KR20160125795A - Method and device for detecting an error for a refractive index of microlens - Google Patents

Abstract

According to an embodiment of the present invention, a method and a device to detect an error of a refractive index of a micro lens are capable of obtaining true information, completely excluding fake information and DC information, without a loss of three-dimensional shape information of an object by suggesting a phase transition technique using an optical modulator based on an inline single optical axis interferometer, thereby calculating an error of a refractive index of a micro lens, included in the inline single optical axis interferometer, by using the true information. Based on the error of the refractive index, the present invention is capable of determining whether the micro lens is defective or not. The technology is able to be used to determine a defect of the micro lens included in a camera which is normally supplied to a smart terminal.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and an apparatus for detecting a refractive index error of a microlens,

The present invention relates to a method and a device for detecting a refractive index error of a microlens, and a method and a device for detecting a refractive index error of a microlens for detecting the presence or absence of a defect in the microlens.

A photo is recorded by focusing an image on a film with a camera lens using light with low coherence such as natural light or an interior light, whereas a hologram is recorded on a film using an optical principle of interference. Therefore, in order to generate the hologram, highly coherent light such as a laser is used. Here, a photographic film on which an image of an object is recorded in the form of an interference fringe is referred to as a hologram, and a technique of restoring a stereoscopic image by recording a hologram is referred to as holography. Information of an object contained in an interference fringe recorded in a hologram can be reproduced as a stereoscopic image on an actual space using an optical principle called diffraction.

In this stereoscopic image reproduction, it is important to remove the noise included in the hologram image (i.e., DC (Direct Current) information and false image information) to obtain real image information. The conventional off-axis digital holographic microscope Only the real information can be extracted through the filtering process. However, this filtering process causes a lot of information loss. Conventional inline digital holographic microscopes do not require a filtering process, so that information loss can be minimized, but it is impossible to completely remove DC information and false information.

In order to solve this problem, there has been proposed a quadruple method (JP-A-10-2008-0086309) in which DC information is removed by using two hologram images. However, this technique uses a DC signal There is a problem that it is impossible to completely remove the DC information and the virtual image information.

Published Patent Publication No. 10-2008-0086309 (Published on September 25, 2008)

According to an embodiment of the present invention, in order to solve the problems of the related art, DC information and false image information are completely removed without loss of the stereoscopic information of the object, and real information of the object in which the DC information and false image information are completely removed is used And it is an object of the present invention to provide an apparatus and a method for accurately measuring the refractive index error of a microlens.

According to an embodiment of the present invention, there is provided a method of detecting a refractive index error of a microlens performed by an apparatus for detecting a refractive index error of a microlens, comprising the steps of: (a) Acquiring an object hologram image of the object; (b) obtaining real-world information about the object by removing noise included in the plurality of object hologram images using light intensity values of the plurality of object hologram images; (c) extracting phase information of the object using the real-world information; And (d) detecting the presence or absence of a defect in the microlens by calculating a refractive index error between a design value and a measured value of a refractive index of the microlens using the phase information of the object, Each of the object hologram images has a different phase.

In addition, the noise is DC (Direct Current) information and virtual image information included in each object hologram image.

The object is characterized by being a combination of a matting solution and a microlens contained in the matting solution.

The step (a) includes the steps of: (a-1) transmitting light emitted from a light source to a microlens contained in a matching solution; (a-2) generating an interference wavelength with respect to light transmitted through the microlens through a prism; (a-3) transitioning the phase of the interference wave using at least one optical modulator; And (a-4) obtaining the object hologram image by causing the phase-shifted interference wave to enter the charge coupled device.

In the step (a), the four object hologram images are obtained by repeating the steps (a-1) to (a-4), and the phases shifted in the step (a- 3) And obtaining four object hologram images having different phases from each other.

The step (b) may further include: (b-1) calculating a light intensity value of the plurality of object hologram images; And (b-2) acquiring real-world information on the object by removing DC information and virtual image information included in the plurality of object hologram images through calculation between the respective light intensity values .

The step (b-1) may include acquiring light intensity values of the plurality of object hologram images using the mathematical values of the two lights constituting the mathematical expression values of the plurality of object hologram images. And the two lights are two lights having an interference wavelength generated in order to obtain the object hologram image in the step (a).

