JP7041539B2 - The light receiving output correction method and light receiving output correction system of the optical line sensor unit, and the optical line sensor unit used for this. - Google Patents

Description

The present invention relates to a light receiving output correction method and a light receiving output correction system of an optical line sensor unit that reads paper sheets such as banknotes and securities, and an optical line sensor unit used thereof, in particular, color reproduction of paper sheets. It is about.

Some optical line sensor units that read paper leaves can acquire color images of paper leaves using a monochromatic LED light source or a white LED light source of each RGB color. As the white LED light source, a combination of an ultraviolet LED and a phosphor, a combination of a visible light LED such as purple or blue and a phosphor, and the like are known (see, for example, Patent Document 1 below).

When a monochromatic LED light source of each RGB color is used, conventionally, a color image is acquired by sequentially (independently) lighting each monochromatic LED light source. In recent years, there has been a demand for faster reading speed of paper sheets, and by lighting each monochromatic LED light source at the same time and providing a color filter on the light receiving part side, it is possible to read at three times the speed of the conventional one. Has been proposed. Similarly, in a configuration using a white LED light source, it is possible to increase the reading speed of paper sheets.

Japanese Unexamined Patent Publication No. 2014-53882

However, the conventional method as described above has a problem in terms of color reproduction. Specifically, in general electronic devices such as displays and printers, an international standard for RGB color space called sRGB, which is defined by the International Electrotechnical Commission (IEC), is adopted. By performing color adjustment according to this sRGB, it is possible to reduce the difference in color between input and output. It is preferable to use sRGB in the optical line sensor unit as well, but there is a problem that there is no light source that can faithfully reproduce the color gamut of sRGB, or when the RGB monochromatic LED light source is turned on at the same time, or a phosphor. Method There is a problem that the color gamut of sRGB is not satisfied when only the white LED light source is turned on, and further, for a considerable variety of paper sheets, the color of sRGB is within the color gamut of sRGB. There are many paper leaves that do not fit in the gamut, and the problem that the paper leaves are the main paper leaves has also emerged.

FIG. 8 is a diagram showing an emission spectrum when a single color LED light source of each RGB color is individually turned on. As described above, the peak wavelength of the emission spectrum corresponding to R (red) is about 650 nm, the peak wavelength of the emission spectrum corresponding to G (green) is about 520 nm, and the peak wavelength of the emission spectrum corresponding to B (blue) is about. It is 460 nm.

FIG. 9 is a diagram showing an emission spectrum when monochromatic LED light sources of each RGB color are turned on at the same time.
However, in this way, when the monochromatic LED light sources of each RGB color are turned on at the same time, the three peaks having peak wavelengths of about 650 nm, about 520 nm, and about 460 nm are the same as when each monochromatic LED light source is turned on individually. Appears.

In the color gamut of sRGB, the main wavelength of the emission spectrum corresponding to G (green) is about 550 nm. Therefore, as described above, there is a large difference from the peak wavelength (about 520 nm) of the emission spectrum corresponding to G (green) when the monochromatic LED light sources of each RGB color are turned on at the same time, and the color gamut of sRGB is faithfully reproduced. Can't.

FIG. 10 is an xy chromaticity diagram showing the color gamut when the monochromatic LED light sources of each RGB color are turned on at the same time in comparison with the color gamut of sRGB. The color gamut of sRGB is shown by a solid line, and the color gamut when a single color LED light source of each RGB color is turned on at the same time and the RGB color separation filter, the spectral sensitivity of the RGB sensor and other spectral characteristics are taken into consideration is shown by a dotted line. .. Here, as the RGB color separation filter, a filter having a large crosstalk was selected. The solid line in FIG. 10 is the sRGB color gamut, and the dotted line is the color reproduction range when the RGB single-color LED light source is turned on at the same time.

As described above, the color gamut when the monochromatic LED light sources of each RGB color are turned on at the same time is significantly different from the color gamut of sRGB. Therefore, it is conceivable to approach the color gamut of sRGB by adjusting the spectral intensity of each color of RGB, but there is a limit to this, and it is difficult to approach the color gamut of sRGB.

FIG. 11 is a diagram showing an emission spectrum when the white LED light source is turned on. As described above, when the white LED light source is turned on, a sharp emission spectrum having a peak wavelength of about 460 nm and a broad emission spectrum having a peak wavelength of about 550 nm appear.

The peak wavelength (about 550 nm) of the broad emission spectrum is a preferable wavelength from the viewpoint of reproducing the color gamut of sRGB, but the color gamut of sRGB cannot be faithfully reproduced. It is possible to adjust the intensity of each peak as shown by the broken line in FIG. 11 by changing the amount of the phosphor in the white LED light source, but it is still difficult to match with the color gamut of sRGB. FIG. 12 shows a comparison of the color gamut of the white LED light source with the sRGB color gamut. The solid line in FIG. 12 is the sRGB color gamut, and the dotted line is the color reproduction range of the white LED light source.

It has been found that it is possible to match the color gamut of sRGB by combining the above-mentioned phosphor-type white LED light source and the RGB monochromatic LED light source, and the white LED light source and the RGB monochromatic LED light source are used. The color gamut when the lights are turned on at the same time is compared with the color gamut of sRGB, and the results are shown in FIGS. 13A and 13B. FIG. 13A is a composite spectrum when a white LED light source and a monochromatic RGB LED light source are turned on at the same time. FIG. 13B compares the color gamut at that time with the color gamut of sRGB.

As described above, the inventor of the present application has studied color matching to the sRGB region for paper leaves, but for some types of paper leaves, although the saturation is low, the color gamut of sRGB is the intermediate color. It has been found that there are more than the above, and it has been newly found that a wider color gamut such as NTSC color gamut and Adobe (registered trademark) RGB color gamut is required.

The present invention proposes "improvement of color reproduction by expanding the color reproduction range", not from the viewpoint of "improvement of color reproduction by color matching". As a result, it is expected that the reading accuracy of the paper sheets of neutral color will be improved, and as a result, the authenticity discrimination of the paper sheets will be more accurate.

Furthermore, as seen in printing equipment, there is a method of expanding the color reproduction range using multicolor ink such as 6 colors using complementary colors, but if this method is applied to the color mixing method, paper sheets Since the optical line sensor unit for discrimination uses not only a visible light source but also an ultraviolet light source and an infrared light source, the number of light sources increases, the substrate on which the light source is placed becomes large, and the dimensions of the light input portion of the light guide body are increased. As a result, the overall size of the optical line sensor unit becomes large. Therefore, it goes against the downsizing which is the trend of the market, so it is preferable to suppress the light source to 4 colors or less first. Further, if a color gamut of NTSC color gamut or Adobe (registered trademark) RGB color gamut or more can be realized, a light source having three or less colors is more preferable. Further, considering the ease of control of the light source over time, a high-speed phosphor-type white LED light source is more preferable.

As described above, in the side light system in which the LED is arranged at the end of the light guide, it is preferable to use a three-color monochromatic LED light source in order to satisfy the downsizing requirement, and further, the white color of the phosphor system. Although an LED light source is more preferable, in a direct type LED arrangement, there is a possibility that downsizing requirements can be satisfied even in an LED arrangement having more than four colors if devised. In addition, it goes without saying that even in the side light method, if size restrictions are allowed, a number of light sources exceeding four colors can be used.

Examples of paper leaves exceeding the sRGB color gamut are shown in FIGS. 14A to 14C. A commercially available color chromaticity meter was used for the measurement.
FIG. 14A shows an example in which the cyan region and the yellow region extend beyond the sRGB region. FIG. 14B shows an example in which the green region extends beyond the sRGB region. FIG. 14C shows an example in which the cyan region extends beyond the sRGB region.
The broken lines in FIGS. 14A to 14C indicate the color gamut of NTSC, the alternate long and short dash line indicates the color gamut of Adobe (registered trademark) RGB, and the solid line indicates the color gamut of sRGB. Both paper sheets are included in the color gamut of NTSC and Adobe® RGB.

As described above, some types of paper leaves require a wider color reproduction range than the sRGB range. That is, a color gamut equal to or larger than the NTSC color gamut, which is wider than the sRGB color gamut, is required.

As described above, when the monochromatic RGB LED light sources were turned on in sequence, they were satisfied with the color reproduction range exceeding the NTSC color gamut and the Adobe (registered trademark) RGB color gamut. A high-speed white LED light source of a method of simultaneously lighting an RGB single-color LED light source or a phosphor type is required. However, when the RGB monochromatic LED light source is turned on at the same time, the color reproduction range of the phosphor-type white LED light source is extremely narrow, and even the sRGB color gamut is not satisfied, and in some paper sheets, the sRGB color gamut. Therefore, it is necessary to develop a new method for realizing a color gamut equivalent to the case where the RGB monochromatic LED light sources are sequentially turned on.

FIG. 15 shows a color reproduction range of a method in which RGB monochromatic LED light sources are sequentially turned on. It has been confirmed that the color reproduction range of the method of sequentially lighting the RGB single-color LED light source is 120% or more of the NTSC ratio. The same applies to the Adobe® RGB color gamut. The broken line in FIG. 15 indicates the color gamut of NTSC, the one-point chain line indicates the color gamut of RGB (registered trademark), the fine solid line indicates the color gamut of sRGB, and the thick solid line indicates the RGB monochromatic LED light source in sequence. Indicates the color gamut of.

By the way, in the printing field, it has a color reproduction range exceeding the sRGB color gamut. FIG. 16 shows the color reproduction range of Japan Color (registered trademark) 2001 with a dotted line. The Japan Color (registered trademark) 2001 color reproduction range far exceeds the sRGB color gamut, and satisfies the color gamut such as the NTSC color gamut and the Adobe (registered trademark) RGB color gamut like the above-mentioned certain types of paper leaves. It is necessary to acquire the color gamut to be used, otherwise the color reproduction will be inaccurate and the authenticity judgment will be inaccurate in the color gamut of a certain neutral color.

Further, FIGS. 17A to 17C show a comparison between the color reproduction range of the certain type of paper leaf and Japan Color (registered trademark) 2001. The color gamut of certain paper leaves mentioned above is also included in Japan Color® 2001. That is, if a color reproduction range including Japan Color (registered trademark) 2001 can be realized, the reading accuracy of almost all paper sheets will be improved, and the authenticity determination will be more accurate.

