JPS63258159A - Optical reader - Google Patents

Abstract

PURPOSE:To easily attain optical adjustment by naked eyes by providing a transmission region having a thickness corresponding to an error of an image position satisfying the image forming condition in radiating an object by a visual light an a near infrared-ray. CONSTITUTION:A transparent member 7 made of a raw material such as glass provided with a transmission region 7a having a thickness corresponding to an error of a front side image forming distance in the error of optical parameter and a width transmitting the optical image of the object 2 and with an image forming section 7b forming the image to both faces opposed to a lens 3 via the lens 3 is provided so that its outer side 7' is correspondent to the position of the front side image forming distance f1 in reading by the near infrared-ray of the lens 3. Moreover, a 2nd radiation means 8 radiation the read face 1a of the read element 1 by a visual light is provided. The reading is applied by abutting the object 2 onto the outer side 7' of the transparent member 7 and radiating it by an infrared-ray by means of the radiating means 4.

Description

[Detailed Description of the Invention] [Summary] A transmissive region having a thickness corresponding to an error in image position that satisfies imaging conditions when an object is irradiated with visible light and near-infrared light, and a surface facing the lens. A transparent member equipped with an imaging section is provided so that the outside thereof coincides with an image position that satisfies the imaging condition when irradiated with near-infrared light from a lens, and the reading surface of the reading element is irradiated with visible light. A second irradiation means is provided to enable adjustment operations such as focus adjustment and optical axis alignment with the naked eye.

[Industrial application field]

The present invention relates to the structure of a reading device that reads an object by irradiating it with near-infrared light.

OCR (Optical Character Rea)
der: Optical character reader), OMR (Opt
Some optical reading devices, such as ical mark readers (optical mark readers) or facsimile machines, use light as a light source in which most of the effective energy for the reading system is in the invisible region, such as near-infrared light.

Adjustment work for the optical systems of these devices cannot be done with the naked eye because the wavelength components effective for reading the light source are in the invisible range, and requires a large number of man-hours, so improvements are desired.

[Conventional technology]

The optical reading device of the present invention is a type of OC that reads an object by illuminating the object with a light source containing invisible light such as near-infrared light.
This is applicable to R>OMR or facsimile devices.

That is, in monetary certificates, bank passbooks, and the like, multi-colored dropout inks are used to print entry positions, printing positions, notes, and background patterns, for example, to prevent forgery.

Dropout color ink has a high reflectance in the near-infrared region of the reading section (wavelengths of 800 to 101,000 nm), and can be read with the naked eye (using light with a wavelength of 380 to 780 r+m); It has a characteristic that it is reflected and cannot be read by a reading device.

Such dropout color inks come in many colors and are supplied by ink manufacturers.

Therefore, in order to optically process the bank-related media (hereinafter referred to as the subject) printed with background patterns etc. using dropout color ink as described above, light containing near-infrared invisible light as a main component is used. It is designed to read only characters and symbols printed or written in normal ink (generally black) without reading the dropout color. As shown in the perspective view of FIG.
Coupled Device: Charge Coupled Device) or MOS (Metal Oxide Sem1co
a reading element 1 such as a metal oxide film semiconductor), a lens 3 that forms an optical image of a subject 2 on the reading element 1, and an irradiation means 4 that irradiates the subject 2 with light containing near-infrared light as a main component. and a connector 5 for outputting information read by the reading element 1.

The lens 3 includes means for adjusting a focus 3a and an aperture 3b.

Further, as the irradiation means 4, a lamp made of, for example, tungsten, whose energy peak is in the near-infrared region can be used as long as it matches the sensitivity peak of the reading element 1.

When using such an optical reading device, optical adjustment work such as optical axis and focus adjustment is required.

However, the wavelength range to which the reading system is sensitive is invisible light, and the position that the naked eye focuses on is different from the position that the device focuses on, so it is not possible to adjust the focus visually, so use the following method. ing.

First, an oscilloscope 6 is connected to the connector 5 so that the output signal of the reading element 1 can be observed in the form of a waveform.

First, as shown in the figure, place the subject 2I on which a single line is printed with regular black ink, or the subject 2□ on which a striped pattern is printed with similar ink, at a predetermined position facing the lens 3. Set to .

