WO1997037264A1

WO1997037264A1 - Confocal optical apparatus

Info

Publication number: WO1997037264A1
Application number: PCT/JP1997/001095
Authority: WO
Inventors: Hideyuki Wakai; Hiroyuki Mizukami; Toru Suzuki; Masato Moriya
Original assignee: Komatsu Ltd.
Priority date: 1996-03-29
Filing date: 1997-03-28
Publication date: 1997-10-09
Also published as: JPH09264720A

Abstract

A confocal optical apparatus provided with a confocal optical system including relay lenses (7, 7a, 7b), a pinhole array (4) in which pinholes (4a) are linearly or two-dimensionally arranged, and a photodetector array (8), and adapted to measure the intensities of light beams reflected from an object and passing through the pinholes, via the relay lenses. A diffusion member (20) adapted to diffuse at random the reflected light which has passed through the pinholes, is disposed in the vicinity of the reflected light focal point, whereby the reflected light which has passed through the pinholes is directed to the photodetecting portion of the photodetector array uniformly with a constant probability.

Description

Description Confocal optical device Technical field

The present invention relates to a confocal optic used in a three-dimensional shape inspection apparatus for quickly inspecting a three-dimensional shape, for example, a shape of an object to be measured, such as a solder bump for IC mounting, whose approximate surface shape is known. It concerns equipment. Background art

This type of confocal optical device is configured as shown in FIG. The light from the light source 1 is reflected by the mirror 40, becomes parallel light via the magnifying lenses 2a and 2b, and enters the hologram 3 as reference light. The hologram 3 reproduces light equivalent to a point light source emitted from each pinhole position of the pinhole array 4 in which the pinholes are two-dimensionally arranged by diffracting the reference light.

This reconstructed light is projected onto an object (measurement object) 6 via the first objective lens 5a, is reflected and scattered by the object 6, and the reflected light is transmitted to the first object lens 5a, The light passes through the hologram 3 and is focused on the pinhole array 4 via the second objective lens 5b. Note that Fig. 1 represents the light at one pinhole position as a representative.

2, 3, and 4 show the relationship between the position of the condensing point of the first objective lens 5 a of the projected light with respect to the positional relationship in the optical axis direction (Z direction) of the surface of the object 6 in the confocal optical system. Depending on position, reflected light with pinhole array 4 It shows how to form an image nearby. According to this, as shown in Fig. 3, the reflected light passes through the pinhole 4a of the pinhole array 4 only when the focal point and the surface of the object 6 are coincident (focused). That is, as shown in FIG. 2, the focal point is located after the reflecting surface (surface) of the object 6 (rear pin), or as shown in FIG. 4, when located before the reflecting surface (front pin). In the meantime, the reflected light is shielded by the pinhole array 4 and can hardly pass therethrough, so that a so-called light receiving aperture function is performed.

By utilizing this characteristic, the amount of reflected light passing through the pinhole 4a while moving the object 6 in the optical axis direction (Z direction) can be reduced as shown in FIG. By measuring the light by making it incident on the two-dimensional photodetector array 8 via the ray lenses 7a and 7b, the position where the maximum amount of light is obtained is the surface of the object 6. That is, the position of the surface of the object 6 can be measured. This is called peak processing. FIG. 1 has the confocal optical system described with reference to FIGS. 2 to 4, in which the pinholes 4a are two-dimensionally arranged, so that while moving the object 6 in the Z direction, By measuring the amount of reflected light passing through 4a and subjecting it to peak processing, the surface shape of the object 6 corresponding to each pinhole 4a can be measured. In practice, the first and second objective lenses 5a and 5b are both constituted by a telecentric system (also referred to as an afocal system or a tandem arrangement optical system), and the object 6 is formed. Instead of moving in the Z direction, move the first objective lens 5a in the Z direction and measure.

The light passing through the pinhole 4a is coupled to a photodetector array 8 for detecting two-dimensional light via first and second relay lenses 7a and 7b. The light that passes through each pinhole 4a is imaged and measured on an independent photodetector. The control device 9 controls the XY position of the stage 10 on which the object 6 is placed (if necessary, the offset position in the Z direction), determines the measurement field of view, and determines the first objective lens. 5 a is moved in the Z direction, and the measured value of the photodetector array 8 is read out and peak-processed while detecting the position in the Z direction, and the result is displayed, output or recorded.

