JP2006278115A - Electrooptical device, image printer and image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a clear spot image by guiding light from a light-emitting element without expanding it in an optically-transparent substrate, in an electrooptical device. <P>SOLUTION: This electrooptical device includes: a main substrate 220; the light-emitting elements 205 formed on the main substrate 220; and a sealing substrate 230 for sealing the light-emitting elements 205 by being superposed on the main substrate 220. The sealing substrate 230 has optical waveguides 235 penetrating its front surface to its back surface; each optical waveguide 235 is formed of an optically-transparent material; its shape forms a cylindrical form; its circumferential surface is covered with a material (flat plate 231) having a refraction factor lower than that of the optically-transparent material; and a tip surface on the light-emitting element 205 side out of the tip surfaces thereof covers a light-emitting layer 210 constituting the light-emitting element 205. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electro-optical device that emits light from a light-emitting element through a light-transmitting substrate, and an image printing apparatus and an image reading apparatus that use the electro-optical device.

  As this type of electro-optical device, there are a bottom emission type and a top emission type. Light from the light emitting element is transmitted through the main substrate on which the light emitting element is formed in the bottom emission type, and is transmitted through the sealing substrate for sealing the light emitting element in the top emission type.

  FIG. 21 is a cross-sectional view showing an example of a conventional bottom emission type electro-optical device. In this figure, only the main part directly related to the problem to be solved of the present invention is hatched. This electro-optical device has an organic EL (ElectroLuminescent) element that emits light upon receiving electric energy as a light emitting element. This light-emitting element is formed over a light-transmitting main substrate 920 and includes a light-emitting layer 910. The light emitting layer 910 extends along the main substrate 920 and is made of an organic EL material.

  Light from the light emitting layer 910 has a certain extent, and most of the light enters the main substrate 920. Since the incident light further spreads within the main substrate 920, most of the light is emitted from the emission surface S900, but a part of the incident light is reflected by the emission surface S900. The light reflected here cannot be used. That is, from the viewpoint of the light use efficiency from the light emitting layer 910, the occurrence of reflection on the exit surface S900 is not desirable.

  Further, when this electro-optical device is used as an exposure head for forming an electrostatic latent image by irradiating light to an image carrier such as a photosensitive drum, all of the light emitted from S900 is used to form an electrostatic latent image. It is not always available. This is because it is common to form an electrostatic latent image using only light that has reached a plane area of a predetermined size. That is, when incident light spreads in the main substrate 920, even if all of the incident light is emitted from the emission surface S900, the light use efficiency from the light emitting layer 910 may be reduced.

In order to solve such problems, another electro-optical device has been proposed (Patent Document 1).
FIG. 22 is a cross-sectional view showing an example of another conventional electro-optical device. In this figure, only the main part directly related to the problem to be solved of the present invention is hatched. The electro-optical device illustrated in this figure is different from the above-described one in that the main substrate 930 is configured by embedding a bundle of optical fibers 935 (fiber array). Each optical fiber 935 penetrates the main substrate 930 in the thickness direction, and among the front end surfaces thereof, the inner one faces the light emitting layer 910 and the outer one constitutes an emission surface S905. In this electro-optical device, most of the light from the light emitting layer 910 is guided in the thickness direction of the main substrate 930 by the optical fibers 935 in the main substrate 930 and is emitted from the emission surface S905. As a result, a spot image having substantially the same size as that of the light emitting layer 910 is formed on the emission surface S905. In this electro-optical device, since the incident light does not spread on the main substrate 930, the above-described problem does not occur.
JP 2000-343752 A

However, the spot image formed on the exit surface S905 has another problem.
FIG. 23 is a view showing a spot image formed by the electro-optical device of FIG. As shown in this figure, on the emission surface S905, the luminance of the region (tip surface) corresponding to the vicinity of the center of the light emitting layer 910 is high, and the luminance of the region (tip surface) corresponding to the vicinity of the periphery of the light emitting layer 910 is low. . That is, the contour of the spot image is unclear. This can be a cause of lowering the print quality of the image printing apparatus when used as the exposure head described above.

The problems related to the conventional bottom emission type electro-optical device described above are common to the top emission type electro-optical device. These problems can also adversely affect an image reading apparatus using the electro-optical device as an optical head.
Based on the above-described circumstances, the present invention is an electro-optical device capable of guiding a light from a light-emitting element without spreading on a light-transmitting substrate to form a clear spot image, and image printing using the electro-optical device. An object of the present invention is to provide a device and an image reading device.

  In order to solve this problem, an electro-optical device according to the present invention includes a main substrate, a light emitting element formed on the main substrate, and a sealing substrate that seals the light emitting element over the main substrate. The sealing substrate has an optical waveguide penetrating from the front surface to the back surface, the optical waveguide is formed of a light transmissive material, the shape thereof is columnar, and the peripheral surface thereof is the material. It is covered with a material having a lower refractive index, and the tip surface on the light emitting element side of the tip surface covers the light emitting element.

  In this electro-optical device, light from the light emitting element travels toward a surface of the sealing substrate facing the light emitting element. Hereinafter, this surface is referred to as “back surface”, and the back surface of the back surface is referred to as “front surface”. Since the front end surface of the optical waveguide constituting the back surface of the sealing substrate covers the light emitting element, most of the light from the light emitting element enters the optical waveguide from the front end surface. Hereinafter, this tip surface is referred to as “the other tip surface”, and the other tip surface is referred to as “one tip surface”.

  When the light traveling in the optical waveguide reaches the peripheral surface of the optical waveguide, most of the light is totally reflected. The reason for this will be described. Most of the light that reaches the peripheral surface of the optical waveguide travels substantially along the direction orthogonal to the sealing substrate. On the other hand, since the optical waveguide penetrates from the front surface to the back surface of the sealing substrate, the peripheral surface is along the direction. Therefore, most of the incident angles of light on the peripheral surface are extremely large. In addition, since the refractive index of the material forming the optical waveguide is higher than the refractive index of the material covering the peripheral surface, the incident angle of light incident on the peripheral surface is the ratio of the above two refractive indexes. Total reflection occurs when the critical angle is above the critical angle. As described above, unless a material having an extreme critical angle is used, most of the light reaching the peripheral surface is totally reflected. That is, the optical waveguide functions as a core of a single optical fiber having a large diameter.

