TW201412456A - Method for polishing board-like body, and apparatus for polishing board-like body - Google Patents

Abstract

This method for polishing a board-like body is provided with: a planarity measuring step wherein planarity of a board-like body surface to be polished is measured; and a polishing step wherein the surface of which the planarity has been measured is polished by means of a polishing tool by relatively pressing and relatively rotating the surface and the polishing tool to each other. Polishing conditions in the polishing step are changed on the basis of the planarity of the surface, said planarity having been measured in the planarity measuring step.

Description

Plate-like body grinding method and plate-shaped body polishing device

The present invention relates to a method of polishing a plate-shaped body and a polishing apparatus for a plate-shaped body.

As an example of a method for producing a glass plate for an FPD (FLAT PANEL DISPLAY) such as a liquid crystal display, a floating manufacturing method using a molding method called a floating method is known. The manufacturing method includes a forming step of supplying molten glass to a surface of molten metal retained in a floating kiln to form a strip-shaped glass plate, and cutting and chamfering steps to cut the strip-shaped glass sheet into a specific size. a rectangular glass plate for grinding a peripheral portion of the cut rectangular glass plate; and a polishing step for removing minute irregularities or undulations of the polished surface of the rectangular glass plate by a polishing device; and In the step of cleaning the polished rectangular glass plate and measuring the flatness of the surface to be polished (the deformation of the surface height due to minute convex or concave undulations or the like existing on the surface of the surface to be polished, defined as undulation The ratio of height to undulation spacing (undulation height / undulation spacing)). By the above steps, the rectangular glass plate is made into a glass plate suitable for a FPD glass plate having a thickness of 0.2 to 1.5 mm and a high flatness.

Patent Document 1 discloses a batch type polishing apparatus for a glass plate for FPD. The polishing apparatus of Patent Document 1 includes a film body including an adsorption sheet that adsorbs and holds a glass plate, and a film frame in which the adsorption sheet is stretched. According to the polishing apparatus, a pressurized fluid is supplied between the membrane body and the carrier on which the membrane body is attached, and the pressure of the pressurized fluid is pressed against the surface to be polished of the glass sheet adsorbed on the adsorption sheet to the polishing pad (grinding) And grinding the glass plate and the polishing pad relative to each other (rotation and/or revolution) mill.

Further, in the above inspection step, it is checked whether the flatness of the surface to be polished of the polished glass plate is within the specification value of the glass plate for FPD. This flatness inspection is performed using, for example, a known flatness measuring apparatus disclosed in Patent Document 2.

The flatness measuring apparatus of Patent Document 2 includes a light source that irradiates a pattern having a periodic light and darkness to a glass plate, a light receiving mechanism that receives a pattern of a pattern or reflection transmitted through the glass plate, and a flatness measuring mechanism that is based on light receiving The flatness of the polished surface of the glass sheet is calculated by the deviation of the light-dark period of the image from the light-dark period of the pattern of the light source. Further, the flatness measuring means includes: an averaging means for averaging the brightness of the area of the light receiving image of a size corresponding to the light and dark period of the pattern irradiated to the glass sheet; and a processing means for outputting the averaging means The signal is averaged to output a signal for the deformation portion and the amount of deformation of the surface shape of the specific glass plate.

According to the flatness measuring apparatus of Patent Document 2, a pattern having a periodic light and dark is irradiated onto a glass plate and receives a pattern of pattern or reflection transmitted through the glass plate, and in order to detect a deviation of a light-dark cycle of the light-receiving image (relative to irradiation to The deviation of the light-dark period of the pattern on the glass plate is averaged, and the brightness of the area of the light-receiving image of the size corresponding to the light-dark period of the pattern irradiated to the glass plate is averaged, and the glass plate is calculated based on the averaged signal. The flatness of the surface to be polished.

Advanced technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-122351

Patent Document 2: Japanese Patent No. 3411829

In the prior batch type grinding apparatus, in order to make the flatness within the specification value, in the grinding step, the actual grinding amount is set more than assumed to be satisfied for the following reasons. Grinding is performed by the amount of polishing of the optimum polishing amount of the flatness of the specification value.

That is, the reason is that, for the glass plate before polishing, the flatness of the polished surface of each of the glass plates is different, so when the glass plate is polished under the same polishing conditions, there is a possibility that all the glass plates cannot be The flatness of the abrasive surface is within the specification. For this reason, the actual amount of polishing is set more than the assumed amount of polishing, so that even if the flatness of each of the glass sheets is different, the flatness of the surface to be polished of all the glass sheets can be made into the specification value.