Next, the manufacturing process of the hologram 3 will be described with reference to FIG. The light source 11 is a coherent light source such as a laser, and the light emitted from the light source 11 is split into two lights by wavefront splitting by the beam splitter 12. These are the light sources for the reference light and object light of Hologram 3, respectively. When the light from the light source 11 exhibits the characteristic of linearly polarized light, the polarization direction of the linearly polarized light is rotated by rotating the first half-wave plate 13a, and the polarization beam splitter 12 By adopting a lid, the intensity ratio of the division is set to a desired value.

The reference light and the object light generated by the wavefront splitting by the beam splitter 12 are the first, second, third, and fourth enlarged lenses 14a, 14b, and 14c, Each of them is enlarged by 14 d and incident on the hologram 3 and the pinhole array 4 respectively. The light transmitted through the pinhole array 4 is diffracted by the respective pinholes 4a, becomes light equivalent to a point light source, is converted into parallel light by the objective lens 5b, and is converted into a parallel light by the objective lens 5b. Is incident on the object as object light. By adjusting the second and third half-wave plates 13b and 13c, the polarization directions of the reference light and the object light are set to desired directions (generally, the same direction as the same direction). The setting for hologram exposure is completed. Figures 6 to 8 show other conventional examples that do not use holograms. FIG. 6 shows the first conventional type shown in Japanese Patent Application Laid-Open No. Hei 4-26959, U.S. Pat.No. 5,239,178 _(from light source 1 to light source 1). The light is expanded by the magnifying lens 2 and is incident on the pinhole array 4. The light diffracted by each of the pinholes 4 a passes through the beam splitter 15, The first objective lenses 5b and 5a project light to the object 6.

Then, the light projected and reflected and scattered on the object 6 passes through the first and second objective lenses 5a and 5b in reverse, and enters the beam splitter 15 here. The light is reflected by the light detector and forms an image on the photodetector array 8. 'FIG. 7 shows a second prior art, shown in US Pat. No. 4,806,004. The light from the light source 1 is enlarged by the magnifying lens 2, passes through the half mirror 41, is incident on the pinhole array 4, and is diffracted by the pinhole 4 a, and the light diffracted by the pinhole 4 a The light is projected onto the object 6 by the objective lenses 5b and 5a. The light projected and reflected and scattered on the object 6 passes through the objective lenses 5a and 5b, and is condensed on the pinhole array 4 which functions as a light receiving aperture. Then, the light passing through each pinhole 4a is reflected by the half mirror 41, and forms an image on the photodetector array 8 on a one-to-one basis via the relay lens 7. In this configuration, the pinhole array 4 that creates a point light source for projection and the pinhole array 4 that defines the receiving aperture have the same structure.However, light must be incident from behind the pinhole array 4. The extra light such as the reflected light R from the pinhole mask 4 b of the pinhole array 4 is prevented from reaching the detector array 8 by any method. Note that, in the second conventional type, the pinhole 4a and the pixel of the detector array 8 do not have a one-to-one correspondence, and instead, the pinhole array 4 is scanned in the XY plane. Then, images of the pinholes 4a and 4a are obtained, and such a confocal optical system is referred to as a tandem-type scanning confocal optical system.

FIG. 8 shows a tandem scanning optical system of the same kind as the second conventional type described in Japanese Patent Application Laid-Open No. 1-503493 and US Pat. No. 4,927,254. The system is shown. As a pinhole array 4, a disk called a Nipco disk (Nipk0wDisc) in which pinholes 4a are arranged in a spiral pattern on a disk is used to rotate the disk. ing. By rotating the disk-shaped pinhole array 4, an image between the pinholes 4a, 4a is obtained by scanning.

However, in the conventional confocal optical device that forms an image of the reflected light from the object passing through the pinhole array 4 on the photodetector array 8 via the relay lens 7, the following is required. There was a problem.

(1) Reflected light from an object passing through each pinhole 4a of the pinhole array 4 is imaged on the photodetector array 8 in a one-to-one manner via the relay lenses 7, 7a, and 7b. In order to perform alignment, precise design and manufacture that take into account the aberrations of the relay lenses 7, 7a, and 7b are required, which requires many man-hours and precision parts. Was.

