JP2000012973A - Two-dimensional light emitting device array, image display apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce parasitic capacity and electric resistance of wiring without complicating the driving sequence. SOLUTION: Light emitting devices 34, respectively having first and second electrodes, are disposed two-dimensionally in a long region. First wiring 40 connected to the first electrodes as lines which is formed in the direction of longer sides, and second wiring 42 connected to the second electrodes as rows which is formed in the direction of shorter sides are connected in the form of a matrix to form a light emitting device array. In this case, the light emitting device array is divided into plural blocks, which can be driven independently. Line wiring and row wiring are arranged for the light emitting device array in each of the divided plural blocks, and the lead wire of the line wiring is led out in the direction of the row.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional light-emitting element array used as a light source for a laser printer, a laser display, optical communication, an optical signal processing device, and the like, and an image display device using the two-dimensional light-emitting element array. More specifically, the present invention relates to a matrix wiring structure of a two-dimensional light emitting element array, and an image display device and an image forming apparatus using the two-dimensional light emitting element array as a light source.

[0002]

2. Description of the Related Art Heretofore, a method has been proposed in which matrix wiring is formed for a two-dimensional light-emitting element array in which light-emitting elements are two-dimensionally arranged to reduce the number of drive circuits (Japanese Patent Laid-Open No. Sho 61).
-31271). Here, the arrangement of the light emitting elements 200 in the light emitting element array is such that light emitting element rows slightly inclined with respect to the sub-scanning direction are continuously arranged in the main scanning direction as shown in FIG. , Matrix wiring is formed for the rows and columns of the light emitting element array. Here, the cathode wiring 202 is provided in the row direction, and the anode wiring 204 is provided in the column direction. Reference numeral 206 denotes a cathode lead wiring, and reference numeral 208 denotes an anode lead wiring. Such a wiring will be referred to as a vertical and horizontal matrix wiring. In this vertical and horizontal matrix wiring, there is
All the light emitting elements in one row can be driven independently, but as the number of light emitting elements in the row direction (main scanning direction) increases, the number of light emitting elements connected to one row wiring increases, As a result, the capacitance becomes large, causing a problem that the current waveform at the time of pulse driving becomes dull or that pulse driving at a relatively high frequency is almost impossible.

Further, when the number of light emitting elements connected to one row wiring increases and the row wiring lengthens, the electric resistance value increases and the current waveform at the time of pulse driving becomes dull or relatively low. Problems such as the inability to perform pulse driving at a high frequency occur. In an actual LED printer,
At a resolution of 1200 dpi (dot per inch), about 15000 light emitting element arrays are required. If these light emitting elements are arranged two-dimensionally, for example, in the column direction × row direction = 10 × 1500, the light emitting elements in the main scanning direction 1500 light-emitting elements are connected to the wiring, and 10 light-emitting elements are connected to the wiring in the sub-scanning direction. In this case, since the parasitic capacitance of one wiring in the main scanning direction is usually 150 pF or more, driving at a high frequency is not possible.

In order to solve this problem, FIG.
As shown in FIG. 1, an “oblique matrix wiring” in which row wirings for the light emitting element 200 are inclined obliquely has been proposed (
8-277165). In this method, since the anode wiring 210 and the cathode wiring 212 are wired in a matrix so as to form an “X character”, the number of light emitting elements connected to one wiring is, for example, as described above. Even when 15,000 light-emitting elements are arranged in a column direction × row direction = 10 × 1500, the number of anode wirings 210 and cathode wirings 212 is as small as 10 and the parasitic capacitance of the wirings is small. Therefore, the light emitting element array can be driven at a high frequency.

However, in this method, the anode wiring 2
10. Since both the cathode wiring 212 and the cathode wiring 212 are inclined with respect to the row direction, it is impossible to simultaneously emit light in only one row in the main scanning direction of the light emitting element array. Temporarily in the main scanning direction
If the wiring is driven to emit light in one row, the element in the other row at the intersection of the anode wiring 210 and the cathode wiring 212 also emits light, that is, all elements emit light. It is. In other words, the light emitting element arrays that can be driven independently at the same time are oblique light emitting element arrays connected to one cathode wiring (or anode wiring) for every ten wirings. In the light emitting element array provided with such oblique matrix wiring, there is also a problem that a driving sequence of the light emitting element becomes complicated.

In addition, in the case of the oblique matrix wiring, since the number of wirings is increased as compared with the conventional vertical and horizontal matrix wiring, the number of wire bonding and the like for making electrical connection is increased, and the manufacturing process becomes long. There are problems such as an increase in cost.

