Composite grindstone and centering processing device of optical lens

Abstract

The purpose of the present invention is to provide a composite grindstone and a centering device for an optical lens, the composite grindstone being capable of performing grinding such as rough grinding, intermediate grinding, and fine grinding with one grindstone, the ground surface obtained by the fine grinding being uniform and smooth, and the occurrence of white spot defects in the subsequent blackening (black layer formation) step being suppressed. A composite grindstone for grinding an optical lens is characterized in that the optical lens has an outer shape portion and a plane portion on the outer peripheral side, and the composite grindstone has a plurality of grinding portions including at least a first plane grinding portion and a second plane grinding portion. The first plane grinding part is used for carrying out rough grinding or medium grinding on the plane part of the optical lens, and the second plane grinding part is used for carrying out fine grinding on the plane part of the optical lens.

Description

Technical Field

[0001] The utility model relates to a composite grinding stone for grinding optical lenses.

[0002] In addition, the present invention also relates to a method for manufacturing an optical lens and a centering processing device using the same. Background Art

[0003] A vehicle-mounted camera unit is installed on the front or rear side of the vehicle as a system to assist the driver.

[0004] These in-vehicle camera units are widely used not only for visual assistance around the vehicle, but also for information on obstacles ahead, vehicles ahead, and vehicles behind, parking assistance, etc.

[0005] The optical lens used in such vehicle-mounted cameras is mostly composed of a first lens exposed to the outside and a plurality of sub-lenses located inside the first lens.

[0006] The first lens has a convex surface on its front surface, a flat surface portion on its back surface, and a concave surface portion on its inner peripheral side.

[0007] When such an optical lens is housed in a holder, an antireflection layer is formed on the flat surface portion by black coating or the like.

[0008] Therefore, if there is a pit-shaped defect on the ground surface of the flat portion, there is a problem that white spots appear on the black surface observed from the surface of the lens.

[0009] Conventionally, the grinding process for such optical lenses has used different grindstones for each grinding process, namely, rough grinding, intermediate grinding, and fine grinding. However, this requires replacement of the grindstones or requires multiple grinding devices.

[0010] Patent Document 1 discloses a tandem grindstone having a first abrasive layer of grit size #270 and a second abrasive layer of grit size #400. However, the purpose of the tandem grindstone is to speed up the processing of lenses with large processing margins, such as molded lenses, and is not intended to improve the processing quality of the flat surface portion of an optical lens.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-90467 Utility Model Content

[0014] Technical problems to be solved by utility models

[0015] The present invention aims to provide a composite grindstone, a method for manufacturing an optical lens using the same, and a centering processing device. The composite grindstone can perform grinding processes such as rough grinding, intermediate grinding, and fine grinding with a single grindstone, and the ground surface obtained by fine grinding is uniform and smooth, which can suppress the occurrence of white spot defects in the subsequent black coating (forming a black layer) process.

[0016] Solutions for solving technical problems

[0017] The composite grinding stone of the present invention is a composite grinding stone for grinding an optical lens, characterized in that the optical lens has an outer shape portion and a flat portion on the outer peripheral side, the composite grinding stone has a plurality of grinding portions, and the plurality of grinding portions include at least a first flat grinding portion and a second flat grinding portion, the first flat grinding portion performs rough grinding or intermediate grinding on the flat portion of the optical lens, and the second flat grinding portion performs fine grinding on the flat portion of the optical lens.

[0018] Here, for rough grinding or medium grinding, it is preferable to use a grinding stone with a grain size of #80 to #500. For fine grinding, a grinding stone finer than the rough grinding and medium grinding may be used, for example, a grinding stone with a grain size of #500 to #1200.

[0019] Here, the composite grindstone according to the present invention is characterized in that it is intended for grinding an optical lens having a flat surface portion on its back surface.

[0020] In the present invention, the composite grindstone preferably further comprises a first outer shape grinding portion and / or a second outer shape grinding portion, wherein the first outer shape grinding portion performs rough grinding or medium grinding on the outer shape portion of the optical lens, and the second outer shape grinding portion performs fine grinding on the outer shape portion of the optical lens.

[0021] In the present invention, the first surface grinding portion and / or the second surface grinding portion may also include a traverse grinding portion, and a tool-relief recess may be provided on the inner circumference of the traverse grinding portion.