When the plurality of object hologram images are composed of a first object hologram image, a second object hologram image, a third object hologram image, and a fourth object hologram image, the (b-2) Calculating a difference between an added value and a subtracted value of light intensity values of the second object hologram image and calculating a difference between an added value and a subtracted value of the light intensity values of the third and fourth object hologram images, Calculating a second difference value; And removing the DC information and the virtual image information included in the plurality of object hologram images using the first difference value and the second difference value to obtain actual information about the object.

In the step (c), the phase information of the object is acquired using the imaginary part and the real part of the real information.

The step (d) may include extracting thickness information for an object from the phase information of the object in the step (c); And calculating the refractive index error using the phase information of the object in the step (c), the wavelength information of the light emitted from the light source, the refractive index design value of the microlens, and the refractive index value of the matching solution. .

On the other hand, a computer-readable recording medium on which the computer program code for performing the above-described method of detecting the refractive index error of the microlens is recorded can be provided.

According to another aspect of the present invention, there is provided an apparatus for detecting refractive error of a microlens, including: an object hologram image acquiring unit acquiring a plurality of object hologram images for one object using an inline single optical axis interferometer including a microlens; A real image information obtaining unit for obtaining actual image information on the object by removing noise included in the plurality of object hologram images using the light intensity values of the plurality of object hologram images; An object phase information extracting unit for extracting phase information of an object using the real world information; And an index error detector for detecting the presence or absence of a defect in the microlens by calculating a refractive index error between a design value and a measured value of a refractive index of the microlens using the phase information of the object, Each of the hologram images has a different phase.

In addition, the noise is DC (Direct Current) information and virtual image information included in each object hologram image.

The object hologram image obtaining unit may include a light source; A microlens contained in a matching solution into which light emitted from the light source is incident; An objective lens and a convex lens for converting the light transmitted through the microlens into a plane wave; An objective lens and a convex lens, and the interference light is generated by reflecting the light of some of the light transmitted through the objective lens and the convex lens to form reflected light and transmitting the remaining light to form transmitted light, part; At least one optical modulator for shifting the phase of the generated interference wave; And a charge coupling device for acquiring an object hologram image from the interference wave emitted from the at least one optical modulator.

Further, the interference wavelength generator may be formed of a prism to generate an interference wavelength on one surface of the prism.

In addition, the optical modulator sets a phase angle for transiting the interference wavelength differently each time an interference wavelength for acquiring each object hologram image is incident. The charge coupled device has four And acquires the object hologram image.

The real image information obtaining unit may further include: a light intensity calculating unit that calculates a light intensity value for the plurality of object hologram images; And a noise removing unit removing the DC information and the virtual image information included in the plurality of object hologram images through calculation between the respective light intensity values to obtain actual information about the object.

The light intensity calculator may acquire light intensity values of the plurality of object hologram images using the mathematical values of the reflected light and the transmitted light forming the plurality of object hologram images.

When the plurality of object hologram images are composed of the first object hologram image, the second object hologram image, the third object hologram image, and the fourth object hologram image, Calculating a difference between an addition value and a subtraction value between the light intensity values of the image and calculating a difference between the addition value and the subtraction value between the light intensity values of the third and fourth object hologram images, Calculating a difference value, removing the DC information and the virtual image information included in the plurality of object hologram images using the first difference value and the second difference value, and obtaining actual information about the object.

The object phase information extraction unit may obtain phase information of the object using the imaginary part and the real part of the real information.

The refractive index error detecting unit may extract thickness information of the object from the phase information of the object and may include information on the phase of the object, the depth information, wavelength information of the light emitted from the light source, And the refractive index error is calculated using the refractive index value of the matching solution.

The method and apparatus for detecting a refractive index error of a microlens according to an embodiment of the present invention proposes a phase shift method using an optical modulator based on an inline single optical axis interferometer to completely remove DC information and false information without loss of 3D shape information of the object Only real information can be obtained, and the refractive index error of the microlens included in the inline single optical axis interferometer can be calculated using the real information. In addition, it is possible to judge whether the microlens is defective based on the refractive index error value. Such a technique can be used for judging whether a microlens applied to a camera, which is commonly used in a smart terminal, is defective or not.

