JP2021082762A - Semiconductor device, exposure device, and image forming apparatus - Google Patents

Abstract

To provide means that prevents disturbance of light emitted by a light emitting element and prevents a reduction in image quality.SOLUTION: A semiconductor device has a light emitting element having a plurality of wiring layers and a light emitting layer. The light emitting element has a first portion in which gate layers of the wiring layers and a cathode layer are laminated on the light emitting layer, and a second portion in which the gate layers are laminated on the light emitting layer and the cathode layer is not laminated. At the second portion, the light emitting layer and the gate layers are covered by a light shielding member.SELECTED DRAWING: Figure 3

Description

The present invention relates to a semiconductor device having a light emitting element, an exposure device, and an image forming device.

In the conventional image forming apparatus, a semiconductor device using a light emitting thyristor as a light emitting element is provided in an exposure apparatus for exposing the image carrier so that an image is formed on the image carrier (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-145662

However, in the conventional technique, there is a problem that the light is disturbed by the reflected light from the electrode connected to the light emitting thyristor as the light emitting element, and the quality of the formed image is deteriorated.
An object of the present invention is to solve such a problem, and to suppress disturbance of light emitted by a light emitting element and to suppress deterioration of image quality.

Therefore, the present invention has a first light emitting element having a plurality of wiring layers and a light emitting layer, and the light emitting element is a first type in which a gate layer and a cathode layer of the wiring layer are laminated on the light emitting layer. It has a portion and a second portion in which the gate layer is laminated on the light emitting layer and the cathode layer is not laminated. In the second portion, the light emitting layer and the gate layer are light-shielding members. It is characterized by being covered with.

As described above, the present invention has the effect of suppressing the disturbance of the light emitted by the light emitting element and suppressing the deterioration of the image quality.

Schematic side sectional view showing the configuration of the printer in the first embodiment. Sectional drawing which shows the structure of the LED head in 1st Example Top view showing the structure of the LED light emitting circuit in the 1st Example Sectional drawing which shows the structure of the LED light emitting circuit in 1st Example Sectional drawing which shows the structure of the LED light emitting circuit in 1st Example Sectional drawing which shows the structure of the LED light emitting circuit in 1st Example Top view showing configuration of LED light emitting circuit in 2nd Example Sectional drawing which shows the structure of the LED light emitting circuit in 2nd Example

Hereinafter, examples of the semiconductor device, the exposure device, and the image forming device according to the present invention will be described with reference to the drawings.

The printer as the image forming apparatus of this embodiment will be described with reference to a schematic diagram showing the configuration of the printer in the first embodiment of FIG.

In FIG. 1, a printer 100 as an image forming apparatus forms an image on a photoconductor drum 41 of an image forming unit based on image data, and a toner made of a resin containing a pigment as a coloring material is used on a printing medium. It forms an image.

The printer 100 is equipped with a paper feed cassette 60 for storing the paper 101 as a print medium, includes a paper feed roller 61 for taking out the paper 101 from the paper feed cassette 60, feeds the paper 101, and an arrow Y in the drawing indicates. Conveying rollers 62, 63 for transporting in the indicated medium transport direction are arranged.
The printer 100 in the present invention is a color electrophotographic system, and in the printer 100, as an image forming unit, a photoconductor drum 41 as an image carrier for forming images of each color of yellow, magenta, cyan, and black, and the photosensitivity thereof. A developer 5 that develops an electrostatic latent image formed on a body drum 41 with toner to form a toner image, and a toner cartridge 51 that supplies toner to the developer 5 are arranged side by side along a transport path of paper 101. It is arranged.

Further, a charging roller 42 that supplies and charges the surface of the photoconductor drum 41 and an LED (Light Emitting Diode) head 3 as an optical head are arranged so as to face the surface of the photoconductor drum 41, and the LED head. Reference numeral 3 denotes the surface of the photoconductor drum 41 charged by the charging roller 42, which is selectively irradiated with light based on the image data to form an electrostatic image.

