JP7003178B2 - Manufacturing method of disk-shaped glass substrate, manufacturing method of thin glass substrate, manufacturing method of light guide plate and disk-shaped glass substrate - Google Patents

Description

The present invention relates to a method for manufacturing a disk-shaped glass substrate, a method for manufacturing a thin glass substrate, a method for manufacturing a light guide plate, and a disk-shaped glass substrate.

Some head-mounted displays can provide augmented reality by overlaying images on landscapes. In this type of head-mounted display, a light guide body made of translucent glass may be adopted for the display unit.

For example, Patent Document 1 discloses a light guide body including a glass plate. As described in Patent Document 1, since the head-mounted display is mounted on the head, weight reduction is required. Therefore, it is desirable that the glass plate applied to the light guide has a thin plate thickness. Further, in order to display a high-resolution image, for example, a glass plate having high surface quality in terms of parallelism, surface roughness, etc. of the two main surfaces of the glass plate is desirable.

International Publication No. 2017/018375

However, in general, it is difficult to stably mass-produce a thin glass plate (hereinafter referred to as "thin plate glass substrate") with high surface quality.

For example, when a thin glass substrate having a large size and high surface quality is manufactured, the size of the glass substrate (hereinafter referred to as “glass base plate”) used as the material is also large. In such a large glass base plate, the frictional force applied to the main surface to be processed in processing such as grinding and polishing tends to be non-uniform. Therefore, the surface quality and the plate thickness become non-uniform, and it is particularly difficult for a large glass base plate to process the glass base plate thinly with high surface quality and high accuracy.

In addition, for large glass base plates, before and after the processing process, such as when installing glass base plates in each device for grinding, polishing, etc., or when transporting glass base plates between these devices. There is a high possibility that the glass base plate will be damaged while handling the glass base plate. Therefore, the yield when manufacturing a large-sized thin glass substrate with high surface quality is remarkably low.

Further, for example, in the case of manufacturing a thin glass substrate having corners such as a rectangular thin glass substrate, it is usually manufactured by processing a glass base plate having corners. In this case, especially in the vicinity of the corner portion, the frictional force applied to the surface to be processed in processing such as grinding and polishing tends to be non-uniform. Therefore, it is extremely difficult for a glass base plate having corners to be thinly processed with high surface quality and high accuracy.

Even if a thin glass substrate having corners is cut out from a thin glass substrate having a larger size, the surface quality and the plate thickness tend to be uneven in the production of a large thin glass substrate, as described above. Therefore, there is a high possibility that the surface quality and the plate thickness of the thin glass substrate having the cut corners will vary depending on which part of the large thin glass substrate is cut out. Further, as described above, the yield in manufacturing a large thin glass substrate is extremely low. In this way, even if the thin glass substrate to be manufactured is cut out from a thin glass substrate having a larger size, it is extremely difficult to stably mass-produce it with high surface quality and high precision plate thickness. ..

The present invention has been made in view of the above circumstances, such as a method for manufacturing a disk-shaped glass substrate that enables stable mass production of a thin glass substrate having high surface quality and high precision plate thickness. The purpose is to provide.

In order to achieve the above object, the method for manufacturing a disk-shaped glass substrate according to the first aspect of the present invention is:
A method for manufacturing a disk-shaped glass substrate for cutting out one or more thin glass substrates.
To prepare a disk-shaped glass base plate, which is a glass base plate having two circular main surfaces,
By chamfering the outer edges of each of the two main surfaces of the disk-shaped glass base plate,
Grinding the two main surfaces of the chamfered disk-shaped glass base plate with a double-sided grinding device, and
It includes polishing the two main surfaces of the ground disc-shaped glass base plate with a double-sided polishing device.

In order to achieve the above object, the method for manufacturing a thin glass substrate according to the second aspect of the present invention is:
To prepare a disk-shaped glass base plate, which is a glass plate having two circular main surfaces,
By chamfering the outer edges of each of the two main surfaces of the disk-shaped glass base plate,
Grinding the two main surfaces of the chamfered disk-shaped glass base plate with a double-sided grinding device, and
Polishing the two ground main surfaces with a double-sided polishing device,
This includes cutting out a plurality of thin glass substrates from the disk-shaped glass substrate obtained by the polishing.

In order to achieve the above object, the method for manufacturing a light guide plate according to the third aspect of the present invention is:
To prepare a disk-shaped glass base plate, which is a glass plate having two circular main surfaces,
By chamfering the outer edges of each of the two main surfaces of the disk-shaped glass base plate,
Grinding the two main surfaces of the chamfered disk-shaped glass base plate with a double-sided grinding device, and
Polishing the two ground main surfaces with a double-sided polishing device,
This includes cutting out a plurality of thin glass substrates from the disk-shaped glass substrate obtained by the polishing.

In order to achieve the above object, the disk-shaped glass substrate according to the fourth aspect of the present invention is
A disk-shaped glass substrate for cutting out one or more thin glass substrates.
Two circular main surfaces and
With the outer peripheral end face,
It is provided with a chamfered surface that is inclined and connected between each of the two main surfaces and the outer peripheral end surface.
The distance between the two main surfaces is 100-350 μm.
The parallelism of the two main surfaces is less than 1.0 μm.

According to the present invention, it is possible to stably produce a large number of thin glass substrates having high surface quality and high precision plate thickness.