1 is a block diagram of an internal configuration of an apparatus for detecting a refractive index error of a microlens according to an embodiment of the present invention.
2 is a structural view of an internal configuration of an object hologram image obtaining unit according to an embodiment of the present invention.
3 is a conceptual diagram for explaining a principle of generating an interference wavelength through a prism according to an embodiment of the present invention.
4 is a block diagram of an internal configuration of a real-world information acquisition unit according to an embodiment of the present invention.
5 is a flowchart illustrating a method of detecting a refractive index error of a microlens according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is also referred to as "including" an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated to the contrary.

Hereinafter, a refractive index error detecting apparatus 100 for a microlens according to an embodiment of the present invention will be described in detail with reference to FIG.

An apparatus 100 for detecting refractive error of a microlens according to an embodiment of the present invention includes an object hologram image obtaining unit 110, a real image information obtaining unit 120, an object phase information extracting unit 130, a refractive index error detecting unit 140 ).

The object hologram image obtaining unit 110 obtains the object hologram image. The object hologram image means a hologram image of an object to be extracted as a three-dimensional information. Here, the object hologram image obtaining unit 110 is configured based on an inline single optical axis interferometer. The inline single optical axis interferometer used in the present invention is a device capable of generating and reproducing a hologram image using only object light incident side by side without reference light. Wherein the in-line single optical axis interferometer transitions the phase of the interference wavelength through at least one optical modulator disposed in the same line.

Hereinafter, the configuration of the object hologram image obtaining unit 110 will be described with reference to FIG. The object hologram image acquisition unit 110 is a transmission type digital holographic microscope based on an inline single optical axis interferometer and includes a light source 111, a microlens 112a, a matching solution 112b, an objective lens 113, a single convex lens 114 An interference wavelength generator 115, a first optical modulator 116a, a second optical modulator 116b, an optical modulator controller 116c, and a charge coupled device 117. [

First, the light source 111 emits light, and the emitted light transmits the microlens 112a. The microlens 112a is contained in the matching solution 112b and the matching solution 112b can be selected to have the same or similar refractive index as that of the microlens 112a.

Hereinafter, the objective object for acquiring the hologram image in the present invention is a combination of the matching solution 112b and the microlens 112a contained therein. That is, the object made up of the combination is a target object for acquiring the hologram image in the present invention. Thus, in the following, the object means a combination of the microlens 112a and the matching solution 112b.

Then, the light transmitted through the microlens 112a proceeds to the objective lens 113. [ The light having passed through the objective lens 113 is converted into a plane wave by the one-sided convex lens 114, and is incident on the interference wavelength generation section 115.

The interference wavelength generation unit 115 is composed of a prism and divides the incident light into two lights to generate interference wavelengths (i.e., interference fringes). 3, the incident light can be divided into reflected light that is reflected from one side of the prism and transmitted light that passes through one side of the prism. At this time, the transmitted light is reflected twice at an angle of 30 [micro] in the prism, and is incident on one surface of the prism, and is exited to the outside of the prism. At this time, the reflected light and the transmitted light meet to form an interference wavelength. Here, the prism may be arranged so as to have an angle of 60 degrees from the reference plane, and the incident light may be arranged to be incident at an angle of 30 degrees with respect to the normal to one surface of the prism.

In order for the interference fringes formed by the interference wavelength to be sharp, the intensities of the reflected light and the transmitted light must be the same. Therefore, in order to set the intensities of the reflected light and the transmitted light to be equal to each other, it may be set to have about 0.68 and about 0.32, respectively. Here, the transmittance and the reflectance of the prism can be selected as appropriate values in order to set the intensities of the reflected light and the transmitted light to be the same, depending on the shape and properties of the prism used. In addition, the inner surface of the prism may be coated with a metal to minimize light loss when transmitted light is reflected inside the prism.

Subsequently, the interference wavelengths exiting the prism are incident on the first and second optical modulators 116a and 116b. Each of the first and second optical modulators 116a and 116b is a device for shifting the phase of light, and each of the optical modulators 116a and 116b can be designed to shift the interference wavelength to a different phase. Here, the optical modulators may be constituted by a wave plate as required. At this time, the phase angle at which the first and second optical modulators 116a and 116b transit the interference wavelength may be controlled by the optical modulator control unit 116c. The optical modulator control unit 116c may control the first and second optical modulators 116a and 116b to shift the interference wavelengths in different phases each time an interference wavelength for generating the object hologram image is incident. Accordingly, when a plurality of object hologram images are generated, each object hologram image is phase-shifted by the optical modulator so that each object hologram image has a different phase.

