WO2020080071A1

WO2020080071A1 - Illumination device

Info

Publication number: WO2020080071A1
Application number: PCT/JP2019/038288
Authority: WO
Inventors: 誠竹島; 隆平山口; 祐輝久保; 越智　達也
Original assignee: 東レエンジニアリング株式会社
Priority date: 2018-10-16
Filing date: 2019-09-27
Publication date: 2020-04-23
Also published as: JP2020064734A; CN112912794A; TW202016587A; JP7086813B2

Abstract

Provided is an illumination device capable of emitting illumination light having uniformity and an amount sufficient for observing, imaging, inspecting, etc., a light transmissive workpiece exhibiting a lens effect. More specifically, this illumination device for emitting illumination light on a light transmissive workpiece having a lens effect is provided with: a light source; a light emitting part which guides light radiated from the light source and emits a light flux having a prescribed spread angle; a condenser lens part which converts the light flux having the prescribed spread angle into a parallel light flux; and a diffusion plate which allows the parallel light flux to pass therethrough so as to convert the parallel light flux into illumination light propagating in random directions.

Description

Lighting equipment

The present invention relates to an illumination device that emits illumination light used for observation, imaging, inspection, etc. of a light-transmitting work having a lens effect.

A lighting device that emits illumination light has been conventionally used to inspect the product for scratches or stains after it is completed or during manufacturing.

As a form of irradiating the illumination light required for observation, imaging, etc. onto a substrate (called a work) targeted for observation, imaging, inspection, etc., a housing containing a lamp serving as a light source (so-called It is well known that light emitted from a lamp box is guided by a light guide member, which is a bundle of optical fibers called a light guide.

Then, a method is known in which a lens is arranged at the emission part of the light guide to collimate the emitted light (for example, Patent Document 1).

Also, a method is known in which the emission ends of the optical fibers forming the light guide are arranged side by side in a flat manner, and planar illumination is obtained by light that has passed through the light transmission plate and the diffusion plate (for example, Patent Document 2).

It should be noted that which of the methods of Patent Documents 1 and 2 is used is appropriately selected and adopted depending on the surface state of the workpiece to be observed, working distance, observation magnification, scratches or stains to be found, and the like. It was

Japanese Utility Model Publication No. 6-33239 Japanese Utility Model Publication No. 6-21002

When trying to observe, image, or inspect a light-transmissive work having a lens effect, in the method of Patent Document 1 (that is, parallel light), the observation light that has passed through the light-transmissive work is biased by the lens effect and is uniform It becomes impossible to obtain a good light intensity distribution. Therefore, the conventional technique has a problem in that an appropriate light amount distribution cannot be obtained for detecting or detecting scratches or stains, and desired observation and inspection cannot be performed.

Further, the method of Patent Document 2 (that is, mere diffused light) has a problem that a sufficient amount of light cannot be obtained and desired observation and inspection cannot be performed.
Therefore, the present invention has been made in view of the above problems, and it is possible to irradiate illumination light having a sufficient light amount and uniformity for observation, imaging, inspection, etc. of a light-transmitting work having a lens effect. An object is to provide a lighting device.

In order to solve the above problems, one aspect of the present invention is
A lighting device for irradiating a light-transmitting work having a lens effect with illumination light,
A light source,
A light emitting portion that guides the light emitted from the light source to emit a light beam having a predetermined spread angle,
A condenser lens unit that converts a light beam with a predetermined divergence angle into a parallel light beam,
It is characterized in that it is provided with a diffusing plate that converts parallel light fluxes into illumination light whose traveling directions are random.

According to the above illumination device, since the light passing through the diffusion plate is diffused in the traveling direction at random, it is possible to reduce the bias of the observation light when observing a light-transmitting work having a lens effect. it can. Further, since the parallel luminous flux is guided until immediately before passing through the diffuser plate, it is possible to uniformly illuminate the entire visual field with a sufficient amount of light.

∙ It is possible to irradiate illumination light that has a sufficient light amount and uniformity for observation, imaging, inspection, etc. of a light-transmitting work having a lens effect.

It is a schematic diagram showing the whole example composition of the form which embodies the present invention. It is sectional drawing which shows the principal part of an example of the form which embodies this invention.

A mode for carrying out the present invention will be described below with reference to the drawings.

