JP2017037041A - Measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device, which is a system for irradiating an object with irradiation light through a telecentric optical system having two lenses and a diaphragm arranged between the lenses and receiving reflected light from the object, that suppresses missing of receiving light output distribution while achieving miniaturization, compared to the case without considering a position of a semi-transmissive mirror.SOLUTION: A measuring device includes: a light-emitting section which emits irradiation light; a first lens which changes a degree of divergence of the irradiation light; a diaphragm section which narrows the irradiation light; a second lens which condenses the irradiation light having passed through the diaphragm section and irradiates an object with the condensed light from a direction parallel to an optical axis; a first light-receiving section which receives a part of reflected light after the irradiation light has irradiated the object, reflected, and passed through the second lens; a semi-transmissive mirror which makes the irradiation light emitted from the first lens pass toward the diaphragm section and reflects the reflected light having passed through the diaphragm section; a second light-receiving section which receives the reflected light reflected by the semi-transmissive mirror; and a measuring section which measures the object using a light-receiving result of the first light-receiving section and a light-receiving result of the second light-receiving section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measuring device.

  In Patent Document 1, a light source and a light beam emitted from the light source are measured light beams having a cross-sectional shape in which a ring-shaped defect portion is formed in a part of the ring-shaped pattern in the circumferential direction in a cross section perpendicular to the optical axis. A light beam shaping unit that can be shaped into a shape, a light blocking position changing unit that changes the formation position of the annular zone defect part, a first condensing optical system that condenses the measurement light beam on the measurement surface of the sample to be measured, and measurement A second condensing optical system for condensing a reflected light beam reflected by the sample to be measured among the light beams, and a positional relationship optically conjugate with the surface to be measured across the second condensing optical system The second condensing on the image plane optically conjugate with the surface to be measured by the aperture stop disposed at the aperture stop, the photometry unit for measuring the light beam that has passed through the aperture stop, and the second condensing optical system. A photometric device is disclosed that includes an observation unit capable of observing a projection image by an optical system. In the photometric device disclosed in Patent Literature 1, the light shielding member is moved in order to change the formation position of the defect portion in the measure against the defect portion of the light beam to be measured.

  Patent Document 2 discloses a receiving system for forming an image of a target surface with at least one conjugate plane, and an aperture stop surface of the receiving system or at least one pupil plane of the receiving system that is a conjugate plane with the receiving system. In the instrument provided, at least one beam manipulation unit EMS, which is controlled in an elementally independent manner, is arranged in a plane conjugate to the object plane and at least one EMS in the pupil plane, in which case EMS Disclosed is an instrument characterized in that each is coupled with an information technology system ITS that controls the elements of the EMS to manipulate the properties of the radiation so that different beam paths can be produced through programming, each via an interface ing. In the instrument disclosed in Patent Document 2, adjustment is made by moving the irradiated beam as a countermeasure for the missing portion of the light beam to be measured.

JP 2014-092366 A JP-T-2004-522488

  An object of the present invention is to provide a measurement apparatus that irradiates an object with irradiation light through a telecentric optical system having a diaphragm disposed between two lenses and the lens, and receives reflected light from the object. Compared to the case where the position of the semi-transparent mirror is not taken into consideration, the omission of the received light output distribution is suppressed while achieving miniaturization.

  In order to achieve the above object, a measuring device according to claim 1 is a first light emitting unit that emits irradiation light to be irradiated on an object, and a first degree of divergence of the irradiation light emitted from the light emitting unit. A lens, a diaphragm having an aperture for converging the irradiation light emitted from the first lens, and condensing the irradiation light passing through the opening and irradiating the object from a predetermined direction And at least a part of the reflected light that is disposed between the second lens, the diaphragm unit, and the second lens, and the irradiation light is reflected by being irradiated on the object and is transmitted through the second lens. A first light receiving portion that receives light, and is disposed between the first lens and the aperture portion, and transmits the irradiation light emitted from the first lens toward the aperture portion, and The reflected light that has passed through the opening is reflected. A semi-transparent mirror, a second light-receiving unit that receives the reflected light reflected by the semi-transparent mirror, and a light-receiving result of the first light-receiving unit and a light-receiving result of the second light-receiving unit. And a measuring unit that measures the object.

  According to a second aspect of the present invention, in the first aspect of the invention, the light emitting unit includes a plurality of light emitting elements arranged in a direction crossing the predetermined direction, The light receiving unit includes a plurality of first light receiving elements disposed in a plane intersecting the predetermined direction, and the second light receiving unit includes at least one second light receiving element, And a control unit for controlling the light emission timings of the light emitting elements and the light reception timings of the plurality of first light receiving elements and the second light receiving elements.

  According to a third aspect of the present invention, in the second aspect of the present invention, the control unit sequentially causes the plurality of light emitting elements to emit light, and each of the plurality of light emitting elements emits the plurality of second light emitting elements. One light receiving element and the second light receiving element are controlled to receive light.

  The invention according to claim 4 is the invention according to claim 2 or claim 3, wherein the semi-transmission mirror is parallel to an arrangement direction of the plurality of light emitting elements with respect to an irradiation direction of the irradiation light. It is arranged tilted around the axis.

