TWI540308B - Optical detection system and interference controlling method thereof - Google Patents

Description

Optical detection system and interference control method thereof

The present invention relates to an optical detection system and an interference control method thereof.

With advances in technology, optical detection systems are widely used in a variety of measuring instruments and electronic devices, such as atomic force microscopy (AFM), optical microscopy (OM), microelectromechanical systems (MEMS), microstructure measuring instruments or resonant frequencies. A measuring instrument or the like for detecting a rough state or a very small displacement of an object surface, and an electronic device for reading a storage medium, such as a CD player, a DVD player, or a Blu-ray disc player.

Taking the structure of the astigmatic optical detection system as an example, it includes an objective lens, a beam splitting component, a light source system, and a photo-sensing system. When the detection light emitted by a light source system reaches the object to be tested, it may penetrate the object to be tested, and the transmitted light is reflected back to the optical path system by the actual object to be tested or the surface of the environment under the object to be tested. These stray light (reflected light) is not the light required by the photo-sensing system to obtain the actual surface information of the object to be tested, but may cause light interference with the detected light reflected by the object to be tested, which may cause errors in the measurement results.

Therefore, how to provide an optical detection system and its interference control method can avoid the measurement error caused by optical interference, thereby improving the reliability and accuracy of the optical detection system, and has become one of the important topics.

In view of the above problems, an object of the present invention is to provide an optical detection system and an interference control method thereof, which can reduce measurement errors caused by optical interference, thereby improving the reliability and accuracy of the optical detection system.

In order to achieve the above object, an optical detection system according to the present invention is configured to detect a test object, and the optical detection system includes a light source module, a light splitting component, an objective lens, and a photo-sensing module. A shading element. The light source module emits a detection light. Spectroscopic component Shooting to detect light. The objective lens refracts the detected light reflected by the spectroscopic element to the object to be tested. The photo-sensing module receives one of the reflected light generated by the reflection of the object to be detected. The shading element is disposed between the objective lens and the object to be tested, and the shading element shields at least part of the light reflected by the ambient surface.

In an embodiment, the shading element comprises a light shielding layer.

In an embodiment, the shading element is a light shielding sheet.

In one embodiment, the shape of the shading element is circular, semi-circular, polygonal, elliptical or irregular.

In an embodiment, the light shielding layer or the light blocking member has an opening.

In one embodiment, the diameter of the opening is less than or equal to the penetration diameter of the objective lens.

In an embodiment, the shading element may include a substrate, wherein the light shielding layer is disposed on the substrate.

In one embodiment, the object to be tested includes a probe unit having a cantilever and a probe, the probe is coupled to the cantilever, and the light shielding member is disposed between the objective lens and the probe.

In view of the above problems, an interference control method for an optical detection system according to the present invention includes: providing an optical detection system including an objective lens, a beam splitting component, a light source module, and a photo-electricity sensing module And a shielding element is disposed between the objective lens and an object to be tested to shield a portion of the light reflected by an environmental surface.

According to the optical detection system and the interference control method of the present invention, by providing a light shielding element between the objective lens and the object to be tested, the light emitted by the light source module can be refracted to the object to be tested through the objective lens. At least part of the light penetrates the object to be tested and is shielded by the light-shielding element after being reflected by the lower surface of the environment, thereby reducing the intensity of the light reflected by the ambient surface received by the photo-sensing module, thereby reducing the interference of light and the interference of light. The error that results in the measurement results can further improve the reliability and accuracy of the optical detection system.

1, 1a‧‧‧ optical detection system

11‧‧‧Light source module

12‧‧‧ Objective lens

14, 14a‧‧‧ shading elements

141‧‧‧ openings

142‧‧‧Lighting layer

143‧‧‧Substrate

15‧‧‧Spectral components

16‧‧‧Light Inductance Module

2‧‧‧Environmental surface

3, 3a‧‧‧ test object

31‧‧‧ probe

32‧‧‧ cantilever

B‧‧‧ actual test object

F‧‧‧stray light

N‧‧‧ needle seat

S01, S02‧‧‧ steps

1 is a schematic diagram of an optical detection system in accordance with a preferred embodiment of the present invention.

2 is a schematic diagram of an optical detection system according to another preferred embodiment of the present invention.

Figure 3 is a bottom view of the optical detection system.

4 is a flow chart of an interference control method of an optical detection system according to a preferred embodiment of the present invention.

Hereinafter, an optical detecting system and an interference control method thereof according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals. It should be noted that the figures are only for the sake of illustration. They do not represent the actual size and proportion. The application can have different designs and changes.