In the following description, the three axes of the Cartesian coordinate system are X, Y, and Z, the horizontal direction is expressed as the X direction and the Y direction, and the direction perpendicular to the XY plane (that is, the gravity direction) is expressed as the Z direction. To do. In the Z direction, the direction against gravity is expressed as up and the direction in which gravity works is expressed as down. Further, the direction of rotation about the Z direction as the central axis is the θ direction.

FIG. 1 is a schematic diagram showing an overall configuration of an example of a mode for embodying the present invention. FIG. 1 shows a schematic view of a lighting device 1 according to the present invention and an inspection device K incorporating the same.

The inspection device K is for inspecting the front surface, the back surface, and the inside of a light-transmitting work having a lens effect (referred to simply as the work W) for scratches, foreign matters, dirt, bubbles, and the like. The work W is made of thin plate silicon, glass, resin, or the like, and is formed into a predetermined pattern on the surface by film formation or etching, processed into a predetermined surface shape, or laminated with a functional material. Has been done. Specifically, the inspection device K includes the illumination device 1, the imaging unit C, the work holding unit H, the relative moving unit M, the computer CN, and the like.

The lighting device 1 irradiates the work W with illumination light. Specifically, the lighting device 1 includes a light source 2, a light emitting unit 3, a condenser lens unit 4, a diffusion plate 5, a housing 10, and the like.

The light source 2 emits light necessary for observation, imaging, inspection and the like.
Specifically, the light source 2 may be, for example, one that emits light in the visible light region, which is the sensitivity wavelength of the human eye or the imaging unit C, when a current or voltage is applied from the outside. More specifically, examples of the light source 2 include a xenon lamp, a metal halide lamp, a halogen lamp, a fluorescent lamp, an LED illumination, and a laser diode that emits light of a predetermined wavelength.

The light emitting section 3 guides the light emitted from the light source and emits the light flux L1 having a predetermined divergence angle. Specifically, the light emitting section 3 includes a light guide section 30 in which a large number of optical fibers are bundled, a reflection mirror 32, and the like. When the light guide section 30 allows light to enter the entrance end, the light guide section 30 repeats multiple reflection inside the fiber, and a light beam L1 having a predetermined divergence angle is emitted from the exit end 31.

The condenser lens unit 4 converts the light beam L1 having a predetermined spread angle into a parallel light beam L2. Specifically, the condenser lens unit 4 is composed of a plano-convex lens, an aspherical convex lens, a combination lens, and the like.

The reflection mirror 32 changes the direction of the parallel light flux L2. Specifically, the reflection mirror 32 is arranged in an oblique direction of 45 degrees, and is configured to convert the parallel light flux L2 emitted from the X direction into the parallel light flux L3 emitted in the Z direction. .

The diffuser plate 5 converts the parallel light flux L3 into illumination light 4 whose traveling direction is random. Further, the diffusion plate 5 is arranged with a predetermined distance d from the work W. More specifically, the diffuser plate 5 has a frosted glass-like concavo-convex treatment on the surface and / or the back surface of a transparent glass plate or white translucent plastic resin, and the traveling direction of incident light is diffused randomly. It has a characteristic (so-called diffusiveness) of being emitted as a result.

Therefore, the light L5 with which the work W is irradiated includes light from various directions, and even if the work W includes a portion having a lens effect, there is no bias in strength and weakness (that is, uniformity). Observation light L is obtained.

The housing 10 fixes the light emitting unit 3, the condenser lens unit 4, and the diffusion plate 5 in a predetermined positional relationship. Specifically, the housing 10 is arranged below the work W. More specifically, the housing 10 is made up of a box whose upper surface and side surfaces are partially open. The light emitting unit 3 is attached to the opening on the side surface of the housing 10, and the diffusion plate 5 is attached to the opening on the upper surface of the housing 10. Further, the condenser lens unit 4 and the reflection mirror 32 are attached inside the housing 10.

The image pickup section C picks up an image of the work W. Specifically, the image pickup unit C picks up an image including the inspection area R set on the work W and outputs the image to an external device. More specifically, the image pickup section C includes an image pickup camera C1, a lens C2, and the like.