It is a perspective view of the disk-shaped glass substrate which concerns on one Embodiment of this invention. FIG. 1 is an enlarged view showing a cross section CS1 in the vicinity of the left end of the disk-shaped glass substrate shown in FIG. 1 when viewed from the front. It is a flowchart of the process included in the manufacturing method of the disk-shaped glass substrate which concerns on one Embodiment of this invention. It is a perspective view of the disk-shaped glass base plate first prepared by the manufacturing method of the disk-shaped glass substrate which concerns on one Embodiment. FIG. 4 is an enlarged view showing a cross section CS2 in the vicinity of the left end of the disk-shaped glass base plate shown in FIG. 4 when viewed from the front. It is a figure which magnifies and shows the cross section in the vicinity of the left end of a chamfered disk-shaped glass base plate when viewed from the front. It is a figure which shows the structure of the double-sided grinding apparatus which concerns on one Embodiment. It is a flowchart of the process included in the manufacturing method of the thin glass substrate which concerns on one Embodiment of this invention. It is a figure which shows an example of the part where the disk-shaped glass substrate is cut by the cutting process included in the manufacturing method of the thin glass substrate which concerns on one Embodiment. It is a flowchart of the process included in the manufacturing method of the light guide plate which concerns on one Embodiment of this invention. It is a figure which shows an example of the light guide plate manufactured by the manufacturing method of the light guide plate which concerns on one Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same elements are given the same reference numerals throughout the figure. Although the terms top, bottom, front, back, left, and right are used in the description and drawings of the embodiments of the present invention, these are used to explain the direction and do not limit the present invention. .. In the figure, the ratio of the dimensions of each part is changed as appropriate for the sake of clarity.

(Structure of disk-shaped glass substrate 100)
The disk-shaped glass substrate 100 according to the embodiment of the present invention is a thin glass plate having a disk shape, as shown in FIG. 1 which is a perspective view and FIG. 2 which is an enlarged cross-sectional view. The refractive index of the disk-shaped glass substrate 100 is preferably 1.60 or more.

In the following, "thin plate glass substrate" means a glass plate having a thin plate thickness.

The disk-shaped glass substrate 100 is an intermediate for cutting out one or a plurality of thin glass substrates having a size smaller than this. The cut-out thin glass substrate is used as a light guide plate, for example, by a single substance or by appropriately combining a plurality of them. When a plurality of cut out thin glass substrates are combined and used as a light guide plate, typically, the cut out thin glass substrates are laminated and used as a light guide plate. The light guide is applied to a display device such as a head-mounted display, for example.

The disk-shaped glass substrate 100 has two main surfaces 101a and 101b, an outer peripheral end surface 102a, and a chamfered surface 103a and 103b. FIG. 2 is an enlarged view of the cross section CS1 surrounded by the alternate long and short dash line of FIG. 1 as viewed from the front shown in FIG. The cross section CS1 is a surface extending in the vertical direction and the horizontal direction, and is a cross section along the respective diameter directions of the main surfaces 101a and 101b. Since the cross section CS1 shown in FIG. 2 is extremely thin, the cross section CS1 surrounded by the alternate long and short dash line appears as a generally thick straight line.

The two main surfaces 101a and 101b are generally circular planes arranged in the vertical direction. The diameter of each of the two main surfaces 101a and 101b is, for example, 70 [mm (millimeters)] to 210 [mm].

The vertical length between the two main surfaces 101a and 101b, that is, the plate thickness of the disk-shaped glass substrate 100 excluding the outer peripheral end faces 102a and the chamfered surfaces 103a and 103b is, for example, 50 [μm (micrometer)] to 500. [Μm]. The plate thickness of the disk-shaped glass substrate 100 excluding the outer peripheral end faces 102a and the chamfered surfaces 103a and 103b is preferably 100 [μm] to 400 [μm], and more preferably 100 [μm] to 350 [μm]. be.

The parallelism of the two main surfaces 101a and 101b is, for example, less than 1.0 [μm], preferably 0.95 [μm] or less, and more preferably 0.5 [μm] or less. The parallelism of the two main surfaces 101a and 101b may be 0.05 [μm] or more.

Here, the parallelism is a value called TTV (Total Tickness Variation), and is a disk measured in the plate thickness direction (vertical direction in the present embodiment) with one of the main surfaces 101a and 101b as a reference plane. It is the difference between the maximum value and the minimum value of the length on the entire surface of the shaped glass substrate 100.

The roughness (root mean square roughness) Rq of the two main surfaces 101a and 101b is, for example, 0.4 [nm] or less.

The outer peripheral end surface 102a is a surface forming a radial end of the disk-shaped glass substrate 100, and is a curved surface that extends slightly in the vertical direction. Specifically, the outer peripheral end surface 102a has a substantially circular shape when viewed from above or below, and has an extremely elongated rectangle which is short in the vertical direction when viewed from the side. Here, the side is a direction perpendicular to the vertical direction.

The chamfered surfaces 103a and 103b are surfaces that are inclined and connected between each of the two main surfaces 101a and 101b and the outer peripheral end surface 102a, and form an annular shape when viewed from above or below. That is, the upper chamfered surface 103a is an annular surface that is inclined and connected between the outer edge portion 104a of the upper main surface 101a and the upper end portion 105a of the outer peripheral end surface 102a. The lower chamfered surface 103b is an annular surface that is inclined and connected between the outer edge portion 104b of the lower main surface 101b and the lower end portion 106a of the outer peripheral end surface 102a.

In the present embodiment, the chamfered surfaces 103a and 103b form a straight line when viewed from the side (see FIG. 2). Further, since the chamfered surfaces 103a and 103b are "inclined" as described above, they intersect both the two main surfaces 101a and 101b and the outer peripheral end surface 102a. The chamfered surfaces 103a and 103b according to the present embodiment intersect with each of the two main surfaces 101a and 101b at an obtuse angle with respect to any of the outer peripheral end surfaces 102a (see FIG. 2). The chamfered surfaces 103a and 103b may be curved when viewed from the side.