In other words, in the case where the glass plate having a low flatness is polished by the polishing conditions for achieving the optimum polishing amount for the glass plate having a high degree of flatness, the amount of polishing is small, and the flatness deviates from the specification value. Therefore, not only the glass plate having a lower flatness but also the glass plate having a lower flatness is polished in order to achieve the optimum polishing amount for the glass plate having a lower flatness, and the glass plate having a higher flatness is also ground, thereby making all the glass plates The flatness of the surface to be polished is within the specification value.

However, in the above-described polishing method, the glass plate having a high flatness is polished at a polishing amount of more than necessary, so that the polishing time is prolonged and the production efficiency of the glass plate is lowered.

The present invention has been made in view of such a problem, and an object thereof is to provide a polishing method for a plate-shaped body and a polishing apparatus for a plate-shaped body which can improve the production efficiency of a plate-shaped body.

In order to achieve the above object, the present invention provides a method of polishing a plate-shaped body, comprising: a flatness measuring step of measuring a flatness of a surface to be polished of a plate-like body; and a grinding step for determining a flatness of the flatness Grinding the surface of the plate-shaped body to be polished, relatively pressing the surface to be polished of the plate-shaped body and the polishing tool, and rotating the surface of the plate-shaped body relative to the polishing tool to rotate by the polishing tool The surface to be polished is polished; and the polishing conditions of the polishing step are changed based on the flatness of the surface to be polished of the plate-like body measured in the flatness measuring step.

In order to achieve the above object, the present invention provides a plate-like body polishing apparatus, which comprises a flatness measuring mechanism that measures a flatness of a surface to be polished of a plate-shaped body, and a polishing mechanism that polishes a surface to be polished of the flat body having a measured flatness and relatively presses the plate a surface to be polished and a polishing tool, wherein the polished surface of the plate-shaped body is rotated relative to the polishing tool to be polished by the polishing tool; and a control mechanism is determined based on the flatness measuring mechanism The flatness of the surface to be polished of the plate-like body changes the polishing conditions of the polishing mechanism.

The present invention is directed to a polishing method and a polishing apparatus for relatively pressing a surface to be polished of a plate-shaped body and a polishing tool, and rotating the surface to be polished of the plate-shaped body and the polishing tool. The ground surface of the plate-like body is ground by grinding. In other words, the present invention is directed to a batch type polishing method and a polishing apparatus for polishing a sheet-like body disclosed in Patent Document 1 by one polishing apparatus. In other words, the polishing method and the polishing apparatus of the present invention are not intended to be the continuous polishing method and the polishing apparatus disclosed in, for example, Japanese Laid-Open Patent Publication No. 2007-190657, and the International Publication No. 2011/074616A1. In the following continuous polishing method and polishing apparatus, a plurality of polishing tools are arranged in the conveying direction of the plate-like body, and a plurality of plate-shaped bodies are continuously conveyed at a constant speed, and are slowly ground by a plurality of polishing tools. The polished surface of the plate-shaped body. In addition, after the one plate-shaped body is roughly polished by the first rough polishing tool, the polishing method and the polishing device for performing the fine polishing by the second polishing tool are batch type, and therefore The invention is targeted.

According to the invention, first, the flatness of the surface to be polished of the plate-shaped body is measured for each of the plate-shaped bodies by the flatness measuring means before the polishing of the plate-shaped body. Next, the control means calculates an optimum polishing amount corresponding to the flatness for each of the plate-like bodies, calculates an optimum polishing condition corresponding to the optimum polishing amount, and changes the polishing condition of the polishing mechanism to The above best grinding conditions. Therefore, the polished surface of the plate-shaped body is polished by the optimum polishing conditions corresponding to the flatness. Thereby, according to the present invention, the production efficiency of the plate-like body is improved as compared with the prior art polishing apparatus.

The above-mentioned optimum polishing amount is of course the amount of polishing for setting the flatness within the specification value, and is the polishing amount set as follows: the peak value (average value) of the distribution of the flatness of the surface to be polished after polishing The peak value of the distribution of the flatness using the previous grinding method is closer to the specification value. Thereby, the polishing time of the present invention as one of the polishing conditions is shortened as compared with the prior art, so that the production efficiency of the plate-shaped body is improved.