Further, a transfer roller 80 formed on the photoconductor drum 41 and transferring a toner image, which is an image obtained by visualizing an electrostatic latent image with toner, onto the paper 101 sandwiches a transfer belt 81 that conveys the paper 101 at the transfer unit. The cleaning blade 43, which is arranged so as to face the photoconductor drum 41 and removes the toner remaining on the surface of the photoconductor drum 41 after the paper 101 has passed through the transfer portion, comes into contact with the surface of the photoconductor drum 41. Is arranged.

A fixing device 9 for fixing the toner image formed on the paper 101 by heat and pressure is arranged downstream of the transfer unit, and the transport roller 64 for transporting the paper 101 that has passed through the fixing device 9 and the transport roller 64 thereof. A discharge roller 65 is arranged to discharge the paper 101 to which the paper 101 is conveyed and has an image formed.

Further, a predetermined voltage is applied to the charging roller 42 and the transfer roller 80 by a power source. Then, the transfer belt 81, the photoconductor drum 41, and each roller are rotationally driven by a motor and a gear that transmits the drive, respectively. Further, a power supply and a control device are connected to the developer 5, the LED head 3, the fuser 9, and each motor.

The printer 100 has an external interface for receiving print data from an external device, and forms an image on a print medium based on the print data received by the external interface.

The printer 100 configured in this way includes a control unit that stores a control program in a storage unit such as a memory, and controls the entire printer based on the control program, and a control unit as an arithmetic means.

FIG. 2 is a cross-sectional view showing the configuration of the LED head in the first embodiment, and is a cross-sectional view of the LED head in the longitudinal direction.

In the drawing, the arrow Y indicates the medium transport direction (the lateral direction of the LED head 3), the arrow Z indicates the optical axis direction of the lens array 32 of the LED head 3, and the arrow X indicates the medium transport direction indicated by the arrow Y. And the longitudinal direction of the LED head 3 orthogonal to the direction of the optical axis indicated by the arrow Z is shown. Hereinafter, arrows X, Y, and Z indicate directions similar to those described above.

In FIG. 2, the LED head 3 as an exposure device exposes a photoconductor drum 41 as an image carrier, and includes a base member 30, an LED light emitting circuit 31, a lens array 32, a holder 33, and a clamper. It has 34a and 34b.

The base member 30 is injection-molded using an organic polymer material or the like, and is a member for fixing the substrate 311 of the LED light emitting circuit 31.
The LED light emitting circuit 31 as a semiconductor device includes a substrate 311 and an LED array chip 312.
The substrate 311 is a unit in which the LED array chip 312 is integrated on a predetermined substrate.

The LED array chip 312 is formed by forming an LED array as a light emitting element on a drive circuit.
The lens array 32 is a group of optical lenses in which columnar optical lenses are arranged on the photoconductor drum 41 side with respect to the LED array chip 312, and a large number of columnar optical lenses are arranged along the X direction of the LED array chip 312.

The holder 33 holds the lens array 32 and the LED light emitting circuit 31 in predetermined positions. Openings 33a and 33b into which the clamper 34 is inserted are formed at both ends of the holder 33 and the base member 30 in the Y direction.
As a whole, the holder 33 has a shape like a hollow quadrangular prism formed along the X direction with the side surface on the anti-Z direction side removed, and its cross section is inverted upside down from the capital letter "U". The shape is such that the anti-Z direction side is opened.

The clampers 34a and 34b are inserted through the openings 33a and 33b provided in the base member 30 and the holder 33, respectively, and the springs that integrally sandwich the LED light emitting circuit 31 with the holder 33 via the base member 30. It is a material.
The LED light emitting circuit 31 is restricted from moving in the Z direction by the holder 33 and the clamper 34, and is sandwiched between both ends of the holder 33 in the Y direction to regulate the movement in the Y direction.

At the time of manufacture, the LED head 3 is inserted with the LED light emitting circuit 31 and the base member 30 stacked in the holder 33, and the clampers 34a and 34b are further attached. The clampers 34a and 34b are both made of elastic metal, and the Z-direction surface of the LED light emitting circuit 31 is brought into contact with the support portion of the holder 33 via the base member 30 by the action of the elastic force. Fix it. As a result, the positional relationship between the light emitting element of the LED array chip 312 attached to the LED light emitting circuit 31 and the holder 33 is determined.

