TWI770182B - Measurement system and measurement method - Google Patents

Abstract

A measurement system adapted to an object is provided. The measurement system includes a light source, two splitter elements, a light guide device, and two sensing elements. One of the splitter elements is disposed on a downstream of a light path of the light source. The light guide device is disposed on a downstream of a first light path of the one of the splitter elements. The other one of the splitter elements is disposed on a downstream of a first light path of the light guide device. One of the sensing elements is disposed on a downstream of a second light path of the one of the splitter elements. The other one of the sensing elements is disposed on a downstream of a first light path of the other one of the splitter elements. In addition, a measurement method is also provided.

Description

Measuring system and measuring method

The present invention relates to a measurement system and measurement method of an optical element.

With the increasing development of the technology industry, the types, functions and ways of using optical devices are becoming more and more diverse, and the use and matching of optical components are also becoming more and more extensive. In addition, due to the miniaturization trend of optical devices, the optical components used and matched also need to be miniaturized. Therefore, it is necessary to measure the optical components through precise instruments to maintain better optical quality.

However, in today's measurement technology, optical elements are mainly measured in a destructive measurement manner, for example, the optical elements are machined into a right-angle shape for optical measurement, thus resulting in waste of optical elements. In today's measurement technology, multiple light sources are often used as measurement light. As a result, measuring instruments are too complex and costly. In addition, there is also the problem of difficult optical correction. Therefore, how to design a relatively simple measuring instrument that does not consume optical components and its use method is a joint effort of those skilled in the art.

The invention provides a measurement system and measurement method, which can perform fast optical measurement, simplify the structure and reduce the cost, and can solve the problem that the traditional measurement method needs to destroy the object to be measured for measurement.

An embodiment of the present invention provides a measurement system suitable for measuring an object to be tested. The measurement system includes a light source, two light splitting elements, a light guide device and two sensing elements. One of the two light splitting elements is disposed downstream of the light path of the light source. The light guide device is arranged downstream of the first light path of one of the two light splitting elements. The other of the two light splitting elements is disposed downstream of the first light path of the light guide device. One of the two sensing elements is disposed downstream of the second optical path of one of the two light splitting elements. The other of the two sensing elements is disposed downstream of the first optical path of the other of the two light splitting elements. Therefore, the measurement system can confirm its optical properties by using a single light source to perform fast optical measurements on both sides of the object to be tested.

Another embodiment of the present invention provides a measurement method suitable for a test object. The measuring method includes the following steps: first, providing the first beam and the second beam of the measuring system to the opposite first and second surfaces of the object to be measured. Next, the first beam and the second beam reflected by the object to be tested are detected to obtain two first focusing coordinates of the first surface and the second surface. Finally, the shape and thickness of the object to be measured are calculated according to the two first focus coordinates.

Based on the above, in the measurement system and measurement method of the present invention, the measurement system can divide the light beam emitted by a single light source into a first light beam and a second light beam by means of a spectroscopic element, which are respectively placed on the first surface and the second light beam of the object to be measured. The focusing position of the first surface and the second surface is obtained by focusing on the surface, and then the optical information of the object to be measured is calculated from the focusing position information. In this way, in this embodiment, the measurement system only uses a single light source to perform fast optical measurement on the opposite sides of the object to be measured to confirm the optical properties, and the structure of the measurement system can be simplified and the cost thereof can be reduced. In addition, it can solve the problem that the traditional measurement method needs to destroy the object to be measured for measurement.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, the following embodiments are given and described in detail with the accompanying drawings as follows.

FIG. 1 is a schematic diagram of a measurement system according to an embodiment of the present invention. Referring to FIG. 1 , in this embodiment, the measurement system 100 is suitable for measuring an object to be measured 10 , and the object to be measured 10 is, for example, a non-planar lens such as a bi-concave lens, a bi-convex lens, a meniscus lens, a convex-concave lens, a plano-convex lens or a plano-concave lens, The present invention is not limited to the optical element whose surface has a curvature, such as a prism or an integrating cylinder. In this embodiment, the object to be tested 10 is, for example, a biconvex lens.