  Thus, the light incident on the optical waveguide is guided through the optical waveguide without being spread and emitted from one of the front end surfaces to form a spot image having the same shape as that of the one front end surface on the surface of the sealing substrate. The luminance distribution in the spot image is substantially uniform. This reason will be described in comparison with an embodiment using a fiber array that is a bundle of optical fibers instead of the optical waveguide. In this aspect, when the optical fiber in the vicinity of the center of the fiber array faces the central portion of the light emitting element, the back surface of the sealing substrate is positioned closer to the periphery than the light incident on the optical fiber positioned near the center. Less light is incident on the optical fiber. This uneven distribution of light quantity is maintained even in the light guiding process by the fiber array. For this reason, the brightness in the vicinity of the periphery of the spot image is lowered, and the brightness distribution in the spot image is biased. In contrast, in this electro-optical device, light from the light emitting element is guided by an optical waveguide that functions as a core of a single optical fiber having a large diameter. For this reason, the uneven distribution of the light amount on the other tip surface is alleviated on the one tip surface. This is the reason why the brightness of the spot image is substantially uniform.

As is apparent from the above description, according to this electro-optical device, it is possible to guide the light from the light-emitting element without spreading it on the light-transmitting sealing substrate, thereby forming a clear spot image.
By the way, as a method of forming the optical waveguide on the sealing substrate, a method of making a hole in the sealing substrate and filling the hole with one kind of material can be exemplified. In order to make a hole in the substrate, the substrate must be cut. However, according to this electro-optical device, it is only necessary to cut the sealing substrate instead of the main substrate that requires high utilization efficiency. Therefore, an effective effect can be obtained at the time of mass production that the utilization efficiency of the main substrate does not decrease.

  Another electro-optical device according to the present invention includes a main substrate, a light emitting element formed on the main substrate, and a sealing substrate that overlaps the main substrate and seals the light emitting element. The sealing substrate has an optical waveguide penetrating from the front surface to the back surface, the optical waveguide is formed of a light-transmitting material, and the shape thereof is tapered from the light emitting element side to the opposite side, The peripheral surface is covered with a material having a refractive index lower than that of the material, and the tip surface on the light emitting element side of the tip surface covers the light emitting element.

  This electro-optical device is different from the above-described electro-optical device in that the shape of the optical waveguide is not columnar, but is tapered from the light emitting element side to the opposite side. Therefore, according to this electro-optical device, it is possible to guide the light from the light emitting element while narrowing it in the light-transmitting sealing substrate, thereby forming a clearer spot image. This is a characteristic particularly suitable when the size of the required spot image is smaller than that of the light emitting element.

  In each of the electro-optical devices, the sealing substrate is fixed to the main substrate with a light-transmitting adhesive, and the refractive index of the material forming the optical waveguide is larger than the refractive index of the adhesive. Or may be equivalent. In this case, the light from the light emitting element passes through the adhesive and reaches the other end surface. Since the refractive index of the material forming the optical waveguide is greater than or equal to the refractive index of the adhesive, the light reaching the other tip surface is not easily reflected by the other tip surface and is likely to enter the optical waveguide. That is, more light is incident on the optical waveguide. Therefore, the brightness of the spot image can be further increased.

  Another electro-optical device according to the invention includes a main substrate and a light emitting element formed on the main substrate, the main substrate having an optical waveguide penetrating from the front surface to the back surface, The waveguide is made of a light-transmitting material, its shape is columnar, and its peripheral surface is covered with a material having a refractive index lower than that of the material. The front end surface covers the light emitting element.

  In this electro-optical device, light from the light emitting element travels toward a surface of the main substrate facing the light emitting element. Hereinafter, this surface is referred to as “back surface”, and the back surface of the back surface is referred to as “front surface”. Since the front end surface of the optical waveguide constituting the back surface of the main substrate covers the light emitting element, most of the light from the light emitting element enters the optical waveguide from the front end surface. Hereinafter, this tip surface is referred to as “the other tip surface”, and the other tip surface is referred to as “one tip surface”.

When the light traveling in the optical waveguide reaches the peripheral surface of the optical waveguide, most of the light is totally reflected. The reason is as described above. In this way, most of the light incident on the optical waveguide is guided through the optical waveguide without being spread and emitted from one of the front end surfaces, and a spot image having the same shape as that of the one front end surface is formed on the surface of the main substrate. In addition, the luminance distribution in the spot image is substantially uniform. The reason is as described above. As is clear from these facts, according to this electro-optical device, it is possible to guide the light from the light-emitting element without spreading it on the light-transmitting main substrate, thereby forming a clear spot image.
Further, according to this electro-optical device, the substrate on which the optical waveguide is formed is the main substrate on which the light emitting element is formed. Therefore, as compared with the configuration in which the optical waveguide is formed on the sealing substrate for sealing the light emitting element. Thus, the other end face can be arranged closer to the light emitting element. This contributes to an improvement in the brightness of the spot image.

Another electro-optical device according to the invention includes a main substrate and a light emitting element formed on the main substrate, the main substrate having an optical waveguide penetrating from the front surface to the back surface, The waveguide is made of a light transmissive material, and its shape is tapered from the light emitting element side to the opposite side, and its peripheral surface is covered with a material having a refractive index lower than that of the material. The front end surface on the light emitting element side of the front end surface covers the light emitting element.
According to this electro-optical device, the light from the light-emitting element can be guided while being narrowed on the light-transmitting main substrate, so that a clearer spot image can be formed. This is a characteristic particularly suitable when the size of the required spot image is smaller than that of the light emitting element.

The image printing apparatus according to the present invention includes an image carrier, a charger for charging the image carrier, and a plurality of the light emitting elements, and a plurality of the light emitting elements on a charged surface of the image carrier. Any one of the above electro-optical devices that forms a latent image by irradiating light with an element, a developing device that forms a visible image on the image carrier by attaching toner to the latent image, and the image carrier And a transfer device for transferring the visible image to another object.
As described above, according to any one of the above electro-optical devices, the light from the light-emitting element can be guided without being spread on the light-transmitting substrate to form a clear spot image. Therefore, the image printing apparatus provided with such an electro-optical device can perform high-quality printing by efficiently using light from the light emitting element.

