KR101034183B1 - Apparatus and method for measuring displacement and tilt of lens module - Google Patents

Abstract

The present invention can measure both the tilt value and the displacement amount of the lens module with one displacement sensor, and the displacement amount and tilt measuring apparatus and method of the lens module that can obtain a very precise tilt value while significantly reducing the overall tilt value measurement time A jig for fixing a lens barrel; A displacement sensor for irradiating light to the lens barrel in a direction away from a lens center to sense a distance to the irradiated point; And a rotation motor for rotating the lens barrel about an axis of the lens so that light is irradiated to at least two points of the lens barrel.

Displacement Sensor, Lens, Module, Displacement, Tilt

Description

Apparatus and method for measuring displacement and tilt of lens module

The present invention relates to an apparatus and a method for measuring displacement and tilt of a lens module, and more particularly, in a lens module of a small optical system built in a mobile phone camera, etc., a lens capable of simultaneously measuring the degree of tilt of the lens with respect to the optical axis and the displacement of the lens. An apparatus and method for measuring displacement and tilt of a module.

In general, a lens module includes a plurality of lens arrays including an objective lens, a lens barrel for fixing the lens array, a charge coupled device (CCD) for obtaining image data from an optical signal obtained by the lens array, and a CMOS ( An image sensor such as Complementary Metal Oxide Semiconductor). Since the lens module is made of a small optical system, an error in the assembly process of the lens module greatly affects the performance of the camera.

Therefore, during the assembly process of the lens module, a tilt value, which is a degree of inclination with respect to the optical axis of the lens, is measured, and an error test is performed to determine whether the tilt value is within an allowable range. Such tilt measurement may be performed after the assembly of the camera module is completed or by analyzing an image captured by the camera module to determine whether the lens module is defective. However, the tilt measuring device as described above requires an unnecessary assembly process, and thus, efficiency is reduced in time and cost, and it is difficult to determine which component of the lens module is a problem.

The conventional tilt measuring apparatus presented as a solution to this is to use an autocollimeter, the tilt value of the lens module was measured by measuring the reflection angle of the light.

That is, as shown in FIG. 1, the conventional tilt measuring apparatus fixes the reflection mirror 102 in parallel with the lens barrel 101 on which the lens 103 is mounted, and uses the auto collimator 104 to fix the light. Was irradiated to the reflecting mirror 102 and the angle of the reflected light was measured. In this case, the difference Q between the incident angle and the reflection angle corresponds to the horizontal tilt of the lens module, which is proportional to the tilt value of the lens module.

However, the conventional tilt measuring device should be equipped with a reflecting mirror for reflecting light using an auto collimator which is an angle measuring device. Accordingly, not only the cost for the reflection mirror is increased, but also a long time is required to align the reflection mirror in parallel with the lens barrel.

In addition, the conventional tilt measuring device should be provided with a separate displacement sensor to measure the displacement of the lens module. Therefore, conventionally, in order to measure the tilt value and the displacement of the lens module, the auto collimator and the displacement sensor should be provided together or a separate displacement measurement device should be installed.

The present invention was created in order to solve the above-mentioned problems. Measurement and displacement of the lens module and tilt which can reduce the overall cost of the reflection mirror and the time required for the arrangement of the reflection mirror are not required. It is an object of the present invention to provide an apparatus and method.

In addition, the present invention can measure both the tilt value and the displacement amount of the lens module with a single displacement sensor, the displacement amount and tilt measuring device of the lens module to obtain a very precise tilt value while significantly reducing the overall tilt value measurement time And to provide a method.

The present invention to achieve the above object, the jig for fixing the lens barrel; A displacement sensor for irradiating light to the lens barrel in a direction away from a lens center to sense a distance to the irradiated point; And a rotation motor for rotating the lens barrel about an axis of the lens so that light is irradiated to at least two points of the lens barrel.

In addition, the rotary motor is connected to the jig is preferably rotated the jig.

In this case, the jig may include: an elastic pressing unit for positioning the lens barrel and absorbing vibration of the lens barrel.