The interference wavelengths passing through the first and second optical modulators 116a and 116b are incident on the charge coupled device 117 and the charge coupled device 117 acquires the object hologram image from the interference wavelength. A charge-coupled device (CCD) 117 is a device that acquires an image by converting light into electric charges, and records the interference wavelength to generate an object hologram image.

The object hologram image obtained by the charge coupled device 117 can be expressed as Equation (1).

과

는 제 1 광변조기(116a)와 제 2 광변조기(116b)에 의해 각각 천이된 위상 정도를 의미하며,

과

는 간섭파장 생성부(115)에서 생성된 반사광과 투과광을 각각 의미한다. 반사광과 투과광을 프레넬 회절 이론을 기반으로 수식적으로 표현하면 하기 수학식2 및 수학식3과 같이 나타낼 수 있다.here

and

Quot; means a phase angle shifted by the first optical modulator 116a and the second optical modulator 116b, respectively,

and

Respectively, the reflected light and the transmitted light generated by the interference wavelength generating unit 115, respectively. The reflected light and the transmitted light can be expressed as Equation 2 and Equation 3 by formulas based on Fresnel diffraction theory.

,

,

는 객체의 좌표정보,

,

는 상수를 의미한다.Where k is the wave number,

,

,

The coordinate information of the object,

,

Is a constant.

Each of the object hologram images may be generated to have different phases by the first and second optical modulators 116a and 116b. For example, when a first object hologram image is generated, the first optical modulator 116a has no phase shift angle and the second optical modulator 116b can set a phase shift angle of -π / 2, When a two-object hologram image is generated, the first optical modulator 116a has no phase shift angle and the second optical modulator 116b can set a phase shift angle of pi / 2, and a third object hologram image is generated A phase shift angle of? / 2 may be set for the first optical modulator 116a and a phase shift angle of -π / 2 for the second optical modulator 116b may be set, and a fourth object hologram image may be generated The phase shift angles of? / 2 can be set for the first optical modulator 116a and the second optical modulator 116b. As a result, the first through fourth object hologram images may have phase delay angles of 0,? / 2,?, 3? / 2, respectively. Here, the phase shift angles of the first optical modulator 116a and the second optical modulator 116b are phase shift angles that form a phase delay angle between object hologram images of 0, π / 2, π, and 3π / Each angle can be set as required.

The first through fourth object hologram images are sequentially represented by mathematical formulas (4), (5), (6) and (7).

Then, the actual information obtaining unit 120 obtains the light intensity values for the first through fourth object hologram images, and removes the noise included in the first through fourth object hologram images using the light intensity values, And acquires actual information about the object included in the fourth object hologram image. For this, the real image information obtaining unit 120 may include a light intensity calculating unit 121 and a noise removing unit 122 as shown in FIG.

)과 제 2 객체 홀로그램영상(

)의 광강도값을 수식적으로 표현하면 하기 수학식 8과 같이 나타낼 수 있다. 수학식 8은 제 1 객체 홀로그램영상(

)의 광강도값과 제 2 객체 홀로그램영상(

)의 광강도값 간의 가산값과 감산값을 나타내는 수식이다.The light intensity calculator 121 calculates light intensity values (i.e., light intensity values) regarding the interference wavelengths forming the hologram image with respect to the first through fourth object hologram images. At this time, the first object hologram image (

) And the second object hologram image (

) Can be expressed as Equation (8). &Quot; (8) " Equation (8) represents the first object hologram image

) And the second object hologram image (

) ≪ / RTI &

,

,

은 복원 평면의 좌표, C 는 상수를 의미한다. 여기서 상기 수학식 8의 좌변의

기호와 우변의

기호는 순서대로 조합되는 것으로, 다시 말하면 좌변의 기호가 + 인 경우 우변의 기호는 - 가 되는 것이다.Where k is the wave number,

,

,

Is the coordinate of the restoration plane, and C is a constant. Here, the left side of Equation (8)

Symbol and right side

Symbols are combined in order, that is, if the symbol on the left side is +, the symbol on the right side is -.

