JPH0553219A - Image input device - Google Patents

Abstract

PURPOSE:To speed up color recognition processing and to reduce the cost by using a grating which is a saw-tooth shaped prism as a means for resolving the colors of an original image. CONSTITUTION:The grating 62 being the color resolving prism sectioned in a saw-tooth shape is provided on the input surface of an image recognizing element 10. In this case, the reflected light from an original 2 is made incident on the grating 61 through the opening part of a light shield member. The light which is made incident on the grating 61 is diffracted at a different angle corresponding to the wavelength and the R, G, and B light beams are made incident on picture elements 10R, 10G, and 10B of a CCD 10. At this time, the respective picture elements 10R, 10G, and 10B are different in opening shape, so light outputs corresponding to a specific spectral sensitivity curve are obtained from the respective picture elements. Consequently, the spectral sensitivity characteristics of the incident light shown by coordinates P-X are obtained by the CCD 10 to accurately reproduce the colors of the image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device provided in a digital color image transfer device.

[0002]

2. Description of the Related Art The construction of an optical system of a digital color image transfer device is shown in FIGS. In the figure, a document 2 placed on a document table 1 is irradiated with light emitted from a light source 4 provided on a first carriage 3. This light manuscript 2
The reflected light from the first mirror 5 is reflected at a right angle by the first mirror 5 fixed to the first carriage 3, and the second mirror 6 and the third mirror 6 fixed to a second carriage (not shown).
It is reflected by the mirror 7 and becomes light parallel to the document table 1. This light is an image recognition element by the imaging lens 8 and the fourth mirror 9 which are fixed to the apparatus main body.
It is condensed on the CCD 10.

The light emitted from the light source 4 illuminates a predetermined visual field range 11 on the surface of the original 2 as shown in FIG. Then, by moving the carriage 3 in the direction of arrow A, the entire surface of the original 2 is scanned. At this time, the moving speed of the carriage 3 is the mirror 6,
7 is twice the moving speed of the fixed carriage, and the optical path length from the light source 4 to the CCD 10 is the carriage 3
It is always constant regardless of the position. Therefore, the image on the original 2 can always be focused on the CCD 10.

Next, the structure of the conventional CCD 10 will be described with reference to FIGS. 6 and 7. The CCD 10 is provided with pixel lines 21, 22, and 23 for receiving blue (B), green (G), and red (R) light, respectively. Pixel line 21,
22 and 23 each have a large number of pixels 24 arranged in a line, and the size of the pixel 24 is, for example, 10 μm × 1.
0 μm, pixel line length 50 mm, spacing 200 μm
Is. Further, B, G, and R color filters 25 are provided on the surfaces of the pixel lines 21, 22, and 23, respectively.

FIG. 8 shows the spectral sensitivity characteristic of the color filter 25.
It shows in (a). This figure shows the relative sensitivities of G and R when the maximum value of B output is 1. FIG. 8B shows a curve 31 indicating the relative sensitivity of the original image corresponding to the relative sensitivity of the color filter 25. Outputs SB, SG, SR of the CCD 10 for each color of B, G, R when the original image is separated by the color filter 25 are shown in FIG.
In each case, the integrated value is within the range indicated by the diagonal lines. By using these outputs SB, SG, and SR to form an electrostatic latent image on the slum by a known means, and developing the image with three color toners to reproduce the image, the spectral characteristics of the three color toners are shown in FIG. ), The outputs SB, SG, SR of the CCD 10 are proportional to the outputs. In this way, the color image is reproduced.

Next, a conventional memory required for image reproduction will be described with reference to FIGS. 9 and 10. The light reflected from the document 2 is equivalently converted into linear light and imaged on the pixel lines 21, 22, and 23 of each color by the imaging lens 8. Therefore, the part of the document 2 which is incident on each of the pixel lines 21, 22, and 23 at the same time is another part. For example, if the document surface has pixels 24
The field of view 11 corresponds to No. 6
No. 14 to No. 14 pixel view range.
The pixel visual field ranges of 6, No. 10, and No. 14 are incident on the pixel lines 23, 22, and 21, respectively. This R, G, B
Table 1 below shows changes over time in the visual field range on the document surface corresponding to each pixel line 21, 22, 23.

