JPS60153257A - Color original reader - Google Patents

Abstract

PURPOSE:To fix the output signal levels of respective colors by controlling light made incident on respective photoelectric conversion elements through respective color filters in accordance with spectral sensitivity characteristics to respective colors of the photoelectric conversion elements. CONSTITUTION:The photoelectric conversion elements are formed by arranging (n) pieces of metallic electrodes 3 on an n type silicon substrate 1 with prescribed intervals like one array through a silicon oxide film 2. Red, green and blue transmitting filters R, G, B are successively and repeatedly arrayed on the upper layer in accordance with the positions of the metallic electrodes 3 and a filter element F laminated in each color is formed. Dousers 5 are provided over said filter F so as aperture widths ratio of aperture part 4 to be prescribed value. The area of the photodetecting surface of the photoelectric conversion element part is changed so that the photodetecting quantity received by each photoelectric conversion element is reversely proportional to a spectral sensitivity ratio to each color.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a document reading device, and more particularly to an improvement in a photoelectric conversion unit of a color document reading device such as a color facsimile or a color copier.

[Prior art]

In recent years, as a second-document reading method, color filters are sequentially arranged on the upper layer of a photoelectric conversion element section consisting of a CCD sensor etc. formed in a single row of arrays. A reading method that can read color originals is attracting attention.

A color document reading device using this reading method is
For example, as shown in FIG. 1 as a plan view and as shown in FIG. A CCD composed of metal electrodes 3 formed in an array.
The sensor is a photoelectric conversion section, and a red transmission filter R1, a green transmission filter G, and a blue transmission filter B are repeatedly arranged in order on the metal electrode at positions corresponding to each of the metal electrodes. It is set up.

However, in this method, the spectral sensitivity characteristics for each color of the photoelectric conversion section, which is the light receiving section, are as shown in Figure 5.
:Green (G):Blue (B)-1: 0.9: 0.6
Because the spectral sensitivity characteristics differ depending on the color,
Even if the amount of incident light that passes through the red transmission filter, green transmission filter, and blue transmission filter and enters the photoelectric conversion unit is the same, the resulting image signals for each color will be uneven, making it difficult to read the color image correctly. It was impossible.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a color document reading device that can accurately read a color document in one scan.

[Structure of the invention]

In order to achieve the above object, the present invention provides a color filter in which a color filter of a predetermined color is disposed on the upper layer of a photoelectric conversion section consisting of a plurality of photoelectric conversion elements arranged in parallel in an array. The document reading device is configured so that the amount of light received by each photoelectric conversion element in the photoelectric conversion section is inversely proportional to the spectral sensitivity ratio for each color, and the output signal level for each color is made constant.

Embodiment] Hereinafter, a color document reading device according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 3 is a plan view thereof, and FIG.
1 on a mold silicon substrate 1 through a silicon oxide film 2.
13μm x 13μm with predetermined spacing in an array of rows
A photoelectric conversion element part having the same width as the original is formed by forming n metal electrodes 3, and a red transmission filter R1 green transmission filter ○1 blue is placed on the upper layer corresponding to the position of the metal electrodes 3. A filter element F in which the transmission filters B are arranged repeatedly in sequence and stacked for each color, and a light shielding element formed on the filter element so that the aperture width ratio of the aperture 4 of each color transmission filter becomes a predetermined value. It consists of a plate 5 and a normal drive circuit section (not shown).

Further, the light shielding plate is composed of a metal thin film formed by vapor deposition on the color filter, and the metal electrode under each color filter has a size of 13 μm x 8 μm.
138mX10μm (m2), 134mX13μm (m
3), an opening is formed to control the amount of incident light. In other words, the amount of light that enters the metal electrode through the red transmission filter, the amount of light that enters the metal electrode through the green transmission filter, and the amount of light that enters the metal electrode through the blue transmission filter are: It is defined by the area ratio of the opening, and these area ratios are 8
μm×13μm=10μm×13μm: 13μm×13
μm=m1:m2:m3=0.6:0.9:1 The measurement results of the output signal level of each color of this color original reading device are almost constant as shown in FIG.

Furthermore, the presence of the light shielding plate also has the following effects.

