TWI617856B - Lens group correction method - Google Patents

Abstract

In the lens group correction method of the present invention, the light from the light source is mainly used through the lens, and is projected onto the light sensor to sense the projection pattern, and then based on the standard projection pattern and the detected projection pattern, Adjust the position of the lens in the lens carrier until the gap between the standard projection pattern and the sensed projection pattern is within a predetermined range, so that each lens has the same optical characteristics as the standard lens. The lens group is composed of a lens holder and a lens, and the lens holder has a coupling structure with the lens, so that the lens can be moved within the lens holder along the combination structure.

Description

Lens group correction method

The invention relates to a voice coil motor; in particular, to a lens group correction method.

In order to precisely control the head arm of the lens group or hard disk, a voice coil motor (VCM) is usually used to move the head arm of the lens group or hard disk. The mechanism of the voice coil motor is mainly to place the coil in a magnetic circuit containing a permanent magnet.

In the optical system, when the current passes through the coil, the magnetic field formed by the permanent magnet will generate an interactive propulsive force according to Fleming's left-hand rule, so that the holder rigidly connected to the permanent magnet is moved, and at the same time, it is fixed to the lens holder To achieve the purpose of optical zoom and focus.

However, in the process of mass production, tolerances will inevitably be caused, resulting in a difference in the optical performance and appearance of each lens group of the same model, which needs to be corrected according to the standard lens group. More specifically, if the initial positions of the lenses in the uncorrected lens group are inconsistent, in addition to affecting the overall height of the voice coil motor, it will also cause a difference in focal length between the voice coil motors.

In the conventional correction methods, the initial position of the lens in the lens holder is usually measured by comparing the height difference between the top of the lens holder and the top of the lens, and then the position of the lens is adjusted to be equivalent to that of a standard lens. degree. However, in addition to the trouble of this measurement method, it is also easy because the lens itself has tolerances on the top of the external mount, which results in unsatisfactory correction results.

For this reason, the main purpose of the present invention is to provide a lens group correction method, which mainly compares the standard The difference in diameter in the projection pattern between the lens and the lens to be adjusted, and the lens to be adjusted is adjusted upward or downward until the difference is acceptable.

Based on the above purpose, in the lens group correction method of the present invention, the light from the light source is first passed through the lens, and the light is aligned and projected onto the light sensor to sense the projection pattern, and then based on the standard projection pattern and the sensed Adjust the gap between the measured projection patterns, and adjust the position of the lens in the lens carrier until the gap between the standard projection pattern and the sensed projection pattern is within a predetermined range, so that each lens has a standard lens. Same optical characteristics. The lens group is composed of a lens holder and a lens, and the lens holder has a coupling structure with the lens, so that the lens can be moved within the lens holder along the combination structure. The advantages and spirit of this creation can be further understood through the following new detailed description and attached drawings.

30‧‧‧ base

60a, 60b‧‧‧light

70‧‧‧ lens mount

701, 702‧‧‧Abutment structure

705‧‧‧ opening

706‧‧‧female thread

80‧‧‧ lens

801, 802‧‧‧guide shaft

803‧‧‧adjusting claw

90‧‧‧ light source

100‧‧‧light sensor

101‧‧‧standard projection pattern

101a‧‧‧ diameter line

102‧‧‧ Projection pattern

102a‧‧‧diameter line

103‧‧‧center

Figures 1A ~ 1B are schematic diagrams of the voice coil motor of the present invention.

FIG. 2 is a schematic diagram of a lens group correction method of the present invention.

3A ~ 3B are another schematic diagram of the lens group correction method of the present invention.

Please refer to FIGS. 1A to 1B, which are schematic diagrams of the voice coil motor of the present invention. As shown in FIGS. 1A to 1B, the voice coil motor of the present invention includes a base 30, a set of guide shafts 801 and 802 fixed on the base 30, fixed circuit components (not shown; mainly composed of a coil), and a lens bearing base. 70 (including a magnetic sensor (not shown) and a lens 80 rigidly connected (as shown in FIG. 2)). In order to allow the lens carrier 70 to vertically move up and down along the guide shafts 801 and 802, the lens carrier 70 has a first abutment structure 701 and a second abutment structure 702 outside the first abutment structure. 701 and second abut The structure 702 is symmetrical in position setting. The opening 705 of the lens carrier 70 can be used to mount the lens 80 and has a coupling structure between the lens carrier 70 and the lens 80, so that the lens 80 can be slightly moved up and down in the lens carrier 70 along the coupling structure. For example, when the coupling structure is a male-female thread, the inner wall surface of the lens carrier 70 has a female thread 706, and the lens 80 has a corresponding male thread, so as long as the lens 80 is rotated along the male-female thread, the lens can be 80 let the quilt move up and down slightly.

