A processing method for glass reflective code disc

Abstract

The present invention provides a method for processing a glass reflective code disc, and relates to the technical field of processing encoder code discs. In order to make the two sides of the glass code disc have different optical properties and patterns of specific sizes, the present invention adopts a method of first cutting, then coating, and then splitting for secondary coating, so as to achieve the purpose of reducing secondary photolithography, thereby making the processing technology of the glass code disc simpler; at the same time, since the glass code disc is still on a glass substrate that has not been cut and disassembled, its secondary coating is easier to operate; the processing method provided by the present invention does not require hanging edges, and can achieve full-area coating of the glass code disc. The processing method provided by the present invention is simple and easy to operate, and has low cost.

Description

Technical Field

[0001] The invention relates to the technical field of encoder code disc processing, and in particular to a method for processing a glass reflective code disc. Background Art

[0002] As an angle and speed measurement sensor, the encoder uses a chip to read the angle of the rotating code disk to measure the angle of the main shaft. Usually, it is a transmissive reading, that is, the light source and the reading chip are located on both sides of the code disk. However, with the development of chip technology and the compression of encoder volume, there is a demand for the light source and the chip to be on the same side, and the code disk has also changed from a simple transmissive code disk (composed of light-shielding area and light-transmitting area graphics) to a reflective code disk (composed of light-reflecting area and light-absorbing area graphics).

[0003] Since the glass code disc has a high light transmittance, when the glass code disc is installed on a metal base, the light absorption area has a large reflectivity, which affects the signal sensing. Therefore, a light shielding layer needs to be plated on the glass code disc to reduce light reflection. Such a glass reflective code disc needs both a low-reflection film layer and a high-reflection signal film layer.

[0004] At present, one of the common processing technologies is to first coat a low-reflection film on one side of the glass code disc, then photolithograph it into an image, and then coat a high-reflection film on the other side of the glass code disc, and then photolithograph it again to form a high-reflection signal pattern on the other side of the glass code disc; the other is to first coat a high-reflection film on one side of the code disc through photolithography, cut it into small finished products, and then coat the other side of the code disc with a low-reflection film through secondary coating. This process cannot be coated when the diameter of the code disc is smaller than 5mm, and the coating of the code disc needs to be edged, the film layer cannot completely cover the code disc, and multiple processes such as small particle cleaning and small particle inspection before and after coating are required. The smaller the size of the code disc, the greater the workload. Both processing technologies are relatively complex and costly. Summary of the invention

[0005] The object of the present invention is to provide a method for processing a glass reflective code disk. The processing method provided by the present invention is simple and easy to operate, has low cost, and can prepare a glass code disk of any diameter.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for processing a glass reflective code disk, comprising the following steps:

[0008] (1) coating a high reflective film on surface A of a glass substrate;

[0009] (2) coating photoresist on the surface of the high-reflection film, attaching a mask having a target pattern to the coated glass substrate, and exposing it under an exposure machine;

[0010] (3) developing the exposed glass substrate in a developer;

[0011] (4) placing the developed material into an etching solution for etching to obtain a glass substrate containing a target pattern; the target pattern is between the inner ring and the outer ring of the code disk;

[0012] (5) Cut off the inner circle of the pattern and punch holes in the outer circle of the pattern;

[0013] (6) coating a low-reflection film on surface B of the glass substrate;

[0014] (7) The glass reflective code disk is obtained by using a splitting machine to split the glass.

[0015] Preferably, before plating the high reflective film in step (1), the process further comprises: cleaning the glass substrate.

[0016] Preferably, the coating method of the high reflective film in step (1) includes vacuum evaporation coating, magnetron sputtering coating or chemical vapor deposition.

[0017] Preferably, the photoresist in step (2) is a positive photoresist.

[0018] Preferably, the developer in step (3) is a sodium hydroxide solution.

[0019] Preferably, the etching solution in step (4) is an aqueous solution of ammonium cerium nitrate and glacial acetic acid.

[0020] Preferably, the device used for the cutting in step (5) is a nanosecond laser cutting machine; and the device used for the punching is a picosecond laser cutting machine.

[0021] Preferably, the coating method of the low-reflection film in step (6) includes vacuum evaporation coating, magnetron sputtering coating or chemical vapor deposition.

[0022] Preferably, before plating the low-reflection film in step (6), the process further includes: sticking a high-temperature adhesive tape on the mark point of the glass substrate.

[0023] Preferably, the diameter of the glass reflective code disk is 3 to 150 mm.