  According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the distance between the light receiving surfaces of the plurality of first light receiving elements and the second lens is This is equal to the focal length of the second lens.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the semi-transmission mirror is provided between the semi-transmission mirror and the second light receiving unit. It further includes a third lens that condenses the reflected light reflected toward the second light receiving unit.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the measurement unit has a light reception result of the first light receiving unit and a predetermined coefficient. An output distribution including the multiplied light reception result of the second light receiving unit is generated, and the object is measured using the output distribution.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein a distance between the opening and the first lens is a focal length of the first lens. And the distance between the opening and the second lens is equal to the focal length of the second lens.

  An invention according to a ninth aspect is the invention according to any one of the first to eighth aspects, wherein the second light receiving part is disposed between the light emitting part and the second light receiving part. It further includes a light shielding member that shields the irradiation light so as not to enter the light receiving portion, and an antireflection member that is disposed on the light emitting portion side surface of the diaphragm portion and prevents the reflection of the irradiation light.

  According to the first aspect of the present invention, it is possible to obtain an effect that the omission of the received light output distribution is suppressed while achieving downsizing as compared with the case where the position of the semi-transmissive mirror is not considered.

  According to the second aspect of the present invention, the light emitting element is always allowed to emit light without being controlled by the control unit, and the irradiation light and the reflected light are easily separated as compared with the case where the light receiving element always receives light. The effect is obtained.

  According to the third aspect of the present invention, the output distribution from the light receiving unit can be obtained for each light emitting element as compared with the case where the light emitting elements emit light collectively.

  According to the fourth aspect of the present invention, the semi-transparent mirror is semi-symmetrical with respect to the irradiation direction of the irradiation light as compared with the case where the semi-transmission mirror is inclined with respect to an axis perpendicular to the arrangement direction of the plurality of light emitting elements. The effect that the range of the irradiation light from the light emitting part that transmits the transmission mirror or the range of the reflected light that is reflected by the semi-transmission mirror is enlarged is obtained.

  According to the fifth aspect of the present invention, the position of the object is compared with the case where the distance between the light receiving surface of the first light receiving element and the second lens is different from the focal length of the second lens. Even if the angle fluctuates up and down, left and right, the same output distribution can be obtained by irradiating different irradiation light on the same position of the object.

  According to the sixth aspect of the present invention, there is an effect that the second light receiving unit is downsized as compared with the case where the second light receiving unit directly receives the reflected light without the third lens. It is done.

  According to the seventh aspect of the invention, it is more accurate than the case of generating an output distribution including the light reception result of the second light receiving unit and the light reception result of the first light receiving unit without multiplying by a coefficient. The effect that the output distribution is acquired is obtained.

  According to the eighth aspect of the present invention, when the distance between the opening and the first lens is different from the focal length of the first lens, or the distance between the opening and the second lens is the first distance. As compared with the case where the length is different from the focal length of the second lens, an effect that a telecentric lens is configured is obtained.

  According to the ninth aspect of the present invention, a light receiving output distribution with higher accuracy can be obtained as compared with the case where there is no light blocking member that blocks the irradiation light or an antireflection member that prevents the reflection of the irradiation light. The effect that

It is a front view which shows an example of a structure of the measuring device which concerns on 1st Embodiment. It is a side view which shows an example of a structure of the measuring device which concerns on 1st Embodiment. It is a top view which shows an example of a structure of the light receiver which concerns on embodiment. It is a block diagram which shows an example of a structure of the control part which concerns on embodiment. It is a time chart for demonstrating control of the light emitter and light receiver which concern on embodiment. It is a figure for demonstrating the measuring method of the light reception output distribution of the measuring device which concerns on 1st Embodiment, and the defect | deletion in light reception output distribution. It is a figure which shows the structure of the measuring device which concerns on a comparative example. It is a figure for demonstrating operation | movement of the measuring device which concerns on 1st Embodiment. It is a front view which shows an example of a structure of the measuring device which concerns on 2nd Embodiment.

[First Embodiment]
The present embodiment will be described in detail with reference to FIGS. First, with reference to FIG.1 and FIG.2, an example of a structure of the measuring device 10 which concerns on this Embodiment is demonstrated.

  As shown in FIG. 1, the measuring apparatus 10 includes a light emitter 14, an optical system 30, a light receiver 18, a condensing optical system 70, and a control unit 20. The measurement apparatus 10 sequentially irradiates light on the fine region of the object OB moving in the −X direction from the Z-axis direction, and acquires the reflection angle distribution of each reflected light (the reflection angle dependency of the light amount distribution). Using the acquired reflection angle distribution, the distance from the object OB and the change in the angle of the object OB with respect to the shape change and surface state of the object OB (such as wrinkles, embossing, surface roughness, surface defects, foreign matter adhesion, etc.) Measurements are made without being affected by

  More specifically, as shown in FIG. 1, the light emitter 14 is arranged above the apparatus vertical direction (Z-axis direction) with respect to the measurement region T through which the object OB moving in the −X direction passes. Yes. The light emitter 14 includes a plurality of light emitting elements 12 mounted side by side in the Y-axis direction on the substrate 14A and having the −Z direction as the light emission direction. In other words, the plurality of light emitting elements 12 are arranged in a direction orthogonal (crossing) to the moving direction (−X direction) of the object OB. In FIG. 1, the light emitting element 12 disposed at one end (right end in the drawing) of the substrate 14A is referred to as a light emitting element 12A, and the other end (left end in the drawing) of the substrate 14A in the Y axis direction. The arranged light emitting element 12 is denoted as a light emitting element 12B, and the light emitting element 12 disposed in the center of the substrate 14A is denoted as a light emitting element 12C.

