JP4581692B2 - ORGANIC LIGHT EMITTING DIODE DEVICE, IMAGE FORMING DEVICE, AND IMAGE READING DEVICE - Google Patents

Description

The present invention relates to an electro-optical device including a self-luminous element, and an image forming apparatus and an image reading device including the electro-optical device.

In recent years, organic light emitting diodes (Organic Light Emitting), called organic electroluminescent elements and light emitting polymer elements, are the next generation of light emitting devices that can replace liquid crystal elements.
A diode (hereinafter abbreviated as “OLED” where appropriate) is drawing attention. OLED element
For example, as disclosed in Patent Document 1 and Patent Document 2, it is used as a display device.

In addition, an electrophotographic image forming apparatus has been developed that uses a line head in which a large number of OLED elements are arranged as exposure means, that is, a latent image writer. In such a line head, a plurality of pixel circuits including an OLED element and a transistor for driving the OLED element are arranged. For example, Patent Document 3 and Patent Document 4 disclose such a line head.

JP 2000-58255 A JP 2001-343933 A JP 11-27469 A JP 2001-130048 A

There is a high demand for miniaturization of an electro-optical device including a self-luminous element such as an OLED element. For example, in an electrophotographic image forming apparatus that uses this type of electro-optical device as a line head for writing a latent image, a latent image is written on an image carrier in a limited space between a charger and a developer. There is a need. For this reason, when the line head is large, the line head must be disposed at a position away from the image carrier, and the entire image forming apparatus is also increased in size. By downsizing the electro-optical device, there is a possibility of contributing to downsizing of the entire image forming apparatus.

However, in the conventional electro-optical device, the arrangement of the constituent elements has been a limitation of downsizing. For example, in the techniques of Patent Document 1 and Patent Document 4, an OLED is formed on a substrate on which an OLED element is formed.
Since circuit elements for driving or controlling the elements are arranged, it is necessary to use a substrate having a large area.

Accordingly, the present invention provides an electro-optical device that can be easily reduced in size, and an image forming apparatus and an image reading device including the electro-optical device.

In order to solve the above problems, an organic light emitting diode device according to the present invention includes a substrate on which a first connection terminal is formed, a plurality of organic light emitting diode elements formed on the first surface of the substrate, and at least A sealing body disposed on the first surface including the organic light emitting diode element and formed of any one of glass, metal, ceramic, or plastic, and for driving or controlling the organic light emitting diode element A circuit element having a plurality of second connection terminals formed using a semiconductor, a wiring board composed of a multilayer substrate in which wiring layers and insulating layers are alternately stacked, and at least the circuit element and the organic light emitting element A power line for supplying power to one of the diode elements, and the circuit element is on a third surface opposite to the second surface of the sealing body facing the first surface. The circuit element is disposed and at least one of the plurality of second connection terminals is electrically connected to the first connection terminal by a metal bonding wire and faces the third surface. The wiring board is disposed in a region that does not overlap the region on the third surface where the circuit element is disposed, and the power supply line is formed on the fifth surface opposite to the fourth surface. At least one of the plurality of second connection terminals that is disposed on the seventh surface opposite to the sixth surface of the wiring board opposite to the third surface and is not connected to the first connection terminal. One is characterized in that it is electrically connected to the power line by a metal bonding wire.
The electro-optical device according to the present invention includes a substrate, a plurality of self-light-emitting elements formed on the substrate, and a seal attached to the substrate so as to seal the self-light-emitting element in cooperation with the substrate. A body, a circuit for driving or controlling the self-light-emitting element, a wiring board attached to the sealing body, and power supply to at least one of the circuit and the self-light-emitting element provided on the wiring board Power supply line. A power supply line for supplying power to a large number of self-luminous elements and circuits has a large cross-sectional area because a large current needs to flow. When such a power supply line is provided on a substrate on which a self-light emitting element is formed, a substrate having a large area is required. However, according to this arrangement, such a power supply line overlaps the sealing body that seals the self-light-emitting element, so that the area of the substrate on which the self-light-emitting element is formed can be reduced. Accordingly, the substrate can be saved and the entire apparatus including the electro-optical device can be reduced in size.

In a preferred embodiment, the circuit is attached to the sealing body. According to this arrangement, the circuit that drives or controls the self-light emitting element overlaps the sealing body that seals the self-light emitting element, so that the area of the substrate on which the self light emitting element is formed can be further reduced. .