[0022] Here, the traverse grinding section refers to grinding while the horizontal grinding surface of the rotating grindstone is traversed (transversely moved) along the flat surface of the optical lens. It is opposite to the press grinding in which the grinding surface of the grindstone is pressed against the surface to be ground of the optical lens.

[0023] Therefore, if the composite grindstone has a relief recess formed on the inner peripheral side in the direction in which the traverse grinding portion moves relative to the optical lens, grinding powder is easily swept into the relief recess, making it easier to supply grinding water to the grinding surface.

[0024] The present invention relates to a method for manufacturing an optical lens using the composite grindstone described in any one of the first to third aspects, characterized in that after rough grinding or intermediate grinding is performed on the flat surface portion of the optical lens using a first surface grinding unit, fine grinding is performed on the flat surface portion of the optical lens using a second surface grinding unit, thereby suppressing the generation of white spots when a black layer is subsequently formed on the flat surface portion.

[0025] In addition, the centering processing device involved in the present invention is characterized in that it comprises: a wheel grindstone subjected to rotation control, which is composed of a composite grindstone according to any one of the first to third aspects; a position control component for the feed direction X axis of the wheel grindstone and the Y axis orthogonal to the feed direction; and a holding component for clamping the optical lens.

[0026] Effect of utility model

[0027] The composite grinding stone of the utility model can be used to perform a series of grinding processes of rough grinding, intermediate grinding and fine grinding of an optical lens.

[0028] In particular, the finishing quality of the flat surface portion of the optical lens is improved, and a defect called frosting, in which white spots are generated on the coated surface in the subsequent black coating step, can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A configuration example of an optical lens centering apparatus using the composite grindstone according to the present invention as a wheel grindstone is shown. Figure 1 (a) shows a holding member of an optical lens, Figure 1 (b) schematically shows a state in which the optical lens is rotationally controlled and ground with a composite grindstone.

[0030] Figure 2 (a) shows the appearance of a compound grindstone (wheel grindstone), Figure 2 (b) shows its main view, Figure 2 (c) shows a cross-sectional view along line AA.

[0031] Figure 3 (a) Figure 3 (b) shows the process of performing rough grinding or medium grinding of the flat surface portion of the optical lens. Figure 3 (c) shows the flow of rough grinding or intermediate grinding of the outer shape portion on the outer periphery side of the optical lens and chamfer grinding of the upper surface side.

[0032] Figure 4 (a)~ Figure 4 (c) shows the process of fine grinding of the flat surface portion of the optical lens.

[0033] Figure 5 In Example 2, Figure 5 (a) Figure 5 (b) shows an example of rough grinding or medium grinding of the flat surface portion of the optical lens by traverse grinding. Figure 5 (c) shows an example of chamfering of the outer shape portion on the outer periphery side and the upper surface side of the optical lens.

[0034] Figure 6 (a)~ Figure 6 (c) shows an example of finish grinding of the flat surface portion of the optical lens by traverse grinding.

[0035] Figure 7 In the embodiment 3, an example of a composite grindstone is shown in which the first surface grinding portion (rough grinding, medium grinding) and the second surface grinding portion (finish grinding) are arranged upside down in contrast to the embodiment 1.

[0036] Figure 8 Examples of micrographs of a surface rough-ground with a grit size of #400 and a surface fine-ground with a grit size of #800 are shown.

[0037] Description of Reference Numerals

[0038] 1: Optical lens

[0039] 1a: Appearance

[0040] 1b: Flat surface

[0041] 10: Compound grinding stone (wheel grinding stone)

[0042] 11: Wheel

[0043] 11a: Mounting hole

[0044] 20: Grinding department

[0045] 21a: First surface grinding part

[0046] 21b: First outer shape grinding part

[0047] 21c: Chamfer grinding section

[0048] 22a: Second surface grinding portion. DETAILED DESCRIPTION

[0049] The purpose of the utility model is to perform centering processing of an optical lens, and it is characterized in that a rough grinding or intermediate grinding portion and a fine grinding portion are compositely formed in one grinding stone as a grinding stone used when fine grinding is performed after rough grinding and intermediate grinding, especially in order to suppress the generation of white spots when a black layer is formed on the flat surface portion of the optical lens in a subsequent process.

[0050] Therefore, the composite grinding stone of the present invention is not limited in structure as long as it can achieve the above-mentioned purpose.