Please refer to FIG. 2, which is a schematic diagram of the lens group correction method of the present invention. As shown in FIG. 2, in order to implement the lens group correction method of the present invention, a light source 90, an adjustment claw 803 additionally mounted on the lens 80, and a light sensor 100 (such as a CCD or CMOS) need to be prepared. Among them, as long as the fingers hold the adjusting claw 803, the lens 80 can be rotated along the male and female threads, and the lens 80 can be moved up and down slightly.

Before implementing the correction method, the light 60a of the light source 90 needs to be incident parallel to the lens 80, and a light sensor 100 is placed directly below the lens 80 to sense the projection pattern 102 projected by the light 60b after passing through the lens 80. (As in Figure 3A or 3B). Finally, the standard projection pattern 101 is used as a basis, the degree of deviation of the projected projection pattern 102 is compared, and the position of the lens 80 is adjusted, so that each lens 80 to be detected has the same optical performance.

Before the actual detection, a standard projection pattern needs to be provided, which means that a specific lens is first adjusted to meet the optical performance in accordance with the specifications by traditional means, and then the light sensor 100 is used with the architecture shown in Figure 2 Obtain the relative projection pattern and define it as the standard projection pattern 101. Below, the principle of adjustment will be explained in more detail.

Please refer to FIGS. 3A to 3B, which are another schematic diagram of the lens group correction method of the present invention. As shown in Figures 1A ~ 1B, in the lens group correction method of the present invention, it is mainly based on the standard projection The gap between the shadow pattern 101 and the sensed projection pattern 102, adjust the position of the lens 80 in the lens carrier 70 until the gap between the standard projection pattern 101 and the sensed projection pattern 102 is within a predetermined range .

Specifically, as shown in FIG. 3A, when the sensed projection pattern 102 is larger than the standard projection pattern 101, the lens 80 in the lens holder 102 is adjusted to move toward the position of the light sensor 100 (that is, move downward). ) Until the gap between the standard projection pattern 101 and the sensed projection pattern 102 is within a predetermined range. As shown in FIG. 3B, when the sensed projection pattern 102 is larger than the standard projection pattern 101, the lens 80 in the lens carrier 102 is adjusted to move toward the position of the light source 90 that provides the light 60a (that is, moves upward) until The gap between the standard projection pattern 101 and the sensed projection pattern 102 is within a predetermined range.

There are many ways to compare the size of the projection pattern 102 and the standard projection pattern 101, such as comparing the area. However, in order to simplify the comparison method, only the diameters of the projection pattern 102 and the standard projection pattern 101 can be compared, which means that only a single pass is compared. The center point 103 has diameter lines 101a and 102a. If the error caused by the insufficient resolution of the light sensor 100 is taken into account, the edges of the projection pattern 102 and the standard projection pattern 101 are not smooth enough, and it may not be able to present a perfect perfect circle (each diameter line passing through the center point 103) The lengths of 101a and 102a are the same), and several diameter lines 101a and 102a can be compared at the same time. That is, when the lengths of the plurality of diameter lines 101a and 102a are the same, the length is regarded as the diameter length of the projection pattern 102 and the standard projection pattern 101. If a few of the diameter lines 101a and 102a have a difference in length, the deviation is eliminated, and the larger number is used as the diameter length of the projection pattern 102 and the standard projection pattern 101.