In addition, an image reading apparatus according to the present invention converts any one of the above electro-optical devices in which a plurality of the self-light-emitting elements are arranged, and light reflected from the reading target and emitted from the self-light-emitting elements into an electric signal. A light receiving device.
As described above, according to any one of the electro-optical devices described above, it is possible to guide the light from the light-emitting element without greatly spreading on the light-transmitting substrate to form a clear spot image. Therefore, the image reading apparatus including such an electro-optical device can read an image with high quality by efficiently using light from the light emitting element.

  Embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in the following drawings. In the following drawings, the ratio of the dimensions of each part is appropriately changed from the actual one. Further, in the following sectional views, only the main part is hatched. The electro-optical device according to each of the following embodiments is used as an exposure head of an image printing apparatus that forms an electrostatic latent image on an image carrier such as a photosensitive drum. In forming an electrostatic latent image, it is necessary to irradiate light so as to cross a photosensitive surface traveling in a predetermined direction. In the following description, this predetermined direction is defined as direction X.

<A: First Embodiment>
The electro-optical device according to the first embodiment of the present invention is of a top emission type.
FIG. 1 is a plan view showing a configuration of an electro-optical device 200 according to the first embodiment of the present invention. As shown in this figure, in the electro-optical device 200, a large number of light emitting elements 205 are arranged in two rows and staggered along the direction X. These light emitting elements 205 are covered with a plate-shaped sealing substrate 230. The surface of the sealing substrate 230 is an emission surface S200, and the back surface is opposed to the light emitting element 205. The exit surface S200 is a surface on which a later-described spot image is formed, and light emitted from this surface is used to form an electrostatic latent image. A cylindrical optical waveguide 235 is formed for each light emitting element 205 in a portion of the sealing substrate 230 that overlaps the light emitting element 205.

  2 is a cross-sectional view taken along the line C-C ′ of FIG. 1. As shown in this figure, the electro-optical device 200 has a configuration in which a large number of light emitting elements 205 are sandwiched between a flat main substrate 220 and a flat sealing substrate 230. The main substrate 220 is made of glass, quartz, or plastic, and the light emitting element 205 is formed on the main substrate 220. The light emitting element 205 is an organic EL element that emits light upon receiving electric energy, and a region where the light emitting element 205 is formed is partitioned by an oxide film 260 and a partition (bank) 270 formed on the oxide film 260. . In each region, in order from the main substrate 220 side, there are an electrode 240 that functions as a cathode, a light emitting layer 210 that is formed of an organic EL material and emits light, a light-transmitting hole injection layer 250, and a transparent electrode 280 that functions as an anode. Are stacked.

  A sealing substrate 230 is overlaid and fixed on the main substrate 220 on which the light emitting element 205 is formed so as to seal the light emitting element 205 in cooperation with the main substrate 220. By this sealing, the light emitting element 205 is isolated from the outside air (especially moisture and oxygen), and its deterioration is suppressed. A light-transmitting adhesive 290 is used to fix the sealing substrate 230 to the main substrate 220. As the adhesive 290, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used.

  The types of sealing used in this field include film sealing in which the entire surface of the sealing substrate 230 is bonded to the main substrate 220 with the adhesive 290, and the peripheral portion of the sealing substrate 230 with the adhesive 290. There is cap sealing which is bonded to the main substrate 220 and provides a space defined by the sealing substrate 230 and the main substrate 220 around the light emitting element 205. In the cap sealing, a desiccant is disposed in this space. In this embodiment, film sealing is used, but cap sealing can also be used.

  The sealing substrate 230 is configured by arranging a number of optical waveguides 235 in a flat plate 231. As the flat plate 231, one formed of glass, metal, ceramic, or plastic can be used. Each optical waveguide 235 penetrates the sealing substrate 230 from its front surface to its back surface, its central axis is along the thickness direction of the sealing substrate 230, and its peripheral surface is covered with a flat plate 231. Of the front end surface of the optical waveguide 235, the one on the light emitting element 205 side is a part of the back surface of the sealing substrate 230, and the one on the opposite side is a part of the surface of the sealing substrate 230 (emission surface S200). It has become. The front end surface of the optical waveguide 235 on the light emitting element 205 side covers the light emitting layer 210 of the corresponding light emitting element 205 when viewed from the emission surface S200 side.

  The optical waveguide 235 is made of a light transmissive material. The refractive index of this material is greater than or equal to the refractive index of the adhesive 290 and is higher than the refractive index of the material forming the flat plate 231. However, in the case where the requirement for the utilization efficiency of light from the light emitting layer 210 is not strict, the refractive index of the material forming the optical waveguide 235 does not have to be greater than or equal to the refractive index of the adhesive 290.

  The optical waveguide 235 is fixed to the flat plate 231. This fixing method is arbitrary, but care must be taken when using a method in which the peripheral surface of the optical waveguide 235 does not contact the flat plate 231. As such a method, a method of fixing the optical waveguide 235 to the flat plate 231 with an adhesive can be considered. In this case, it is necessary to use an adhesive having a lower refractive index than the material forming the optical waveguide 235. That is, the peripheral surface of the optical waveguide 235 must be covered with a material having a refractive index lower than that of the material.

  FIG. 3 is a cross-sectional view for explaining the optical action in the electro-optical device 200. In the electro-optical device 200, when a voltage is applied by the electrode 240 and the transparent electrode 280, the light emitting layer 210 sandwiched between them emits light. Most of the light traveling from the light emitting layer 210 to the sealing substrate 230 travels straight along a direction orthogonal to the sealing substrate 230 and passes through the hole injection layer 250, the transparent electrode 280, and the adhesive 290 to be sealed. It reaches the back surface of the substrate 230, more specifically, the front end surface of the optical waveguide 235 on the light emitting element 205 side. Since the refractive index of the material forming the optical waveguide 235 is greater than or equal to the refractive index of the adhesive 290, the light reaching the distal end surface is not easily reflected by the distal end surface and is likely to enter the optical waveguide 235. As a result, most of the light reaching the tip surface enters the optical waveguide 235 and travels through the optical waveguide 235.

  When the light traveling in the optical waveguide 235 reaches the peripheral surface of the optical waveguide 235, most of the light is totally reflected. That is, the optical waveguide 235 functions as a core of a single optical fiber having a large diameter, and guides incident light. Total reflection occurs because the angle between the traveling direction of light reaching the peripheral surface of the optical waveguide 235 and the peripheral surface is usually extremely small. In other words, it is normal that the incident angle to the peripheral surface of the optical waveguide 235 is extremely large. More specifically, it is as follows.