Moreover, the polishing conditions mentioned in the present invention mean that the polishing time is a typical polishing condition when the polishing pressure is fixed. Since the present invention is a batch type, the polishing time of a plurality of plate-like bodies having different flatness (feedforward control) can be changed for each plate-like body. On the other hand, in the above-described continuous polishing apparatus, it is difficult to control the polishing time for each of a plurality of plate-like bodies having different flatness. That is, the reason is that the continuous polishing apparatus is a device that transports a plate-shaped body at a fixed speed, in other words, the continuous polishing device is a device that fixes the polishing time.

Further, the polishing conditions are not limited to the polishing time, but also include other polishing conditions such as the polishing pressure of the polishing tool with respect to the surface to be polished of the plate-like body and the relative rotation of the polishing tool and the plate-like body. The grinding time is changed for each flatness. The reason for this is that the polishing pressure and the number of rotations are fixed and the polishing time is changed only from the viewpoint of the device configuration and the control system construction, and the polishing pressure is changed for each plate-shaped body. The above number of rotations is easier.

Moreover, in the polishing method and the polishing apparatus including the above-described rough polishing tool and fine polishing tool, it is only necessary to control the polishing time of at least one of the rough polishing tool and the polishing polishing tool. For example, when the measured flatness largely deviates from the flatness of the specification, the polishing time of the rough abrasive is changed for a long time. Further, when the measured flatness is extremely deviated from the flatness of the specification, the polishing time of the rough polishing tool is changed to an extremely short time, and the polishing time of the polishing tool is also changed to a short time. That is, it is preferable to change the cumulative polishing time of the roughing tool and the finishing tool so as to be the shortest polishing time based on the measured flatness.

Preferably, one aspect of the polishing method of the present invention includes a flatness re-measurement step in the subsequent step of the polishing step, wherein the flatness re-measurement step is performed on the plate-like body polished in the grinding step. The flatness of the surface to be polished is measured again, and the polishing conditions of the polishing step are further changed based on the flatness of the surface to be polished of the plate-like body measured in the flatness re-measurement step.

Preferably, the aspect of the polishing apparatus of the present invention includes a flatness re-measurement mechanism for flattening the surface to be polished of the plate-shaped body which has been polished by the polishing mechanism. In the re-measurement, the control means further changes the polishing conditions of the polishing means based on the flatness of the surface to be polished of the plate-shaped body measured by the flatness re-measurement means.

According to an aspect of the present invention, polishing conditions such as polishing time are further changed (feedback control) based on the flatness of the surface to be polished after polishing measured by the flatness re-measurement mechanism. That is, in one aspect of the present invention, the polishing time which is changed based on the flatness of the surface to be polished before polishing is finely adjusted based on the flatness of the surface to be polished after polishing, so that it is possible to produce a uniform unevenness in flatness. Quality plate.

Further, in the present invention, depending on the state of the surface of the plate-like body before polishing, there may be a plate-like body in which the flatness of the surface to be polished after polishing is deviated from the specification value, but it is preferable to set the optimum in the following manner. The amount of polishing: The frequency of the plate-like body deviating from the specification value is 0.5% or less of the entire batch (parent group), preferably 0.3% or less. Preferably, the plate-like system deviating from the specification value is detected by the flatness re-measurement mechanism, but thereafter re-grinding is performed by a grinding mechanism whose polishing time is finely adjusted. Thereby, the plate-shaped body which deviates from the specification value can be made into the specification value. Further, in order to increase the production efficiency of the plate-like body, another polishing mechanism may be provided after the flatness re-measurement mechanism, and the plate-shaped body which is deviated from the specification value may be re-polished by the other polishing means to be flattened. The degree is within the specification value. That is, the polishing time of the other polishing means is set based on the flatness measured by the flatness re-measurement means by the control means.

Preferably, in one aspect of the polishing method of the present invention, the plurality of polishing apparatuses are disposed in the polishing step, and the plate shape is determined by the plate-shaped body supply mechanism in the flatness measuring step. The body is supplied separately to one of the plurality of abrasive tools.

Preferably, the polishing apparatus of the present invention is characterized in that the polishing apparatus is provided with a plurality of the above-mentioned polishing mechanisms, and includes a plate-shaped body supply mechanism that flattens the flatness. The plate-shaped body measured by the measuring means is supplied separately to one of the plurality of polishing tools.

According to an aspect of the present invention, the operation rate of the polishing step can be increased, so that the production efficiency of the plate-shaped body can be further improved. Further, in the plurality of polishing tools, different polishing times may be set for each of the polishing tools, and the plate-shaped body may be separately supplied to and from the polishing time based on the flatness measured in the flatness measuring step. The grinding time corresponds to the grinding tool.