In another preferred embodiment, the power line is separated from the substrate and the sealing body. As a method for electrically connecting the power supply line to the circuit or the self-luminous element, there is a method of applying heat to the power supply line. Since the self-luminous element is vulnerable to heat, if the heat of the power line is transmitted to the self-luminous element, the self-luminous element may be damaged or deteriorated. Accordingly, the manufacturing process is limited when the above-described method is adopted in manufacturing a general electro-optical device. But according to this arrangement,
Since it is difficult for the heat of the power line to be transmitted to the self-luminous element, the degree of freedom in the manufacturing process can be increased.

In another preferred embodiment, the circuit is formed using a semiconductor, and part or all of the circuit is covered with a light shielding film. A circuit using a semiconductor can malfunction when exposed to light. However, according to this embodiment, since the amount of light reaching the circuit is reduced, the probability that the circuit malfunctions can be reduced.

An image forming apparatus according to the present invention includes an image carrier, a charger for charging the image carrier, and a plurality of the self-light emitting elements, and a plurality of the self-light-emitting elements on a charged surface of the image carrier. The electro-optical device that forms a latent image by irradiating light from an element, the developing device that forms a visible image on the image carrier by attaching toner to the latent image, and the developer from the image carrier. A transfer unit that transfers the image to another object. As described above, since the electro-optical device according to the present invention can be reduced in size, the electro-optical device can be disposed near the image carrier, and the image forming apparatus can also be reduced in size.

An image reading apparatus according to the present invention includes the electro-optical device in which a plurality of the self-light-emitting elements are arranged, and a light-receiving device that converts light emitted from the self-light-emitting elements and reflected by a reading target into an electric signal. . As described above, since the area of the substrate can be reduced in the electro-optical device according to the present invention, the image reading device can also be reduced in size.

Hereinafter, various embodiments according to the present invention will be described with reference to the accompanying drawings. In the drawings, the ratio of dimensions of each part is appropriately changed from the actual one.

FIG. 1 is a cross-sectional view showing an electro-optical device according to an embodiment of the present invention, and FIG. 2 is a partial plan view of the electro-optical device. This electro-optical device is used as a line-type optical head for writing a latent image on an image carrier in an image forming apparatus using an electrophotographic system. As shown in these drawings, the electro-optical device 10 includes a transparent substrate 12 and a plurality of OLED elements (self-emitting elements) 14 formed on the substrate 12. The substrate 12 is preferably a flat plate made of glass, quartz, or plastic, and a large number of OLED elements (self-emitting elements) 14 are arranged on the substrate 12 in a row or other appropriate pattern. In the illustrated form, light emitted from each OLED element 14 passes through the transparent substrate 12 and travels downward in FIG. That is, this electro-optical device is a bottom emission type.

On the substrate 12, connection terminals 18A and 18B for supplying power to the OLED element 14 and wiring 16 for connecting the OLED element 14 and the connection terminals 18A and 18B are formed. The wiring 16 and the connection terminals 18A and 18B are made of a conductive material such as aluminum.

Further, a sealing body 24 is attached to the substrate 12 so as to seal these OLED elements 14 in cooperation with the substrate 12. This sealing isolates the OLED element 14 from the outside air, particularly moisture and oxygen, and suppresses its deterioration. The sealing body 24 can be formed of, for example, glass, metal, ceramic, or plastic. An adhesive 22 is preferably used for attaching the sealing body 24 to the substrate 12. As the adhesive, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used, and an adhesive having a high light shielding property is preferably used.

The types of sealing used in the field of OLED include film sealing in which the entire surface of the sealing body 24 is bonded to the substrate 12 by the adhesive 22 and the peripheral portion of the sealing body 24 by the adhesive 22. There is a cap sealing that provides a space defined by the sealing body 24 and the substrate 12 around the OLED element 14. In the cap sealing, a desiccant is disposed in this space. This embodiment is
Either film sealing or cap sealing may be used. In order to further protect the OLED element 14 from the outside air, one or more passivation layers may be provided in the upper layer of the sealing body 24.

A driver IC, that is, a circuit element 28 for driving the plurality of OLED elements 14 is attached on the sealing body 24. An adhesive 26 is preferably used for attaching the circuit element 28 to the sealing body 24. As the adhesive, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used, and an adhesive having a high light shielding property is preferably used. As will be described later, the circuit element 28 includes a wiring for supplying power to the plurality of OLED elements 14 and an element for switching on / off the energization of these OLED elements 14. The circuit element 28 has connection terminals 30A, 30B, 32A, 32B, and 32C on the upper surface thereof.