Please refer to FIG. 1 , which is a schematic diagram of an optical detection system according to a preferred embodiment of the present invention. The optical detection system 1 can be used to detect the intensity of light reflected by an object to be tested 3. Using the detected light intensity, the optical detection system 1 can determine the vertical displacement of the object 3 (relative to the main The light path), or the surface height or roughness of the object to be tested 3, and the precision is up to the nanometer level. For example, the optical detection system 1 can be applied to an optical microscope, an X-ray microscope, an atomic force microscope, or a device for reading a storage medium, etc., wherein the device for reading the storage medium can be, for example, a CD player, which includes a CD player, DVD player or Blu-ray disc player, etc. When the optical detection system 1 is used as a read head of an optical microscope, an X-ray microscope or an atomic force microscope, the object to be tested 3 may include a probe unit; when the optical detection system 1 is used as a reading storage medium When the head of the device is read, the object to be tested 3 may be, for example, a disc.

As shown in FIG. 1 , the optical detection system 1 of the present embodiment is applied to a device for reading a storage medium. The optical detection system 1 includes a light source module 11 , an objective lens 12 , a light splitting component 15 , and a photoelectric device . The sensing module 16 and a shading element 14 are provided. The object to be tested 3 is an optical storage element, such as an optical disc. Here, the aspect of the optical detection system is not limited.

In practice, the light source module 11 can be, for example, one or more laser diodes or include other light-emitting elements required for other systems, such as light-emitting diodes, halogen lamps, tungsten filament bulbs, and the like. . The light source module 11 is configured to emit a detecting light (for example, a red laser) to a beam splitting element 15 , and the detecting light is reflected by the beam splitting element 15 to the objective lens 12 .

In this case, the light splitting element 15 can reflect or refract incident light according to the incident angle of the light. In other words, in the embodiment, the light splitting component 15 can partially detect the light emitted by the light source module 11. The light is reflected to the objective lens 12, and the light splitting element 15 can also refract a reflected light generated by the object 3 to detect the light to the photo-sensing module 16.

The objective lens 12 is, for example, a convex lens for collecting the detection light so that the detection light is refracted through the objective lens 12 to be refracted to the object to be tested 3. Here, the focal length of the objective lens 12 and the distance from the spectroscopic element 15 may vary depending on actual needs, and the present invention is not limited thereto.

The light shielding member 14 is disposed between the objective lens 12 and the object to be tested 3. In the implementation, the light shielding layer 14 can include a light shielding layer 142 and a substrate 143. For example, the light shielding layer 14 is combined with the light shielding layer 142 and the substrate 143. The substrate 143 is a transparent substrate, and the light shielding layer 142 is disposed on the substrate 143. One side is provided on the substrate 143, for example, by printing or spraying. In practice, the thickness of the substrate 143 may be, for example, 0.1 mm to 0.6 mm. More specifically, when the optical detection system 1 is applied to a CD player, the thickness of the substrate 143 can be 0.6 mm; when the optical detection system 1 is applied to a Blu-ray disc player, the thickness of the substrate 143 can be 0.1 mm. It should be noted that the thickness of the above substrate 143 is only an example. In different embodiments, the thickness of the substrate 143 may be changed according to actual needs. In addition, in different embodiments, the substrate 143 can be removed according to different measurement applications, and the invention is not limited thereto.

The light shielding element 14 can be disposed in connection with the objective lens 12 or otherwise disposed between the objective lens 12 and the object to be tested 3, which is not limited by the present invention. In this embodiment, the shape of the light shielding member 14 is circular, but not limited thereto (in different embodiments, the shape of the light shielding member may also be semicircular, polygonal, elliptical or irregular, etc.) And the shading element 14 has an opening 141 for allowing the detection of light to pass. Preferably, the diameter of the opening 141 can be smaller than the penetration diameter (diameter) of the objective lens 12. Here, the diameter of the opening 141 can be 2 mm to 3 mm, or in other embodiments, the diameter of the opening 141 can be The present invention is not limited by the difference in the diameter of the aperture of the objective lens 12.

The photo-sensing module 16 is configured to receive a reflected light reflected by the object to be tested 3 and convert it into a voltage signal, thereby obtaining information about the surface or the displacement of the object 3 to be measured. Here, the photo-sensing module 16 is exemplified by a four-quadrant photodiode IC (PDIC). When the detection light is incident on the surface of the object to be tested 3, the reflected light reflected by the object to be tested 3 is received by the photo-sensing module 16 and converted into a voltage value, and after being calculated, the object to be tested 3 can be stored. Information on the information.