When this is irradiated by the irradiation means 4 and read by the reading element 1, a waveform as shown in FIG. 7 (al) appears on the oscilloscope 6 in the case of the subject 2I.

Furthermore, in the case of subject 2□, a waveform as shown in FIG. 8(a) appears.

All of these represent poorly focused conditions, so
Adjust the focus 3a and aperture 3b of the lens 3 and
1 or so that the focus and image are sharp as shown in FIG. 8(b).

[Problem that the invention seeks to solve]

Optical adjustment is performed as explained above, but because the light source is invisible light, it cannot be done with the naked eye. An easy-to-work method of making adjustments is not possible because the optical parameters such as the focal length of the lens are different when the subject is irradiated with visible light and near-infrared light.

For this purpose, as explained in the prior art, it is necessary to use a measuring device such as an oscilloscope, and equipment such as an oscilloscope or an amplifier that amplifies and outputs the output signal of the reading element is required, and the equipment There was a problem in that it required a lot of man-hours for operation and other adjustment work.

[Means for solving problems]

FIG. 1 is a side view of the optical reading device of the present invention.

In the present invention, a transmission region 7a having a thickness corresponding to an error in the image position that satisfies the imaging condition when the subject 2 is irradiated with visible light and near-infrared light, and an image forming area on the surface facing the lens. A transparent member 7 having a portion 7b is provided so that its outer 7° coincides with the image position that satisfies the imaging condition when irradiated with near-infrared light from the lens 3, and the reading surface of the reading element 1 is A second irradiation means 8 for irradiation with visible light is provided.

[Effect]

Optical adjustments such as focus and aperture can be made by illuminating the reading surface of the reading element with visible light and adjusting the lens to form a sharp image on the imaging surface of the transparent member.

Furthermore, the difference in focal length between visible light and near-infrared light can be corrected by adjusting the thickness of the transparent member.

〔Example〕

1 to 8 show an embodiment of the present invention.

The same parts are given the same reference numerals and indicated by °ζ throughout the figures.

As described above, optical parameters such as the focal length of the lens 3 are different when reading the object 2 using visible light and when reading it using near-infrared light.

In the present invention, as shown in the side view of FIG. 1, among the errors in the optical parameters, the error in the front imaging distance has a thickness indicated by the arrow T), and transmits the optical image of the subject 2. width(
Transmission area (effective field of view) of arrow E)7. a, and a transparent member 7 made of a material such as glass, which has an imaging section 7b that forms an image of the reading surface of the reading element 1 through the lens 3 on both sides facing the lens 3, and the outer 7° of the transparent member 7 is a lens. It is provided so as to coincide with the position of the front imaging distance f when reading with near-infrared light in No. 3.

Furthermore, a second irradiation means 8 for irradiating the reading surface 1a of the reading element 1 with visible light is provided.

Reading is carried out by bringing the object (indicated by the two-dot chain line) into contact with the transparent member 7 at an outside 7° and irradiating it with an irradiating means (hereinafter referred to as the irradiating means of the box 1) 4 that emits infrared light.

That is, as shown in FIG. 2, optical parameters such as the focal length of the lens 3 are different when reading the object 2 with visible light and when reading with near-infrared light.

In the figure, "," is the object-side imaging distance when reading object 2 with near-infrared light, f2 is the image-side imaging distance, and adding f2 to f is the distance of near-infrared light. is the conjugate length of the case.

On the other hand, f and l are the object-side imaging distances when reading the object 2 with visible light, r21 is the image-side imaging distance, and (-
, + 1. Lo plus + is the conjugate length in the case of visible light.

Therefore, when the subject 2 is irradiated with visible light and when the subject 2 is irradiated with near-infrared light, f,
An error equal to the value obtained by subtracting fIo is generated.

For this reason, the thickness T of the transparent region of the transparent member 7 is approximately equal to the error margin.

Being approximately equal means that lens 3 has a depth of focus,
This is because, as long as the depth of focus is within this depth of focus, there is no practical problem even if they do not exactly match.