  The plurality of light emitting elements 12 according to the present embodiment are configured to emit light sequentially from the light emitting element 12A to the light emitting element 12B with a time difference, and the light from each light emitting element 12 is at a different position on the object OB. Irradiated sequentially. Then, while the object OB moves in the −X direction in the measurement region T, one cycle of light emission from the light emitting element 12A to the light emitting element 12B is repeated a plurality of times. 2 shows the light beam of the irradiation light IF emitted from the light emitting element 12C, and FIG. 1 shows the reflected light RF in which the irradiation light IF is reflected by the surface 200 of the object OB.

  Although it does not specifically limit as the light emitting element 12, As an example, a surface emitting laser (Vertical Cavity Surface Emitting Laser: VCSEL), a light emitting diode (Light Emitting Diode: LED), etc. are used.

  The optical system 30 includes a lens 32, a lens 34, and a diaphragm 40 disposed between the lens 32 and the lens 34, and is configured as a so-called double-sided telecentric lens. The optical system 30 is disposed between the light emitter 14 and the object OB, guides the irradiation light emitted from the light emitting element 12 to the object OB, and reflects the reflected light reflected by the object OB to the light receiver 18. Lead. In the present embodiment, the optical axis of the lens 32 and the optical axis of the lens 34 are a common optical axis M, and this optical axis M is the center of the light emitting element 12C of the light emitter 14 and an opening 42 described later. It passes through the center.

  The lens 32 is, for example, a circular convex lens in plan view, and the diameter J (see FIG. 2) of the lens 32 is based on the dimension D (see FIG. 1) in the Y-axis direction from the light emitting element 12A to the light emitting element 12B. Have been long. Therefore, almost all of the light emitted from each light-emitting element 12 is transmitted through the lens 32, and the light transmitted through the lens 32 is changed in the degree of divergence and becomes parallel light and travels toward the lens 34.

  The lens 34 is, for example, a circular convex lens in plan view. In the present embodiment, the diameter G of the lens 34 is longer than the diameter J of the lens 32. The lens 34 condenses the light beam emitted from the lens 32 and transmitted through the lens 34 toward the surface 200 of the object OB. Note that the position (focal point) of the condensing point of the lens 34 is not necessarily the position of the surface 200 of the object OB. The position of the condensing point may be shifted (defocused) from the position of the surface 200, and the irradiation diameter of the irradiation light IF on the surface 200, that is, the size of the irradiation region of the object OB may be adjusted. In addition, the irradiation diameter which concerns on this Embodiment is several tens of micrometers as an example.

  A substantially circular opening 42 is formed in the stop 40, and the light beam emitted from the light emitting element 12, passing through the lens 32 and entering the lens 34 is stopped by the opening 42. More specifically, the diaphragm 40 has a plate shape whose plate surface is parallel to the XY plane, and the diaphragm 40 has a tip that is bent and tapered toward the lens 34 around the optical axis M. The part is formed. This tip portion is an opening edge 42A constituting the opening 42, and the circular shape formed by the opening 42 has the optical axis M as the central axis. In addition, the diameter of the opening part 42 which concerns on this Embodiment is about 1 mm as an example.

  In the Z-axis direction, the distance F1 between the opening edge 42A and the lens 32 is substantially equal to the focal length f1 of the lens 32, and the distance F2 between the opening edge 42A and the lens 34 is equal to the focal distance f2 of the lens 34. It is almost equal.

  The optical system 30 according to the present embodiment configured as described above narrows the light flux from each light emitting element 12 that is sequentially emitted regardless of the position of the light emitting element 12 and is parallel to the optical axis M. The object OB is irradiated as an appropriate irradiation light IF (see FIG. 6). In other words, by scanning each light emitting element 12 to emit light, light beams having substantially circular cross sections that are narrowed and parallel to each other are sequentially irradiated onto the object OB. Furthermore, in the measuring apparatus 10 according to the present embodiment, the irradiation area of the irradiation light IF on the target object OB is substantially the same by arranging the target object OB in the vicinity of the condensing point of the light beam of the irradiation light IF by the lens 34. It is a fine area. As a result, in the measuring apparatus 10, even if the position of the object OB fluctuates up and down in the Z-axis direction, each irradiation light is irradiated with substantially the same irradiation diameter, so that the blur of the image of the object OB is extremely reduced. The

  The light receiver 18 includes a plurality of light receiving elements 16 and receives the reflected light RF reflected by the object OB and transmitted through the lens 34 of the optical system 30. As shown in FIGS. 1 and 2, the light receiver 18 according to the present embodiment is disposed on the lower side in the Z-axis direction of the diaphragm 40 disposed between the lens 32 and the lens 34. Although there is no restriction | limiting in particular as the light receiving element 16, For example, a photodiode (Photodiode: PD), a charge-coupled device (Charge-Coupled Device: CCD) etc. are used.

