JPH0229065A - Color picture reader - Google Patents

Abstract

PURPOSE:To read a color picture accurately at a fast speed by providing a region where each light emission characteristic of plural light sources has an overlapped wavelength and using red and yellow group light emitting diodes with high light emission efficiency as light sources. CONSTITUTION:A fluorescent light 12 and a light emission diode unit 13 are mounted in a case 11, a red orange color, a yellow light and a blue light from plural linear red orange, yellow light emission diodes 13R, 13Y of a linear configuration from a fluorescent light 12 radiates 4 a line l on an original 1 detected by an image light detection section 3a of a CCD line sensor 3. The radiated wavelength regions of the light emitting diodes 13R, 13Y and the fluorescent light 12 are continuous and the light of the continuous wavelength region from nearly 400nm to nearly 700nm radiates. The red orange light of one line by plural red orange light emitting diodes 13R, the yellow light of one line by plural yellow light emitting diodes 13Y and the blue color light of one line by the fluorescent light 12 radiates for each step when the original 1 is sent in time division.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image reading device suitable for use in color image transmission devices, color image copying devices, and the like.

[Summary of the invention]

The present invention is a color image reading device suitable for use in a color image transmission device, a color image copying device, etc., which uses light from a red light emitting diode, a yellow light emitting diode, and a blue fluorescent light source. is irradiated onto the original, and the reflected light from the original is received to obtain a color image. By selecting the light emitting characteristics of the light sources so that their wavelengths overlap, the colors on the document can be read quickly and accurately with a simple configuration using light emitting diodes.

[Conventional technology]

Conventionally, as a color image reading device used in a color image transmission device, a color image copying device, etc., a device as shown in FIG. 6 has been proposed (Japanese Patent Laid-Open No. 58-212255). In this color image reading device, a reading section (2) is arranged close to a document (1) on which a color image is drawn by printing or the like. The angle filter section (2) is connected to the image light detection section (3).
a) is the CCD line sensor (3) facing the original (1)
is the installation. This image light detection section (3a) is connected to the original (1).
The length corresponds to the width. A multi-lens array (4) in which a plurality of rod-shaped lenses are arranged linearly is arranged between the image light detection section (3a) of this CCD line sensor (3) and the original (1). The image light of one line in the width direction of the original (1) is made to enter the image light detection section (3a) of the CCD line sensor (3) via the one-full lens array (4).

A fluorescent lamp (4) that emits blue light with a length corresponding to the width of the document (1) is installed close to the side surface of the multi-lens array (4).
5) is placed, and the original (
1), and a lamp with a length corresponding to the width of the original (1) is placed close to the side of the multi-lens array (4) opposite to this fluorescent lamp (5). A light emitting diode unit (6) is arranged. This light emitting diode unit (6) has a substrate (6a) as shown in FIG.
), red light emitting diodes (6R) and green light emitting diodes (6G) are arranged alternately in a straight line, and by making the red light emitting diodes (6R) emit light, the original (1) is irradiated with red light. By causing the green light emitting diode (6G) to emit light, the document (1) is irradiated with green light.

The document (1) close to this reading section (2) is configured to be sent by a roller (7), and the document (1) is transported by a roller (7).
1) is read by this roller (7).
Irradiation of red light by R), green light emitting diode (6G)
The irradiation of green light by the fluorescent lamp (5) and the irradiation of blue light by the fluorescent lamp (5) are repeated in a time-sharing manner. Then, the image light from the document (1) during irradiation of each color is detected and read by the image light detection section (3a) of the CCD line sensor (3). In this way, by separating the image light of the color image drawn on the original (1) into the three primary colors of red, green, and blue and reading them line by line, the primary color signals of the color image can be read line by line. By sending the document (1) for one screen, the primary color signals of the color image for one screen are read.

By using a light emitting diode as a light source in this way, the configuration of the reading device is simplified and the power consumption during reading is reduced.

[Problem to be solved by the invention]

However, since the light emitting wavelength region of the light emitting diode is very sharp, the above-described configuration has the disadvantage that intermediate colors other than red, green, and blue cannot be accurately read.