In the LED head 3 configured in this way, the LED array chip 312 selectively emits light by the drive circuit, and the light is imaged on the photoconductor drum 41 by the lens array 32. As a result, an image is formed on the photoconductor drum 41.

FIG. 3 is a plan view showing the configuration of the LED light emitting circuit in the first embodiment.
In FIG. 3, the LED light emitting circuit 31 as a semiconductor device has an integrated circuit region 311a, a semiconductor region 311b, a light emitting unit 312a, an anode electrode 313a, a cathode electrode 313k, and a gate electrode 313g on a substrate 311. A contact via 314, a wiring 315, and a pseudo electrode 316 are provided.

The substrate 311 has a plurality of light emitting units 312a arranged in an arrangement direction (X direction) orthogonal to the optical axis direction (Z direction) of the light emitting unit 312a.
The integrated circuit region 311a is formed on the substrate 311 and the semiconductor region 311b is fixed to the integrated circuit region 311a.

On the semiconductor region 311b, a large number of light emitting thyristor chips are formed on the wafer by a well-known semiconductor process.
The light emitting unit 312a forms an LED light emitting element as a light emitting thyristor chip, is arranged in a plurality in the X direction on the semiconductor region 311b, and has terminals of a cathode electrode 313k and a gate electrode 313g. The light emitting unit 312a emits light by passing a gate current from the gate to the cathode and conducting the conduction between the anode and the cathode.

Further, the light emitting unit 312a has a cathode contact portion 312b connected to the cathode electrode 313k and a gate contact portion 312c connected to the gate electrode 313g.

As shown in FIG. 6, the cathode contact portion 312b as the first portion includes an n-type gate layer 321b and a p-type gate layer 321c as the gate layer of the wiring layer on the light emitting layer 321e, and an n-type cathode as the cathode layer. The layer 321d is laminated.

In the gate contact portion 312c as the second portion, as shown in FIG. 6, an n-type gate layer 321b and a p-type gate layer 321c are laminated as a gate layer of the wiring layer on the light emitting layer 321e, and the n-type cathode layer. The 321d is not laminated.

The cathode contact portion 312b and the gate contact portion 312c are arranged so as to be arranged in the medium transport direction (Y direction) when viewed from above in the optical axis direction (Z direction).
In this embodiment, the relationship between the length L1 of the cathode contact portion 312b in the X direction and the length L3 of the gate contact portion 312c in the X direction is L1> L3.

The cathode electrode 313k is a terminal metal arranged above the cathode contact portion 312b of the light emitting portion 312a in the optical axis direction.

The gate electrode 313g is a terminal metal arranged above the gate contact portion 312c of the light emitting portion 312a in the optical axis direction.
The anode electrode 313a is a terminal metal arranged laterally in the X direction of the cathode contact portion 312b and the gate contact portion 312c of the light emitting portion 312a.

Since the anode electrode 313a is common to each light emitting unit 312a, it is not formed in each light emitting unit 312a.

The contact via 314 is a terminal (via hole) connected to the drive circuit.
The wiring 315 connects each terminal of the cathode electrode 313k and the gate electrode 313g with each contact via 314.

The pseudo electrode 316 is a terminal that is not connected to the drive circuit, and is arranged on the side of the cathode contact portion 312b and the gate contact portion 312c of the light emitting unit 312a in the X direction.

With the increase in definition of printed images, miniaturization of the light emitting unit 312a is required, but in order to obtain a sufficient amount of light, it is desirable to increase the size of the light emitting unit 312a as much as possible.
Further, the terminals of the cathode electrode 313k and the gate electrode 313g are formed in the individual light emitting portions 312a, and the light is mainly emitted in the vicinity of the cathode contact portion 312b.

However, since the periphery of the gate contact portion 312c also emits light slightly, if the lens array 32 (see FIG. 2) is formed in the shape of the light emitting portion 312a as it is, the light emitted by the gate contact portion 312c adversely affects the printed image. , The image quality is deteriorated.

Therefore, in order to bring the gate electrode 313g into contact with the gate contact portion 312c and to eliminate the influence of light emission (light leakage) around the gate contact portion 312c, the entire gate contact portion 312c has a light-shielding gate electrode 313g (terminal). By covering with metal), light leakage can be eliminated and the quality of printed images can be improved.

