JPH0553218A - 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:Reflected light from an image visual field range 2a on the surface of the original 2 corresponding to one picture element line of an image recognizing element 10 is converged by an image forming lens 8 and made incident on the saw-tooth shaped opening part 62 of the grating 61. The light made incident on the opening part 62 is diffracted at a different angle corresponding to the wavelength and the R, G, and B light beams are made incident on picture element lines 23, 22, and 21 of a CCD 10 respectively. In this case, noise light 63 which is reflected by the surface of the original 2 outside the image visual field range does not pass through the opening part 62 of the grating 61, but travels straight outside, so the noise light is made incident on none of the respective picture element lines 21, 22, and 23. Namely, the reflected light is resolved by the opening part 62 of the grating 61 into three colors and made incident on the CCD 10, so the need for a buffer memory is eliminated.

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 copying device.

[0002]

2. Description of the Related Art The construction of an optical system of a digital color image copying apparatus 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. 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.

The spectral sensitivity characteristic of the color filter 25 is shown in FIG.
It shows in (a). This figure shows the relative sensitivities of G and R when the maximum value of B output is 1. FIG. 7B shows the relative sensitivity of the original image corresponding to the relative sensitivity of the color filter 25 as a curve 31. Outputs SB, SG, SR of the CCD 10 for each color of B, G, R when the original image is color-separated by the color filter 25 are shown in FIG. 7C.
In each case, the integrated value is within the range indicated by the diagonal lines. By using these outputs SB, SG, and SR, an electrostatic latent image is formed on the slam by a known means, and the image is reproduced by developing with three color toners, 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. 8 and 9. 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, suppose that the document surface is subdivided into a visual field range corresponding to the pixels 24 and the visual field range 11 is divided into pixel visual field ranges No. 6 to No. 14.
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, the buffer memory 4 as shown in FIG. 9 is used.
1 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 enables high-speed processing of color recognition of an input image, does not require a memory and a filter, and sets a pixel visual field range with high accuracy. It is an object of the present invention to provide a low-cost image input device that can be manufactured.

[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. The image input device is characterized in that a color separation prism having an opening corresponding to the visual field range on the document surface and having a sawtooth-shaped cross section is provided on the input surface of the image recognition element.

[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.

Further, by making the opening of the color separation prism correspond to the visual field range on the document surface, a mask for limiting the visual field range becomes unnecessary, and the number of parts can be reduced.

[0016]

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 and 2 show the configuration of an embodiment of the present invention. In these figures, parts corresponding to those of the conventional example shown in FIGS. 3 and 5 are designated by the same reference numerals, and the description thereof will be omitted as appropriate. The structure of the CCD 10 is the same as that of the conventional example, and the characteristic of the present embodiment is a color separation prism having a sawtooth-shaped cross section, which does not require the color filter 25 and the buffer memory 41 which are required in the conventional example.
The point is that the grating 61 is provided on the input section of the CCD 10.

The saw-tooth-shaped opening 62 formed in the grating 61 allows only the reflected light from the pixel visual field range 2a corresponding to one pixel line of the CCD 10 on the surface of the original 2. ..

Next, the operation of this embodiment will be described with reference to FIGS. Reflected light from the pixel visual field range 2a corresponding to one pixel line of the CCD 10 on the surface of the original 2 is condensed by the imaging lens 8 and is incident on the sawtooth-shaped opening 62 of the grating 61. The light that has entered the opening 62 is diffracted at different angles depending on the wavelength, and the R, G, and B lights enter the pixel lines 23, 22, and 21 of the CCD 10, respectively. At this time, since the grating 61 is formed by a method similar to the LSI manufacturing process, the manufacturing accuracy is high and the visual field range by the opening 62 can be set with high accuracy.
Further, the noise light 63 reflected from the surface of the original 2 other than the pixel visual field range 2a does not pass through the opening 62 of the grating 61 and travels straight outside, so that each pixel line 21, 22, 23.
Is never incident on.

According to the present embodiment, the reflected light from one pixel visual field range 2a on the document surface is simultaneously separated into three colors by the opening 62 of the grating 61 and enters the CCD 10, so that the buffer memory is It is not necessary, and the cost of the device can be reduced and the speed of color recognition can be increased. Further, since the color filter is not required and only the grating 61 is mounted on the CCD 10, the cost can be reduced and the product yield can be improved. Moreover, since the opening portion 62 for setting the visual field range is provided in the grating 61, it is not necessary to separately provide a light shielding member, and the number of parts and the number of assembling steps can be reduced.

[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.

Further, the visual field range can be set with high accuracy by the opening of the grating, and the number of parts and the number of assembling steps can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a grating according to an embodiment of an image input device of the present invention.

FIG. 2 is an explanatory diagram showing an image recognition operation according to the present embodiment.

FIG. 3 is an explanatory diagram showing a configuration of an example of an optical system of a digital color image copying apparatus.

FIG. 4 is a plan view of FIG.

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

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

FIG. 7 is a diagram illustrating an image color reproducing operation in a color image copying apparatus.

FIG. 8 is an explanatory diagram showing a color separation action of an example of a conventional color image copying apparatus.

FIG. 9 is an explanatory diagram showing a configuration of an example of a space map of a buffer memory provided in a conventional color image copying apparatus.

FIG. 10 is an explanatory diagram showing an example of a conventional method for producing a color filter.

[Explanation of symbols]

 2 Original 2a Pixel field of view 10 CCD (image recognition element) 61 Grating (color separation filter) 62 Aperture

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 input device for an image copying apparatus, comprising a color separation prism having an opening corresponding to a visual field range on the original surface and having a sawtooth cross section.