  Since the refractive index of the material forming the optical waveguide 235 is higher than the refractive index of the material covering the peripheral surface thereof (for example, the material forming the flat plate 231 or the adhesive), It can be totally reflected at the surface. However, for total reflection, the incident angle needs to be greater than or equal to the critical angle determined based on the ratio of the two refractive indexes. However, as described above, it is normal that the incident angle to the peripheral surface is extremely large. Therefore, unless a material having an extreme critical angle is used, most of the light reaching the peripheral surface is totally reflected. Become. Needless to say, it is desirable to determine a material for forming the optical waveguide 235 and a material covering the peripheral surface so that a sufficiently large amount of light is totally reflected.

Thus, the light traveling in the optical waveguide 235 is guided to the optical waveguide 235 and is emitted from the front end surface on the emission surface S200 side. As a result, a spot image (light image) is formed on the exit surface S200.
FIG. 4 is a view showing a spot image formed by the electro-optical device 200. The shape, size, and formation position of the spot image coincide with the tip surface of the optical waveguide 235 on the exit surface S200 side. In addition, the brightness distribution of the spot image is substantially uniform.

  As described above, according to the electro-optical device 200, a clear spot image can be formed by guiding the electro-optical device 200 without spreading on the sealing substrate 230 that transmits light from the light emitting layer 210. Further, since the light from the light emitting layer 210 is not reflected at the boundary surface between the adhesive 290 and the optical waveguide 235, the light use efficiency from the light emitting layer 210 can be further improved. In addition, since the optical waveguide is formed on a sealing substrate that does not require as high surface accuracy as the main substrate, it is easier to manufacture than a bottom emission type electro-optical device in which the optical waveguide is formed on the main substrate. Become.

Next, an example of a method for manufacturing the electro-optical device 200 will be described.
FIG. 5 is a diagram illustrating a first step in an example of a method for manufacturing the electro-optical device 200. As shown in this figure, first, a large number of cylindrical holes are formed in the flat plate 231. Since these holes are filled later to become the optical waveguide 235, the holes are drilled so that the front end surface can cover the light emitting layer 210. As a method for making a hole, a known method suitable for the material forming the flat plate 231 can be adopted. For example, when the flat plate 231 is made of glass, a method of etching with hydrofluoric acid to make a hole can be employed. In addition, for example, when the flat plate 231 can be formed from an ultraviolet curable resin, a method of applying a UV ray to a part of the flat plate 231 through a mask to cure and cutting a non-cured portion may be employed. .

  FIG. 6 is a view showing the next step of FIG. As shown in this figure, the sealing substrate 230 in which the optical waveguide 235 is formed is formed by filling the holes. This hole filling is an operation of putting a resin, which is a material for forming the optical waveguide 235, into the opened holes so that the front surface and the back surface of the sealing substrate 230 are flush with each other. As a hole filling method, there are a method of inserting a resin with a squeegee, a method of applying with a dispenser such as an ink jet, and the like. Note that when the sealing substrate 230 is formed by filling a hole, the material for forming the optical waveguide 235 is limited to resin, but this is not the case when the sealing substrate 230 is formed by another method.

FIG. 7 is a view showing the next step of FIG. As shown in this figure, a large number of light emitting elements 205 are formed on the main substrate 220.
FIG. 8 is a view showing the next step of FIG. As shown in this figure, an adhesive 290 is applied to the surface of the main substrate 220 on which the light emitting element 205 is formed (or the back surface of the sealing substrate 230), and the sealing substrate 230 is applied to the main substrate 220 by the adhesive 290. Glue and fix. At this time, the main substrate 220 and the sealing substrate 230 are disposed so that the front end surfaces of the respective optical waveguides 235 facing the main substrate 220 cover the light emitting layers 210 of the corresponding light emitting elements 205. Thus, the electro-optical device 200 is completed.

  As described above, this manufacturing method requires cutting of the substrate. However, what is cut is the sealing substrate, and the main substrate is not cut. Therefore, there is an effective effect at the time of mass production that the utilization efficiency of the main substrate that requires high utilization efficiency is not lowered.

<Second Embodiment>
The electro-optical device according to the second embodiment of the present invention is of a bottom emission type.
FIG. 9 is a cross-sectional view illustrating a configuration of an electro-optical device 300 according to the second embodiment of the present invention. The electro-optical device 300 is greatly different from the electro-optical device 200 of FIG. 2 in that an optical waveguide is formed on the main substrate, not the sealing substrate. Due to this difference, in the electro-optical device 300, the light emitting element 305 is used instead of the light emitting element 205, the flat plate 231 is used as it is as a sealing substrate, and the main substrate 320 is used instead of the main substrate 220. ing.

  Further, the back surface of the main substrate 320 on which the light emitting element 305 is formed is an emission surface S300, and light used for forming the electrostatic latent image is emitted from the emission surface S300. The light emitting element 305 is different from the light emitting element 205 only in that it has a transparent electrode 340 functioning as an anode instead of the electrode 240 functioning as a cathode, and an electrode 380 functioning as a cathode instead of the transparent electrode 280 functioning as an anode. is there.

  The main substrate 320 is configured by forming a cylindrical optical waveguide 325 in a flat plate 321 for each light emitting element 305. Each optical waveguide 325 overlaps the corresponding light emitting element 305. As the flat plate 321, one formed from glass, quartz, or plastic can be used. Each optical waveguide 325 penetrates the main substrate 320 from the front surface to the back surface, the central axis is along the thickness direction of the main substrate 320, and the peripheral surface is covered with a flat plate 321. Of the front end surface of the optical waveguide 325, the one on the light emitting element 305 side is a part of the back surface of the main substrate 320, and the one on the opposite side is a part of the surface of the main substrate 320 (emission surface S300). Yes.

  Further, the tip surface of the light guide 325 on the light emitting element 305 side covers the light emitting layer 210 of the corresponding light emitting element 305 when viewed from the emission surface S300 side. The optical waveguide 325 is made of a light transmissive material. The refractive index of this material is higher than the refractive index of the material forming the flat plate 321. The optical waveguide 325 is fixed to the flat plate 321 and its peripheral surface is covered with a material having a refractive index lower than that of the material.

