Patent ID: 12253736

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the disclosure will be described with reference to the drawings.

FIG.2is a view schematically illustrating a plane and a cross-section of a lens spacer according to an embodiment of the disclosure.

Referring toFIG.2, in the disclosure, a lens spacer100uses copper or a copper alloy as a base material110for the spacer. The lens spacer100may further include the base material110and a coating layer for protecting substantially the entire surface of the base material, but the coating layer is not illustrated herein for convenience of illustration. Therefore, the lens spacer100in the disclosure may refer to an article before the surface film is formed, and may refer to an article after the surface film is formed.

The base material110of the spacer is a ring-shaped base material having a predetermined thickness t and having a hollow part in the center. In addition, in the disclosure, the outer shape of the spacer is illustrated as a circular ring, but other shapes such as a square ring can also be applied. As will be described later, the hollow part is formed by etching. In the specification of the disclosure, this region is a groove penetrated by etching and is referred to as a penetration etching region A.

In the disclosure, the penetration etching region A may be, for example, a circle having a predetermined diameter dA, but is not limited thereto. A half-etching region B having a predetermined width wBextends along the outer circumference of the penetration etching region A, followed by a non-etching region having a predetermined width. Unless otherwise stated, the quantitative values referred to in the specification of the disclosure refer to average values.

Half-etching is an etching method which reduces the thickness of the base material. Unlike machining, etching cannot uniformly and accurately control the thickness of the resulting base material depending on its position due to factors that are difficult to control, such as local non-uniformity of etching solution composition and solute diffusion problems due to position. For example, in machining, the inclined surface can be finely processed at a predetermined angle, but in etching, the inclination angle may change locally depending on the etching position. In the disclosure, a region having a structural characteristic due to the application of such an etching process is referred to as a half-etching region.

InFIG.2, the width wBof the half-etching region B is larger than the thickness t of the base material. Preferably, the width wBmay be 2 times or more, 3 times or more, 4 times or more, or 5 times or more the thickness t. The width wBof the half-etching region sufficiently separates a start portion of the half-etching region from a hollow edge to minimize the effect of the start edge on reflection.

In addition, the width wBof the half-etching region B is preferably less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, or less than 20% of the entire circumference width wsof the spacer.

Referring toFIG.2, the penetration etching region, the half-etching region, and the non-etching region are connected in a stepwise manner. However, in the disclosure, this connection structure is merely an example.

FIG.3is a view schematically illustrating a cross-section of a lens spacer according to another embodiment of the disclosure.FIG.3illustrates only a spacer on the left side with reference to the penetration etching area A.

Referring toFIG.3, the half-etching region B is divided into a plurality of sub-regions B1, B2, and B3. The sub-regions include a slow slope region B2having a gentle slope and fast slope regions B1and B3having a steeper slope, and the width wBof the slow slope region B2is larger than the respective widths wB2or wB3of the fast slope regions B1and B3and occupies most of the width of the half-etching region. In the disclosure, the width wB2of the slow slope may be 2 times or more, 3 times or more, 4 times or more, or 5 times or more the thickness t of the spacer base material. In addition, the width wB2of the slow slope is preferably less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, or less than 20% of the entire circumference width wsof the spacer.

Meanwhile, in the drawings, the first slope region and the slow slope region are represented by straight lines, respectively, but this is a schematic representation of the average slope, and each region can form a curved shape partially or entirely. In the disclosure, the average inclination angle of the slow slope may be 25° or less, 20° or less, 15° or less, 10° or less, or 5° or less with reference to the surface of the base material.

The wide slow slope region in such an inclined structure substantially reduces the thickness occupied by the fast slope region adjacent to the penetration etching region A in the entire thickness t of the spacer base material. Accordingly, the thickness of the fast slope region adjacent to the penetration etching region A of the spacer is significantly reduced to be smaller than the base material thickness t. For example, the thickness of the spacer edge on the hollow part side may be less than 80%, less than 70%, less than 60%, or less than 50% with respect to the total thickness t. As described above, the disclosure has the effect of substantially reducing the thickness of the spacer at the hollow edge part. In addition, although the thickness of the spacer hollow edge is substantially reduced, the thickness of the spacer body is not reduced. That is, the spacer maintains the original role and rigidity of separating the lens module.

FIG.4is a view schematically illustrating a cross-section of a lens spacer according to still another embodiment of the disclosure.

Referring toFIG.4, the entire section wBof the half-etching region substantially includes a slow slope region without a region being regarded as a fast slope region.

A structure of the lens spacer with reference toFIG.2toFIG.4above, but the lens spacer of the disclosure may further include a surface coating layer formed on the surface of a copper or copper alloy base material. The surface coating layer may preferably be a black copper oxide layer. More preferably, the surface coating layer may be a black copper oxide layer having a needle-shaped structure. The black copper oxide layer on the surface of the spacer base material may be formed by an appropriate method. The method for manufacturing a black copper oxide layer having a needle-shaped structure disclosed in Registered U.S. Pat. No. 1,173,835 of the present applicant may be applied. For example, after heating an aqueous solution of caustic soda (NaOH) and chlorite soda (NaClO2) in a weight ratio of 9:1 to a temperature of 70 to 90° C., a black copper oxide layer having a needle-shaped structure may be produced on the surface by immersing the spacer for 5 to 15 minutes.

The slow slope structure of the disclosure is a structure which is difficult to be introduced by general machining such as punching and perforation. The thickness of a lens spacer used in a mobile terminal such as a mobile phone camera module is gradually decreasing, and it is more difficult to incline the edge of the spacer having a thickness of 50 μm or less or 35 μm or less by mechanical processing. In the disclosure, the inclined surface structure including the slow slope structure is introduced by a half-etching process. This will be described later.

