JP2000091644A - Light emitting diode element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting diode element the light emitting pattern of which can be improved in uniformity and, at the same time, can utilize zinc diffusion in its manufacturing process. SOLUTION: In an LED array for LED printing head, Zn diffusing areas 12 are arranged on the surface of a GaAsP substrate 10 in an array form and LEDs which use the p-n junctions between the substrate 10 and areas 12 as light emitting sections are formed. On the Zn diffusing areas 12, scattering bodies 14 composed of truncated cone-like opal plates in which many light reflecting particles are scattered are formed. The light rays emitted from the p-n junctions between the substrate 10 and areas 12 are condensed upon a photosensitive drum and form very small dot images on the photosensitive surface of the drum through an unmagnified image forming optical system after the uneven light quantity of a nonuniform luminous pattern is corrected to a uniform light quantity by means of the scattering bodies 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode element, and more particularly to a light emitting diode element used for an optical printer or a copier head.
It relates to an ED (Light Emitting Diode) array.

[0002]

2. Description of the Related Art An optical printer using an LED array as a head has been widely used since it has a merit that it is more resistant to deformation of an optical system due to vibration and heat than an optical printer of a laser raster system. . This conventional LED
An optical printer using an array will be described with reference to FIG. Here, FIG. 10 is a schematic sectional view including a photosensitive drum and an optical system of a writing system of the optical printer. As shown in FIG. 10, LEDs in which LEDs are arranged in an array
The light 42 emitted from the light source 40 is incident on the same-magnification imaging optical system 44, and the light 46 passing through the same-magnification imaging optical system 44 is condensed on a photosensitive drum 48 to expose the photosensitive surface. It has become.

As an LED light source used in such an optical printer, there has been reported an LED array in which a compound semiconductor layer is grown on an inexpensive semiconductor substrate and which has a light emitting portion projecting from the semiconductor substrate (Japanese Patent Application Laid-Open No. HEI 9-208572). 9-449
No. 55). Hereinafter, this LED array is shown in FIG.
This will be described with reference to FIG. Here, FIG.
FIG. 12 is a plan view showing the array, and FIG. 12 is a sectional view taken along line AA.

For example, a first semiconductor layer 52 of n-type GaAs is formed on a semiconductor substrate 50 of p-type Si or GaAs, and an n-type A
a second semiconductor layer 54 of lGaAs and p-type AlGa
A third semiconductor layer 56 made of As is laminated in order. A semiconductor junction is formed at the interface between the second semiconductor layer 54 and the third semiconductor layer 56.
That is, the light emitting region layer is formed by the second semiconductor layer 54 and the third semiconductor layer 56.

The first, second, and third semiconductor layers 52, 54, and 56 are formed in an island shape, and are covered with a protective film 58 made of, for example, a silicon nitride film. Further, the first semiconductor layers 52 are alternately connected to alternately different common electrodes 60a and 60b. Also,
An individual electrode 62 for connecting to an external circuit is connected to the third semiconductor layer 56.

Thus, by selecting a combination of the common electrodes 60a and 60b and the individual electrodes 62, each L
The ED is selected to emit light. And
The light emitted from the LED is extracted in a direction perpendicular to the plane of the paper of FIG. 11 and is not illustrated here, but is imaged on the photosensitive drum by an equal-magnification imaging optical system such as a condensing lens as shown in FIG. Is done.

However, in the LED array according to the above-mentioned Japanese Patent Application Laid-Open No. 9-45555, non-uniformity of current injection into the light emitting region layer occurs depending on the electrode shape of the individual electrode 62. There is a problem that the property causes unevenness of the proximity pattern of the light emitting pattern. That is, the individual electrode 62 is formed at the center of the light emitting region layer formed by the stacked second semiconductor layer 54 and the third semiconductor layer 56 and emits the strongest light in the periphery thereof. When the light is emitted in the form of an image and an image is formed by an equal-magnification image forming optical system, the image forming pattern deviates from a circle, which is not desirable as an LED array for an LED head.