  FIG. 10 is a cross-sectional view for explaining the optical action in the electro-optical device 300. In the electro-optical device 300, when a voltage is applied by the transparent electrode 340 and the electrode 380, the light emitting layer 210 sandwiched therebetween emits light. Most of the light traveling from the light emitting layer 210 to the main substrate 320 travels straight along a direction orthogonal to the main substrate 320, passes through the transparent electrode 340, and reaches the back surface of the main substrate 320, more specifically, an optical waveguide. 325 reaches the front end surface of the light emitting element 305 side. The light that reaches the tip surface enters the optical waveguide 325 and travels through the optical waveguide 325. Since the optical waveguide 325 functions as the core of a single optical fiber having a large diameter, most of the light incident on the optical waveguide 325 is guided to the optical waveguide 325 and emitted from the distal end surface on the emission surface S300 side.

According to the electro-optical device 300, the same effect as the electro-optical device 200 can be obtained. However, since the optical waveguide is formed on the main substrate, the effect obtained by forming the optical waveguide on the sealing substrate cannot be obtained.
Further, in the electro-optical device 300, since the optical waveguide 325 is formed on the main substrate 320, the distance from the light emitting layer to the optical waveguide is shorter than that of the electro-optical device 200. This contributes to an improvement in the brightness of the spot image.

<Third Embodiment>
The electro-optical device according to the third embodiment of the present invention is of a bottom emission type.
FIG. 11 is a cross-sectional view showing a configuration of an electro-optical device 400 according to the third embodiment of the present invention. The electro-optical device 400 is greatly different from the electro-optical device 300 in FIG. 9 in the shape of an optical waveguide. Due to this difference, the electro-optical device 400 uses the main substrate 420 instead of the main substrate 320. In addition, the back surface of the main substrate 420 on which the light emitting element 305 is formed is an emission surface S400, and light used for forming the electrostatic latent image is emitted from the emission surface S400.

  The main substrate 420 is formed with a truncated cone-shaped optical waveguide 425 instead of the optical waveguide 325. The optical waveguide 425 is different from the optical waveguide 325 only in its shape. Further, the optical waveguide 425 penetrates from the front surface to the back surface of the main substrate 420, and of the front end surfaces, the wider front end surface on the light emitting element 305 side is a part of the back surface of the main substrate 420, The narrower tip surface on the opposite side is a part of the surface of the main substrate 420 (the exit surface S400). Further, the wider end surface of the optical waveguide 425 covers the light emitting layer 210 of the corresponding light emitting element 305 when viewed from the emission surface S400 side.

According to the electro-optical device 400, the same effect as the electro-optical device 300 can be obtained. However, only a combination of the material forming the optical waveguide 425 and the material covering the peripheral surface of the optical waveguide 425 is required to totally reflect most of the light that travels in the optical waveguide 425 and reaches the peripheral surface. In addition, it is necessary to pay attention to the inclination angle of the peripheral surface of the optical waveguide 425.
Further, according to the electro-optical device 400, the shape of the optical waveguide 425 is tapered from the light emitting element 305 side to the opposite side, so that the light from the light emitting layer 210 can be guided in the main substrate 420 while being narrowed. . This increases the brightness of the spot image. Further, it is suitable for use when the required spot image size is narrower than the light emitting surface of the light emitting layer 210.

Next, an example of a method for manufacturing the electro-optical device 400 will be described.
FIG. 12 is a diagram illustrating a first step in an example of a method for manufacturing the electro-optical device 400. As shown in this figure, first, a large number of truncated cone-shaped holes are made in the flat plate 321. As a method for making a hole, for example, there is a method of making a hole by etching with hydrofluoric acid. When a hole is drilled by this method, the shape is usually a truncated cone shape. Therefore, in this step, the truncated cone-shaped hole can be efficiently drilled by utilizing this property. Note that the above-described perforation is substantially the same as the size of the required spot image on the narrower end surface of the truncated cone, and the larger end surface can cover the light emitting layer 210. It is done to be the size.

  FIG. 13 is a view showing the next step of FIG. As shown in this figure, the above-described hole filling is performed to create a main substrate 420 on which an optical waveguide 425 is formed. Since the hole has a truncated cone shape, a truncated cone-shaped optical waveguide 425 is formed by filling the hole. That is, even if the end face that appears when a hole is made in the flat plate 321 is inclined, the optical waveguide 425 can be formed by filling the hole without eliminating this inclination. This is an effective effect during mass production.

  FIG. 14 is a view showing the next step of FIG. As shown in this figure, a large number of light emitting elements 305 are formed on a main substrate 420. At this time, each light emitting element 305 is disposed so as to be covered with a wide end surface of the corresponding optical waveguide 425. The subsequent steps are the same as those described above for the electro-optical device 200.

<Fourth embodiment>
The electro-optical device according to the fourth embodiment of the invention is of a top emission type.
FIG. 15 is a cross-sectional view showing the configuration of an electro-optical device 500 according to the fourth embodiment of the invention. The electro-optical device 500 is greatly different from the electro-optical device 200 of FIG. 2 in the shape of an optical waveguide. Due to this difference, the electro-optical device 500 uses a sealing substrate 530 instead of the sealing substrate 230. The surface on the back side of the surface of the sealing substrate 530 facing the light emitting element 205 is an emission surface S500, and light used for forming the electrostatic latent image is emitted from the emission surface S500.

  In the sealing substrate 530, a truncated cone-shaped optical waveguide 535 is formed instead of the optical waveguide 235. The optical waveguide 535 is different from the optical waveguide 235 only in its shape. Further, the optical waveguide 535 penetrates from the front surface to the back surface of the sealing substrate 530, and among the front end surfaces, the wider front end surface on the light emitting element 205 side becomes a part of the back surface of the sealing substrate 530. The narrower end surface on the opposite side is a part of the surface (outgoing surface S500) of the sealing substrate 530. Further, the wider end surface of the optical waveguide 535 covers the light emitting layer 210 of the corresponding light emitting element 205 when viewed from the emission surface S500 side.

According to the electro-optical device 500, the same effect as the electro-optical device 200 can be obtained. Note that points to be noted and further effects are the same as those described for the electro-optical device 400, and thus description thereof is omitted.
The method for manufacturing the electro-optical device 500 is obvious from the method for manufacturing the electro-optical device 200 and the method for manufacturing the electro-optical device 400. Since the direction of the optical waveguide 535 is opposite to the direction of the optical waveguide 425 of the electro-optical device 400, the sealing substrate 530 created by filling the holes is reversed and bonded to the main substrate 220.