In addition, the jig is preferably fixed to the lens barrel to be movable up and down.

In addition, the light is preferably a laser beam.

In this case, the laser beam is preferably a line scan type.

On the other hand, the present invention comprises the steps of the displacement sensor irradiating light to the lens barrel in a direction away from the lens center, and sensing the distance between the displacement sensor and the lens barrel irradiated with light at at least two points; Measuring a tilt value using the difference of the sensed distances; And a displacement sensor measuring the displacement amount of the lens while moving the lens barrel up and down.

In this case, the sensing step may include: rotating the lens barrel about an axis of the lens to sense the distance between the displacement sensor and the lens barrel at at least two points while the displacement sensor is fixed. It is preferable.

Displacement and tilt measurement apparatus and method of the lens module according to the present invention does not require a reflection mirror can reduce the cost for the reflection mirror and the time required for the arrangement of the reflection mirror.

In addition, the present invention is very useful because it is possible to measure both the tilt value and the displacement amount of the lens module with one displacement sensor.

In addition, the present invention can sense a plurality of points in a short time, it is possible to measure the precise tilt value and the displacement amount in a very short time.

Hereinafter, the technical configuration of the present invention according to the accompanying drawings in detail.

2 is a side view of the displacement and tilt measurement apparatus of the lens module according to an embodiment of the present invention, Figure 3 is a partially enlarged perspective view of Figure 2, Figure 4 is a partially enlarged perspective view of the FIG.

As shown in Figures 2 to 4, the displacement amount and tilt measurement apparatus 100 of the lens module according to the present invention comprises a jig 10, the displacement sensor 20, and the rotation motor 30.

The jig 10 fixes the lens barrel 40. The jig 10 is implemented in a chuck type, it is preferable to fix and detach the lens barrel 40.

The displacement sensor 20 irradiates the lens barrel 40 with light 50 to sense the distance to the irradiated point with the displacement sensor 20. The light 50 irradiated from the displacement sensor 20 is reflected by the lens barrel 40 and again sensed by the displacement sensor 20. That is, the displacement sensor 20 irradiates the light 50 to a point away from the center of the lens 41 of the upper surface of the lens barrel 40. As such, the displacement sensor 20 senses the distance between the displacement sensor 20 and the lens barrel 40.

As a result, the light 50 is incident and reflected on the surface of the lens barrel 40 to detect the distance between the displacement sensor 20 and the lens barrel 40. If the light 50 is directly irradiated to the lens 41, the light 50 is transmitted without being reflected due to the characteristics of the transparent lens 41. Therefore, the light 50 is directly irradiated to the lens barrel 40.

The rotary motor 30 rotates the lens barrel 40 about the center of the lens 41. Therefore, the displacement sensor 20 may irradiate light 50 to at least two points of the lens barrel 40 in a fixed state. As such, the displacement sensor 20 may rotate the lens barrel 40 in a fixed state to sense the distance between the displacement sensor 20 and the lens barrel 40 at a plurality of points.

That is, the displacement sensor 20 senses the distance between the displacement sensor 20 and the point P1 of the lens barrel 40 by irradiating the light 50 to one point P1 of the lens barrel 40. The lens barrel 40 is rotated about an axis of the lens 41. In this way, the light 50 is irradiated to another point P2 of the lens barrel 40 to sense the distance between the displacement sensor 20 and the other point P2 of the lens barrel 40. The distance of the other points P3 and P4 of the lens barrel is also sensed as described above.

The distances between the displacement sensor 20 and the lens barrel 40 sensed as described above are used as data for measuring the tilt value. The tilt value is a measure of how much the lens barrel 40 is tilted in the horizontal state and is proportional to the inclination. Therefore, the larger the tilt of the lens barrel 40, the larger the tilt value.

That is, the difference in the distances between the displacement sensor 20 and the lens barrel 40 becomes data indicating how much the lens barrel 40 is tilted in the horizontal state. If the lens barrel 40 is in a completely horizontal state, the distances between the displacement sensor 20 and the lens barrel 40 sensed by the displacement sensor 20 should all be the same. In this case, the difference between the respective distances is zero and the tilt value is zero.