Further, in this embodiment, since the light emitting portion 312a is enlarged, the size relationship between the cathode contact portion 312b and the gate contact portion 312c is the size of the cathode contact portion 312b of the light emitting portion 312a (X of the cathode contact portion 312b). Let L1 be the length in the direction, and L2 be the size of the gate electrode 313g (terminal metal) of the gate contact portion 312c (the length of the gate electrode 313g (terminal metal) of the gate contact portion 312c in the X direction). It is L2. That is, the length L2 of the gate electrode 313g (terminal metal) in the X direction is shorter than the length L1 of the cathode contact portion 312b of the light emitting portion 312a in the X direction.

FIG. 4 is a cross-sectional view showing the configuration of the LED light emitting circuit in the first embodiment, and is a cross-sectional view taken along the line AA'of the cathode contact portion 312b of the LED light emitting circuit 31 in FIG.
Further, FIG. 6 is a cross-sectional view showing the configuration of the LED light emitting circuit in the first embodiment, and is a CC'cross-sectional view of the LED light emitting circuit 31 in FIG.

In FIGS. 4 and 6, the p-type anode layer 321a, the light emitting layer 321e, the n-type gate layer 321b, the p-type gate layer 321c, and the p-type gate layer 321c are placed on the flattening film 320 of the semiconductor region 311b (see FIG. 3) of the substrate 311. The n-type cathode layers 321d are laminated in this order in the optical axis direction (Z direction).

The p-type anode layer 321a is arranged on the substrate 311 side of the light emitting layer 321e in the optical axis direction (Z direction), and each light emitting layer 321e is arranged so as to be connected to one common p-type anode layer 321a. There is.
Further, a cathode electrode 313k is arranged on the upper surface of the n-type cathode layer 321d.
Further, the side surfaces of the p-type anode layer 321a, the light emitting layer 321e, the n-type gate layer 321b, the p-type gate layer 321c, and the n-type cathode layer 321d, and the upper surface of the n-type cathode layer 321d except for the cathode electrode 313k are insulating layers. It is coated with 317.

The light emitting portion 312a is formed by the p-type anode layer 321a, the light emitting layer 321e, the n-type gate layer 321b, the p-type gate layer 321c, and the n-type cathode layer 321d.
That is, the light emitting unit 312a as a light emitting element has a p-type anode layer 321a, an n-type gate layer 321b, a p-type gate layer 321c, an n-type cathode layer 321d, and a light emitting layer 321e as a plurality of wiring layers. ing.

The anode electrode 313a is formed of a light reflecting member and is connected to the p-type anode layer 321a of the wiring layer.
The pseudo electrode 316 is formed of a light reflecting member and is arranged so as to come into contact with the p-type anode layer 321a via an insulating layer, but is not connected to the p-type anode layer 321a.

The length L1 of the cathode contact portion 312b of the light emitting portion 312a (the length of the cathode contact portion 312b in the X direction) is the length of the base portion in which the p-type anode layer 321a protrudes in the Z direction in the X direction.

FIG. 5 is a cross-sectional view showing the configuration of the LED light emitting circuit in the first embodiment, and is a BB'cross-sectional view of the gate contact portion 312c of the LED light emitting circuit 31 in FIG.
In FIGS. 5 and 6, a p-type anode layer 321a, a light emitting layer 321e, an n-type gate layer 321b, and a p-type gate layer 321c are formed on the flattening film 320 of the semiconductor region 311b (see FIG. 3) of the substrate 311. , Are stacked in this order.

Further, a gate electrode 313g is arranged on the upper surface of the p-type gate layer 321c.

Therefore, in the gate contact portion 312c, the upper part of the light emitting layer 321e, the n-type gate layer 321b, and the p-type gate layer 321c is covered with the gate electrode 313g (terminal metal) as a light-shielding member.

Further, the upper surface of the p-type gate layer 321c is coated with the insulating layer 317 except for the side surfaces of the p-type anode layer 321a, the light emitting layer 321e, the n-type gate layer 321b, and the p-type gate layer 321c, and the gate electrode 313g. ..