Further, when the number of wirings is increased, the number of channels of a driving IC for driving the wirings is also increased, resulting in a problem such as an increase in cost.

[0008]

In a light-emitting element array of m rows and n columns (m <n) in which an anode wiring and a cathode wiring are wired in a matrix, the conventional vertical and horizontal matrix wiring has a parasitic capacitance and an electric resistance value of the wiring. However, there is a problem that the driving can be performed only at a low frequency. Further, in the oblique matrix wiring that solves this problem, it is not possible to make all the light emitting elements in one row emit light at the same time. Since the element rows capable of emitting light are oblique, the driving sequence is complicated.

Further, the oblique matrix wiring has a problem that the number of wirings is increased as compared with the conventional vertical and horizontal matrix wirings, and the number of wire bonding and the like is increased.

[0010] The present invention has been made in view of such circumstances, and a two-dimensional light emitting element array in which a parasitic capacitance and an electric resistance value of a wiring are reduced without complicating a driving sequence. It is an object to provide an image display device and an image forming device using a light emitting element array.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, a light emitting device having a first electrode and a second electrode is two-dimensionally arranged in a long region. A first wiring as a row wiring formed in a long side direction connected to the first electrode and a second wiring as a column wiring formed in a short side direction connected to the second electrode are arranged. In a light-emitting element array connected in a matrix, the two-dimensionally arranged light-emitting element array is divided into a plurality of blocks that can be driven independently, and the light-emitting element arrays in each of the divided blocks are Row wiring and column wiring, and a lead line of the row wiring is drawn in the column direction.

[0012] According to a second aspect of the present invention, in the elongated region, the number of the light emitting elements having the first electrode and the second electrode is m in the short side direction and n in the long side direction. (Where m <n and m and n are integers) In a m-row and n-column light emitting element array two-dimensionally arranged, the light emitting element array satisfies m ≦ ki <n (ki is an integer). One block is divided into a (a is an integer) independently driven blocks of m rows and ki columns (i = 1, 2,..., A), and in each of the a blocks, the light emitting element array is The first electrode is connected to the first wiring formed in the long side direction, and the m second wirings are arranged in the short side direction while the m first wirings are arranged in the short side direction. Are connected to the second electrode, and ki pieces of the second wiring are arranged in the long side direction, and Second for drawing first the second wiring and the lead portion for leading out the first wiring
A lead portion is formed in the short side direction.

According to a third aspect of the present invention, in the two-dimensional light emitting element array according to the second aspect, ki in the m rows and ki columns of the light emitting element array in each block is constant. .

According to a fourth aspect of the present invention, in the two-dimensional light emitting element array according to the second aspect, the first lead portion is formed on one side in the short side direction, and the second lead portion is provided on the one side in the short side direction. It is characterized in that it is formed on the other side in the short side direction.

According to a fifth aspect of the present invention, in the two-dimensional light emitting element array according to the second aspect, the first lead portion and the second lead portion are formed on the same side in the short side direction. Features.

According to a sixth aspect of the present invention, in the two-dimensional light-emitting element array according to the second aspect, the first lead portion and the second lead portion are each one of the first lead portions and the second lead portions alternately arranged every one or more leads. It is characterized in that it is formed on one side and the other side in the side direction.

According to a seventh aspect of the present invention, in the two-dimensional light emitting element array according to the second aspect, the two-dimensionally arranged light emitting elements, the first wiring, the second wiring, and the first lead. And the second lead portion is formed on a common substrate.

According to an eighth aspect of the present invention, in the two-dimensional light-emitting element array according to the second aspect, on the short side direction where the first lead portion exists, and further in the long side direction. A third wiring portion is formed, and the third wiring portion is configured by m wires for each block, and each of the wires is the first wire.
It is characterized in that the wiring is periodically connected in a one-to-one correspondence.

According to a ninth aspect of the present invention, a light emitting element having a first electrode and a second electrode is two-dimensionally arranged in a long region, and a long side to which the first electrode is connected. A first wiring as a row wiring formed in
In a light emitting element array in which a second wiring as a column wiring formed in a short side direction connected to an electrode is connected in a matrix, a first lead portion for leading out the first wiring and the second wiring A second lead portion is formed in the short side direction, and a third wiring portion is formed in the long side direction on the side of the short side direction where the first lead portion exists, The third wiring portion is constituted by the same number of wires as the first wires, and is periodically connected to the first wires in a one-to-one correspondence.

According to a tenth aspect of the present invention, in the two-dimensional light emitting element array according to the second aspect, the second lead portion is located on a short side direction side and further in the long side direction. A fourth wiring portion is formed, wherein the fourth wiring portion includes a plurality of wirings, and each of the plurality of wirings is periodically connected to the second lead portion.

