JPH05343447A - Illuminator for image recognition device - Google Patents

Abstract

PURPOSE:To eliminate failure of an image recognition operation by optimizing a quantity of light incident to imaging means in response to a surface roughness of an object to be detected in the operation of an electronic component. CONSTITUTION:An to be detected and a light input unit 3a of imaging means 3 for imaging the object W are so disposed that an incident optical axis 10 of an optical system of the unit 3a becomes parallel with a normal of a surface to be detected of the object W, and a translucent mirror 9 such as a half prism, etc., is disposed on the axis 10 between the object W and the means 3. Two light sources 11, 12 are so disposed that an illuminating light from the first light source 11 is emitted substantially to the same axis as the axis 10 to the surface to be detected of the object W through the mirror 9 and the axis of the light from the second light source 12 to the object W has a suitable inclining angle theta to the axis 10. When a surface roughness is low the source 11 is fired through switching means 17 by a command signal from a controller 13 according to a difference of the surface roughnesses of the detected surfaces, while when the roughness is high the source 12 is fired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device in an image recognition device used for various operations of electronic components such as die bonding of integrated circuits (ICs) and wire bonding.

[0002]

2. Description of the Related Art Conventionally, die bonding work for mounting and bonding a semiconductor pellet of an IC on a predetermined island position of a lead frame, wire bonding between the electrode part of the semiconductor pellet and the lead part of the lead frame, and Wiring part on a ceramic substrate such as a thermal head, and a driving IC fixed on the ceramic substrate
In the wire bonding work with the electrode part in 1), image processing is performed from an image captured by a television camera to detect a mark part such as a mounting position of the semiconductor pellet or an electrode position.

In this case, if the object to be detected is arranged such that the incident optical axis line to the optical system of the television camera and the surface of the mark part on the object to be detected are substantially at right angles, the mark part on the object to be detected is arranged. The calculation of the coordinates of the detection position is easy. By the way, in order to facilitate the position detection of the mark part, the imaging area of the surface of the object to be imaged by the television camera is irradiated with illumination light. However, the mark part has a surface roughness like a lead frame. Rough surface and a surface portion having a smooth mirror-like surface such as a semiconductor pellet.

In these cases, the incident optical axis from the illuminating device with respect to the normal line of the mark detection surface is not 0 degrees (normal direction to the detection surface, in other words, vertical), but has an inclination angle. When, the reflected light totally reflected by the smooth (mirror-like) detection surface is reflected at the same angle (reflection angle) as the incident angle with the normal to the detection surface sandwiched.

Therefore, in order to image a mirror-like detection surface so that it looks bright and good, as shown in FIG. 2, the incident optical axis line 101 with respect to the optical system of the light entrance portion of the image pickup means 100 such as a television camera is set. While being set in a state of being perpendicular to the surface of the detected object 102, the image pickup means 100 and the detected object 1 are set.
02, the half prism 103 is arranged between the two and the irradiation light of the illuminating device 104 is put into the half prism 103 from the side thereof so that the incident light and the reflected light on the surface of the object to be detected 102 are coaxial. It is preferable to set. This irradiation method is hereinafter referred to as coaxial irradiation.

The half prism 103 is a prism in which a metal thin film (chrome film) or a dielectric multilayer film is coated on the slope of a right-angled prism, and the two right-angle prisms are adhered on both slopes. Vertical (right angle)
The light incident on is separated into reflected light and transmitted light on the slope. On the other hand, on the rough detection surface of the mark portion, the reflected light with respect to the incident light having the inclination angle is diffusely reflected and only a part of the incident light is incident on the image pickup means. As described above, when the incident light and the reflected light on the surface of the object to be detected 102 are set so as to be coaxial with each other, the amount of the reflected light to the light incident portion of the image pickup means 100 is extremely reduced due to the diffuse reflection, and the background portion and As a result of the loss of the contrast, the inconvenience occurs in image recognition and position detection. In order to eliminate this inconvenience, conventionally, as shown in FIG. 3, so-called tilted irradiation is performed in which the axis line 106 of the irradiation light with respect to the surface of the detection object 102 of the illumination device 105 is appropriately inclined by an angle (α). Preferably.

However, conventionally, when performing the image recognition operation of the object to be detected which has a portion having a different surface roughness, the two illumination systems of the coaxial irradiation and the tilted irradiation are simultaneously turned on.

[0008]

However, as described above, if two systems of lighting devices are simultaneously turned on to perform the image recognition work, the amount of light incident on the light incident portion of the image pickup means 100 such as a television camera is required. The number of images becomes larger than the above, and on the contrary, image recognition or detection of the mark portion becomes difficult or impossible.

For example, in the case of recognizing an image of a mark portion on a rough surface, a part of the irradiation light by the coaxial irradiation enters the image pickup means 100 in addition to the reflected light by the oblique irradiation, which hinders the image recognition and detection. There was a problem. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above conventional problems and provide an illuminating device in an image recognition device that can easily and accurately perform image recognition.