The present invention has been made in view of the above circumstances, and even when the base of the transmission spectrum of the RGB color separation filter is poorly cut and the crosstalk between RGB is large, the NTSC exceeds the color gamut of sRGB. Provided are a line light source that can satisfy the above color gamut, is inexpensive, and has a processing speed higher than that of a method of sequentially lighting a monochromatic LED light source, and an optical line sensor unit equipped with the line light source. The purpose is.

The main line light source according to the present invention is a line light source used as an illumination light source of an optical line sensor unit for reading paper sheets, and includes a white LED light source or a plurality of monochromatic LED light sources having three or more colors. The white LED light source generates white light by fluorescing a phosphor. The plurality of monochromatic LED light sources generate three or more monochromatic lights having peak wavelengths of different emission spectra.
The line light source illuminates the paper sheets by lighting the white LED light source or simultaneously lighting the plurality of monochromatic LED light sources. The purpose of lighting the plurality of monochromatic LED light sources at the same time is to increase the speed. However, as described above, the color gamut becomes very narrow as it is, and even the color gamut of sRGB is not satisfied, and it goes without saying that the color gamut of NTSC and Adobe (registered trademark) RGB is not satisfied. FIG. 18 shows a comparison of the color reproduction range of the RGB single-color LED light source when they are turned on at the same time, the color reproduction range of the phosphor-type white LED light source, and the color reproduction range when the RGB single-color LEDs are turned on sequentially (independently), including various color gamuts. show. The broken line in FIG. 18 indicates the color gamut of NTSC, the one-point chain line indicates the color gamut of Adobe (registered trademark) RGB, the dotted line indicates the color gamut of the white LED light source, the fine solid line indicates the color gamut of sRGB, and the thick solid line. Indicates the color gamut of the method of sequentially lighting the RGB monochromatic LED light source, and the two-point chain line indicates the color gamut of the method of lighting the RGB single color LED light source at the same time.

Therefore, for example, a reference optical line sensor unit is set in advance, and for the optical line sensor unit, three-color RGB single-color LED light sources are sequentially (independent) with respect to a reference color chart such as a Macbeth chart. ) Obtain the light receiving sensor output corresponding to each color when it is lit. Alternatively, the light receiving sensor output corresponding to each color when the RGV (purple) LED light source or the RY (yellow) GB monochromatic LED is sequentially (independently) turned on may be obtained. Alternatively, a combination of an RGB monochromatic LED light source and a white LED light source, or a combination of an RGV monochromatic LED light source and a white LED light source may be combined with a narrow band optical filter capable of switching between three or four colors. The point is that, first, the reference three-color or four-color light is sequentially turned on to obtain the RGB light-receiving sensor output having each RGB optical filter, or the RYGB light-receiving sensor output having the RYGB optical filter. When the light received by the light receiving sensor passes through the RGB color separation filter and the RYGB filter of the light receiving sensor, a signal without a crosstalk component is obtained. However, it is not limited to three colors or four colors, and it is sufficient that at least three colors or more of colored light can be emitted.

Next, when the RGB monochromatic LED light source is turned on at the same time, the RGV monochromatic LED light source is turned on at the same time, or the white LED light source is turned on, the light receiving sensor is transmitted through the RGB color separation filter of the light receiving sensor. When the light source sensor output corresponding to each RGB obtained by the light reaching the The output of the light receiving sensor obtained by the light emitted is obtained. When the number of colors exceeds four, the number of light receiving sensor outputs corresponding to the colored light may be obtained.
Further, instead of lighting the RGB single color LED light source at the same time, the RGB single color LED light source having a good color reproduction range and the white LED light source may be combined and turned on at the same time, and the RGV single color LED light source and the white LED light source may be turned on at the same time. It may be turned on at the same time by the combination of.

In the light receiving output correction system according to the present invention, two optical line sensor units (first optical line sensor unit and second optical line sensor unit) are used, and one optical line sensor unit (first optical line sensor unit) is used. Based on the light receiving output acquired in use, the light receiving output of the other optical line sensor unit (second optical line sensor unit) is corrected.

As described above, the first optical line sensor unit (reference optical line sensor unit) includes a first light source unit (for example, a three-color RGB single-color LED light source) capable of emitting at least three colors of colored light. Be prepared. Further, the first optical line sensor unit includes a first light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light from the first light source unit. The first optical line sensor unit emits the colored light independently so that the three or more colored lights are not mixed, or has a narrow band so that the spectrum of an arbitrary colored light is not mixed with the spectrum of another colored light. The first reference light receiving output of each color is acquired by emitting light in a spectrum and receiving the reflected light or transmitted light from a predetermined reference color chart by the first light receiving unit.

On the other hand, the second optical line sensor unit includes a second light source unit capable of emitting at least three colors of colored light or white light. Further, the second optical line sensor unit includes a second light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light or white light from the second light source unit. The second optical line sensor unit simultaneously emits three or more colors of light, or emits the white light, and receives the reflected light or the transmitted light from the reference color chart at the second light receiving unit. As a result, the second reference light receiving output of each color is acquired.

The color light of three or more colors may be the color light emitted by the LED, the color light emitted by the LD, or the color light obtained by mixing the color light emitted by the LED and the color light emitted by the LD. The white light may be emitted by a blue or purple LED and a phosphor.
When the three or more color lights are emitted at the same time, the RGB 3-color LED is turned on at the same time, the RGV 3-color LED is turned on at the same time, the light source in which the three-color LED and the white LED are mixed is turned on at the same time, or RGB3. The color LDs are turned on at the same time, the RGV three-color LDs are turned on at the same time, the light source that is a mixture of the three-color LD and the white LED is turned on at the same time, or the light source that is a mixture of the LED, the LD and the white LED is turned on at the same time. You may.

In the following, an example in the case of a three-color LED light source will be described in detail.

There are many devices that use RGB color separation color filters in optical run sensor units for paper sheets, flatbed scanners, digital cameras, cameras for smartphones, etc., but all of them are more or less to RGB colors. Has a crosstalk component of.

That is, the R light receiving sensor output includes the R region component of the emission spectrum of the blue LED light source and the green LED light source, and similarly, the G light receiving sensor output includes the G region component of the emission spectrum of the red LED light source and the blue LED light source. Is included, and the B light receiving sensor output includes a B region component of the emission spectrum of the red LED light source and the green LED light source.

Alternatively, in order to eliminate the crosstalk component of the RGB color separation filter, a method of narrowing the transmission spectrum of the RGB color separation filter of the light receiving sensor can be considered, but the transmission rate of the RGB color separation filter for each color becomes extremely low. As a result, the amount of transmitted light of the RGB color separation filter decreases, and the output of the RGB sensor becomes extremely small, resulting in deterioration of the signal-to-noise ratio (SNR), which is not realistic. Further, even if the problem of SNR is omitted, the layer structure of the RGB color separation filter becomes complicated and the manufacturing cost increases to each stage, which is also not realistic.
However, it is possible to use a reference optical line sensor unit in which the crosstalk component of the color separation filter is minimized.

Furthermore, in order to improve the SNR, it is necessary to perform multiple sampling, and as a result, the processing speed is lowered. In order to secure SNR while increasing the processing speed, it is important to reduce the number of samplings, and multiple sampling should be avoided in the optical line sensor unit for paper sheets.

That is, in the case of having a crosstalk component, in order to maintain the output of the RGB light receiving sensor and to extremely reduce the crosstalk component, it should be aimed at developing means other than those described above.

Even if the RGB color separation filter causes crosstalk, if the crosstalk component can be extremely reduced by another means, the color reproduction range equivalent to the case where the RGB monochromatic LED light sources are sequentially (independently) turned on is the same color reproduction range. Wide RGB light receiving sensor output can be obtained. In the following, the inventor of the present application will describe in detail the above-mentioned alternative means.

Specifically, when the first reference light receiving output is represented by a linear function using a coefficient matrix by the second reference light receiving output, the matrix element of the coefficient matrix is calculated by the least squares method. Then, the second optical line sensor unit simultaneously emits the three or more colored lights, or the white light is emitted, and the reflected light or the transmitted light from the object is received by the second light receiving unit. The light receiving output of each color is acquired, and the light receiving output of each color is corrected by using the inverse matrix of the coefficient matrix calculated based on the matrix elements of the coefficient matrix. The inverse matrix of the matrix elements of the coefficient matrix is stored in the storage unit of the second optical line sensor unit. When the first reference light receiving output is represented by a piecewise linear function by the second reference light receiving output, the inverse matrix of the matrix elements of the coefficient matrix is stored in the storage unit for each section.

（式１）においては、Ｇn（Ｒ）、Ｇn（Ｇ）、Ｇn（Ｂ）並びにＧm（Ｒ）、Ｇm（Ｇ）、Ｇm（Ｂ）は各々のホワイトバランス補正していることが前提となる。 For example, when the outputs of the RGB sensors are set to Gn (R), Gn (G), and Gn (B) when the RGB monochromatic LEDs are turned on sequentially (independently) for an arbitrary medium, and when the RGB monochromatic LEDs are turned on at the same time, Alternatively, assuming that the sensor outputs when the white LED is lit are Gm (R), Gm (G), and Gm (B), if a linear relationship holds for each parameter, it is expressed by the relationship (Equation 1). The linear relationship is based on the premise that there are almost no highlights or underexposed images in paper leaves.
If it becomes necessary to consider non-linearity even in paper sheets, a means such as approximation by a piecewise linear function may be used. In that case, a lookup table may be created in which the matrix elements corresponding to the output values of each RGB light receiving sensor are used and the matrix elements are assigned to any RGB light receiving sensor outputs. For that purpose, a large number of relationships between Gn (R), Gn (G) and Gm (R), Gm (G), and Gm (B) are obtained for (Equation 1) in each RGB light receiving sensor output. For example, there are 27 ways to obtain the relationship between Gn (R), Gn (G) and Gm (R), Gm (G), and Gm (B) for three levels of gradation, and 64 ways for four levels. In the case of 5 stages, 125 combinations may be obtained. That is, (Equation 1) becomes 27, 64, and 125 equations.

In (Equation 1), it is premised that Gn (R), Gn (G), Gn (B) and Gm (R), Gm (G), and Gm (B) are each white balance corrected. ..

但し、ｋ＞９である。
例えば、マクベスチャートを用いる場合は、通常２４色あるので、各ＲＧＢセンサ出力について２４個の方程式（ＲＧＢ各色では、３×２４＝７２個の方程式）が得られ、最小二乗法により、行列要素を求めることが出来る。 Next, the relationship for each color when the reference color chart is read is expressed by (Equation 2) as the suffix "k".