According to an eleventh aspect of the present invention, the light-emitting elements having the first electrode and the second electrode are two-dimensionally arranged in a long region, and the long side to which the first electrode is connected is provided. A first wiring as a row wiring formed in
In a light emitting element array in which a second wiring as a column wiring formed in a short side direction connected to an electrode is connected in a matrix, a first lead portion for leading out the first wiring and the second wiring A second lead portion is formed in the short side direction, and a fourth wiring portion is formed in the long side direction on the side of the short side direction where the second lead portion exists, The fourth wiring portion is divided into a plurality in the long side direction,
The plurality of divided wirings are connected to the second lead portion.

According to a twelfth aspect of the present invention, in the two-dimensional light emitting element array according to any one of the eighth and ninth aspects, the third wiring portion is formed so as to have a lower electric resistance than the first wiring. It is characterized by having done.

According to a thirteenth aspect of the present invention, in the two-dimensional light-emitting element array according to any one of the tenth and eleventh aspects, the fourth wiring portion is formed to have a lower electric resistance than the second wiring. It is characterized by having done.

[0024] The invention according to claim 14 is the invention according to claim 8,
13. The two-dimensional light-emitting element array according to any one of items 9 and 12, wherein the two-dimensionally arranged light-emitting elements, the first wiring, the second wiring, the first lead, the second lead, and The third wiring portion is formed on a common substrate.

[0025] The invention according to claim 15 is the invention according to claim 10,
14. The two-dimensional light-emitting element array according to any one of 11 and 13, wherein the two-dimensionally arranged light-emitting elements,
The wiring, the second wiring, the first lead portion, the second lead portion, and the fourth wiring portion are formed on a common substrate.

The invention according to claim 16 is the invention according to claim 8,
13. The two-dimensional light-emitting element array according to any one of items 9 and 12, wherein the two-dimensionally arranged light-emitting elements, the first wiring, the second wiring, the first lead, and the second lead are common. And the third wiring portion is formed on another substrate.

[0027] The invention described in claim 17 is based on claim 10,
14. The two-dimensional light-emitting element array according to any one of 11 and 13, wherein the two-dimensionally arranged light-emitting elements,
The wiring, the second wiring, the first lead portion, and the second lead portion are formed on a common substrate, and the fourth wiring portion is formed on another substrate.

The invention according to claim 18 is an image display device for displaying an image by driving a light source according to a video signal and scanning a light beam emitted from the light source on a display screen. The light source is a two-dimensional light emitting element array according to any one of claims 1 to 17.

According to a nineteenth aspect of the present invention, there is provided an image forming apparatus for driving a light source according to an image signal, irradiating a light beam emitted from the light source onto a photosensitive member, and forming an image on the photosensitive member. In the invention, the light source is a two-dimensional light emitting element array according to any one of claims 1 to 17.

According to the two-dimensional light emitting element array of the first to eighth, tenth, fourteenth, and fifteenth aspects, the laser array, which is a two-dimensionally arranged light emitting element array, is divided into a plurality of independent blocks. Performing row wiring and column wiring on the light emitting element arrays in each of the plurality of divided blocks;
Since the leader line of the row wiring was drawn in the column direction,
The lengths of the anode wiring, the anode lead wiring, the cathode wiring, and the cathode lead wiring can be shortened, so that the parasitic capacitance and electric resistance of the wiring can be reduced without complicating the driving sequence.

According to the two-dimensional light-emitting element array of the third aspect, the size of each independently driven block is fixed, so that the driving sequence of the wiring can be further simplified, and therefore the driving for driving the wiring is performed. The circuit can be simplified.

According to the two-dimensional light emitting element array of the ninth aspect, the third wiring portion is formed such that the same number of wires as the first wires are periodically connected to the first wires in a one-to-one correspondence. Therefore, the electric resistance value of the wiring (first wiring) can be reduced.

Further, since the number of channels of the drive circuit for driving the first wiring is the same as that of the third wiring section, the number of channels of the drive circuit for driving the first wiring can be reduced.

According to the two-dimensional light-emitting element array of the eleventh aspect, the fourth wiring portion is divided into a plurality of portions in the long side direction, and each of the divided wires is connected to the second wiring portion. , The electric resistance of the wiring (second wiring) can be reduced.

Further, since the number of channels of the driving circuit for driving the second wiring is the same as the number of wirings of the fourth wiring section, the number of channels of the driving circuit for driving the second wiring can be reduced.