  Since the light receiver 18 is disposed between the lens 32 and the lens 34, the light receiving element 16 is similarly disposed between the lens 32 and the lens 34. Here, the fact that the light receiving element 16 is disposed between the lens 32 and the lens 34 means that the outer diameter end of the lens 34 (virtual contact point between the front surface R (radius) and the rear surface R), as shown in FIG. It means that the light receiving element 16 is disposed on the inner side with respect to the cylindrical surface formed by the line P extending in the Z-axis direction.

  FIG. 3A shows an example of the configuration of the light receiver 18. FIG. 3A is a plan view of the light receiver 18 as viewed from the Z-axis direction. The photoreceiver 18 shown in FIG. 1 is a cross-sectional view cut along X-X ′ in FIG. As shown in FIG. 3A, for example, the light receiver 18 has a plurality of light receiving elements 16 (in FIG. 3A) on a substantially circular substrate 18A having a substantially circular opening 18B in the center. 60 examples are shown) arranged in a planar shape (array shape). In the measuring apparatus 10, the reflected light RF is received by using the entirety of the plurality of light receiving elements 16 as the light receiving region RA. FIG. 3A illustrates the light receiver 18 having a configuration in which a plurality of light receiving elements 16 are arranged on the entire surface of the substrate 18A. However, the present invention is not limited to this, and depending on the light receiving range of the reflected light RF and the like. It is good also as the light receiver 18 of the form which has arrange | positioned the light receiving element 16 in a part of board | substrate 18A.

The range of the reflected light RF received by the light receiving region RA is, for example, the reflected light RF having an angle of 0 ° to 40 ° with an axis parallel to the optical axis M as the center. When the reflected light RF is received by the light receiving area RA, a three-dimensional distribution is formed by the amount of light received by each light receiving element 16. When the reflected light RF is isotropic as in the case where it is reflected on the completely diffusing surface, the shape of the cross section of this three-dimensional distribution cut along the plane including the Z axis is shown in FIG. As shown, it is a substantially Gaussian curve.
In addition, the light receiving element numbers 1 to 6 on the horizontal axis in FIG. 3B are the numbers 1 to 6 of the light receiving elements 16 illustrated in FIG. Further, since the reflected light RF is not received between the light receiving element 16 and the light receiving element 16 in the light receiving region RA, the actual output distribution is discrete, but this is omitted in FIG. Yes.

  Furthermore, in the measuring apparatus 10, the light receiving surface of the light receiving element 16 and the opening edge 42 </ b> A are at the same position in the Z-axis direction, so the distance F <b> 2 between the light receiving surface of the light receiving element 16 and the lens 34 is the focal point of the lens 34. The length is the same as the distance f2. For this reason, even if the position of the object OB fluctuates up and down in the Z-axis direction or fluctuates left and right in the Y-axis direction, and irradiation light IF from different light emitting elements is irradiated, As long as the irradiation position is the same, the output distribution in the light receiving region RA is always constant.

  In other words, assuming that the target object OB is a very small region having an irradiation diameter, when the target object OB moves up and down in the Z-axis direction or left and right in the Y-axis direction, different light emitting elements 12 are used. In the measurement apparatus 10 according to the present embodiment, the output distribution of the entire light receiving element 16 included in the light receiving region RA is reflected light RF. The output distribution is always the same regardless of the occurrence position.

  As shown in FIG. 4, the control unit 20 includes a CPU (Central Processing Unit) 100, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 104. The CPU 100 controls and controls the entire measurement apparatus 10. The ROM 102 is a storage unit that stores in advance a control program of the measurement apparatus 10. The RAM 104 is used as a work area at the time of execution of a program such as the control program. Storage means. The CPU 100, the ROM 102, and the RAM 104 are connected to each other by a bus BUS.

  The bus BUS is connected to a light emitter 14, a light receiver 18, and a light receiving element 54 described later, and each of the light emitter 14, the light receiver 18, and the light receiving element 54 controls the CPU 100 via the bus BUS. receive.

With reference to FIG. 5, the control of the light emitter 14, the light receiver 18, and the light receiving element 54 by the control unit 20 will be described. FIG. 5A shows a light emission pulse signal P1 for causing a certain light emitting element 12 to emit light when the light emitting element 12 of the light emitter 14 is caused to emit light sequentially as described above, and FIG. 5B shows the next light emission. A light emission pulse signal P2 for causing the element 12 to emit light is shown.
As shown in FIGS. 5A and 5B, in the control of the light emitter 14 according to the present embodiment, no signal (for a predetermined period) between the light emission pulse signal P <b> 1 and the light emission pulse signal P <b> 2 ( 0 level) time is provided (portions corresponding to times t2 and t4 in FIG. 5). FIG. 5C shows the reflected light RF generated by the irradiation light IF generated from the light emitting element 12 by the light emission pulse signals P1 and P2, and the light receiver 18 and the light receiving element 54 (hereinafter, all of the light receiving elements 16 included in the light receiver 18). And the light receiving element 54 are collectively referred to as “all light receiving elements”). With this reading pulse, the amount of light received by all the light receiving elements is read and used as a signal indicating the output distribution.