That is, the light emitting characteristics of the respective light emitting diodes (6R) and (6G) and the fluorescent lamp (5) are as shown in FIG. i length λP - about 6
60 nm, the green light emitting diode (6G) has a peak wavelength λp = approximately 555 nm, the blue fluorescent lamp (5) has a peak wavelength λp = approximately 450 nm, and the light emitting diodes (6R) and (6G) have a half width of approximately 30 nm. Because it was so narrow, the respective emission wavelength regions did not overlap at all. For this reason, for example, it has not been possible to distinguish subtle differences in yellow color tone with a wavelength of about 600 nm, which is between red and green, using the output signal of this reading device.

Further, since green light emitting diodes have low luminous efficiency, green light must be irradiated for a longer time than other colors, resulting in the inconvenience that reading takes time.

In view of these points, it is an object of the present invention to provide a color image reading device that has a simple configuration using light emitting diodes and can read color images quickly and accurately.

[Means to solve the problem]

As shown in FIGS. 1 to 3, for example, the color image reading device of the present invention switches and controls a plurality of color light sources, and uses a light receiving means (3) to receive reflected light from a document (1) irradiated by the light source. In a color image reading device that receives light to obtain a color image, the light source is a red light emitting diode (
13R), a yellow light emitting diode (13Y), and a blue fluorescent light source (12).
3Y) is selected to have a region where the wavelengths of the luminescent characteristic values overlap, and the blue fluorescent light source (12) is selected so that the luminescent characteristic value is the value of the luminescent characteristic of the light emitting diode (13Y) whose luminescent characteristic value is yellowish. It is selected so that it has a region where the wavelength overlaps with the wavelength.

(Function) According to the color image reading device of the present invention, a plurality of light sources (one
2) Since each of the emission characteristics of (13Y) and (13R) has a region where the wavelengths overlap, the light receiving means ( 3) can be received, and the colors on the document (1) can be read accurately.

Furthermore, since red and yellow light emitting diodes with high luminous efficiency are used as light sources, images can be read at high speed.

〔Example〕

Hereinafter, one embodiment of the color image reading device of the present invention will be described.
This will be explained with reference to FIGS. In FIGS. 1 to 5, parts corresponding to those in FIG. 6 are designated by the same reference numerals.
A detailed explanation thereof will be omitted.

In FIG. 1, (10) indicates an image reading section, and this image reading section (10) has an open bottom surface of a housing (11), and an original document that can be moved by a roller (7) on the bottom surface of the case (11).
1) is set. The direction of movement of this document (1) (direction of arrow A) is the longitudinal direction of the document (1), and the width of the document (1) (orthogonal to the longitudinal direction) is provided on the top surface of this casing (11). A CCD line sensor (
3) is attached, and a multi-lens array (4) is arranged between this image light detection section (3a) and the set original (1). A fluorescent lamp (12) emitting fruit-colored light, which will be described later, is attached close to one side of the multi-lens array (4). The length of this fluorescent lamp (12) is approximately the same as the width of the original (1). A light emitting diode unit (13) is attached adjacent to the other side of the multi-lens array (4).

As shown in FIG. 2, this light-emitting diode unit (13) has a plurality of red-orange light-emitting diodes (13R) that emit red-orange light (described later) on a strip-shaped substrate (13a) in the width direction of the original (1). A plurality of red-orange light emitting diodes (13R
), a plurality of yellow light emitting diodes (13Y) that emit yellow light (described later) are arranged in a straight line in the width direction of the document (1) at predetermined intervals, and are arranged in two rows. There is. Note that the length W of this substrate (13a) is the original (
The width is approximately the same as 1).

This fluorescent lamp (12) and light emitting diode unit (13)
Since the image light detection section (3a) of the CCD line sensor (3) detects the document (
1) The upper line 2 is irradiated with red-orange light and yellow light from a plurality of linear red-orange and yellow light emitting diodes (13R) and (13Y), and is irradiated with fruit-colored light from a fluorescent lamp (12). Ru.

In this example, each light emitting diode (13R)
.

