JP2011033436A - Tilt sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt sensor which can measure each tilt angle of a regular reflection surface and an irregular reflection surface simultaneously by one sensor. <P>SOLUTION: The tilt sensor includes an optical system constituted of a light projection part for emitting measuring light toward a detection domain, and a light reception part for receiving the measuring light reflected by the detection domain. The light projection part has a constitution including a light emitting element and a collimator lens, and the light reception part includes a regularly reflected light measuring part and an irregularly reflected light measuring part. The regularly reflected light measuring part includes a light receiving lens and a light receiving element, and the irregularly reflected light measuring part has a constitution including a light receiving lens, a light receiving element, an irregularly reflected light receiving mirror, and a regularly reflected light-irregularly reflected light composite half mirror. One light receiving lens is used in common for the light receiving lens in the regularly reflected light measuring part and the light receiving lens in the irregularly reflected light measuring part, and one light receiving element is used in common for the light receiving element in the regularly reflected light measuring part and the light receiving element in the irregularly reflected light measuring part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tilt sensor, and more particularly to a tilt sensor capable of simultaneously measuring the tilt angles of a regular reflection surface and a diffuse reflection surface such as diffracted light with one sensor.

  Conventionally, tilt sensors (tilt sensors) that measure the tilt amount of an inspection object are known. However, these conventional tilt sensors can measure only one of the inclination angle of the regular reflection surface or the inclination angle of the irregular reflection surface. For this reason, there has been a problem that it is not easy to obtain a reference for measuring the inclination angle of the irregular reflection surface.

  Therefore, for example, as shown in Patent Document 1, in order to measure the reflected light of a regular reflection surface that is zero-order light and the reflected light of a diffuse reflection surface such as diffracted light that is n-order light, A photodetector that receives diffracted light from the element and outputs a photoelectric conversion signal is further provided, and further includes difference signal generation means for further receiving zero-order light and generating a difference signal from the photoelectric conversion signal of zero-order light. Thus, there has been proposed an inclination sensor that can measure the reflected light of the regular reflection surface and the reflected light of the irregular reflection surface with one sensor. However, even with such an inclination sensor, it is difficult to instantaneously determine the inclination angle of the regular reflection surface and the irregular reflection surface, and further, a difference signal generation means is further provided separately from the photodetector, There was a problem that the apparatus was enlarged.

JP 2004-279191 A

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a tilt sensor capable of simultaneously measuring the inclination angles of the regular reflection surface and the irregular reflection surface with one sensor. There is.

  The above object of the present invention includes an optical system including a light projecting unit that emits measurement light toward the detection region and a light receiving unit that receives the measurement light reflected from the detection region, A light emitting element and a collimator lens, wherein the light receiving unit includes a regular reflection light measurement unit and a diffuse reflection light measurement unit, and the regular reflection light measurement unit includes a light reception lens and a light receiving element. The irregularly reflected light measuring unit includes a light receiving lens, a light receiving element, a diffusely reflected light receiving mirror, and a half mirror, and the light receiving lens of the regular reflected light measuring unit and the light receiving of the irregularly reflected light measuring unit. By providing a tilt sensor in which a lens is used as one light receiving lens, and the light receiving element of the specular reflection light measuring unit and the light receiving element of the irregular reflection light measuring unit are used as one light receiving element. Achieved.

  In addition, the above object of the present invention can be effectively achieved by providing a tilt sensor characterized in that the light receiving portion includes a light shielding plate.

  According to the tilt sensor of the present invention, the light receiving lens of the specular reflection light measurement unit of the light receiving unit and the light reception lens of the irregular reflection light measurement unit are combined with one light receiving lens, and the light receiving element and the irregular reflection of the specular reflection light measurement unit. Since the light receiving element of the light measuring unit is also used as one light receiving element, the tilt angle of the regular reflection surface and the irregular reflection surface can be simultaneously measured with one sensor.

It is a figure which shows the structure of the optical system of the tilt sensor which concerns on one Example of this invention. It is a block diagram for demonstrating the principle which measures the inclination amount of the regular reflection light of the tilt sensor shown in FIG. It is a block diagram for demonstrating the principle which measures the inclination amount of the irregularly reflected light of the tilt sensor shown in FIG.