[0024] The present invention provides a processing method for a glass reflective code disk. The present invention coats a low-reflection film on the entire surface B of a glass substrate. A large size makes it easier to coat the film. In order to avoid the problem that the entire surface cannot be cut after coating, the inner hole is first cut off before coating the low-reflection film, and holes are punched in the outer circle at the same time. In order to make the two sides of the glass code disk have different optical properties and patterns with specific sizes, the present invention adopts a method of first cutting, then coating, and then splitting for secondary coating (coating a low-reflection film on the B surface of the glass substrate) to achieve the purpose of reducing secondary photolithography, thereby making the processing technology of the glass code disk simpler; at the same time, because the glass code disk is still on the glass substrate that has not been cut and disassembled, its secondary coating is easier to operate, and there is no requirement for the diameter of the code disk. The diameter size mainly depends on the production capacity of the production line; the processing method provided by the present invention does not require hanging edges, and can achieve full-area coating of the glass code disk. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process flow chart for preparing a glass reflective code disk according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention provides a method for processing a glass reflective code disk, comprising the following steps:

[0027] (1) coating a high reflective film on surface A of a glass substrate;

[0028] (2) coating photoresist on the surface of the high-reflection film, attaching a mask having a target pattern to the coated glass substrate, and exposing it under an exposure machine;

[0029] (3) developing the exposed glass substrate in a developer;

[0030] (4) placing the developed material into an etching solution for etching to obtain a glass substrate containing a target pattern; the target pattern is between the inner ring and the outer ring of the code disk;

[0031] (5) Cut off the inner circle of the pattern and punch holes in the outer circle of the pattern;

[0032] (6) coating a low-reflection film on surface B of the glass substrate;

[0033] (7) The glass reflective code disk is obtained by using a splitting machine to split the glass.

[0034] The present invention coats a high-reflection film on surface A of a glass substrate. In the present invention, before coating the high-reflection film, it is preferably further included: cleaning the glass substrate. The present invention ensures that the coated surface of the glass substrate is clean by cleaning. The present invention has no special requirements on the material and size of the glass substrate, which is subject to the requirements of the customer. In the present invention, the cleaning is preferably ultrasonic cleaning; the cleaning agent used for the cleaning preferably includes an alkaline cleaning agent with a pH range of 11 to 12, isopropyl alcohol and deionized water. In the present invention, the cleaning preferably includes: washing the glass substrate with an alkaline cleaning agent, washing with deionized water and evaporating isopropyl alcohol in sequence.

[0035] In the present invention, the coating method of the high reflective film preferably includes vacuum evaporation coating, magnetron sputtering coating or chemical vapor deposition, and more preferably magnetron sputtering coating. In the present invention, the reflectivity of the high reflective film is preferably above 60%; the material of the high reflective film is preferably chromium, aluminum, copper or platinum; the thickness of the high reflective film is preferably 20 to 1000 nm.

[0036] After coating the high-reflection film, the present invention coats photoresist on the surface of the high-reflection film, and a mask having a target pattern is attached to the glass substrate after the coating, and is exposed under an exposure machine. In the present invention, the photoresist is preferably a positive photoresist. In the present invention, the coating thickness of the photoresist is preferably 50μm~1mm, and more preferably 0.2mm. In the present invention, after coating the photoresist, baking is preferably performed to obtain the glass substrate after the coating. In the present invention, the baking temperature is preferably 80~120℃, and more preferably 95℃; the baking time is preferably 20~60min, and more preferably 40min. In the present invention, the exposure is preferably ultraviolet light irradiation; the wavelength of the ultraviolet light is preferably 365nm; the exposure time is preferably 5~20s, and more preferably 7s. The mask having the target pattern is the carrier of the original pattern in the exposure process, and the information of these patterns is transferred to the glass substrate through the exposure process.

[0037] In the present invention, the photoresist can be turned into a soluble substance in a corresponding developer after being irradiated with 365nm ultraviolet light, and then after being etched by an etching solution, the film without the photoresist coating is etched away, and finally the desired optical pattern can be stored on the glass substrate.

[0038] After exposure, the present invention develops the exposed glass substrate in a developer. In the present invention, the developer is preferably a sodium hydroxide solution. In the present invention, the mass concentration of the sodium hydroxide solution is preferably 0.5-2%, more preferably 1%. In the present invention, the development temperature is preferably room temperature; the development time is preferably 15-30 seconds, more preferably 20 seconds.

