TWI407078B - Micro - lens array surface profile detection system and its detection method - Google Patents

Abstract

The present invention provides a micro-lens array surface profile detection system and detection method, the system includes fine-tuning type placement positioning unit, optical image grabbing module, optical interference module, central control unit and image processing operating module; wherein the image processing module applies plural image processing operations to image data; characterized in that the image processing operating module, through image segmentation and area recognition, identifies the center position of each ring, and the micro-lens array image substrate is determined according to graphical segmentation and area recognition methods to automatically identify the background of the micro-lens array interference image. Based on the ratio of the actual center ring area and the ideal center ring area, the phase angle variation of the center ring of said interference fringes is determined. Based on the ratio of actual brightness variation of the first segment ring stripe and the ideal brightness variation of the first segment ring stripe, phase angle variation in the ring interference fringe at the outermost substrate is determined. Area ratio method and brightness ratio method are freely interchangeable for choosing the method with higher precision. Maximum and minimum of every segment brightness curve are picked to correspond respectively to the brightness change in the segment phase angle from 0 to 180 degrees, and then the corresponding micro-lens surface height differences between pixels on the segment are found. The present invention can accurately find the micro-lens interference fringe, and accurately determine the phase angle of innermost and outermost rings of the interference fringe, thereby improving significantly accuracy and quality of micro-lens array surface profile detection.

Description

Microlens array surface contour detecting system and detecting method thereof

The invention relates to a detection system and a detection method, in particular to an innovative design of a detection system and method for the surface profile of a microlens array.

According to the traditional method of detecting the surface contour of the non-contact measuring microlens array, it is divided into interference and non-interference. If it is measured by interference, optical profiler method, computer holographic interferometry, shearing interferometry, etc.; non-interference measurement method, including transmission knife method, line measurement method, and Ronchi law.

The conventional technique related to the present case is the optical profiler method, which is based on the white light interference theory, and directly records the contour surface thereof by a direct interference, and the composition mechanism includes a microscopic image capturing system. The phase shifting system and the interferometer system are composed, and the measuring principle is to measure the phase difference between the wavefront of the device to be tested and the reference wavefront by the interferometer, and the wavefront of the device to be tested is reflected by the contour of the surface to be tested. The reference wavefront is generated by the reference surface reflection of the reference plate; the interference fringes are generated due to the phase difference between the reference wavefronts, and the stripe can reflect the difference between the surface height and the surface contour of the CCD. The profiler's optical path uses a phase-shifting technique to determine the phase difference and phase reconstruction techniques to reconstruct a three-dimensional surface contour. This instrument is widely used in MEMS structures, aspherical microarray structures, film thickness measurement, etc.

However, the above optical profilometry method can search for the interference fringes of all the lenses, but interferes with the innermost and outermost circular rings of the stripe. The conventional method still cannot judge the phase angle, and the cover phase does not have the phase angle of the two parts. It must be a state in which the 0 degree changes to 180 degrees. In addition, the remaining ring phase angles are changed from 0 degrees to 180 degrees, so the change from light to dark is a complete 180 degree change. Therefore, the conventional microlens array surface contour detection system still has the defects and shortcomings of the large judgment error phenomenon, and it is necessary to further improve the evolution.

Therefore, in view of the problems existing in the above-mentioned conventional microlens array surface contour detection system and method, how to develop an innovative design that can be more ideal and practical, and the relevant industry and interested people should further consider the breakthrough goal and direction.

In view of this, the inventor has been engaged in the manufacturing development and design experience of related products for many years. After detailed design and careful evaluation, the inventor has finally obtained the practical invention.