According to the two-dimensional light emitting element array of the twelfth aspect, since the third wiring portion is formed so as to have a lower electric resistance than the first wiring, the electric resistance value of the wiring (first wiring) can be further increased. , Can be reduced.

According to the two-dimensional light emitting element array of the thirteenth aspect, since the fourth wiring portion is formed so as to have a lower electric resistance than the second wiring, the electric resistance value of the wiring (second wiring) can be further increased. , Can be reduced.

According to the two-dimensional light-emitting element array of the sixteenth aspect, the third wiring portion is formed on a substrate different from the components other than the third wiring portion including the light-emitting element. The wiring portion need not be formed in the substrate on which components other than the third wiring portion are formed, and the size of the substrate (chip) on which the light emitting element is formed can be reduced.

Further, the third wiring portion is formed within the substrate on which the third wiring portion is formed.
Since the degree of freedom in mounting is large, for example, by increasing the line width of the wiring constituting the wiring section, the electric resistance value of the wiring of the third wiring section can be significantly reduced.

The block size of the light emitting element array which can be independently driven can be determined only by the wiring structure of the substrate on which the third wiring portion is formed.

According to the two-dimensional light-emitting element array of the seventeenth aspect, the fourth wiring portion is formed on a substrate different from the components other than the fourth wiring portion including the light-emitting element. The wiring portion need not be formed in the substrate on which components other than the fourth wiring portion are formed, and the size of the substrate (chip) on which the light emitting element is formed can be reduced.

Further, the fourth wiring portion is formed within the substrate on which the fourth wiring portion is formed.
Since the degree of freedom in mounting is large, for example, by increasing the line width of the wiring constituting the wiring section, the electric resistance value of the wiring of the fourth wiring section can be significantly reduced.

The block size of the light emitting element array which can be independently driven can be determined only by the wiring structure of the substrate on which the fourth wiring portion is formed.

According to the image display device of the eighteenth aspect, since the two-dimensional light emitting element array in which the parasitic capacitance and the electric resistance value of the wiring are reduced is used as the light source, the resolution of the image can be improved.

According to the image forming apparatus of the nineteenth aspect, since the two-dimensional light emitting element array for reducing the parasitic capacitance and electric resistance of the wiring is used as the light source, the resolution of the image can be improved.

[0046]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First Embodiment of the Present Invention First, a two-dimensional light emitting element array using a surface emitting laser as a light emitting element will be described. FIG. 8 shows a laminated structure of a surface emitting laser. The stacked structure of this surface emitting laser is MOC
It is manufactured by crystal growth using a VD (Metal-Organic Chemical Vapor Deposition) apparatus. First,
A semi-insulating GaAs substrate 10 is set in an MOCVD apparatus, and an n-type GaAs buffer layer 12 (0.2
μm thickness, carrier concentration 2 × 10 ¹⁸ / cm ³ ), n-type Al _0.3 Ga
_0.7 As / Al _0.9 Ga _0.1 As multilayer mirror 14 (64.5 nm (upper layer) / 5
7.6nm (lower layer) × 40.5 period, carrier concentration 2 × 10 ¹⁸ / cm ³ )
, The active region 16 is sequentially grown.

The active region 16 is made of Al_0.6Ga_0.4As spacer layer
(89.8nm, undoped) and Al_0.11Ga _0.89As / Al_0.3Ga_0.7
As (Quantum well layer / barrier layer 8nm / 5nm × 4 periods, non-dose
) Quantum well structure layer and Al_0.6Ga_0.4As spacer layer (89.
8 nm, non-doped).

On the active region 16, p-type Al for selective oxidation is formed.
_0.98 Ga _0.02 As layer 18 (65.4 nm, carrier concentration 2 × 10 ¹⁸ / c
m ³ ) and p-type Al _0.9 Ga _0.1 As / Al _0.3 Ga
_0.7 As multilayer mirror 20 (64.5 nm / 57.6 nm × 29.5 periods, carrier concentration 2 × 10 ¹⁸ / cm ³ ), p-type contact layer 22 (9
nm and a carrier concentration of 1 × 10 ¹⁹ / cm ³ ) are sequentially grown. Here, the laminated interface between the multilayer mirrors 14 and 20 was a graded layer whose composition was gradually changed to reduce the electric resistance.

The thickness t _i of each layer of the multilayer mirrors 14 and 20
Is for a laser wavelength λ (780 nm here)
t _i = λ / (4 · _ni ) is satisfied (n
_i is the refractive index of each layer), and high reflectance is achieved. The thickness of the active region 16 is determined by the thickness t _{i of} each layer and the refractive index n.
Total multiplied by _i values t _i × n _i is set equal to lambda, and serves as a laser resonator.
After growing such a laminated structure, the GaAs substrate 10 is
The area 24 other than the area where the laser element is formed on the GaAs substrate 10 is removed by etching in order to form the post shape (convex shape) of the surface emitting laser after taking out from the D apparatus.
The etching depth was such that the n-type GaAs buffer layer 12 was exposed on the surface.