However, k> 9.
For example, when using a Macbeth chart, since there are usually 24 colors, 24 equations (3 × 24 = 72 equations for each RGB color) can be obtained for each RGB sensor output, and the matrix elements can be obtained by the least squares method. You can ask.

The 3 × 3 matrix element obtained from (Equation 2) represents the relationship between the case with crosstalk and the case without crosstalk, and if the inverse matrix of (Equation 2) is obtained as shown in (Equation 3), It is possible to obtain the RGB light receiving sensor output when the white LED light source is turned on, or when the RGB light receiving sensor output is turned on sequentially (independently) from the RGB light receiving sensor output when the RGB single color LED light source is turned on at the same time. As a result, a wide color reproduction range equivalent to that when the RGB monochromatic LEDs are sequentially (independently) lit can be obtained. The inverse matrix of (Equation 2) is shown in (Equation 3).

However, it is not always necessary to use the Macbeth chart, and any other chart may be used.
For example, various color samples such as a standard color chart of 16 colors and a multicolored RAL basic color may be used. You may also use your own color chart using origami, which is rich in neutral colors.

According to such a method, the crosstalk component of the RGB color separation filter generated when an inexpensive RGB color separation filter is used can be extremely reduced.
Furthermore, if the desired color reproduction range is obtained as "RGB light receiving sensor output by color chart of another standard RGB light source other than the reference LED light source", it is extremely close to the color reproduction range. You can get a color reproduction range.

Further, when a four-color light source is used, the matrix element of (Equation 2) is only a 4 × 4 matrix element, and an example of a case where a Y (yellow) light source is added to (Equation 4) is exemplified. do. Even if the number of light sources increases, a matrix element or a sensor output corresponding to the color light of the light source may be added.

ここで、p＝ｋである。 Further, a general conversion formula corresponding to the number of color separation parameters is shown in (Equation 5).

Here, p = k.

From the above, in order to realize the desired color reproduction range, the main wavelength of the light source is determined in consideration of plotting each point of the color reproduction range on the extension line from the white point to the main wavelength, and the light source thereof. (For example, RGB LED light source) is turned on sequentially (independently), white balance is achieved, the reference color chart is illuminated, each RGB light receiving sensor output is obtained, and the reference when the single color RGB LED light source is turned on at the same time. Obtain the output of each RGB light receiving sensor for the color chart, or obtain the output of each RGB light receiving sensor for the reference color chart when the phosphor-type white LED light source is turned on, or obtain the output of each RGB light receiving sensor for the reference color chart, or combine the monochromatic RGB LED light source and the white LED light source at the same time. If you turn it on, illuminate the reference color chart, obtain the output of each RGB light receiving sensor, and find the relationship between when it is turned on sequentially (independently) and when it is turned on at the same time, use (Equation 3) or (Equation 4) to determine RGB. Even when the color separation filter has crosstalk, it is possible to widen the color reproduction range to each stage, and it is possible to accurately read the abundant neutral colors of paper leaves, and as a result, paper leaves. The authenticity judgment of is also accurate.

In the white LED light source used in the present invention, it is preferable that the time for the output to rise from 10% to 90% and the time for the output to fall from 90% to 10% are 2 μs or less, respectively.

According to such a configuration, by using a highly responsive white LED light source, paper leaves can be discriminated at high speed and accurately.

The fluorescent substance is preferably a YAG fluorescent substance.

According to the above method, by simultaneously lighting a white LED light source using a highly responsive YAG phosphor or an RGB monochromatic LED light source, paper sheets can be read at higher speed and with higher accuracy. Furthermore, in the combination of a white LED using a monochromatic LED light source of four or more colors or a phosphor, a light source, and a monochromatic LED light source, paper sheets can be read more accurately.

In the present invention, as described above, a method has been mainly proposed in which a reference light source is set and when the light source is turned on at the same time, the color reproduction range of the reference light source is extremely close to the reference light source. After acquiring the data corresponding to each color light by the ideal crosstalk-free (extremely few) RGB color separation filter and confirming the color reproduction range, the matrix elements in (Equation 1) to (Equation 5) are selected. It can be applied even when the light source to be obtained and actually used is turned on, as in the case of the reference light source. For example, RGB color light in which a monochromatic RGB LED light source and a white LED light source are combined with an RGB color separation filter having a sharp transmission spectrum and no crosstalk may be turned on sequentially (independently), and the sensor output for a reference color chart may be used. ..

The point is that there is only a difference in how to make the standard RGB light source.

When applying the present invention to an optical line sensor unit, for example, in the case of RGB3 colors, a reference optical line sensor unit for sequentially lighting the optical line sensor units is provided in advance, and the reference is provided by independent color light. RGB light receiving sensor outputs Gn (R) _k, Gn (G) _k, Gn (B) _k for the color chart are obtained, or simultaneous lighting without crosstalk provided with another means for maintaining SNR such as multiple sampling. The RGB light receiving sensor outputs Gn (R) _k, Gn (G) _k, and Gn (B) _k for the reference color chart are obtained from the reference optical line sensor unit (in this case, since it is not a product, the reading speed is adjusted. It is not necessary to set a limit), and then the RGB light receiving sensor outputs Gm (R) _k, Gm (G) _k, Gm (B) _k for the reference color chart for each optical line sensor unit that lights up at the same time, which is the actual product. If the correction is made according to (Equation 3), even when the optical line sensor units are turned on at the same time, a color reproduction range extremely close to that of the reference optical line sensor unit in which the optical line sensor units are sequentially turned on can be realized. (Equation 4) and (Equation 5) may be applied to the above-mentioned methods for light sources having four or more colors.

Programmable logic such as FPGA (field-programmable gate array) equipped with a rewritable storage device such as a flash memory for the correction matrix of (Equation 3), (Equation 4), or more generally (Equation 5). If the device is built in as an arithmetic circuit with a fixed coefficient, it can be used for all manufactured products. If the production is stable, the correction with the reference color chart for each optical line sensor unit is not always necessary, and the representative manufactured product is corrected using the reference color chart for each production period and each lot. There are options such as using the same matrix elements for products in the same lot. Alternatively, depending on the needs, the color reproduction range may be changed by appropriately changing the matrix elements based on the conversion formulas such as (Equation 3) and (Equation 4). It is possible. In that case, the matrix element of the FPGA built-in memory may be rewritten. Furthermore, the color reproduction range can be changed by changing the reference color chart. In that case, the reference RGB monochromatic light source is turned on sequentially (independently), and Gn (R) _k, Gn (G) _k, Gn (B) _k are obtained by the RGB light receiving sensor, or the light source ( Gn (R) _k, Gn (G) _k, Gn (B) _k were sequentially obtained from the RGB light receiving sensor for RGB color light of LED or LD (laser diode), and obtained when the RGB light source was turned on at the same time. Gm (R) _k, Gm (G) _k, and Gm (B) _k may be converted by (Equation 3).

Alternatively, Gn (R) _k, Gn (G) _k, and Gn (B) _k are obtained with an RGB light receiving sensor for several types of reference color charts having different color gamuts, and an RGB light source using the same reference color chart is used. Gm (R) _k, Gm (G) _k, Gm (B) _k obtained when the lights are turned on at the same time are obtained, and conversion tables for different reference color charts are provided. It may be appropriately applied to different paper leaves and the like.

The present invention relates to a side light single-sided incident type, a side light double-sided incident type, a direct type, a direct type and a side light type (single-sided incident) mixed method, a direct light type and a side light type (both-sided incident) mixed method, and the like. It can be applied to optical line sensor units.

The side light one-sided incident type optical line sensor unit includes a light guide body, a light diffusion pattern, and a light source. The light guide has a long shape, and an exit surface is formed along the longitudinal direction. The light diffusion pattern is provided along the longitudinal direction of the light guide body, diffuses the light incident on the inside of the light guide body, and emits the light from the emission surface. The light source faces one end face of the light guide in the longitudinal direction, and any colored light is incident on the inside of the light guide from the one end face. The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region. The second light source unit faces the one end face in the longitudinal direction of the light guide, and emits colored light different from the light source into the inside of the light source from the one end face.

The side light double-sided incident type optical line sensor unit includes a light guide body, a light diffusion pattern, and a light source. The light guide has a long shape, and an exit surface is formed along the longitudinal direction. The light diffusion pattern is provided along the longitudinal direction of the light guide body, diffuses the light incident on the inside of the light guide body, and emits the light from the emission surface. The light source faces one end face of the light guide in the longitudinal direction, and any colored light is incident on the inside of the light guide from the one end face. The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region. The second light source unit faces the other end face in the longitudinal direction of the light guide, and incidents a color light different from that of the light source into the inside of the light source from the other end face.

The direct type optical line sensor unit includes a light guide body and a light source. The light guide has a long shape, and an exit surface is formed along the longitudinal direction. The light sources are provided side by side along the longitudinal direction of the light guide body, and any colored light is incident on the inside of the light guide body. The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region. The second light source unit is provided in a different arrangement from the light source along the longitudinal direction of the light guide body.

The direct type and side light type (one-sided incident) mixed type optical line sensor unit includes a light guide body and a light source. The light guide has a long shape, and an exit surface is formed along the longitudinal direction. The light source faces one end face of the light guide in the longitudinal direction, and any colored light is incident on the inside of the light guide from the one end face. The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region. The second light source unit is provided in a different arrangement from the light source along the longitudinal direction of the light guide body.

The direct type and side light type (both sides incident) mixed type optical line sensor unit includes a light guide body, a light source, and another light source. The light guide has a long shape, and an exit surface is formed along the longitudinal direction. The light source faces one end face of the light guide in the longitudinal direction, and any colored light is incident on the inside of the light guide from the one end face. The other light source faces the other end face in the longitudinal direction of the light guide body, and a color light different from that of the light source is incident on the inside of the light guide body from the other end face. Each of the light sources is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region. The second light source unit is provided in a different arrangement from the light source along the longitudinal direction of the light guide body.

According to the present invention, by illuminating the paper leaves by simultaneously lighting the white LED light source and a plurality of monochromatic LED light sources, it is possible to accurately read the color reproduction range of the paper leaves beyond the color range of sRGB. As a result, the authenticity judgment of paper leaves becomes accurate. At the same time, even when the ink of paper leaves is advanced in the future and the color reproduction of neutral colors is enriched in order to counter counterfeit banknotes, if the present invention is used, it becomes possible to read accurately and the authenticity can be determined. It can be carried out accurately.