FIG.5is a view schematically illustrating a lens spacer manufacturing process according to an embodiment of the disclosure.

Referring toFIG.5, a first etching mask pattern32having a first opening having a predetermined width D1for defining the penetration etching region A is formed on one surface of a copper plate or a copper foil10having a predetermined thickness, and a second etching mask pattern34having a second opening having a predetermined width D2for defining the half-etching region B is formed on the other surface thereof.

As illustrated above, the width D2of the mask pattern defining the half-etching region is greater than the width D2of the mask pattern defining the penetration etching region. In the disclosure, the opening widths D1and D2are for defining the penetration etching region and the half-etching region, respectively, but they do not match each other and may be empirically set according to the etching conditions.

In the disclosure, the first etching mask pattern32and the second etching mask pattern34may be formed by photoresist coating, photosensitizing, and exposure steps. Of course, any form of mask which can function as an etching mask may be used.

Next, spray nozzles20are arranged above and below the copper plate10on which the first mask pattern and the second mask pattern are formed, and the etching solution is sprayed. The etching solution corrodes the exposed portion of the copper plate10to form a penetration etching region and a half-etching region.

In the disclosure, the etching solution includes ferric chloride or copper (II) chloride, which are highly corrosive, as main components and may include hydrochloric acid and water. In addition, in the disclosure, the etching conditions may be appropriately selected in consideration of the etching profile so that the vicinity of the opening D1is penetrated and the vicinity of the opening D2is half-etched. In addition, the case where the first etching mask and the second etching mask are formed and the penetration etching region and the half-etching region are in-situ formed in one etching step has been described above, but of course, the etching process using the first etching mask pattern and the etching process using the second etching mask pattern may be sequentially applied.

When the etching process has completed, the first etching mask pattern and the second etching mask pattern on the copper plate surface may be removed by suitable methods such as stripping or ashing.

FIG.6is a view schematically illustrating a lens spacer manufacturing process according to another embodiment of the disclosure.

Referring toFIG.6, as inFIG.5, the first mask pattern32and the second mask pattern34are formed on the surface of the copper plate10. However, unlikeFIG.5, the etching solution is sprayed from the upper nozzle20, and the back surface of the copper plate is not provided with a nozzle for supplying the etching solution. However, after the etching solution penetrates the copper plate10to form a through-hole, the etching solution is supplied to the back surface to partially etch the back surface.

FIG.7is a view schematically illustrating a lens spacer manufacturing process according to still another embodiment of the disclosure.

As inFIG.5andFIG.6, the first mask pattern32and the second mask pattern34are formed on the surface of the copper plate10. Meanwhile, a protective film36is laminated on the surface of the second mask pattern34. A random film having etching resistance against an etching solution may be used as the protective film. For example, an adhesive tape or the like may be used as the protective film. For example, the product name ST-5535 of Daehyun ST may be used. The protective film36may provide resistance against the flow of the etching solution even after penetrating the copper plate to prevent the back surface portion of the copper plate from being rapidly etched.

MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

A photoresist is applied to the surface of a copper plate having a thickness of about 30 μm and a diameter of 6 mm, and is exposed and developed to form the mask pattern illustrated inFIG.5toFIG.7. The etching solution (ferric chloride concentration 40-43%) is sprayed through a spray nozzle at a flow rate of 2 LPM for 1 minute. The manufactured spacer is embedded and cured in an epoxy resin and the cross-section of the spacer is observed.

For comparison, a sample is prepared by performing only penetration etching without half-etching. In this case, the opening width of the first mask pattern and the opening width of the second mask pattern are made to be identical.

FIG.8AtoFIG.8Dare optical micrographs of left and right, with reference to a hollow part, cross-sections of a spacer manufactured according to the present embodiment. As shown inFIG.8AandFIG.8B, a fast slope region B1at the start portion of the half-etching region, a fast slope region B3at the end portion of the half-etching region, and a slow slope region having a gentle slope and formed therebetween may be confirmed. In addition, it can be seen that due to the very wide slow slope region, the thickness of the fast slope region B3at the end of the half-etching region is reduced to a level of 15 μm or less. In addition, from the photograph, it can be seen that the surface of the half-etching region has an uneven and rough surface, and the inclined profile does not show a smooth straight line.

Meanwhile,FIGS.8C and8Dare photographs of the cross-section of a spacer of a comparative example. It can be seen that the thickness of the hollow side edge of the spacer reaches about 30 μm.

Embodiment 2

A spacer is manufactured by the same method as in Embodiment 1 except that the thickness of the copper plate is about 20 μm, and the cross-section thereof is observed.

FIG.9AandFIG.9Bare optical micrographs of the cross-section of the spacer manufactured according to the present embodiment, andFIG.9CandFIG.9Dare optical micrographs of the cross-section of the spacer manufactured according to the comparative example. It can be seen that most of the half-etching region consists of a slow slope region, and the edge part of the end portion of the half-etching region forms a narrow-width fast slope region. However, in the present embodiment, the fast slope region does not appear to be identified at the start portion of the half-etching region.

Embodiment 3

A spacer is manufactured by the same method as in Embodiment 1 except that the thickness of the copper plate is about 25 μm, and the cross-section thereof is observed.FIG.10AandFIG.10Bare optical micrographs of the cross-section of the spacer manufactured according to the present embodiment, andFIG.10CandFIG.10Dare optical micrographs of the cross-section of the spacer manufactured according to the comparative example. As described with reference toFIG.8andFIG.9, also in the present embodiment, it is possible to confirm the decrease in the thickness of the slow slope region and the fast slope region at the end portion of the half-etching region.

INDUSTRIAL APPLICABILITY

The disclosure is applicable to a camera lens module, and is particularly useful for a camera lens module of a mobile phone.