So far, the configuration of the disk-shaped glass substrate 100 according to the present embodiment has been described.

The disk-shaped glass substrate 100 according to the present embodiment is an intermediate for cutting out one or a plurality of thin glass substrates. Further, the disk-shaped glass substrate 100 has a plate thickness of 100 [μm] to 350 [μm] except for the outer peripheral end faces 102a and the chamfered surfaces 103a and 103b, and the parallelism of the two main surfaces 101a and 101b is 1. It has high surface quality and high precision plate thickness of less than 0 [μm]. Therefore, it is possible to cut out a thin glass substrate having high surface quality and high precision plate thickness.

Further, the disk-shaped glass substrate 100 includes chamfered surfaces 103a and 103b. Therefore, the possibility that the disk-shaped glass substrate 100 is damaged when the thin glass substrate is cut out is reduced, and the thin glass substrate can be cut out with a higher yield than when the chamfered surfaces 103a and 103b are not provided.

Further, since the disk-shaped glass substrate 100 not only has the chamfered surfaces 103a and 103b but also has a disk-like shape, as will be described in detail later, a relatively large thin glass substrate having high surface quality and high precision plate thickness. Even so, it can be stably manufactured with a high yield.

Therefore, it is possible to stably produce a large number of thin glass substrates having a desired shape having high surface quality and high precision plate thickness.

Further, the refractive index of the disk-shaped glass substrate 100 may be 1.60 or more, and the parallelism of the two main surfaces 101a and 101b may be 0.5 [μm] or less. According to this, for the same reason as described above, it becomes possible to stably produce a large number of thin glass substrates having a desired shape having higher surface quality and higher precision plate thickness.

Further, the thin glass substrate cut out from the disk-shaped glass substrate 100 may be a light guide plate used alone or in combination of a plurality of thin plates by a method such as laminating. According to this, for the same reason as described above, it becomes possible to stably produce a large amount of light guide plates having a desired shape having high surface quality and high precision plate thickness.

(Manufacturing method of disk-shaped glass substrate 100)
From here, a method for manufacturing the disk-shaped glass substrate 100, which is an intermediate, will be described.

The method for manufacturing the disk-shaped glass substrate 100 is a method for manufacturing the disk-shaped glass substrate 100, and includes, for example, the process shown in the flowchart of FIG.

A disk-shaped glass base plate 107a is prepared (step S1).

The disk-shaped glass base plate 107a is a disk-shaped glass substrate having a thickness thicker than that of the disk-shaped glass substrate 100 manufactured as an intermediate. The plate thickness t1 of the disk-shaped glass base plate 107a is, for example, 0.5 [mm] to 1.0 [mm]. The refractive index of the disk-shaped glass base plate 107a is preferably 1.60 or more. The accuracy of the plate thickness and the quality of each of the main surfaces 101c and 101d may be lower than the accuracy or quality of the disk-shaped glass substrate 100.

The disk-shaped glass base plate 107a has two main surfaces 101c and 101d and an outer peripheral end surface 102b as shown in FIG. 4 which is a perspective view and FIG. 5 which is an enlarged cross-sectional view.

FIG. 5 is an enlarged view of the cross section CS2 surrounded by the alternate long and short dash line of FIG. 4 as viewed from the front shown in FIG. The cross section CS2 corresponds to the cross section CS1 of FIG. 1, and is a surface extending in the vertical direction and the horizontal direction, and is along the respective diameter directions of the main surfaces 101c and 101d. Since the cross section CS2 shown in FIG. 4 is extremely thin, the cross section CS2 surrounded by the alternate long and short dash line appears as a generally thick straight line like the cross section CS1 in FIG.

Such a disk-shaped glass base plate 107a may be manufactured by an appropriate molding process.

More specifically, for example, the disk-shaped glass base plate 107a may be manufactured by cutting out a columnar glass from a block of prismatic glass formed of high-refractive glass and then slicing it into a disk shape. Further, for example, the disk-shaped glass base plate 107a may be manufactured by cutting out a large glass plate formed by a float method or a down draw method to a predetermined size. Further, for example, the disk-shaped glass base plate 107a may be manufactured by press-molding molten glass with a pair of dies.

Here, the outer edge portions 104c and 104d forming the outer edges of the main surfaces 101c and 101d of the disk-shaped glass base plate 107a do not have to be chamfered. That is, each of the main surfaces 101c and 101d of the disk-shaped glass base plate 107a and the outer peripheral end surface 102b intersect at the outer edge portions 104c and 104d. In other words, each of the outer edge portions 104c and 104d is a portion that becomes a substantially linear boundary between the main surface 101c and 101d of the disk-shaped glass base plate 107a and the outer peripheral end surface 102b, and forms a ridge line. In the present embodiment, when viewed from the side, each of the main surfaces 101c and 101d and the outer peripheral end surface 102b intersect at a right angle (see FIG. 5).

For example, when viewed from the side, the main surfaces 101c and 101d are curved, or the outer peripheral end surface 102b is curved in the vertical direction, so that each of the main surfaces 101c and 101d and the outer peripheral end surface 102b form an acute angle. It may be crossed.

See again in FIG.
Chamfering is performed on the disk-shaped glass base plate 107a (step S2). In the chamfering step (step S2), the outer edges 104c and 104d of the two main surfaces 101c and 101d of the disk-shaped glass base plate 107a are chamfered.