In addition, when each light detection portion (sensor) is very small compared to the pitch of the light detection portion of the photodetector array 8, the light signal (pinhole array) passing through each light detection portion and the pinhole 4a is used. There is a limit to precise alignment with the optical axis of ray 4). Ma In addition, due to manufacturing variations of the relay lenses 7, 7a, and 7b, there was a possibility that complete alignment could not be performed.

In order to solve this problem, if the image formed on the photodetector array 8 is defocused by shifting the arrangement of the photodetector array 8 in the Z direction, etc. However, in this case, since the intensity distribution of the image becomes non-uniform, the total amount of light passing through the pinhole 4a cannot be known.

(2) If the size of the pinhole 4a of the pinhole array 4 is larger than the diffraction limit of the optical system (objective lens),

Image magnification of relay lens 7, 7a, 7b X Pinhole 4a ¾

= Diameter of the pinhole image formed on the detector

Therefore, if each light detection portion is very small compared to the pitch of the light detection portion of the photodetector array 8, the pinhole image protrudes from the light detection portion, and in this case, too, the pinhole 4a Cannot know the total amount of light passing through.

In this case, if the converging optical system projects the object on the object and the light converging point coincides with the object surface, that is, if the object deviates even slightly from the so-called in-focus state as shown in Figs. 9 and 10 In this case, the light beam passing through the pinhole 4a is kicked by the non-photosensitive portion of the photodetector array 8, and the photodetection portion 8a acts as a substantial light receiving pinhole. It will be. In FIG. 10, in the image of the light passing through the pinhole 4 a, the image on one side indicated by hatching is out of focus as shown in FIG. 10. Ray 8 deviated from the light detection part and could not be detected by light detection part 8a. H

If the cost of the photodetector array 8 is to be reduced by using a commercially available imaging sensor such as a CCD camera, for example, a commercial version of the photodetector array 8 will be used. The above problem is important because each light detection portion is much smaller than the pitch of the light detection portion 8a, that is, many have a small aperture ratio. In addition, the shape of the light detection portion 8a is poorly isotropic, such as a rectangle, a letter, a convex, etc., in addition to a highly isotropic shape such as a circle or a square. It happens anisotropically depending on the direction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and facilitates alignment of a photodetector array, and further includes a photodetector array having a substantially large aperture ratio. It is an object of the present invention to provide a confocal point optical device capable of performing a focusing operation.

Disclosure of the invention

A first aspect of the confocal optical system according to the present invention for achieving the above object is as follows:

It has a confocal optical system including a relay lens, a pinhole array in which pinholes are arranged one-dimensionally or two-dimensionally, and a photodetector array, and measures the amount of reflected light from an object passing through each pinhole. In a confocal optical device for measuring with the photodetector array via the relay lens,

A diffusing member that randomly diffuses the reflected light passing through each of the pinholes is disposed near the focus position of the reflected light, and the reflected light passing through each of the pinholes is filled with a certain probability. The light is incident on the light detection portion of the light detector array. Further, in the above configuration, the diffusion member is arranged behind the front pinhole array.

Further, the diffusing member is disposed in front of the photodetector array.

A second aspect of the confocal optical system according to the present invention is as follows.

It has a confocal optical system including a relay lens, a pinhole array in which pinholes are arranged in one or two dimensions, and a photodetector array. In a confocal optical device for measuring the amount of light with the photodetector array via the relay lens,

The relay lenses are arranged in tandem between the pinhole array and the photodetector array, and the reflected light passing through each of the pinholes is randomly diffused between the relay lenses. A diffusing member is arranged so that the reflected light passing through each of the pinholes is evenly and uniformly incident on a light detection portion of the photodetector array.

According to the above configuration,

The reflected light from the object passing through the pinhole of the pinhole array is placed between the relay lenses located behind the pinhole array, in front of the photodetector array, or in tandem. Since the light is randomly diffused by the arranged diffusion member, the reflected light passing through the pinhole is uniformly incident on the light detection portion of the photodetector array with a certain probability.

A third aspect of the confocal optical system according to the present invention is as follows.