The main object of the present invention is to provide a microlens array surface contour detecting system and a detecting method thereof, and the problem to be solved is to develop a more ideal and practical microlens array detecting system and its detection. The method aims to solve the problem; the technical feature of the invention solves the problem, and the system includes a fine-tunable positioning part, an optical image capturing module, an optical interference module, a central control part, and an image processing operation mode. The image processing operation module is disposed in the central control unit to remove noise noise, search for image feature points, and generate interference fringes and contours with a central ring and a plurality of inner and outer rings. Image processing operation such as analysis and tabulation; the core design of the present invention mainly lies in that the image processing operation module finds the center position of each ring through the method of pattern segmentation and area recognition, and the judgment of the image base of the microlens array is Automatically find out the background of the entire microlens array interference image according to the method of pattern segmentation and area recognition. The ratio of the central ring area to the ideal central ring area is used to determine the amount of change in the center angle of the center of the interference fringe, and the amount of change in the brightness value of the annular stripe of the first section and the circle of the ideal first section The ratio of the change in the brightness value of the ring stripe is used to determine the amount of change in the phase angle of the ring stripe at the outermost base of the interference fringe, and the area ratio method and the brightness ratio method are all freely switchable, and the method of selecting a higher precision is used. Then find the maximum and minimum values of the brightness curve of each segment, respectively corresponding to the brightness change of the segment phase angle from 0 degrees to 180 degrees, and then determine the corresponding microlens surface height between the points in the segment. With this innovative and unique design, the present invention and the method disclosed in the present invention can accurately search for the interference fringes of the lens and accurately determine the innermost and outermost annular phase angles of the interference fringes. Achieve the advantages and progress of greatly improving the accuracy and quality of the surface contour detection of the microlens array.

Please refer to Figures 1 and 2 for a preferred embodiment of the present invention, but the embodiments are for illustrative purposes only and are not limited by the structure; the detection system is used to detect micro For the surface profile of a micro-lens Array, the detection system A comprises the following components: a fine-tunable placement positioning portion 10 having a placement surface 11 for positioning the microlens array 05. And the fine-adjustable positioning positioning portion 10 is capable of performing a micro-displacement adjustment of at least two horizontal axes of the X and Y axes; the fine-adjustable positioning positioning portion 10 can be an XY-axis numerical control platform (XY-Table) The XY-axis numerical control platform is used to perform precise displacement of the microlens array 05, and the whole microlens array 05 can be completely scanned, and the microlens array 05 can be positioned; an optical imaging module 20 The optical image capturing module 20 includes an image capturing device 21 (which can be a CCD camera) and a microscope group 22, which is disposed at an interval above the placement table 11 of the fine-tunable positioning portion 10. The microscope group 22 is opposite to the image capturing device 21 State; an optical interference module 30 is applied to a Fizeau interferometer architecture, including a laser emitter 31, an optical fiber 32, a vibrator and polarizer 33, a half reflector 34, and a reference plate 35. The vibrator and the polarizer 33 are disposed in front of the emitting end of the laser emitter 31. The optical fiber 32 is disposed outside the vibrator and the polarizer 33 to guide the laser light W. The semi-reflecting plate 34 is disposed. Between the image capturing device 21 of the optical imaging module 20 and the microscope group 22, the laser light W derived from the optical fiber 32 is reflected and guided to the microscope group 22, and the reference plate 35 is placed in the microscope group 22 and The micro-adjustable placement portion 10 is disposed between the placement surfaces 11 to reflect light from the portion of the second surface of the reference plate 35 by using the laser light W as a reference wave surface for detecting the surface contour of the microlens array; a central control portion 40, can be a computer, and the micro-adjustable positioning positioning portion 10, the optical imaging module 20, the optical interference module 30 are electrically connected, thereby achieving the function of integrated control actuation; an image processing operation mode The group 50 is disposed in the central control unit 40, The image data captured by the image capturing device 21 includes removing noise noise, finding image feature points, generating interference fringes having a center ring and a plurality of inner and outer rings (similar to Newton's rings), and contour analysis. Image processing and logic operation operations such as tabulation; and wherein the image processing operation module 50 selects a phase angle change of the center of the interference fringe according to a ratio of an actual central ring area to an ideal central ring area. And determining the ring stripe at the outermost base of the interference fringe according to the ratio of the change amount of the brightness value of the ring stripe of the first section to the change amount of the brightness value of the ring stripe of the ideal first section The amount of phase angle change.