By performing the chamfering step (step S2), the outer edge portions 104c and 104d that are the boundaries between the main surfaces 101c and 101d of the disk-shaped glass base plate 107a and the outer peripheral end faces 102b are removed. Then, as shown in FIG. 6, which is an enlarged cross-sectional view, the chamfered surfaces 103c and 103d, which are the surfaces connecting the main surfaces 101e and 101f of the disk-shaped glass base plate 107b and the outer peripheral end faces 102c, are the disc-shaped glass base plates. It is formed on 107b.

Specifically, the upper chamfered surface 103c is an annular surface that is inclined and connected between the outer edge portion 104e of the upper main surface 101e and the upper end portion 105b of the outer peripheral end surface 102c. The lower chamfered surface 103d is an annular surface that is inclined and connected between the outer edge portion 104f of the lower main surface 101d and the lower end portion 106b of the outer peripheral end surface 102c.

In the present embodiment, as shown in FIG. 6, chamfered surfaces 103c and 103d forming a straight line when viewed from the side are formed on the disk-shaped glass base plate 107b.

Such a chamfering step (step S2) is performed by a mechanical process such as grinding using a grindstone, for example. The grinding surface of the grindstone may be set at an inclination angle of 30 to 60 degrees, preferably 45 degrees with respect to each of the two main surfaces 101c and 101d. As a result, the angle formed by the main surfaces 101e and 101f and the chamfered surfaces 103c and 103d when viewed from the side, and the angle formed by each of the outer peripheral end surfaces 102c and the chamfered surfaces 103c and 103d when viewed from the side are determined. It is formed at an obtuse angle of 120 to 150 degrees, preferably 135 degrees.

Here, FIG. 6 shows an enlarged cross section of the chamfered disc-shaped glass base plate 107b after the chamfering step (step S2), that is, the cross section near the left end of the chamfered disc-shaped glass base plate 107b when viewed from the front. It is a figure. Although the position and range of the disc-shaped glass base plate 107b in the cross section here are not shown, they are surfaces extending in the vertical and horizontal directions as in FIGS. 2 and 5, and have diameters of the main surfaces 101e and 101f, respectively. It is a cross section along the direction.

In FIG. 6, the enlarged cross section of the disk-shaped glass base plate 107b is shown by a solid line. Further, in FIG. 6, for comparison, an enlarged cross-sectional view (corresponding to the enlarged cross-sectional view shown in FIG. 5) of the disc-shaped glass base plate 107a before chamfering prepared in step S1 is shown by a alternate long and short dash line. Further, in FIG. 6, for comparison, an enlarged cross-sectional view (corresponding to the enlarged cross-sectional view shown in FIG. 2) of the disk-shaped glass substrate 100 manufactured as an intermediate is shown by a dotted line.

As described above, the enlarged views of the disc-shaped glass base plates 107a and 107b and the disc-shaped glass substrate 100 shown in FIG. 6 are substantially the same for each of the disc-shaped glass base plates 107a and 107b and the disc-shaped glass substrate 100 as described above. A cross section of the position and range as viewed from the front is shown. That is, in FIG. 6, the surfaces of the disc-shaped glass base plates 107a and 107b and the disc-shaped glass substrate 100 crossing the center in the vertical direction overlap each other, and the main surfaces 101a to 101f viewed from the vertical direction are each overlapped with each other. It is a figure which shows the enlarged cross-section when each of the disk-shaped glass base plates 107a, 107b and the corresponding portion of the disk-shaped glass substrate 100 are viewed from the front, arranged so that the centers coincide with each other.

As can be seen from FIG. 6, the diameters of the main surfaces 101e and 101f of the disk-shaped glass base plate 107b and the vertical length of the outer peripheral end surface 102c are determined in step S1 as a result of the chamfering step (step S2). The diameters of the main surfaces 101c and 101d of the prepared disc-shaped glass base plate 107a and the length of the outer peripheral end surface 102b in the vertical direction are shorter than each.

Further, as shown in FIG. 6, the outer peripheral end surface 102c of the disk-shaped glass base plate 107b and the upper end portion 105b and the lower end portion 106b thereof are generally the outer peripheral end surface 102a of the disk-shaped glass substrate 100 which is an intermediate and the upper end thereof. It coincides with each of the portion 105a and the lower end portion 106a. A part of the upper and lower chamfered surfaces 103c and 103d of the disk-shaped glass base plate 107b is generally the upper and lower chamfered surfaces 103a and 103b of the disk-shaped glass substrate 100 which is an intermediate as shown in FIG. 6, respectively. Matches with.

Further, referring to FIG. 6, the outer peripheral end surface 102c of the chamfered disk-shaped glass base plate 107b and the outer peripheral end surface of the chamfered disk-shaped glass base plate 107b having a plate thickness other than the chamfered surfaces 103c and 103d are t1 [mm]. When the plate thickness of 102c is t2 [mm], the following equation (1) is satisfied.
t1 × 0.15 <t2 <t1 × 0.4 ... Equation (1)

The chamfering step (step S2) is not limited to the mechanical treatment, but may be performed by a chemical treatment such as etching. Chamfered surfaces 103c and 103d that form a curve when viewed from the side may be formed.

See again in FIG.
Grinding is performed on the two main surfaces 101e and 101f of the chamfered disk-shaped glass base plate 107b (step S3). The grinding step (step S3) is mainly performed for the purpose of adjusting the plate thickness of the disc-shaped glass base plate 107b and adjusting the flatness and parallelism of the two main surfaces 101e and 101f of the disc-shaped glass base plate 107b. Will be.