The light from (13Y) and the fluorescent lamp (12) are made to have characteristics as shown in FIG. That is, a red-orange light emitting diode (13
R) uses a yellow light emitting diode (13Y) that emits red t-chromatic light with a peak wavelength λP = 630 nm.
uses one that emits yellow light with a peak wavelength λP = 568 nm. Furthermore, the fluorescent lamp (12) has a peak wavelength of λp=approximately 450 nm, similar to a normal blue fluorescent lamp, but emits fruit and vegetable colors that extend to a region close to green, with the upper limit of the emission wavelength range extending to approximately 550 r+m. use something By setting in this way, each light emitting diode (13
1? ), (13Y) and the fluorescent lamp (12) have continuous emission wavelength ranges, from about 400 nm to about 700 nm.
Light in a continuous wavelength range up to nm is irradiated.

When the image reading section (10) reads a color image on the original (1), the original (1) is set so as to face the reading section (10) as shown in FIG. This document (1) is sent in predetermined steps by a roller (7). Then, for each step in which this document (1) is sent, a plurality of red-orange light emitting diodes (13R) irradiate red-orange light on the L line, and a plurality of yellow light-emitting diodes (13R) emit red-orange light on the line.
Irradiation of yellow light of l line by Y) and fluorescent lamp (12)
Irradiation of one line of fruit and vegetable color light is performed in a time-division manner. That is, when the irradiation state of each color is shown in FIG. 4A-C, the irradiation of red-orange light (at the high level in FIG.
The timing control circuit (+8
) (see Figure 5), this is repeated in a time-sharing manner. Note that the blue color light irradiation by the fluorescent lamp (12) is performed for a somewhat longer time than other colors because the fluorescent lamp (12) has some afterglow time due to its characteristics. In this way, red-orange light, yellow light, and blue color light are irradiated on the same line at each step when the document (1) is fed, and each time the original (1) is irradiated, the CCD line sensor (3) detects an image formed by this irradiation. Detect light. As shown in the fourth diagram, this detection is carried out by the CCD line sensor (3) at a predetermined time after the completion of irradiation of each color, and is converted into an electrical signal.

Therefore, red-orange image light, yellow image light, and blue-based color image light are detected for each line, and a color image divided into three colors can be read, and the original (1) is fed by one screen by the roller (7). By doing so, it is possible to read one screen worth of color image drawn on the original (1).

Next, FIG. 5 shows a circuit configuration for processing the output signal of this CCD line sensor (3). As shown in FIG. 5, the output signal as image information from the CCD line sensor (3) is converted into a digital signal by an analog/digital converter (14). The digital signal output from this converter (14) is directly supplied to the color processing circuit (15), and
The signal is supplied to the color processing circuit (15) via the first delay circuit (16), and further to the color processing circuit (15) via the second delay circuit (17). In this case, the first and second delay circuits (16) and (17) are the timing control circuit (
18) controls the delay time. This timing control circuit (18) is connected to the fluorescent lamp [12] and the light emitting diode (13Y) via the fluorescent lamp driving circuit (19), the yellow light emitting diode driving circuit (20), and the red-orange light emitting diode driving circuit (21). ), (13R) is a circuit that controls the light emission of the above-mentioned lights as shown in FIG. 4. Under the control of this timing control circuit (18), the first delay circuit (16) receives the input signal for the time 1+ (see Figure 4) from the time when the blue light is irradiated until the time when the reddish-orange light is irradiated. The second delay circuit (17) is controlled by the timing control circuit (18) to determine the time tz from when the yellow light is irradiated to when the red-orange light is irradiated. The input signal is delayed by (see FIG. 4) and supplied to the color processing circuit (15).

By supplying the signals to the color processing circuit (15) in this way, the output signal of the CCI line sensor (3) during blue color irradiation and the output signal of the CCD line sensor (3) during yellow irradiation are generated. and CCD line sensor during red-orange irradiation (3)
The output signal is supplied to the color processing circuit (15). That is, each image is taken into the CCD line sensor (3) at the timing shown in the fourth diagram, and the blue line receives the same output (Fig. 4 G), while the yellow line receives the first output. The delay circuit (16) allows the time t, l
The output delayed by L2 (FIG. 4F) is output to the red-orange light line by a second delay circuit (17) for a time L2.
An extended output (FIG. 4E) is obtained.