<Modification>
In the above-described embodiment, the columnar or truncated cone-shaped optical waveguide is exemplified, but the shape of the optical waveguide is not limited thereto. For example, it may be a prismatic shape, or may be a columnar shape with a semicircular tip surface. That is, it can be an arbitrary column shape. For example, it may be a truncated pyramid shape or an arbitrary tapered shape. However, regardless of the shape, it must be ensured that most of the light traveling in the optical waveguide is totally reflected on its peripheral surface.
In the above-described embodiment, an example in which an organic EL element is used as a light emitting element has been described. However, an inorganic EL element may be used.

<Application example>
As described above, the electro-optical device according to the above-described embodiment is used as an exposure head of an image printing apparatus that forms an electrostatic latent image on an image carrier such as a photosensitive drum. When used as an exposure head, the method of use is roughly divided into two. One is a form in which the light from the exit surface is directly irradiated to the image carrier, and the other is a form in which the light from the exit surface is irradiated to the image carrier through the converging lens array. In the former form, the electro-optical device is arranged so that the exit surface is close to or in contact with the image carrier. The latter form will be described with reference to the drawings.

  FIG. 16 is a perspective view showing an outline of an electro-optical device 600 having a converging lens array 610. This electro-optical device 600 forms an electrostatic latent image by irradiating the photosensitive drum 620 rotating in a predetermined direction, and includes the electro-optical device 200 according to the first embodiment as a light source. . The electro-optical device 200 is attached to a housing of an image printing apparatus (not shown) so that the arrangement direction (direction X) of the light emitting elements 205 is aligned with the rotation axis direction of the photosensitive drum 620. The electro-optical device 200 is only an example, and any electro-optical device according to another embodiment may be used instead.

  FIG. 17 is a perspective view showing the configuration of the condensing lens array 610. The condensing lens array 610 includes a plurality of gradient index lenses 615 arranged in two rows and in a staggered manner, and the electro-optic is arranged so that the arrangement direction is aligned with the arrangement direction of the light emitting elements 205 of the electro-optical device 200. It is fixed to the device 200. As the condensing lens array 610, for example, there is SLA (Selfoc Lens Array) available from Nippon Sheet Glass Co., Ltd. (Selfoc \ SELFOC is a registered trademark of Nippon Sheet Glass Co., Ltd.).

  The condensing lens array 610 is disposed between the electro-optical device 200 and the photosensitive drum 620. The distance from the exit surface S200 of the electro-optical device 200 to the condensing lens array 610 and the distance from the condensing lens array 610 to the photosensitive drum 620 are both L0. With such an arrangement, light from the exit surface S200 of the electro-optical device 200 is guided by the condensing lens array 610 and reaches the photosensitive drum 620, and is the same as the spot image formed on the exit surface S200. Are formed on the outer peripheral surface of the photosensitive drum 620.

<Image printing device>
Next, the overall configuration of the image printing apparatus according to the present invention will be described with reference to FIG.
FIG. 18 is a longitudinal sectional view showing an example of an image forming apparatus using the electro-optical device according to the above-described embodiment or application example as an exposure head. This image printing apparatus is a tandem type full-color image printing apparatus using a belt intermediate transfer body system.

  In this image printing apparatus, four organic EL array exposure heads 10K, 10C, 10M, and 10Y having the same configuration are replaced with four photosensitive drums (image carriers) 110K, 110C, 110M, and 110Y having the same configuration. The exposure positions are respectively arranged. The organic EL array exposure heads 10K, 10C, 10M, and 10Y are electro-optical devices (200, 300, 400, 500, or 600) according to the above-described embodiments or application examples.

  As shown in FIG. 18, this image printing apparatus is provided with a driving roller 121 and a driven roller 122. An endless intermediate transfer belt 120 is wound around these rollers 121 and 122, and an arrow indicates As shown, the periphery of the rollers 121 and 122 is rotated. Although not shown, tension applying means such as a tension roller that applies tension to the intermediate transfer belt 120 may be provided.

  Around the intermediate transfer belt 120, four photosensitive drums 110K, 110C, 110M, and 110Y each having a photosensitive layer on the outer peripheral surface are arranged at a predetermined interval. The subscripts K, C, M, and Y mean that they are used to form black, cyan, magenta, and yellow visible images, respectively. The same applies to other members. The photosensitive drums 110K, 110C, 110M, and 110Y are rotationally driven in synchronization with the driving of the intermediate transfer belt 120.

  Around each photosensitive drum 110 (K, C, M, Y), a corona charger 111 (K, C, M, Y), an organic EL array exposure head 10 (K, C, M, Y), and , Developing devices 114 (K, C, M, Y) are arranged. The corona charger 111 (K, C, M, Y) uniformly charges the outer peripheral surface of the corresponding photosensitive drum 110 (K, C, M, Y). The organic EL array exposure head 10 (K, C, M, Y) writes an electrostatic latent image on the charged outer peripheral surface of the photosensitive drum. Each organic EL array exposure head 10 (K, C, M, Y) has a plurality of light emitting elements arranged along the bus (main scanning direction) of the photosensitive drum 110 (K, C, M, Y). Installed. The writing of the electrostatic latent image is performed by irradiating the photosensitive drum with light by a plurality of light emitting elements. The developing device 114 (K, C, M, Y) forms a visible image, that is, a visible image on the photosensitive drum by attaching toner as a developer to the electrostatic latent image.

  The black, cyan, magenta, and yellow developed images formed by the four-color single-color image forming station are sequentially transferred onto the intermediate transfer belt 120 to be superimposed on the intermediate transfer belt 120. As a result, a full-color image is obtained. Four primary transfer corotrons (transfer devices) 112 (K, C, M, Y) are arranged inside the intermediate transfer belt 120. The primary transfer corotron 112 (K, C, M, Y) is disposed in the vicinity of the photosensitive drum 110 (K, C, M, Y), and the photosensitive drum 110 (K, C, M, Y). The electrostatic image is electrostatically attracted from the toner image to transfer the visible image to the intermediate transfer belt 120 passing between the photosensitive drum and the primary transfer corotron.

  A sheet 102 as an object on which an image is to be finally formed is fed one by one from the sheet feeding cassette 101 by the pickup roller 103, and between the intermediate transfer belt 120 and the secondary transfer roller 126 in contact with the driving roller 121. Sent to the nip. The full-color visible image on the intermediate transfer belt 120 is secondarily transferred to one side of the sheet 102 by the secondary transfer roller 126 and fixed on the sheet 102 through the fixing roller pair 127 as a fixing unit. . Thereafter, the sheet 102 is discharged onto a paper discharge cassette formed in the upper part of the apparatus by a paper discharge roller pair 128.