The allowance in the grinding step (step S3) is, for example, about 120 [μm] to 400 [μm]. Here, the removal allowance means the length of the portion removed in the process in the vertical direction.

In the grinding step (step S3), for example, the two main surfaces 101e and 101f of the chamfered disk-shaped glass base plate 107b are simultaneously ground by using the double-sided grinding device 108 shown in FIG. 7.

FIG. 7 shows the configuration of the double-sided grinding device 108. With reference to this figure, a method of grinding the main surfaces 101e and 101f of the disk-shaped glass base plate 107b in the grinding step (step S3) will be described.

As shown in FIG. 7, the double-sided grinding device 108 has a lower surface plate 109, an upper surface plate 110, an internal gear 111, a sun gear 112, and a substantially disk-shaped carrier 113 provided with a holding hole.

A diamond sheet (not shown) is planarly adhered to each surface of the upper surface of the lower surface plate 109 and the lower surface of the upper surface plate 110. The surface of this diamond sheet becomes the grinding surface. The particle size of the fixed abrasive grains is, for example, about 10 [μm].

The internal gear 111 is a substantially hollow annular member having a tooth profile on the inner surface. The sun gear 112 is a substantially columnar member arranged at the center of the internal gear 111, and has a tooth profile on the outer peripheral surface.

The carrier 113 is a holding member that holds the disk-shaped glass base plate 107b by the holding holes. Specifically, the disk-shaped glass base plate 107b is held by the carrier 113 as shown in FIG. 7 by accommodating the outer peripheral end surface 102c so as to be substantially in close contact with the wall surface forming the holding hole of the carrier 113. ..

Further, teeth are provided on the outer peripheral surface of the carrier 113. The carrier 113 holding the disk-shaped glass base plate 107b is arranged so that the teeth of the carrier 113 mesh with each tooth between the internal gear 111 and the sun gear 112. FIG. 7 shows an example in which four carriers 113 are arranged between the internal gear 111 and the sun gear 112.

The number of carriers 113 arranged in the double-sided grinding device 108 is not limited to four, and may be one, two, three, or five or more. Further, the number of the disk-shaped glass base plates 107b held by one carrier 113 is not limited to one, and may be a plurality.

The disk-shaped glass base plate 107b held by the carrier 113 is sandwiched between the lower surface plate 109 and the upper surface plate 110 at a predetermined pressure. Then, either or both of the upper surface plate 110 and the lower surface plate 109 move. As a result, the disc-shaped glass base plate 107b and the surface plates 109 and 110 move relatively, and the fixed abrasive grains contained in the diamond sheet described above cause the two main surfaces 101e and 101f of the disc-shaped glass base plate 107b to move. Grinded at the same time.

Free abrasive grains may be used instead of the fixed abrasive grains. In this case, the disk-shaped glass base plate 107b is ground by the same method as in the case of using the above-mentioned fixed abrasive grains by using a grinding pad instead of the above-mentioned diamond sheet and a grinding slurry containing free abrasive grains instead of the above-mentioned fixed abrasive grains. can do.

Refer to FIG. 3 again.
After the grinding step (step S3) is performed, the disc-shaped glass base plate (not shown), that is, the two main surfaces of the ground disc-shaped glass base plate are polished (step S4). The polishing step (step S4) is performed for the purpose of removing scratches and strains during grinding, mirroring, and the like.

The removal allowance in the polishing step (step S4) is, for example, about 10 [μm] to 150 [μm], preferably 20 [μm] to 150 [μm]. It is desirable that the polishing step (step S4) is performed in multiple steps as described later, and it is preferable that the above-mentioned disk-shaped glass substrate 100 is produced, for example, with reference to FIGS. 1 and 2.

In the polishing step (step S4), for example, the two main surfaces of the ground disc-shaped glass base plate are simultaneously polished using a double-sided polishing device.

The double-sided polishing apparatus has substantially the same configuration as the double-sided grinding apparatus 108 described above, except that polishing pads are attached to the upper surface of the lower surface plate 109 and the lower surface of the upper surface plate 110 in place of the diamond sheet. It may be a thing. The polishing pad is a member of an annular flat plate as a whole, and is, for example, a resin polisher. Further, in the polishing step (step S4), a polishing slurry containing polishing abrasive grains is used.

Although the double-sided polishing apparatus is not shown for the sake of simplicity, in the following description of the polishing step (step S4), the components of the double-sided polishing apparatus used in this step (step S4) are described in the double-sided grinding apparatus 108 shown in FIG. The reference code of the corresponding component is attached.

The carrier 113 holds the ground disc-shaped glass base plate in the same manner as the double-sided grinding device 108 described above. The carrier 113 holding the ground disc-shaped glass base plate is arranged so that the teeth of the carrier 113 mesh with each tooth between the internal gear 111 and the sun gear 112. The disk-shaped glass base plate held by the carrier 113 is sandwiched between the lower surface plate 109 provided with the polishing pad and the upper surface plate 110 with a predetermined pressure. Then, while supplying the polishing slurry, either or both of the upper surface plate 110 and the lower surface plate 109 move. As a result, the ground disc-shaped glass base plate and the surface plates 109 and 110 move relatively, and the two main surfaces of the disc-shaped glass base plate are simultaneously polished by the free abrasive grains contained in the polishing slurry. ..

As shown in FIG. 3, the polishing step (step S4) according to the present embodiment includes a first polishing step (step S41) and a second polishing step (step S42).