  First, the reflected light RF of the irradiation light IF generated by the light emission pulse signal P1 is read by all the light receiving elements at time t1. Now, assuming that the number of all light receiving elements is k, k light receiving signals Sr (1), Sr (2),..., Sr (k) are obtained from each light receiving element. Next, at time t2, the received light amount of 0 level between the light emission pulse signal P1 and the light emission pulse signal P2 is read by all the light receiving elements. Let k received light signals read by all the light receiving elements be Sr0 (1), Sr0 (2),..., Sr0 (k). Next, the difference between the light reception signal of the reflected light RF of all the light receiving elements and the light reception signal of 0 level, that is, Sr (1) −Sr0 (1), Sr (2) −Sr0 (2),. (K) −Sr0 (k) is calculated, and the k difference values are used as the output distribution of the amount of received light. The output distribution is calculated in the same manner for the light emission pulse signal P2 and thereafter. In the present embodiment, the light reception signal of the light receiving element 54 is multiplied by a correction coefficient and combined with the light reception signal of the light receiving element 16, and details of this correction will be described later.

  As described above, the signal indicating the output distribution by the reflected light RF is generated by subtracting the non-signal received signal from the received signal of the reflected light RF in order to eliminate the influence of the ambient light. When the influence of the above can be ignored, the light reception signal of the reflected light RF may be used as a signal indicating the output distribution as it is. Further, in this case, there is no need to make a gap between successive light emission pulse signals, and furthermore, since the timing of light reception is determined by the read pulse, some of them may overlap.

On the other hand, the condensing optical system 70 includes a half mirror 50, a lens 52, and a light receiving element 54, and has a function of condensing the reflected light RF transmitted through the opening 42 of the diaphragm 40.
With reference to FIG. 6, the operation of the measurement apparatus 10 and the function of the condensing optical system 70 when measuring the reflection characteristic (for example, the degree of unevenness of the surface) of the object OB will be described in more detail. 6A to 6C show the irradiation light IF light flux and the irradiation light IF when the light emitting elements 12A, 12C, and 12B of the light emitter 14 sequentially emit light without the condensing optical system 70. FIG. The light beams of the reflected light RF reflected by the surface 200 of the object OB and guided to the light receiver 18 are shown.

  First, when the object OB moves in the −X direction and the tip of the object OB enters the measurement region T, each light emitting element 12 sequentially emits light with a time difference, and the irradiation light IF is directed toward the object OB. Irradiated sequentially. Then, light emission of one cycle from the light emitting element 12A to the light emitting element 12B is repeated until the rear end of the object OB passes through the measurement region T. As described above, the light emission control of the light emitting element 12 is executed by the control unit 20.

  The degree of divergence of the light beam of the irradiation light IF emitted from each light emitting element 12 is changed by the lens 32 so as to face the direction of the lens 34. The luminous flux whose divergence degree has been changed by the lens 32 is narrowed (limited) by the diaphragm 40. The light beam focused by the diaphragm 40 is collected by the lens 34 and irradiated onto the object OB from the Z-axis direction. In other words, the object OB is disposed in the vicinity of the condensing point of the irradiation light IF by the lens 34. As described above, the irradiation light according to the present embodiment is collected on the surface 200 of the object OB to about several tens of μmφ as an example.

  The irradiation light IF irradiated to the object OB is reflected by the surface 200 of the object OB, and generates reflected light RF (indicated by a dotted line with an arrow in FIG. 6). The direction of the light beam of the reflected light RF is changed by the lens 34 so as to be directed toward each light receiving element 16. The reflected light RF transmitted through the lens 34 is received by each light receiving element 16.

  Depending on the state of the surface 200 of the object OB, the irradiation light IF is reflected in various directions. In the present embodiment, as described above, the light passing through the incident point of the IF on the surface 200 of the irradiation light. The reflected light RF in an angle range of 0 ° to 40 ° is received around an axis parallel to the axis M. Therefore, the light receiving area RA of the light receiver 18 corresponding to the irradiation light IF emitted from one light emitting element 12 is substantially circular. An example of the light receiving region RA in FIG. 3A is shown.

  The light reception signal received by each light receiving element 16 is read at a predetermined timing under the control of the control unit 20 as described above. The read light reception signal may be temporarily stored in a storage unit such as a RAM. The control unit 20 generates an output distribution (light reception profile) for each light receiving region RA using a light reception signal (luminance signal) corresponding to each light emitting element 12. Since the output distribution includes angle information of the reflected light RF, for example, the degree of unevenness of the object OB is measured.

  Here, as described above, the light receiver 18 according to the present embodiment has the opening 18B corresponding to the opening 42 of the diaphragm 40 at the center of the substrate 18A. The reflected light RFd, which is a part of the reflected light RF, that is, the reflected light RFd composed of the reflected light with respect to the irradiation light IF parallel to the optical axis M and the reflected light in a certain range around the reflected light RFd, It will pass through the opening 42. Accordingly, the output distribution of the light receiver 18 is deficient due to the reflected light RFd, and this deficiency often occurs near the top of the output distribution (for example, Gaussian distribution). Therefore, it is desirable to take some measures for receiving the reflected light RFd.