The measurement system 100 includes a light source 110, light splitting elements 120, 130, sensing elements 140, 150, and light guide devices 180_1, 180_2.

The light source 110 is an electronic device capable of emitting a light beam L, such as a laser device, but the present invention does not limit its type.

The beam splitting elements 120 and 130 are optical elements that can partially reflect and partially transmit the light beam L, such as beam splitters. In this embodiment, the beam splitting elements 120 and 130 are, for example, beam splitters with a transmittance ranging from 40% to 60%. In a preferred embodiment, the transmittance of the beam splitter is about 50%, but the present invention is not limited thereto.

The sensing elements 140 and 150 are electronic devices capable of detecting light intensity, such as photo detectors.

The light guiding devices 180_1 and 180_2 may be any device or optical element capable of guiding the light beam L to transmit in a specified direction. In this embodiment, the light guide devices 180_1 and 180_2 are, for example, two mirrors, but the present invention is not limited thereto.

In addition, more specifically, the measurement system 100 of this embodiment further includes objective lenses 170_1 , 170_2 , 170_3 , and 170_4 for focusing the light beam, but the present invention is not limited to this, and the number, type and type of the objective lenses are also Unrestricted.

In this embodiment, the light source 110 provides a light beam L. The light splitting element 120 is disposed downstream of the light path of the light source 110 . The light guide devices 180_1 and 180_2 are disposed downstream of the first optical path of the light splitting element 120 . The light splitting element 130 is disposed downstream of the first light path of the light guide devices 180_1 and 180_2. The sensing element 140 is disposed downstream of the second optical path of the light splitting element 120 . The sensing element 150 is disposed downstream of the first optical path of the light splitting element 130 , as shown in FIG. 1 .

In detail, in this embodiment, when the light beam L provided by the light source 110 is transmitted to the light splitting element 120 , the light beam L1 and the second light beam L2 are divided into the first light beam L1 and the second light beam L2 by the light splitting element 120 . The objective lens 170_1 is located between the spectroscopic element 120 and the object to be tested 10 , and is used for focusing the second light beam L2 transmitted by the spectroscopic element 120 on the object to be tested 10 . The objective lens 170_2 is located between the light splitting element 120 and the sensing element 140 , and is used for focusing the second light beam L2 reflected by the object to be tested 10 on the sensing element 140 . The objective lens 170_3 is located between the spectroscopic element 130 and the object to be tested 10 , and is used for focusing the first light beam L1 transmitted by the spectroscopic element 130 on the object to be tested 10 . The objective lens 170_4 is located between the light splitting element 130 and the sensing element 150 , and is used for focusing the first light beam L1 reflected by the object to be tested 10 on the sensing element 150 . The light guide devices 180_1 and 180_2 are located between the light splitting elements 120 and 130 for reflecting the first light beam L1 transmitted by the light splitting element 120 to the light splitting element 130 .

Before the measurement starts, the optical axis of the object to be measured 10 and the measurement system 100 can be corrected by a standard jig or image discrimination correction method, but the invention is not limited to this.

FIG. 2 is a schematic diagram of measuring a test object according to an embodiment of the present invention. Please refer to FIG. 1 and FIG. 2 at the same time, in the measurement process of this embodiment, the following measurement steps can be performed to measure the thickness of a shape of the object to be tested 10 . Shape thickness refers to the actual thickness of a single object shape. Specifically, the light source 110 provides a light beam L to the light splitting element 120, and the light beam L is transmitted and reflected in the light splitting element 120 to form the first light beam L1 and the second light beam L2, respectively. The first light beam L1 is transmitted by the light splitting element 120 and is reflected to the light splitting element 130 by the light guide devices 180_1 and 180_2, and then reflected to the objective lens 170_3 by the light splitting element 130, and is focused on the first surface S1 of the object to be tested 10 by the objective lens 170_3 on (ie focus C1). On the other hand, the second light beam L2 is reflected to the objective lens 170_1 by the beam splitting element 120, and is focused on the second surface S2 (ie, the focus C2) of the object to be tested 10 by the objective lens 170_1.

