JP4091712B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus using an electroluminescence element.
[0002]
[Prior art]
Conventionally, a color image reading apparatus has three light sources that emit light in a wavelength range of red (hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as B). Then, the color image information of the document is read by irradiating the document while sequentially switching the three light sources.
[0003]
FIG. 13 is a diagram showing a configuration of a conventional color image reading apparatus. A conventional image reading apparatus will be described with reference to FIG.
[0004]
First, the original 1301 to be read is illuminated by the light sources 1302R, 1302G, and 1302B. The light source 1302R emits red, the light source 1302G emits green, and the light source 1302B emits blue. Here, the light sources 1302R, 1302G, and 1302B are fluorescent lamps.
[0005]
In order to perform color reading, first, the light sources 1302R, 1302G, and 1302B are sequentially turned on, and the original is illuminated with illumination light 1303R, 1303G, and 1303B. This illumination light is reflected by the original 1301, becomes reflected light 1304, and enters the image sensor 1306 through the lens 1305. The image sensor 1306 photoelectrically converts this light into an electric signal corresponding to the light intensity. This electrical signal is digitized by an A / D converter (not shown) and read as color image data separated into each color.
[0006]
In this way, the conventional image reading apparatus reads the color image data of the document 1301 by sequentially reading the color image information separated into the colors corresponding to the colors emitted from the light sources 1302R, 1302G, and 1302B.
[0007]
The light sources 1302R, 1302G, and 1302B are turned on using inverters 1307R, 1307G, and 1307B.
[0008]
[Problems to be solved by the invention]
However, a conventional color image reading apparatus has to perform high-frequency lighting in order to illuminate a document with a fluorescent lamp used as a light source. For this reason, an inverter is necessary for the conventional image reading apparatus. Therefore, the cost has increased and a space for mounting the inverter has been required.
[0009]
In order to uniformly illuminate the original, it is necessary to make the length of the fluorescent lamp longer than the width of the original in consideration of the fact that no light is emitted from the end of the fluorescent lamp. As an example, in order to illuminate a document width of A4 size (210 mm to 216 mm), a length of about 270 mm is required.
[0010]
Furthermore, since the fluorescent lamp has poor phosphor responsiveness, color switching cannot be performed at high speed. For this reason, a color image reading apparatus using a fluorescent lamp as a light source has a problem in that color separation is deteriorated and colors of a plurality of light beams are mixed. Therefore, it is difficult to perform high-speed reading in a color image reading apparatus using a fluorescent lamp as a light source.
[0011]
Conventionally, a form using an LED instead of a fluorescent lamp as a light source has been considered. However, an image reading apparatus using an LED as a light source has a problem that the LED has a low luminance and it is basically a point light source, so that it is difficult to obtain sufficient brightness. For this reason, it is considered that LEDs are arranged on a line to serve as a light source, but there has been a problem that the cost is increased.
[0012]
In order to solve this problem, it is also considered to use a form using an LED using a gallium nitride material having high luminance characteristics. However, LEDs using gallium nitride-based materials have a problem that they are very expensive compared to conventional LEDs. For this reason, it is considered to illuminate the entire document by arranging one to two LEDs of gallium nitride material at the end of a light guide system called a light guide. However, there is a problem that the configuration is complicated, and there is also a problem that a large amount of light cannot be obtained because there are few LEDs to be used.
[0013]
Further, as described in JP-A-6-284257, a form using an electroluminescence element (hereinafter referred to as an EL element) as a light source has been proposed. However, this publication only discloses monochrome image reading, and does not disclose any method applied to color image reading, and does not disclose a method using an EL element for color image reading.
[0014]
In addition, since the EL element has different light emission efficiency depending on the color of light emitted, it becomes a problem to compensate for the difference in light emission efficiency depending on the light emission color of the EL element.
[0015]
The present invention has been made in view of the above points, and is an image reading apparatus capable of realizing a color image reading apparatus that is reduced in size and improved in reading capability by using an EL element as a light source and simplifying the configuration. The purpose is to provide.