[0051] Figure 1 1 shows a configuration example of an optical lens centering apparatus using the composite grindstone 10 according to the present invention.

[0052] As the composite grinding stone 10, Figure 2 An example of a wheel-type grindstone of the wheel type shown will be described.

[0053] The optical lens holding member adopts a bell-shaped clamping structure composed of a support portion 2 on the lower side of the optical lens 1 and a clamp 3 descending from the upper side.

[0054] exist Figure 1 In the state shown in (b), the holding member is rotated and the clamped state of the optical lens is centered.

[0055] Thereafter, the optical lens is subjected to grinding processing by the rotating composite grindstone 10 while the rotation of the optical lens is controlled.

[0056] Therefore, in the rotation mechanism of the composite grinding stone 10, the X-axis direction and the Y-axis direction are position-controlled. Figure 1 In (b), at least the horizontal direction is the feed direction of the grinding stone, and the Y-axis direction is perpendicular to the up-down direction.

[0057] It should be noted that Figure 1 The centering processing device shown is an example of clamping the optical lens in the vertical direction, but it can also clamp the optical lens in the horizontal direction.

[0058] Figure 2 2 shows an example of the shape of the composite grinding stone 10 as Example 1.

[0059] This embodiment includes a wheel portion 11 having a mounting hole 11a at its center and a grinding portion 20 on its outer peripheral surface.

[0060] An enlarged view of the grinding portion 20 is shown in FIG. Figure 3 middle.

[0061] The grinding portion 20 is an electrodeposited grindstone in which abrasive grains are fixed to a base metal by plating.

[0062] exist Figure 3 In (a), the grinding portion is divided by the dotted line shown in the horizontal direction. Abrasive grains for rough grinding are electrodeposited on the outer peripheral surface of the upper R1 region, and abrasive grains for fine grinding are electrodeposited on the outer peripheral surface of the lower R2 region.

[0063] The optical lens 1 has a convex upper surface, a concave portion in the center of the lower surface, a flat portion 1 b on the outer periphery, and a circular outer portion 1 a on the side surface.

[0064] The optical lens 1 to which the present invention is directed is an optical lens having a flat surface portion on its lower surface and having a black layer formed by black coating or the like in a subsequent step after grinding.

[0065] Next, the flow of the grinding process will be described.

[0066] like Figure 3 As shown in (a), the R1 area for rough grinding has a first plane grinding portion 21a consisting of a horizontal surface for rough grinding the plane portion 1b of the optical lens 1 and a first outer shape grinding portion 21b in a vertical direction for rough grinding the outer shape portion 1a on the outer peripheral side of the optical lens 1, and has a chamfering grinding portion 21c for chamfering the upper side (convex portion side) of the outer shape portion 1a as needed.

[0067] The chamfer shape may be a C-chamfer or a stepped chamfer shape.

[0068] The composite grinding stone 10 moves forward along the X-axis direction relative to the optical lens 1 which is held in rotation. Figure 3 As shown in (b) of FIG. 1 , the first surface grinding portion 21 a of the rotationally controlled grinding stone is pressed from below in the Y-axis direction, thereby performing rough grinding.

[0069] This ground surface is denoted as 1b-g1.

[0070] Next, after the composite grinding stone 10 is retracted, Figure 3 As shown in (c), the first outer shape grinding portion 21 b and the chamfer grinding portion 21 c perform outer shape grinding and chamfer grinding.

[0071] This ground surface is denoted as 1a-g1.

[0072] Next, finish grinding will be described.

[0073] The R2 region of the composite grindstone 10 has a horizontal second surface grinding portion 22 a for finish grinding.

[0074] It should be noted that a second outer shape grinding portion 22 b in the vertical direction may be provided as needed.

[0075] The second outer shape grinding portion 22 b can be used when it is necessary to perform finish grinding on the outer shape portion 1 a of the optical lens.

[0076] exist Figure 4 In the embodiment shown, Figure 4As shown in (a), the composite grinding stone 10 is advanced in the X-axis direction, and as shown in Figure 4 As shown in (b), the second surface grinding portion 22 a is pressed against the flat surface portion of the optical lens 1 while the optical lens 1 and the composite grindstone 10 are rotated relative to each other.

[0077] As a result, the flat surface portion becomes the finish-ground ground surface 1b-g2.