It is sectional drawing which shows schematic the structure of the optical line sensor unit in embodiment of this invention. It is sectional drawing which shows the additional structure of an optical line sensor unit schematicly. It is a perspective view of a line light source. It is an exploded perspective view which shows each component of a line light source. It is a side view of a line light source. It is a schematic diagram which shows the element arrangement of a light receiving part. It is a figure which shows the arrangement example of the light receiving element and each color filter in a light receiving part. It is a figure which showed the emission spectrum when the monochromatic LED light source of each RGB color is turned on individually. It is a figure which showed the emission spectrum when the monochromatic LED light source of each RGB color is turned on at the same time. FIG. 5 is an xy chromaticity diagram showing a color gamut when a single color LED light source of each RGB color is turned on at the same time in comparison with the color gamut of sRGB. It is a figure which showed the emission spectrum when the white LED light source was turned on. It is a figure which compared the color reproduction area of a white LED light source with sRGB color gamut. It is a figure which showed the composite spectrum when the white LED and the monochromatic RGB LED are turned on at the same time. It is a figure which compared the color gamut of FIG. 13-A with the color gamut of sRGB. It is a figure which showed that the cyan region and the yellow region protrude from the sRGB region. It is a figure which showed that the green area protrudes from the sRGB area. It is a figure which showed that the cyan region protrudes from the sRGB region. It is a figure which showed the color reproduction area when the RGB monochromatic LED is turned on sequentially. It is a figure which showed the color reproduction range of Japan Color (registered trademark) 2001. It is a figure which showed the example which the paper leaf exceeds the sRGB color gamut. It is a figure which showed the example which the paper leaf exceeds the sRGB color gamut. It is a figure which showed the example which the paper leaf exceeds the sRGB color gamut. The figure showing a comparison of the color reproduction range of the RGB single-color LED when they are turned on at the same time, the color reproduction range of the phosphor-type white LED, and the color reproduction range when the RGB single-color LED is turned on sequentially (independently), including various color gamuts. be. It is a figure which compared the chromaticity when the monochromatic RGB LED is lit sequentially (independently) with respect to the reference color chart, and the chromaticity before correction when the monochromatic RGB LED is lit at the same time. It is a figure which compared the chromaticity when the monochromatic RGB LED is lit sequentially (independently) with respect to the reference color chart, and the chromaticity after correction when the monochromatic RGB LED is lit at the same time. It is a figure which compared the chromaticity when the monochromatic RGB LED with respect to a reference color chart is turned on sequentially (independently), and the chromaticity before correction when the white LED is turned on. It is a figure which compared the chromaticity when the monochromatic RGB LED with respect to a reference color chart is turned on sequentially (independently), and the chromaticity before correction when the white LED is turned on. This is the chromaticity of the paper sheets 1 when the monochromatic RGB LEDs are turned on sequentially (independently). This is the chromaticity of the paper sheets 1 when the monochromatic RGB LEDs are turned on at the same time. This is the corrected chromaticity of the paper sheets 1 when the monochromatic RGB LEDs are turned on at the same time. This is the chromaticity of the paper leaf 1 when the white LED is turned on. This is the corrected chromaticity of the paper leaf 1 when the white LED is turned on. This is the chromaticity of the paper sheets 2 when the monochromatic RGB LEDs are turned on sequentially (independently). This is the chromaticity of the paper sheets 2 when the monochromatic RGB LEDs are turned on at the same time. This is the corrected chromaticity of the paper sheets 2 when the monochromatic RGB LEDs are turned on at the same time. This is the chromaticity of the paper sheets 2 when the white LED is turned on. This is the corrected chromaticity of the paper sheets 2 when the white LED is turned on. This is the chromaticity of the paper sheets 3 when the monochromatic RGB LEDs are turned on sequentially (independently). This is the chromaticity of the paper sheets 3 when the monochromatic RGB LEDs are turned on at the same time. This is the corrected chromaticity of the paper sheets 3 when the monochromatic RGB LEDs are turned on at the same time. This is the chromaticity of the paper sheets 3 when the white LED is turned on. This is the corrected chromaticity of the paper sheets 3 when the white LED is turned on.

<Optical line sensor unit>
FIG. 1 is a schematic cross-sectional view showing the configuration of an optical line sensor unit according to an embodiment of the present invention.

This optical line sensor unit includes a housing 16, a line light source 10 for illuminating paper leaves, and a lens for guiding light emitted from the line light source 10 toward the focal plane 20 and reflected by the paper leaves. The array 11 and a light receiving unit 12 mounted on the substrate 13 and receiving the transmitted light guided by the lens array 11 are provided. Paper leaves are transported in one direction x (secondary scanning direction) along the focal plane 20.
These housing 16, the line light source 10, the light receiving unit 12, and the lens array 11 extend in the y direction (main scanning direction), that is, in the direction perpendicular to the paper surface in FIG. 1, and FIG. 1 shows a cross section thereof. ing.

The line light source 10 is a unit that emits light toward the paper leaves on the focal plane 20. The types of emitted light are visible light, white light and ultraviolet light, and infrared light may also be emitted.
This ultraviolet light has a peak wavelength of 300 nm to 400 nm, and infrared light has a peak wavelength of up to 1500 nm.
Of these lights, at least ultraviolet light is emitted so as not to overlap with other lights in time (that is, while being switched in time). Infrared light may be emitted so as to overlap with visible light in time, or may be emitted so as not to overlap with visible light in time.

The light emitted from the line light source 10 passes through the protective glass 14 and is focused on the focal plane 20. The protective glass 14 is not always necessary and can be omitted, but the line light source 10 and the lens array are prevented from scattering and scratching dust during use (during use) (dust such as paper dust generated during transportation of paper leaves). It is desirable to install it to protect 11.
The material of the protective glass 14 may be any material as long as it transmits light emitted from the line light source 10, and may be a transparent resin such as an acrylic resin or a cycloolefin resin. However, in the embodiment of the present invention, it is preferable to use glass such as white plate glass or borosilicate glass that transmits ultraviolet light.

A substrate 5 for fixing a light source unit 3 and a light source unit 4 (see FIGS. 4 and 5) installed at both ends of the line light source 10 is installed facing the bottom surface of the line light source 10. The substrate 5 is a thin insulating plate made of phenol, glass epoxy, or the like, and a wiring pattern made of copper foil is formed on the back surface thereof. The terminals of the light source portions 3 and 4 are inserted into holes formed in various parts of the substrate 5, and the light source portions 3 and 4 are mounted and fixed on the substrate 5 by joining the wiring pattern with solder or the like on the back surface of the substrate. At the same time, power can be supplied from a predetermined drive power source (not shown) to the light source units 3 and 4 through a wiring pattern on the back surface of the substrate to drive and control the light emission.

The lens array 11 is an optical element that forms an image of light reflected by paper sheets on the light receiving unit 12, and a rod lens array such as a selfock lens array (registered trademark: manufactured by Nippon Sheet Glass) can be used. In the embodiment of the present invention, the magnification of the lens array 11 is set to 1 (upright).
It is preferable to provide an ultraviolet light blocking filter 15 at an arbitrary position from the focal plane 20 to the light receiving unit 12 by reflecting or absorbing the ultraviolet light so that the ultraviolet light does not enter the light receiving unit 12. In the embodiment of the present invention, the ultraviolet light blocking filter 15 is attached to the surface of the lens array 11 to have a function of blocking ultraviolet light. As used herein, "blocking light" means reflecting or absorbing light and not transmitting it.

The ultraviolet light blocking filter 15 is not particularly limited, and may be of any material and structure as long as it can prevent ultraviolet light from entering the light receiving unit 12. For example, an ultraviolet light absorbing film in which an organic ultraviolet light absorber is mixed or coated in a transparent film, or a thin film of a metal oxide or a dielectric having different transmittances and refractive indexes such as titanium oxide and silicon oxide is deposited on the glass surface in multiple layers. The interference filter (band pass filter) obtained in the above is preferable.

Although the ultraviolet light blocking filter 15 is attached to the exit surface of the lens array 11, it may be attached to the incident surface or the intermediate portion of the lens array 11 or may be used by directly vapor-depositing or coating it on the inner surface of the protective glass 14. good. In short, it suffices if the ultraviolet light reflected by the paper sheets can be prevented from entering the light receiving unit 12.
The light receiving unit 12 is mounted on the substrate 13 and includes a light receiving element that receives reflected light and reads an image as an electric output by photoelectric conversion. The material and structure of the light receiving element are not particularly specified, and a photodiode or phototransistor using amorphous silicon, crystalline silicon, CdS, CdSe, or the like may be arranged. Further, it may be a CCD (Charge Coupled Device) linear image sensor. Further, as the light receiving unit 12, a so-called multi-chip type linear image sensor in which a plurality of ICs (Integrated Circuits) in which a photodiode, a phototransistor, a drive circuit, and an amplifier circuit are integrated can be arranged can also be used. Further, if necessary, an electric circuit such as a drive circuit or an amplifier circuit, or a connector for taking out a signal to the outside can be mounted on the substrate 13. Further, an A / D converter, various correction circuits, an image processing circuit, a line memory, an I / O control circuit, and the like can be simultaneously mounted on the substrate 13 and taken out as a digital signal.

The above-mentioned optical line sensor unit was a reflection type optical line sensor unit that was emitted from the line light source 10 toward the paper leaves and received the light reflected by the paper leaves. As shown in FIG. A transmissive type in which the line light source 10 is placed at a position opposite to the light receiving unit 12 with the focal plane 20 as a reference, and the light emitted from the line light source 10 toward the paper leaves and transmitted through the paper leaves is received. It may be an optical line sensor unit. In this case, the structure of the line light source 10 itself is not different from that described so far, except that the position of the line light source 10 is below the focal plane 20 only in the arrangement of FIG. Further, both a reflective optical line sensor unit and a transmissive optical line sensor unit may be included.

<Line light source>
FIG. 3 is a perspective view schematically showing the appearance of the line light source 10 in the optical line sensor unit shown in FIG. 1. FIG. 4 is an exploded perspective view of each component of the line light source 10, and FIG. 5 is a side view of the line light source 10. Note that the cover member 2 is not shown in FIG.
The line light source 10 includes a transparent light guide body 1 extending along the longitudinal direction L, a light source unit 3 provided near one end face of the longitudinal direction L, and a light source provided near the other end face of the longitudinal direction L. Light diffusion formed diagonally between the bottom side surface 1a and the left and right side surfaces 1b, the cover member 2 for holding each side surface (bottom side surface 1a and left and right side surfaces 1b, 1c) of the light guide body 1. The light of the light guide body 1 is formed on the pattern forming surface 1g, and the light incident on the end faces 1e and 1f of the light guide body 1 from the light source unit 3 and the light source unit 4 is diffused and refracted to travel through the light guide body 1. It has a light diffusion pattern P for emitting light from the emission side surface 1d. Further, it is preferable to have a second optical filter 6 and a first optical filter 7 formed on the end faces 1e and 1f of the light guide body 1, respectively.