[0016]
[Means for Solving the Problems]
  The present inventionIt has electroluminescent elements that emit red, green, and blue primary colors for illuminating the document, and electroluminescent elements that emit blue with low luminous efficiency are arranged on both sides of the center line on the transparent substrate. A light source in which an electroluminescent element that emits another color is arranged on the side opposite to the center line of the arranged electroluminescent element that emits blue, and the translucent substrate is arranged in parallel and close to the read document; An image sensor that photoelectrically converts reflected light from the document and reads image information of the document by the photoelectrically converted electrical signal, and the light source controls the electroluminescence element to control the color of light. Irradiating light to the reading position of the document through the translucent substrate while sequentially switching the image sensor, A configuration read sequentially switching the reflected light incident transmitted through the centerline of the translucent substrate from the reading position of the document for each color of light emitted to the document.
[0017]
By using an electroluminescence element as a light source in this way, the configuration of the image reading apparatus is simplified and downsized. Further, the ability to read a color image is improved by effectively irradiating the original with light utilizing the characteristic that the electroluminescence element emits light.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  An image reading apparatus according to a first aspect of the present invention includes:It has electroluminescent elements that emit red, green, and blue primary colors for illuminating the document, and electroluminescent elements that emit blue with low luminous efficiency are arranged on both sides of the center line on the transparent substrate. A light source in which an electroluminescent element that emits another color is arranged on the side opposite to the center line of the arranged electroluminescent element that emits blue, and the translucent substrate is arranged in parallel and close to the read document; An image sensor that photoelectrically converts reflected light from the document and reads image information of the document by the photoelectrically converted electrical signal, and the light source controls the electroluminescence element to control the color of light. Irradiating light to the reading position of the document through the translucent substrate while sequentially switching the image sensor, A configuration read sequentially switching the reflected light incident transmitted through the centerline of the translucent substrate from the reading position of the document for each color of the light irradiated to the document.
[0019]
By using the electroluminescence element as the light source in this way, the configuration of the image reading apparatus that reads the color image information of the original is simplified and miniaturized.
[0020]
Further, with this configuration, the color image information separated for each color irradiated from the light source to the original can be read reliably, so that the color image data of the original can be read reliably.
[0022]
  Also,With this configuration, not only can the light source be effectively downsized, but the light source can be placed in close contact with the document. For this reason, the image reading capability can be improved.
[0024]
  Also,With this configuration, light of a color with low light emission efficiency can be strongly applied to the document, so that a difference in luminance applied to the document according to the color can be eliminated. For this reason, the color image reading ability of the document is improved.
[0027]
  First of the present invention2The aspect of the firstAspectIn the image reading device,The width of the end portion of the electroluminescence element is wider than the width of the central portion..
[0029]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0030]
The present invention employs an electroluminescence element (hereinafter referred to as EL element) as a light source of a color image reading apparatus. As a configuration using an EL element as a light source of a color image reading apparatus, (1) a system in which red, green, and blue elements are arranged like a CRT such as a TV, (2) a system in which white light emission and a color filter are combined, (3) A method of combining blue light emission and a color conversion layer can be considered.
[0031]
The method (1) does not use a color conversion layer like the method (2) or the method (3), and the use efficiency of light emission is good. Therefore, in the present invention, the method (1) will be mainly described.
[0032]
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a color image reading apparatus according to Embodiment 1 of the present invention. The color image reading apparatus according to the first embodiment will be described in detail with reference to FIG.
[0033]
The original 101 to be read is irradiated with light from the light source 102.
[0034]
The light source 102 includes an EL element 104R that emits light of red wavelength, an EL element 104G that emits light of green wavelength, and an EL element 104B that emits light of blue wavelength on the opposite side of the original 101 of the glass substrate 103. The structure is taken.