In other words, due to the smear effect, in which light with a long wavelength (red light in this case) has a high penetration rate, red light is particularly likely to spread to adjacent elements (in this case, the green light reading unit). , the presence of the light shielding plate ζ prevents light from going around to adjacent elements.

Therefore, in this respect as well, the presence of the light shielding plate helps in correct reading of color images.

Next, other embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 7, this color original reading device has an n-type silicon substrate 1,
A red transmitting filter R1, a green transmitting filter G, and a blue transmitting filter are sequentially placed on a photoelectric conversion section formed by forming metal electrodes 3 at predetermined intervals in an array through a silicon oxide film 2. Filters B are arranged repeatedly and stacked one color for each element, with a metal electrode located under the red transmission filter, a metal electrode located under the green transmission filter, and a metal electrode located under the blue transmission filter, respectively. The area of each metal electrode is 13 μm x 13 μm (m
H'), 13μm×14μm (m2'), 1
3 μm x 22 μm (m3') ''nl H': m2': m3'=1
: 1.1 : 1.7.

With this configuration, it is possible to obtain a color document reading device with a good S/N ratio and a constant output signal level for each color.

That is, in the above embodiment in which a light shielding plate is provided and the signal level is adjusted to the blue signal level having the lowest sensitivity, the S/N
However, in the color original reading device of this example, by changing the area of the metal electrode that is the light receiving surface of the photoelectric conversion section, it is possible to avoid a decrease in the S/N ratio. It becomes possible to keep the output signal level constant.

In the examples, a CCD sensor was used for the photoelectric conversion element part, but in addition, a sandwich lateral photoelectric conversion method in which a photoconductor layer of amorphous silicon or the like is sandwiched between a metal electrode and a northern light electrode may be used. It goes without saying that other photoelectric conversion elements such as a photoelectric conversion element may also be used.

In addition, as a means for configuring the amount of light received by each color of each photoelectric conversion element to be inversely proportional to the spectral sensitivity ratio of the photoelectric conversion element, the density (
A method of stacking light amount adjustment filters with adjusted light shielding lids is also effective. In this method, for example, red, green,
Filters with lower densities are used in order of blue.

[Movement of the Invention] As explained above, according to the present invention, a color filter is disposed for each element in the upper layer of the charging conversion elements arranged in an array in rows. In a color original reading device that is made up of That is.

That is, in the color original reading device of the present invention, the light shielding plate is provided so that the amount of light received by the photoelectric conversion element through each color filter is inversely proportional to the spectral sensitivity ratio of each color of the photoelectric conversion element used. By adjusting the amount of light received and configuring the light receiving area of the photoelectric conversion element to be inversely proportional to the spectral sensitivity ratio of each color, it is possible to accurately read color documents in one scan. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic plan view of a conventional color document reading device, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG. 3 is a partial schematic plan view of a color document reading device according to an embodiment of the present invention. ,
FIG. 4 is a sectional view of A'=A' in FIG. 3, FIG. 5 is a comparison diagram of output signal levels of each color by a conventional color document reading device, and FIG. 6 is a color document of an embodiment of the present invention. FIG. 7, which is a comparison diagram of output signal levels of each color by the reading device, is a partial plan schematic diagram of a color document reading device according to another embodiment of the present invention. 1 n-type silicon substrate, 2 silicon oxide film, 3 metal electrode, 4 opening, 5 light shielding plate, F filter element, L photoelectric conversion section, R red transmission filter, G
...green transmission filter, B blue transmission filter. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 400 500 600 700 (nm) Figure 6

Claims (3)

[Claims] (1) - A color filter of a predetermined color is sequentially disposed for each photoelectric conversion element on the upper layer of a photoelectric conversion unit consisting of a plurality of photoelectric conversion elements arranged in parallel in an array. Power 2 - A color document reading device characterized in that the amount of light incident on the photoelectric conversion element is inversely proportional to the spectral sensitivity ratio of each color of the photoelectric conversion device. (2) The color filter further includes a light shielding body in the upper layer, and the light shielding body has an opening configured to be inversely proportional to the spectral sensitivity ratio for each color of each photoelectric conversion element. A force 2-original reading device according to claim (1). (3) Each of the photoelectric conversion elements is configured such that the area of the light receiving portion is inversely proportional to the spectral sensitivity ratio for each color of the photoelectric conversion element.
) The color document reading device described in section 2.