According to the polishing method of the plate-shaped body of the present invention and the polishing apparatus for the plate-shaped body, the production efficiency of the plate-shaped body can be improved.

10‧‧‧ grinding device

12‧‧‧Cut, chamfering device

14‧‧‧Flatness measuring device

16‧‧‧ Grinding Department

18‧‧‧ glass plate supply device

20‧‧‧Flatness re-measurement device

22‧‧‧ Controller

24‧‧‧1st grinding department

26‧‧‧2nd grinding department

28‧‧‧ polishing head

30‧‧‧ Carrier

32‧‧‧ shaft

34‧‧‧ polishing pad

36‧‧‧ polishing pad

38‧‧‧grinding platen

40‧‧‧grinding platen

50‧‧‧ grinding device

52, 54, 56, 58, 60, 62‧‧‧ grinding department

64‧‧‧Separate supply device

66‧‧‧Transportation Department

C1‧‧‧Axis of the shaft 32

C2‧‧‧Vertical shaft core

G‧‧‧glass plate

S1~S7‧‧‧ steps

Fig. 1 is a perspective view showing a configuration of a main part of a polishing apparatus for a plate-shaped body according to a first embodiment.

Fig. 2 is a block diagram showing the configuration of the polishing apparatus shown in Fig. 1.

Fig. 3 is a flow chart showing the manufacturing steps of the glass plate for FPD.

Figure 4 is a bar graph of the flatness of the surface to be polished before grinding of a plurality of glass sheets of one batch.

Figure 5 is a bar graph of the flatness of the surface to be polished after grinding using the previous grinding method.

Fig. 6 is a plan view showing the flatness of the surface to be polished after polishing by the polishing method of the embodiment Histogram.

Fig. 7 is a block diagram showing the configuration of a polishing apparatus according to a second embodiment.

Hereinafter, preferred embodiments of the polishing method of the plate-like body of the present invention and the polishing apparatus for a plate-shaped body will be described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view showing a configuration of a main part of a polishing apparatus 10 for a plate-shaped body according to a first embodiment. Fig. 2 is a block diagram showing the configuration of the polishing apparatus 10 shown in Fig. 1. The polishing apparatus 10 of the embodiment is configured based on the batch type polishing apparatus disclosed in Patent Document 1. Therefore, in FIG. 1 and FIG. 2, only the configuration of the main portion is shown, and the other device configuration is the same as that of the polishing device of Patent Document 1, and therefore the description thereof will be omitted.

The polishing apparatus 10 is a polishing apparatus in which, for example, a glass plate (plate-like body) G having a side of 600 mm or more is polished to a thickness required for a glass plate for FPD, for example, 0.2 mm to 1.5 mm, and the glass plate G is ground. The surface is ground to the flatness required for the glass plate for FPD.

As shown in Fig. 2, the polishing apparatus 10 includes a cutting and chamfering device 12 that conveys a glass plate (not shown) from a slow cooling furnace (not shown) of a floating molding device (not shown). The glass plate G (see FIG. 1) cut into a specific rectangular shape is ground to the periphery thereof; the flatness measuring device (flatness measuring means: flatness measuring step) 14 is applied to the glass plate G The flatness of the polished surface is measured; the glass plate supply device 18 supplies the glass plate G having the measured flatness to the polishing portion (polishing mechanism: polishing step) 16; the polishing portion 16 for the supplied glass plate G Polishing the surface to be polished; a flatness re-measurement device (flatness re-measurement means, flatness re-measurement step) 20, which cleans the glass plate G polished by the polished surface and measures the flatness of the surface to be polished; Controller (control mechanism) 22.

The controller 22 includes a function of changing the polishing time (polishing conditions) of the polishing unit 16 based on the flatness of the surface to be polished of the glass sheet G measured by the flatness measuring device 14, and based on the flatness re-measurement device 20 The flatness of the surface to be polished of the glass sheet G measured therein further changes the polishing time (polishing conditions) of the polishing unit 16. Again, use control The control for changing the polishing time of the polishing unit 16 by the maker 22 needs to be performed based on the flatness of the surface to be polished before polishing by the flatness measuring device 14, but it is not necessary to perform the polishing by the flatness re-measurement device 20. The flatness of the surface to be polished is then carried out. However, it is preferable that the controller 22 controls the polishing time based on the flatness of the surface to be polished after polishing, and the amount of polishing of the polishing portion 16 can be finely adjusted toward the specification value. In addition, the flatness measuring device 14 and the flatness re-measurement device 20 are the same devices, and are known devices disclosed in Patent Document 2, and thus the description thereof is omitted here.