  A measurement apparatus 90 shown in FIG. 7 is a measurement apparatus according to a comparative example that is configured not to generate the output distribution defect due to the reflected light RFd. The measuring device 90 will be described with reference to FIG. FIG. 7 shows the irradiation light IF emitted from the light emitting element 12C and the reflected light RF in which the irradiation light IF is reflected by the surface 200 of the object OB.

  As shown in FIG. 7, the measuring device 90 includes the light emitter 14, an optical system 60 including a lens 32, a lens 34, and a diaphragm 92, a half mirror 94, and a light receiver 98. Yes. The measuring device 90 includes a half mirror 94 instead of the condensing optical system 70 of the measuring device 10, and the light receiver 18 is changed to a light receiver 98.

  Similar to the measuring apparatus 10, the irradiation light IF sequentially emitted by the light emitter 14 is reflected by the surface 200 of the object OB, and generates reflected light RF. At this time, the irradiation light IF passes through the lens 32, the half mirror 94, and the lens 34 and reaches the surface 200 of the object OB.

  On the other hand, the reflected light RF is reflected by the half mirror 94 as shown in FIG. 7, and is guided to a light receiver 98 having a plurality of light receiving elements 96 arranged in a plane parallel to the ZX plane. The distance (optical path length) between the light receiving surface of each light receiving element 96 and the lens 34 is equal to the focal length of the lens 34. The light receiver 98 outputs a light reception signal of the reflected light RF received by the plurality of light receiving elements 96 as a signal indicating an output distribution. According to the measuring device 90, the reflected light RF has its optical path changed before reaching the opening 42 and is guided to each light receiving element 96, so that the occurrence of defects in the output distribution is suppressed.

  However, since the half mirror 94 of the measuring device 90 reflects almost the entire reflected light RF directed toward all the light receiving elements 96, the shape needs to be increased. When the shape of the half mirror 94 is increased, the distance between the diaphragm 92 and the lens 34 is increased, the focal length of the lens 34 is also increased, and the size of the entire measuring apparatus is increased. The amount of light received by the light receiver 98 is also halved when the light emitted from the light emitting element 12 is transmitted through the half mirror 94, and is halved when the reflected light RF is reflected by the half mirror 94. Therefore, it attenuates to 1/4 as a result. For this reason, the light receiving sensitivity of the light receiver 98 is deteriorated as compared with the case where countermeasures against defects in the output distribution are not taken.

  Therefore, in the present invention, the condensing optical system 70 is employed to suppress the occurrence of defects in the output distribution.

With reference to FIG.1 and FIG.2 again, the condensing optical system 70 which concerns on this Embodiment is demonstrated.
As shown in FIGS. 1 and 2, the condensing optical system 70 includes a half mirror 50, a lens 52, and a light receiving element 54. As shown in FIG. 2, the irradiation light IF emitted from each light emitting element 12 passes through the half mirror 50 and reaches the surface 200 of the object OB. The reflected light RF is reflected by the surface 200, most of the light is received by the light receiving element 16 as shown in FIG. 1, and a part of the reflected light RF passes through the opening 42 as reflected light RFd. As shown in FIG. 2, the reflected light RFd that has passed through the opening 42 is reflected by the half mirror 50, passes through the lens 52, and then is received by the light receiving element 54.

  Here, the light receiving element 54 may be the same as the light receiving element 16 or may be another type of light receiving element having different light receiving sensitivity or the like. For example, if a light receiving element 54 having a light receiving sensitivity twice that of the light receiving element 16 is used, correction in the light output of the light receiving element 16 and the light receiving element 54 due to the transmittance and reflectance of the half mirror 50 described later is performed. You don't have to do it.

  The operation of the condensing optical system 70 will be described in more detail with reference to FIG. FIG. 8B is a diagram showing a necessary part of the front view shown in FIG. 1, and FIG. 8A is a plan view seen from the direction D of FIG. 8B.

As shown in FIG. 8B, when the irradiation light IF is sequentially emitted from the light emitting element 12A (see FIG. 1) to the light emitting element 12B in the light emitter 14, the reflected light with respect to each irradiation light IF is reflected light RFa ( From reflected light RFb (only the reflected light parallel to the optical axis M is shown) to the reflected light RFb are sequentially generated in the direction indicated by the white arrow S in the figure. The reflected light from the reflected light RFa to RFb (that is, a part of the reflected light RF) passes through the opening 42 as reflected light RFd and is reflected by the half mirror 50. The reflected light RFd according to the present embodiment is, for example, light in a range of 0 ° to 5 ° (cross-sectional area in a plane parallel to the XY plane of the light beam) about an axis parallel to the optical axis M. . As described above, the reflected light RF according to the present embodiment is light in the range of 0 ° to 40 ° centering on an axis parallel to the optical axis M, and therefore the range of the reflected light RFd is the range of the reflected light RF. It is approximately 1/100 of the range (≈ (tan (5 °) / tan (40 °)) ² ).