Since the thickness of the object to be tested 3 is very thin, or the area of the detection light hitting the object to be tested 3 is larger than the area of the object to be tested 3, part of the detected light passes through the object to be tested 3 or from the object to be tested 3 The surrounding area leaks to other places and then hits an environmental surface 2, where the environmental surface 2 is, for example, The tray of the CD player or the sample stage on which the sample is placed. The purpose of the shading element 14 is to shield at least part of the light (which may be referred to as stray light F) reflected by the ambient surface 2, thereby reducing the stray light F from being incident on the photo-sensing module 16. The intensity, so that the photo-sensing module 16 can reduce the influence of the interference of the light when acquiring the information of the object to be tested 3, thereby improving the accuracy and reliability.

Please refer to FIG. 2, which is a schematic diagram of another optical detection system in accordance with a preferred embodiment of the present invention. The optical detection system 1a is the same as the optical detection system 1 except that the optical detection system 1a of the present embodiment is applied to an astigmatic atomic force microscope. Here, the object to be tested 3a includes A probe unit.

The probe unit includes a probe 31 and a cantilever 32, wherein the probe 31 is coupled below the cantilever 32, and the probe unit is located at the focus of the objective lens 12. In general, the probe 31 has a tip size of only a few nanometers, and the cantilever 32 has a width of 45 to 55 microns and a thickness of 200 to 500 nm. Here, the detection light is exemplified by a red laser having a focal point diameter of about 560 nm, and the detection light is focused on the cantilever 32 by the refraction of the objective lens 12, more precisely, focusing on the probe. The extension of the needle tip of the 31 is perpendicular to the intersection of the cantilever 32 toward a surface of the objective lens 12.

It should be noted that, in this embodiment, the probe unit is defined as the object to be tested 3a, which is used to describe the detection of the focus detection of the light. In practical applications, the probe 31 of the probe unit is abutted. On an actual object B. When the relative position of the actual object B and the probe 31 of the probe unit is changed, the probe unit will be displaced in the vertical direction due to the fluctuation of the actual object B, resulting in different intensity of the reflected detection light. The photo-sensing module 16 receives the reflected light of different degrees of reflection to determine the surface contour of the actual object B.

Since the thickness of the probe unit (the object to be tested 3a) and the actual object to be tested B may be thin, or the irradiation area of the detection light to the probe unit and the actual object B is larger than the probe unit and the actual to be tested When the area of the object B is partially detected, the light is transmitted through the object to be tested 3a or leaked to the other side of the object to be tested 3a, and then hits an environmental surface 2 (Fig. 2 is used to detect light penetration). The needle unit and the actual object B are taken as an example. For example, the environmental surface 2 is, for example, a stage of an atomic force microscope. Here, the shading element 14a is located between the objective lens 12 and the cantilever 32. The light shielding member 14a can be a light shielding sheet, and the material thereof can be, for example, a material including iron sheets, opaque or light absorbing materials, or a material that is opaque or light absorbing on a plastic sheet, as long as it can block the environment. table The light reflected from the surface 2 can be used, and the invention is not limited.

In this way, part of the light (stray light F) reflected by the environmental surface 2 can be shielded by the light shielding element 14a, and the intensity of the stray light F being incident on the photo-sensing module 16 can be reduced, thereby making the optical inductance measurement. When acquiring the displacement information of the probe unit, the module 16 reduces the influence of the interference of the light, so that the accuracy and reliability can be improved.

Please refer to FIG. 3, which is a bottom view of the optical detection system. Here, the optical detection system 1a applied to the atomic force microscope is taken as an example, so please refer to FIG. 2 at the same time for the understanding. The light shielding element 14a is disposed between the objective lens 12 and the probe 31, and the main surface of the light shielding element 14a is substantially perpendicular to the optical path of the optical detection system 1a, so that the reflected light of the shielding portion can pass. As can be seen in FIG. 3, the cantilever 32 held by the needle holder N is disposed in the opening 141 to detect the reflected light of the light reflected by the surface of the environmental surface 2, except from the original light path. The opening 141 of the shading element 14a is reflected back to the photo-sensing module 16 , and other light rays can be substantially blocked by the shading element 14 a without being sensed by the photo-sensing module 16 . The blocked light is not the necessary light required for the photo-sensing module 16 to sense the displacement information of the probe unit. Instead, the blocked reflected light is reflected to the photoelectricity if not blocked by the light-shielding element 14a. The sensing module 16 will cause optical interference, resulting in measurement errors, which in turn affect the detection results. In other words, by providing the light shielding element 14a between the objective lens 12 and the probe unit, the generation of light interference can be reduced, and the reliability and accuracy of the optical detection system 1a can be improved. It should be noted that the light blocked by the light shielding element 14a can reduce the interference light reflected by the environmental surface 2, that is, the light shielding element 14a can also be a filter layer, which can reduce unnecessary band influence. Sensing of the photo-sensing module 16.