As shown in FIG. 1 , the polishing unit 16 includes a first polishing unit 24 for rough polishing and a second polishing unit 26 for fine polishing. Further, the glass plate G before polishing is adsorbed on the opposite side of the polished surface by an adsorption sheet (not shown) which is stretched over a film frame (not shown).

Next, the polishing head 28 of the polishing unit 16 will be described. However, the polishing head 28 of the first polishing unit 24 and the polishing head 28 of the second polishing unit 26 have the same structure, and therefore, the same reference numerals will be given.

The polishing head 28 includes a frame-shaped carrier 30 and a rotating shaft 32 that is vertically coupled to the upper surface of the carrier 30. The rotating shaft 32 is coupled to an output shaft of a motor (not shown) via a speed reduction mechanism, and the carrier 30 is rotated about the axis C1 of the rotating shaft 32 by transmitting the driving force of the motor. Further, a revolving mechanism (not shown) is coupled to the rotating shaft 32, and the vertical axis C2 is revolved around the driving force of the revolving mechanism. Further, a lifting mechanism (not shown) is coupled to the rotating shaft 32, and is raised and lowered by the driving force of the lifting mechanism. Thereby, the carrier 30 moves forward and backward with respect to the polishing pad (abrasive tool) 34 of the first polishing portion 24 and the polishing pad (abrasive tool) 36 of the second polishing portion 26. The above-mentioned film frame is mounted on the lower surface of the carrier 30. Therefore, when the carrier 30 moves in and out, the surface to be polished of the glass sheet G adsorbed and held on the lower surface of the above-mentioned film frame is brought into contact with the polishing pads 34 and 36.

The polishing pad 34 is attached to the upper surface of the polishing platen 38, and a rotating shaft of a motor (not shown) is coupled to the lower portion of the polishing platen 38. Further, the polishing pad 36 is attached to the upper surface of the polishing platen 40, and a rotating shaft of a motor (not shown) is coupled to the lower portion of the polishing platen 40. because Thus, by driving the motor, the polishing platens 38 and 40 are rotated (rotating and/or revolving) around the axis of the rotating shaft.

Further, a surface of the carrier 30 includes a concave portion (not shown) that forms an air chamber (not shown) with the adsorption sheet of the film body, and a fluid supply device that supplies compressed air to the concave portion (not shown) The display 30 is coupled to the carrier 30 via a rotary joint (not shown). When the compressed air is supplied to the air chamber, the pressure of the compressed air is transmitted to the glass sheet G via the adsorption sheet, and the surface of the glass sheet G is pressed against the polishing pads 34 and 36 by the pressure to be polished. By the polishing operation of the polishing unit 16, the surface to be polished of the glass sheet G is polished to remove minute irregularities or undulations existing on the surface of the surface to be polished.

Fig. 3 is a flow chart showing an example of a manufacturing procedure of the glass plate G for FPD.

According to Fig. 3, the following steps are included: a forming step (S1) of supplying molten glass to the surface of the molten metal in the float bath to form a strip-shaped glass sheet; and a cutting and chamfering step (S2) by cutting The chamfering device 12 cuts the strip glass plate into a glass plate G of a specific size and grinds the peripheral edge portion of the glass plate G. The flatness measuring step (S3) measures the glass by the flatness measuring device 14. The flatness of the surface to be polished of the plate G; the calculation step (S4), the polishing time based on the measurement result of the flatness is calculated; the changing step (S5), the polishing time of the polishing unit 16 is changed to the calculated polishing time; and the polishing step (S6), the polished surface of the glass sheet G is polished by the polishing unit 16 by the polishing time, and the flatness remeasurement step (S7) is performed to clean the polished glass sheet G by flatness. The re-measurement device 20 measures the flatness of the surface to be polished. A glass plate G suitable for the glass plate G for FPD is produced from the molten glass by the steps of S1 to S7.

Next, a polishing method using the glass sheet G of the polishing apparatus 10 configured as described above will be described with reference to Figs. 1 to 3 .

First, before the polishing of the glass sheet G, the flatness of the polished surface of the glass sheet G is measured for each glass sheet G by the flatness measuring device 14 (S3).