Note that the LE shown in FIGS.
In addition to the D array, an LED head using an LED array using zinc diffusion is also being sold. In this case as well, besides the unevenness of current injection into the light emitting region layer depending on the electrode shape, a diffusion front is also required. The proximity image unevenness of the light emitting pattern depending on the unevenness and the unevenness of the concentration of zinc occurs, and the same problem is caused.

On the other hand, there has been reported an example of an LED in which a structure is devised so as to make current injection uniform (see Japanese Patent Application Laid-Open No. Hei 4-229665). Hereinafter, this LED will be described with reference to FIG. Here, FIG. 13 is a schematic sectional view showing an LED.

For example, an n-InGaAlP cladding layer 72 and an InGaAl
P active layer 74 and p-InGaAlP cladding layer 76
Are sequentially stacked to form a double heterostructure portion (light emitting region layer). Also, on this double heterostructure part,
An n-InGaAlP current blocking layer 80 of the size of a light extraction side electrode is interposed via a p-InGaP cap layer 78.
Are formed. On the p-InGaP cap layer 78 and the n-InGaAlP current blocking layer 80, a p-GaAlAs current diffusion layer 82 having a larger band gap than the n-InGaAlP active layer 74 is formed.

The p-GaAlAs current diffusion layer 8
2, a p-GaAs contact layer 84 having a shape corresponding to the n-InGaAlP current blocking layer 80 is formed.
Au-Zn is formed on the p-GaAs contact layer 84.
A p-side electrode 86 is formed as a light extraction side electrode. On the other main surface of the n-GaAs substrate 70, an n-side electrode 88 made of Au-Ge is formed.

Thus, the p-GaAlAs current diffusion layer 82 is formed between the p-side electrode 86 and the light-emitting region layer, and further between the p-GaAlAs current diffusion layer 82 and the light-emitting region layer immediately below the p-side electrode 86. Since the n-InGaAlP current blocking layer 80 is formed, the current injected from the p-side electrode 86 spreads in the p-GaAlAs current diffusion layer 82 without concentrating immediately below the p-side electrode 86,
Further, due to the presence of the n-InGaAlP current blocking layer 80, it is diffused to its peripheral portion and injected into the light emitting region layer.
For this reason, uniform light emission over a wide area is possible.

[0013]

However, in the above-mentioned LED disclosed in Japanese Patent Application Laid-Open No. Hei 4-229665, the uniformity of light emission is ensured to a certain extent by making the current injection into the light emitting region layer uniform over a wide area. Although it is possible to make the light emission pattern uniform, since epitaxial growth is necessary in the manufacturing process,
There is a problem that it cannot be used in an LED array using Zn diffusion.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting diode element which can improve the uniformity of a light emitting pattern and can utilize Zn diffusion in its manufacturing process. With the goal.

[0015]

The above object is achieved by the following light emitting diode device according to the present invention. That is,
The light emitting diode element according to claim 1 is characterized in that a scatterer that scatters light emitted from the light emitting unit is provided on the light emitting unit of the light emitting diode.

As described above, in the light emitting diode device according to the first aspect, since the scatterer for scattering the light radiated from the light emitting unit is provided on the light emitting unit, the light emitting pattern is not uniform from the light emitting unit. Since the light emitted by the light-emitting diode element is scattered in the process of passing through the scatterer, the radiation pattern of the light-emitting diode element is made uniform. Therefore, when the light-emitting diode elements are arranged in an array and used in a print head of an optical printer, variations and anisotropy in the beam shape on the photosensitive surface of the print head are suppressed, and a higher quality image is formed. .

According to a second aspect of the present invention, there is provided the light emitting diode element according to the first aspect,
The scatterer has a substantially conical or truncated cone shape.