One-dimensional confocal optical system including relay lens and pinhole Or a two-dimensionally arranged pinhole array and a photodetector array, and the amount of reflected light from an object passing through each pinhole is reflected by the photodetector array via the relay lens. In a confocal optical device that measures at

The relay lens is arranged in tandem between the pinhole array and the photodetector array, and the reflected light passing through each of the pinholes is regularly diffracted between the relay lenses. A diffraction grating is arranged so that the reflected light passing through each of the pinholes is made incident according to the shape of the light detection portion of the light detector array.

According to this configuration,

The reflected light of the object that has passed through the pinhole is regularly diffracted by the diffraction grating, and is incident according to the shape of the photodetector portion of the photodetector array.

In the above configuration,

The positional relationship between the pinhole array and the photodetector array is set so that an image of one pinhole of the pinhole array can form an image at a plurality of light detecting portions of the photodetector array. Integrating means for integrating the outputs of the plurality of light detection portions on which the images are formed may be provided.

According to this configuration, even if there is a light amount distribution of the image, this is integrated, so that the aperture ratio of the light detecting portion of the light detector array is substantially enlarged.

Also, a micro lens array may be arranged in front of the photodetector array. According to this configuration, the light for forming the pinhole image, which is diffused by the diffusing member and the diffraction grating, is transmitted to each photodetector of the photodetector array by the micro lens array. It is focused on the part.

Therefore, according to the present invention, the pinhole of the pinhole array is formed by a diffusing member arranged behind the pinhole array, in front of the photodetector array, or between tandemly arranged relay lenses. Since the reflected light from the passing object is evenly blurred and averaged, the alignment of the photodetector array becomes easy, and the aberration of the relay lens is also a problem. Therefore, the design and construction of the layout relationship between the relay lens and the photodetector array with respect to the pinhole array can be simplified.

In the case where the diffraction grating is arranged between the tandemly arranged relay lenses, the light passing through the pinhole according to the shape of the photodetector portion of the photodetector array is formed by the diffraction grating. By dispersing the light, the alignment of the photodetector array is facilitated, and the same effect as that obtained by using the diffusion member can be obtained.

In addition, the light that has passed through one pinhole is diffused, measured at multiple photodetector sections, and integrated, creating a photodetector array with a substantially large aperture ratio. Can be.

In addition, by disposing the micro lens array in front of the photodetector array, the diffused member or diffraction grating can uniformly diffuse the blurred pinhole image. The light is condensed on each photodetector by the lens, and the light detection efficiency is improved. BRIEF DESCRIPTION OF THE FIGURES The invention will be better understood from the following detailed description and the accompanying drawings illustrating an embodiment of the invention. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding.

In the figure,

FIG. 1 is an explanatory diagram illustrating a configuration of a conventional confocal optical device.

FIG. 2 is an explanatory diagram showing an image forming state of a reflected light near a pinhole in the conventional device.

FIG. 3 is an explanatory diagram showing an image forming state of a reflected light near a pinhole in the conventional device.

FIG. 4 is an explanatory diagram showing an image forming state of a reflected light near a pinhole in the conventional device.

FIG. 5 is an explanatory view of the configuration when exposing the hologram.

FIG. 6 is an explanatory diagram of a configuration of a first conventional optical system.

FIG. 7 is an explanatory diagram of a configuration of a second conventional optical system.

Fig. 8 is a configuration diagram of a conventional nip code disc type optical system.

FIG. 9 is an explanatory diagram showing how light passing through the pinhole is kicked by the photodetector array.

FIG. 10 is an explanatory diagram showing how light passing through a pinhole is kicked by a photodetector array.

FIG. 11 is a structural explanatory view showing a first embodiment of the confocal optical device according to the present invention.

FIG. 12 is an operation explanatory view of the first embodiment of the present invention. FIG. 13 is an operation explanatory view of the first embodiment of the present invention. FIG. 14 is an operation explanatory diagram of the first embodiment of the present invention. FIGS. 15A and 15B are operation explanatory diagrams showing a volume type diffusion member and two stacked type diffusion members, respectively.

FIG. 16 is an explanatory diagram of the operation in a state where the thin diffusion member is brought close to the pinhole array.

FIG. 17 is an explanatory diagram of the operation when the thick diffusion member is separated from the pinhole array.

FIG. 18 is an explanatory diagram of an operation when a thicker diffusing member is used. FIG. 19 is an explanatory diagram of a configuration of a second embodiment of the confocal optical device according to the present invention.