In connection with the above, the detection method of the detection system A includes the following steps:

(A), the micro-adjustable positioning positioning portion 10, the image capturing device 21 of the optical imaging module 20 and the laser emitter 31 of the optical interference module 30;

(B) performing a connection setting between the image capturing device and the fine-tunable positioning portion through a threaded manner;

(C), setting the moving distance of the fine-adjustable positioning positioning portion 10, for example, if the size of the microlens array of the object to be tested is an array of 86 mm × 86 mm, the amount of each shift can be set to 0.1 mm;

(D) performing displacement in the X-axis direction by using the moving distance set in the step (C);

(E), when the step (D) is moved by a set distance in the X-axis direction, the image capturing device performs the image capturing operation;

(F) acquiring the interference fringe image of the microlens array 05 by the image capturing device 20, and removing the noise and the noise by the image processing operation module to obtain an image pattern that is easy to analyze;

(G), the image processing operation module 50 searches for image feature points by image processing, and then performs lens surface contour analysis according to the image feature points found, and draws the result of the lens surface contour analysis into The image processing operation module 50 searches for all interference fringes to calculate the entire lens radius and contour, and can determine the inner and outermost annular stripe phase angle variation of the interference fringe, wherein the image is judged. The change of the phase angle of the ring stripe of the center ring is determined according to the ratio of the actual central ring area to the ideal central ring area; and the change of the phase angle of the ring stripe at the outermost base is determined according to the actual number. The ratio of the change in the luminance value of the ring strip of the 1 segment to the change in the luminance value of the ring stripe of the ideal first segment is used to determine the amount of phase angle change (this portion will be described later in detail);

(H), after the fine-adjustable placement positioning unit 10 performs the X-axis direction movement setting number (for example, 100 times), the fine-adjustable positioning positioning unit 10 is displaced in the Y-axis direction by a set distance (0.1 mm). , in order to transform into the image path of the next column, and then let the fine-tunable positioning portion 10 continue to shift in the X-axis direction (for example, 100 times);

(I), repeating the foregoing steps (E) to (H) until the intact bulk microlens array 05 is detected.

Wherein, the detecting method is based on the principle of the Fizeau interferometer, and the annular interference fringes (ie, Newton's rings) are formed by the mutual interference principle of the reflected light generated by the optical interference module, and the number of turns of the annular interference fringes is utilized Obtaining a height of each of the curved contours of the lens; and performing processing on the feature points of the circular interference fringes having different brightness levels to obtain a surface contour map of each of the lenses; and generating the optical image according to the microlens array The plurality of annular interference fringes can obtain the center point coordinate positions of the annular interference fringes simultaneously by the arithmetic processing of the image processing arithmetic module.

Further details of the detection of the present invention are further described below:

Image processing: (please refer to the figure shown in Figure 2)

The image taken from the image capture device will have several microlens arrays (as shown in Figure 3). This image processing is to divide each microlens array so that it can be individually processed for a single microlens.

Image processing:

In the pre-image processing, low-pass filtering and on-operation can be used to eliminate the noise in the image through these two processes; then the binarization operation is performed on the image, and the image is converted into black and white at a threshold. Color, at this time, the circular interference fringes of each microlens can be clearly seen.

Find image feature points:

1. First, image segmentation is performed to determine the most pixels as the background, and the image segmentation process is used to facilitate the subsequent steps to find the center of a single microlens and its center circle;

2. Check whether each image that is segmented is round, starting from the center of each image, extending at 0°, -180°, 90°, -90°, and analyzing whether the four sides of the radius are the same, if the same Determined to be round;

3. The image determined to be a round shape is analyzed for its area size, and the area is the smallest, and it is determined to be the center circle;

4. Find the center circle and find the center of the center circle.

Object segmentation:

First, all closed pixels are divided into several objects, and each object is labeled; plus the background is also an object, which can be divided into n objects. Among the n objects, the area of each object (the number of pixels) can be known, and the object with the largest area will be defined as the background, that is, the portion of the base of the microlens array.

