JPS58114279A - Video reading device - Google Patents

Abstract

PURPOSE:To eliminate a heat generation phenomenon caused by the lighting, and to read exactly and quickly pictures under different lighting conditions, by using an LED as the lighting means. CONSTITUTION:By a signal from a lighting source switching control circuit 6, light sources 1-3 and power supply for light sources 7-9 are selected and a sample 4 is lighted by the light sources 1-3 composed of LEDs. The video information of the sample 4 is outputted from an image pickup element 10 and, moreover, inputted into a picture image memory 13 through a TV camera driver 11 and an AD converting circuit 12. The lighting source switching control circuit 6 and the picture image memory 13 are controlled by a control system 14.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a double-image reading device, and more particularly to an image reading device that can control blinking switching of an illumination light source at high speed and read images under poor lighting conditions. It is something.

(2) Background of the technology In bonding to the bonding pads of integrated circuit (IC) chips disposed on ceramic substrates, secondary patterns of lead patterns, etc., there is a tendency for IC chips to become more densely packed. There is an increasing need for accurate and rapid position recognition of these chips and their pads.

(3) Prior Art and Problems In conventional apparatuses, a sample is illuminated using a heat lamp or the like, and image information is captured through the lens of a television camera. As illumination methods in this case, vertical epi-illumination using a vertical epi-illumination light source and oblique illumination method using an oblique illumination light source are conventionally known, but in one image reading device, one type of fixed illumination is used. Therefore, when reading the shape or recognizing the position of several types of samples with different shapes, using one type of fixed illumination method has many disadvantages, such as only vague position recognition. was occurring.

Regarding the control of illumination conditions such as illumination time, conventionally a light source equipped with a shutter mechanism has been used to control illumination conditions, for example, for Fra Nocié illumination light such as a stroboscope. For the former, the illumination light source itself is expensive, and for the latter, mechanical shutter drives have problems in terms of speed and operating life.

On the other hand, light emitting diodes (Light E++ittin
G Diodes (hereinafter abbreviated as LED) are used as a light source, as in the case of LED displays, which control blinking, but when used as an illumination light source,
Furthermore, a device that controls illumination time and also switches and controls illumination conditions such as vertical epi-illumination and oblique illumination has not been used in the past.

(4) Purpose of the Invention An object of the present invention is that by configuring an illumination light source switching circuit using LEDs as illumination light sources, the illumination system can be switched and controlled, and images under different illumination conditions can be read with a single image reading system. The purpose is to provide a method that can be read accurately and quickly.

(5) Structure of the Invention The features of the present invention include an imaging means, a plurality of illumination light sources each set to a plurality of illumination conditions, a power supply circuit for driving the illumination light sources, and illumination light source switching control for switching the plurality of illumination light sources. a circuit, an analog data conversion circuit to which an image signal obtained from the imaging means is applied, and an image memory to which an output of the analog data conversion circuit is applied and image data is stored, the illumination light source comprising a light emitting diode. The present invention provides an image reading apparatus which switches the illumination light source according to a plurality of different illumination conditions by the illumination light source switching control means and reads an image under the specified illumination condition.

(6) Embodiments of the Invention The present invention makes it possible to control lighting conditions by using an LED light source and an illumination light source switching control circuit that controls blinking of a plurality of these LEDs.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing the overall configuration of the present invention. In the same figure, regarding sample 4 to be recognized such as an IC chip or knob, the illumination light source is A signal from the switching control circuit 6 causes the light source 1. Electrical IT was selected and approximately 0.1
The vertical epi-illumination light source 1 is turned on by an LED installed on a line connecting the image sensor 1 on the vertical top surface of the sample 14 and the sample 4 for a period of μs, and the television camera displays video information of the sample 4 such as an IC chip. The image information captured by the image sensor 10 is converted into a video signal, and then passed through a television camera driver 11 and then converted into an analog-to-digital conversion circuit 12 for digitizing the video signal.
The image is converted into a digital signal or multi-valued and stored in the image memory 13. Both image data stored in the image memory 13 are outputted to the outside by a control system 14 as necessary so that video information can be extracted.

In addition, if the sample 4 has a rough surface such as a lead pattern, the illumination light source switching control circuit 6 is used to read the sample 4 using a so-called dark field illumination image.
The light source 2.3 provided diagonally at an acute angle with respect to the image is turned on, and image information such as the lead pattern 4 is input to the image memory 13 through the same route as above.

FIG. 2 is a time chart of image capture control by the control system. When the output signal from the illumination light source switching control circuit 6 is input to the light source 1 power supply 7, vertical epi-illumination is started, and vertical epi-illumination is performed for approximately 0.1 μs. The video signal input to the image sensor of the television circuit during this period is inputted by triggering the image capture at the time when the sample is sufficiently illuminated by the LED (when a certain amount of light is reached). That is, when the signal level of the image information captured by the television camera reaches a constant value, an image capture trigger is applied from the control system 14' and the image signal is stored in the image memory 13 via the analog-to-digital conversion circuit 12. As for oblique lighting, it's also a light for oblique lighting! 12.3 is manually input from the illumination light source switching control circuit 6 to the light j12 power source 8 and the light source 3 power source 9 to emit light for a predetermined period of time, and the image memory 13 is activated by the same control as described above. is stored in Of course, the modes of these illumination methods can also be changed arbitrarily.

(7) Effects of the Invention As explained in detail above, the image reading device of the present invention uses LEDs as the illumination means, so no heat is generated due to illumination, and therefore it does not respond subtly to changes in temperature, for example. It is preferable for image elements with the characteristics of This enables high-speed reading, reduces power consumption, and the unit price of LEDs is extremely low.Furthermore, the illumination light source switching control circuit makes it possible to switch the illumination light source according to the recognition target, making it easier to detect The S/N ratio was also significantly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the two-image reading device, and FIG. 2 is a diagram showing a time chart from the time when an image is taken in by the control system to when the image is captured. 1... Vertical epi-illumination light N (LED), 2°3.
...Light source for oblique illumination (LED), 4...Sample, 6...
- Illumination light source switching control circuit, 12... analog-to-digital conversion circuit, 13... image memory, 14... control system. Patent applicant Fujitsu Limited

Claims (1)

[Claims] an imaging means, a plurality of illumination light sources each set to a plurality of illumination conditions, a power supply circuit that drives the illumination light sources, an illumination light source switching control circuit that switches between the plurality of illumination light sources, and an illumination light source obtained from the imaging means. In an analog-to-digital conversion circuit to which an image signal is applied, and an image memory to which an output of the analog-to-digital conversion circuit is applied and imaged data is stored, the illumination light source is composed of a light emitting diode, and the illumination light source is configured from a light emitting diode, An image reading device characterized in that the illumination light source is switched by the illumination light source switching control means so that an image can be read under specified lighting conditions.