FIG. 20 is an operation explanatory view of the second embodiment of the present invention in a state where a focus is formed after passing through a pinhole.

FIG. 21 is an operation explanatory view of a second embodiment of the present invention in a state where a focus is formed at a portion passing through a pinhole.

FIG. 22 is an operation explanatory view of the second embodiment in a state where a focus is formed just before the pinhole.

FIG. 23 is a configuration explanatory view showing a third embodiment of the confocal optical device according to the present invention.

FIG. 24 is a configuration explanatory view showing a fourth embodiment of the confocal optical device according to the present invention.

FIG. 25 is a configuration explanatory view showing a fifth embodiment of the confocal optical device according to the present invention.

FIG. 26 is an explanatory diagram of the operation of the fifth embodiment of the present invention.

FIG. 27 shows a sixth embodiment of the confocal optical device according to the present invention. FIG.

FIG. 28 is an operation explanatory view of the sixth embodiment of the present invention.

FIG. 29 is an operation explanatory view showing a photodetector array according to a seventh embodiment of the confocal optical device according to the present invention.

FIG. 30 is a structural explanatory view showing an eighth embodiment of the confocal optical device according to the present invention.

FIG. 31 is an explanatory diagram of the operation of the eighth embodiment of the present invention.

FIG. 32 is a structural explanatory view showing an eighth embodiment of the confocal optical device according to the present invention.

FIG. 33 is an explanatory view showing a process for producing a polymer scattering type liquid crystal plate substrate.

FIG. 34 is an explanatory diagram showing a step of injecting a liquid crystal into a substrate. FIG. 35 is a cross-sectional view showing an example of a configuration in which a pinhole array and a diffusion member are integrated.

FIG. 36 is a sectional view showing a sectional structure of the pinhole array. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a confocal optical system according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First Embodiment A first embodiment of the present invention will be described with reference to FIGS. This embodiment relates to an improvement over the prior art shown in FIG. 1, and the same components as those of the prior art are denoted by the same reference numerals and description thereof is omitted.

The diffusion member 20 is arranged behind the pinhole array 4. At this time, the pinhole array 4, the two relay lenses 7a and 7b, and the inspection The spacing between the output arrays 8 is the same as the conventional one shown in FIG.

The effect is as shown in Fig. 12, Fig. 13, and Fig. 14. The light that has passed through the pinhole 4a of the pinhole array 4 enters the diffusion member 20 and is randomly diffused here, passes through the relay lenses 7a and 7b, and enters the photodetector array 8. Incident.

Fig. 12 shows the reflected light passing through the pinhole 4a and being focused at the diffusion member 20. Fig. 13 shows the focus at the position of the pinhole array 4 in front of the diffusion member 20. Figure 12 shows a state in which the focal point is formed before the position of the pinhole array 4, respectively.

When the focal point is formed at the diffusion member 20 as shown in FIG. 12, the reflected light is scattered at this focal point, and the focal point is formed as shown in FIGS. I 3 and 14. It is diffused by the diffusion member 20 from the part of the slightly enlarged area later. The diffused portion is indicated by a dotted pattern with a high density. Then, the light of the diffusion center region 21 indicated by a circle in this diffusion portion is sent to one light detection portion (sensor) 8a of the photodetector array 8 via the relay lenses 7a and 7b. Received. In this way, each light that has passed through the pinhole array 4a is diffused by the diffusion member 20 and the light in the diffusion central region 21 has a certain probability of being uniformly distributed over the photodetector array 8a. The light is detected at the light detection part 8a.

At this time, the light in the diffusion center region 2 i becomes blurred light because the light (object image) that has passed through the pinhole 4 a is diffused. Even this diffusion center area 2 1 At this time, the light passing through the pinhole 4a is averaged and becomes uniform light, and this light is detected by the light detection portion 8a of the detector array 8.