Next, the sample was placed in a steam atmosphere at 400 ° C.
P-type Al for insertion and selective oxidation_0.98Ga _0.02Outer circumference of As layer 18
To narrow the current path in the surface emitting laser
To form a doughnut-shaped insulating region. Not oxidized
Of the hole in the doughnut-shaped insulating region, that is, the current path
The diameter was Φ5 μm. The arrangement of the laser elements is
In particular, 3 rows and 600 columns were arranged at a pitch of 30 μm.

Next, an element isolation groove 26 was formed in order to isolate an element from a surface emitting laser in an adjacent row, and then a protective film SiNx 28 was formed on the side surface of the post-shaped surface emitting laser.

Finally, the AuGe alloy is formed as the n-type electrode 30 (corresponding to the first electrode of the present invention), and the Au / Ti alloy is formed as the p-type electrode 32 (corresponding to the second electrode of the present invention). did. In this way, a surface emitting laser element 34 is manufactured, and Ga
A laser array in which the surface emitting laser elements 34 are arranged in a matrix on the As substrate 10 was manufactured. In this laser array, surface-emitting laser elements 34 as light-emitting elements are two-dimensionally arrayed in a long region in such a manner that m pieces are arranged in the short side direction and n pieces (m <n) in the long side direction. M rows n
This is a light emitting element array of columns (m and n are integers).

In this embodiment, the laser array
One block satisfying ≤ki <n (ki is an integer) is driven independently by m rows and ki columns (i = 1, 2,..., A).
Is an integer) number of blocks, and the divided a
Row wirings (cathode wirings) and column wirings (anode wirings) are applied to the laser arrays (light emitting element arrays) in each block, and the lead lines of the row wirings are drawn out in the column direction. Specifically, as shown in FIG. 1, a matrix wiring in which a block unit which can be independently driven was formed in three rows and three columns was formed.
In the present embodiment, the block unit is 3 rows and 3 columns, but each block size may be unequal (ki has a different value).

The matrix wiring is formed by first forming a cathode wiring 40-r (r = 1, 1) in the row direction with respect to the n-type electrode 30.
2,..., N) (corresponding to the first wiring of the present invention) are formed of a gold material so as to connect the laser arrays arranged in three rows and three columns in each block. For example, regarding the block 1, the cathode wirings 40-1, 40-2, 40-3
Are formed so as to be connected to a laser array of three rows and three columns.

Next, a cathode lead wire 44 (corresponding to a first lead portion of the present invention) for leading out the cathode wire 40-r in the row direction in the column direction is formed (44-1, 44-2, 41-2).
..., 44-600). Next, the cathode lead wiring 44 includes:
Cathode lead wiring 46 for connecting to an external drive circuit
(46-1, 46-2, ..., 46-600). Here, an insulating film (SiNx) 50 was formed at the intersection of the cathode wiring 40-r in the row direction and the cathode lead wiring 44 in the column direction, and was electrically separated.

Next, the region 24 other than the laser device is buried with polyimide, and the anode wiring 42 (42-1, 4) is formed thereon.
2-2,..., 42-600) (corresponding to the second wiring of the present invention). The anode wiring 42 is connected to an anode lead wiring 48 (48-
1, 48-2,..., 48-600) (corresponding to the second lead portion of the present invention). The surface emitting laser array manufactured as described above has, for example, one out of three cathode lead wires in the column direction,
, 44-9,..., 44-3p (p is a natural number), and all the anode lead wires 42 are driven, whereby all the surface emitting laser elements 34-1-p in the first row are driven.
, 34-1-600 could be independently driven at the same time.

According to the two-dimensional light-emitting element array according to the first embodiment of the present invention, the laser array, which is a two-dimensionally arranged light-emitting element array, is divided into a plurality of blocks that can be driven independently, and divided. Row wiring and column wiring for the light emitting element arrays in each of the plurality of blocks, and the lead lines of the row wiring are drawn in the column direction, so that the anode wiring, the anode lead wiring and the cathode wiring, the cathode Since both the lengths of the lead wires can be shortened, the parasitic capacitance and the electric resistance value of the wires can be reduced, the voltage drop during driving can be prevented, and the surface of the two-dimensional light emitting element array can be prevented. The light emitting laser array can be driven at a high frequency.