For example, as shown in FIGS. 1A to 1B, the standard projection pattern 101 and the sensed projection pattern 102 are each defined with a center point 103 and diameter lines 101 a and 102 a passing through the center point 103. Wherein, both ends of the diameter lines 101a and 102a touch both edges of the standard projection pattern 101 and the sensed projection pattern 102. Therefore, the lengths of the diameter lines 101a and 102a can be calculated from the coordinates of the two ends. Therefore, in order for each lens 80 to have the same optical performance, the gap between the diameter line 101a of the standard projection pattern 101 and the diameter line 102a of the sensed projection pattern 102 must be within a predetermined range. Among them, the predetermined range is -0.02mm ~ 0.02mm, and the most preferable range is -0.01mm ~ 0.01mm. If the difference is not within the predetermined range, the position of the lens 80 in the lens bearing base 70 needs to be adjusted.

Specifically, as shown in FIG. 3A, when the sensed diameter line 102 a of the projection pattern 102 is larger than the diameter line 101 a of the standard projection pattern 101, the lens 80 in the lens carrier 102 is adjusted to face the light. The position of the detector 100 is moved (that is, moved downward) until the gap between the diameter line 101a of the standard projection pattern 101 and the diameter line 102a of the sensed projection pattern 102 is within a predetermined range. As shown in FIG. 3B, when the sensed diameter line 102a of the projection pattern 102 is larger than the diameter line 101a of the standard projection pattern 101, the lens 80 in the lens mount 102 is adjusted to move toward the position of the light source 90 providing the light 60a. (Ie, moving upward) until the gap between the diameter line 101a of the standard projection pattern 101 and the sensed diameter line 102a of the projection pattern 102 is within a predetermined range.

With the above detailed description of the preferred embodiments, it is hoped that the characteristics and spirit of the creation can be described more clearly, rather than limiting the scope of the creation with the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equitable arrangements within the scope of the patents that this creation intends to apply for.

60a, 60b‧‧‧light

70‧‧‧ lens mount

80‧‧‧ lens

803‧‧‧adjusting claw

90‧‧‧ light source

100‧‧‧light sensor

Claims (10)

A method for correcting a lens group. The lens group is composed of a lens holder and a lens. The lens holder and the lens have a combination structure so that the lens can be moved along the combination structure in the lens holder. The method includes: using a light sensor to sense a projection pattern projected by light passing through the lens; and adjusting the lens bearing base based on a gap between a standard projection pattern and the sensed projection pattern. Until the gap between the standard projection pattern and the sensed projection pattern is within a predetermined range. The method for correcting a lens group according to item 1 of the scope of the patent application, wherein the coupling structure between the lens carrier and the lens is a male-female thread. The lens group correction method according to item 1 of the scope of patent application, wherein the predetermined range is -0.02mm ~ 0.02mm. The lens group correction method according to item 3 of the scope of patent application, wherein the predetermined range is preferably -0.01mm ~ 0.01mm. The lens group correction method described in item 1 of the scope of patent application, wherein the standard projection pattern and the sensed projection pattern are both determined There is a center point and a diameter line passing through the center point. Both ends of the diameter line touch the two edges of the standard projection pattern and the sensed projection pattern. The diameter line of the standard projection pattern and A gap between the sensed diameter lines of the projection pattern is within the predetermined range. The lens group correction method according to item 5 of the scope of the patent application, wherein a gap between the diameter line of the standard projection pattern and a plurality of diameter lines of the projection pattern sensed is within the predetermined range. The lens group correction method according to item 1 of the scope of the patent application, wherein when the sensed projection pattern is larger than the standard projection pattern, the lens in the lens carrier is adjusted to move toward the position of the light sensor until A gap between the standard projection pattern and the sensed projection pattern is within the predetermined range. According to the lens group correction method described in claim 5, wherein when the diameter line of the projection pattern sensed is larger than the diameter line of the standard projection pattern, the lens in the lens carrier is adjusted to face the light. The position of the sensor is moved until the gap between the standard projection pattern and the sensed projection pattern is within the predetermined range. The lens group correction method according to item 1 of the scope of patent application, wherein when the sensed projection pattern is smaller than the standard projection pattern, the lens in the lens carrier is adjusted to move toward a position of a light source providing the light, Until the gap between the standard projection pattern and the sensed projection pattern is within the predetermined range. According to the lens group correction method described in claim 5, wherein when the diameter line of the projection pattern sensed is smaller than the diameter line of the standard projection pattern, the lens in the lens carrier is adjusted to provide the The position of one of the light sources moves until the gap between the standard projection pattern and the sensed projection pattern is within the predetermined range.