The light guide body 1 may be formed of a highly light-transmitting resin such as acrylic resin or optical glass, but in the embodiment of the present invention, since the light source unit 4 that emits ultraviolet light is used, the light guide body 1 is guided. As the material of the body 1, a fluororesin or a cycloolefin resin having relatively little attenuation to ultraviolet light is preferable.
The light guide body 1 has an elongated columnar shape, and its cross section orthogonal to the longitudinal direction L has substantially the same shape and the same dimensions at any cut end in the longitudinal direction L. Further, the proportion of the light guide body 1, that is, the ratio of the length of the light guide body 1 in the longitudinal direction L to the height H of the cross section orthogonal to the longitudinal direction L is larger than 10, preferably larger than 30. For example, if the length of the light guide body 1 is 200 mm, the height H of the cross section orthogonal to the longitudinal direction L is about 5 mm.

The side surfaces of the light guide body 1 are a light diffusion pattern forming surface 1 g (corresponding to an oblique cut surface of the light guide body 1 in FIG. 4), a bottom side surface 1a, left and right side surfaces 1b, 1c, and a light emission side surface 1d (light guide in FIG. 4). It consists of five sides (corresponding to the upper surface of the body 1). The bottom side surface 1a and the left and right side surfaces 1b and 1c have a planar shape, and the light emitting side surface 1d is formed in an outwardly smooth convex curved shape in order to have a light collecting effect of the lens. However, the light emitting side surface 1d does not necessarily have to be formed in a convex shape, and may have a planar shape. In this case, it is preferable to arrange a lens that collects the light emitted from the light guide body 1 so as to face the light emitting side surface 1d.

The light diffusion pattern P on the light diffusion pattern forming surface 1g maintains a constant width and extends linearly along the longitudinal direction L of the light guide body 1. The dimension of the light diffusion pattern P along the longitudinal direction L is formed to be longer than the reading length of the image sensor (that is, the width of the reading region of the light receiving unit 12).
The light diffusion pattern P is composed of a plurality of V-shaped grooves engraved on the light diffusion pattern forming surface 1g of the light guide body 1. Each of the plurality of V-shaped grooves is formed so as to extend in a direction orthogonal to the longitudinal direction L of the light guide body 1, and has the same length as each other. The plurality of V-shaped grooves may have, for example, an isosceles triangle in cross section.

Due to this light diffusion pattern P, light incident from the end faces 1e and 1f of the light guide body 1 and propagating inside the light guide body 1 in the longitudinal direction L is refracted and diffused, and is substantially uniform along the longitudinal direction L. It is possible to irradiate from the side surface 1d of light emission with brightness. As a result, the light emitted to the paper sheets can be made substantially constant in the entire longitudinal direction L of the light guide body 1, and the uneven illuminance can be eliminated.

The V-shape of the groove of the light diffusion pattern P is an example, and can be arbitrarily changed such as a U-shape instead of the V-shape as long as the uneven illuminance is not noticeable. The width of the light diffusion pattern P does not need to be maintained constant, and the width may change along the longitudinal direction L of the light guide body 1. The depth of the groove and the opening width of the groove can also be changed as appropriate.
The cover member 2 has an elongated shape along the longitudinal direction L of the light guide body 1, and the light diffusion of the light guide body 1 so as to cover the bottom side surface 1a and the left and right side surfaces 1b, 1c of the light guide body 1. It has a bottom surface 2a facing the pattern forming surface 1g, a right side surface 2b facing the right side surface 1b of the light guide body 1, and a left side surface 2c facing the left side surface of the light guide body 1. Since each of these three side surfaces forms a flat surface and a recess having a substantially U-shaped cross section is formed on the inner surface of each of the three inner surfaces, the light guide body 1 can be inserted into the recess. In this covered state, the bottom surface 2a of the cover member 2 is in close contact with the bottom side surface 1a of the light guide body 1, the right side surface 2b of the cover member 2 is in close contact with the right side surface 1b of the light guide body 1, and the left side surface 2c is guided. It is in close contact with the left side surface 1c of the light body 1. Therefore, the cover member 2 can protect the light guide body 1.

The cover member 2 is not limited to a transparent cover, and may be translucent or opaque. For example, the cover member 2 is coated with a molded product of white resin having high reflectance or a white resin thereof in order to reflect the light leaking from the side surface other than the light emitting side surface of the light guide body 1 again into the light guide body 1. It may be a molded product of the resin. Alternatively, the cover member 2 may be formed of a metal body such as stainless steel or aluminum.

The light source unit 3 includes a white LED light source 3W that generates white light (W), a monochromatic LED light source 3R that generates red (R) monochromatic light, and a monochromatic LED light source 3G that generates green (G) monochromatic light. , A monochromatic LED light source 3B for generating blue (B) monochromatic light, and a monochromatic LED light source 3V for generating purple (V) monochromatic light. However, the light source unit 3 may include an infrared light source that generates infrared light. The white LED light source 3W is a light source that generates white light by fluorescing a phosphor. For example, a white LED light source that fluoresces a phosphor to generate white light with a blue or purple LED, or an ultraviolet LED that fluoresces. A white LED light source or the like that fluoresces the body to generate white light is used. The phosphor is mixed with a coating or a sealing agent on the LED element, and by adding the light emission of the phosphor to the light from the LED, it becomes a white LED light source having an output in the entire visible light region.

The white LED light source 3W is preferably highly responsive, for example, the response time from 10% to 90% of the output (relative emission intensity) and the response time from 90% to 10%. It is 2 μs or less, particularly preferably 0.5 μs or less. Since the responsiveness of the white LED light source that fluoresces the phosphor to generate white light is impaired due to the use of the phosphor, it is preferable to adopt a specific phosphor. For example, the LED element (not shown) of the white LED light source 3W is purple or blue, and has a structure in which a phosphor is covered on the element. If a YAG phosphor (YAG: Ce (cerium-doped yttrium oxide, aluminum garnet sintered body)) that emits yellow light is used as the phosphor, a white LED light source 3W having a high response speed can be obtained.

The light source unit 4 is an ultraviolet light source that emits ultraviolet light to the light guide body 1, and an ultraviolet light LED light source having a diameter of 300 nm to 400 nm or the like can be used. An ultraviolet light emitting diode having a peak emission wavelength in the range of 330 nm to 380 nm is preferably used.

Terminals 31 for mounting on the substrate 5 are formed in the light source unit 3 and the light source unit 4, and the terminals 31 are inserted into the substrate 5 and joined by soldering or the like to drive power sources (shown in the figure). Is electrically connected. The drive power source selects the electrode terminal that applies a voltage to the light source unit 3 and the electrode terminal that applies a voltage to the light source unit 4, so that the light source unit 3 and the light source unit 4 are simultaneously or temporally switched to emit light. It has a circuit configuration that can be used. Further, any LED can be selected from a plurality of LEDs built in the light source unit 3 and simultaneously or temporally switched to emit light.

With the above configuration, in a compact configuration, white light and monochromatic light of a plurality of colors can be incident on the light guide body 1 from the end surface 1e where the light source unit 3 is installed, and from the end surface 1f where the light source unit 4 is installed. Ultraviolet light can be incident on the light source 1. As a result, the light emitted from the light source unit 3 or the light emitted from the light source unit 4 can be emitted from the light emitting side surface 1d of the light guide body 1.

Preferably, the end surface 1e on which the light source portion 3 of the light guide body 1 is installed has a second optical filter 6 that transmits visible light of 420 nm or more and blocks ultraviolet light of less than 400 nm by reflecting or absorbing it. It is provided. Further, the end surface 1f on which the light source portion 4 of the light guide body 1 is installed is provided with a first optical filter 7 that transmits ultraviolet light of less than 400 nm and blocks visible light of 420 nm or more by reflecting or absorbing it. ing.

The second optical filter 6 and the first optical filter 7 are not particularly limited, and may be of any material and structure as long as they block the target wavelength range. For example, in the case of an optical filter that reflects light, an interference filter (bandpass filter) obtained by laminating a thin film of a metal oxide or a dielectric having different transmittances and refractive indexes on the glass surface is preferable.
For example, silicon oxide and tantalum pentoxide are used as the interfering filter to reflect, and the desired bandpass filter characteristics are secured by performing multi-layer deposition by adjusting the transmittance, refractive index and film thickness of each. can get. As a matter of course, there is no particular limitation in adoption as long as it is a bandpass filter conventionally produced for ordinary optical-related industries and satisfies the required performance.

When an interference filter is used for the second optical filter 6 and the first optical filter 7, if the target transmission region cannot be adjusted only by the interference filter, a metal or an oxide thereof, a nitride, etc. It is possible to secure desired wavelength characteristics by stacking films using a thin film of fluoride.
If the second optical filter 6 is an optical filter that absorbs ultraviolet light, it may be an ultraviolet light absorbing film in which an organic ultraviolet light absorber is mixed or coated in a transparent film. In addition, for example, silicon oxide and titanium oxide are used as interference filters, and the transmittance, refractive index, and film thickness of each are adjusted to achieve multi-layer deposition, thereby blocking ultraviolet light by both reflecting and absorbing functions. The desired wavelength characteristic may be secured.

If the first optical filter 7 is an optical filter that absorbs visible light, a substance that allows ultraviolet light to pass through and cuts visible light may be added to the film.
The method of installing the second optical filter 6 and the first optical filter 7 on the light guide body 1 is arbitrary, and the end faces 1e and 1f of the light guide body 1 may be coated or coated by coating or vapor deposition. Further, a film-shaped or plate-shaped second optical filter 6 and a first optical filter 7 are prepared and brought into close contact with the end faces 1e and 1f of the light guide body 1, or at a certain distance from the end faces 1e and 1f. It may be attached.
Further, the second optical filter 6 and the first optical filter 7 can be provided not on the end faces 1e and 1f of the light guide body 1 but on the light source units 3 and 4. In this case, the optical filters 6 and 7 may be coated on the light source units 3 and 4 by coating or vapor deposition, or a film-shaped or plate-shaped optical filter 6 and 7 may be prepared and adhered to the light source units 3 and 4. It may be attached by letting it. Alternatively, the second optical filter 6 may be configured by adding a substance that transmits visible light and blocks ultraviolet light to the sealing agent of the light source unit 3. Similarly, the first optical filter 7 may be configured by adding a substance that transmits ultraviolet light and blocks visible light to the sealant of the light source unit 4.