The length of the gate electrode 313g (terminal metal) of the gate contact portion 312c (the length of the gate electrode 313g (terminal metal) of the gate contact portion 312c in the X direction) L2 is the length of the gate electrode 313g in the X direction. is there. Further, the length L3 of the gate contact portion 312c in the X direction is the length of the light emitting layer 321e in the X direction.

C or Zn is doped as an impurity of the p-type (p-type anode layer 321a and p-type gate layer 321c) described above, and Si is doped as an impurity of the n-type (n-type gate layer 321b and n-type cathode layer 321d).

The anode layer (p-type anode layer 321a), both gate layers (n-type gate layer 321b and p-type gate layer 321c), and the cathode layer (n-type cathode layer 321d) are made of AlGaAs. The anode layer and the cathode layer have a higher Al composition ratio than the gate layer, and in this case, as the Al composition ratio increases, the band gap also increases.
The etching stop layer between the p-type anode layer 321a and the light emitting layer 321e and between the p-type gate layer 321c and the n-type cathode layer 321d is formed of InGaP.

For example, etching is performed halfway between the n-type cathode layer 321d and the p-type gate layer 321c with a mixed solution of phosphoric acid, hydrogen peroxide solution, and water.

InGaP has an etching rate of about 1/100 that of AlGaAs in this mixed solution, so that etching can be stopped by the etching stop layer. Therefore, the InGaP layer may be about 10 to 50 nm.
After the etching is stopped on the InGaP surface, the etching stop layer is removed with hydrochloric acid, for example, to form a gate electrode.

Next, the p-type anode layer 321a is etched with the above mixed solution to form the cathode electrode 313k on the upper surfaces of the anode electrode 313a, the pseudo electrode 316, and the n-type cathode layer 321d, thereby forming the light emitting element of the light emitting thyristor. To form.

Then, the p-type anode layer 321a, the light emitting layer 321e, the n-type gate layer 321b, the p-type gate layer 321c, and the n-type cathode layer 321d are coated with an insulating film 317 such as polyimide. The insulating film 317 transmits light.

As shown in FIGS. 3, 4 and 5, anode electrodes 313a and pseudo electrodes 316 are alternately arranged between the light emitting portions 312a adjacent to each other in the X direction.
Further, as shown in FIGS. 4 and 5, the cross section of the pseudo electrode 316 is the same as the cross section of the terminal metal of the anode electrode 313a (for example, a terminal metal formed of gold, an alloy of gold, aluminum, etc.). Yes, it is also formed on the insulating film 317.

The anode electrodes 313a are arranged on one side of each light emitting portion 312a in the X direction so as to face the light emitting layer 321e. In this embodiment, the anode electrode 313a is arranged on one side of the cathode contact portion 312b and the gate contact portion 312c.
Further, the anode electrode 313a is formed from the p-type anode layer 321a to a position closer to the light emitting surface 312d than the light emitting layer 321e with respect to the substrate 311 in the Z direction.

Further, the anode electrode 313a has an angle θ formed by the facing surface 313b facing the light emitting layer 321e and the surface (X direction) of the p-type anode layer 321a of less than 90 degrees (more preferably in the range of 30 to 60 degrees). It is formed to be.

The pseudo electrode 316 is arranged in the X direction on the other side of each light emitting portion 312a where the anode electrode 313a is not arranged, facing the light emitting layer 321e. In this embodiment, the pseudo electrode 316 is arranged on the other side of the cathode contact portion 312b and the gate contact portion 312c.

Further, the pseudo electrode 316 is formed from the p-type anode layer 321a to a position closer to the light emitting surface 312d than the light emitting layer 321e with respect to the substrate 311 in the Z direction.
Further, the pseudo electrode 316 has an angle θ formed by the facing surface 316b facing the light emitting layer 321e and the surface (X direction) of the p-type anode layer 321a of less than 90 degrees (more preferably in the range of 30 to 60 degrees). It is formed to be.

The operation of the above-described configuration will be described.

First, the operation of the printer will be described with reference to FIG.