Further, since the ki of the block size (m rows and ki columns) of the laser array is made constant, that is, the size of the block size is made constant, the driving sequence of the wiring can be simplified, and therefore the wiring can be simplified. Can be simplified.

Further, since the parasitic capacitance and the electric resistance value of the wiring can be reduced, the power consumption during driving can be reduced.

In this embodiment, the cathode wiring is a row wiring and the anode wiring is a column wiring. However, it is needless to say that the same effect can be obtained by using the cathode wiring as a column wiring and the anode wiring as a row wiring. .

In this embodiment, the cathode lead wires are formed on one side of the laser array which is the light emitting element array in the short side direction, and the anode lead wires are formed on the other side of the laser array in the short side direction. However, the same effect can be obtained by forming the cathode lead wiring and the anode lead wiring on the same side in the short side direction of the laser array.

Further, a cathode lead wiring and an anode lead wiring are
The same effect can be obtained by alternately forming one or a plurality of laser arrays on one side and the other side in the short side direction of the laser array.

In this embodiment, the light emitting device is a surface emitting laser. However, any semiconductor light emitting device may be used.
Needless to say, the present invention can be applied to an element array.

Second Embodiment of the Present Invention Next, the wiring structure of a two-dimensional light emitting element array according to a second embodiment of the present invention will be described. In the first embodiment of the present invention, the block size of the laser array that can be independently driven is 3 rows and 3 columns, but the size in the column direction can be freely changed as long as it is 3 columns or more. In the second embodiment of the present invention, a case will be described in which the block size of a laser array that can be driven independently is 3 rows and 6 columns.

As in the case of the first embodiment of the present invention, as shown in FIG. 8, a stacked structure of a surface emitting laser array is manufactured by using an MOCVD apparatus, and thereafter, selective oxidation is performed to perform laser oxidation. A current confinement structure was formed. Then, after forming an element isolation groove as in the first embodiment of the present invention, an electrode was formed. The arrangement of the surface emitting laser elements in the laser array is 3 rows and 600 columns.

A wiring structure as shown in FIG. 2 was formed on this laser array. In the formation method, first, three cathode wires 40a in the row direction are formed on the n-type electrode 30 so as to be connected to the laser elements of the laser array for each block of 3 rows and 6 columns for each row. In this embodiment, there are 100 blocks of the laser array of 3 rows and 6 columns, but FIG. 2 shows only two blocks for convenience.

Next, a cathode lead wire 44a for drawing out the cathode wire 40a in the row direction in the column direction is formed. An insulating film (SiNx) 50a was formed at the intersection of the cathode wiring 40a in the row direction and the cathode lead wiring 44a in the column direction, and was electrically separated. Next, the region 24 other than the laser element was buried with polyimide, and the anode wiring 42a was formed thereon. An anode lead wire 48a for connection to an external drive circuit was formed on each anode wire 42a.

According to the two-dimensional light-emitting element array according to the second embodiment of the present invention, the matrix wiring is formed so as to increase the block size of the independently driven light-emitting element array. Compared with the embodiment, the number of cathode lead wires can be reduced to half.

Therefore, the driving I for driving the cathode wiring
The number of C channels can be reduced by half, and the number of cathode lead wires can be reduced, so that the space for wire bonding and the like can be increased.

Third Embodiment of the Present Invention Next, the wiring structure of a two-dimensional light-emitting element array according to a third embodiment of the present invention will be described. In this embodiment, a surface emitting laser array similar to that of the second embodiment is manufactured. The arrangement of the surface emitting laser elements in the laser array is also 3 rows and 600 columns as in the second embodiment.

A matrix wiring as shown in FIG. 3 is formed for this laser array. First, the formation method
Cathode wirings 40b-1, 40b-2, 40b as row wirings
-3,..., 40b-300 and the cathode wiring pads 60b-1, 60b-2, 60b-3,.
0b-300 (corresponding to the third wiring of the present invention) are simultaneously formed as shown in FIG. Cathode wiring 40b-
Each of 1, 40b-2, 40b-3,..., 40b-300 is formed so as to connect surface emitting laser elements arranged in three rows and six columns.

Each of the cathode wiring pads 60b is connected to the laser array 3
Each cathode wiring 40 having a length equal to or longer than the length including the column
In the present embodiment, the wiring is formed so as to have a line width wider than that of the cathode wiring 40b so that the electric resistance becomes lower than that of the cathode wiring 40b.