The first polishing step (step S41) is mainly for the purpose of removing scratches and strains remaining on the main surface after grinding, or adjusting minute irregularities (microwaveness, roughness, etc.) on the main surface after grinding. It is done as. In the first polishing step (step S41), polishing of the two main surfaces of the disk-shaped glass base plate after the grinding step (step S3) is performed using the double-sided polishing device as described above. The removal allowance in the first polishing step (step S41) is, for example, about 10 [μm] to 100 [μm].

In the first polishing step (step S41), for example, a polishing slurry containing cerium oxide abrasive grains, zirconia abrasive grains, or the like having a particle size of about 1 [μm] to 2 [μm] as free abrasive grains is used.

In the first polishing step (step S41), it is preferable to change at least one of the polishing pad and the polishing slurry to perform polishing in multiple stages. That is, in this case, it is preferable that the combination of the polishing pad and the polishing slurry applied to the double-sided polishing apparatus is different from each other at each stage of the first polishing step (step S41). In this way, by performing the first polishing step (step S41) in multiple steps, the parallelism of the disc-shaped glass base plate can be adjusted within the range of 0.05 [μm] to 0.95 [μm]. As a result, it becomes possible to obtain a disk-shaped glass substrate 100 having high surface quality and high precision plate thickness.

The second polishing step (step S42) is mainly performed for the purpose of mirroring the main surface and reducing the roughness. In the second polishing step (step S42), polishing of the two main surfaces of the disc-shaped glass base plate after the first polishing step (step S41) is performed using the double-sided polishing device as described above. .. The removal allowance in the second polishing step (step S42) is, for example, about 1 [μm].

In the second polishing step (step S42), the types and particle sizes of the free abrasive grains contained in the polishing slurry and the hardness of the resin polisher are different from those in the first polishing step (step S41). In the second polishing step (step S42) according to the present embodiment, the particle size of the free abrasive grains, for example, colloidal silica turbid in the slurry, is about 10 [nm (nanometer)] to 50 [nm]. Fine particles are used.

In the second polishing step (step S42), the type and particle size of the free abrasive grains contained in the polishing slurry and at least one of the polishing pads may be different from those in the first polishing step (step S41). That is, in the first polishing step (step S41) and the second polishing step (step S42), it is preferable that the combination of the hardness of the resin polisher applied to the double-sided polishing device and the polishing slurry is different from each other.

By carrying out the second polishing step (step S42), the roughness (root mean square roughness) Rq of the main surface can be set to 0.4 [nm] or less. As a result, it becomes possible to manufacture a disk-shaped glass substrate 100 having high surface quality, and by extension, it becomes possible to manufacture a thin glass substrate having high surface quality by cutting out from the disk-shaped glass substrate 100.

By performing a grinding treatment (step S3) and a polishing treatment (step S4) on each of the two main surfaces 101e and 101f of the disk-shaped glass base plate 107b, a highly accurate plate thickness as shown in FIG. 1 can be obtained. The disk-shaped glass substrate 100 can be manufactured. The plate thickness t3 of the manufactured disk-shaped glass substrate 100 is, for example, 50 [μm] to 500 [μm], preferably 100 [μm] to 400 [], except for the outer peripheral end faces 102a and the chamfered surfaces 103a and 103b. μm], more preferably 100 [μm] to 350 [μm].

Further, the disk-shaped glass substrate 100 to be produced may be a large one having a diameter of 70 to 210 [mm]. The disk-shaped glass substrate 100 to be produced has a high surface quality in which the parallelism of the two main surfaces 101a and 101b is less than 1.0 [μm], preferably 0.95 [μm] or less. , More preferably 0.5 [μm] or less. The parallelism of the two main surfaces 101a and 101b of the disk-shaped glass substrate 100 may be 0.05 [μm] or more.

In the grinding step (step S3) and the polishing step (step S4), at least a part of each of the chamfered surfaces 103c and 103d formed in the chamfering step (step S2) remains after the steps S3 to S4. The main surface of the disc-shaped glass base plate is ground and polished by the chamfering allowance. As a result, the chamfered surfaces 103a and 103b can be reliably provided on the disk-shaped glass substrate 100 produced by polishing (step S4).

Further, the outer peripheral end surface 102a and the chamfered surfaces 103a, 103b of the disk-shaped glass substrate 100 produced by polishing the outer peripheral end surface 102c of the chamfered disk-shaped glass base plate 107b by t2 [mm] and polishing (step S4). When the plate thickness other than is t3 [mm] (see FIG. 6), the following equation (2) is satisfied.
t3 × 0.5 <t2 ... Equation (2)

See again in FIG.
After the polishing treatment (step S4), the disk-shaped glass substrate 100 is washed with a neutral detergent, pure water, IPA (isopropyl alcohol), or the like. As a result, the disk-shaped glass substrate 100 shown in FIG. 1 is completed. The shape and size of the disk-shaped glass substrate 100, such as the plate thickness of the disk-shaped glass substrate 100, are usually almost the same before and after the cleaning process (step S5).

The method for manufacturing the disk-shaped glass substrate 100 according to the present embodiment includes a chamfering step (step S2). Damage to the disc-shaped glass base plate due to cracking or the like can be suppressed during the subsequent processing steps (steps S3 to S5) and before and after each of the processing steps (steps S3 to S5).

Further, since the grinding step (step S3) and the polishing step (step S4) are performed after the chamfering step (step S2) and the object of grinding and polishing is a disk shape, the corners are not included. As a result, the frictional force applied to each of the main surfaces 101e and 101f of the disc-shaped glass base plate 107b tends to be uniform in steps S3 to S4. As a result, the disk-shaped glass base plate 107b can be thinly processed with high surface quality and high accuracy.