과

의 광강도값을 수식적으로 표현하면 하기 수학식 9와 같이 나타낼 수 있다. 수학식 9는 제 3 객체 홀로그램영상(

)의 광강도값과 제 4 객체 홀로그램영상(

)의 광강도값 간의 가산값과 감산값을 나타내는 수식이다. 여기서 하기 수학식 9에 있어서도 좌변의

기호와 우변의

기호는 순서대로 조합되는 것으로, 다시 말하면 좌변의 기호가 + 인 경우 우변의 기호는 + 가 되는 것이다.In the same way,

and

Can be expressed as Equation (9). &Quot; (9) " Equation (9) represents the third object hologram image

) And the fourth object hologram image (

) ≪ / RTI & Here, also in the following equation (9)

Symbol and right side

Symbols are combined in order, that is, when the symbol on the left side is +, the symbol on the right side is +.

)과 감산값(

)간의 차를 산출한 제1 차이값(

)을 연산한다. 상기 제1 차이값(

)은 하기 수학식 10과 같다. Then, the noise removing unit 122 corrects DC (Direct Current) information (information on the zero-order diffracted light) included in the object hologram image using the light intensity values of the respective hologram images obtained from the light intensity calculating unit 121, And virtual image information are removed to obtain real image information. Specifically, the noise removing unit 122 may calculate an addition value (i.e., a difference value) between the light intensity values of the first object hologram image and the second object hologram image

) And a subtraction value

) Of the first difference value (

). The first difference value (

) Is expressed by the following equation (10).

)과 감산값(

) 간의 차를 산출한 제 2 차이값(

)을 연산한다. 제 2 차이값(

)은 하기 수학식 11과 같다.Next, the noise removing unit 122 calculates an addition value between the light intensity values of the third and fourth object hologram images

) And a subtraction value

) Of the first difference value (

). The second difference value (

) ≪ / RTI >

Then, the noise removing unit 122 obtains a final complex hologram by adding Equations (10) and (11). Here, the final complex hologram includes only the real image information of the object by removing the DC information and the virtual image information, and the formula for the final complex hologram is shown in Equation (12).

As a result, the noise removing unit 122 can obtain only real information of the object by removing the DC information and the virtual image information as shown in Equation (12). That is, the noise removing unit 122 may obtain the final complex hologram (Uo) of the object corresponding to the real image information of the object.

The object phase information extraction unit 130 calculates the phase information of the object using the acquired real image information. The phase information of the object can be expressed by Equation (13).

는 상기 DC정보와 허상 정보가 제거된 최종 복소 홀로그램(Uo)의 위상 정보를 나타내며,

은 상기 DC정보와 허상 정보가 제거된 최종 복소 홀로그램의 허수부,

는 상기 DC정보와 허상 정보가 제거된 최종 복소 홀로그램의 실수부를 나타낸다.

Represents the phase information of the final complex hologram (Uo) from which the DC information and the virtual image information are removed,

An imaginary part of the final complex hologram from which the DC information and the virtual image information are removed,

Represents the real part of the final complex hologram from which the DC information and the virtual image information are removed.

The refractive index error detector 140 detects the refractive index error using the phase information to determine whether the microlens 112a is defective or not. More specifically, the refractive index error detector 140 applies the phase spreading algorithm to the acquired phase information to compensate for the distorted phase information. At this time, the phase information of the object can be expressed by Equation (14).

은 객체의 두께 정보를 의미하고,

는 광원(111)에서 출사된 광의 파장길이,

은 굴절률 차이를 의미한다. 여기서

는 수학식 15와 같이 나타낼 수 있다.

Is the thickness information of the object,

The wavelength of the light emitted from the light source 111,

Means a refractive index difference. here

Can be expressed by Equation (15).

