JPS6244308B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information reading device, and more particularly to a device for reading information recorded on an information recording sheet with a black ballpoint pen or the like.

Conventionally, in optical information reading devices, a light beam emitted from a light source is irradiated onto an information area on an information recording sheet, and the reflected light from black and white changes depending on the presence or absence of information in that information area is incident on a photoelectric conversion element. , a method of converting it into an electrical signal is adopted.

Figure 1 shows a schematic diagram of the method described above.
10 is an information recording sheet, 11 is a light source, 12 is an imaging lens, and 13 is a photoelectric conversion element. Now light source 1
1 as a tungsten lamp, a photoelectric conversion element 13
Consider the case where a CCD (Charge Coupled Device) is used.

Figure 2 shows the tungsten lamp 11 in Figure 1.
This shows the spectral characteristics of CCD13 and its total.
Since the spectral characteristics of the tungsten lamp 11 and CCD 13 are expressed as 11A and 13A, respectively, the overall spectral sensitivity characteristic of this system is 100A, which is 700A.
It can be seen that it has high sensitivity in the near-infrared region of mμ or more.

By the way, general black ballpoint pens are generally ranked 3rd.
It has the spectral characteristics as shown in FIG. 200A, and its spectral reflectance gradually rises from around red and shows a high value in the near infrared. On the other hand, for example, the spectral characteristics of a black pencil are 2
As shown by 01A, the reflectance is almost constant and low over the entire wavelength range. Therefore, when the above-mentioned combination of the tungsten lamp 11 and the CCD 13 performs photoelectric conversion of the reflected light of information recorded on the information recording sheet with a black pencil or a black ballpoint pen, in the former case, it is higher than the blank area of the recording sheet. Although contrast can be obtained, it can be seen that in the latter case, only low contrast can be obtained for the blank portion of the recording sheet.

Now, in a general information recording sheet, as shown in FIG. 6, in the blank section 30, necessary items or character frames 32, etc. are dropped outside the information recording section 31.The drop-out color is a color with low contrast after photoelectric conversion. ) is often printed. It is desirable that this drop-out color provides a strong sense of contrast to the human eye, but red-based colors are preferably used due to the visibility characteristics of the human eye.

The purpose of the present invention is to record information recorded with a black ballpoint pen or black pencil on an information recording sheet printed with a red dropout color (for example, orange, pink, red, etc.), and to record dropout colors other than red dropout colors. 3.20 on the information recording sheet printed with a printout color (for example, purple, blue, green, etc.)
The object of the present invention is to provide an optical means for obtaining high contrast by photoelectrically converting information recorded with a black pencil or the like having spectral characteristics such as 1A using a combination of a tungsten lamp and a CCD.

Describing the structure of the present invention, the present invention is an optical information reading device that reads information by irradiating an information recording sheet with light from a tungsten lamp and making the reflected light enter a CCD image sensor via an imaging lens. A filter plate is movably arranged between the information recording sheet and the imaging lens, and when the filter plate is moved, a heat absorption filter and a neutral density filter arranged in parallel on the filter plate are removed. Either one of them is located on the optical path connecting the information reading point of the information recording sheet and the reading optical system, and when the heat absorption filter is located on the optical path, it drops a red color. It is possible to read information recorded on the out-color information recording sheet in black color with spectral reflection characteristics as shown by a black ballpoint pen or black pencil.On the other hand, when a neutral density filter is located on the optical path, This is an optical information reading device that makes it possible to read information recorded in black with spectral reflection characteristics as shown by a black pencil on an information recording sheet that uses a color other than red as a dropout color.

The present invention will be explained below by way of examples with reference to the drawings.

FIG. 5 shows a perspective view of an embodiment of the apparatus, which is a target part of the present invention, and FIG. 4 shows the spectral sensitivity characteristics of each part and the overall spectral sensitivity of the apparatus shown in FIG.