[0039] After development, the present invention places the developed material into an etching solution for etching to obtain a glass substrate containing a target pattern. In the present invention, the etching solution is preferably an aqueous solution of ammonium cerium nitrate and glacial acetic acid. In the present invention, the concentration of ammonium cerium nitrate in the etching solution is preferably 50 to 300 g / L, more preferably 200 g / L; the concentration of glacial acetic acid is preferably 20 to 60 g / L, more preferably 36 to 37 g / L. In the present invention, the etching temperature is preferably 15 to 35°C; the etching time is preferably 30 to 150 s, more preferably 60 s.

[0040] In the present invention, the target pattern is between the inner circle and the outer circle, and is preferably composed of a plurality of sector-shaped code channels.

[0041] After obtaining the glass substrate containing the target pattern, the present invention cuts off the inner circle of the pattern and punches holes in the outer circle of the pattern. In the present invention, the device used for cutting the inner circle is preferably a nanosecond laser cutting machine; the device used for punching holes is preferably a picosecond laser cutting machine. In the present invention, the nanosecond laser cutting machine mainly generates conduction band electrons after the material absorbs photons through nanosecond laser radiation photons. The electrons emit phonons during the movement of the material and transfer the absorbed energy to the lattice. The lattice undergoes energy deposition to cause the material to melt or mechanically damage, thereby achieving high-quality micro-machining; the picosecond laser cutting machine punches holes through electronic pulses, and then performs splitting to achieve cutting. The splitting process is energy heating, thermal expansion and contraction, so that the holes on the cutting path collapse. If the inner hole is cut by picoseconds, there is a risk of the inner hole bursting due to thermal expansion and excessive energy, so nanoseconds are generally used to cut the inner hole. After the inner hole is cut off, there is no risk of bursting when the outer hole is cut by picoseconds. At the same time, the outer ring is cut by picoseconds to achieve zero edge collapse of the code disk, thereby improving the quality of the code disk.

[0042] The present invention coats a low-reflection film on the B surface of the glass substrate. In the present invention, the A surface and the B surface of the glass substrate refer to two opposite surfaces of the glass substrate. In the present invention, the coating method of the low-reflection film preferably includes vacuum evaporation coating, magnetron sputtering coating or chemical vapor deposition, and more preferably magnetron sputtering coating. In the present invention, the reflectivity of the low-reflection film is preferably less than 10%; the reflectivity of the low-reflection film is preferably lower than the reflectivity of the high-reflection film by more than 50%; the material of the low-reflection film is preferably chromium, aluminum, copper or platinum; the thickness of the low-reflection film is preferably 20 to 1000nm.

[0043] After the low-reflection film is plated, the present invention is split by a splitting machine to obtain a glass reflective code disk. In the present invention, the diameter of the glass reflective code disk is preferably 3 to 150 mm, more preferably 25 to 100 mm. In the present invention, the diameter of the glass reflective code disk refers to the outer ring diameter of the glass reflective code disk.

[0044] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] like Figure 1 As shown in the flow chart, a glass substrate with a length, width and thickness of 151.8 mm×151.8 mm×1.0 mm is selected, and the glass substrate is washed with an alkaline cleaning agent with a pH range of 11 to 12, washed with deionized water and evaporated with isopropanol in sequence, and a pure chromium film is plated on the A side by a magnetron sputtering coating machine. After the film performance meets the requirements of Olympus reflectivity greater than 60%, a layer of positive photoresist is evenly coated on the chromium film by a coating device, and the thickness is 0.2 mm. After baking at 95°C for 40 minutes, a layer with a target pattern ( The mask plate with a circle pattern composed of sectors) is closely attached to the glue surface, placed in an exposure machine, exposed to 365nm ultraviolet light for 7s, and then the exposed product is placed in a sodium hydroxide aqueous solution with a mass concentration of 1% for development at room temperature for 20s, and then placed in an etching solution composed of ammonium cerium nitrate, glacial acetic acid and water (the components of the etching solution are 600g of ammonium cerium nitrate, 110g of glacial acetic acid, and 3L of water) for etching for 60s to make a glass substrate with a target pattern, and the photoresist is removed from the qualified product to obtain a large reflective glass code disk plate;

[0047] The inner hole of the code disc is cut out by a nanosecond laser cutting machine, and then a hole is punched in the outer ring of the code disc by a p-second laser cutting machine without splitting, so as to obtain a large glass code disc plate with the inner hole cut out;

[0048] A clean cover sheet is used to cover the A side of the glass code disc plate, and a high-temperature tape is attached to the mark of the glass code disc plate. A chromium oxide film is plated on the B side by a magnetron sputtering coating machine. After the film performance meets the requirements of Olympus reflectivity less than 5%, the high-temperature tape is torn off, and the outer ring of the code disc is cut by a splitting machine to obtain a glass reflective code disc. The inner hole diameter of the glass reflective code disc is 14.3 mm, and the outer ring diameter is 24 mm.