After the first light beam L1 and the second light beam L2 are respectively focused on the first surface S1 and the second surface S2 of the object to be measured 10, the first light beam L1 is reflected back to the objective lens 170_3 by the first surface S1 of the object to be measured 10, and is transmitted through The beam splitting element 130 is sent to the objective lens 170_4, and finally focused to the sensing element 150 through the objective lens 170_4. The second light beam L2 is reflected back to the objective lens 170_1 by the second surface S2 of the object to be tested 10 , transmitted through the beam splitting element 120 to the objective lens 170_2 , and finally focused to the sensing element 140 by the objective lens 170_2 , as shown in FIG. 1 .

Therefore, in the above measurement step, the first surface S1 and the second surface can be obtained by focusing the first light beam L1 and the second light beam L2 on the first surface S1 and the second surface S2 of the object to be measured 10 respectively. The focus position of S2, and then the shape and thickness of the object to be tested 10 can be calculated from the focus position information. In this way, in the present embodiment, the measurement system 100 can perform rapid optical measurement on the opposite sides of the object 10 to be measured by using only a single light source 110 to confirm its shape and thickness, and the structure of the measurement system 100 can be simplified and reduced. cost. In addition, since the measurement can be performed without destroying the object to be tested 10, the object to be tested 10 with a diameter of less than 10 mm can be measured.

In this embodiment, the measurement system 100 may further include a mobile platform 160 disposed between the spectroscopic elements 120 and 130 . The moving platform 160 is, for example, a platform device that can move one-dimensionally, two-dimensionally or three-dimensionally and a structure for fixing the object to be tested 10 , such as an optical element holder with a movable optical stage, but the present invention is not limited to this. The moving position of the object 10 is recorded by the moving platform 160 as coordinate information. Specifically, in the above measurement process, the object to be measured 10 is moved to focus the first light beam L1 on the first surface S1 and the object to be measured 10 is moved to focus the second light beam L2 on the second surface S2 to Record the position of the first surface S1 and the position of the second surface S2 as two first focus coordinates, and then calculate the shape and thickness of the object to be measured. However, in other embodiments, the device for moving the object under test 10 can also be provided by an additional fixture, and the present invention is not limited thereto.

In addition, after the above-mentioned measurement step, the above-mentioned measurement step can be performed on a reference object with a known shape and thickness, thereby obtaining two first focusing coordinates of the first beam L1 and the second beam L2 focused on the opposite sides of the reference object , and the shape and thickness of the object to be tested 10 are calculated based on the difference between the two first focus coordinates of the object to be tested 10 and the reference object, but the invention is not limited to this.

FIG. 3 is a schematic diagram of measuring a test object according to another embodiment of the present invention. Please refer to FIG. 1 and FIG. 3 at the same time. In the measurement process of the present embodiment, subsequent measurement steps may be performed after the shape and thickness of the object to be tested 10 is obtained, so as to further measure the material thickness of the object to be tested 10 . The material thickness refers to the thickness measured when the light beam travels in the object to be tested 10 and is influenced by the refractive index of the object to be tested 10 , and the thickness of the material is different from the thickness of the shape. Specifically, the first light beam L1 provided by the light source 110 is used to form a focus point (ie, the focus point C1 ) on the first surface S1 of the object to be tested 10 , and the object to be tested 10 is moved toward the objective lens 170_3 to make the first light beam L1 The focal point is transferred from the first surface S1 of the object to be tested 10 to the second surface S2 of the object to be tested 10 (ie, the focus C2 ). Therefore, the sensing element 150 can detect the first light beam L1 reflected by the object to be tested 10 to obtain two second focusing coordinates of the first surface S1 and the second surface S2.

In this way, in the above-mentioned measurement step, the focusing of the first surface S1 and the second surface S2 can be obtained by focusing the first light beam L1 on the first surface S1 and the second surface S2 of the object 10 respectively. position, and then the material thickness of the object to be tested 10 is calculated from the focus position information. In this step, the material thickness of the object to be tested 10 can also be calculated by comparing with the material thickness of the reference object. The comparison method of the thickness difference is similar to the comparison method in the aforementioned measurement step, so it is not repeated here.