  As shown in FIG. 8A, the reflected light RFd reflected by the half mirror 50 is condensed by the lens 52 and received by the light receiving element 54 sequentially from the reflected light RFa to RFb in the direction of the white arrow S. That is, when light is emitted sequentially from the light emitting elements 12A to 12B, a part of the reflected light RF is received by the light receiving element 16 of the light receiver 18, and is received by the light receiving element 16 by the light receiving element 54 of the condensing optical system 70. Another part that complements the reflected light RF is received. The light reception signal received by the light receiving element 16 and the light reception signal received by the light receiving element 54 may each be temporarily stored in a storage unit such as the RAM 104.

  The CPU 100 of the control unit 20 synthesizes these light reception signals to generate an output distribution having no defect as shown in FIG. 3B (however, as described above, the light receiving element 16 and the light receiving element 16 in the light receiving region RA). The reflected light RF is not received between the light receiving element 16 and the actual output distribution is discrete). Note that, as will be described later, the amount of reflected light received by the light receiving element 54 is ½ of the amount of reflected light received by the light receiving element 16. It is necessary to synthesize the received light signal value by doubling it. However, this factor of 2 is further corrected if necessary according to the transmittance and reflectance of the half mirror 50.

  As described above, according to the measuring apparatus 10 according to the present embodiment, the half mirror 50 transmits the irradiation light IF from the light emitting elements 12 arranged in one direction and only reflects a part of the reflected light RF. Since the size is sufficient, the outer shape can be small. As a result, the measuring device 10 is reduced in size.

  In addition, the reflected light RFd received by the light receiving element 54 has a light quantity of 1 as the light from the light emitting element 12 passes through the half mirror 50 and is reflected by the half mirror 50, as in the measurement device 90 according to the comparative example. / 4. However, most of the reflected light RF is received by the light receiving element 16, and the reflected light RF received by the light receiving element 16 is halved by the light from the light emitting element 12 passing through the half mirror 50. Light. Therefore, compared with the measuring device 90 according to the comparative example, the deterioration of the light receiving sensitivity in the light receiver 18 is also suppressed. In the above description, it is assumed that the transmittance and the reflectance of the half mirror 50 are 50%, respectively. However, when the transmittance and the reflectance are not 50%, the light receiving element 16 and The amount of light received by the light receiving element 54 is different from the above. In this case, the correction value for the amount of light received by the light receiving element 54 may be changed from twice according to the actual transmittance and reflectance values.

  Here, in the above embodiment, the lens 52 is described as an example of a substantially circular convex lens. However, the present invention is not limited to this. As shown in FIG. 8A, the lens 52 only has to collect the RFb from the reflected light RFa scanned in the S direction (−Y direction). A lens having a narrow axial width may be used. Furthermore, it may be a kamaboko type cylindrical lens which does not have a light collecting function in the Z-axis direction. If the light receiving region of the light receiving element 54 can receive a light beam in the range from the reflected light RFa to the reflected light RFb, the lens 52 may not be provided.

  Moreover, in the said embodiment, as shown in FIG. 1, although the form which made the width | variety of the half mirror 50 substantially equal to the diameter of the light receiver 18 was illustrated, it is not restricted to this. By setting the width of the half mirror 50 to a larger one of the width that allows the irradiation light IF sequentially irradiated from the light emitting element 12 to be transmitted and the width that allows the reflected light RFd to be reflected, The condensing optical system 70 is further reduced in size.

[Second Embodiment]
With reference to FIG. 9, a measurement apparatus 10A according to the present embodiment will be described.

  As shown in FIG. 9, the measuring apparatus 10 </ b> A is only provided with a light shielding member 80 and antireflection members 82 </ b> A and 82 </ b> B (collectively, “antireflection member 82”) around the condensing optical system 70. However, it is different from the measurement apparatus 10 described above. As is apparent with reference to FIG. 9, if the light shielding member 80 is not provided, the irradiation light IF irradiated from the light emitting element 12 becomes stray light and interferes with the reflected light RFd passing through the opening 42 or receives light. There is a possibility of direct incidence on the element 54. Without the antireflection member 82, the reflected light reflected by the diaphragm 40 or the like becomes stray light, which may interfere with the reflected light RFd or may directly enter the light receiving element 54. When such light crosstalk occurs, the irradiation light IF becomes noise, the amount of light received by the light receiving element 54 of the reflected light RFd fluctuates, and a correct output distribution cannot be obtained.

  Therefore, in the present embodiment, a light blocking member 80 that blocks the irradiation light IF is provided above the condensing optical system 70, and the reflection prevention of the reflection of the irradiation light IF is prevented on the surface of the diaphragm 40 on the light emitter 14 side. A member 82A is provided, and similarly, an antireflection member 82B is provided around the aperture 40. For example, the light shielding member 80 and the antireflection member 82 may be provided by attaching a tape subjected to a light shielding treatment and an antireflection treatment, respectively. As a result, the influence of disturbance light in the light reception of the light receiving element 54 is suppressed, so that an output distribution with improved accuracy can be obtained.