As described above, in the light emitting diode element according to the second aspect, since the scatterer that scatters the light emitted from the light emitting unit has a substantially conical or truncated cone shape, the radiated light from the light emitting unit is obtained. When the light passes through the scatterer and is scattered to the outside, the conical side surface or the truncated conical upper surface and the side surface of the scatterer can be regarded as a new light source, so that the direction perpendicular to the substrate of the light emitting diode element, that is, The light emitted in the vertical direction of the substrate is the sum of the contributions of light emission from the top and side surfaces of the conical side surface or the truncated cone shape. For this reason, the ratio of the emitted light in the direction perpendicular to the substrate increases as compared with the case of the planar structure, and the emission intensity increases. Therefore, when the light emitting diode elements are arranged in an array and used for a print head of an optical printer, the amount of light transmitted to the photosensitive surface via the same-magnification image forming optical system increases, that is, the light amount of the beam on the image surface decreases. As a result, the writing time of the print head is reduced, and higher-speed printing is realized.

According to a third aspect of the present invention, there is provided a light emitting diode element according to the first aspect,
The scatterer is made of glass in which particles are dispersed.

As described above, in the light-emitting diode device according to the third aspect, by using glass in which particles are dispersed, for example, opal glass, as the scatterer, a large number of particles dispersed in the glass are used. As a result, the light emitted from the light emitting unit is scattered, so that even if the light is emitted in a non-uniform light emission pattern, the radiation pattern can be easily made uniform. In this case,
Since many particles dispersed in the glass work as a new light source, the longer the light from the light-emitting part passes through the opal glass, the more effective it is to make the uneven light emission pattern uniform. Is done.

According to a fourth aspect of the present invention, there is provided the light emitting diode element according to the first aspect, wherein
An optical system for condensing light scattered by the scatterer in a predetermined direction is provided.

As described above, in the light emitting diode element according to the fourth aspect, the optical system for condensing the light scattered by the scatterer in a predetermined direction is provided.
Of the radiated light that has been made uniform in the scatterer, it is possible to effectively use light that is wasted other than in a predetermined direction, for example, a direction perpendicular to the substrate of the light emitting diode element. Therefore,
When these light-emitting diode elements are arranged in an array and used in a print head of an optical printer, if this optical system is not provided, light that deviates from the visual field power of the unity-magnification image forming optical system is also combined and scattered. Since the emitted light can be used efficiently, the amount of beam on the image plane increases, the writing time of the print head is reduced, and higher-speed printing is realized.

According to a fifth aspect of the present invention, there is provided the light emitting diode element according to the fourth aspect, wherein
The optical system for condensing the light scattered by the scatterer in a predetermined direction is a reflection mirror provided around the scatterer.

As described above, in the light emitting diode device according to the fifth aspect, since the reflecting mirror is provided around the scatterer, a predetermined direction, for example, light emission, of the radiated light uniformed in the scatterer is provided. Since it is possible to bend and condense light emitted in a direction other than the substrate vertical direction of the diode element in the direction perpendicular to the substrate, most of the uniform light emitted from the scatterer is effectively used without waste. . Therefore, the function of the light emitting diode device according to the fourth aspect is easily achieved.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described. (First Embodiment) FIG. 1 is a schematic sectional view showing an LED array for an LED print head according to a first embodiment of the present invention, and FIGS. FIG. 7 is a process cross-sectional view for describing the method for manufacturing the LED array for the head.

An LED array for an LED print head according to this embodiment corresponds to the first, second, and third aspects, and has a truncated cone-shaped scatterer incorporated in each LED of the LED array. . That is, as shown in FIG. 1, the LED for the LED print head according to the present embodiment
In the array, the surface of the GaAsP substrate 10 has a diameter of 10 mm.
The μm Zn diffusion regions 12 are formed in an array. Then, an LED having a pn junction between the GaAsP substrate 10 and the Zn diffusion region 12 as a light emitting portion is formed. The pitch of the Zn diffusion region 12 is 60
It is 42.5 μm corresponding to 0 dpi. The present embodiment is characterized in that a scatterer 14 made of a 7 μm-thick truncated cone-shaped opal plate is formed on these Zn diffusion regions 12. A large number of light-reflecting particles are dispersed inside the scatterer 14 made of the opal plate.

Although not shown, the GaAsP substrate 1
In the vertical direction of 0, a 1: 1 imaging optical system and a photosensitive drum are provided. Then, the GaAsP substrate 10 and Zn
Light emitted from a pn junction (light emitting portion) with the diffusion region 12 is condensed on a photosensitive drum via an equal-magnification imaging optical system, and a minute point image is formed on the photosensitive surface. ing.