Please refer to FIG. 4, which is a flowchart of an interference control method of an optical detection system according to a preferred embodiment of the present invention. The interference control method of the optical detection system includes step S01 and step S02.

In step S01, an optical detection system is provided. The optical detection system includes an objective lens, a beam splitting component, a light source module, and a photo-sensing module. In step S02, a shading element is disposed between the objective lens and an object to be tested to shield at least part of the light reflected by an environmental surface. The technical features of this embodiment are the same as those of the foregoing embodiment, so please refer to the foregoing description, and details are not described herein again.

In summary, an optical detection system and interference control thereof according to the present invention In the method, by providing a light-shielding element between the objective lens and the object to be tested, the light emitted by the light source module can be incident on the surface of the object to be tested through the objective lens, and some of the light penetrates the object to be tested and is reflected by the lower surface of the environment. The shading element is shielded to reduce the intensity of the light received by the photo-sensing module, thereby avoiding the interference of the light and the interference caused by the optical interference, thereby improving the reliability of the optical detection system. Degree and precision.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1‧‧‧ Optical detection system

11‧‧‧Light source module

12‧‧‧ Objective lens

14‧‧‧ shading elements

141‧‧‧ openings

142‧‧‧Lighting layer

143‧‧‧Substrate

15‧‧‧Spectral components

16‧‧‧Light Inductance Module

2‧‧‧Environmental surface

3‧‧‧Test object

F‧‧‧stray light

Claims (14)

An optical detection system for detecting an object to be tested, the optical detection system comprising: a light source module for emitting a detection light; a light splitting component for reflecting the detected light; and an objective lens, Refraction of the detected light reflected by the spectroscopic element to the object to be tested; a photo-sensing module receiving a reflected light generated by the object to be detected to reflect the detected light; and a shading element disposed on the object Between the objective lens and the object to be tested, and the light shielding element shields at least part of the light reflected by the detection light through an environmental surface, wherein the environmental surface is a platform surface disposed on the object to be tested, wherein the object to be tested The utility model comprises a probe unit having a probe and a cantilever, the probe is connected to the cantilever, and the probe unit is located at a focus of the objective lens, and the detection light is focused by the refraction of the objective lens a surface of the cantilever, and the light shielding element is disposed between the objective lens and the probe. When detecting, the probe of the probe unit is topped against an actual object to be tested, when the actual test is to be performed. The relative position of the object and the probe When the probe unit will depend on the actual undulating was measured while displacement in the vertical direction. The optical detection system of claim 1, wherein the shading element comprises a light shielding layer. The optical detection system of claim 1, wherein the shading element is a light shielding sheet. The optical detection system of claim 1, wherein the shading element has a shape of a circle, a semicircle, a polygon, an ellipse or an irregular shape. The optical detection system of claim 1, wherein the shading element has an opening. The optical detection system of claim 5, wherein the diameter of the opening is less than or equal to the penetration diameter of the objective lens. The optical detection system of claim 2, wherein the shading element further comprises a substrate, wherein the light shielding layer is disposed on the substrate. An interference detection method for an optical detection system includes: providing an optical detection system, the optical detection system comprising a light source module, a light splitting component, an objective lens, and a photo-sensing module; and providing a light-shielding component Between the objective lens and an object to be tested, to shield at least part of the light reflected by an environmental surface, wherein the environmental surface is a platform surface disposed on the object to be tested, wherein the object to be tested comprises a probe unit having a probe and a cantilever, the probe is connected to the cantilever, and the probe unit is located at a focus of the objective lens, and the detection light is focused on a surface of the cantilever by refraction of the objective lens, and the The light shielding component is disposed between the objective lens and the probe. When detecting, the probe of the probe unit is abutted against an actual object to be tested, and the relative position of the actual object to be tested is opposite to the probe. When changing, the probe unit will generate a vertical displacement according to the fluctuation of the actual object to be tested. The interference control method of the optical detection system of claim 8, wherein the shading element comprises a light shielding layer. The interference control method of the optical detection system of claim 8, wherein the shading element is a light shielding sheet. The interference control method of the optical detection system of claim 8, wherein the shading element has a shape of a circle, a semicircle, a polygon, an ellipse or an irregular shape. The interference control method of the optical detection system of claim 8, wherein the shading element has an opening. The interference control method of the optical detection system of claim 12, wherein the diameter of the opening is less than or equal to the penetration diameter of the objective lens. The interference control method of the optical detection system of claim 9, wherein the shading element further comprises a substrate, wherein the light shielding layer is disposed on the substrate.