Next, the cathode lead wires 44b in the column direction
, 44b-600 are formed for each row of the laser array, and are connected to the cathode wiring pads 60b. This connection method is based on the cathode lead wiring 44b-1.
And the cathode lead wiring 44b-4 are connected to the cathode wiring pad 60b-
1 and the cathode lead wiring 44b-2 and the cathode lead wiring 44b-5 are connected to the cathode wiring pad 60b-2, and are sequentially and periodically connected as shown in FIG.

According to the two-dimensional light emitting element array according to the third embodiment of the present invention, similarly to the second embodiment, the block size of the independently driven light emitting element array is increased,
In addition, since the matrix wiring is formed such that a cathode wiring pad of a predetermined length is connected to each cathode wiring by a cathode lead, the number of channels of a driving IC for driving the cathode wiring can be reduced, and the cathode wiring pad is smaller than the cathode wiring. Also, since the line width can be made wider, the electric resistance can be reduced, and the electric resistance of the cathode wiring can be made smaller than in the second embodiment.

Fourth Embodiment of the Present Invention Next, a wiring structure of a two-dimensional light emitting element array according to a fourth embodiment of the present invention will be described with reference to FIG. As shown in the figure, the two-dimensional light-emitting element array according to the present embodiment includes a laser array chip 70 and a printed wiring board 72 on which the laser array chip 70 is installed. Laser array chip 70
Is a surface emitting laser which is divided into a plurality of blocks which can be driven independently and which is provided with a cathode wiring 40c as a row wiring and an anode wiring 42c as a column wiring for each block, and as a light emitting element of 3 rows and 600 columns. An element 34 is formed. A cathode lead wire 44c connected to each cathode wire 40c, and an anode lead wire 48c connected to each anode wire 42c,
There are 600 each. The method of fabricating the matrix wiring structure is the same as that of the first embodiment, and a duplicate description will be omitted.

The laser array chip 7 is mounted on the printed wiring board 72 having the bonding pads 74 corresponding to the cathode lead wires 44c of the laser array chip 70 on a one-to-one basis.
0 is adhered. Then, the cathode lead wire 44c and the bonding pad 74 were connected by the bonding wire 80.

The printed wiring board 72 includes bonding pads 74, bonding wires 76 for connecting the bonding pads 74 for every three bonding pads 74, bonding pads 74 and bonding wires 7.
6 are formed by electrode pads 78 connected by the same.
The coupling wiring 76 is formed by the insulating film 82 so that the intersection does not contact. That is, the bonding pads 74-1 and 74-4 are connected to the electrode pad 78-1, the bonding pads 74-2 and 74-5 are connected to the electrode pad 78-2, and the bonding pad 74-3 is connected. And 74-6 are connected to the electrode pad 78-3, and thereafter, similarly. The block size of the laser array which can be independently driven by this wiring structure is 3 rows 6
Become a column. Finally, the driving IC and the electrode pad 78 are electrically connected.

According to the fourth embodiment of the present invention, the surface emitting laser element 3 as a two-dimensionally arranged light emitting element
4, a cathode wire 40c as a first wire, an anode wire 42c as a second wire, and a cathode lead wire 44c as a first lead portion. Anode lead wire 44c as second lead portion
Are formed on a common substrate, and the wiring (third wiring portion) such as the bonding pad 74, the coupling wiring 76, and the electrode pad 78 connected to the cathode lead wiring 44c is formed on another substrate. Similarly to the embodiment, the number of channels of the driving IC for driving the cathode wiring can be reduced, the resistance value of the cathode wiring of the laser array can be reduced, and the cathode wiring pad having a complicated structure Need not be manufactured in the laser array chip 70, the size of the laser array chip can be reduced, and the number of chips that can be collected from one laser structure wafer can be increased.

Further, since the wiring in the printed circuit board has a large degree of freedom in mounting, for example, by increasing the line width of the wiring, the electric resistance value thereof can be significantly reduced as compared with the wiring in the laser array.

The block size of the laser array that can be driven independently can be arbitrarily determined only by the wiring structure of the printed circuit board.

In this embodiment, the wiring (third wiring part) connected to the cathode lead wiring as the first lead part is formed by other components of the two-dimensional light emitting element array including the light emitting element (surface emitting laser element). Is formed on a substrate different from the substrate on which the substrate is formed, but the wiring (fourth wiring part) connected to the anode lead wiring as the second lead part includes a light emitting element (surface emitting laser element). The same effect can be obtained by forming it on a substrate different from the substrate on which other components of the two-dimensional light emitting element array are formed.