[0078] By using the composite grindstone 10 according to the present invention, rough grinding and fine grinding can be performed continuously with one composite grindstone.

[0079] The shape of the grinding portion 20 of the composite grindstone of Example 2 is shown in FIG. Figure 5 middle.

[0080] Description of the same parts as those in Example 1 will be omitted, and the description will focus on the differences.

[0081] In this example, a first surface ground portion 21a in the R1 region has a slightly lowered stepped ground portion 21d at its outer peripheral end, and a second surface ground portion 22a in the R2 region is a traverse ground portion with a recessed relief recess 22c formed inside.

[0082] Rough grinding is as follows Figure 5 As shown in (a) of FIG. 1 , the rotating composite grindstone 10 is caused to cut into the flat surface portion 1 b of the optical lens 1 while performing traverse grinding.

[0083] Figure 5 (b) shows a state after the rough grinding is completed. Due to the step-ground portion 21 d , an annular protrusion 1 c remains on the flat surface of the optical lens.

[0084] This is done to suppress chipping (notch) at the boundary between the flat surface portion 1 b and the inner concave surface portion.

[0085] Figure 5 (c) shows a state where the outer portion 1 a is being rough-ground and chamfer-ground.

[0086] It should be noted that, if necessary, the outer portion 1a may be ground first and then the outer portion 1a may be ground. Figure 5 (a) Figure 5 (b) shows the traverse grinding.

[0087] Then, if Figure 6 As shown in (a) of FIG. 2 , the composite grindstone 10 is advanced so that the second surface grinding portion (traverse grinding portion) 22 a moves in the traverse direction.

[0088] At this time, the grinding chips easily fall into the relief recess 22c, and the inflow of grinding water and the like is also improved.

[0089] Furthermore, since the annular protrusion 1 c is ground in the finish grinding stage, the occurrence of chipping is reduced.

[0090] Figure 7 An example of the composite grinding stone 10 according to the third embodiment is shown in FIG.

[0091] This embodiment 3 is as follows: Figure 7 As shown in (b), the R1 region for rough grinding and intermediate grinding is located below the dotted line, and the R2 region for finish grinding is located above the dotted line. Abrasive grains are fixed to the base metal by electrodeposition.

[0092] In this case, Figure 7 As shown in (c), a relief recess 22 c may be formed on the inner peripheral side of the second surface ground portion 22 a and traverse grinding may be performed.

[0093] The photograph of the flat surface portion 1b of the optical lens 1 which was rough ground with #400 and then fine ground with #800 using the composite grindstone 10 according to the present invention is shown in FIG. Figure 8 middle.

[0094] The surface roughness of the ground surface of No. 400 was Ra: 1.2074 μm, Rz: 27.2743 μm, and a surface chipping with a size of 76 μm was observed.

[0095] In contrast, the surface roughness of the ground surface of #800 was reduced to Ra: 0.8928 μm and Rz: 15.1845 μm, and the occurrence of chipping was also reduced.

[0096] From this, it is inferred that when finish grinding is performed with #800, white spot defects can be suppressed during black coating in the subsequent step.

Claims

1. A composite grinding stone for grinding optical lenses, characterized in that: The optical lens has an outer peripheral portion and a flat portion. The composite grinding stone has a plurality of grinding parts. The plurality of grinding parts include at least a first surface grinding part for performing rough grinding or intermediate grinding on a flat surface portion of the optical lens and a second surface grinding part for performing fine grinding on the flat surface portion of the optical lens.

2. The composite grinding stone according to claim 1, characterized in that The composite grindstone further comprises a first outer shape grinding portion and / or a second outer shape grinding portion, wherein the first outer shape grinding portion performs rough grinding or intermediate grinding on the outer shape portion of the optical lens, and the second outer shape grinding portion performs fine grinding on the outer shape portion of the optical lens.

3. The composite grinding stone according to claim 1, wherein The first surface grinding portion and / or the second surface grinding portion includes a traverse grinding portion, and a relief recess is provided on the inner circumference of the traverse grinding portion.

4. A centering processing device for an optical lens, characterized in that: have: A wheel-type grinding stone subjected to rotational control, comprising the composite grinding stone according to any one of claims 1 to 3; Position control components for the X-axis of the wheel grindstone's feed direction and the Y-axis perpendicular to the feed direction; as well as Retaining component, clamping the optical lens.

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