  Hereinafter, a tilt sensor according to the present invention will be described in detail with reference to the drawings. It should be noted that the tilt sensor according to the present invention is not limited to the following embodiments, and it goes without saying that the configuration can be changed as appropriate without departing from the scope of the claims.

  FIG. 1 is a diagram showing a configuration of an optical system of a tilt sensor 1 (hereinafter referred to as “the present tilt sensor 1”) according to an embodiment of the present invention, in which a tilt amount of a specular reflection surface of a detection object, In addition, the tilt amount of the irregular reflection surface such as diffracted light is simultaneously measured by one sensor. That is, the tilt sensor 1 includes an optical system including a light projecting unit 2 that emits measurement light toward the detection region, and a light receiving unit 3 that receives the measurement light reflected from the detection region.

  The light projecting unit 2 includes a light projecting element 21 such as a light emitting diode (LED) and a light projecting lens 22 such as a collimator lens, and aligns the optical axes 23 of the light projecting element 21 and the light projecting lens 22 with each other. Configured. The light emitted from the light projecting element 21 is collimated by the light projecting lens 22 and irradiated to the detection object as measurement light 24 that is parallel light.

  In addition, as the light projecting element 21, laser light can be used in addition to the LED. Examples of such a laser beam projecting element 21 include a laser oscillator such as a helium-neon (He-Ne) laser and a semiconductor laser element (LD), or an optical fiber that guides laser light output from the laser oscillator. A pipe or the like can be used.

  The light receiving unit 3 receives the measurement light 24 and detects the amount of tilt that is the tilt angle of the specular reflection surface of the detection object, and the tilt angle of the irregular reflection surface such as diffracted light of the detection object. And an irregular reflection light measuring unit 32 for detecting a certain amount of tilt.

  As described above, the regular reflection light measurement unit 31 is an optical system that detects the amount of inclination of the regular reflection surface of the detection object, and includes the light receiving lens 33 and the light receiving element 34. As the light receiving element 34, various elements that can measure the position of a position detection element (PSD), a charge coupled device (CCD), or the like can be used.

  The irregular reflection light measuring unit 32 is an optical system that detects the amount of inclination of the irregular reflection surface such as the diffracted light of the detection object as described above, and the irregular reflection light receiving mirror 35, the light receiving lens 36, the light receiving element 37, and the half mirror 38. It comprises by comprising.

  The light receiving lens 33 of the regular reflection light measurement unit 31 and the light reception lens 36 of the irregular reflection light measurement unit 32 are also used as one light reception lens, and the light receiving element 34 and the irregular reflection light measurement unit 31 of the regular reflection light measurement unit 31. The light receiving element 37 is also used as one light receiving element. In this way, the light receiving lens 33 (36) and the light receiving element 34 (37) of the specular reflection light measurement unit 31 and the irregular reflection light measurement unit 32 are used in common, that is, the specular reflection light and the irregular reflection light are used. By receiving light with one light receiving element 34 (37), the inclination angle of the regular reflection surface and the inclination angle of the irregular reflection surface can be measured with one sensor.

  The light projecting unit 2 and the light receiving unit 3 are arranged symmetrically on both sides of the standard line SL, and the optical axis 23 of the light projecting unit 2 and the optical axis 39 of the light receiving unit 3 are both standard lines SL. Are equal to θ. Further, the optical axis 23 of the light projecting unit 2 and the optical axis 39 of the light receiving unit 3 intersect at one point of the standard line SL, and a point on the standard line SL at which the optical axes 23 and 39 intersect is determined. It is called a standard point SP, and a plane that passes through the standard point SP and is perpendicular to the standard line SL is defined as a test surface (regular reflection surface) SF1.

  Further, on the regular reflection surface SF1, the distance between the light projecting element 21 and the light projecting lens 22 is adjusted so that the optical axis 23 of the light projecting element 21 and the light projecting lens 22 is focused on the standard point SP. The optical unit 2 is configured. Further, the measurement light 24 that is the collimated light reflected at the standard point SP is condensed by the light receiving lens 33 of the regular reflection light measuring unit 31 (light receiving unit 3) and condensed on the light receiving element 34. The optical system of the regular reflection light measurement unit 31 is configured by adjusting the distance between the light receiving lens 33 of the reflected light measurement unit 31 and the light receiving element 34.