FIG. 4 is a schematic diagram of measuring a test object according to another embodiment of the present invention. Please refer to FIG. 1 and FIG. 4 at the same time. In the measurement process of this embodiment, subsequent measurement steps can be performed after the material thickness of the object to be tested 10 is obtained, so as to further measure a radius of curvature of one surface of the object to be tested 10 . Specifically, the first light beam L1 provided by the light source 110 is used and the object to be tested 10 is moved so that the spherical center of a focusing element is coincident with the spherical center R of the first surface S1 of the object to be tested 10 . When the focusing element coincides with the spherical center of the object to be tested 10 , the first light beam L1 will be totally reflected on the first surface S1 of the object to be tested 10 . In this embodiment, the focusing element is the objective lens 170_3, but in other embodiments, a focusing element with a known radius of curvature may be additionally configured for measurement, and the present invention is not limited thereto.

In this way, in the above measurement step, the position of the first surface S1 can be obtained by the first light beam L1 reflected by the object to be tested 10 , and then the radius of curvature of the object to be tested 10 can be calculated from the reflected position information. . The comparison method of the difference between the curvature radius of the object to be tested 10 and the curvature radius of the focusing element is similar to the comparison method in the aforementioned measurement steps, so it is not repeated here.

-----------------------------(1) 其中： n₀ ：空氣的折射率； n：待測物的折射率； l₁ ：待測物的形狀厚度； l₂ ：待測物的材質厚度； r：待測物的第一面的曲率半徑。In addition, in this embodiment, the refractive index of the object to be measured 10 can be further obtained through formula calculation according to the shape thickness, material thickness and curvature radius obtained by the above three measurement steps. Specifically, the refractive index can be defined according to the following formula (1):

-----------------------------(1) Among them: n ₀ : the refractive index of air; n: the refractive index of the object to be measured ; l ₁ : the shape and thickness of the object to be tested; l ₂ : the thickness of the material of the object to be tested; r: the radius of curvature of the first surface of the object to be tested.

In this way, in the above-mentioned three different measurement steps in this embodiment, the measurement system 100 can measure the object to be measured 10 by using only a single light source 110 to perform fast optical measurement to confirm its optical properties, and then obtain the measurement of the object to be measured 10 . The shape thickness, material thickness, curvature radius and its refractive index can simplify the structure of the measurement system 100 and reduce its cost.

In addition to the above measurement steps, the light source 110 in this embodiment can be further replaced to provide another light beam with a different wavelength for optical measurement. Specifically, the first light beam L1 and another light beam (not shown) are respectively provided to form a focal point (ie, the focal point C1 ) on the first surface S1 of the object to be tested 10 , and the object to be tested is moved under the light beams of different wavelengths. The object 10 faces the objective lens 170_3 so that the focal point is transferred from the first surface S1 of the object to be tested 10 to the second surface S2 of the object to be tested 10 (ie, the focus C2 ), and then the two angles of the object to be tested 10 under different wavelength beams are obtained. Material thickness. Therefore, the Abbe value of the object to be tested 10 can be calculated according to the measurement method.

In addition to the above-mentioned measurement steps, the measurement system of this embodiment may further mount a temperature control module, which is arranged on the object to be tested 10 , so as to change the temperature of the object to be tested 10 . For example, the temperature control module is, for example, a heatable electronic device, a heat pipe or other heating devices in various forms, but the present invention is not limited thereto. In this way, the above-mentioned optical measurement can be performed under the condition that the object to be tested 10 is at different temperatures, and then the change value of the refractive index of the object to be tested 10 under different temperatures can be obtained.