If the first optical filter 7 is an optical filter that transmits ultraviolet light and reflects or absorbs visible light, it has the following advantages. It is assumed that the light source unit 4 employs a mounting substrate such as an aluminum oxide / ceramics sintered body that emits fluorescence in the vicinity of a wavelength of 690 nm when exposed to ultraviolet light. When the ultraviolet light is irradiated from the light source unit 4, it is necessary to prevent the irradiated light from hitting the mounting substrate of the light source unit 4 and being secondarily irradiated with fluorescence near 690 nm to enter the light guide body 1. Therefore, if the first optical filter 7 is designed so as to reflect or absorb visible light so that the second-irradiated fluorescence does not enter the light guide body 1, the light guide body 1 can be used. It is possible to prevent unnecessary emission of fluorescence from the light emitting side surface 1d, and it is possible to improve the contrast of ultraviolet fluorescence of paper leaves. It should be noted that not only the aluminum oxide / ceramics sintered body that fluoresces the ultraviolet light but also the case where the sealing resin fluoresces can prevent the secondary irradiation.

If the second optical filter 6 is an optical filter that transmits visible light and reflects or absorbs ultraviolet light, it has the following advantages. It is assumed that the light source unit 3 employs a mounting substrate such as an aluminum oxide / ceramics sintered body that emits fluorescence in the vicinity of a wavelength of 690 nm when exposed to ultraviolet light. When the ultraviolet light emitted from the light source unit 4 passes through the end surface 1e of the light guide body 1 and hits the light source unit 3, fluorescence near 690 nm is secondarily irradiated from the light source unit 3 and enters the light guide body 1. It will come, so we need to prevent this. Therefore, if the second optical filter 6 is designed to reflect or absorb the ultraviolet light so that the ultraviolet light does not come out from the end surface 1e of the light guide body 1, it does not hit the light source unit 3. .. Therefore, it is possible to prevent unnecessary fluorescence from being emitted from the light emitting side surface 1d of the light guide body 1. As a result, the contrast of ultraviolet fluorescence of paper leaves can be improved.

In the embodiment of the present invention, an optical filter in which the second optical filter 6 transmits visible light and reflects ultraviolet light is preferable, and has the following advantages. Since the amount of ultraviolet light incident on the light guide body 1 from the light source unit 4 and reflected by the second optical filter 6 and returning to the light guide body 1 increases, as a result, the ultraviolet rays from the light emitting side surface 1d of the light guide body 1 The effect of increasing the amount of emitted light can be obtained. In this case, since the second optical filter 6 transmits the visible light emitted from the light source unit 3, it does not prevent the visible light from the light source unit 3 from entering the light guide body 1.

If the first optical filter 7 is an optical filter that transmits ultraviolet light and reflects visible light, it is irradiated from the light source unit 3, incident on the light guide body 1, reflected by the first optical filter 7, and guided. Since the amount of visible light returning to the body 1 increases, as a result, the effect of increasing the amount of visible light emitted from the light emitting side surface 1d of the light guide body 1 can be obtained. Further, since the first optical filter 7 transmits the ultraviolet light emitted from the light source unit 4, the ultraviolet light can be emitted from the light emitting side surface 1d of the light guide body 1.

The ultraviolet light emitted from the light source unit 4 enters the light guide body 1 through the first optical filter 7, is diffused and refracted by the light diffusion pattern forming surface 1g, and is transmitted from the light emission side surface 1d to the focal surface 20. A certain paper leaf (medium) is irradiated. As a result, fluorescence is generated from the paper leaves, and the fluorescent color emission is detected by the light receiving unit 12, so that the paper leaves can be identified using ultraviolet light.
The white light emitted from the white LED light source of the light source unit 3 and the monochromatic light of a plurality of colors emitted from the monochromatic LED light sources 3R, 3G, 3B, and 3V are incident on the light guide body 1 via the second optical filter 6. Then, it is diffused and refracted by the light diffusion pattern forming surface 1g, and is irradiated from the light emission side surface 1d to the paper leaves (medium) on the focal surface 20. This makes it possible to identify paper leaves using visible light.

<Light receiving part>
FIG. 6 is a schematic diagram showing the element arrangement of the light receiving unit 12. The light receiving unit 12 arranges a sensor IC chip that integrates a plurality of light receiving elements (consisting of a photodiode, a phototransistor, etc.) arranged linearly in the y direction, a signal processing unit 21, and a driver 22. Each light receiving element is covered with a color filter, and this is mounted on a substrate. The driver 22 is a circuit portion that creates and supplies a bias current for driving the light receiving element, and the signal processing unit 21 is a circuit portion that reads and processes the photodetection signal of the light receiving element. The type of the light receiving element is not limited, and for example, a silicon PN diode or a PIN diode is used.

By exposing the light receiving elements arranged in a row while the paper leaves move in the x direction (secondary scanning direction), the surface of the paper leaves has a predetermined width along the y direction (main scanning direction). Observation lines can be set. The exposure time (referred to as optical reading time) for reading the line information of paper sheets can be arbitrarily set according to the intensity of the light source, the wavelength sensitivity of the sensor, and the like. For example, the moving speed of paper sheets in the x direction is 1500 to 2000 mm / sec in an ATM or a banknote processor, and if 0.5 to 1.0 ms is adopted as the optical reading time, the moving speed in the x direction of the observation line is adopted. The width is 0.75 to 2 mm.

In the embodiment of the present invention, as shown in FIG. 6, a plurality of, for example, four light receiving elements are linearly formed per pixel of the light receiving unit 12 (a pixel means a spatial unit for reading and processing image data). It is composed side by side. In FIG. 6, of the four light receiving elements, the first light receiving element is covered with a red (R) color filter, the second light receiving element is covered with a green (G) color filter, and the third light receiving element is covered. Is covered with a blue (B) color filter. The fourth light receiving element is covered with a transparent filter (W) or is not covered with each color filter. The color filters (R, G, B) are usually opaque to ultraviolet light having a wavelength of 300 to 400 nm, and have transparency to infrared light having a wavelength of 800 nm or more.
As described above, the light receiving unit 12 is provided with a visible light color filter (R, G, B) in association with each pixel, and the light transmitted through the color filter is incident on each light receiving element. However, the color filter is not limited to three colors for each pixel.
In FIG. 6, only one element is covered with a color filter of the same color, but two or more light receiving elements may be covered with a color filter of the same color.

A transparent (W) filter is a "transparent" filter without any coloring. Alternatively, it may be a light transmission spectrum obtained by superimposing the light transmission spectra of all the color filters. For example, it may be a light transmission spectrum having a contour formed by superimposing the light transmission spectrum of the R filter, the light transmission spectrum of the G filter, and the light transmission spectrum of the B filter. It may have the same light transmittance as the envelope when the envelope is formed by connecting the transmission bands. The material of the optical filter forming such a "transparent filter" is selected from transparent acrylic resin, cycloolefin resin, silicone resin, and fluororesin for organic materials, and silicon nitride and silicon oxide for inorganic materials. It is selected from among.

Each of these color filter materials is also transparent to ultraviolet light of 300 to 400 nm.
As for organic materials, it is not preferable to use a transparent material containing an ultraviolet light absorber used for liquid crystal applications because it is not transparent to ultraviolet light.
As described above, since the light receiving unit 12 is equipped with a plurality of light receiving elements and color filters of each color covering them in one pixel, each of them independently emits light in a desired wavelength region without switching the wavelength of the light source. By lighting a plurality of light emitting elements that can be irradiated at the same time, it is possible to output the color information of paper sheets at one time on one observation line.

The photodetection signal of the light receiving unit 12 having such a configuration is a signal obtained by simultaneously acquiring the light detection signals of each light receiving element, and these are input to the signal processing unit 21. The signal processing unit 21 determines the color information of paper sheets based on the signal intensity of the light receiving element transmitted through the R, G, and B color filters of the light receiving unit 12, and also transmits the transparent (W) filter. Alternatively, the total amount of light entering the pixel is calculated based on the signal intensity that does not pass through each of the color filters. As a result, it is possible to obtain image data based on the accurate light amount of each color signal with the total light amount as the denominator (reference).

However, the element arrangement of the light receiving unit 12 is not limited to the above-mentioned form. For example, as shown in FIG. 7A, the light receiving elements of the light receiving unit 12 are not always arranged in a single row such as RGBWRGBW ..., but may be arranged in two or more rows. good. FIG. 7B shows the light receiving elements arranged in 2 × 2 per pixel, and a transparent (W) filter or each color filter is provided in one corner of one of the two rows (for example, the lower row). An example in which the second light receiving element of nothing is arranged is shown. FIG. 7C shows the light receiving elements arranged in four rows per pixel, and one of the four rows (for example, the lowest row) has no transparent (W) filter or each color filter. An example in which the second light receiving elements of the above are arranged is shown. Even in these cases, the optical signal detected through the transparent (W) filter or the light receiving element without each color filter is recorded in one pixel, and each light receiving element transmitted through each color filter (R, G, B). Signal strength can be detected.
Further, by providing a green (G) color filter instead of the transparent (W) filter, an arrangement such as RGBGRGBG ... may be formed.

As described above, the RGB light receiving sensor output is first obtained by turning on the RGB monochromatic light sources sequentially (independently), and then the RGB monochromatic light sources are turned on at the same time, or the RGB obtained by the phosphor type white LED light source is used. The RGB light receiving sensor output including the crosstalk component of the color separation filter is obtained, and further, the monochromatic RGB light source and the white LED light source are combined and turned on at the same time, and the output from the RGB light receiving sensor is obtained, and the conversion formula ( Using Equations 1) to (Equation 3) and (Equation 4), it is possible to obtain an extremely close RGB light receiving sensor output when the RGB monochromatic light sources without crosstalk components are sequentially (independently) turned on. It was confirmed that the color reproduction range is very close to that when the RGB single-color light sources are turned on sequentially (independently), and a wide color reproduction range can be obtained in each stage. The case where the typical single-color RGB LED light sources in the embodiment are turned on sequentially (independently) is regarded as the reference optical line sensor unit (first optical line sensor unit), and the case where the single-color RGB LED light source on the corrected side is turned on at the same time. Will be exemplified below as the second optical line sensor unit A and the case where the white LED light source is turned on as the second optical line sensor unit B.