[0007]

[Table 1]

Therefore, the CC of the same pixel visual field range on the original 2
In order to output the spectral outputs SB, SG, and SR of D10 at the same time, it is necessary to temporarily store these outputs. Therefore, conventionally, a buffer memory 41 as shown in FIG. 13 was provided. The number M of memories required in the configuration of the buffer memory 41 is as shown in the following formula (1). M = (tone of 1 pixel) × (vertical document visual field range / pixel visual field range) × (horizontal document visual field range / pixel visual field range) × 3 (1)

Next, a method of manufacturing the color filter 25 will be described with reference to FIG. First, in step 51, the CCD 10 in which three CCD pixel lines 102 are formed on the Si substrate 101 is prepared, and in step 52, the photosensitive resist 103 is applied to the surface of the CCD 10 on the side where the pixel lines 102 are formed. Then step 53
At the position of the blue pixel line 102B, the photomask 105 having the opening 104 only at the position corresponding to the blue pixel line 102B
The surface of D10 is covered, and the pixel line 102 is irradiated with light.
The portion of the photosensitive resist 103 corresponding to B is exposed and cured. Next, in step 54, the photosensitive resist 103 which is not cured is removed and development is performed, and only the cured resist 106 is left. Next, in step 55, the cured resist 106 is dyed to form a blue color filter 107, and in step 56, the surface of the CCD 10 is coated with a transparent dye-proof layer 108.

The above steps are followed by the green and red pixel lines 10
Repeatedly for 2G and 102R, the three color filters 107 formed in step 57,
The surfaces of 109 and 110 are covered with the overcoat layer 111, and the production of the color filter 25 on the CCD 10 is completed.

[0011]

According to the conventional image input device constructed as described above, the image of the original 2 is transferred to the CCD.
Since the buffer memory 41 is required to read the color and recognize the color at 10, there is a problem that the cost becomes high and high-speed processing cannot be performed. Also, pixel 2 of CCD 10
Color filter 25 corresponding to R, G and B directly on
Since it is manufactured by the photolithography method, there is a problem that the process is complicated, the yield is bad, and the cost is also high.

The present invention has been made in view of the above circumstances, and provides an image input apparatus capable of high-speed processing of color recognition of an input image and reducing costs by eliminating a memory and a filter. The purpose is to provide.

[0013]

SUMMARY OF THE INVENTION An image input apparatus of the present invention is an image copying apparatus in which a color original is scanned with light and the reflected light is separated into three colors and input to three image recognition elements. In the image input device, a color separation prism with a sawtooth cross section is provided on the input surface of the image recognition element, and the aperture shape of the image recognition element corresponding to each color is set to the wavelength band of the human spectral sensitivity curve. It is characterized by matching with.

[0014]

In the image input device having the above structure, the image in the same visual field range on the document surface is separated into three colors by the color separation prism through the opening formed in the light shielding member, and each color is corresponded. It is possible to input to the image recognition element at the same time. Therefore, the buffer memory and the color filter are not required, and it is possible to reduce the cost of the device and achieve high-speed color recognition. Moreover, since the aperture shape of the image recognition element corresponding to each color is matched with the wavelength band of the human spectral sensitivity curve, the light output corresponding to the human spectral sensitivity curve is obtained from the image recognition element of each color. Colors can be reproduced accurately.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image input device of the present invention will be described below with reference to the drawings.