Center Search:

The center search is to find the center of the divided object, and add the coordinates of the horizontal direction (x-axis) and the vertical direction (y-axis) of the white pixel in the object individually, and calculate the total pixel of the object. The reference formula is as follows:

Round judgment:

To confirm that the segmented objects are all circular, if the image contains incomplete microlenses (the interference ring is curved or semi-circular (as shown in Figure 4)), the object will be listed. It is non-circular. Then, as shown in Figure 5, after the center search for the object center ( x _{c ,} y _c ), it extends at 0°, -180°, 90°, -90°, and encounters the first black pixel. Stop, the extension in four directions gives the right limit p _R , the left limit p _L , the upper limit p _T , and the lower limit p _B . Calculate the distance between the four limit points and the center to obtain the four radius distances of the object. The radius distance from the center to the right limit point D _CR , the radius distance from the center to the left limit point D _CL , the radius distance from the center to the upper limit point D _CT ; the radius distance from the center to the lower limit point D _CB , where:

D _CR = P _R - X _c

D _CL = X _c - P _L

D _CT = Y _c - P _T

D _CB = P _B - Y _c

The radius of the perfect circle is the same, so the maximum value and the minimum value of the four radius distances are subtracted. If the distance is greater than a certain tolerance T (several pixels), the closed area is judged to be non-circular. If the distance is less than a set tolerance value T (several pixels), the closed area is judged to be a perfect circle.

Microlens center circle search:

When the background and non-circular have been excluded, then the center circle of the microlens can be searched. In the foregoing segmentation method, a microlens can be divided into several objects and each object is concentric. If the center of the object is found to extend to the background, the object corresponding to the microlens can be known, and then the corresponding object is The object area is the smallest, and the object closest to the center of the circle is the center circle of the microlens.

Microlens positioning:

After obtaining the center circle of the microlens, the center of the microlens is obtained. By extending the center of the circle to the background of the interference image, the position of each microlens and the radius and contour of the entire lens can be obtained. The method is to extend from the center of the circle to 0°, -180°, 90°, and -90°, and the extension in the four directions is the right limit x _R , the left limit x _L , the upper limit y _T , and the lower limit y _B . Through these four extreme coordinates, you can use ( x _R , y _T ), ( x _R , y _B ), ( x _L , y _B ), ( x _L , y _T ) to frame a single microlens (such as Figure 10) is positioned, and a single microlens structure is shown in Figure 9.

Analysis of Fizeau interferometer and lens array:

The principle of the Fizeau interferometer can be explained by light interference. The distance between the partial mirror of the Fizeau interferometer and the air wedge of the object reflection surface is d, because the light reflected by the object reflection surface is reflected by the action surface of the partial mirror. The light traverses the optical path difference of 2d, so the phase difference required for the two optical interferences is formed, and interference fringes are formed. The interference fringes can be directly seen by the naked eye, and can also be obtained by CCD. The air wedge can be calculated from the number of black interference fringes. The distance of the interval, the formula of the black interference fringe is as follows: 2d = (n + 1/2) λ

n: the number of stripes

d: air wedge spacing

λ: wavelength of light between air

As shown in Fig. 6, the Fizeau interferometer is formed by a spherical surface and a light reflected by a plane to form an annular stripe. These interference fringes (as shown in Fig. 7) are similar to Newton's Rings. By _{(x R, y T),} (x R, y B), (x L, y B), (x L, y T) after a single microlens block, the grayscale values of the image reduction, together with the ( x _R , y _T ), ( x _R , y _B ), ( x _L , y _B ), ( x _L , y _T ) outside the box to another microlens box, along the single micro the direction of the center of the lens, which is obtained gray value change curve, see Figure 8, which is left to right, sequentially numbered first sector, second sector, ... of the luminance profile. Find the maximum value of the i section of the brightness curve and the minimal value of T _{i D i, g (x, y} ) is the luminance of the i-th curve segment pels (x, y) of the luminance value; brightness curve of the i-th segment i -1 and the maximum value of the maximum value of luminance with a little section T _{i -1} = T _i; minimum luminance profile of the i-th segment and the second segment i + 1'd luminance point with the minimum value D _i = D _{i +1} ; in each segment, the interference fringe brightness value I is proportional to the inner product of the first reflected light intensity E ₁ and the second reflected light intensity E ₂ : Among them, the relationship between I and E ₁ and E ₂ is as follows:

I is the interference fringe brightness of the first light and the second light

E ₁ is the first reflected light intensity

E ₂ is the intensity of the second reflected light. It is known that the brightness of the interference fringes in the segment exhibits a distribution of the cosine curve.