The reference optical line sensor unit (first optical line sensor unit) and the corrected optical line sensor unit (second optical line sensor unit A or second optical line sensor unit B) are, for example, FIGS. 1 to 1. Optical line sensor units as shown in FIG. 7 can be used respectively. However, the reference optical line sensor unit (first optical line sensor unit) and the corrected optical line sensor unit (second optical line sensor unit A or second optical line sensor unit B) have different configurations. May have.

The reference optical line sensor unit (first optical line sensor unit) may include a light source unit (first light source unit) capable of emitting at least three colors of colored light. The light source unit may be the same as the light source unit 3 of the above-mentioned optical line sensor unit, but may have a configuration in which the white LED light source 3W in the light source unit 3 is omitted. Further, the light source unit is not limited to a configuration that emits four colored lights of red, green, blue, and purple, and may be capable of emitting at least three colors of colored light. Further, the light source unit is not limited to the LED, and may be configured by other light sources such as LD or a combination thereof, and the combination of each color is also arbitrary. In the reference optical line sensor unit (first optical line sensor unit), the colored light is emitted independently so that the three or more colored lights are not mixed, or the spectrum of an arbitrary colored light is mixed with the spectrum of another colored light. Light is emitted in a narrow-band spectrum so as not to occur. Then, the light is applied to a predetermined reference color chart, and the reflected light or transmitted light from the reference color chart is received by the light receiving unit 12 (first light receiving unit). As a result, the first reference light receiving output of each color is acquired.

On the other hand, the optical line sensor unit (second optical line sensor unit A or second optical line sensor unit B) on the corrected side is a light source unit (second optical line sensor unit A) capable of emitting at least three or more colors of colored light or white light. It suffices to have a light source unit). The light source unit may be the same as the light source unit 3 of the above-mentioned optical line sensor unit, but the white LED light source 3W in the light source unit 3 is omitted, or each monochromatic LED light source 3R, 3G, 3B, The configuration may be such that 3V is omitted. Further, the light source unit is not limited to a configuration that emits four colored lights of red, green, blue, and purple, and may be capable of emitting at least three colors of colored light. Further, the light source unit is not limited to the LED, and may be configured by other light sources such as LD or a combination thereof, and the combination of each color is also arbitrary. The optical line sensor unit (second optical line sensor unit A or second optical line sensor unit B) on the corrected side simultaneously emits three or more colors of light, or emits white light from the white LED light source 3W. Make it emit light. Then, the light is applied to the reference color chart, and the reflected light or transmitted light from the reference color chart is received by the light receiving unit 12 (second light receiving unit). As a result, the second reference light receiving output of each color is acquired.

Then, the first reference light receiving output acquired by the reference optical line sensor unit (first optical line sensor unit) and the corrected optical line sensor unit (second optical line sensor unit A or second optical line sensor unit) are used. Using the second reference light receiving output acquired in B), a coefficient matrix composed of a plurality of matrix elements as exemplified in the above equations (1) and (2) is calculated by the minimum square method. Based on the matrix element of this coefficient matrix, the inverse matrix of the coefficient matrix is calculated and stored in the storage unit of the optical line sensor unit (second optical line sensor unit A or second optical line sensor unit B). When an object such as a sheet of paper is read by the optical line sensor unit (second optical line sensor unit A or second optical line sensor unit B) on the corrected side, the reflected light or transmitted light from the object is read. Is received by the light receiving unit 12 (second light receiving unit), and the light receiving output of each color is acquired. Then, the light receiving output of each color is corrected by performing an operation as exemplified in the above equations (3) to (5) using the inverse matrix of the coefficient matrix for the light receiving output of each color.

<When the RGB single color LED light source is turned on at the same time: (2nd optical line sensor unit A>
Read the reference color chart when the RGB monochromatic LED light sources are turned on sequentially (independently) (first optical line sensor unit) and when the RGB monochromatic LED light sources are turned on at the same time (second optical line sensor unit A). The RGB light receiving sensor output is obtained, and then the RGB values obtained by A / D (8 bits) conversion are converted into (X, Y, Z) values by the 3 × 3 matrix of CIE1931 to (x, Y, Z). y) The chromaticity value is obtained, and the difference (Δx, Δy) is used as the color difference in the present invention for ^each color C1 to C24 of the reference color chart, and the ^square root of Δx2 + Δy2 is used as the color difference in the present invention. Shown in 19B. The length of the line segment in FIGS. 19A and 19B is the color difference.

FIG. 19A shows the color difference between the case where the RGB monochromatic LED light source is sequentially turned on (first optical line sensor unit) and the case where the monochromatic RGB LED light source before correction is turned on at the same time (second optical line sensor unit A). The corrected color difference is shown when the RGB single-color LED light sources are sequentially turned on (first optical line sensor unit) and when the single-color RGB LED light sources are turned on at the same time (second optical line sensor unit A). According to FIGS. 19A and 19B, the color difference (the length of the line segment is long) between the second optical line sensor unit A and the first optical line sensor unit before the correction is small (the length of the line segment) after the correction. Is short). The square marks in FIGS. 19A and 19B indicate the chromaticity when the RGB monochromatic LED light sources are sequentially lit (first optical line sensor unit), and the circle marks indicate the chromaticity when the monochromatic RGB LED light sources are simultaneously lit (second optical line sensor). It represents the chromaticity when unit A) is performed.

<For fluorescent white LED: 2nd optical line sensor unit B>
Read the reference color chart when the RGB monochromatic LED light sources are turned on sequentially (independently) (first optical line sensor unit) and when the phosphor-type white LED light source is turned on (second optical line sensor unit B). The RGB value obtained by obtaining the RGB light receiving sensor output and then performing A / D conversion (8 bits) is converted into the (X, Y, Z) value by the 3 × 3 matrix of CIE1931 and (x, Y, Z). y) The chromaticity value is obtained, and the difference (Δx, Δy) is shown in FIGS. 20A and 20B for each of the colors C1 to C24 of the reference color chart.

FIG. 20A shows the color difference when the phosphor-type white LED light source before correction is turned on (second optical line sensor unit B) and the RGB single-color LED light source is turned on sequentially (first optical line sensor unit). FIG. 20B. The color difference between when the RGB single-color LED light source is turned on sequentially and when the phosphor-type white LED light source is turned on and corrected is shown. The square marks in FIGS. 20A and 20B indicate the chromaticity when the RGB monochromatic LED light sources are sequentially turned on (first optical line sensor unit), and the circle marks turn on the phosphor-type white LED light source before correction (the first optical line sensor unit). It represents the chromaticity when the second optical line sensor unit B) is used. According to FIGS. 20A and 20B, the color difference (the length of the line segment) when the fluorescent white LED light source is turned on and when the single color RGB LED light source is turned on sequentially is small (the length of the line segment is long) after the correction. It can be seen that the length is short).

<Color reproducibility of paper leaves>
Regarding the color reproduction range of paper sheets, when the RGB monochromatic LED light source, which is the reference light source, is turned on sequentially (independently) (first optical line sensor unit) and when the RGB monochromatic LED light source is turned on at the same time (second optical line sensor). 21 to 23 show the color reproduction range when the unit A) is turned on and when the phosphor type white LED light source is turned on (second optical line sensor unit B). Further, the color reproduction is corrected for the color reproduction range when the RGB single color LED light source is turned on at the same time (second optical line sensor unit A) and when the phosphor type white LED light source is turned on (second optical line sensor unit B). The regions are also shown in FIGS. 21 to 23.

According to FIGS. 21A, 21B, 22A, 22B, 23A, and 23B, the RGB monochromatic LED light source is simultaneously lit (second optical line sensor unit A), and the color gamut after correction is larger than that before correction. It is wide and can reproduce the area beyond the color gamut of sRGB, and it is close to the color reproduction range when the single color RGB LED light source is turned on sequentially (independently) (first optical line sensor unit). I understand.
Further, according to FIGS. 21C, 21D, 22C, 22D, 23C, and 23D, the color reproduction range of the white LED light source (second optical line sensor unit B) after correction is wider than that before correction. Moreover, it can be seen that the region beyond the color gamut of sRGB can be reproduced, and that the color reproduction region is approaching when the monochromatic RGB LED light sources are sequentially (independently) lit (first optical line sensor unit).

In the present invention, the time for the output of the white LED light source 3W to rise from 10% to 90% and the time for the output to fall from 90% to 10% are 2 μsec or less, respectively, so that the response is responsive. Paper leaves can be read at high speed using a high white LED light source 3W.

In particular, since the white LED light source 3W uses a highly responsive YAG phosphor as the phosphor, paper sheets can be read at a higher speed.

Further, when the RGB monochromatic LED light sources are turned on at the same time, high-speed reading becomes possible at a speed equal to or higher than that of the white LED light source.

<Action effect>
As described above, for example, each RGB obtained by using a reference color chart based on the case where RGB monochromatic light sources having a wide color reproduction range are sequentially (independently) turned on (first optical line sensor unit). The reference color chart is used when the "gain value of the light receiving sensor" and "when the RGB monochromatic light source is turned on at the same time (second optical line sensor unit A) or when the white LED light source is turned on (second optical line sensor unit B)". By obtaining the relationship with the "gain value of each RGB sensor obtained" from (Equation 1) to (Equation 3), the RGB monochromatic LED light sources having a wide color reproduction range are sequentially (independently) lit (first). It is possible to obtain a color reproduction range that is extremely close to that of the optical line sensor unit).

Up to this point, in order to realize a wide color reproduction range, make the color reproduction of intermediate colors accurate, and make the authenticity judgment accurate, mainly the case where the RGB monochromatic LED light sources are turned on sequentially (independently) is the reference light source. However, as described above, the RGB monochromatic light source is not limited to LEDs, but uses an optical filter to create RGB light with sharp transmission spectrum characteristics (first optical line sensor unit), and the reference color. An RGB light receiving sensor obtained through an RGB optical filter when the RGB monochromatic LED light source is simultaneously turned on (second optical line sensor unit A) or when the white LED light source is turned on (second optical line sensor unit B) using a chart. The RGB light receiving sensor gain value when the inverse matrix element of (Equation 3) is obtained by using (Equation 1) to (Equation 3) and the optical filter is used (first optical line sensor unit). May be converted to. Furthermore, using an RGBLD (Laser Diode) light source instead of the RGB monochromatic LED light source as the reference light source, and using (Equation 1) to (Equation 2), the inverse matrix element of (Equation 3) is obtained, and RGB of RGBLD is obtained. It may be converted into the gain value of the sensor. In addition, a light source having three or more colors having various colored lights may be used as the reference light source. However, the number of colored lights of the reference optical line sensor unit and the number of colored lights of the optical line sensor unit on the corrected side are the same.