Next, L for the LED print head shown in FIG.
A method of manufacturing the ED array will be described with reference to FIGS. First, Zn diffusion regions 12 having a diameter of 10 μm are formed in an array on the surface of a GaAsP substrate 10. Thus, an LED comprising a pn junction between the GaAsP substrate 10 and the Zn diffusion region 12 is formed. The pitch of the Zn diffusion region 12 is 42.5 μm corresponding to 600 dpi.
m (see FIG. 2).

Next, a 7 μm-thick opal plate 14a in which a large number of light-reflecting particles are dispersed is bonded to the GaAsP substrate 10 using a transparent adhesive (see FIG. 3).

Next, after a photoresist is applied to a thickness of 2 μm on the opal plate 14a, it is patterned by the photolithography technique in accordance with the Zn diffusion region 12. Thus, a truncated cone-shaped photoresist 16 serving as an etching mask is formed (see FIG. 4).

Finally, under the etching conditions in which the etching rate of the opal plate 14a with respect to the photoresist 16 is tripled, the opal plate 14a is selectively etched using the photoresist 16 as a mask, so that the truncated cone of the photoresist 16 is formed. The light is transferred to an opal plate 14a, and a scatterer 14 made of an opal plate having a truncated cone shape is formed on the Zn diffusion region 12. At this time, the diameter of the bottom surface of the scatterer 14 in the shape of a truncated cone is set to 10 μm so as to match the size of the Zn diffusion region 12. Thus, the LE shown in FIG.
A D array is prepared (see FIG. 5).

As described above, according to the LED array of the present embodiment, the scatterer 14 made of a truncated cone-shaped opal plate is formed on the Zn diffusion region 12 constituting the LED, so that the GaAsP substrate 10 And Zn diffusion region 1
Even when light is emitted from a pn junction (light emitting portion) with a non-uniform emission pattern depending on the Zn concentration of the Zn diffusion region 12, the light is scattered in the process of passing through the scatterer. Therefore, it is possible to make the light amount unevenness of the non-uniform light emission pattern uniform. Accordingly, it is possible to form a higher quality image by suppressing the variation and anisotropy of the beam shape on the photosensitive surface of the print head.

The light scattered by the scatterer 14 is partially radiated from the truncated cone-shaped upper surface of the scatterer 14 in a direction substantially perpendicular to the GaAsP substrate 10 as shown by an arrow in FIG. Is done. Further, since the frusto-conical side surface of the scatterer 14 can be regarded as a new light source, light is also emitted from the frusto-conical side surface of the scatterer 14 as shown by an arrow in FIG. A part of the light emitted from this side also contributes in the direction perpendicular to the substrate. For this reason, not only for light emission obtained from the surface of the Zn diffusion region 12 but also for light emission obtained only from the upper surface of the scatterer 14 only in the shape of a truncated cone, a higher amount of light is emitted in the vertical direction of the GaAsP substrate 10. Obtainable. This is shown in the GaAsP substrate 1
When viewed from the 1 × optical system installed in the vertical direction of 0, LE
Since the emission angle of the emitted light from D appears to be concentrated in the center,
As a result, the utilization efficiency of light from the LEDs of the entire LED head to the photosensitive surface via the same-magnification imaging optical system is increased. Therefore, the light quantity of the beam on the image plane increases, the writing time of the print head can be shortened, and higher-speed printing can be realized, which is desirable as an LED array for an LED head.

[0034] In the first embodiment,
Z arranged in an array on the surface of the GaAsP substrate 10
Although the scatterer 14 made of a truncated cone-shaped opal plate is formed on the n-diffusion region 12, a scatterer having a cone shape may be used instead of the scatterer 14 having a truncated cone shape.