Further, a wiring board 27 is attached on the sealing body 24. An adhesive 25 is preferably used for attaching the wiring board 27 to the sealing body 24. As the adhesive, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used, and preferably has a high light shielding property, and the sealing body 24.
The one having a coefficient of thermal expansion between the coefficient of thermal expansion and the coefficient of thermal expansion of the wiring board 27 is used.
An adhesive having a high light shielding property can be obtained, for example, by kneading carbon into the adhesive. Also,
An adhesive with a thermal expansion coefficient between that of glass and that of glass epoxy is
It is obtained by filling the adhesive with glass as a filler.

The wiring board 27 is a multilayer board in which wiring layers for transmitting signals and insulating layers are alternately stacked. The insulating layer is made of, for example, glass epoxy or plastic. In the wiring layer on the upper surface of the wiring board 27, in order to drive the OLED element 14, power lines 20A, 20B,
Elements such as a control circuit and a power supply circuit for controlling 20C, the circuit element 28, and a circuit for converting an external signal are formed. The power supply lines 20A, 20B, and 20C are for supplying power to the circuit element 28 and the OLED element 14, and are made of a conductive material such as copper. The wiring layer on the lower surface of the wiring board 27 is used for grounding. The wiring layer may be used as a copper foil spreading over the entire surface to enhance the heat dissipation effect. In all wiring layers of the wiring board 27, wiring between the above-described elements and the ground is formed. The wiring board 27 is, for example, four layers or six
It may be a layer and may include an unused wiring layer.

The power line 20A is a common low potential power line for the OLED element 14 and the circuit element 28. The power supply line 20 </ b> B is a high potential power supply line for the OLED element 14. The power supply line 20C is a high potential power supply line for the circuit element 28. These power supply lines 20A, 20B, and 20C are connected to a power supply device via a flexible substrate (not shown).

The connection terminals 30A and 30B of the circuit element 28 are made of metal bonding wires 34A and 34, respectively.
B is connected to connection terminals 18A and 18B on the substrate 12 via B, and finally OLED
The element 14 is connected to the cathode and the anode, respectively. Connection terminals 32A, 32B, 32C
Power supply lines 20A, 20B via metal bonding wires 36A, 36B, 36C
, 20C, respectively. Although not shown, the circuit element 28 includes other connection terminals, and is connected to each element on the wiring board 27 via bonding wires.

FIG. 3 is a cross-sectional view showing details of each OLED element 14. The OLED element 14 includes a hole injection layer 46 formed on a transparent anode 42 made of ITO (Indium Tin Oxide), a light emitting layer 48 formed thereon, and a cathode formed thereon. 49. The hole injection layer 46 and the light emitting layer 48 are formed in a recess defined by the insulating layer 40 and the partition wall 44. The material of the insulating layer 40 is, for example, SiO ₂ , and the material of the partition wall 44 is, for example, polyimide.

The anode 42 is connected to the connection terminal 18B via a conductor not shown in FIG. 3, and the cathode 49 is connected to the connection terminal 18A behind the connection terminal 18B, although not shown in detail in FIG. Connected through. These leads are shown schematically as wiring 16 in FIG. The configuration of each OLED element 14 of this embodiment is as described above.
As a variation of the LED element, a type having another layer such as a type in which an electron injection layer is provided between the cathode and the light emitting layer, or a type in which an insulating layer is provided between the anode and the transparent substrate may be used.

FIG. 4 is a block diagram illustrating a drive system of the electro-optical device 10. As shown in FIG. 4, the circuit element 28 described above includes a plurality of, for example, 128 data lines L0 to L127 and a selection circuit 280. In addition to the data signals D0 to D127, the circuit element 28 includes various control signals C.
TL, first power supply potential VIC, and ground potential GND are supplied. Data signal D0-D
127 is applied to data lines L0 to L127 from a data control circuit (not shown). The first power supply potential VIC is supplied from the high potential power supply line 20C for the circuit element 28, and the ground potential GN.
D is given from the common low-potential power line 20A for the OLED element 14 and the circuit element 28.

Each of the pixel blocks B1 to B40 shown in FIG. 4 is a set of a plurality of, for example, 128 pixel circuits P that are driven in one unit time. A clock signal is supplied as a control signal CTL to the selection circuit 280, and the selection circuit 280 selects the selection signal SEL1 according to the clock signal.
... SEL40 is sequentially output. The selection signals SEL1 to SEL40 are input to the pixel blocks B1 to B40, respectively, and are supplied to 128 pixel circuits P in the corresponding pixel block. Each of the selection signals SEL1 to SEL40 becomes active for a period (selection period) of 1/40 of the main scanning period for latent image writing.