The surface of the photoconductor drum 41 of the printer 100 is charged by the charging roller 42 to which a voltage is applied by the power supply device. Subsequently, when the surface of the photoconductor drum 41 charged by the rotation of the photoconductor drum 41 reaches the vicinity of the LED head 3, it is exposed by the LED head 3 and an electrostatic latent image is formed on the surface of the photoconductor drum 41. .. This electrostatic latent image is developed by the developer 5, and a toner image is formed on the surface of the photoconductor drum 41.

On the other hand, the paper 101 set in the paper feed cassette 60 is taken out from the paper feed cassette 60 by the paper feed roller 61, and is conveyed to the vicinity of the transfer roller 80 and the transfer belt 81 by the transfer rollers 62 and 63.

When the toner image on the surface of the photoconductor drum 41 obtained by development reaches the vicinity of the transfer roller 80 and the transfer belt 81 due to the rotation of the photoconductor drum 41, a voltage is applied to the transfer roller 80 and the power supply device. The transfer belt 81 transfers the toner image on the surface of the photoconductor drum 41 onto the paper 101.

Subsequently, the paper 101 on which the toner image is formed on the surface is conveyed to the fixing device 9 by the rotation of the transfer belt 81, and the toner image on the paper 101 is melted by being heated while being pressurized by the fixing device 9. Then, it is fixed on the paper 101. The paper 101 on which the toner image is fixed is discharged to the discharge unit 7 by the transport roller 64 and the discharge roller 65, and the operation of the printer 100 ends.

Next, the operation of the LED light emitting circuit 31 of the LED head 3 shown in FIG. 2 will be described with reference to FIGS. 3, 4, and 5.

As shown in FIG. 4, in the light emitting unit 312a of the LED light emitting circuit 31, the light emitted by the light emitting layer 321e near the cathode electrode 313k, the n-type gate layer 321b, the p-type gate layer 321c, the n-type cathode layer 321d, The light RZk that passes through the cathode contact portion 312b and travels in the Z direction is emitted from the light emitting surface 312d of the cathode contact portion 312b and becomes light that exposes the surface of the photoconductor drum 41 shown in FIG.

Further, the light RXk1 emitted by the light emitting layer 321e that passes through the insulating film 317 and travels in the anti-X direction on the anode electrode 313a side is reflected by the facing surface 313b of the anode electrode 313a and reflected in the direction of the substrate 311. It becomes the light RXk1'that advances.

Further, the light RXk2 emitted by the light emitting layer 321e, which passes through the insulating film 317 and travels in the X direction on the pseudo electrode 316 side, is reflected by the facing surface 316b of the pseudo electrode 316 and reflected in the direction of the substrate 311. It becomes the light RXk2'advancing.

On the other hand, as shown in FIG. 5, in the light emitting unit 312a of the LED light emitting circuit 31, the light emitted by the light emitting layer 321e near the gate electrode 313g is transmitted through the n-type gate layer 321b and the p-type gate layer 321c, and Z. The light RZg traveling in the direction is reflected by the gate electrode 313g and is confined in the light emitting unit 312a.

Further, the light RXg1 emitted by the light emitting layer 321e that passes through the insulating film 317 and travels in the anti-X direction on the anode electrode 313a side is reflected by the facing surface 313b of the anode electrode 313a and reflected in the direction of the substrate 311. It becomes the light RXg1'that advances.

Further, the light RXg2 emitted by the light emitting layer 321e that passes through the insulating film 317 and travels in the X direction on the pseudo electrode 316 side is reflected by the facing surface 316b of the pseudo electrode 316 and reflected in the direction of the substrate 311. It becomes the light RXg2'advancing.

In this way, the anode electrode 313a and the pseudo electrode 316 are formed closer to the n-type cathode layer 321d than the light emitting layer 321e to a higher position, and the facing surface 313b of the anode electrode 313a and the facing surface 316b of the pseudo electrode 316 and the light emitting layer. By setting the angle θ formed by the arrangement direction (X direction) of the 321e to less than 90 degrees, the light emitted from the light emitting layer 321e can be confined in the light emitting unit 312a.

When only the anode electrode 313a is arranged next to one of the light emitting units 312a in the X direction (arrangement direction) in which the plurality of light emitting units 312a are arranged, the light emitted from the light emitting unit 312a is reflected by the anode electrode 313a. However, the amount of light was non-uniform on the left and right in the X direction with reference to the light emitting unit 312a.