The phase angle of the interference fringe changes from 0 degrees to 360 degrees, showing a change from light to dark to bright, representing the undulation of the surface of the microlens as λ/2, and the innermost and outermost ring of the interference fringe. The method is that there is no way to judge the phase angle. That is to say, the phase angles of the two parts do not necessarily change from 0 degrees to 180 degrees. In addition, whether it is bright or dark, it is a ring, and the rest is left. The phase angle of the ring changes from 0 degrees to 180 degrees. The change from light to dark is a complete 180 degree change. The phase angle changes from 0 degrees to 180 degrees, which means that the surface roughness of the microlens is λ/4. So we develop an innovative way to judge The change in the phase angle of the inner ring and the change in the phase angle of the ring strip at the outermost base are probably not a complete change. We can use the innovative method we developed to judge the amount of change.

Judging the change of the phase angle of the ring stripe of the center ring ( α ), please refer to the figure shown in Figure 11: The phase angle variation of the center ring can be judged according to the ratio of the actual center ring area to the ideal center ring area ( α ). Assuming that the central ring is the nth segment, the ideal central ring area can be extrapolated from the area of the second ring of the center ( n-1 segment) by the coefficient: Where A is the center ring area

A' is the area of the ring of the n-1 section

τ ₁ is the area scale factor

Judging the amount of change in the phase angle of the ring stripe ( β ) at the outermost base (first segment), please refer to Fig. 12: The amount of change in the brightness value of the ring stripe according to the actual first section and the ideal first The phase angle change amount ( β ) is determined by the ratio of the change in the luminance value of the ring stripe of the segment. The amount of change in the brightness value of the ideal first-segment ring may be obtained by multiplying the change in the luminance value of the ring-stripes of the two segments by the coefficient, or by the difference in the variation of the luminance values of the second and third segments: Where Δg is the change in the luminance value of the ring stripe of the first section

Δg' is the amount of change in the luminance value of the ring stripe of the second section

τ ₂ is the ratio of the change in the brightness value

Let Δ _i be the change in brightness of the phase angle of the i-th segment from 0 to 180 degrees, when i =1,

When i = n ,

When 1 < i < n , Δ _i is the difference between the maximum value and the minimum value of the luminance curve, Δ _i =| T _i - D _i |

Let A _i be the luminance value when the phase angle of the i-th segment is 90 degrees.

When i =1,

When 1< i = n ,

The difference δ θ ( x , y ) between the phase angles of the luminance curve points (x, y) and (x+1, y) is as follows:

Let the segment where the center circle ( x _c , y _c ) is the nth segment, then the points from the second segment to the (n-1) segment (x, y) and (x+1, y) The value of the microlens surface height difference δ d(x) corresponding to each other can be obtained by the following formula:

The variation of the phase angle of the interference fringe is as shown in FIG. 13; the micro-corresponding to each adjacent pixel of the segment where the central segment ( x _c , y _c ) of the microlens is accumulated by the first segment is accumulated. Lens surface height difference, can calculate Lens Sag (△ d )

Please refer to Figure 14 for the calculation of the radius of curvature of the interference fringe. If B(x ₂ , y ₂ ) is the highest point of the lens, take the two points A(x ₁ , y ₁ ) and C. (x ₁ , y ₁ ) ( A and C can also be the two endpoints of the surface). The slopes m ₁ and m _{2 of} the line segment AB and the line segment BC are respectively

The vertical line L ₁ and L ₂ are respectively made for the line segment AB and the line segment BC , and the slopes thereof are respectively