The first to forty pixel blocks B1 to B40 are exclusively and sequentially selected by the selection signals SEL1 to SEL40. In this way, the main scanning period is divided into a plurality of selection periods (writing periods),
Since the pixel blocks B1 to B40 are time-division driven, it is not necessary to provide dedicated data lines for each of the 5120 (128 × 40) pixel circuits P, and the number of data lines can be reduced. That is, 5120 pixel circuits P can be controlled by 128 data lines L0 to L127. Each of the first to fourth pixel blocks B1 to B40 includes data lines L0 to L127.
128 pixel circuits P respectively corresponding to. These pixel circuits P are supplied with the second power supply potential VEL and the ground potential GND. The second power supply potential VEL is supplied from the high potential power supply line 20B for the OLED element 14, and the ground potential GND is supplied from the common low potential power supply line 20A for the OLED element 14 and the circuit element 28. Then, the data signals D0 to D127 supplied via the data lines L0 to L127 in each selection period are taken into the pixel circuit P. The data signals D0 to D127 in this example are binary signals for instructing to turn on / off the OLED element.

FIG. 5 is a circuit diagram of each pixel circuit P. Each pixel circuit P includes a holding transistor 281, a driving transistor 282, and the OLED element 14. In the figure, the part built in the circuit element 28 is denoted by reference numeral 28. As is clear from this, the holding transistor 281 and the driving transistor 282 are built in the circuit element 28. Holding transistor 281
One of the selection signals SEL1 to SEL40 is supplied from the selection circuit 280 to the gate of
The source is connected to one of the data lines L0 to L127, whereby the data signal D0
~ D127 is supplied to the source. The drain of the holding transistor 281 and the gate of the driving transistor 282 are connected by a connection line. A stray capacitance is attached to the connection line, and this capacitance acts as a holding capacitance. In the storage capacitor, a binary voltage is written in the selection period, and the written voltage is held until the next selection period. Accordingly, the data signals D0 to D0 are selected in the period in which the holding transistors are selected by the selection signals SEL1 to SEL40.
The OLED element 14 emits light only during a period in which D127 is a signal for instructing lighting of the OLED element 14.

The second power supply potential VEL is supplied to the drain of the drive transistor 282 from the high potential power supply line 20B through the bonding wire 36B and the connection terminal 32B of the circuit element 28.
The source of the driving transistor 282 is connected to the anode of the OLED element 14 through the connection terminal 30B of the circuit element 28, the bonding wire 34B, and the connection terminal 18B on the substrate 12. The drive transistor 282 supplies a drive current corresponding to the voltage (binary value) written in the storage capacitor to the OLED element 14. The cathode of the OLED element 14 includes a low-potential power line 20A to a bonding wire 36A, a connection terminal 32A for the circuit element 28, and a connection terminal 3 for the circuit element 28.
The ground potential GND is supplied through 0A, the bonding wire 34A, and the connection terminal 18B on the substrate 12. The OLED element 14 emits an amount of light corresponding to the magnitude of the drive current.

As described above, the circuit element 28 is instructed to select which pixel block can be energized and whether to energize the OLED element 14 in the selected pixel block (OLED element). The pixel circuit P (more precisely, the holding transistor 281 and the driving transistor 282) for turning on / off the power supply to 14 is incorporated. However, the selection circuit 28
A circuit equivalent to 0 may be provided outside the circuit element 28, or a control circuit that generates the data signals D0 to D127 or various control signals CTL may be provided inside the circuit element 28. Further, it is possible to provide the pixel circuit P on the same substrate as the OLED element 14, and these variations are within the scope of the present invention. The components of these circuit elements 28 may be provided in one element, that is, an IC chip, or may be distributed to a plurality of elements.

Next, a procedure for manufacturing the electro-optical device 10 according to the embodiment will be described. First, as shown in FIG. 6, the OLED element 14, the wiring 16, and the connection terminals 18 </ b> A and 18 </ b> B are formed on the substrate 12.
These forming methods may be any known method, and the description thereof is omitted.

Next, as shown in FIG. 7, a sealing thermosetting or ultraviolet curable adhesive 22 is applied to the substrate 12.
Coat on top. Further, as shown in FIG. 8, the sealing body 24 is placed on the adhesive 22 and the substrate 12 is placed.
Then, the adhesive 22 is cured. As shown in FIG. 8, the sealing adhesive 22 has a protruding portion 22 a that protrudes from the space between the substrate 12 and the sealing body 24 and partially covers the side end of the sealing body 24. Also good. By providing such a protrusion 22a, the sealing effect can be further enhanced. In order to provide the protrusion 22a, the substrate 12 and the sealing body 24 are provided.
The adhesive may be coated on the substrate 12 so that the amount of the adhesive is larger than that which is disposed in the space between the two, and the adhesive may be protruded from the space. It may be coated on the outside.