In this case, the more the distance data between the displacement sensor 20 and the lens barrel 40 in which the displacement sensor 20 irradiates the light 50 to the lens barrel 40, the higher the precision of the tilt value measurement.

Figure 5 shows a schematic configuration of a tilt measuring device according to an embodiment of the present invention.

Referring to the present invention in more detail, as shown in FIG. 5, the displacement sensor 20 irradiates the light 50 to the upper surface of the lens barrel 40 away from the center of the lens 41 by a displacement sensor. The distance d1 between the 20 and the lens barrel 40 is sensed. Thereafter, the lens barrel 40 is rotated about the center of the lens 41, the displacement sensor 20 is irradiated with light 50, the distance between the displacement sensor 20 and the lens barrel 40. sense (d2).

In this case, the tilt value may be measured through the difference between the separation distances d1 and d2 at two different points of the lens barrel 40. That is, since the absolute value of (d2-d1) is proportional to the tilt value, it can be used as data for determining the degree of inclination of the lens barrel 40.

Therefore, the displacement amount and tilt measurement apparatus 100 of the lens module according to the present invention does not require a separate reflection mirror. In addition, not only the tilt value of the lens module may be easily measured by one displacement sensor 20, but the displacement sensor 20 may be used as a displacement measurement unit of the lens module. For reference, the lens module undergoes various tests in the manufacturing process, and the tests include a tilt test, a hysteresis test and a displacement and speed test during driving.

As a result, the displacement amount and tilt measurement apparatus 100 of the lens module according to the present invention do not need to include a separate reflection mirror, an auto collimator, and the like, and all the tilt and displacement amounts of the lens module with one displacement sensor. There is a measurable advantage.

On the other hand, the rotary motor 30 is preferably connected to the jig 10 to rotate the jig 10.

In this case, the jig 10 may further include an elastic pressing unit 11. The elastic pressing unit 11 serves to hold the position of the lens barrel 40 and to absorb the vibration of the lens barrel 40. Therefore, the jig 10 is prevented from vibrating up, down, left, and right when rotating by the rotary motor 30.

In addition, the jig 10 is preferably fixed to the lens barrel 40 to move up and down. Therefore, not only the displacement amount of the lens barrel 40 can be measured, but also all the tilt values when the lens barrel 40 is driven can be measured.

In addition, the light may be a laser beam. In this case, the laser beam is preferably a line scan type. If the laser beam is implemented as a line scan type, the average value may be used after sensing a plurality of points. Therefore, the measurement accuracy is higher than that of the point scan type.

6 is a front view of the displacement and tilt measurement apparatus of the lens module according to another embodiment of the present invention.

As shown in FIG. 6, the displacement and tilt measurement apparatus 100 of the lens module according to the present invention may also include a guide unit 90. The guide unit 90 horizontally transfers the displacement sensor 20, and transfers the displacement sensor 20 to the upper portion of the lens module 40 or the displacement sensor 20 to the lens module 40. Away from the top of the. Therefore, maintenance and replacement of the equipment is easy, and it provides convenience for the displacement amount and tilt measurement of the lens module.

7 is a flowchart illustrating a method of measuring displacement and tilt of a lens module according to the present invention.

As shown in FIG. 7, the method for measuring displacement and tilt of the lens module according to the present invention includes sensing a distance between the displacement sensor 20 and the lens barrel 40 (S1) and measuring a tilt value. (S3) and measuring the displacement amount (S4).

In step S1, the displacement sensor 20 irradiates light to the lens barrel 40. That is, the displacement sensor 20 irradiates light to a point away from the center of the lens 41 of the upper surface of the lens barrel 40. The displacement sensor 20 senses the distance between the displacement sensor 20 and the lens barrel through irradiation of light. In addition, the displacement sensor 20 senses the distance by irradiating light to another point of the lens module 40 in the same manner. As such, the displacement sensor 20 senses the distance by irradiating light to at least two points of the lens barrel 40.