Then the equations of L ₁ and L ₂ are respectively

L ₁ : y = m ₁ ' x + c ₁

L ₂ : y = m ₂ ' x + c ₂

Using the simultaneous equations of L ₁ and L ₂ , the intersection point D(x, y) of the two-line equation can be found as

Calculate the distance between the two points B and P to find the radius of curvature r of the interference fringe

In the quantitative analysis of interference fringes, it is not necessary to find the contact point or the reference point deliberately. If the optical plate intersects the measured surface of the workpiece at a slight angle, the fringes generated on it represent the Fizeau interferometer and the The height of the air wedge at the opposite point of the face. We can arbitrarily make a point on the surface of the workpiece as the reference point, and then push the air wedge height of the whole surface of the workpiece forward and backward (please refer to the figure shown in Figure 15). Finally, the tilting height of the optical plate is buckled off, and the workpiece is obtained. The surface of the measured surface is undulating.

At this time, R ² = r ² +( R - d ) ² = r ² + R ² -2 Rd + d ²

That is: 0= r ² -2 Rd + d ²

d is small, you can ignore its quadratic term, you can get r ² -2 Rd =0

which is

Assume that the gap of the m-th order dark surface is d _m

d _m = mλ/2

Substituting

After simplification, the position r _m of the dark line in the interference fringe of the mth circle and the radius R of the spherical microlens, and the relationship of the wavelength λ of the interference light are as follows:

Example:

The microlens array used in this embodiment has a radius of 110 μm, a radius of curvature of 1.561 mm, and an array size of 10 mm × 10 mm × 1.2 mm.

The invention adopts a Fizeau interferometer as a hardware structure to capture an image, and the light source thereof can be a strontium laser with a wavelength of 632 nm, and the obtained image is as shown in FIG. 4, thereby analyzing the curved contour of the lens. The height is 0.9 to 1.1 μm, and it is found by the mathematical proof that the height of the curved profile of the lens is 1.0 μm. The invention is a detection system for measuring the microlens array in a non-contact manner, the image of the microlens array is taken out by the image capturing device, and the radius and the center point position of the lens are obtained through image processing, and then the Fisso The interference principle of the interferometer obtains the interferogram of the lens. After the mathematical analysis and calculation, the shape information of the microarray is obtained. The error of the lens diameter is less than 1%, and the error of the bending height is less than 1%.

Advantages of the invention:

The "microlens array surface contour detecting system and the detecting method thereof" mainly comprises the micro-adjustable positioning positioning portion, the optical image capturing module, the optical interference module, the central control portion and the image processing computing module. Design; the optical interference module uses the Fizeau interferometer architecture and cooperates with the image processing computing module, and the central region selects the phase angle variation of the center of the interference fringe according to the ratio of the actual central ring area to the ideal central ring area, and The outermost region is selected according to the ratio of the change amount of the actual ring stripe brightness value to the change amount of the ideal ring stripe brightness value, and the unique design of the ring stripe phase angle variation at the outermost base of the interference fringe is determined. Both methods can be freely selected. In order to improve the judgment accuracy; the invention can accurately search for the interference fringe of the lens, and accurately determine the innermost and outermost annular phase angle of the interference fringe, thereby achieving the advantages of greatly improving the precision and quality of the surface contour detection of the microlens array and Progressive.

The above embodiments are intended to be illustrative of the present invention, and are not to be construed as limiting the scope of the invention. The principles are changed and modified to achieve an equivalent purpose, and such changes and modifications are to be included in the scope defined by the scope of the patent application as described later.

05. . . Microlens array

A. . . Detection Systems

10. . . Fine-adjustable positioning position

11. . . Place the countertop

20. . . Optical imaging module

twenty one. . . Image capture device

twenty two. . . Microscope group

30. . . Optical interference module

31. . . Laser transmitter

32. . . optical fiber

33. . . Vibrator and polarizer

34. . . Semi-reflecting plate

35. . . Reference board

40. . . Central control department

50. . . Image processing computing module

Figure 1: Schematic diagram of the architecture of the detection system of the present invention.