Next, as shown in FIG. 9, a thermosetting or ultraviolet curable adhesive 2 is applied to the lower surface of the wiring board 27.
On the other hand, a thermosetting or ultraviolet curable adhesive 26 is coated on the lower surface of the circuit element 28. Prior to this, the above-described elements including the power supply lines 20A, 20B, and 20C are formed on the upper surface of the wiring board 27. These forming methods may be any known method, and the description thereof is omitted. Further, the formed power supply lines 20A, 20B, and 20C may be protected with a protective film. Examples of the protective film include a SiO ₂ film, a SiN film, and a combination thereof.

Next, as shown in FIG. 10, the wiring board 27 and the circuit element 28 are attached to the sealing body 24.
Thereafter, the adhesives 25 and 26 are cured. After this curing, the power supply lines 20A, 20B, and 20C may be formed on the upper surface of the wiring board 27. However, it must be before the next work.

Next, as shown in FIG. 11, bonding wire 34A,
34B, 36A, 36B, and 36C are attached. Accordingly, the connection terminals 30A and 30B are connected to the connection terminals 18A and 18B, respectively, and the connection terminals 32A, 32B, and 32C are connected to the power supply lines 20A, 20B, and 20C, respectively. Thereafter, a resin may be piled up and cured so as to cover the circuit element 28. As this resin, those having high light shielding properties are preferable. Thus,
The electro-optical device 10 is completed. Note that the wiring substrate 27 and the circuit element 28 may be attached to the sealing body 24 before the sealing body 24 is attached to the substrate 12.

A power supply line for supplying power to a large number of self-luminous elements and circuits has a large cross-sectional area because a large current needs to flow. When such a power supply line is provided on a substrate on which a self-light emitting element is formed, a substrate having a large area is required. However, according to the arrangement of this embodiment, the power lines 20A, 20B, and 20C overlap the sealing body 24 that seals the OLED element 14, so that OLE
It is possible to reduce the area of the substrate 12 on which the D element 14 is formed. Therefore, substrate 1
2 can be saved, and it contributes to downsizing of the entire apparatus including the electro-optical device 10.

Further, according to the arrangement of this embodiment, the circuit element 28 for driving the OLED element 14 is
Since it is attached to the sealing body 24 that seals the OLED element 14, the area of the substrate 12 on which the OLED element 14 is formed can be further reduced.

Further, according to the arrangement of this embodiment, the connection terminals 30A, 30B, 32 of the circuit element 28 are provided.
A, 32B, 32C and the power supply lines 20A, 20B, 20C are separated from the substrate 12 and the sealing body 24. On the other hand, the connection terminals 30A, 30B, 32A, 32B, 32 of the circuit element 28.
C and the power lines 20A, 20B, and 20C are heated when the bonding wires 36A, 36B, and 36C are attached. The heating is performed, for example, by spot heating with a laser beam. Since the OLED element 14 is vulnerable to heat, the connection terminals 30A, 30B, 32A,
If the heat of the 32B, 32C and the power lines 20A, 20B, 20C is transmitted to the OLED element 14, the OLED element 14 may be damaged or deteriorated. Therefore, when the wire bonding method is adopted in the manufacture of a general electro-optical device, the manufacturing process is limited. However, according to this arrangement, the connection terminals 30A, 30B, 32A, 32B, 32C of the circuit element 28 are provided.
And since the heat of power supply line 20A, 20B, 20C is hard to be transmitted to OLED element 14, the freedom degree of a manufacturing process can be made high.

Since the circuit element 28 is formed using a semiconductor, it may malfunction when exposed to light. The light that the circuit element 28 receives is light emitted from the OLED element 14 and reflected by the substrate 12. According to the embodiment described above, since the light shielding film is formed between the substrate 12 and the circuit element 28 by using the adhesives 22 and 26 having high light shielding properties, a part of the circuit element 28 is covered. The amount of light reaching the element 28 is reduced, and the probability that the circuit element 28 malfunctions can be reduced. Further, in the above-described embodiment, when a resin having a high light-shielding property is deposited and cured so as to cover the circuit element 28, the light-shielding film is formed around the circuit element 28, and thus reaches the circuit element 28. The amount of light is reduced, and the probability that the circuit element 28 malfunctions can be reduced. As is clear from the above, according to the above-described embodiment, the circuit element 28
By covering part or all of this with a light-shielding film, the probability that the circuit element 28 malfunctions can be reduced.