1 to 3 show the configuration of an embodiment of this embodiment. The feature of this embodiment is that the color filter 25 and the buffer memory 41, which are required in the conventional example, are not required, and the grating 61, which is a color separation prism having a sawtooth-shaped cross section, is provided on the input surface of the CCD 10. The CCD 10 has an improved opening shape, and the other parts have the same configuration as the conventional example.

Pixels 10B, 10G, and 10R, which are B, G, and R image recognition elements provided on the CCD 10, respectively.
The opening shape of each is, for example, a parallelogram, an inverted triangle,
It has a triangular shape, and the respective light receiving sensitivity characteristics are shown by SX coordinates in FIG. This characteristic corresponds to the wavelength band of the human spectral sensitivity characteristic shown in FIG.

Next, the operation of this embodiment will be described with reference to FIGS. The reflected light from the original 2 is incident on the grating 61 through the opening of a light shielding member (not shown). The spectral characteristic of this incident light is shown by the P ₀ -λ coordinate in FIG. The light incident on the grating 61 is diffracted at different angles depending on the wavelength, and the R, G, and B lights are CC
The light enters the pixels 10R, 10G, and 10B of D10. At this time, since the aperture shapes of the pixels 10R, 10G, and 10B are different, the light output corresponding to the human spectral sensitivity curve shown in FIG. 3 is obtained from each pixel. As a result CCD
10, the spectral sensitivity characteristic of the incident light as shown by coordinates P-X in FIG. 1 can be obtained, and the color of the image can be accurately reproduced.

According to the present embodiment, the reflected light from one pixel visual field range on the original surface is color-separated into three colors at the same time by the grating 61 and is incident on the CCD 10, so that a buffer memory is not required and the cost of the apparatus is reduced. Reduction and high-speed processing of color recognition are possible. Further, since the color filter is not required and only the grating 62 is mounted on the CCD 10, it is possible to reduce the cost and improve the product yield. Further, since the aperture shapes of the pixels corresponding to B, G, and R of the CCD 10 are made to correspond to the wavelength bands of the human spectral sensitivity curve, the color of the image can be accurately reproduced.

The shape of the aperture of the pixel is not limited to that shown in this embodiment, and may be any other shape as long as it corresponds to the wavelength band of the human spectral sensitivity curve.

[0021]

As described above, according to the image input apparatus of the present invention, since the grating which is the sawtooth prism is used as the means for separating the color of the original image, the buffer memory and the color filter are not required, It is possible to realize speeding up of color recognition processing and cost reduction. Moreover, since the aperture shape of the pixel corresponding to each color corresponds to the wavelength band of the human spectral sensitivity curve, the color of the image can be accurately reproduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a main part of an optical system of an embodiment of an image input apparatus of the present invention.

FIG. 2 is a perspective view showing the CCD of FIG.

FIG. 3 is a diagram showing human spectral sensitivity characteristics.

FIG. 4 is an explanatory diagram showing a configuration of an example of an optical system of a digital color image transfer device.

5 is a plan view of FIG.

6 is a perspective view showing the configuration of the CCD shown in FIG.

7 is a sectional view taken along line XX of FIG.

FIG. 8 is a diagram illustrating an image color reproducing operation in a color image transfer device.

FIG. 9 is an explanatory diagram showing a color separation action of an example of a conventional color image transfer device.

FIG. 10 is an explanatory diagram showing an example of a configuration of a space map of a buffer memory provided in a conventional color image transfer device.

FIG. 11 is an explanatory diagram showing an example of a conventional method for producing a color filter.

[Explanation of symbols]

 2 Originals 10 CCD (image recognition element) 61 Grating (color separation prism)

Claims (1)

[Claims] 1. An image input device of an image copying apparatus, wherein a color original is scanned with light, and reflected light is color-separated into three colors and input to three image recognition elements, respectively. An image characterized in that a color separation prism having a sawtooth-shaped cross section is provided on the top, and the aperture shape of the image recognition element corresponding to each of the colors is matched with the wavelength band of the human spectral sensitivity curve. Image input device for copying machine.