The color processing circuit (15) includes a circuit that converts a red-orange signal, a yellow signal, and a blue-based color signal into a red signal, a green signal, and a blue signal under preset conditions based on the mixing ratio of the red-orange signal, yellow signal, and blue color signal. There is. This mixing ratio is determined by the coefficient means , , , , , 3, and the coefficients , , , , , , , and 3 are determined according to the predetermined characteristics of the yellow signal. After each color signal is multiplied by a coefficient, it is combined by an adding means (22) to create a green color signal. In this way, the red signal is based on the ratio of the signals of each color that are simultaneously supplied to the color processing circuit (15).

Create three primary color signals, a green signal and a blue signal, and send each signal to the red signal output terminal (15R) and the green signal output terminal (15R).
5G) and blue signal output terminal (15B),
Obtain a color image signal as a primary color signal. In addition, in order to obtain an appropriate color image signal, the data is valid only when appropriate signals appear on the red-orange signal line, yellow signal line, and blue color signal line, so the switch means (
23) is controlled by a timing control circuit (18). That is, the switch means (23) is turned on at the timing shown in FIG. 4H to obtain a color image signal for one line.

The color image reading device of this example has a simple configuration using light emitting diodes (13R) and (13Y) as light sources for two of the three colors, and the wavelength of the irradiated light can be adjusted as described above. The area becomes continuous without missing parts, and the color of the image on the document (1) can be accurately read within this continuous area. Since the signal converted into a normal three primary color signal using the circuit configuration shown in FIG. 5 is output as a read signal, a normal color signal processing circuit can be used in the subsequent circuit. Further, since yellow light emitting diodes have higher luminous efficiency than green light emitting diodes, images can be read more efficiently and at higher speed than conventional reading devices using green light emitting diodes.

Note that the peak wavelengths of the irradiated light from the light emitting diodes (13R) and (13Y) are not limited to the dual embodiment, and light emitting diodes and C odes having values in the vicinity thereof may be used. However, it is preferable to set the difference between the peak wavelength value of the red frame light emitting diode and the peak wavelength value of the yellow light emitting diode to be about 50 to 70 nm to improve the overlap of the wavelength ranges of the irradiated light. Further, in the embodiments described above, a fluorescent lamp was used as a blueish light source, but a fluorescent panel that emits the same light may also be used.

Furthermore, the present invention does not confine to the above-described embodiments, and without departing from the gist of the present invention, 1. Of course, various other configurations are possible.

〔Effect of the invention〕

The color image reading device of the present invention uses light emitting diodes (13R) and (13Y) as light sources for two of the three colors.
), the light emitting characteristics of each light source have regions where the wavelengths overlap, so reflected light from the original (+) of all wavelengths from red to blue can be reflected from the original (+). There is an advantage that the light receiving means (3) can receive the light, and the colors on the original (1) can be accurately read. Further, since the two-color light emitting diodes (13R) and (13Y) use red and yellow colors with high luminous efficiency, there is an advantage that images can be read at high speed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a color image reading device of the present invention, FIG. 2 is a perspective view showing main parts of the embodiment, FIG. 3 is a characteristic diagram for explaining the embodiment, and FIG. 4 is a waveform diagram for explaining one embodiment, FIG. 5 is a configuration diagram showing a read signal processing circuit of one embodiment, FIG. 6 is a sectional view showing an example of a conventional reading device, and FIG. A perspective view showing the main parts of the example in Figure 6, No. 8
This figure is a characteristic diagram for explaining the example in FIG. 6. (1) is a document, (10) is an image reading section, (12) is a fluorescent lamp, (13R) is a red-orange light emitting diode, and (13Y) is a yellow light emitting diode. Figure 1 of the @ side of 1j of 10 reading J's evil reading cross section

Claims (1)

[Scope of Claims] A color image reading device that controls switching of a plurality of color light sources, and obtains a color image by receiving reflected light from a document irradiated by the light source using a light receiving means, The red light emitting diode and the yellow light emitting diode have light emitting characteristics in a region where their wavelengths overlap. and the blue fluorescent light source is selected to have a region in which the value of the light emitting characteristic overlaps in wavelength with the value of the light emitting characteristic of the yellow light emitting diode. Device.