In this case, the light may be incident and reflected on the surface of the lens barrel 40 to detect the distance between the displacement sensor 20 and the lens barrel 40. If the light is directly irradiated to the lens 41, the light is transmitted without being reflected due to the characteristics of the transparent lens. Thus, the light is directed to the lens barrel 40 directly.

In step S3, the tilt value is measured using the difference between the distances between the displacement sensor 20 and the lens barrel 40 sensed in step S1. The tilt value is a measure of how much the lens barrel 40 is tilted in the horizontal state and is proportional to the inclination. Therefore, the larger the tilt of the lens barrel 40, the larger the tilt value.

In the step S4, the displacement sensor 20 measures the displacement of the lens 41. In order for the displacement sensor 20 to measure the displacement amount, the lens barrel 40 is moved up and down. In this case, it is preferable to implement the jig 10 for fixing the lens barrel 40 to be movable up and down.

As such, through one displacement sensor 20, both the displacement amount and the tilt of the lens module can be measured.

On the other hand, the step (S1) may further include a step (S2) for rotating the lens barrel 40 around the lens 41 center.

In step S2, the lens barrel 40 is rotated about an axis of the lens 41, and the displacement sensor 20 irradiates light to at least two points of the lens barrel 40. Therefore, the distance between the displacement sensor 20 and the lens barrel 40 can be sensed at two or more points. In this case, the rotation motor 30 allows the displacement sensor 20 to rotate the entire lens barrel 40 in a state fixed to the upper portion of the lens barrel 40.

In order for the displacement sensor 20 to irradiate light to at least two points of the lens barrel 40, a plurality of displacement sensors 20 may be installed or a method of transferring or rotating the displacement sensors 20 may be adopted. However, if a plurality of displacement sensors 20 are installed, the overall cost increases and the efficiency thereof is not effective. If the displacement sensor 20 is driven, the error increases in the sensing process.

For this reason, the displacement sensor 20 is fixed, it is preferable to adopt a method for rotating the entire lens barrel 40 so that light is irradiated to various points of the lens barrel 40.

In addition, the sensing points are preferably located on a concentric circle of the lens barrel 40 which is centered on the lens 41. More preferably, four points are sensed at intervals of 90 ° on the concentric circles of the lens barrel 40 centered on the lens 41. Therefore, it is possible to accurately measure the tilt values with respect to the X-axis and the Y-axis (with the lens center as the origin) of the lens barrel 40 relatively few times.

On the other hand, the step of measuring the tilt value (S3) further comprises the step of measuring the initial tilt value (T1), measuring the driving tilt value (T2), and measuring the total tilt value (T3) can do.

8 is a graph showing tilt values according to driving of the lens barrel.

Referring to FIG. 8, the initial tilt value T1 is a tilt value measured at the reference height. The reference height refers to the highest or lowest point when the lens is raised and lowered.

The driving tilt value T2 is obtained through the difference between the maximum tilt value and the initial tilt value T1 among the tilt values measured while moving the lens barrel 40 vertically. That is, each point in FIG. 8 is a tilt value measured at various heights by moving the lens barrel 40 vertically, and the driving tilt value T2 is the maximum tilt representing the largest displacement with the initial tilt value T1. The difference in value. The driving tilt value T2 is a data for identifying the tilt generated by the lens module during the focusing driving.

The comprehensive tilt value T3 represents the maximum tilt value when the tilt value is 0 as a reference. That is, the total tilt value T3 represents the maximum tilt value that the lens can have when the lens is moved relative to the complete horizontal state.

In this case, the initial tilt value T1 can be obtained through the following relational expression.

Here, Tx represents the X-axis tilt value and Ty represents the Y-axis tilt value. Hx is the distance to the displacement sensor with respect to the X axis, Hy is the distance to the displacement sensor with respect to the Y axis, and D is the diameter of the circle.

The X-axis tilt value Tx is the inclination of the lens module with respect to the X axis in a two-dimensional coordinate system having the center of the lens 41 as the origin, and the Y-axis tilt value Ty is the origin of the lens 41 as the origin. The slope of the lens module with respect to the Y axis in a two-dimensional coordinate system.