[0010]

In order to achieve the above-mentioned object, the present invention provides an object to be detected and a light entrance portion of an image pickup means for picking up the object, in which an optical axis of an optical system of the light entrance portion is detected. An illuminating device in an image recognition apparatus, which is arranged so as to be parallel to a normal line of a detection surface of an object, and includes a light source that irradiates the object to be detected with two systems. A semi-transparent mirror body such as a half prism is arranged on the optical axis between the two, and the irradiation light from the first light source is irradiated to the detection surface of the object to be detected through the semi-transparent mirror body substantially coaxially with the optical axis. On the other hand, the two light sources are arranged so that the axis of the irradiation light from the second light source to the object to be detected has an appropriate inclination angle with respect to the optical axis, and due to the difference in the surface roughness of the detection surface,
It is provided with a control means for switching ON / OFF of the irradiation of the first light source and the second light source or switching between increase and decrease of the light amount.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment embodying the present invention will be described. FIG. 1 is a schematic configuration diagram of an image recognition device 1 and an illumination device 2 of the present invention, and reference numeral 3 is a television camera or a two-dimensional image. Reference numeral 4 is an XY table on which an object to be detected W such as a semiconductor pellet is mounted.

The XY table 4 is moved in the X-direction by an X-axis motor 5 having a position detector 6 such as a rotary encoder, while it is moved in the Y-direction by a Y-axis motor 7 having a position detector 8 such as a rotary encoder. Is configured to move to. A stepping motor or the like is used for both the motors 5 and 7. The incident optical axis 10 with respect to the optical system of the light entrance part 3a of the image pickup means 3 is set at a right angle to the surface of the detected object W on the XY table 4, while the detected object W on the XY table 4 is set. The semi-transparent mirror body 9 is disposed between the light-receiving part 3a of the image pickup means 3 and the light-receiving part 3a. The semi-transparent mirror body 9 is composed of a half prism or a half mirror. These semi-transparent mirror bodies 9 are set such that the coating surface (inclined surface) described later is inclined at 45 degrees with respect to the incident optical axis line 10.

The half prism is a right-angled prism whose slope is coated with a metal thin film (chrome film) or a dielectric multilayer film, and these two right-angled prisms are adhered to each other on both sides thereof. ) Is incident on the slope and can be separated into reflected light and transmitted light. In the half prism, the reflected light and the transmitted light have the same optical path length, and there is no deviation of the optical axis of the transmitted light with respect to the incident light. Further, in the half prism, the ratio of the reflected light and the transmitted light is usually 1: 1.

The half mirror is formed by coating a metal thin film (chrome film) or a dielectric multilayer film on one surface of parallel plane glass, and splits light incident at 45 degrees into reflected light and transmitted light. However, depending on the plate thickness of the parallel-plane glass, the transmitted light is slightly displaced from the incident light in the optical axis. Reference numeral 11 denotes a first light source in the illumination device 2 of the present invention, the first light source 11 being arranged laterally of the semi-transparent mirror body 9 and being arranged in a direction orthogonal to the incident optical axis 10 of the first light source 11. The irradiation light is set so as to enter the semi-transparent mirror body 9. The second light source 12 is set so that the axis of the irradiation light is inclined by an angle θ with respect to the normal line to the detection surface of the object W to be detected on the XY table 4. The inclination angle θ of the second light source 12 can be changed and adjusted manually or by an actuator (not shown).

The image recognition device 1 and the illumination device 2 are controlled by an electronic control device 13 such as a computer as described below. That is, the control device 13 controls the central processing unit (CP
U), a read-only memory (ROM) that stores a control program, a readable / writable memory (RAM) that stores various kinds of setting data such as patterns and positions of the mark portion of the object to be detected, and input / output Main components are an interface and a bus for transmitting data and control signals to them. Further, the image data picked up by the image pickup means 3 is subjected to image processing such as binarization and emphasis by the image recognition circuit 14.

The X-axis motor 5 and the Y-axis motor 7 are CPUs.
Driven by drive circuits 15 and 16 in response to a command signal from the CPU, the rotation amounts of the X-axis motor 5 and the Y-axis motor 7 are detected by the detection signals of the position detectors 6 and 8, and the values are detected by the CPU. Entered in. Reference numeral 17 is a switching means for controlling the ON / OFF switching of the irradiation of the first light source 11 and the second light source 12 and the increase / decrease switching adjustment of the irradiation light amount, which is controlled by the CPU. The first light source 11 and the second light source 12 are manually turned on by the manual switches 18 and 19, respectively.
It can be turned off, and is configured to increase or decrease the irradiation light amount of the first light source 11 and the second light source 12 by a variable resistor or the like not shown.