In this embodiment, in the X direction (arrangement direction) in which a plurality of light emitting units 312a are arranged, the anode electrode 313a is arranged next to (one side) the light emitting unit 312a, and the anode electrode 313a sandwiches the light emitting unit 312a. By arranging the pseudo electrode 316 which is not connected to the drive circuit on the opposite side (other side) of the above, the amount of light emitted from the light emitting unit 312a can be made uniform on the left and right sides in the X direction with reference to the light emitting unit 312a. ..

Therefore, it is possible to suppress the disturbance of the light emitted by the light emitting unit 312a and suppress the deterioration of the image quality.

Further, regarding light emission from the vicinity of the gate electrode 313g, the light leaking from the vicinity of the gate electrode 313g can be reduced by covering the contact terminal with the gate electrode 313g.

As described above, in the first embodiment, it is possible to obtain the effect of suppressing the disturbance of the light emitted by the light emitting element and suppressing the deterioration of the image quality.

The configuration of the second embodiment is such that the length L2 of the gate electrode 313 g (terminal metal) in the X direction is longer than the length L1 of the light emitting unit 312a shown in FIG. 3 in the X direction. The configuration of the second embodiment is shown in a plan view showing the configuration of the LED light emitting circuit in the second embodiment of FIG. 7 and a cross-sectional view showing the configuration of the LED light emitting circuit in the second embodiment of FIG. explain. FIG. 8 is a DD'cross-sectional view of the LED light emitting circuit 31 in FIG. 7.

The same parts as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 7, in the second embodiment, the relationship between the length L1 of the cathode contact portion 312b in the X direction and the length L3 of the gate contact portion 312c in the X direction is L1 = L3. ..

In this case, the length L2 of the gate electrode 313g (terminal metal) in the X direction is made longer than the length L1 of the cathode contact portion 312b in the X direction of the light emitting portion 312a.
In this way, the pseudo electrode 316 can be used even when L1 <L2.

However, since the area of the pseudo electrode 316 must be reduced due to the distance of the gate electrode 313g of the adjacent light emitting portion 312a, the pseudo electrode 316 is arranged on the side of the gate contact portion 312c of the adjacent light emitting portion 312a. Instead, it is arranged on the side of the cathode contact portion 312b. The pseudo electrode 316 is arranged on the other side of the cathode contact portion 312b as in the first embodiment.

Further, as shown in FIG. 8, for light emission in the vicinity of the gate electrode 313 g, by covering the gate contact portion 312c with the gate electrode 313 g (terminal metal), the light leaking from the upper surface and the side can be reduced.

The operation of the above-described configuration will be described.

The operation of the LED light emitting circuit will be described with reference to FIGS. 7 and 8.

As shown in FIG. 8, in the light emitting unit 312a of the LED light emitting circuit 31, the light RZg emitted by the light emitting layer 321e near the gate electrode 313g and traveling in the Z direction is confined by the gate electrode 313g (terminal metal). ..

Further, the light RXg1 emitted by the light emitting layer 321e near the gate electrode 313g, which passes through the insulating film 317 and travels in the anti-X direction on the anode electrode 313a side, is reflected by the gate electrode 313g (terminal metal) and is reflected on the substrate. The light RXg1'reflects in the direction of 311 and travels.

Further, the light RXg2 emitted by the light emitting layer 321e near the gate electrode 313g, which passes through the insulating film 317 and travels in the X direction on the pseudo electrode 316 side, is reflected by the gate electrode 313g (terminal metal) and is reflected on the substrate 311. The light RXg2'reflects in the direction of.

By covering the gate contact portion 312c with the gate electrode 313g (terminal metal) in this way, the light emitted from the light emitting layer 321e can be confined in the light emitting portion 312a.
The light emitted by the light emitting layer 321e near the cathode electrode 313k proceeds in the same manner as in the first embodiment.

As described above, in the second embodiment, the length L2 of the gate electrode 313g (terminal metal) in the X direction is longer than the length L1 of the cathode contact portion 312b in the X direction of the light emitting portion 312a. Further, for light emission in the vicinity of the gate electrode 313 g, the same effect as in the first embodiment can be obtained by covering the gate contact portion 312c with the gate electrode 313 g (terminal metal).