FIG. 5 is a flow chart of steps of a measurement method according to an embodiment of the present invention. Please refer to FIG. 1 and FIG. 5 , the measurement method of this embodiment can be applied to at least the measurement apparatus 100 of FIG. 1 . Therefore, the measurement apparatus 100 of the embodiment of FIG. 1 will be used as an example below, but the present invention is not limited thereto. In this embodiment, step S500 is first performed to provide the first light beam L1 and the second light beam L2 of the measurement system 100 to the opposite first surface S1 and the second surface S2 of the object to be measured 10 . Next, step S510 is performed to detect the first light beam L1 and the second light beam L2 reflected by the object to be tested 10 to obtain two first focusing coordinates of the first surface S1 and the second surface S2. Next, step S520 is performed to calculate the shape and thickness of the object to be tested 10 according to the two first focus coordinates. In this way, the shape and thickness of the object to be tested 10 can be obtained through the above measurement steps.

After the above step S520 is completed, the user may optionally proceed to step S530 as required, providing the first beam L1 and moving the object 10 to make the focus of the first beam L1 shift from the first surface S1 of the object 10 to the second side S2 of the object to be tested 10 . Next, step S540 is performed to detect the first light beam L1 reflected by the object to be tested 10 to obtain two second focus coordinates of the first surface S1 and the second surface S2. Next, step S550 is performed to calculate the material thickness of the object to be tested 10 according to the two second focus coordinates. In this way, the material thickness of the object to be tested 10 can be obtained through the above measurement steps.

After completing the above step S550, the user can optionally proceed to step S560 as required, providing the first light beam L1 and moving the object 10 to be tested so that the spherical center of the focusing element (ie the objective lens 170_1 or the objective lens 170_3) coincides with the first surface The center of the S1. Next, step S570 is performed to detect the first light beam L1 reflected by the object to be tested 10 to obtain the curvature radius of the first surface S1 . In this way, the curvature radius of one surface of the object to be tested 10 can be obtained through the above-mentioned measuring steps.

After completing the above step S570 , the user may optionally proceed to step S580 as required, and obtain the refractive index value of the object to be tested 10 according to the shape, thickness and material thickness of the object to be tested 10 and the radius of curvature of the first surface S1 . In other words, the calculation of the above formula (1) is performed on the optical information of the object to be tested 10 obtained in steps S520 , S550 and S570 to obtain the refractive index value of the object to be tested 10 .

To sum up, in the measurement system and measurement method of the present invention, the measurement system can divide the light beam emitted by a single light source into a first light beam and a second light beam respectively on the first surface and the second light beam of the object to be measured by the light splitting element. The focusing position of the first surface and the second surface is obtained by focusing on the surface, and then the optical information of the object to be measured is calculated from the focusing position information. In this way, in this embodiment, the measurement system only uses a single light source to perform fast optical measurement on the opposite sides of the object to be measured to confirm its optical properties, and the structure of the measurement system can be simplified and the cost thereof can be reduced. In addition, it can solve the problem that the traditional measurement method needs to destroy the object to be measured for measurement.

Although the present invention has been disclosed above by the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the scope of the appended patent application.

10‧‧‧Object to be tested 100‧‧‧Measurement system 110‧‧‧Light source 120, 130‧‧‧Spectroscopic element 140, 150‧‧‧Sensing element 160‧‧‧Mobile platform 170_1, 170_2, 170_3, 170_4‧‧ ‧Objective lenses 180_1, 180_2‧‧‧Light guide device C1, C2‧‧‧Focal point L‧‧‧Light beam L1‧‧‧First beam L2‧‧‧Second beam R‧‧‧Spherical center S1‧‧‧First surface S2‧‧‧Second side S500, S510, S520, S530, S540, S550, S560, S570, S580‧‧‧Steps

FIG. 1 is a schematic diagram of a measurement system according to an embodiment of the present invention. FIG. 2 is a schematic diagram of measuring a test object according to an embodiment of the present invention. FIG. 3 is a schematic diagram of measuring a test object according to another embodiment of the present invention. FIG. 4 is a schematic diagram of measuring a test object according to another embodiment of the present invention. FIG. 5 is a flow chart of steps of a measurement method according to an embodiment of the present invention.