[0035]
Further, the light source 102 is disposed in the vicinity of the document 101 and obliquely with respect to the document 101. For this reason, the light source 102 irradiates the original 101 with light from an oblique direction.
[0036]
Since the EL element 104B has lower luminous efficiency than the other EL elements 104R and 104G, the EL element 104B is arranged closest to the position where the document is irradiated with light. This is because the reflected light becomes stronger when light is incident at an angle close to perpendicular to the original 101.
[0037]
The EL elements 104 </ b> R, 104 </ b> G, and 104 </ b> B are attached with their surfaces inclined toward the reading point of the document 101 so that light efficiently strikes the reading point of the document 101.
[0038]
The lens 105 is a lens for forming an image of reflected light from the original on the image sensor 106.
[0039]
The image sensor 106 photoelectrically converts light information from the formed image into an electrical signal corresponding to the intensity of the light and outputs the electrical signal.
[0040]
Further, since the three primary colors are applied to the color of light emitted from the light source 102, color separation is made clear, so that it is possible to effectively read a color image that has been color-separated.
[0041]
The document 101 is sandwiched between rollers 107a and 107b, and is fed in the direction of the arrow 108 as the rollers 107a and 107b rotate.
[0042]
Hereinafter, the light source 102 which is a feature of the present invention will be described in detail with reference to the drawings.
[0043]
FIG. 2 is a configuration diagram of the EL element according to the first embodiment. Here, before describing the light source 102 in detail, the EL element will be described with reference to FIG.
[0044]
An EL element using electroluminescence is self-luminous and a completely solid element. For this reason, since it has characteristics such as excellent impact resistance, it is attracting attention as a light emitting element in various display devices.
[0045]
This EL element includes an inorganic EL element using an inorganic compound as a light emitting material and an organic EL element using an organic compound. Of these, the organic EL element can significantly reduce the applied voltage and consumes less power. In addition, the organic EL element can be easily downsized, can emit surface light, and can easily emit three primary colors. For this reason, organic EL elements have been actively researched and developed as next-generation light-emitting elements. In the present invention, an organic EL element is used as a light source.
[0046]
The EL element 104 is formed by sequentially laminating a transparent electrode 201 made of ITO (indium oxide mixed with tin), a light emitting layer 202, and a back electrode 203 made of Mg (magnesium) / Ag (silver) on a glass substrate 103. Has been created.
[0047]
The glass substrate 103 is made of glass having a transparency that transmits the emitted light. In consideration of productivity and cost, the thickness of the glass substrate 103 is about 1 mm.
[0048]
The light emitting layer 202 includes an electron transport layer 204 in which negative charges (electrons) easily flow, and a hole transport layer 205 in which positive charges (holes that are holes for electron transport) easily flow.
[0049]
The hole transport layer 205 is in contact with the transparent electrode 201, and the electron transport layer 204 is stacked in contact with the back electrode 203. The total thickness of the electron transport layer 204 and the hole transport layer 205 is 1 / 1,000 mm or less.
[0050]
Next, the light emission operation of the EL element 104 will be described with reference to FIG.
[0051]
When a DC voltage is applied with the back electrode 203 side minus and the transparent electrode 201 side plus, electrons having a negative charge flow into the electron transport layer 204 from the back electrode 203, and holes from the transparent electrode 201 side become holes. It flows into the transport layer 205. Electrons and holes reach the interface between the electron transport layer 204 and the hole transport layer 205, and at this interface, negative electrons and positive holes attract each other, and the electrons are joined so as to fill the holes that are shells. To do. This bond is called recombination of electrons with holes. At this time, electron energy is emitted in the form of light.
[0052]
As described above, the EL element 104 emits light by applying electricity to the organic thin film and flowing positive and negative DC currents. Further, since the applied DC voltage is 10 to 15 V, the voltage can be easily used in a general color image reading apparatus.