은 굴절률의 오차를 의미하고,

은 마이크로 렌즈(112a)의 굴절률 설계값,

는 정합 용액(112b)의 굴절률값을 의미한다. 그리고 수학식15를 수학식14에 적용할 경우 굴절률 오차(

)는 수학식16과 같이 정리될 수 있다

Denotes an error of the refractive index,

The design value of the refractive index of the microlens 112a,

Means the refractive index value of the matching solution 112b. When Equation (15) is applied to Equation (14), the refractive index error

) Can be rearranged as shown in Equation (16)

) 는 상기 수학식 13을 이용하여 산출될 수 있고, 이를 상기 수학식 16에 대입하여 굴절률 오차(

)를 산출할 수 있다. 또한 상기 객체의 두께 정보(

)는 렌즈 설계 시 렌즈 방정식을 통해 산출될 수 있다. 또한 광원의 파장길이(

), 마이크로 렌즈(112a)의 굴절률 설계값(

), 정합 용액(112b)의 굴절률값(

)은 미리 아는 값이다. 따라서 상기 수학식 16과 같이 객체의 위상 정보(

), 객체의 두께 정보(

), 광원의 파장길이(

), 마이크로 렌즈(112a)의 굴절률 설계값(

), 정합 용액(112b)의 굴절률값(

)를 이용하여 굴절률 오차(

)가 산출될 수 있다.Here, the phase information of the object

) Can be calculated using Equation (13), which is substituted into Equation (16) to obtain a refractive index error

) Can be calculated. The thickness information of the object

) Can be calculated through lens equation during lens design. The wavelength length of the light source (

), The design value of the refractive index of the microlens 112a (

), The refractive index value of the matching solution 112b (

) Is a known value. Therefore, the phase information of the object

), Object thickness information (

), The wavelength length of the light source (

), The design value of the refractive index of the microlens 112a (

), The refractive index value of the matching solution 112b (

) Was used to calculate the refractive index error (

) Can be calculated.

)는 마이크로 렌즈의 굴절률의 설계값과 측정값 간의 차이를 의미하는 것으로서, 수학식 16에서 마이크로 렌즈(112a)의 굴절률 설계값과 정합 용액(112b)의 굴절률값이 완벽히 일치할 경우, 수학식 16의 굴절률 오차는 0이 된다. 만약 굴절률 오차가 0이 되지 않는 다면, 마이크로 렌즈(112a)에 굴절률 오차가 존재한다는 것을 의미하게 된다. 이를 통하여 굴절률 오차 검출부(140)는 마이크로 렌즈(112a)의 결함존재 여부를 판단할 수 있다. Refractive index error (

Represents the difference between the design value and the measured value of the refractive index of the microlens. When the refractive index design value of the microlens 112a perfectly matches the refractive index value of the matching solution 112b in Equation (16) The refractive index error of the refractive index is 0. If the refractive index error does not become zero, it means that a refractive index error exists in the microlens 112a. The refractive index error detector 140 can determine whether or not a defect exists in the microlens 112a.

In the conventional inline digital holographic microscope, the information loss can be minimized because the DC information and the virtual image information are not filtered out. However, there is a problem that DC information and false information can not be completely removed. The division method could not completely remove the DC information and the false information. However, according to an embodiment of the present invention, a refractive index error detecting method and a detecting apparatus of a microlens 112a propose a phase shift method using an optical modulator based on an inline single optical axis interferometer, Information of the microlenses 112a included in the in-line single optical axis interferometer can be calculated using real information. The defect of the micro lens 112a can be determined based on the refractive index error value. This technique can be used to determine whether the micro lens 112a included in the camera, which is often installed in a smart terminal, is defective.

Hereinafter, a method of detecting a refractive index error of the microlens 112a according to an embodiment of the present invention will be described in detail with reference to FIG. The method described below is performed by the apparatus 100 for detecting a refractive index error of a microlens according to an embodiment of the present invention, and may include all of the items described above even if omitted below .

First, the refractive index error detecting device 100 of the microlens acquires a plurality of object hologram images having different phases using an in-line single optical axis interferometer including a microlens 112a (S110). The inline single optical axis interferometer includes at least one optical modulator capable of shifting the phase of the interference wavelength (or interference fringe) so that the phase of the different angles is changed each time each object hologram image is acquired. Preferably, when four object hologram images are obtained, the phase difference of each object hologram image may be 0,? / 2,?, 3? / 2.

Next, the refractive index error detecting apparatus 100 of the microlens calculates a light intensity value for a plurality of object hologram images (S120). The light intensity value is an intensity value for the light forming the interference wavelength that generates each object hologram image.