Next, another embodiment of the image printing apparatus according to the present invention will be described with reference to FIG.
FIG. 19 is a longitudinal sectional view of another image forming apparatus using the electro-optical device according to the above-described embodiment or application example as an exposure head. This image printing apparatus is a rotary development type full-color image printing apparatus using a belt intermediate transfer body system. As shown in FIG. 19, around the photosensitive drum 165, a corona charger 168, a rotary developing unit 161, an organic EL array exposure head 167, and an intermediate transfer belt 169 are provided.

  The corona charger 168 uniformly charges the outer peripheral surface of the photosensitive drum 165. The organic EL array exposure head 167 writes an electrostatic latent image on the charged outer peripheral surface of the photosensitive drum 165. The organic EL array exposure head 167 is an electro-optical device (200, 300, 400, 500, or 600) according to each of the embodiments or application examples described above, and a plurality of light emitting elements is a bus ( It is installed so as to be arranged along the main scanning direction. The electrostatic latent image is written by irradiating the photosensitive drum 165 with light from these light emitting elements.

  The developing unit 161 is a drum in which four developing units 163Y, 163C, 163M, and 163K are arranged at an angular interval of 90 °, and can rotate counterclockwise about the shaft 161a. The developing units 163Y, 163C, 163M, and 163K supply yellow, cyan, magenta, and black toners to the photosensitive drum 165, respectively, and attach the toner as a developer to the electrostatic latent image, thereby the photosensitive drum 165. A visible image, that is, a visible image is formed.

  The endless intermediate transfer belt 169 is wound around a driving roller 170a, a driven roller 170b, a primary transfer roller 166, and a tension roller, and is rotated around these rollers in a direction indicated by an arrow. The primary transfer roller 166 transfers the visible image to the intermediate transfer belt 169 that passes between the photosensitive drum and the primary transfer roller 166 by electrostatically attracting the visible image from the photosensitive drum 165.

  Specifically, in the first rotation of the photosensitive drum 165, an electrostatic latent image for a yellow (Y) image is written by the exposure head 167, and a developed image of the same color is formed by the developing unit 163Y. The image is transferred to the transfer belt 169. Further, in the next rotation, an electrostatic latent image for a cyan (C) image is written by the exposure head 167, and a developed image of the same color is formed by the developing device 163C. The intermediate transfer is performed so as to overlap the yellow developed image. Transferred to the belt 169. Then, during the four rotations of the photosensitive drum 165, yellow, cyan, magenta, and black visible images are sequentially superimposed on the intermediate transfer belt 169. As a result, a full-color visible image is formed on the transfer belt 169. It is formed. When images are finally formed on both sides of a sheet as an object on which an image is to be formed, the same color images of the front and back surfaces are transferred to the intermediate transfer belt 169, and then the front and back surfaces are transferred to the intermediate transfer belt 169. A full-color visible image is obtained on the intermediate transfer belt 169 by transferring the visible image of the next color.

  The image printing apparatus is provided with a sheet conveyance path 174 through which a sheet is passed. The sheets are picked up one by one from the paper feed cassette 178 by the pick-up roller 179, advanced through the sheet transport path 174 by the transport roller, and between the intermediate transfer belt 169 and the secondary transfer roller 171 in contact with the drive roller 170a. Pass through the nip. The secondary transfer roller 171 transfers the developed image to one side of the sheet by electrostatically attracting a full-color developed image from the intermediate transfer belt 169 collectively. The secondary transfer roller 171 can be moved closer to and away from the intermediate transfer belt 169 by a clutch (not shown). The secondary transfer roller 171 is brought into contact with the intermediate transfer belt 169 when a full-color visible image is transferred onto the sheet, and is separated from the secondary transfer roller 171 while the visible image is superimposed on the intermediate transfer belt 169.

  The sheet on which the image has been transferred as described above is conveyed to the fixing device 172 and is passed between the heating roller 172a and the pressure roller 172b of the fixing device 172, whereby the visible image on the sheet is fixed. The sheet after the fixing process is drawn into the discharge roller pair 176 and proceeds in the direction of arrow F. In the case of double-sided printing, after most of the sheet passes through the paper discharge roller pair 176, the paper discharge roller pair 176 is rotated in the reverse direction and introduced into the double-sided printing conveyance path 175 as indicated by an arrow G. The Then, the visible image is transferred to the other surface of the sheet by the secondary transfer roller 171, the fixing process is performed again by the fixing device 172, and then the sheet is discharged by the discharge roller pair 176.

  Since the image printing apparatus illustrated in FIGS. 18 and 19 uses the organic EL element as writing means (exposure means), the apparatus can be made smaller than when a laser scanning optical system is used. it can. Note that the light-emitting device of the present invention can also be employed in electrophotographic image printing apparatuses other than those exemplified above. For example, an image printing apparatus of a type that directly transfers a visible image from a photosensitive drum to a sheet without using an intermediate transfer belt, an image printing apparatus that forms a monochrome image, or a photosensitive belt instead of the photosensitive drum. The electro-optical device according to the present invention can also be applied to the image printing apparatus provided.

<Image reading device>
Further, the electro-optical device according to the above-described embodiment can be used as a line-type optical head for irradiating light to a reading target in the image reading device. Examples of the image reading apparatus include a scanner, a reading portion of a copying machine, a reading portion of a facsimile, a barcode reader, and a two-dimensional image code reader that reads a two-dimensional image code such as a QR code (registered trademark).

  FIG. 20 is a longitudinal sectional view illustrating an example of an image reading apparatus using the electro-optical device 200, 300, 400, or 500 as a line type optical head 706. A flat platen glass 702 is provided on the upper portion of the cabinet 701 of the image reading apparatus, and a document 703 is placed on the platen glass 702 with its image surface facing downward. Then, a platen cover (not shown) presses the document 703 toward the platen glass 702.