Also in this case, since the unevenness of the light amount of the non-uniform light emission pattern depending on the Zn concentration of the Zn diffusion region 12 can be made uniform, the variation and anisotropy of the beam shape on the photosensitive surface of the print head can be reduced. Suppression can form a higher quality image. Also, a part of the light emitted from the conical side surface of the scatterer, which can be regarded as a new light source, contributes in the direction perpendicular to the substrate, and the total surface area of this side surface is larger than the total surface area of the Zn diffusion region 12. A higher amount of light is obtained in the vertical direction of the GaAsP substrate 10 than the light emission obtained from Therefore, the beam light amount on the image plane increases, so that the writing time of the print head can be shortened, and higher-speed printing can be realized.

(Second Embodiment) FIG. 6 is a schematic sectional view showing an LED array for an LED print head according to a second embodiment of the present invention, and FIGS. FIG. 6 is a process cross-sectional view for describing the method for manufacturing the LED array for the LED print head of FIG.

An LED array for an LED print head according to the present embodiment corresponds to claims 1, 3, 4, and 5, and a scatterer is provided around a scatterer incorporated in each LED of the LED array. A reflection mirror is provided as an optical system for condensing light scattered by the light in a predetermined direction.

That is, as shown in FIG. 6, in the LED array for the LED print head according to this embodiment, Zn diffusion regions 22 having a diameter of 10 μm are formed in an array on the surface of the GaAsP substrate 20. I have. Then, an LED having a pn junction between the GaAsP substrate 20 and the Zn diffusion region 22 as a light emitting portion is formed. Note that the pitch of the Zn diffusion region 22 is 42.5 μm corresponding to 600 dpi. And these Zn diffusion regions 2
This embodiment is characterized in that a scatterer 24 made of a cylindrical opal plate having a thickness of 7 μm is formed on the scatterer 2 and a reflection mirror 26 is formed around the scatterer 24. .

The reflection mirror 26 is made of GaAsP.
A polyimide layer 28 formed on the substrate 20 and having an opening in the shape of an inverted truncated cone exposing the top surface of the cylindrical scatterer 24.
And an Al film 30 formed on the inner wall surface of the inverted frustoconical opening of the polyimide layer 26. Also,
Many particles that reflect light are dispersed inside the scatterer 24 made of the opal plate. Although not shown, an equal-magnification imaging optical system and a photosensitive drum are provided in the vertical direction of the GaAsP substrate 20. And Ga
Light emitted from a pn junction (light emitting portion) between the AsP substrate 20 and the Zn diffusion region 22 is condensed on a photosensitive drum via an equal-magnification imaging optical system, and a minute point image is formed on the photosensitive surface. Is formed.

Next, L for the LED print head shown in FIG.
A method of manufacturing the ED array will be described with reference to FIGS. First, Zn diffusion regions 22 having a diameter of 10 μm are formed in an array on the surface of a GaAsP substrate 20. Thus, an LED comprising a pn junction between the GaAsP substrate 20 and the Zn diffusion region 22 is formed. The pitch of the Zn diffusion region 22 is 42.5 μm corresponding to 600 dpi.
m.

Subsequently, a 7 μm-thick opal plate in which a large number of light-reflecting particles are dispersed is adhered on the GaAsP substrate 20 using a transparent adhesive, and then Zn is applied by photolithography. The opal plate is selectively anisotropically etched using a photoresist (not shown) patterned in accordance with the diffusion region 22 as a mask, and a scatterer 2 made of a cylindrical opal plate is formed on the Zn diffusion region 22.
4 is formed. At this time, the diameter of the bottom surface of the cylindrical shape of the scatterer 24 is set to 10 μm so that the Zn diffusion region 22 is formed.
(See FIG. 7).

Next, a polyimide layer 28 having a thickness of 35 μm is deposited on the entire surface of the substrate. Subsequently, the polyimide layer 28 is selectively etched using a photoresist (not shown) patterned into a predetermined shape by a photolithography technique as a mask, thereby exposing the upper surface of the cylindrical scatterer 24. An opening 32 is formed. At this time, the diameter of the bottom surface of the inverted frustoconical opening 32 is set to 10 μm so as to match the size of the upper surface of the cylindrical scatterer 24 and the upper surface of the inverted frustoconical opening 32. Has a diameter of 26 μm (see FIG. 8).