[0053]
Further, the light source of the color image reading device is required to have a high response speed in order to switch R / G / B light to emit light. However, the EL element 104 has a very high response speed of the light emitting element, that is, the time from applying a voltage to emitting light, the time from turning off the voltage to turning off, 1 millionth of a second. . For this reason, the EL element 104 is very suitable as a light source for a color image reading apparatus.
[0054]
FIG. 3 is an enlarged cross-sectional view for explaining the configuration of the light source according to the first embodiment. The light source concerning Embodiment 1 is demonstrated in detail using this figure.
[0055]
The light source 102 has a structure in which EL elements 104R, 104G, and 104B are attached to a glass substrate 103.
[0056]
The EL element 104R is an EL element that emits light in the red wavelength range, the EL element 104G is an EL element that emits light in the green wavelength range, and the EL element 104B is an EL element that emits light in the blue wavelength range. .
[0057]
With such a configuration, the light source 102 emits red, green, and blue light through the glass substrate 103 by the light emitted from the EL elements 104R, 104G, and 104B.
[0058]
Further, by applying the three primary colors to the color of light emitted from the light source 102 in this way, the color discrimination of the light becomes clear, so that color-separated color images can be read effectively.
[0059]
FIG. 4 is a top view of the light source according to the first embodiment. Using this figure, how the EL elements 104R, 104G, and 104B are provided in the light source 102 will be described.
[0060]
On the glass substrate 103 of the light source 102, EL elements 104R, 104G, and 104B are arranged in the width direction of the document. When the original to be read is an A4 original (210 mm to 216 mm), the optimum length 401 of the EL elements 104R, 104G, 104B arranged on the glass substrate 103 is about 230 mm. This length 401 is a length that can illuminate the document evenly without adversely affecting the size of the apparatus. This length 401 is longer than the width of the document because it is necessary to consider not only light directly irradiated from above but also reflected light in order to illuminate the document uniformly. This is because it is necessary to irradiate light. The size of light sources for other size documents such as A3 documents can be determined in the same way.
[0061]
The width 402R of the EL element 104R, the width 402G of the EL element 104G, and the width 402B of the EL element 104B are the same.
[0062]
However, the light emission efficiency of the EL elements 104R, 104G, and 104B and the wavelength characteristics and resolution of the lenses and the image sensor are different. Therefore, various modification examples can be considered when the widths of the EL elements 104R, 104G, and 104B are optimized in consideration of changing the widths of the EL elements 104R, 104G, and 104B to compensate for these characteristic differences.
[0063]
FIG. 5 is a top view of a modification of the light source according to the first embodiment. In this modification, the blue light emitter is considered to have lower luminous efficiency than the other color light emitters. The sensitivity of the image sensor is lower than other colors for blue light.
[0064]
In the light source 102a of the modified example, EL elements 104R, 104G, and 104B are arranged with a length 401. This length 401 is the same as the length 401 in FIG.
[0065]
A width 501B of the EL element 104B arranged in the light source 102a is wider than a width 501R of the EL element 104R and a width 501G of the EL element 104G. For this reason, the surface area of the EL element 104B is larger than the surface areas of the other EL elements 104R and 104G. As described above, by increasing the surface area of the EL element 104B, it can be compensated that the luminous efficiency is lower than that of the light emitters of other colors.
[0066]
FIG. 6 is a top view of a modification used in the reduction optical system of the light source according to the first embodiment. In this modification, due to the characteristic of the cosine fourth power rule of the lens, the characteristic that the peripheral portion of the lens becomes darker than the center of the lens is considered.
[0067]
In the light source 102b of this modification, EL elements 104R, EL elements 104G, and EL elements 104B are arranged with a length 401. This length 401 is the same as the length 401 in FIG.
[0068]
The width 601R at the end of the EL element 104R arranged in the light source 102b, the width 601G at the end of the EL element 104G, and the width 601B at the end of the EL element 104B are the width 602R at the center of the EL element 104R and the width 602R of the EL element 104G. The center width 602G is wider than the center width 602B of the EL element 104B.