  Thereby, as shown by a solid line in FIG. 1, when the detection object is located on the regular reflection surface SF1 (that is, when the tilt amount β = 0), the measurement light emitted from the light projecting element 21 is obtained. When 24 is irradiated on the surface of the detection object, the optical axis 23 of the measurement light 24 is reflected by the standard point SP, that is, the measurement light 24 is specularly reflected by the surface of the detection object, and the reflected measurement light 24 is reflected. Passes through the light receiving lens 33 and forms an image on the light receiving element 34 to form a light receiving spot P 1 at a point on the optical axis 39. Hereinafter, the position of the light receiving spot P <b> 1 generated when the tilt amount β = 0 is also referred to as the origin position of the light receiving unit 3.

  Further, when the diffuse reflection angle of the irregularly reflected test surface (diffuse reflective surface) SF2 that is a plane perpendicular to the standard line SL (that is, the inclination β ′ = 0) is α, it is at a position θ−α from the standard line SL. The irregularly reflected light receiving mirror 35 is installed, and the measurement light 40 reflected by the irregularly reflected light receiving mirror 35 passes through the light receiving lens 36 via the half mirror 38 and forms an image at the position of the light receiving spot P1 on the light receiving element 37. As described above, the irregular reflection light receiving mirror 35 and the half mirror 38 are adjusted, and the optical system of the irregular reflection light measurement unit 32 is configured.

  Further, the light receiving unit 3 of the tilt sensor 1 is preferably provided with a light shielding plate 41. By providing the light shielding plate 41 in this way, the measurement of the specular reflection light and the irregular reflection light can be switched and only one of the regular reflection light or the irregular reflection light can be passed. Will be able to. That is, as shown in FIG. 1, when the light shielding plate 41 is provided in the optical system of the regular reflection light measurement unit 31 (provided between the standard point SP and the half mirror 38), the measurement light from the regular reflection light measurement unit 31 is supplied. Since it can interrupt | block, a diffusely reflected light can be measured independently. On the other hand, although not shown, if the light shielding plate 41 is provided in the optical system of the irregular reflection light measurement unit 32 (provided between the standard point SP and the irregular reflection light receiving mirror 35), the measurement light of the irregular reflection light measurement unit 32 is blocked. Therefore, specular reflection light can be measured independently.

  Next, as shown by a detection object SF1 ′ in FIG. 1, when the detection object (regular reflection surface) SF1 is inclined by β with respect to the standard line SL, the tilt amount of the regular reflection surface SF1 is detected by the tilt sensor 1. The principle of measuring β will be described. For the sake of simplicity, only the optical system of the regular reflection light measuring unit 31 that measures and detects the tilt amount β is extracted from the tilt sensor 1 and shown in FIG. 2 (note that the light shielding plate 41 is omitted). .)

As shown in FIG. 2, the measurement light 24 emitted from the light projecting element 21 passes through the light projecting lens 22 and becomes collimated light, and is irradiated onto the surface of the detection object SF1 ′. At this time, when the regular reflection surface SF1 which is the detection surface is inclined by β with respect to the standard line SL to be the detection surface SF1 ′ (when β ≠ 0), it is indicated by a broken line in FIGS. As described above, the measurement light 42 reflected by the surface of the detection surface SF1 ′ is inclined by θ + 2β with respect to the optical axis 39, so that the measurement light 42 reflected by the detection surface SF1 ′ passes on the light receiving element 34 through the light receiving lens 33. The formation position of the light reception spot P2 (hereinafter referred to as “light reception spot P2 for specular reflection light measurement”) generated by focusing is moved from the origin position P1 of the light reception spot. The amount of movement of the regular reflected light measurement light receiving spot P2 from the origin position (the distance from the origin position to the point P2, which is the center of gravity position of the received light intensity) is defined as a movement amount D. By detecting the movement amount D, the inclination amount β of the detection surface SF1 ′ can be calculated. That is, when the focal length (distance between the standard point SP and the light receiving lens 33) is f ₁ and the amount of movement of the light receiving spot P2 from the light receiving spot P2 from the origin P1 is D, the standard line SL is used as a reference. An inclination amount β of the detection surface SF1 ′ is expressed by the following (Equation 1).
(Equation 1)
f ₁ · 2β = D
β = D / 2f ₁