Further, with reference to FIGS. 1 and 2, a disk-shaped glass substrate 100 having a high surface quality and a high-precision plate thickness as described above can be manufactured. That is, since the disk-shaped glass substrate 100 has a uniform plate thickness and a uniform and high surface quality, it is possible to cut out a thin glass substrate having a desired shape or size having a high surface quality and a highly accurate plate thickness.

Further, by including the chamfering step (step S2), the chamfered surfaces 103a and 103b are also formed on the produced disk-shaped glass substrate 100. As a result, the possibility that the disk-shaped glass substrate 100 is damaged when the thin glass substrate is cut out from the disk-shaped glass substrate 100 is reduced, and the thin glass substrate can be cut out with a higher yield than when the chamfered surfaces 103a and 103b are not provided. can.

Therefore, it is possible to stably produce a large number of thin glass substrates having a desired shape having high surface quality and high precision plate thickness.

Further, as described above, since the grinding step (step S3) and the polishing step (step S4) are performed after the chamfering step (step S2) and the object of grinding and polishing is a disk shape, the corners are not included. .. Therefore, it is possible to stably manufacture a disk-shaped glass substrate 100 having a large diameter of 70 to 210 mm, high surface quality, and a high-precision plate thickness with a high yield. From the large disk-shaped glass substrate 100, it is usually possible to cut out more thin glass substrates than the small disk-shaped glass substrate 100. Therefore, by cutting out the thin glass substrate from the large disk-shaped glass substrate 100, it becomes possible to facilitate stable mass production of the thin glass substrate having high surface quality and high precision plate thickness.

(Manufacturing method of thin glass substrate 114)
From here, a method of manufacturing the thin glass substrate 114 will be described.

The method for manufacturing a thin glass substrate 114 according to the present embodiment is a method for manufacturing a plurality of thin glass substrates 114 from an intermediate disk-shaped glass substrate 100, for example, the process shown in the flowchart of FIG. include.

In the method for manufacturing the thin glass substrate 114 according to the present embodiment, as shown in FIG. 8, after steps S1 to S5 described above with reference to FIG. 3, a plurality of rectangular thin plates are formed from the disk-shaped glass substrate 100. The glass substrate 114 is cut out (step S6). In other words, the cutting process (step S6) is performed on the disk-shaped glass substrate 100 manufactured by the method for manufacturing the disk-shaped glass substrate 100.

Here, in FIG. 8, for the sake of simplicity, the same steps as in steps S1 to S5 in the method for manufacturing the disk-shaped glass substrate 100 are omitted.

Specifically, in the cutting process (step S6), as shown in FIG. 9, the disk-shaped glass substrate 100 is cut along the straight line of the dotted line in the figure. As a result, a plurality of rectangular thin glass substrates 114 as shown in an enlarged manner in FIG. 9 are cut out from the disk-shaped glass substrate 100.

According to the method for manufacturing the thin glass substrate 114, as described above, the disk-shaped glass substrate 100 having a uniform plate thickness and uniform high surface quality can be produced by the steps S1 to S5. With such a disk-shaped glass substrate 100, it is possible to obtain a plurality of thin glass substrates 114 having high surface quality and high precision plate thickness regardless of the place where they are cut out. Further, even if the thin glass substrate 114 has corners such as a rectangle, the thin glass substrate 114 having high surface quality and high precision plate thickness can be obtained.

Further, by including the chamfering step (step S2), as described above, the possibility that the disk-shaped glass substrate 100 is damaged when the thin glass substrate 114 is cut out from the disk-shaped glass substrate 100 is reduced. Therefore, even a thin glass substrate 114 having corners such as a rectangle as illustrated here can be obtained with a higher yield than when the chamfered surfaces 103a and 103b are not provided.

Therefore, it is possible to stably produce a large number of thin glass substrates 114 having high surface quality and high precision plate thickness and having corners.

Although an example in which a plurality of rectangular thin glass substrates 114 are cut out in the cutting process (step S6) has been described, only one thin glass substrate 114 may be cut out from the disk-shaped glass substrate 100. Further, in the cutting process (step S6), the shape and size of each of the one or a plurality of thin glass substrates 114 cut out from the disk-shaped glass substrate 100 may be appropriately changed, for example, a shape having no corners. It may be. According to this, it becomes possible to stably produce a thin glass substrate 114 having a desired shape having a high surface quality and a high precision plate thickness in a large quantity.

The thin glass substrate 114 manufactured by the method for manufacturing the thin glass substrate 114 described here may be used alone as a light guide plate. In this case, the method for manufacturing the thin glass substrate 114 described here may be adopted as the method for manufacturing the light guide plate. This makes it possible to stably produce a large number of light guide plates having a desired shape having high surface quality and high precision plate thickness.

(Manufacturing method of light guide plate)
From here, a method of manufacturing the light guide plate 115 will be described.

The method for manufacturing the light guide plate 115 according to the present embodiment is a method for manufacturing the light guide plate 115 by combining a plurality of thin glass substrates 114, and includes, for example, the step shown in the flowchart of FIG.

In the method for manufacturing the light guide plate 115 according to the present embodiment, as shown in FIG. 10, after the cutting process (step S6) described above with reference to FIG. 8, the cut-out thin glass substrate 114 is laminated. (Step S7). In other words, the laminating step (step S7) is performed on the thin glass substrate 114 manufactured by the method for manufacturing the thin glass substrate 114.

Here, in FIG. 10, for the sake of simplicity, the same steps as in steps S1 to S6 in the method for manufacturing the thin glass substrate 114 are omitted. That is, the manufacturing method steps S1 to S5 of the light guide plate 115 may be the same as each of steps S1 to S5 in the manufacturing method of the disk-shaped glass substrate 100.