The refractive index error detecting apparatus 100 of the microlens obtains real image information by removing DC information and virtual image information from a plurality of object hologram images using a light intensity value (S130). In other words, the DC information and the virtual image information are removed, and the final complex hologram information including real image information about the object can be obtained.

Then, the refractive index error detecting apparatus 100 of the microlens extracts the phase information of the object using the actual information (S140). The phase information of the object can be extracted by using the imaginary part and the real part of the final complex hologram mathematical value forming the real information.

The refractive index error detecting apparatus 100 of the microlens calculates the refractive index error of the microlens 112a using the phase information of the object (S150). The refractive index error equation may be composed of the phase information of the object, the thickness information of the object, the wavelength length of the light emitted from the light source 111, the refractive index design value of the microlens 112a, and the refractive index value of the matching solution. At this time, the refractive index error has a value of 0 only when the refractive index design value of the microlens 112a and the refractive index value of the matching solution perfectly match.

Finally, the refractive index error detecting apparatus 100 of the microlens may determine that there is no defect when the refractive index error is zero, and may determine that there is a defect if it is not zero (S160) .

The method of an embodiment of the present invention described with reference to FIG. 5 may also be implemented in the form of a recording medium including instructions executable by a computer, such as program modules, being executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, the computer-readable medium can include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes any information delivery media, including computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transport mechanism.

The method according to an embodiment of the present invention may also be implemented as a computer program (or a computer program product) including instructions executable by a computer. A computer program includes programmable machine instructions that are processed by a processor and can be implemented in a high-level programming language, an object-oriented programming language, an assembly language, or a machine language . The computer program may also be recorded on a computer readable recording medium of a type (e.g., memory, hard disk, magnetic / optical medium or solid-state drive).

Thus, a method according to an embodiment of the present invention may be implemented by a computer program as described above being executed by a computing device. The computing device may include a processor, a memory, a storage device, a high-speed interface connected to the memory and a high-speed expansion port, and a low-speed interface connected to the low-speed bus and the storage device. Each of these components is connected to each other using a variety of buses and can be mounted on a common motherboard or mounted in any other suitable manner.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the embodiments described above are illustrative and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

100: refractive index error detection device of microlens
110: object hologram image acquisition unit
120: actual information acquisition unit
130: Object phase information obtaining unit
140: refractive index error detector

Claims (21)