In the illustrated embodiment, the wire bonding method is used as a method for electrically connecting the OLED element 14, the wiring board 27, and the circuit element 28, but other methods may be used. If the other method is a method involving heating of the power supply lines 20A, 20B, and 20C, the effect that the possibility that the OLED element 14 is damaged or deteriorated can be reduced. Further, at least one of the adhesives 22, 25 and 27 may have a high light shielding property. Further, the light shielding film may be formed by forming a metal film having a high light shielding property. The metal film is formed by sputtering, for example.

Further, in the illustrated form, one side end of the sealing body 24 is flush with one side end of the substrate 12, but as a variation of the arrangement of the sealing body and the substrate according to the present invention. The one member may protrude from the other member. In the illustrated form, the power supply lines 20A, 2
0B and 20C are all formed on the wiring board 27, but at least one of the power lines 20A, 20B and 20C is used as a variation of the arrangement of the board, the sealing body and the wiring board according to the present invention. The other may be formed on at least one of the substrate 12 and the sealing body 24. Also in this case, since at least one of the power lines 20A, 20B, and 20C overlaps the sealing body 24, the area of the substrate 12 can be reduced, and the power lines 20A, 20A,
Since at least one of 20B and 20C is formed on the power supply substrate 27, the OLED element 14
The possibility of being destroyed or deteriorated can be reduced.

<Image forming apparatus>
As described above, the electro-optical device 10 can be used as a line-type optical head for writing a latent image on an image carrier in an image forming apparatus using an electrophotographic system. Examples of the image forming apparatus include a printer, a printing part of a copying machine, and a printing part of a facsimile.

FIG. 12 is a longitudinal sectional view showing an example of an image forming apparatus using the electro-optical device 10 as a line type optical head. This image forming apparatus is a tandem type full color image forming apparatus using a belt intermediate transfer body system.

In this image forming apparatus, four organic EL array exposure heads 10K and 10C having the same configuration are used.
, 10M, 10Y are four photosensitive drums (image carriers) 110K, 11 having the same configuration.
Arranged at the exposure positions of 0C, 110M, and 110Y, respectively. The organic EL array exposure heads 10K, 10C, 10M, and 10Y are the electro-optical device 10 described above.

As shown in FIG. 12, this image forming apparatus is provided with a driving roller 121 and a driven roller 122, and an endless intermediate transfer belt 120 is wound around these rollers 121 and 122, as indicated by arrows. Thus, 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, photosensitive drums 110K, 110C, 110M, and 110Y having photosensitive layers on four outer peripheral surfaces are arranged at predetermined intervals. Subscript K
, C, M, and Y mean that they are used to form visible images of black, cyan, magenta, and yellow, respectively. The same applies to other members. Photosensitive drums 110K and 11
0C, 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), organic EL array exposure head 10 (K, C, M, Y), and developing device 114 (K, Y).
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) includes a plurality of OLED elements 1.
4 are arranged so that the arrangement direction of 4 is along the bus (main scanning direction) of the photosensitive drum 110 (K, C, M, Y). The electrostatic latent image is written by irradiating the photosensitive drum with light from the plurality of OLED elements 14. 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.

Black, cyan, magenta, and black formed by such a four-color single color image forming station
The yellow visible images are sequentially primary-transferred onto the intermediate transfer belt 120 to be superimposed on the intermediate transfer belt 120, and as a result, a full-color visible image is obtained. Inside the intermediate transfer belt 120, four primary transfer corotrons (transfer units) 112 (K, C, M, Y) are provided.
Is arranged. The primary transfer corotron 112 (K, C, M, Y) is connected to the photosensitive drum 11.
0 (K, C, M, Y) are arranged in the vicinity of the photosensitive drum 110 (K, C,
The visible image is electrostatically attracted from (M, Y) 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.

The image forming apparatus in FIG. 12 includes an electro-optical device 1 having an organic EL array as writing means.
Since 0 is used, the apparatus can be reduced in size as compared with the case where a laser scanning optical system is used. Further, as described above, since the electro-optical device 10 can be made smaller than the conventional one, the electro-optical device 10 can be disposed at a position close to the photosensitive drums 110K, 110C, 110M, and 110Y, and the image forming apparatus can be further downsized. Is possible.