[0069]
With such a configuration, the light emission efficiency of the end portions of the EL elements 104R, 104G, and 104B is increased, so that the original can be irradiated evenly through the lens.
[0070]
As described above, various modifications of the light source are conceivable. In the following description of the first embodiment, the light source shown in FIG. 4 is adopted.
[0071]
Hereinafter, a color image reading operation of the image reading process according to the first embodiment will be described.
[0072]
FIG. 7 is a timing chart for explaining the control of the lighting time of each EL element of the light source according to the first embodiment. The operation of the light source 102 and the reading operation according to the first embodiment will be described with reference to FIGS. 1 and 7.
[0073]
First, at t0, a voltage is applied to the EL element 104R to light it, and the red light beam 109R is illuminated on the document.
[0074]
The light beam 109 </ b> R passes through the glass substrate 103 and reaches the original 101, and is reflected by the original 101 to become reflected light 110. The reflected light 110 enters the lens 105, becomes a light beam 111 formed by the lens 105, and forms an image on the image sensor 106.
[0075]
The light beam 111 is photoelectrically converted into an electric signal corresponding to the intensity of light by the image sensor 106 and output as an electric signal 112. The electric signal 112 is digitized by an A / D converter (not shown) to become image data. In this way, image information of a portion corresponding to the red color of the document 101 is obtained.
[0076]
At t1, the voltage applied to the EL element 104R is set to 0 to stop light emission, and the EL element 104G is turned on by applying voltage to illuminate the original with the green light beam 109G. Since the subsequent processing is the same as that when the light beam 109R is irradiated from the EL element 104R to the original 101, description thereof is omitted.
[0077]
Thus, image information corresponding to the green color of the document 101 is obtained by irradiating the document with the light beam 109G from the EL element 104G.
[0078]
At t2, the voltage applied to the EL element 104G is set to 0 to stop light emission, and the EL element 104B is turned on by applying voltage to illuminate the original with the blue light beam 109B. The subsequent processing is the same as the case where the original 101 is irradiated with the light beams 109R and 109G from the EL elements 104R and 104G, and a description thereof will be omitted.
[0079]
In this manner, the image information corresponding to the blue color of the document 101 is obtained by irradiating the document with the light beam 109B from the EL element 104B.
[0080]
At t3, the voltage applied to the EL element 104B is set to 0 and light emission is stopped. The time between t0 and t1, between t1 and t2, and between t2 and t3 is all the same Δt.
[0081]
However, the light source 102 is disposed closest to the position at which the EL element 104B irradiates the original with light compared to the other EL elements 104R and 104G. In this way, the low light emission efficiency of the EL element 104B is compensated.
[0082]
Although the light emission times of all the EL elements 104R, 104G, and 104B are the same, the EL element 104B is disposed closest to the irradiation position of the document 101, so that the light emission efficiency of the EL element 104B is the other EL element 104R, It is compensated that it is lower than 104G.
[0083]
Thus, when image information corresponding to each color of the original 101 is obtained, the original 101 is then sent in the direction of the arrow 108 by the rollers 107a and 107b, and the image information at the position of the next original is read.
[0084]
By repeating this process, the color image information of the entire document 101 can be read.
[0085]
It is also conceivable to optimize the lighting time control of the EL elements 104R, 104G, 104B in consideration of the light emission efficiency of the EL elements 104R, 104G, 104B.
[0086]
FIG. 8 is a timing diagram for explaining a modification of the lighting time control of each EL element of the light source according to the first embodiment.
[0087]
In this modification, the EL element 104B is irradiated between t2 and t4. The time during this period is 2Δt. In this manner, by increasing the irradiation time of the EL element 104B having poor light emission efficiency, it is possible to compensate for the light emission efficiency of the EL element 104B being worse than that of the other EL elements 104R and 104G.
[0088]
In FIG. 8, the irradiation time of the EL element 104B is set to 2Δt. However, the irradiation time can be set to other than 2Δt in consideration of the light emission efficiency of the EL element 104B.