10‧‧‧Object to be tested

100‧‧‧Measuring System

110‧‧‧Light source

120, 130‧‧‧spectroscope

140, 150‧‧‧Sensing element

160‧‧‧Mobile Platform

170_1, 170_2, 170_3, 170_4‧‧‧objectives

180_1, 180_2‧‧‧Light guide device

L‧‧‧beam

L1‧‧‧First beam

L2‧‧‧Second beam

S1‧‧‧First side

S2‧‧‧Second side

Claims (12)

A measuring system, suitable for measuring an object to be measured, the measuring system comprises: a light source; a first light splitting element, arranged downstream of the light path of the light source; a light guide device, arranged on the first light path of the first light splitting element downstream; a second light splitting element, located downstream of the first optical path of the light guide device; a first sensing element, located downstream of the second optical path of the first light splitting element; a second sensing element, located in the the downstream of the first optical path of the second light splitting element; and a moving platform disposed between the first light splitting element and the second light splitting element. The measurement system of claim 1, wherein the object to be measured is disposed on the moving platform to move between the first spectroscopic element and the second spectroscopic element. The measurement system according to claim 1, wherein the first beam splitting element and the second beam splitting element are beam splitters with transmittances ranging from 40% to 60%. The measurement system as described in item 1 of the claimed scope further comprises: a temperature control module, adjacent to the object to be measured, for changing the temperature of the object to be measured. A measuring method suitable for an object to be measured, the measuring method comprising: providing a first beam and a second beam of a measuring system to a first surface and a second surface opposite to the object to be measured; detecting the the first beam and the second beam reflected by the object to be tested to obtain two first focus coordinates of the first surface and the second surface; and A shape thickness of the object to be measured is calculated according to the two first focus coordinates. The measurement method as described in claim 5, wherein the measurement method further comprises one of the following steps: (1) the first light beam and a second light beam are respectively formed by a single light source through a light splitting element, (2) ) correcting the optical axis of the object to be measured and the measurement system by means of a standard jig or image discrimination correction, (3) the method for obtaining the two first focus coordinates also includes: moving the object to be measured to make the first beam Focus and move the object to be tested on the first surface to focus the second beam on the second surface, and record the position of the first surface and the position of the second surface as the two first focus coordinates, (4) The method for calculating the shape thickness of the object to be tested includes: calculating the shape thickness according to the difference between the thickness of a reference object and the two first focus coordinates. The measurement method according to item 5 of the scope of the application, further comprising: providing the first beam and moving the object to be measured so that the focus of the first beam is transferred from the first surface of the object to be measured to the object to be measured the second surface of the test object; detect the first light beam reflected by the test object to obtain two second focus coordinates of the first surface and the second surface; and calculate according to the two second focus coordinates A material thickness of the object to be tested. The measuring method according to claim 7, wherein the method for calculating the thickness of the material of the object to be measured according to the two first focusing coordinates comprises: according to the thickness of a reference object and the two second focusing coordinates to calculate the thickness of the material. The measurement method as described in claim 8, wherein the measurement system further comprises a focusing element, and the measurement method further comprises: providing the first light beam and moving the object to be tested so that the spherical center of the focusing element coincides with the spherical center of the first surface; and detecting the first light beam reflected by the object to be tested to obtain the first surface a radius of curvature. The measuring method as described in item 9 of the scope of the application, wherein the measuring method further comprises: obtaining a Refractive index value. The measuring method according to claim 10, further comprising: replacing the light source to provide a third beam and moving the object to be measured so that the focus of the third beam is separated from the first surface of the object to be measured transferring to the second surface of the test object; detecting the first light beam reflected by the test object to obtain two third focus coordinates of the first surface and the second surface; and according to the two second The focusing coordinates and the two third focusing coordinates calculate an Abbe value of the object to be tested, wherein the wavelengths of the first beam and the third beam are different. The measurement method according to claim 11, wherein the measurement system further comprises a temperature control module, and the measurement method further comprises: measuring the object to be measured at different temperatures; and measuring according to different temperatures As a result, a refractive index change value of the test object at different temperatures is obtained.

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