At this time, the case where the image of the surface of the diffusion lens 20 on the relay lens 7a side is accurately formed on the photodetector array 8 and the case where the image position of the image of the surface of the diffusion member 20 is formed There are two cases in which there is a photodetector array 8 before and after.In the former case, only the diffusion effect of the diffusion member 20 can be used, whereas in the latter case, the diffusion effect is additionally provided. The effect of blurring due to defocus is added, and the light that passes through the pinhole 4a and reaches the photodetector array 8 becomes more uniform. 'The diffusion member 20 has a flat plate shape, and is a volume type having a certain thickness t as shown in FIG. 15A and a certain distance (thickness) as shown in FIG. 15B. There are two types of diffusers, 20a and 20b, which are separated by t, and two types.

The diffusion effect varies depending on the thickness t of the diffusion member 20, the distance D from the pinhole 4a, and the diffusion characteristics. As a general tendency, the diffusion effect increases as the thickness t increases, but the light loss increases, and the diffusion effect decreases as the thickness t decreases. Also, the diffusion effect increases as the number of diffusion plates stacked increases, but the light loss increases. The greater the distance D from the pinhole 4a, the lower the uniformity of the diffusion, and the smaller the D, the higher the uniformity of the diffusion. Also, the diffusion effect increases as the diffusion characteristic (angle) increases, and the diffusion effect decreases as the diffusion characteristic (angle) decreases. Therefore, it is only necessary to take these factors into account and make it appropriate diffusion (blur condition).

Fig. 16, Fig. 17, and Fig. 18 show the situation. Fig. 16 In the example shown in Fig. 7, a thin diffusion member 20 is arranged at a short distance from the pinhole 4a, and the diffusion effect is small and the degree of blur is small. The one shown in Fig. 17 has a thickness t larger than that shown in Fig. 16 and is farther away from the pinhole 4a by a distance D, so that the diffusion effect is larger and the degree of blur is larger. It is as large as whether or not it spans the adjacent photodetector array 8. The one shown in Fig. 18 uses a thicker diffusion member 20, the diffusion effect is even greater, and the degree of blur completely spans the adjacent photodetector array 8. You.

As the degree of blur increases, the alignment of the detector array 8 becomes easier. In particular, in the state shown in FIG. 17, precise alignment of the detector array 8 becomes unnecessary. However, when blurring large as shown in Fig. 18, it is necessary to consider that the light from adjacent pinholes 4a is mixed and measured.

Examples of the diffusion member 20 include: (1) a material in which the surface of an optical substrate made of glass or the like is subjected to processing such as grinding and etching so that the surface scatters light; The material itself has the property of scattering light (volume scattering), or (3) A material that scatters the volume in this way is coated on an optical substrate, for example, a coating or sand switch such as opal glass. There is something. A well-known polymer scattering type liquid crystal plate is used as the volume scattering type diffusion member 20.

In the above embodiment, as shown by the solid line in FIG. 11, the diffusion member 20 is arranged behind the pinhole array 4, but as a second embodiment, it is shown by the solid line in FIG. 19. Thus, the diffusion member 20 1 f

It may be arranged before the detector array 8.

The operation in the second embodiment is as shown in FIGS. 20, 21, and 22. That is, as shown in FIG. 20, when light is focused after passing through the pinhole 4a of the pinhole array 4, the light is defocused by the diffusion member 20 and has a large area. Spread. FIG. 21 shows a state in which light is focused on the pinhole 4a, and the light is diffused on a small surface. FIG. 22 shows a state in which light is focused before the pinhole 4a, and the light is diffused out of focus.

The configuration according to the present invention can also be applied to the first conventional type three-dimensional shape inspection apparatus shown in FIG. 6 and the second conventional type three-dimensional shape inspection apparatus shown in FIG. In the third embodiment shown in FIG. 23, the configuration of the first embodiment of the present invention is applied to the first conventional type. In this case, the diffusion member 20 is arranged behind the pinhole array 4 or in front of the photodetector array 8 as shown by a chain line. In this case, the relay lens 7 is not arranged in tandem, but this is not an essential difference. However, in the embodiment of the present invention, it is preferable that the relay lenses have a tandem arrangement. This is because in all confocal units, the blurring of the image by the diffusing member spreads evenly around the principal axis of each confocal unit.

In the fourth embodiment shown in FIG. 24, the configuration of the second embodiment of the present invention is applied to the second conventional type, in which a diffusing member 20 is disposed in front of the photodetector array 8. are doing.