[0089]
As described above, since the first embodiment uses an EL element as a light source, the light source is significantly reduced in size. In addition, an inverter or other device that is necessary for a light source using a conventional fluorescent lamp becomes unnecessary. Therefore, the mounting volume and cost of the entire color image reading apparatus are greatly reduced.
[0090]
Further, since the EL elements 104R, 104G, and 140B emit surface light, a light guide that is necessary when an LED is used as a light source is not necessary.
[0091]
Further, according to the first embodiment, since the light emission efficiency by the light emission color of the EL element can be supplemented, the reading ability can be prevented from being lowered.
[0092]
Further, in the first embodiment, the light source of FIG. 4 is mainly used as the light source and the control of the light source is described using the method of FIG. 7, but the light source of FIG. 5 or 6 is used as the light source, and the method of FIG. By applying or combining these, it is possible to effectively supplement the light emission efficiency of the light emission color of the EL element.
[0093]
(Embodiment 2)
FIG. 9 is a diagram showing a configuration of a color image reading apparatus according to the second embodiment of the present invention. The color image reading apparatus according to the second embodiment will be described in detail with reference to FIG. In addition, the same code | symbol is provided about what has already been demonstrated.
[0094]
The second embodiment has the same configuration as that of the first embodiment except for the light source 901.
[0095]
In the light source 901, the glass substrate 103 is disposed in parallel and close to the original 101. Actually, the distance between the light source 901 and the document 101 is about 1 mm.
[0096]
For this reason, the luminous efficiency is greatly improved as compared with the first embodiment. Further, since the distance between the light source 901 and the original 101 is short, the color image reading apparatus is downsized.
[0097]
FIG. 10 is a top view of the light source according to the second embodiment. The configuration of the light source according to the second embodiment will be described in detail with reference to FIG. The same reference numerals are given to the same components as already described.
[0098]
The light source 901 is provided with two EL elements 104B across the center line 901. Further, the light source 901 has the EL element 104B disposed at a position close to the reading point of the document. For this reason, it is supplemented that the luminous efficiency of the EL element 104B is lower than that of the other EL elements 104R and 104G.
[0099]
Next, the operation of the image recording apparatus according to the second embodiment will be described with reference to FIG.
[0100]
Since control of the EL elements 104R, 104G, and 104B is the same as that in Embodiment 1, the description thereof is omitted.
[0101]
Light emitted from the light source 901 is applied to the reading position of the document 101 through the glass substrate 103. This light is reflected from the document 101 and reaches the lens 105 via the center position of the glass substrate 103 of the light source 901, that is, the center line 901 in FIG.
[0102]
Since the subsequent operation is the same as that of the first embodiment, the description thereof is omitted.
[0103]
As described above, in the second embodiment, the light reflected from the original reaches the lens through the glass substrate of the light source, so that the light source can be brought close to the original. For this reason, it is possible to reduce the size of the color image reading apparatus and to improve the irradiation efficiency of the light source on the document.
[0104]
In addition, by providing a plurality of EL elements that emit blue light and close to the reading position of the original, it is possible to compensate for the low luminous efficiency of the EL elements that emit blue light.
[0105]
Furthermore, by changing the width of the EL element arranged in the light source as shown in FIGS. 5 and 6 or changing the irradiation time as shown in FIG. 7, an EL element that emits more blue light. Can compensate for the low luminous efficiency.
[0106]
By adopting the timing shown in FIG. 8 for controlling the lighting time of each EL element, it is possible to effectively compensate for the low luminous efficiency of the EL element that emits blue light.
[0107]
(Embodiment 3)
In Embodiment 3, a light source using an EL element is applied to the contact image sensor.
[0108]
FIG. 11 is a diagram illustrating a configuration of the contact image sensor according to the third embodiment. In addition, the same code | symbol is provided to the same thing as already demonstrated.