A method for detecting a refractive index error of a microlens,
(a) acquiring a plurality of object hologram images for one object using an in-line single optical axis interferometer;
(b) obtaining real-world information about the object by removing noise included in the plurality of object hologram images using light intensity values of the plurality of object hologram images;
(c) extracting phase information of the object using the real-world information; And
(d) calculating a refractive index error between a design value and a measured value of the refractive index of the microlens using the phase information of the object to detect the presence or absence of a defect in the microlens,
Wherein the plurality of object hologram images have different phases from each other. The method according to claim 1,
Wherein the noise is direct current (DC) information and virtual image information included in each of the object hologram images. The method according to claim 1,
Wherein the object is a combination of a matched solution and a microlens contained in the matched solution. The method according to claim 1,
The step (a)
(a-1) transmitting light emitted from a light source to a microlens contained in a matching solution;
(a-2) generating an interference wavelength with respect to light transmitted through the microlens through a prism;
(a-3) transitioning the phase of the interference wave using at least one optical modulator; And
(a-4) obtaining the object hologram image by causing the phase-shifted interference wave to enter the charge coupled device;
Wherein the refractive index of the microlens is less than the refractive index of the microlens. 5. The method of claim 4,
The step (a)
Four object hologram images are obtained by repeating the steps (a-1) to (a-4), and four objects having different phases are set by repeating steps (a-3) A method of detecting a refractive index error of a microlens, comprising the step of acquiring a hologram image. The method according to claim 1,
The step (b)
(b-1) calculating light intensity values for the plurality of object hologram images; And
(b-2) acquiring actual information about the object by removing DC information and virtual image information included in the plurality of object hologram images through calculation between the respective light intensity values;
Wherein the refractive index of the microlens is less than the refractive index of the microlens. The method according to claim 6,
Wherein the step (b-1)
And acquiring light intensity values of the plurality of object hologram images using the mathematical values of the two lights constituting the mathematical expression of the plurality of object hologram images,
The method of claim 1, wherein the two light beams are two beams of interference light generated to obtain the object hologram image in step (a). 8. The method of claim 7,
The step (b-2)
When the plurality of object hologram images are composed of a first object hologram image, a second object hologram image, a third object hologram image, and a fourth object hologram image,
Calculating a first difference value by calculating a difference between an added value and a subtracted value between the light intensity values of the first and second object hologram images and calculating an addition value between the light intensity values of the third and fourth object hologram images, Calculating a second difference value that is a difference between values; And
Removing the DC information and the virtual image information included in the plurality of object hologram images using the first and second difference values to obtain actual information about the object, . The method according to claim 1,
The step (c)
And obtaining the phase information of the object using the imaginary part and the real part of the real image information. 5. The method of claim 4,
The step (d)
And calculating the refractive index error using the phase information of the object in the step (c), the wavelength information of the light emitted from the light source, the refractive index design value of the microlens, and the refractive index value of the matching solution. Of the refractive index of the first layer. An object hologram image acquiring unit for acquiring a plurality of object hologram images for one object using an inline single optical axis interferometer;
A real image information obtaining unit for obtaining actual image information on the object by removing noise included in the plurality of object hologram images using the light intensity values of the plurality of object hologram images;
An object phase information extracting unit for extracting phase information of an object using the real world information; And
And a refractive index error detector for detecting the presence or absence of a defect in the microlens by calculating a refractive index error between a design value and a measured value of the refractive index of the microlens using the phase information of the object,
Wherein each of the plurality of object hologram images has a different phase. 12. The method of claim 11,
Wherein the noise is direct current (DC) information and virtual image information included in each of the object hologram images. 12. The method of claim 11,
Wherein the object is a combination of a matched solution and a microlens contained in the matched solution. 12. The method of claim 11,
Wherein the object hologram image obtaining unit comprises:
Light source;
A microlens contained in a matching solution into which light emitted from the light source is incident;
An objective lens and a convex lens for converting the light transmitted through the microlens into a plane wave;
An objective lens and a convex lens, and the interference light is generated by reflecting the light of some of the light transmitted through the objective lens and the convex lens to form reflected light and transmitting the remaining light to form transmitted light, part;
At least one optical modulator for shifting the phase of the generated interference wave; And
A charge coupling device for acquiring an object hologram image from an interference wavelength emitted from the at least one optical modulator;
And a refractive index difference of the microlenses. 15. The method of claim 14,
Wherein the interference wavelength generator is formed of a prism, and generates an interference wavelength on one side of the prism. 16. The method of claim 15,
Wherein the optical modulator sets a phase angle for transiting the interference wavelength differently each time an interference wavelength for acquiring each object hologram image is incident,
Wherein the charge coupled device acquires four object hologram images from four interference wavelengths having different phases. 15. The method of claim 14,
Wherein the real-
A light intensity calculation unit for calculating a light intensity value for the plurality of object hologram images; And
Removing the DC information and the virtual image information included in the plurality of object hologram images through calculation between the respective light intensity values to obtain actual information about the object;
And a refractive index difference of the microlenses. 18. The method of claim 17,
The light intensity calculating unit may calculate,
And acquires light intensity values for the plurality of object hologram images using the mathematical values of the reflected light and the transmitted light forming the plurality of object hologram images. 19. The method of claim 18,
Wherein the noise eliminator comprises:
When the plurality of object hologram images are composed of a first object hologram image, a second object hologram image, a third object hologram image, and a fourth object hologram image,
Calculating a first difference value by calculating a difference between an added value and a subtracted value between the light intensity values of the first and second object hologram images and calculating an addition value between the light intensity values of the third and fourth object hologram images, Calculating a second difference value by calculating a difference between the first and second difference values, removing the DC information and the virtual image information included in the plurality of object hologram images using the first and second difference values, Wherein the refractive index difference of the microlens is set to be smaller than the refractive index of the microlens. 12. The method of claim 11,
Wherein the object phase information extracting unit comprises:
And obtains the phase information of the object using the imaginary part and the real part of the real image information. 15. The method of claim 14,
Wherein the refractive index error detecting unit comprises:
Wherein the refractive index error is calculated using the phase information of the object, the wavelength information of the light emitted from the light source, the refractive index design value of the microlens, and the refractive index value of the matching solution.

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