  Next, as shown by the detection object SF2 ′ in FIG. 1, when the detection object (diffuse reflection surface) SF2 for detecting the irregular reflection light when the irregular reflection angle is α is inclined by β ′ with respect to the standard line SL. The principle of measuring the tilt amount β ′ of the irregular reflection surface SF2 ′ of the detected object by the tilt sensor will be described. For ease of understanding, only the optical system of the irregularly reflected light measuring unit that measures and detects the tilt amount β ′ is taken out from the tilt sensor and shown in FIG. 3 (the light shielding plate 41 is omitted).

As shown in FIG. 3, the measurement light 24 emitted from the light projecting element 21 passes through the light projecting lens 22 and becomes collimated light, and is irradiated onto the surface of the detection object SF2 ′. At this time, when the detection surface SF2 is inclined by β ′ with respect to the standard line SL to become the detection surface SF2 ′ (when β ′ ≠ 0), the measurement light reflected on the surface of the detection surface SF2 ′ 43 also tilts with respect to the optical axis 39, so that the measurement light 43 reflected by the detection surface SF2 ′ is reflected by the irregularly reflected light receiving mirror 35 and then halfway as shown by a two-dot chain line in FIGS. The light is reflected by the mirror 38, passes through the light receiving lens 36, is collected on the light receiving element 37, and is referred to as a light receiving spot P <b> 3 (hereinafter, “light receiving spot for irregularly reflected light measurement” 3). ). At this time, the formation position of the light reception spot P3 for irregular reflection light measurement moves from the origin position P1 of the light reception spot. The amount of movement of the irregularly reflected light measurement light receiving spot P3 from the origin position P1 (the distance from the origin position to the point P3 that is the center of gravity of the received light intensity) is D ′. By detecting the movement amount D ′, the inclination amount β ′ of the detection surface SF2 ′ can be calculated. That is, when the focal length (distance between the standard point SP and the light receiving lens) is f ₁ and the amount of movement of the light receiving spot P3 for irregularly reflected light measurement from the origin position P1 is D ′, detection based on the standard line SL is performed. The inclination amount β ′ of the surface SF2 ′ is expressed by the following (Equation 2).
(Equation 2)
f ₁ · 2β ′ = D ′
β ′ = D ′ / 2f ₁

  Accordingly, the inclination angle β ′ of the irregular reflection surface SF2 can also be obtained as in the case of the regular reflection surface SF1 ′.

As described above, according to the tilt sensor 1, the light receiving lens 33 (36) and the light receiving element 34 (37) of the specular reflection light measuring unit 31 and the irregular reflection light measuring unit 32 are combined, and one light receiving element 34 (37). Since the measurement is performed, the inclination amounts β and β ′ of the regular reflection surface SF1 and the irregular reflection surface SF2 can be simultaneously measured with one sensor.

DESCRIPTION OF SYMBOLS 1 Tilt sensor 2 Light projection part 21 Light projection element 22 Light projection lens 3 Light reception part 31 Regular reflection light measurement part 32 Diffuse reflection measurement part 33, 36 Light reception lens 34, 37 Light reception element 35 Diffuse reflection light reception mirror 38 Half mirror 41 Light-shielding plate SL Standard line SP Standard point

Claims (2)

An optical system including a light projecting unit that emits measurement light toward the detection region, and a light receiving unit that receives the measurement light reflected by the detection region,
The light projecting unit includes a light emitting element and a collimator lens,
The light receiving unit includes a regular reflection light measurement unit and a diffuse reflection light measurement unit,
The specular reflection light measurement unit includes a light receiving lens and a light receiving element,
The irregularly reflected light measuring unit includes a light receiving lens, a light receiving element, a diffusely reflected light receiving mirror, and a half mirror.
The light receiving lens of the specular reflection light measurement unit and the light reception lens of the irregular reflection light measurement unit are combined with one light reception lens, and the light reception element of the specular reflection light measurement unit and the light reception element of the irregular reflection light measurement unit are combined into one. A tilt sensor that is also used as a light receiving element.   The tilt sensor according to claim 1, wherein the light receiving unit includes a light shielding plate.

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