Specifically, in the laminating step (step S7), the thin glass substrates 114 are laminated by fixing the thin glass substrates 114 adjacent to each other in the vertical direction, whereby the light guide plate 115 as shown in FIG. 11 is manufactured.

Although FIG. 11 shows an example in which four thin glass substrates 114 are laminated, the number of thin glass substrates 114 laminated in the laminating step (step S7) may be appropriately determined.

According to the method for manufacturing the light guide plate 115, the light guide plate 115 can be manufactured by cutting out a plurality of thin glass substrates 114 having high surface quality and high precision plate thickness and laminating them. As described above, it is possible to stably produce a large number of thin glass substrates 114 having high surface quality and high precision plate thickness and having corners. Therefore, it is possible to stably produce a large number of light guide plates 115 having high surface quality and high precision plate thickness and having corners.

The thin glass substrate 114 cut out from the disk-shaped glass substrate 100 in the cutting process (step S6) may have a desired shape and size as described above. According to this, it becomes possible to stably produce a large amount of a light guide plate 115 having a desired shape having a high surface quality and a high precision plate thickness.

Although one embodiment and modifications of the present invention have been described above, the present invention is not limited thereto. For example, the present invention also includes a form in which the embodiments described above and modifications are appropriately combined, and a form in which the embodiments are appropriately modified.

INDUSTRIAL APPLICABILITY The present invention can be used for mass production of thin glass substrates having high surface quality, such as glass substrates applied to display devices such as head-mounted displays.

100 Disc-shaped glass substrate 101a to 101f Main surface 102a to 102c Outer peripheral end surface 103a to 103d Chamfered surface CS1, CS2 Cross section 104a to 104f Outer edge portion 105a to 105b Upper end portion 106a to 106b Lower end portion 107a to 107b Disc-shaped glass base plate 108 Double-sided grinding Equipment 109 Lower surface plate 110 Upper surface plate 111 Internal gear 112 Sun gear 113 Carrier 114 Thin glass substrate 115 Light guide plate

Claims (11)

A method for manufacturing a disk-shaped glass substrate for cutting out one or more thin glass substrates.
To prepare a disk-shaped glass base plate, which is a glass base plate having two circular main surfaces,
By chamfering the outer edges of each of the two main surfaces of the disk-shaped glass base plate,
Grinding the two main surfaces of the chamfered disk-shaped glass base plate with a double-sided grinding device, and
The disk-shaped glass is characterized by comprising polishing the two main surfaces of the ground disk-shaped glass base plate with a double-sided polishing device to produce a disk-shaped glass substrate having a plate thickness of 50 to 500 μm. Substrate manufacturing method. The plate thickness of the disk -shaped glass substrate is 350 μm or less.
The method for manufacturing a disk-shaped glass substrate according to claim 1. The method 1 or 2 is characterized in that a disk-shaped glass substrate having a diameter of 70 to 210 mm is produced by polishing the two main surfaces of the ground disk-shaped glass base plate. The method for manufacturing a disk-shaped glass substrate according to the description. The polishing is characterized in that a disk-shaped glass substrate having a root mean square roughness Rq of 0.4 nm or less is produced by polishing the two main surfaces of the ground disk-shaped glass base plate. The method for manufacturing a disk-shaped glass substrate according to any one of claims 1 to 3. From claim 1, the polishing is characterized in that a disk-shaped glass substrate having a parallelism of less than 1.0 μm is produced by polishing the two main surfaces of the ground disk-shaped glass base plate. 4. The method for manufacturing a disk-shaped glass substrate according to any one of 4. The fifth aspect of the present invention is to produce a disc-shaped glass substrate having a parallelism of 0.5 μm or less by polishing the two main surfaces of the ground disc-shaped glass base plate. The method for manufacturing a disk-shaped glass substrate according to. The thickness of the chamfered disc-shaped glass base plate other than the outer peripheral end surface and the chamfered surface is t1 mm.
The thickness of the outer peripheral end face of the chamfered disk-shaped glass base plate is t2 mm.
When
t1 × 0.15 <t2 <t1 × 0. The method for manufacturing a disk-shaped glass substrate according to any one of claims 1 to 6, wherein the method 4 is satisfied. The thickness of the outer peripheral end face of the chamfered disk-shaped glass base plate is t2 mm.
When the plate thickness other than the outer peripheral end surface and the chamfered surface of the disk-shaped glass substrate produced by the polishing is t3 mm.
Satisfy t3 × 0.5 <t2
The method for manufacturing a disk-shaped glass substrate according to any one of claims 1 to 7, wherein the disk-shaped glass substrate is manufactured. The grinding and the polishing are characterized in that the two main surfaces of the disk-shaped glass base plate are ground and polished with a allowance within a range in which at least a part of the chamfered surface remains. The method for manufacturing a disk-shaped glass substrate according to any one of claims 1 to 8 . The removal allowance by polishing is 10 to 150 μm .
The method for manufacturing a disk-shaped glass substrate according to any one of claims 1 to 9 , wherein the disk-shaped glass substrate is manufactured. The polishing is
The first polishing of polishing the two main surfaces of the ground disk-shaped glass base plate with the double-sided polishing device is performed.
The present invention includes performing a second polishing in which the two main surfaces of the disk-shaped glass base plate to which the first polishing has been performed are polished by the double-sided polishing device.
The invention according to any one of claims 1 to 10 , wherein the combination of the polishing pad and the polishing slurry applied to the double-sided polishing apparatus is different between the first polishing and the second polishing. How to manufacture a disk-shaped glass substrate.

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