Next, the controller 22 calculates the corresponding flatness for each of the glass sheets G. The optimum polishing amount is calculated, and the optimum polishing time corresponding to the optimum polishing amount is calculated (S4), and the polishing time of the polishing portion 16 is changed to the above-described optimum polishing time (S5).

Then, the polishing unit 16 polishes the surface to be polished of the glass sheet G by the optimum polishing time corresponding to the flatness (S6).

At this time, the controller 22 controls the polishing time of at least one of the first polishing unit 24 and the second polishing unit 26. For example, when the measured flatness largely deviates from the flatness of the specification, the polishing time of the first polishing unit 24 is changed long. Further, when the measured flatness is extremely deviated from the flatness of the specification, the polishing time of the first polishing unit 24 is changed to an extremely short time, and the polishing time of the second polishing unit 26 is also changed to a short time. time. In other words, it is preferable to change the polishing time in which the first polishing unit 24 and the second polishing unit 26 are integrated to be the shortest polishing time based on the measured flatness.

As a result, according to the polishing apparatus 10 of the embodiment, the production efficiency of the glass sheet G for FPD is improved as compared with the conventional polishing apparatus which is set to have a long polishing time in consideration of safety.

The above-mentioned optimum polishing amount is of course the amount of polishing for setting the flatness within the specification value, and refers to the amount of polishing set in such a manner that the peak of the distribution of the flatness of the surface to be polished after grinding (average value) The peak of the distribution of the flatness of the previous grinding method is closer to the specification value.

4 is a bar graph showing the flatness of the surface to be polished before polishing of the plurality of sheets of the glass sheets G measured by the flatness measuring device 14. 5 is a bar graph showing the flatness of the surface to be polished after the polishing method of the prior art, and FIG. 6 is a bar graph showing the flatness of the surface to be polished after the polishing method of the embodiment. In each of the figures, the horizontal axis represents flatness (μm), and the vertical axis represents frequency (%). Further, in FIGS. 5 and 6, the flatness of the surface to be polished after polishing is 1.0, and the specification value is centered, and the left side indicates the frequency within the specification value, and the specification value is centered, and the right side indicates the specification value. Frequency outside. In other words, it means that the polishing time becomes longer as it goes toward the left side, and the polishing time becomes shorter as it goes toward the right side. In the polishing method of the embodiment of Fig. 6, the optimum polishing amount is set as follows: the peak value of the distribution of the flatness of the surface to be polished after polishing (0.92), which is flatter than the previous polishing method of Fig. 5. The peak of the distribution (0.56) is closer to the specification value. Thereby, the present invention is shorter in the grinding time than before, and thus the production efficiency of the glass sheet G is improved.

Here, the polishing method of the polishing apparatus 10 of the embodiment is compared with the polishing method of the prior polishing apparatus.

As shown in FIG. 4, it is understood that the flatness of the surface to be polished before polishing of the glass sheet G is irregularly uneven in a wide range of 1.99 to 2.63. In such a glass sheet G, the previous grinding method can improve the flatness to 0.46 to 1.10 as shown in FIG. However, the conventional polishing method is a method in which the polishing time is fixed and polished regardless of the degree of flatness. Therefore, the flatness of the surface to be polished after polishing is the same as the histogram before polishing shown in FIG. The land is distributed over a wide range.

On the other hand, in the polishing method according to the embodiment, the polishing amount and the polishing time which are close to the specification value are calculated based on the flatness of the surface to be polished of each of the glass sheets G, and the glass sheet G is polished by the polishing time. In Fig. 6, the peak value (0.92) of the distribution of the flatness of the surface to be polished after grinding is in the vicinity of the specification value (1.0), that is, distributed in a narrow range. Thereby, according to the polishing method of the embodiment, it is possible to manufacture the glass sheet G of uniform quality having a small variation in flatness, and it is possible to shorten the polishing time in comparison with the previous polishing method in one batch unit.

The reason for shortening the polishing time will be described. First, as shown in Fig. 4, there is a variation in the flatness of the surface to be polished of the glass plate before polishing. In the previous grinding method, all the glass sheets were placed within the specification values, so that the glass sheets were ground with the same and a large amount of grinding. Therefore, "the total polishing time = the number of polishing sheets × the long polishing time", as a result, the polishing time becomes long, and the flatness of the polished surface of the glass plate after polishing also varies (see Fig. 5).