[0109]
The contact image sensor 1101 is different from the image reading apparatus of the reduction optical system as described in the first embodiment or the second embodiment in that it is a horizontally long image sensor having the same width as the document 101. 1102 is different from the portion having the lens array 1103 of the equal-magnification imaging optical system for imaging the reflected light from the original 101 on the image sensor 1102. Other configurations and operations are the same as those in the first embodiment, and are omitted.
[0110]
Such a contact-type image sensor 1101 is miniaturized because it does not require a long optical path length unlike a reduction optical system sensor. Further, since the pixel size of the image sensor 1102 matches the reading size, high sensitivity can be obtained. Furthermore, since the light source 102, the lens 1103, and the image sensor 1102 can be integrated, there is an advantage not only in downsizing but also in apparatus adjustment.
[0111]
Thus, the light source 102 using an EL element is very small and is lit with a constant DC voltage, and thus is suitable as a light source for the contact image sensor 1101. Further, the shape of the EL element can be the same as or wider than that of the original 101 as shown in FIG.
[0112]
Here, a modification using the light source employed in the second embodiment for the contact image sensor will be described.
[0113]
FIG. 12 is a diagram illustrating a configuration of a modified example of the contact image sensor according to the third embodiment. In addition, the same code | symbol is provided to the same thing as already demonstrated.
[0114]
In this example, the light source 901 is used as reading glass. Therefore, the configuration is simpler than that of the image sensor 1101. Further, since the positions of the original 101 and the light source 901 are very close, the light emission efficiency is also improved.
[0115]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an image reading apparatus capable of realizing a color image reading apparatus that is reduced in size and improved in reading ability by simplifying the configuration using an EL element as a light source. .
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a color image reading apparatus according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of an EL element according to the first embodiment.
FIG. 3 is an enlarged sectional view for explaining the configuration of the light source according to the first embodiment;
FIG. 4 is a top view of the light source according to the first embodiment.
FIG. 5 is a top view of a modification of the light source according to the first embodiment.
FIG. 6 is a top view of a modification used in the reduction optical system of the light source according to the first embodiment.
FIG. 7 is a timing chart for explaining control of lighting time of each EL element of the light source according to the first embodiment;
FIG. 8 is a timing chart for explaining a modification of the lighting time control of each EL element of the light source according to the first embodiment;
FIG. 9 is a diagram showing a configuration of a color image reading apparatus according to a second embodiment of the present invention.
FIG. 10 is a top view of a light source according to the second embodiment.
FIG. 11 is a diagram showing a configuration of a contact image sensor according to a third embodiment of the present invention.
FIG. 12 is a diagram showing a configuration of a modified example of the contact image sensor according to the third embodiment.
FIG. 13 is a diagram showing a configuration of a conventional color image reading apparatus.
[Explanation of symbols]
101 manuscript
102,901 Light source
103 Glass substrate
104R, 104G, 104B Electroluminescence element (EL element)
105, 1103 lenses
106, 1102 Image sensor
1101, 1201 Contact image sensor

Claims (2)

It has electroluminescence elements that emit red, green, and blue primary colors for illuminating the original, and the electroluminescence elements that emit blue light with low luminous efficiency are arranged on both sides of the center line on the translucent substrate. A light source in which an electroluminescent element that emits another color is arranged on the opposite side of the center line of the arranged electroluminescent element that emits blue, and the translucent substrate is arranged in parallel and close to a reading document; An image sensor that photoelectrically converts reflected light from the document and reads image information of the document by the photoelectrically converted electrical signal, and the light source controls the electroluminescence element to control the color of light. the light irradiated sequentially switched while reading position of the document through the transparent substrate, while the image sensor Image reading apparatus characterized by reading sequentially switching the reflected light incident transmitted through the centerline of the translucent substrate from the reading position of the document for each color of the light irradiated to the document. The image reading apparatus according to claim 1, wherein the width of the end portion of the electroluminescent element was wider than the width of the central portion.

Images