Finally, after depositing an Al film 30 having a thickness of 500 nm on the entire surface of the substrate including the opening portion 32 having an inverted truncated cone shape,
Al on the upper surface of the scatterer 24 in the opening 32 having an inverted truncated cone shape
The film 30 is selectively removed by etching. Thus, the inverted frustoconical opening 32 exposing the upper surface of the cylindrical scatterer 24 formed on the polyimide layer 28 and the Al film 30 formed on the inner wall surface of the inverted frustoconical opening 32 Then, the reflection mirror 26 surrounding the upper surface of the scatterer 24 is formed, and the LED array shown in FIG. 6 is manufactured (see FIG. 9).

As described above, according to the LED array according to the present embodiment, since the scatterer 24 made of a cylindrical opal plate is formed on the Zn diffusion region 22 constituting the LED, As in the case of the embodiment, Ga
Even when light is emitted from the pn junction (light emitting portion) between the AsP substrate 20 and the Zn diffusion region 22 in a non-uniform light emission pattern depending on the Zn concentration in the Zn diffusion region 22, the scatterer Since the light is scattered in the process of passing through the light source 24, it is possible to make the light amount unevenness of the non-uniform light emission pattern uniform. Therefore, when the light emitting diode elements are arranged in an array and used for a print head of an optical printer, a variation and anisotropy of the beam shape on the photosensitive surface of the print head are suppressed, and a higher quality image is formed. can do.

The light scattered by the scatterer 24 can be regarded as a new light source on the cylindrical upper surface of the scatterer 24, and a part of the light is scattered as shown by an arrow in FIG. 24 from the top of the cylindrical shape
Radiated in a direction perpendicular to the substrate 20. At the same time, a reflection mirror 26 as an optical system for condensing light in a predetermined direction is provided around the cylindrical scatterer 24, so that the GaAsP substrate 20 Even if the light is emitted in an oblique direction, the light is reflected by the reflection mirror 26 and travels in a direction substantially perpendicular to the GaAsP substrate 10 as indicated by an arrow in FIG. For this reason, even without the reflection mirror 26, even light that does not enter the unit-magnification imaging system can be effectively used without waste, and a higher amount of light can be obtained in the vertical direction of the GaAsP substrate 20. Accordingly, the beam light amount on the image plane increases, so that the writing time of the print head can be shortened, and higher-speed printing can be realized.

[0046]

As described above, according to the light emitting diode device of the present invention, the following effects can be obtained. That is, according to the light emitting diode element of the first aspect, the scatterer that scatters the light emitted from the light emitting section is provided on the light emitting section, so that the radiation pattern of the light emitting diode element is made uniform. Therefore, when these light-emitting diode elements are arranged in an array and used in a print head of an optical printer, variations in beam shape and anisotropy on the photosensitive surface of the print head are suppressed, and a higher-quality image is formed. It becomes possible to do.

According to the light emitting diode element of the second aspect, the scatterer for scattering the light radiated from the light emitting portion has a substantially conical or truncated cone shape.
When the light emitted from the light emitting section is scattered outside through the scatterer, the light emitted in the vertical direction of the substrate is the sum of the contributions of light emission from the conical side surface or the truncated conical upper surface and the side surface. Therefore, the ratio of the emitted light in the direction perpendicular to the substrate increases as compared with the case of the planar structure, and the emission intensity increases. Therefore,
When the light-emitting diode elements are arranged in an array and used for a print head of an optical printer, the amount of light transmitted to the photosensitive surface via the same-magnification imaging optical system increases, that is, the amount of beam on the image surface increases. Thus, it is possible to shorten the writing time of the print head and realize higher-speed printing.

According to the light emitting diode element of the third aspect, glass having particles dispersed therein, for example, opal glass, is used as the scatterer for scattering the light emitted from the light emitting portion. Since the light emitted from the light-emitting part is scattered by a large number of particles dispersed in the glass, even if the light is emitted in a non-uniform light-emitting pattern, the radiation pattern can be easily uniformized. be able to.