In the above, an error D' also occurs between the image-side imaging distances f, 2 and f2'', but the reading element 1 uses near-infrared light to capture the object 2.
It is fixed at the position f2 when irradiated with .

The imaging parts 7b provided on both sides of the transparent member 7 are, for example, semi-transparent parts in the shape of frosted glass, and are parts on both sides of the element array (array) that are not used for reading the reading elements 1 such as COD. It is used to form an image.

The second irradiation means 8 is provided with a lamp 9 that irradiates visible light on the outside of the reading device as shown in FIG.
The ED array 11 may be provided close to the reading element 1.

Below, a method of optical adjustment using the naked eye of an optical reading device having such a configuration will be described.

As mentioned above, for visible light and near-infrared light, the image-side imaging distance f
Although an error D'' occurs between t and 121, as described above, the reading element 1 is fixed at the position of the image-side imaging distance f2 when reading the subject 2 with near-infrared light.

Therefore, in order to perform adjustment using visible light, it is first necessary to correct the error D', and a dummy 12 having a thickness equal to the error D' is mounted on the reading element 1 as shown in the side view of FIG.

Alternatively, other reading elements, which have been corrected by adding the thickness error D' in advance, may be temporarily attached or replaced in order to adjust the entire substrate.

Next, the second irradiation means 8 irradiates the reading element 1 .

Then, as shown in FIG. 5, the element array 1al of the reading surface 1a of the reading element 1 is imaged on the imaging portion 7b of the transparent member 7.

The focus and aperture of the lens 3 are adjusted so that this image becomes sharper to the naked eye.

After the adjustment is completed, the dummy 12 is removed and the irradiation by the second irradiation means 8 is stopped to complete the process.

With this adjustment, the object 2 that abuts the transparent member 7 at 7 degrees outside will form the best optical image on the reading element 1.

In this way, adjustment can be easily and easily performed with the naked eye without requiring an expensive measuring device such as an oscilloscope.

〔Effect of the invention〕

As explained above, the optical reading device of the present invention can be used for OCR.
When applied to OMR, facsimile machines, etc., optical adjustment can be easily performed with the naked eye, resulting in great economical and industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a side view of the optical reading device of the present invention, FIG. 2 is a diagram showing the optical path length in visible light and near-infrared light, FIG. 3 is a side view showing another embodiment, and FIG. 5 is a side view showing the state in which the dummy is mounted on the reading element, FIG. 5 is a plan view showing the state in which the dummy on the reading element is imaged on the imaging section, and FIG. 6 is a perspective view of a conventional optical reading device. , Figure 7 (al
, (b) are diagrams showing waveforms read with an oscilloscope for a single-line object, and Figures 8(a) and (bl are diagrams showing waveforms read with an oscilloscope for a striped object. ■ is the reading element, Ia is the reading surface, 2 is the subject,
3 is a lens, 4 is a first irradiation means, 5 is a connector, 6 is an oscilloscope, 7 is a transparent member, 7a is a transmission area, 7b is an imaging section, 8 is a second irradiation means, 9 is a lamp, 10 is a A through hole, 11 is an LED array, and 12 is a dummy.゛・L) Mitsumiya accent of the present invention! Detective ``Men Prisoner High 1 Figures available to light and outside the world 1 Koga I to charge S to good Σ show 7 Figures Et! ,%'ta9'3 1teYmi]rii! a-J
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Claims (1)

[Scope of Claims] A reading element (1), a lens (3) that forms an optical image of a subject (2) onto the reading element (1), and a lens (3) that focuses an optical image of the subject (2) on the reading element (1); an irradiating means (4) for irradiating with light as a component, the irradiating means (4) irradiates the subject (2), and the reading element (1) captures an optical image through the lens (3). An optical reading device for reading, comprising: a transmission area (7a) having a thickness corresponding to an error in image position that satisfies imaging conditions when the object (2) is irradiated with visible light and near-infrared light, and a lens. An image position that satisfies the imaging condition when the outer side (7') of a transparent member (7) having an imaging section (7b) on opposing surfaces is irradiated with the near-infrared light of the lens (3). What is claimed is: 1. An optical reading device comprising: a second irradiation means (8) for irradiating the reading surface of the reading element (1) with visible light;