Therefore, in order to improve productivity, it is only necessary to set the flatness within the specification value and to maximize the flatness to the specification value. That is, the glass plate having a better flatness is maximally within the specification value with a small amount of polishing, and the glass plate having a poor flatness is maximally within the specification value with a large amount of polishing. When the flatness of the surface to be polished of all the glass sheets is within the specification value as much as possible, the variation in flatness is small (see FIG. 6).

Further, it is considered that the performance of the FPD can be stabilized if the variation in flatness is small. The reason for this is that the performance of the manufactured FPD is also stable if the glass sheet having a small degree of variation in flatness, that is, a fixed surface property is produced as a FPD under fixed manufacturing conditions.

Therefore, in the polishing method according to the embodiment, the glass sheet G is ground in an amount of polishing which is within the specification value in accordance with the flatness of the surface to be polished of each of the glass sheets G, that is, it is ground at an optimum polishing amount (= polishing time). The glass plate can shorten the grinding time compared with the previous grinding method, thereby improving productivity.

Further, according to the polishing method of the embodiment, the controller 22 of FIG. 2 further changes (feedback control) the polishing time of the polishing unit 16 based on the flatness of the polished surface after polishing measured by the flatness re-measurement device 20. In other words, based on the flatness of the surface to be polished after polishing, the polishing time (the same as the amount of polishing) that is changed by the flatness of the surface to be polished before polishing by the flatness measuring device 14 is finely adjusted, so that flatness can be produced. The deviation of the degree is further smaller than the uniform quality of the glass plate G.

That is, in the case where the flatness after polishing of the glass sheet G having a certain degree of pre-polishing is slightly deviated from the specification value, when polishing other glass sheets having the same flatness before polishing, the flatness is The other glass sheets were polished by fine-tuning the grinding time in the form of the specification value.

Further, in the polishing method of the embodiment, the glass sheet G whose flatness deviates from the specification value is also generated, but it is preferable to set the optimum polishing amount in such a manner that the frequency of the glass sheet G deviated from the specification value is It is 0.5% or less of the whole batch (parent group), preferably 0.3% or less. Moreover, the setting of the grinding time in the following manner can be effectively reduced It is preferable in terms of the short polishing time: the peak of the distribution of the flatness exists in the range of -0.15 to -0.05 with respect to the specification value.

The glass plate G whose flatness deviates from the specification value is detected by the flatness re-measurement device 20, but preferably, the second polishing portion 26 which is finely adjusted by the polishing time is used for re-polishing. Thereby, the glass plate G whose flatness deviates from the specification value can be in the specification value.

Further, in order to increase the production efficiency of the glass sheet G, another polishing portion may be provided after the flatness re-measurement device 20, and the flatness is placed in the specification by re-polishing the glass sheet G from which the specification value deviates by the other polishing portion. Within the value. That is, it is preferable that the controller 22 sets the polishing time of the other polishing unit based on the flatness measured by the flatness re-measurement device 20.

7 is a block diagram showing the configuration of the polishing apparatus 50 according to the second embodiment, and the same or similar components as those of the polishing apparatus 10 of the first embodiment shown in FIG. 1 and FIG. 2 are denoted by the same reference numerals, and their description is omitted.

The polishing apparatus 50 includes a plurality of polishing units (6 in FIG. 7), a polishing unit 52, a polishing unit 54, a polishing unit 56, a polishing unit 58, a polishing unit 60, and a polishing unit 62. Further, a separate supply device (plate-shaped body supply mechanism) 64 is provided between the polishing unit 16 and the measurement platform of the flatness measuring device 14. Further, between the polishing unit 16 and the measurement platform of the flatness re-measurement device 20, a transport unit 66 that transports the glass plate G polished by each of the polishing units 52 to 62 to the flatness re-measurement device is included. 20 measurement platform.

The polishing apparatus 50 separates and supplies the glass plate G whose flatness is measured in the flatness measuring device 14 to one of the six polishing portions 52 to 62, or is about to reach the grinding by the separation supply device 64. One polishing unit at the end time. The polishing time of the polishing portions 52 to 62 is controlled by the controller 22 based on the flatness measured by the flatness measuring device 14.

According to the polishing apparatus 50, the operation rate of the polishing unit 16 can be increased, and the production efficiency of the glass sheet G can be further improved.

Further, when the controller 22 simply controls the polishing time of the polishing portions 52 to 62, there are cases where the glass sheets G that have been polished at the polishing portions 52 to 62 have a plurality of sheets at the same time. In this case, the conveyance unit 66 conveys the glass plates G that have been polished one by one to the measurement platform of the flatness re-measurement device 20, and therefore it is necessary to wait for the polishing of the glass sheets G to be polished in the polishing portions 52 to 62. The problem of the operation rate of the part 16 is lowered.