According to the light emitting diode element of the fourth aspect, since the optical system for condensing the light scattered by the scatterer in a predetermined direction is provided, radiation uniformized in the scatterer is provided. Of the light, it is possible to effectively use wasted light other than light in a predetermined direction, for example, a direction perpendicular to the substrate of the light emitting diode element. Therefore, when the light-emitting diode elements are arranged in an array and used in a print head of an optical printer, light deviating from the visual field power of the unity-magnification imaging optical system is also combined, and the radiated light from the scatterer is efficiently emitted. Since it can be used, the light amount of the beam on the image plane increases, the writing time of the print head can be shortened, and higher-speed printing can be realized.

According to the light emitting diode element of the fifth aspect, as the optical system for condensing the light scattered by the scatterer in a predetermined direction, the reflection mirror is provided around the scatterer. Of the scattered light uniformized in the scatterer, light radiated in a predetermined direction, for example, in a direction other than the substrate vertical direction of the light emitting diode element, can be bent in the substrate vertical direction. Most of the converted radiation can be effectively used without waste. Therefore, the effect of the light emitting diode device according to claim 4 can be easily achieved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an LED array for an LED print head according to a first embodiment of the present invention.

FIG. 2 is a process cross-sectional view (part 1) for describing the method for manufacturing the LED array for the LED print head in FIG.

FIG. 3 is a process sectional view (part 2) for describing the method for manufacturing the LED array for the LED print head in FIG.

FIG. 4 is a process sectional view (part 3) for describing the method for manufacturing the LED array for the LED print head in FIG.

FIG. 5 is a process sectional view (part 4) for explaining the method for manufacturing the LED array for the LED print head in FIG.

FIG. 6 is a schematic sectional view showing an LED array for an LED print head according to a second embodiment of the present invention.

FIG. 7 is a process sectional view (part 1) for describing the method for manufacturing the LED array for the LED print head in FIG.

FIG. 8 is a process sectional view (part 2) for describing the method for manufacturing the LED array for the LED print head in FIG.

FIG. 9 is a process sectional view (part 3) for describing the method for manufacturing the LED array for the LED print head in FIG.

FIG. 10 is a schematic cross-sectional view including a photosensitive drum and an optical system of a writing system of a conventional optical printer.

FIG. 11 is a plan view showing a conventional LED array.

FIG. 12 is a sectional view taken along line AA of the LED array of FIG. 11;

FIG. 13 is a schematic sectional view showing a conventional LED.

[Explanation of symbols]

 Reference Signs List 10 GaAsP substrate 12 Zn diffusion region 14 Scattering body made of truncated cone-shaped opal plate 14a Opal plate 16 Photoresist 20 GaAsP substrate 22 Zn diffusion region 24 Scattering body made of cylindrical opal plate 26 Reflection mirror 28 Polyimide layer 30 Al film 32 Inverted truncated cone-shaped opening 40 LED light source 42 Light emitted from LED light source 44 1 × imaging optical system 46 Light passing through 1 × imaging optical system 48 Photosensitive drum 50 Semiconductor substrate 52 First made of n-type GaAs Semiconductor layer 54 n-type AlGaAs second semiconductor layer 56 p-type AlGaAs third semiconductor layer 58 protective film 60a, 60b common electrode 62 individual electrode 70 n-GaAs substrate 72 n-InGaAlP cladding layer 74 InGaAlP activity Layer 76 p-InGaAlP cladding Layer 78 p-InGaP cap layer 80 n-InGaAlP current blocking layer 82 p-GaAlAs current diffusion layer 84 p-GaAs contact layer 86 p-side electrode 88 n-side electrode

Claims (5)

[Claims] 1. A light-emitting diode element, wherein a scatterer for scattering light emitted from the light-emitting part is provided on a light-emitting part of the light-emitting diode. 2. The light emitting diode device according to claim 1, wherein the scatterer has a substantially conical shape or a truncated cone shape. 3. The light emitting diode device according to claim 1, wherein said scatterer is made of glass having particles dispersed therein. 4. The light-emitting diode device according to claim 1, further comprising an optical system for condensing light scattered by the scatterer in a predetermined direction. 5. The light emitting diode device according to claim 4, wherein said optical system is a reflection mirror provided around said scatterer.