In FIG. 5 showing an embodiment of the present invention, 2
1 is a heat absorption filter (for example, HA-30) having the spectral characteristics shown in FIG. 4 21A, and 22 is FIG.
A neutral density filter (for example, ND-25) having spectral characteristics A is fixed on the same plate 23 and placed in front of the imaging lens 12. 13 indicates a CCD. The plate 23 is movable in the left-right direction as shown by an arrow 40, and is stopped at a position where the center of one of the plates 21 and 22 substantially coincides with the optical axis 50. Now considering the case where the heat absorption filter 21 is set on the optical axis 50, the overall spectral sensitivity characteristic of this system is as shown in FIG. 4 300A,
It forms a gentle mountain shape with a peak around 680mμ. Therefore, high contrast can be obtained not only for a black pencil having spectral characteristics as shown in FIG. 3 201A, but also for a black ballpoint pen having spectral characteristics as shown in FIG. 3 200A.
The red color can be used as a dropout color because it has a low contrast with the red color of μ to 700 μm.

Next, neutral density filter 22
is set on the optical axis 50, since the filter 22 has the characteristics as shown in FIG. 4, 22A, the overall spectral sensitivity characteristic as a system is as shown in FIG.
It becomes the same as 0A.

If the filter 21 or 22 is applied here, the amount of light incident on the CCD 13 will be reduced compared to the case without the filter, but the magnitude of the photoelectric conversion output of the reflected light from the blank area on the information recording sheet will be , a neutral density filter 22 is used that is the same no matter which one of the filters 22 is applied.

For optical systems having spectral characteristics as shown in FIG. 2 100A, there are currently many dropout colors available in addition to red colors.

Therefore, according to the present invention, by setting the heat absorption filter 21 shown in FIG. Information recorded in black, which has spectral characteristics, can be photoelectrically converted with high contrast, and by setting the neutral density filter 22 on the optical axis, information can be recorded using dropout colors other than red. Even information recorded in black, which has spectral characteristics similar to that of a pencil, on a sheet (for example, unified transmission) can be photoelectrically converted with high contrast, so it can quickly and inexpensively meet a variety of needs, including drop-out colors and writing instruments. It can be dealt with and has great practical value.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the optical system of a general optical information reading device, Figure 2 is a tungsten lamp, CCD,
and tungsten lamp - spectral characteristic diagram of CCD optical system, Figure 3 is a spectral reflection characteristic diagram of black ballpoint pen and black pencil, Figure 4 is a heat absorption filter according to the present invention, neutral density filter and tungsten lamp - CCD - heat A spectral characteristic diagram of an absorption filter optical system, FIG. 5 is a perspective view of an apparatus according to an embodiment of the present invention, and FIG. 6 is a drawing showing an example of an information recording sheet. The symbols used in the drawings indicate the following. 10... Information recording sheet, 11... Tungsten lamp, 12... Imaging lens, 13...
CCD, 11A...spectral characteristics of 11, 13A...
13 spectral characteristics, 100A... General spectral characteristics of 11A and 13A, 200A... Spectral reflection characteristics of black ballpoint pen, 201A... Spectral reflection characteristics of black pencil, 21... Heat absorption filter, 22... Neutral density. Filter, 21A...spectral characteristics of 21, 22A...spectral characteristics of 22, 300A
...Comprehensive spectral characteristics of 21A and 100A, 23...
Filter plate, 40...23 movement direction, 5
0...Optical axis, 30...Blank section of information recording sheet,
31...Information recording section, 32...Item or character frame with drop-out color.

Claims (1)

[Claims] 1 The information recording sheet is irradiated with light from a tungsten lamp, and the reflected light is passed through an imaging lens.
In an optical information reading device that reads information by inputting it to a CCD image sensor, a filter plate is movably arranged between an information recording sheet and an imaging lens, and when the filter plate is moved,
Either one of the heat absorption filter and the neutral density filter arranged in parallel on the filter plate is positioned on the optical path connecting the information reading point of the information recording sheet and the reading optical system. , the relative specific energy in the overall spectral sensitivity characteristics of the spectral characteristics of the heat absorption filter, the tungsten lamp, and the sensor reaches a peak near the wavelength of 680 mμ, and also reaches a peak in the near-infrared wavelength region (black ballpoint pen). 1. An optical information reading device characterized in that the spectral characteristics of the heat absorption filter, the tungsten lamp, and the sensor are selected so that the spectral reflectance decreases rapidly in a wavelength range where the spectral reflectance increases.