Therefore, the polishing apparatus 50 including the plurality of polishing portions 52 to 62 needs to be polished so that the glass sheet G after polishing is not present at the same time.

An example of the polishing method will be described.

The polishing conditions for setting the flatness of the surface to be polished of the glass sheet G to the specification value are the polishing pressure of the polishing pad relative to the surface to be polished of the glass sheet G, and the relative relationship between the polishing pad and the glass sheet G, except for the polishing time. The number of rotations. Therefore, the controller 22 is based on the flatness of the surface to be polished of each of the glass sheets G measured by the flatness measuring device 14, and the polishing end time of the polishing portions 52 to 62 is not the same time, and is used for each polishing. The portions 52 to 62 control the polishing pressure and the number of rotations. In addition, the controller 22 controls the transport unit 66 such that the transport unit 66 waits in advance for one of the polishing units 52 to 62 that has finished polishing.

According to this polishing method, the problem that the glass plate G after polishing is allowed to stand by the polishing portions 52 to 62 can be eliminated, and the operation rate of the polishing portion 16 can be improved.

Further, as another polishing method, different polishing times may be set for each of the polishing portions 52 to 62, and the glass sheet G may be separately supplied to the polishing time based on the flatness measured by the flatness measuring device 14 to Polishing portions 52 to 62 corresponding to the polishing time.

Further, in the polishing apparatus 10 of FIGS. 1 and 2, the polishing unit 16 including the first polishing unit 24 and the second polishing unit 26 is exemplified, but the polishing unit may be composed of one or three or more polishing units. 16 grinding device.

Moreover, in the embodiment, the glass for FPD is exemplified as the plate-shaped body to be polished. The plate is not limited thereto, and may be a glass plate that requires surface polishing, and is not limited to a glass plate, and may be a metal or resin plate-like body that requires surface polishing.

Claims (6)

A method for polishing a plate-shaped body, comprising: a flatness measuring step of measuring a flatness of a surface to be polished of a plate-shaped body; and a polishing step of grinding a surface of the plate-shaped body having a flatness measured Polishing, and relatively pressing the surface to be polished of the plate-shaped body and the polishing tool, and rotating the surface to be polished of the plate-shaped body and the polishing tool to polish the plate-shaped body by the polishing tool The surface to be polished; and the polishing condition of the polishing step is changed based on the flatness of the surface to be polished of the plate-like body measured in the flatness measuring step. The method of polishing a plate-shaped body according to claim 1, wherein a flatness re-measurement step is performed in a subsequent step of the grinding step, and the flatness of the polished surface of the plate-like body polished in the grinding step is The re-measurement is performed, and the polishing conditions of the polishing step are further changed based on the flatness of the surface to be polished of the plate-like body measured in the flatness re-measurement step. The method of polishing a plate-shaped body according to claim 1 or 2, wherein a plurality of the polishing tools are disposed in the polishing step, and the flatness is measured in the flatness measuring step by a plate-shaped body supply mechanism The plate-shaped body is separately supplied to one of the plurality of polishing tools. A plate-shaped body polishing apparatus comprising: a flatness measuring mechanism that measures a flatness of a surface to be polished of a plate-shaped body; and a polishing mechanism that polishes a surface to be polished of the plate-shaped body on which flatness is measured, and The surface to be polished of the plate-shaped body and the polishing tool are pressed, and the surface to be polished of the plate-shaped body is rotated relative to the polishing tool to be rotated by the polishing tool. The surface to be polished of the plate-like body is polished; and a control mechanism that changes the polishing condition of the polishing mechanism based on the flatness of the surface to be polished of the plate-shaped body measured by the flatness measuring means. A polishing apparatus for a plate-shaped body according to claim 4, comprising: a flatness re-measurement means for re-measuring a flatness of a surface to be polished of said plate-like body polished by said polishing means The control means further changes the polishing conditions of the polishing means based on the flatness of the surface to be polished of the plate-shaped body measured by the flatness re-measurement means. A polishing apparatus for a plate-shaped body according to claim 4 or 5, wherein said polishing means of said polishing means is provided with a plurality of stages, and said polishing means comprises a plate-shaped body supply means for which flatness has been borrowed The plate-shaped body measured by the flatness measuring means is supplied separately to one of the plurality of polishing tools.