The line light source 10 is not limited to the configuration in which light is incident on the light guide body 1 from one or both end faces of the longitudinal direction L and the light is diffused / refracted by the light diffusion pattern P. The configuration may be such that light is directly applied to the focal plane 20 from the bottom side surface 1a side via the light emitting side surface 1d (so-called direct type). In this case, a plurality of ultraviolet light sources may be provided side by side along the longitudinal direction of the light guide body, and the ultraviolet light may be incident on the inside of the light guide body. Further, the infrared light source may face one end face in the longitudinal direction of the light guide body, and infrared light may be incident on the inside of the light guide body from the one end face. Further, a white LED light source and a plurality of monochromatic LED light sources (at least two of monochromatic LED light sources 3R, 3G, and 3B of each RGB color) face the other end face in the longitudinal direction of the light guide and are guided from the other end face. Light may be incident inside the light body.

In the above embodiment, the configuration to which the present invention is applied to the side light double-sided incident type optical line sensor unit has been described. However, the present invention is not limited to the side light double-sided incident type, for example, a side light one-sided incident type, a direct type, a mixed method of a direct type and a side light type (one-sided incident), or a direct type and a side light type (both-sided incident type). ) Can be applied to various other optical line sensor units such as the mixed system.

1 Light guide 3 Light source 3W White LED light source 3R, 3G, 3B, 3V Monochromatic LED light source 4 Light source 10 Line light source 11 Lens array 12 Light receiving part P Light diffusion pattern

Claims (18)

It is a light receiving output correction method that corrects the light receiving output of the second optical line sensor unit based on the light receiving output acquired by using the first optical line sensor unit.
The first optical line sensor unit is
A first light source unit capable of emitting at least three colors of colored light, and
It is provided with a first light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light from the first light source unit.
The color light is emitted independently so that the three or more color lights are not mixed, or the spectrum of an arbitrary color light is emitted in a narrow band spectrum so as not to be mixed with the spectrum of another color light, and a predetermined standard is used. By receiving the reflected light or the transmitted light from the color chart at the first light receiving unit, the first reference light receiving output of each color is acquired.
The second optical line sensor unit is
The second light source unit capable of emitting at least three colors or white light, and the second light source unit.
A second light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light or white light from the second light source unit is provided.
By simultaneously emitting the three or more colors of light, or by emitting the white light and receiving the reflected light or the transmitted light from the reference color chart by the second light receiving unit, the second reference light receiving of each color is received. It gets the output,
When the first reference light receiving output is represented by a linear function using a coefficient matrix by the second reference light receiving output, the matrix element of the coefficient matrix is calculated by the least squares method, and at the same time.
The second optical line sensor unit simultaneously emits three or more colors of light, or the white light is emitted and the reflected light or transmitted light from the object is received by the second light receiving unit to receive each color. The optical line sensor unit is characterized by acquiring the light receiving output of the above and correcting the light receiving output of each color by using the inverse matrix of the coefficient matrix calculated based on the matrix element of the coefficient matrix. Light receiving output correction method. It is a light receiving output correction system that corrects the light receiving output of the second optical line sensor unit based on the light receiving output acquired by using the first optical line sensor unit.
The first optical line sensor unit is
A first light source unit capable of emitting at least three colors of colored light, and
It is provided with a first light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light from the first light source unit.
The color light is emitted independently so that the three or more color lights are not mixed, or the spectrum of an arbitrary color light is emitted in a narrow band spectrum so as not to be mixed with the spectrum of another color light, and a predetermined standard is used. By receiving the reflected light or the transmitted light from the color chart at the first light receiving unit, the first reference light receiving output of each color is acquired.
The second optical line sensor unit is
The second light source unit capable of emitting at least three colors or white light, and the second light source unit.
A second light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light or white light from the second light source unit is provided.
By simultaneously emitting the three or more colors of light, or by emitting the white light and receiving the reflected light or the transmitted light from the reference color chart by the second light receiving unit, the second reference light receiving of each color is received. It gets the output,
When the first reference light receiving output is represented by a linear function using a coefficient matrix by the second reference light receiving output, the matrix element of the coefficient matrix is calculated by the least squares method, and at the same time.
The second optical line sensor unit simultaneously emits three or more colors of light, or the white light is emitted and the reflected light or transmitted light from the object is received by the second light receiving unit to receive each color. The optical line sensor unit is characterized by acquiring the light receiving output of the above and correcting the light receiving output of each color by using the inverse matrix of the coefficient matrix calculated based on the matrix element of the coefficient matrix. Light receiving output correction system. The color light is emitted independently so that at least three or more color lights are not mixed, or the spectrum of any color light is emitted in a narrow band spectrum so as not to be mixed with the spectrum of another color light, and the color light is irradiated. An optical line sensor that corrects the light-receiving output based on the first reference light-receiving output of each color acquired by receiving the reflected light or transmitted light from a predetermined reference color chart.
The second light source unit capable of emitting at least three colors or white light, and the second light source unit.
A second light receiving unit that receives reflected light or transmitted light from an object irradiated with colored light or white light from the second light source unit.
The second of each color obtained by simultaneously emitting the three or more color lights or emitting the white light and receiving the reflected light or the transmitted light from the reference color chart by the second light receiving unit. A storage that stores the inverse matrix of the matrix elements of the coefficient matrix when the first reference light output is represented by a linear function using a coefficient matrix by the second reference light output calculated based on the reference light output. With a part,
The light receiving output of each color is obtained by simultaneously emitting the three or more colored lights, or by emitting the white light and receiving the reflected light or the transmitted light from the object by the second light receiving unit. An optical line sensor unit characterized in that the light receiving output of each color of the above is corrected by using the inverse matrix of the coefficient matrix. When the first reference light receiving output is represented by a piecewise linear function by the second reference light receiving output, the inverse matrix of the matrix elements of the coefficient matrix is stored in the storage unit for each section. The optical line sensor unit according to claim 3. The optical line sensor unit according to claim 3 or 4, wherein the three or more colors of colored light are colored light emitted by an LED. The optical line sensor unit according to claim 3 or 4, wherein the three or more colors of colored light are colored light emitted by the LD. The optical line sensor unit according to claim 3 or 4, wherein the three or more colors of the colored light are a mixture of the colored light emitted by the LED and the colored light emitted by the LD. The optical line sensor unit according to claim 3 or 4, wherein the white light is emitted by a blue or purple LED and a phosphor. When the three or more colors of light are emitted at the same time, the RGB 3-color LED is turned on at the same time, the RGV 3-color LED is turned on at the same time, or the RGB 3-color LED or a light source obtained by mixing the RGV 3-color LED and the white LED is used at the same time. Whether to turn on the RGB 3-color LD at the same time, turn on the RGV 3-color LD at the same time, turn on the RGB 3-color LD or the light source that is a mixture of the RGV 3-color LD and the white LED at the same time, or turn on the LED and LD at the same time. The optical line sensor unit according to claim 3 or 4, wherein a light source mixed with white LEDs is turned on at the same time. 3. The optical line sensor unit described. The optical line sensor unit according to claim 8, wherein the phosphor is a YAG phosphor. A light guide body having a long shape and having an exit surface formed along the longitudinal direction,
A light diffusion pattern provided along the longitudinal direction of the light guide body to diffuse light incident on the inside of the light guide body and emit it from the emission surface.
Further provided with a light source that faces one end face in the longitudinal direction of the light guide and allows arbitrary colored light to enter the inside of the light guide from the one end face.
The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region.
The second light source unit faces the one end surface in the longitudinal direction of the light guide body, and is characterized in that a color light different from that of the light source is incident on the inside of the light guide body from the one end surface. Item 6. The optical line sensor unit according to any one of Items 3 to 11. A light guide body having a long shape and having an exit surface formed along the longitudinal direction,
A light diffusion pattern provided along the longitudinal direction of the light guide body to diffuse light incident on the inside of the light guide body and emit it from the emission surface.
Further provided with a light source that faces one end face in the longitudinal direction of the light guide and allows arbitrary colored light to enter the inside of the light guide from the one end face.
The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region.
The second light source unit faces the other end face in the longitudinal direction of the light guide, and is characterized in that a color light different from that of the light source is incident on the inside of the light guide from the other end face. The optical line sensor unit according to any one of 3 to 11. A light guide body having a long shape and having an exit surface formed along the longitudinal direction,
It is further provided with a light source which is provided side by side along the longitudinal direction of the light guide and allows arbitrary colored light to be incident inside the light guide.
The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region.
The optical line sensor unit according to any one of claims 3 to 11, wherein the second light source unit is provided in a different arrangement from the light source along the longitudinal direction of the light guide body. A light guide body having a long shape and having an exit surface formed along the longitudinal direction,
Further provided with a light source that faces one end face in the longitudinal direction of the light guide and allows arbitrary colored light to enter the inside of the light guide from the one end face.
The light source is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region.
The optical line sensor unit according to any one of claims 3 to 11, wherein the second light source unit is provided in a different arrangement from the light source along the longitudinal direction of the light guide body. A light guide body having a long shape and having an exit surface formed along the longitudinal direction,
A light source that faces one end face in the longitudinal direction of the light guide and injects arbitrary colored light into the inside of the light guide from the one end face.
Further provided with another light source that faces the other end face in the longitudinal direction of the light guide and injects colored light different from the light source into the inside of the light guide from the other end face.
Each of the light sources is a light source having a spectrum of color light of at least one division when the spectrum of the arbitrary color light is divided into an ultraviolet region, a visible region, and an infrared region.
The optical line sensor unit according to any one of claims 3 to 11, wherein the second light source unit is provided in a different arrangement from the light source along the longitudinal direction of the light guide body. Of the plurality of monochromatic light sources that emit at least three colors of light, the peak wavelength of the emission spectrum of the monochromatic light source that emits blue monochromatic light is shorter than the peak wavelength of the emission spectrum in the blue wavelength region of the white light. The optical line sensor unit according to any one of claims 3 to 16, characterized in that it has a wavelength. Further provided with a lens array for guiding light emitted from the second light source unit and reflected or transmitted by the object.
The optical line sensor unit according to any one of claims 3 to 17, wherein the second light receiving unit receives light converged by the lens array and converts it into an electric signal.

Images