Figure 2 is a block diagram showing the flow of the local detection method of the detection system of the present invention.

Figure 3: Schematic representation of the microlens array of the present invention.

Fig. 4 is a view showing the judgment of the divided object of the present invention (arc or semicircle is judged to be non-circular).

Figure 5: Schematic diagram of the four radius distances of the articles of the invention.

Figure 6: Schematic diagram of the Fizeau interferometer of the present invention.

Figure 7 is a schematic view of the annular interference fringes of the present invention.

Figure 8 is a schematic view showing the gray scale value change curve of the present invention.

Figure 9 is a schematic view showing the structure of a single microlens of the present invention.

Figure 10 is a schematic view of a single microlens image of the present invention.

Figure 11 is a schematic view showing the variation of the phase angle of the ring stripe of the center circle of the present invention.

Fig. 12 is a schematic view showing the curve of the change in the phase angle of the annular stripe at the outermost base of the present invention.

Figure 13 is a schematic view showing the change of the phase angle of the interference fringe of the present invention.

Figure 14: Schematic diagram of the calculation of the radius of curvature of the present invention.

Figure 15 is a schematic view showing the overall air wedge height of the working surface of the Fizeau interferometer of the present invention.

05. . . Microlens array

A. . . Detection Systems

10. . . Fine-adjustable positioning position

11. . . Place the countertop

20. . . Optical imaging module

twenty one. . . Image capture device

twenty two. . . Microscope group

30. . . Optical interference module

31. . . Laser transmitter

32. . . optical fiber

33. . . Vibrator and polarizer

34. . . Semi-reflecting plate

35. . . Reference board

40. . . Central control department

50. . . Image processing computing module

Claims (9)