The control device determines whether the mark portion to be detected or image recognized on the object to be detected W is a lead frame portion having a rough surface or a semiconductor pellet portion having a smooth surface such as a mirror surface. Specify with 13.
In response to the command signal, the control device 13 switches the switching means 17
When the surface is a mirror surface (when the mark portion to be detected is designated on the semiconductor pellet), the first
The light source 11 is turned on and the second light source 12 is turned off.
At this time, the voltage applied to the first light source 11 is previously stored in the RAM.
The setting value is changed to the setting value stored in the above, and is set so that the irradiation light amount is optimum for detecting the mark portion.

As a result, the irradiation light from the first light source 11 is incident on the side surface of the semi-transparent mirror body 9, and a part of the light passes through the coating portion of the semi-transparent mirror body 9 and is directly transposed from the other lateral side surface. Get out in the direction. The remaining irradiation light is bent downward by 45 degrees at the coating portion and is reflected vertically toward the object to be detected W, and the light reflected on the detection surface of the object to be detected W is the same as the incident optical axis line 10. The light is incident on the lower surface of the semi-transparent mirror body 9 coaxially, part of the light passes through the coating portion and enters the light entering portion of the image pickup means 3 as it is, and the rest of the light returns to the original direction of the first light source. .. Therefore, it is possible to detect the predetermined mark portion without excess or deficiency of light irradiation.

When the mark portion has a rough surface, the switching means 17 is operated by the command signal from the control device 13 to turn off the first light source 11 (turn off) and turn on the second light source 12 (turn on). .. Also in this case, the applied voltage of the second light source 12 is changed to a set value stored in advance in the RAM or the like, and the irradiation light amount is set to be the optimum irradiation light amount for detecting the mark portion.

As a result, a part of the light emitted at an appropriate inclination angle θ with respect to the normal to the surface of the object to be detected W is diffusely reflected on the rough surface, and a part of the reflected light is coaxial with the incident optical axis line 10. Since it is incident on the lower surface of the semi-transparent mirror body 9 and a part of the incident light passes through the coating portion of the semi-transparent mirror body 9 and enters the light entering portion of the image pickup means 3 as it is, the predetermined mark portion is irradiated with light. It can be detected without excess or deficiency.

Note that the first light source and the second light source are turned on.
It is even more effective if the increase / decrease adjustment (switching) of the irradiation light amount is executed in addition to the switching of the turning-off.

[0022]

As described above in detail, according to the present invention, the object to be detected and the light entering portion of the image pickup means for picking it up are covered by the optical axis of the optical system of the light entering portion. The detection object is arranged so as to be parallel to the normal line of the detection surface, and a semi-transparent mirror body such as a half prism is arranged on the optical axis between the detection object and the imaging means, and irradiation from the first light source is performed. While irradiating the detection surface of the object to be detected through the semi-transparent mirror substantially coaxially with the optical axis, the axis of the irradiation light from the second light source to the object to be detected is appropriately set with respect to the optical axis. 2 so that it has a tilt angle
By arranging two light sources, the lighting device of the present invention is
A light source for irradiating the object to be detected with two systems is provided. The control means turns ON / OFF the irradiation of the first light source and the second light source due to the difference in surface roughness of the detection surface.
Alternatively, the increase / decrease of the light amount is switched. By doing so, the optimum detected illuminance can be automatically obtained according to the surface roughness of the object to be detected, and the frequency of failure in the image recognition work and the positioning work by the image pickup means can be reduced, which is reliable and accurate. It is possible to perform various image recognition work and positioning work.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram of a device of the present invention.

FIG. 2 is an explanatory diagram of a conventional technique.

FIG. 3 is an explanatory diagram of another conventional technique.

[Explanation of symbols]

 W Object to be detected 1 Image recognition device 2 Illumination device 3 Imaging means 3a Light entrance part 4 XY table 9 Semi-transparent mirror body 10 Incident optical axis line 11 First light source 12 Second light source 13 Control device 17 Switching means

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area H04N 7/18 B

Claims (1)

[Claims] 1. An object to be detected and a light entrance portion of an image pickup means for picking up the object are arranged such that an optical axis of an optical system of the light entrance portion is parallel to a normal line of a detection surface of the object to be detected. Then, in the illumination device in the image recognition device provided with the light source for irradiating the object to be detected with two systems, a semi-transparent mirror body such as a half prism is provided on the optical axis between the object to be detected and the imaging means. And irradiating the irradiation light from the first light source to the detection surface of the object to be detected through the semi-transparent mirror substantially coaxially with the optical axis, while the irradiation light from the second light source to the object to be detected is The two light sources are arranged so that the axis has an appropriate inclination angle with respect to the optical axis, and due to the difference in surface roughness of the detection surface,
An illumination device in an image recognition device, comprising: a control unit that switches ON / OFF of irradiation of the first light source and the second light source or increases / decreases the amount of light.