to claim 2, wherein the bottom surface of at least a portion of the second region adjacent to the first region has a surface roughness greater than that of the first region.

4. 3. The scale according to claim 1, wherein the lower surface of the glass substrate is ground glass.

5. a resin film provided between the lower surface of the glass substrate and the formation, 3. The scale according to claim 1, wherein the formation is a conductive film.

6. An encoder comprising the scale according to claim 1 or 2.

7. Roughening the top surface of the glass substrate to a ground glass-like texture; forming a formation on a lower surface of the glass substrate; and forming a plurality of conductor patterns arranged at predetermined intervals on the top surface of the glass substrate by laser processing after roughening the top surface of the glass substrate to a frosted glass like shape and forming the formation.

8. A step of forming a conductor film on the upper surface of the glass substrate after roughening the upper surface of the glass substrate to a ground glass state, 8. The method for manufacturing a scale according to claim 7, wherein the step of forming the plurality of conductor patterns comprises forming the plurality of conductor patterns by patterning the conductor film by laser processing.

9. The method includes a step of roughening the upper surface of the glass substrate to a ground glass state, and then forming a plurality of temporary conductor patterns on the upper surface of the glass substrate; 8. The method for manufacturing a scale according to claim 7, wherein the step of forming the plurality of conductor patterns comprises forming the plurality of conductor patterns by processing edge portions of the plurality of temporary conductor patterns by the laser processing.

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