A microlens array surface contour detecting system for detecting a surface contour of a microlens array, the detecting system comprising a finely adjustable positioning portion, an optical image capturing module, an optical interference module, and a central control portion The image processing computing module is configured by the central processing unit, wherein the image data captured by the image capturing device includes removing noise and finding image feature points. An image processing operation is performed to generate an interference fringe having a center ring and a plurality of inner and outer rings, and contour analysis and tabulation; and wherein the image processing operation module is capable of finding each through a method of pattern segmentation and area recognition. The center position of the ring, and the judgment of the image base of the microlens array is based on the method of pattern segmentation and area recognition to automatically find the background of the entire microlens array interference image (ie, the base portion of the microlens array). According to the area ratio method and the brightness ratio method to determine the phase angle change of the first section and the central section, the area ratio method is based on the actual ring The ratio of the product to the ideal ring area is used to determine the amount of change in the phase angle of the interference fringe ring. The law of brightness ratio is based on the ratio of the change in the brightness value of the actual ring stripe to the change in the brightness value of the ideal ring stripe. Both the method and the brightness ratio method can be switched freely, and the method with higher precision is used to determine the change of the phase angle of the ring stripe at the outermost base of the interference fringe, and then the maximum value of the brightness curve of each section is found. And the minimum value, corresponding to the change of the phase angle of the segment from 0 degrees to 180 degrees, respectively, and then the corresponding micro-lens surface height difference between the points in the segment is obtained. The microlens array surface contour detecting system of claim 1, wherein the fine-adjustable positioning portion has a placement surface for positioning the microlens array, and the fine-tunable The positioning positioning portion is capable of performing a micro-displacement adjustment of at least two horizontal axes of the X and Y axes; the optical image capturing module is disposed at an interval above the fine-adjustable positioning positioning portion, and includes an image capturing device and a microscope The microscope assembly is opposite to the image capturing device; the optical interference module is configured by using a Fizeau interferometer, including a laser emitter, an optical fiber, a vibrator and a polarizer, and a half reflector. a reference plate is configured, wherein the vibrator and the polarizer are disposed in front of the emitting end of the laser emitter, and the optical fiber is disposed outside the vibrator and the polarizer to guide the laser light, and the semi-reflective plate is disposed on the optical Between the image capturing device of the image capturing module and the microscope group, the laser light derived from the optical fiber is reflected and guided to the microscope group, and the reference plate is placed in the microscope group and the fine-tunable positioning and positioning portion. Between the mounting surfaces, the laser light is diffused into two or more light beams to serve as a light source for detecting the surface contour of the microlens array; the central control portion and the fine-adjustable positioning portion and the optical image capturing module are disposed. The optical interference module is electrically connected to achieve the function of integrated control actuation. The microlens array surface contour detecting system according to claim 1, wherein the fine-adjustable positioning portion is an XY-axis numerical control platform (XY-Table), and the XY-axis numerical control platform is used to perform the The precise displacement of the microlens array enables complete scanning of the entire microlens array and the ability to position the microlens array. The microlens array surface profile detecting system according to claim 1, wherein the central control unit is a computer. The microlens array surface contour detecting system according to claim 1, wherein the image capturing device is a high magnification CCD camera. A method for detecting a surface contour of a microlens array according to the detection method of the detection system according to claim 1, wherein the detection method comprises: (A) opening the fine-adjustable positioning portion and the optical image capturing module The image capturing device and the laser emitter of the optical interference module; (B), through a threaded connection between the image capturing device and the fine-tunable positioning positioning portion; (C), setting the The movement distance of the positioning portion can be finely adjusted; (D), the movement distance set by the step (C) is used to perform the X-axis direction displacement; (E), when the step (D) is moved by a set distance every X-axis direction The image capturing device performs the image capturing operation; (F), the image capturing device obtains the interference fringe image of the microlens array, and the image processing operation module removes the noise and the noise by the image processing method. Obtaining an easy-to-analyze image (G), by using the image processing computing module to find image feature points by image processing, separating all the ring patterns, confirming whether the segmented objects are circular, and thereby finding the center circle, and then according to the Finding image feature points, generating interference fringes with a central ring and a plurality of inner and outer rings, and performing lens surface contour analysis, and plotting the result of the lens surface profile analysis; and wherein: the image processing operation The module searches for all the interference fringes to calculate the radius and contour of the entire lens, and can determine the change of the phase angle of the innermost and outermost ring stripe of the interference fringe, wherein the ring stripe phase angle of the center ring is determined. The amount of change is judged according to the ratio of the actual central ring area to the ideal central ring area; and the change of the phase angle of the ring stripe at the outermost base is determined according to the brightness value of the ring stripe of the actual first section. The amount of change in phase angle is determined by the ratio of the amount of change to the amount of change in the brightness value of the ring stripe of the ideal first segment; (H), when the fine-tunable positioning portion is placed on the X-axis side After moving the set number of times, the fine-adjustable positioning positioning portion is displaced by a set distance in the Y-axis direction to be converted into the image capturing path of the next column, and then the fine-tunable positioning portion is further placed in the X-axis direction. Displacement; (I), repeat steps (E) through (H) until the intact bulk microlens array is detected. The method for detecting a surface contour of a microlens array according to claim 6, wherein the detecting method is based on the principle of a Fizeau interferometer, and the interference interference light generated by the optical interference module is used to form a ring interference fringe. Using the number of turns of the annular interference fringe to obtain the height of each of the curved contours of the lens; and performing processing on the feature points of the circular interference fringes with different radii of brightness to obtain the surface contour map of each lens; According to the complex annular interference fringes generated on the optical image of the microlens array, the center point coordinates of the annular interference fringes can be obtained simultaneously by the arithmetic processing of the image processing arithmetic module. The microlens array surface profile detecting method according to claim 6, wherein the ideal central ring area is calculated by multiplying the area of the second ring of the center periphery by a coefficient, or by the center periphery The area of the second and third ring is different. The method for detecting a surface contour of a microlens array according to claim 6, wherein the amount of change in the brightness value of the ideal first segment ring is calculated by multiplying the change in the luminance value of the ring segment of the two segments by a coefficient. However, it is obtained by the difference in the amount of change in the luminance values of the second and third sections.