In the equation for obtaining the X-axis tilt value (Tx), the tangent (TAN) value of the inclination angle of the lens barrel 40 is the value obtained by dividing the distance (Hx) to the displacement sensor with respect to the X-axis by the diameter (D) of the circle. Therefore, the inclination angle of the lens barrel 40 is obtained using the arc tangent (ATAN) value. Since the obtained value is a radian value, the degree value is obtained by multiplying (360 ÷ (2π)). Multiply this value by 60 to get the X-axis tilt value (Tx), which is the angle value in minutes (').

In addition, in the equation for obtaining the Y-axis tilt value Ty, the tangent TAN value of the inclination angle of the lens barrel 40 is obtained by dividing the distance Hy to the displacement sensor with respect to the Y-axis by the diameter D of the circle. Value, the inclination angle of the lens barrel 40 is obtained using an arc tangent (ATAN) value. Since the obtained value is a radian value, the degree value is obtained by multiplying (360 ÷ (2π)). Multiplying this value by 60 yields the Y-axis tilt value Ty, an angle value in minutes.

On the other hand, the driving tilt value T2 can be obtained through the following relational expression.

Here, Mx is the X-axis maximum tilt value and My is the Y-axis maximum tilt value.

On the other hand, the light is preferably a line scan type. When the light is implemented as a line scan type, the average value may be used after sensing several points. Therefore, the measurement accuracy is higher than that of the point scan type.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and any person skilled in the art to which the present invention pertains may have various modifications and equivalent other embodiments. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a cross-sectional view showing a schematic configuration of a tilt measuring device of a conventional lens module,

2 is a side view of the displacement and tilt measurement apparatus of the lens module according to an embodiment of the present invention,

3 is a partially enlarged perspective view of FIG. 2;

4 is a partially enlarged perspective view of FIG. 3;

5 shows a schematic configuration of a tilt measuring device according to an embodiment of the present invention,

6 is a front view of the displacement and tilt measurement apparatus of the lens module according to another embodiment of the present invention,

7 is a flow chart of the displacement and tilt measurement method of the lens module according to the present invention.

8 is a graph showing a tilt value according to the driving of the lens barrel.

<Description of the symbols for the main parts of the drawings>

10: jig 11: elastic pressing unit

20: displacement sensor 30: rotating motor

40: lens barrel 41: lens

50: light 90: guide part

100: displacement and tilt measuring device

Claims (10)

delete delete Jig for fixing the lens barrel; A displacement sensor for irradiating light to the lens barrel in a direction away from a lens center to sense a distance to the irradiated point; And A rotation motor for rotating the lens barrel about an axis of the lens such that light is irradiated to at least two points of the lens barrel; Including The jig further comprises an elastic pressing unit for holding the position of the lens barrel and absorbing the vibration of the lens barrel, the displacement amount and tilt measuring apparatus of the lens module. The method of claim 3, wherein The jig is the displacement amount and tilt measurement apparatus of the lens module, characterized in that for fixing the lens barrel to move up and down. The method of claim 3, wherein Displacement and tilt measuring device of the lens module, characterized in that the light is a laser beam. The method of claim 5, Displacement and tilt measuring device of the lens module, characterized in that the laser beam is a line scan type. delete A displacement amount and tilt measurement method of a lens module having a configuration of claim 3 and a tilt measuring device, Irradiating light to the lens barrel in a direction away from the center of the lens by a displacement sensor, and sensing the distance between the displacement sensor and the lens barrel to which the light is irradiated at at least two points; Measuring a tilt value using the difference of the sensed distances; And Measuring the displacement of the lens by the displacement sensor while moving the lens barrel up and down; Including The sensing step may further include rotating the lens barrel about an axis of the lens to sense the distance between the displacement sensor and the lens barrel at at least two points while the displacement sensor is fixed. How to measure displacement and tilt of lens module. The method of claim 8, Displacement and tilt measuring method of the lens module, characterized in that the light is a laser beam. 10. The method of claim 9, Displacement and tilt measurement method of the lens module, characterized in that the laser beam is a line scan type.

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