The image pickup camera C1 includes an image pickup element (so-called image sensor) C3 such as CCD or CMOS, and the image in the field of view F formed by the observation light L on the image pickup element via the lens C2 or the like is converted into a video signal. Or image data can be output to an external device. Specifically, the image captured by the image capturing camera C1 is output to the computer CN. More specifically, the imaging unit C is arranged so as to look down on the work W from above, and the work W and the lens C2 face the diffusion plate 5 of the lighting device 1 with a predetermined working distance WD. It is located in a position.

The work holding unit H holds the work W in a predetermined posture. Specifically, the work holding unit H includes a work mounting table H1 and a suction mechanism (not shown).

The work placing table H1 holds the work W in a predetermined posture by contacting the lower surface and side surfaces of the outer peripheral portion of the work W and applying a frictional force or a suction force to the outer peripheral portion. Specifically, the workpiece mounting table H1 is provided with a suction groove or hole on the upper surface of a plate-shaped member arranged so that the upper surface is horizontal, and is connected to a suction mechanism via a switching valve or the like. Examples thereof include a structure (so-called negative pressure suction plate), an electrostatic suction plate, a grip chuck mechanism including an opening / closing mechanism.

The relative moving unit M relatively moves the image pickup unit C and the work holding unit H, and changes the location of the work W imaged by the image pickup unit C. Specifically, the relative movement unit M is configured to relatively move the illumination unit 2 and the image pickup unit C so as to face each other and the work placement table H1 holding the work W. More specifically, the relative moving unit M includes an X-axis stage, a Y-axis stage, and a θ-axis stage (not shown).

The X-axis stage moves the work mounting table H1 in the X direction or stops it at a predetermined position, and is mounted on the device frame (not shown).

The Y-axis stage moves the work mounting table H1 in the Y-direction or stops it at a predetermined position, and is attached to the X-axis stage.

The θ-axis stage rotates the work mounting table H1 or stops it at a predetermined angle, and is attached to the Y-axis stage.

The X-axis stage, the Y-axis stage, and the θ-axis stage are connected to a control unit (not shown), and move / rotate at a predetermined speed or a predetermined speed based on a control signal output from the control unit. It stops at the position and angle of.

The computer unit CN controls turning on / off of the lighting device 1, adjusting the intensity of illumination light, controlling the image pickup unit C, the work holding unit H, the relative moving unit M, and the like. Specifically, when a signal or data is input from a connected external device, the computer unit CN performs processing according to a program registered in advance and outputs the processing result to the external device. More specifically, the computer unit CN includes hardware such as an input / output device, a storage device, an image processing device, an arithmetic processing device, and an execution program (software).

Then, when the video signal (analog signal) or image data (digital signal) corresponding to the image output from the image pickup camera C1 of the image pickup unit C is input, the computer unit CN performs predetermined image processing on the image. Etc. and is programmed to perform a predetermined inspection.

FIG. 2 is a cross-sectional view showing a main part of an example of a form embodying the present invention. FIG. 2 shows the loci of the illumination light and the observation light L passing through the work W.

The observation light L is a light flux imaged by the imaging camera C1 of the imaging unit C, and includes a light flux Ld that has passed through the portion Sd of the work W having the lens effect and a light flux Lf that has passed through the portion Sf that does not have the lens effect. Is included.

In the case where the present invention is not applied, among the light fluxes emitted from the lower side of the work W to the vertically upper direction (that is, only parallel light rays), the light fluxes Lf that have passed through the portion Sf having no lens effect are Reach C. On the other hand, the light flux that passes through the portion Sd having the lens effect becomes a light flux that passes through the focal point position Fp as shown by the broken line, and does not reach the image pickup unit C or is a biased light. Therefore, the image pickup unit C cannot obtain a uniform light amount distribution. In addition, it was not possible to obtain an appropriate light amount distribution for detecting and detecting scratches and stains, and it was not possible to perform desired observation and inspection.

According to the illuminating device 1 of the present invention, the illumination light L5 emitted from the lower side to the upper side of the work W is a luminous flux having a random traveling direction because of the above-described configuration. Therefore, the light flux indicated by the solid line passes through the portion Sd having the lens effect and the portion Sf having no lens effect, and reaches the imaging unit C. Then, when observing the work W, the deviation of the observation light L can be reduced. Further, since the illumination light guided from the light source is guided as parallel luminous fluxes L2 and L3 until just before passing through the diffusion plate 5, it is possible to uniformly illuminate the entire visual field F with a sufficient amount of light.