In the first embodiment and the second embodiment, the p-gate light emitting thyristor having a pnpn structure is used, but the present invention is not limited to this, and an n gate light emitting thyristor may be used. Further, an n-gate light emitting thyristor having an npnp structure or a p-gate light emitting thyristor may be used.
Further, although the image forming apparatus has been described as a printer, it may be a copying machine, a facsimile machine, a multifunction device (MFP), or the like.

3 LED head 5 Developer 7 Discharger 9 Fixer 30 Base member 31 LED light emitting circuit 32 Lens array 33 Holder 34a, 34b Clamper 41 Photoreceptor drum 42 Charging roller 43 Cleaning blade 51 Toner cartridge 60 Feed cassette 61 Feed roller 62 , 63, 64 Conveyor roller 65 Discharge roller 100 Printer 311 Board 311a Integrated circuit area 311b Semiconductor area 312 LED array chip 313a Anode electrode 313k Cathode electrode 313g Gate electrode 314 Contact via 315 Wiring 316 Pseudo electrode 321a p type anode layer 321e n-type gate layer 321cp p-type gate layer 321d n-type cathode layer

Claims (10)

It has a light emitting element having a plurality of wiring layers and a light emitting layer,
The light emitting element is
A first portion in which the gate layer and the cathode layer of the wiring layer are laminated on the light emitting layer, and
It has a second portion in which the gate layer is laminated on the light emitting layer and the cathode layer is not laminated.
A semiconductor device characterized in that, in the second portion, the light emitting layer and the gate layer are covered with a light-shielding member. In the semiconductor device according to claim 1,
further,
A substrate in which a plurality of the light emitting elements are arranged in a direction orthogonal to the optical axis direction of the light emitting element, and
An anode electrode formed of a light reflecting member and connected to the anode layer of the wiring layer,
Pseudo-electrodes made of light-reflecting members and
Have,
The anode electrodes are arranged on one side of each of the light emitting elements in the arrangement direction of the light emitting elements so as to face the light emitting layer.
A semiconductor device characterized in that the pseudo electrode is arranged on the other side of each of the light emitting elements in which the anode electrode is not arranged in the arrangement direction of the light emitting element so as to face the light emitting layer. In the semiconductor device according to claim 2,
The anode layer is arranged on the substrate side of the light emitting layer in the optical axis direction.
The light emitting layer of each of the light emitting elements is arranged so as to be connected to one common anode layer.
The anode electrode and the pseudo electrode
It is formed from the anode layer to the substrate at a position closer to the light emitting surface than the light emitting layer in the optical axis direction.
Further, the semiconductor device is characterized in that the angle formed by the arrangement direction of the light emitting elements and the facing surface facing the light emitting layer is less than 90 degrees. In the semiconductor device according to claim 2 or 3.
A semiconductor device characterized in that the length of the light-shielding member in the arrangement direction is shorter than the length of the first portion in the arrangement direction. In the semiconductor device according to claim 4,
The anode electrodes are arranged on one side of the first portion and the second portion in the arrangement direction of the light emitting element.
A semiconductor device characterized in that the pseudo electrode is arranged on the other side of the first portion and the second portion where the anode electrode is not arranged in the arrangement direction of the light emitting element. In the semiconductor device according to claim 2 or 3.
A semiconductor device characterized in that the length of the light-shielding member in the arrangement direction is longer than the length of the first portion in the arrangement direction. In the semiconductor device according to claim 6,
The anode electrode is arranged on one side of the first portion in the arrangement direction of the light emitting element.
A semiconductor device characterized in that the pseudo electrode is arranged on the other side of the first portion where the anode electrode is not arranged in the arrangement direction of the light emitting element. In the semiconductor device according to any one of claims 1 to 6.
The light-shielding member is a semiconductor device characterized by being a gate electrode. An exposure apparatus that exposes an image carrier.
An exposure apparatus comprising the semiconductor device according to any one of claims 1 to 8. An image forming apparatus that forms an image on an image carrier.
An image forming apparatus comprising the exposure apparatus according to claim 9.

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