  Inside the cabinet 701, a high speed carriage 704 and a low speed carriage 705 are arranged so as to be movable in the horizontal direction. An optical head 706 for irradiating the original 703 and a reflecting mirror 707 are mounted on the high-speed carriage 704, and two reflecting mirrors 708 and 709 are mounted on the low-speed carriage 705. These optical head 706 and reflecting mirrors 707, 708, and 709 extend in the direction perpendicular to the paper surface (main scanning direction) in FIG. The optical head 706 is installed so that the arrangement direction of the plurality of EL elements 14 is along the main scanning direction.

  A document reader 710 is arranged at a fixed position inside the cabinet 701. The document reader 710 includes an imaging lens 712 and a line sensor (light receiving device) 713 composed of a large number of photosensitive pixels (charge coupled devices). The line sensor 713 extends in the direction perpendicular to the paper surface (main scanning direction) in FIG. 13, and is arranged so that the arrangement direction of the plurality of photosensitive pixels is along the main scanning direction.

  Light emitted from the optical head 706 passes through the platen glass 702 and is reflected by the lower surface of the document 703. Reflected light from the original 703 is transmitted through the platen glass 702, reflected by the reflecting mirrors 707 to 709, and then imaged by the line sensor 713 by the imaging lens 712. The high-speed carriage 704 moves in the horizontal direction so that the entire surface of the original 703 is irradiated with the optical head 706, and the low-speed carriage 705 moves at half the speed of the high-speed carriage 704 and reaches the line sensor 713 from the original 703. The length of the reflected light path is kept constant.

  The image reading apparatus to which the electro-optical device 200, 300, 400, or 500 can be applied has been described above. However, these electro-optical devices can also be applied to other image reading devices, and such image reading is possible. The device is within the scope of the present invention. For example, the light receiving device may move together with the electro-optical device as the illumination device, or both the light receiving device and the electro-optical device may be fixed and the original or the reading target may be moved and read.

1 is a plan view showing a configuration of an electro-optical device 200 according to a first embodiment of the present invention. It is C-C 'sectional drawing of FIG. 5 is a cross-sectional view for explaining an optical action in the electro-optical device 200. FIG. FIG. 4 is a diagram showing a spot image formed by the electro-optical device 200. 6 is a diagram illustrating a first step in an example of a method for manufacturing the electro-optical device 200. FIG. It is a figure which shows the next process of FIG. It is a figure which shows the next process of FIG. It is a figure which shows the next process of FIG. FIG. 6 is a cross-sectional view illustrating a configuration of an electro-optical device 300 according to a second embodiment of the invention. 6 is a cross-sectional view for explaining an optical action in the electro-optical device 300. FIG. FIG. 10 is a cross-sectional view illustrating a configuration of an electro-optical device 400 according to a third embodiment of the invention. 6 is a diagram illustrating a first step in an example of a method for manufacturing the electro-optical device 400. FIG. FIG. 13 is a diagram showing a step subsequent to FIG. 12. It is a figure which shows the next process of FIG. FIG. 10 is a cross-sectional view illustrating a configuration of an electro-optical device 500 according to a fourth embodiment of the invention. 1 is a perspective view showing an outline of an electro-optical device 600 having a converging lens array 610. FIG. It is a perspective view which shows the structure of the condensing lens array 610. FIG. It is a longitudinal cross-sectional view which shows an example of the image forming apparatus which used the electro-optical apparatus which concerns on embodiment mentioned above or an application example as an exposure head. It is a longitudinal cross-sectional view of another image forming apparatus using the electro-optical device according to the embodiment or the application example described above as an exposure head. 1 is a longitudinal sectional view showing an example of an image reading apparatus using an electro-optical device 200, 300, 400 or 500 as a line type optical head 706. FIG. It is sectional drawing which shows an example of the conventional electro-optical apparatus of a bottom emission type. It is sectional drawing which shows an example of another conventional electro-optical apparatus. It is a figure which shows the spot image formed with the electro-optical apparatus of FIG.

Explanation of symbols

200, 300, 400, 500, 600: electro-optical device, 205: light emitting element, 210: light emitting layer, 220: main substrate, 230: sealing substrate, 290: adhesive, S200: emission surface.

Claims (7)

A main board;
A light emitting device formed on the main substrate;
A sealing substrate that overlaps the main substrate and seals the light emitting element,
The sealing substrate has an optical waveguide penetrating from the front surface to the back surface,
The optical waveguide is made of a light-transmitting material, has a columnar shape, and its peripheral surface is covered with a material having a refractive index lower than that of the material. An electro-optical device characterized in that a front end surface of the side covers the light emitting element. A main board;
A light emitting device formed on the main substrate;
A sealing substrate that overlaps the main substrate and seals the light emitting element,
The sealing substrate has an optical waveguide penetrating from the front surface to the back surface,
The optical waveguide is made of a light-transmitting material, and its shape is tapered from the light emitting element side to the opposite side, and its peripheral surface is covered with a material having a refractive index lower than that of the material. An electro-optical device characterized in that a tip surface on the light emitting element side of the tip surface covers the light emitting element. The sealing substrate is fixed to the main substrate by a light transmissive adhesive,
The electro-optical device according to claim 1, wherein a refractive index of a material forming the optical waveguide is greater than or equal to a refractive index of the adhesive. A main board;
A light emitting element formed on the main substrate,
The main substrate has an optical waveguide penetrating from the front surface to the back surface,
The optical waveguide is made of a light-transmitting material, has a columnar shape, and its peripheral surface is covered with a material having a refractive index lower than that of the material. An electro-optical device characterized in that a front end surface of the side covers the light emitting element. A main board;
A light emitting element formed on the main substrate,
The main substrate has an optical waveguide penetrating from the front surface to the back surface,
The optical waveguide is made of a light-transmitting material, and its shape is tapered from the light emitting element side to the opposite side, and its peripheral surface is covered with a material having a lower refractive index than the material. An electro-optical device characterized in that a tip surface on the light emitting element side of the tip surface covers the light emitting element. An image carrier;
A charger for charging the image carrier;
6. The electro-optical device according to claim 1, wherein a plurality of the light emitting elements are arranged and a latent image is formed by irradiating light on the charged surface of the image carrier with the plurality of light emitting elements. Equipment,
A developing unit that forms a visible image on the image carrier by attaching toner to the latent image;
An image printing apparatus comprising: a transfer device that transfers the visible image from the image carrier to another object. The electro-optical device according to claim 1, wherein a plurality of the self-light-emitting elements are arranged;
An image reading apparatus comprising: a light receiving device that converts light emitted from the light-emitting element and reflected by a reading target into an electric signal.

Images