  In each of the above embodiments, the optical axis of the condensing optical system 70 (the optical axis of the light beam from the half mirror 50 toward the light receiving element 54) is orthogonal to the direction in which the light emitting elements 12 of the light emitter 14 are arranged (crossing). However, the present invention is not limited to this, and the embodiment is not limited to this. For example, the condensing optical system 70 shown in FIG. 1 and FIG. It is good also as a form rotated 90 degrees as the center.

  In each of the above-described embodiments, an example in which one light receiving element 54 of the condensing optical system 70 is disposed has been described. However, the present invention is not limited to this, and a plurality of light receiving elements 54 are disposed according to the size of the received light beam. It is good also as a form to do.

  In each of the above-described embodiments, the light emitters 14 have been described by exemplifying the form in which the light emitting elements 12 are arranged in one row in one direction. However, the present invention is not limited thereto, and a plurality of rows may be arranged. At that time, the emission wavelength of the light emitting element 12 may be varied for each column. For example, the wavelength dependency of the reflected light on the surface 200 of the object OB is measured by causing the light emitting elements 12 to emit light with different emission wavelengths for each column.

  In each of the above-described embodiments, the lens 32, the lens 34, and the lens 52 have been illustrated and described as substantially circular convex lenses. However, the present invention is not limited to this, and other forms of lenses, such as aspherical lenses, etc. May be used. Further, in each lens, an unnecessary portion where the light beam is not transmitted may be deleted. Thereby, the measuring apparatus 10 is further reduced in size.

10, 10A Measuring device 12, 12A, 12B, 12C Light emitting element 14 Light emitter 14A Substrate 16 Light receiving element 18 Light receiver 18A Substrate 18B Aperture 20 Control unit 30 Optical system 32 Lens 34 Lens 40 Aperture 42 Aperture 42A Aperture edge 50 Half Mirror 52 Lens 54 Light receiving element 60 Optical system 70 Condensing optical system 80 Light blocking member 82, 82A, 82B Antireflection member 90 Measuring device 92 Aperture 94 Half mirror 96 Light receiving element 98 Light receiver 100 CPU
102 ROM
104 RAM
200 Surface BUS Bus IF Irradiation light M Optical axis OB Object P1 to P4 Light emission pulse signal RA Light reception area RF, RFa, RFb, RFd Reflected light T Measurement area

Claims (9)

A light emitting unit that emits irradiation light to irradiate the object;
A first lens that changes a divergence degree of the irradiation light emitted from the light emitting unit;
A diaphragm having an opening for narrowing the irradiation light emitted from the first lens;
A second lens that collects the irradiation light that has passed through the opening and irradiates the object from a predetermined direction;
A first light receiving element that is disposed between the aperture section and the second lens and receives at least a part of the reflected light that is reflected when the irradiation light is irradiated onto the object and is transmitted through the second lens. And
It is disposed between the first lens and the diaphragm, and transmits the irradiation light emitted from the first lens toward the diaphragm and reflects the reflected light that has passed through the opening. A semi-transparent mirror,
A second light receiving unit that receives the reflected light reflected by the semi-transmissive mirror;
A measurement unit that measures the object using a light reception result of the first light receiving unit and a light reception result of the second light receiving unit;
Measuring device including The light emitting unit includes a plurality of light emitting elements arranged in a direction intersecting with the predetermined direction,
The first light receiving unit includes a plurality of first light receiving elements arranged in a plane intersecting the predetermined direction,
The second light receiving unit includes at least one second light receiving element,
The measuring apparatus according to claim 1, further comprising a control unit that controls light emission timings of the plurality of light emitting elements and light reception timings of the plurality of first light receiving elements and the second light receiving elements. The control unit causes the plurality of light emitting elements to sequentially emit light, and controls the plurality of first light receiving elements and the second light receiving elements to receive light for each light emission of the plurality of light emitting elements. 2. The measuring device according to 2. The measuring apparatus according to claim 2, wherein the semi-transmissive mirror is disposed to be inclined with respect to an irradiation direction of the irradiation light with an axis parallel to an arrangement direction of the plurality of light emitting elements as a center. The measuring apparatus according to claim 2, wherein a distance between the light receiving surfaces of the plurality of first light receiving elements and the second lens is equal to a focal length of the second lens. . 2. A third lens for condensing the reflected light reflected by the semi-transmissive mirror toward the second light-receiving unit between the semi-transmissive mirror and the second light-receiving unit. The measuring device according to claim 5. The measurement unit generates an output distribution including a light reception result of the first light receiving unit and a light reception result of the second light receiving unit multiplied by a predetermined coefficient, and uses the output distribution to generate the output distribution. The measuring device according to any one of claims 1 to 6, which measures an object. The distance between the opening and the first lens is made equal to the focal length of the first lens, and the distance between the opening and the second lens is made equal to the focal length of the second lens. The measuring device according to any one of claims 1 to 7. A light-shielding member that is disposed between the light-emitting unit and the second light-receiving unit and shields the irradiation light so as not to enter the second light-receiving unit;
The measurement apparatus according to claim 1, further comprising: an antireflection member that is disposed on a surface of the diaphragm unit on the light emitting unit side and prevents reflection of the irradiation light.