Next, another embodiment of the image forming apparatus according to the present invention will be described.
FIG. 13 is a longitudinal sectional view of another image forming apparatus using the electro-optical device 10 as a line type optical head. This image forming apparatus is a rotary developing type full-color image forming apparatus using a belt intermediate transfer body system. In the image forming apparatus shown in FIG. 13, a corona charger 168, a rotary developing unit 161, an organic EL array exposure head 167, and an intermediate transfer belt 169 are provided around a photosensitive drum (image carrier) 165. Yes.

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 the electro-optical device 10 described above, and includes a plurality of O
The LED elements 14 are arranged so that the arrangement direction thereof is along the bus (main scanning direction) of the photosensitive drum 165. The electrostatic latent image is written by irradiating the photosensitive drum with light from the plurality of OLED elements 14.

The developing unit 161 includes four developing units 163Y, 163C, 163M, and 163K.
The drums are arranged at an angular interval of ° and can be rotated 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.
Further, the image is transferred to the intermediate 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 9, the 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 forming apparatus is provided with a sheet conveyance path 174 through which a sheet passes. 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). And
The secondary transfer roller 171 moves the intermediate transfer belt 169 when transferring a full-color visible image 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.
75. 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.

The image forming apparatus of FIG. 13 includes an exposure head 16 having an organic EL array as writing means.
7 (electro-optical device 10) is used, the device can be made smaller than when a laser scanning optical system is used. Further, as described above, since the electro-optical device 10 can be made smaller than the conventional one, it can be arranged at a position close to the photosensitive drum 165, and the image forming apparatus can also be made smaller. .

The image forming apparatus to which the electro-optical device 10 can be applied has been described above, but the electro-optical device 10 can be applied to other electrophotographic image forming apparatuses. Within the scope of the invention. For example, the electro-optical device 10 can be applied to an image forming apparatus that directly transfers a visible image from a photosensitive drum to a sheet without using an intermediate transfer belt, and an image forming apparatus that forms a monochrome image. It is.

<Image reading device>
In addition, the electro-optical device 10 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. 14 is a longitudinal sectional view showing an example of an image reading apparatus using the electro-optical device 10 as a line type optical head. A flat platen glass 202 is provided on the upper part of the cabinet 201 of the image reading apparatus, and a document 203 is placed on the platen glass 202 with its image surface facing downward. A platen cover (not shown) presses the document 203 toward the platen glass 202.

Inside the cabinet 201, a high speed carriage 204 and a low speed carriage 205 are arranged so as to be movable in the horizontal direction. The high-speed carriage 204 irradiates the original 203 with the organic E
An L array exposure head 206 and a reflecting mirror 207 are mounted, and two reflecting mirrors 208 and 209 are mounted on the low-speed carriage 205. These organic EL array exposure heads 20
6 and the reflecting mirrors 207, 208, and 209 extend in the direction perpendicular to the paper surface (main scanning direction) in FIG. The organic EL array exposure head 206 is installed so that the arrangement direction of the plurality of OLED elements 14 is along the main scanning direction.

A document reader 210 is disposed at a fixed position inside the cabinet 201. The document reader 210 includes an imaging lens 212 and a line sensor (light receiving device) 213 composed of a large number of photosensitive pixels (charge coupled devices). The line sensor 213 extends in the direction perpendicular to the paper surface (main scanning direction) in FIG. 14, and is arranged so that the arrangement direction of the plurality of photosensitive pixels is along the main scanning direction.

Light emitted from the organic EL array exposure head 206 passes through the platen glass 202 and is reflected by the lower surface of the document 203. Reflected light from the original 203 is transmitted through the platen glass 202, reflected by the reflecting mirrors 207 to 209, and then imaged by the line sensor 213 by the imaging lens 212. The high speed carriage 204 moves in the horizontal direction so that the entire surface of the original 203 is irradiated by the organic EL array exposure head 206, and the low speed carriage 205 is the high speed carriage 204.
The length of the reflected light path from the original 203 to the line sensor 213 is kept constant.

As described above, the electro-optical device 10 is used as the organic EL array exposure head 206 that is an illumination device of an image reading device. However, in this type of lighting device, it is preferable that all of the OLED elements 14 in the range corresponding to the width of the document emit light continuously for a long period of time.
Therefore, in the drive systems of FIGS. 4 and 5, the pixel blocks B1 to B40 are not time-division driven, but the pixel blocks in the range corresponding to the width of the document are continued for at least the length of the document. Therefore, the selection signal may be given simultaneously. Further, the data signals D0 to D1
All 27 may be turned on at the same time. Alternatively, the data lines L0 to L127 and the holding transistor 281 that transmit the data signals D0 to D127 may be eliminated.