FIG. 25 shows a fifth embodiment of the present invention, in which the parallel light between the relay lenses 7a and 7b in which the diffusion member 20 is arranged in tandem is shown. It is located in the department. In this embodiment, it is desirable that the diffusion member 20 has a very small diffusion effect such as an extremely thin diffusion member or a member having a narrow diffusion characteristic (angle).

Further, as in the sixth embodiment shown in FIG. 27, a diffraction grating 22 may be used instead of the diffusion member 20.

The operation of the fifth and sixth embodiments is as shown in FIGS. 26 and 28. Fig. 26 shows the case where an extremely thin diffusion member 20 is used.In this case, the light passing through the pinhole 4a is diffused between the two relay lenses 7a and 7b in a tandem arrangement. The light is incident on the photodetector array 8 blurred.

FIG. 28 shows a case where a diffraction grating 22 is arranged in place of the diffusion member 20. In this case, the diffraction grating 22 is of an amplitude type or a phase type, and the (0) th order light is used. The (+1) -order light and the (-1) -order light form an image on the photodetector array 8. At this time, if the diffraction direction is set in accordance with the direction of the light detection portion 8a of the photodetector array 8, it is possible to obtain a directional distribution.

Further, in this embodiment, the one-dimensional diffraction grating 22 is used, but this may be diffracted in both the X and Y directions by using a two-dimensional diffraction grating. Further, when this diffraction grating 22 is used together with the above-described diffusing member 20, the distributions are not discrete distributions of the (0) -order light, the (+1) -order light, and the (1-1) -order light. Since the next light is blurred and forms an image, the image distribution becomes smooth as a whole, and more favorable results are obtained.

FIG. 29 shows a seventh embodiment of the present invention. In this case, the pinhole image formed on the photodetector array 8 is defocused, or the pinhole image 23 is formed by the first to third diffusion members 20. The light passing through one pinhole 4a is received by a plurality of light detecting portions 8a, and the light is integrated.

In this embodiment, unlike the above-described embodiments, the light passing through one pinhole 4a is defocused or uniformly blurred, and the light is measured by a plurality of light detection portions. However, since they are integrated, they are integrated even if the light intensity distribution of the image is uneven. Therefore, when the plurality of light detection portions 8a are grouped into one photodetector, there is substantially the same (approximate) effect as an increase in the aperture ratio of the photosensitive portion of the photodetector. . In each of the above embodiments, when a light source with high coherence such as a laser is used as the light source and a commercially available CCD sensor or the like is used for the photodetector array, the light in the sensor cover glass is used. It is effective to remove the cover glass and fill a refraction liquid for optical matching between the cover glass and the sensor for the purpose of reducing interference.

In the first to fifth embodiments, when the diffusion member 20 is vibrated in the XY plane or rotated about the Z axis, the diffusion effect becomes higher.

FIG. 30 shows an eighth embodiment of the present invention. In this embodiment, the diffusion member 20 is arranged behind the pinhole array 4 and the microphone is arranged in front of the photodetector array 8. Place the lens array 24.

In this embodiment, as shown in FIG. 31, the light diffused uniformly in the pinhole array 4 is generated by each micro lens 24 a of the micro lens array 24. Since the light is condensed on each light detection portion 8a of the photodetector array 8, the light detection efficiency at the light detection portion 8a is improved.

In the eighth embodiment, as described above, the diffusion member 20 is arranged behind the pinhole array 4 and the photodetector array is arranged. The micro lens array 24 is placed in front of the lens 8 and diffracted between the two tandem relay lenses 7a and 7b as shown by the dashed line in Fig. 32. A grid 22 may be arranged.

Further, in the eighth embodiment, although not shown, a diffusion member 20 is arranged between the relay lenses 7a and 7b instead of the diffusion member 20 behind the pinhole array 4, This may be combined with the micro lens array 14 described above.

As one example of the diffusion member 20 used in each of the above embodiments, there is a polymer scattering type liquid crystal plate as described above. One example of a method of manufacturing this scattering type liquid crystal plate is shown in FIGS. 33 and 34. Shown in

First, as shown in each step of Fig. 33, (1) a UV adhesive 25 curable by ultraviolet rays and glass beads 26 are mixed, (2) agitated, and (3) a dispenser 2 At 7, two optical glass plates 2 8 a,

It is applied to both sides in the width direction of one glass plate 28a of 28b, and (4) bonded to the other glass plate 28b, and irradiated with ultraviolet rays to be cured. Thus, a substrate 29 having a space corresponding to the applied thickness of the adhesive containing beads is completed.