[0049] Comparative Example 1

[0050] After the glass substrate is ultrasonically cleaned with a professional cleaning agent, a chromium oxide film is plated on the B side through a magnetron sputtering coating machine. After the film performance is tested by an Olympus reflectivity tester and the reflectivity is less than 10%, a layer of positive photoresist is evenly coated on the film layer through a coating device, and the mask with the target pattern is tightly attached to the adhesive surface, placed in an exposure machine for exposure for 7 seconds, and the exposure wavelength is 365nm. Then, the exposed product is placed in a sodium hydroxide aqueous solution with a mass concentration of 1% and developed at room temperature for 20 seconds, and then placed in an etching solution composed of ammonium cerium nitrate and acetic acid (the components of the etching solution are 600g ammonium cerium nitrate, 110g glacial acetic acid, and 3L water) The substrate with a circle on the back is made by etching in the middle, and then the qualified products are debonded and cleaned, and then a pure chromium film is plated on the A side by a magnetron sputtering coating machine. After the film performance is tested by an Olympus reflectivity tester and the reflectivity is greater than 60%, a layer of positive photoresist is evenly coated on the film layer through a uniform coating device, and a mask with another target pattern is tightly fitted to the glue surface. When fitting, the circle pattern on the B side is aligned with the pattern on the A side. After exposure, development, etching and debonding, a substrate with another pattern on the A side is obtained. Finally, the inner diameter is cut off by a nanosecond laser cutting machine, and the outer circle is cut off by a P-second laser cutting machine to obtain a glass reflective code disk.

[0051] It can be seen from the preparation processes of the embodiments and comparative examples that the present invention adopts the method of first cutting, then coating and finally splitting for secondary coating, which reduces the secondary photolithography and makes the processing technology of the glass code disk more concise.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for processing a glass reflective code disc, It is characterized in that The following steps are involved: (1) coating a high-reflection film on surface A of a glass substrate; the reflectivity of the high-reflection film is greater than 60%; (2) coating photoresist on the surface of the high-reflection film, attaching a mask having a target pattern to the coated glass substrate, and exposing the mask to light under an exposure machine; (3) developing the exposed glass substrate in a developer; (4) placing the developed material into an etching solution for etching to obtain a glass substrate containing a target pattern; the target pattern is between the inner ring and the outer ring of the code disk; (5) Cut off the inner circle of the pattern and punch holes in the outer circle of the pattern; (6) coating a low-reflection film on surface B of the glass substrate; the reflectivity of the low-reflection film is less than 10%; (7) Splitting the glass through a splitting machine to obtain a glass reflective code disk; The A surface and the B surface of the glass substrate refer to two opposite surfaces of the glass substrate.

2. The processing method according to claim 1, It is characterized in that Before plating the high reflective film in step (1), the method further comprises: cleaning the glass substrate.

3. The processing method according to claim 1, It is characterized in that The coating method of the high reflective film in step (1) includes vacuum evaporation coating, magnetron sputtering coating or chemical vapor deposition.

4. The processing method according to claim 1, It is characterized in that The photoresist in step (2) is a positive photoresist.

5. The processing method according to claim 1, It is characterized in that The developer in step (3) is a sodium hydroxide solution.

6. The processing method according to claim 1, It is characterized in that The etching solution in step (4) is an aqueous solution of ammonium cerium nitrate and glacial acetic acid.

7. The processing method according to claim 1, It is characterized in that The device used for the cutting in step (5) is a nanosecond laser cutting machine; the device used for the punching is a picosecond laser cutting machine.

8. The processing method according to claim 1, It is characterized in that The coating method of the low-reflection film in step (6) includes vacuum evaporation coating, magnetron sputtering coating or chemical vapor deposition.

9. The processing method according to claim 1 or 8, It is characterized in that Before plating the low-reflection film in step (6), the process also includes: sticking a high-temperature adhesive tape on the mark point of the glass substrate.

10. The processing method according to claim 1, It is characterized in that The diameter of the glass reflective code disk is 3-150 mm.

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