In the above description, the configuration in which the upper surface of the work W is shaped like a convex lens is illustrated, but the present invention can be applied even if the lower surface or the upper and lower surfaces are shaped like convex lenses. Further, the upper surface and / or the lower surface may have a shape like a concave lens.

[Other forms]
In the above description, the illumination device 1 according to the present invention is incorporated in the inspection device K as an example. Such a form is preferable because it is possible to perform the automatic inspection while reducing the bias of the observation light L. However, in order to embody the present invention, it is not essential to incorporate it in the inspection device K, and the work W is held by the work holding table H and a person visually observes or inspects it (there is no imaging unit C). There may be a form. Alternatively, the work W may be manually held by a person and visually observed or inspected (there is no imaging unit C, work holding base H, relative moving unit M, or the like).

[Another form]
In the above description, the form in which the diffusion plate 5 is attached to the opening on the upper surface of the housing 10 of the lighting device 1 has been illustrated. However, the diffusion plate 5 is not limited to the form fixed to the housing 10, and may be a form attached so as to be vertically movable.

Specifically, the housing 10 of the lighting device 1 is provided with the diffusion plate distance adjusting unit 7.
The diffusion plate distance adjusting unit 7 adjusts the distance d between the work W and the diffusion plate 5.
Specifically, the diffuser plate distance adjusting unit 7 is configured to include an actuator having a movable unit that changes the position in the vertical direction. Then, the diffusing plate 5 is attached to the movable portion via a mounting member or the like.

The actuator changes its vertical position based on a control signal from the outside and makes it stand still at a predetermined position. Specifically, the actuator can be exemplified by a stage mechanism equipped with a ball screw and a stepping motor, a pneumatic cylinder, etc., and can be moved based on a control signal from the computer CN, a change in an electric signal by a switching SW, a potentiometer, or the like. An example is a configuration in which the vertical position of the unit is controlled.

With such a configuration, the distance d between the work W and the diffusing plate 5 can be changed while the light emitting unit 3 and the condenser lens unit 4 are fixed, so that the distance d suitable for the curvature of the work W is set. It is possible and preferable.

[Modification]
In the above description, the light emitting unit 3 is illustrated as having the light guide unit 30 in which a large number of optical fibers are bundled. Such a configuration is preferable because it is easy to appropriately move the housing 10 and attach it to the inspection device K or the like.

However, in embodying the present invention, the light emitting unit 3 is not limited to the configuration in which the light guide unit 30 is provided, and a portion where the light is emitted from the lamp box in which the light source 2 is housed (that is, the light emitting unit). The condenser lens unit 4 may be attached to the (corresponding to the unit 3).

DESCRIPTION OF SYMBOLS 1 Illumination device 2 Light source 3 Light emitting part 4 Condensing lens part 5 Diffusing plate 7 Diffusing plate distance adjusting part 10 Housing 30 Light guide 31 Emitting end 32 Reflecting mirror L Observation light L1 Luminous flux L2 with predetermined divergence angle Parallel luminous flux L3 Parallel light flux L4 Illumination light whose traveling direction is random L5 Illumination light partial light flux (light flux of a certain component)
W Light-transmissive work K Inspection device C Imaging unit H Work holding unit d Distance M Relative movement unit CN Control unit F Field of view R Inspection area C1 Imaging camera C2 Lens C3 Imaging device H1 Work stand

Claims

A lighting device for irradiating a light-transmitting work having a lens effect with illumination light,
A light source,
A light emitting part for guiding the light emitted from the light source to emit a light beam having a predetermined spread angle;
A condenser lens unit for converting a light beam having the predetermined divergence angle into a parallel light beam,
An illuminating device, comprising: a diffusion plate that converts the parallel light fluxes into illumination light whose traveling direction is random.
A work holding portion for holding the light-transmitting work,
The lighting device according to claim 1, wherein the light-transmissive work and the diffusion plate are arranged with a predetermined distance therebetween.
The lighting device according to claim 2, further comprising a diffusion plate distance adjusting unit that adjusts the distance between the light-transmissive work and the diffusion plate.
The lighting device according to any one of claims 1 to 3, wherein the light emitting unit includes a light guide unit in which a large number of optical fibers are bundled.