Next, as shown in each step of Fig. 34, (1) Photopolymer

30 and the liquid crystal 31 are weighed and mixed by an electronic balance 32, and (2) agitated with a stirrer 34 in a state where the magnet 33 is inserted. By injecting into the space of the substrate 29 on 5 by capillary action, and then irradiating it with ultraviolet rays to cure and seal it, a high molecular scattering type liquid crystal plate is completed.

When the diffusion member 20 is disposed immediately behind the pinhole array 4 or shortly before, the liquid crystal liquid is used for the diffusion member 20. In this case, both may be integrated. Fig. 35 shows an example of the structure. In this case, the pinhole array 4 is sealed between the optical glass substrates 28a and 28b together with the photopolymer 30 and the liquid crystal 31.

In addition, it is desired that the pinhole array 4 used in each of the above embodiments has a low reflectance when irradiated with light, and has a property of being hardly transmitted. An example of the structure is shown in Figure 36. This structure has a structure in which an intermediate layer 38 made of Cr is sandwiched between a first layer 37a made of Cr203 and a second layer 37b on BK7 glass 36. It has become. In the case of this structure, the layer thickness of Cr203 of the first layer 37a is related to the magnitude of the reflectivity, and by setting this thickness to 5 Omm, the reflectivity can be made almost zero. Can be.

The transmittance is related to the Cr of the intermediate layer 38, and the transmittance becomes smaller from 0.1 to 0.001 as the thickness increases from 5 Omm to 90 mm.

Although the present invention has been described with reference to exemplary embodiments, various modifications, omissions, and additions can be made to the disclosed embodiments without departing from the spirit and scope of the present invention. Is obvious to those skilled in the art. Therefore, the present invention is not intended to be limited to the above embodiments, but is to be understood as including the scope defined by the elements recited in the claims and their equivalents. There must be.

Claims

The scope of the claims

1. A confocal optical system including a relay lens, a pinhole array in which pinholes are arranged one-dimensionally or two-dimensionally, and a photodetector array. A confocal optical device for measuring the amount of reflected light with the photodetector array via the relay lens,

A diffusing member that randomly diffuses the reflected light passing through each of the pinholes is disposed near the focus position of the reflected light, and the reflected light passing through each of the pinholes is filled with a certain probability. A confocal optical device adapted to uniformly enter the light detecting portion of the light detector array.

2. The confocal optical device according to claim 1, wherein the diffusion member is disposed behind the pinhole array.

3. The confocal optical device according to claim 1, wherein the diffusing member is disposed before the photodetector array.

4. Equipped with a confocal optical system including a relay lens, a pinhole array in which pinholes are arranged one-dimensionally or two-dimensionally, and a photodetector array. A confocal optical device for measuring the amount of reflected light with the photodetector array via the relay lens,

The relay lens is arranged in tandem between the pinhole array and the photodetector array, and the reflected light passing through each of the pinholes is relayed between the relay lenses. Diffusion part to spread randomly A confocal optical device in which a material is arranged so that the reflected light passing through each of the pinholes is uniformly incident on the light detection portion of the photodetector array with a certain probability.

5. Equipped with a confocal optical system including a relay lens, a pinhole array in which pinholes are arranged one-dimensionally or two-dimensionally, and a photodetector array, reflecting light from objects passing through each pinhole A confocal optical device for measuring the amount of light with the photodetector array via the relay lens,

The micro lens is arranged in tandem between the pinhole array and the photodetector array, and the reflected light passing through each of the pinholes is regularly diffracted between the relay lenses. A confocal optical device in which a diffraction grating is arranged so that the reflected light passing through each of the pinholes is made incident according to the shape of a light detection portion of the photodetector array.

6. The positional relationship between the pinhole array and the photodetector array is set so that an image of one pinhole of the pinhole array can be formed at a plurality of light detection portions of the photodetector array. The confocal optical device according to any one of claims 1 to 5, further comprising integrating means for integrating outputs of the plurality of light detection portions on which the images of the holes are formed.

7. The confocal optical device according to claim 1, wherein a microlens array is arranged in front of the photodetector array.