The image reading apparatus to which the electro-optical device 10 can be applied has been illustrated above. However, the electro-optical device 10 can be applied to other image reading devices, and such an image forming apparatus is within the scope of the present invention. It is in. For example, the light receiving device may move together with the electro-optical device 10 as an illumination device, or both the light receiving device and the electro-optical device 10 may be fixed and the original or the reading target may be moved and read.

<Other applications>
The electro-optical device according to the present invention can be further applied to various exposure devices, illumination devices, and image display devices.

1 is a cross-sectional view illustrating an electro-optical device according to an embodiment of the invention. FIG. 2 is a partial plan view of the electro-optical device illustrated in FIG. 1. It is sectional drawing which shows the detail of the OLED element in the said electro-optical apparatus. It is a block diagram which shows the drive system of the said electro-optical apparatus. FIG. 5 is a circuit diagram of each pixel circuit in the drive system of FIG. 4. FIG. 3 is a diagram illustrating a first step in a procedure for manufacturing the electro-optical device illustrated in FIG. 1. 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. 10 is a diagram showing a step subsequent to that in FIG. 9. FIG. 11 is a diagram showing a step subsequent to FIG. 10. FIG. 2 is a longitudinal sectional view illustrating an example of an image forming apparatus using the electro-optical device illustrated in FIG. 1. FIG. 4 is a longitudinal sectional view illustrating another example of an image forming apparatus using the electro-optical device illustrated in FIG. 1. FIG. 2 is a longitudinal sectional view illustrating an example of an image reading apparatus using the electro-optical device illustrated in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electro-optical apparatus, 12 ... Board | substrate, 14 ... OLED element (self-light-emitting element), 20A ... Low potential power supply line, 20B ... High potential power supply line, 20C ... High potential power supply line, 22, 25, 26 ... Adhesive (
Light shielding film), 24 ... sealed body, 27 ... wiring substrate, 28 ... circuit element, L0 to L127 ... data line, 280 ... selection circuit, 10K, 10C, 10M, 10Y, 167, 206 ... organic EL array exposure head ( 110K, 110C, 110M, 110Y, 165 ... photosensitive drum (image carrier), 111,168 ... corona charger, 114 ... developer, 112 ... primary transfer corotron (transfer device), 120,169 ... Intermediate transfer belt 161 ... Developing unit 163Y, 163C, 163M, 163K ... Developer 166 ... Primary transfer roller (transfer device), 203 ... Original, 210 ... Original reader, 213 ... Line sensor (light receiving device).

Claims (4)

A substrate on which a first connection terminal is formed;
A plurality of organic light emitting diode elements formed on the first surface of the substrate;
A sealing body disposed on the first surface including at least the organic light emitting diode element and formed of any one of glass, metal, ceramic, and plastic;
A circuit element having a plurality of second connection terminals formed using a semiconductor for driving or controlling the organic light emitting diode element;
A wiring board composed of a multilayer board in which wiring layers and insulating layers are alternately stacked;
A power line for supplying power to at least one of the circuit element and the organic light emitting diode element,
The circuit element is disposed on a third surface opposite to the second surface of the sealing body facing the first surface, and at least one of the plurality of second connection terminals is The first connection terminal is electrically connected with a metal bonding wire and is formed on a fifth surface opposite to the fourth surface of the circuit element facing the third surface,
The wiring board is disposed in a region that does not overlap with a region where the circuit element is disposed on the third surface,
The plurality of second connections that are disposed on the seventh surface opposite to the sixth surface of the wiring board facing the third surface and that are not connected to the first connection terminal. At least one of the terminals is electrically connected to the power supply line by a metal bonding wire.   2. The organic light emitting diode device according to claim 1, wherein a part or all of the circuit element is covered with a light shielding film. An image carrier;
A charger for charging the image carrier;
3. The organic light emitting diode according to claim 1, wherein a plurality of the organic light emitting diode elements are arranged, and a latent image is formed by irradiating light on the charged surface of the image carrier with the plurality of organic light emitting diode elements. Equipment,
A developing unit that forms a visible image on the image carrier by attaching toner to the latent image; and
An image forming apparatus comprising: a transfer unit that transfers the visible image from the image carrier to another object. The organic light emitting diode device according to any one of claims 1 to 3, wherein a plurality of the organic light emitting diode elements are arranged;
An image reading device comprising: a light receiving device that converts light emitted from the organic light emitting diode element and reflected by a reading target into an electric signal.

Images