Fifth Embodiment of the Present Invention A wiring structure of a two-dimensional light-emitting element array according to a fifth embodiment of the present invention will be described with reference to FIGS. The wiring structure of the two-dimensional light emitting element array shown in FIG. 5 is a modification of the wiring structure of the two-dimensional light emitting element array according to the first embodiment shown in FIG. The cathode lead wires are drawn out of the cathode wires for each row of the laser array without being divided into a plurality of blocks that can be driven by the laser array.

As shown in FIG. 5, for a laser array in which surface emitting laser elements are arranged in three rows and 600 columns, three cathode wirings 40d-1, 40d-2, and 40d-3 and 600 anode wirings 42d are provided. -1,42d-2, ..., 42d-600
To form These three cathode wirings 40d-1, 40d-
600 cathode lead wires 46 for 2,40d-3
, 46d-2,..., 46d-600 are formed.
The cathode lead wiring 46d is connected to a circuit for driving the cathode lead wiring 46d.

In the wiring structure of the two-dimensional light emitting element array shown in FIG. 5, since one cathode wiring 40d is formed with 200 cathode lead wirings 46d, the electrical connection of the wiring connecting the drive circuit and the surface emitting laser element is made. The resistance value can be reduced.

In the wiring structure of the two-dimensional light emitting element array shown in FIG. 5, the cathode lead wires 46d-1, 46d-4,..., 4 connected to the same cathode wire, for example, 40d-1.
6d-598 are all driven at the same timing. Therefore, all of these wirings can be connected. Thereby, the number of channels of the driving circuit can be reduced. FIG. 6 shows the wiring structure. Here, the case where the number of channels of the drive circuit is the minimum of three will be described.

In this laser array, when forming the cathode wiring 40d in the row direction, the cathode wiring pad 60d in the row direction is formed.
After that, a cathode lead wire 46d in the column direction was formed, and the cathode wire 40d and the cathode wire pad 60d were periodically connected. That is, this connection is made by the cathode lead wires 46d-1, 46d-4, 46d-7,..., 46d-5.
98 are connected to the cathode wiring pad 60d-1, and the cathode lead wirings 46d-2, 46d-5, 46d-8,.
−599 to the cathode wiring pad 60d-2, and the cathode lead wirings 46d-3, 46d-6, 46d-9,.
6d-600 was connected to the cathode wiring pad 60d-3. The intersection of the wiring in the row direction and the wiring in the column direction is insulated with an insulating film interposed therebetween.

The wiring width of the cathode wiring pad 60d is formed so as to be several times wider than the cathode wiring 40d, and its electric resistance is small.

By forming the wiring structure of the two-dimensional light emitting element array in this manner, the surface emitting laser elements
The number of channels of the circuit for driving the laser array arranged in the 0 row is three for the cathode wiring and 60 for the anode wiring.
It became 0 pieces. The number of channels of the driving IC for driving the cathode wiring was significantly reduced.

In this embodiment, the cathode lead wiring 46 d
Are provided with the cathode wiring pad 60d, but the same effect can be obtained by providing the anode wiring pad (corresponding to the fourth wiring portion of the present invention) to the anode lead wiring 48d instead of the cathode lead wiring 46d. Needless to say, there is.

In this embodiment, the cathode wiring pad 60d is provided only for the cathode lead wiring 46d.
A cathode wiring pad 60d and an anode wiring pad may be provided for the cathode lead wiring 46d and the anode lead wiring 48d, respectively. In this case, although the 600 anode wirings 42d cannot be driven completely independently, the present invention can be applied to a case where the anode wirings 42d are simultaneously driven periodically to emit light from the laser element.

Further, in this embodiment, the cathode lead wires are drawn out one by one for each array of the laser array. However, as shown in FIG.
The cathode lead wires 46e-1, 46e-2, and 46e-3 of the laser array connected to 0e-2 and 60e-3 and the laser array may be drawn out for each array. In this wiring structure, the electric resistance of the wiring connecting the drive circuit and the laser element can be further reduced as compared with the wiring structure shown in FIG.

Sixth Embodiment of the Present Invention An image display device according to a sixth embodiment of the present invention will be described with reference to FIGS. The image display device according to the present embodiment uses, as a light source, a surface emitting laser array 90 (FIG. 9) of 3 rows and 600 columns manufactured similarly to the first embodiment (FIG. 1). . As shown in FIG. 9, a surface emitting laser array 90 used for an image display device
Indicates that the arrangement position (column direction) of the laser element in each row is the row direction,
In other words, each laser element is shifted in parallel so as to form a predetermined angle with respect to the base line 92, and each laser element is arranged in three rows and 600 columns so that the light emitting point arrays obtained by projecting the light beam spots of the respective laser elements onto the base line 92 are arranged at equal intervals. Is formed. The arrangement pitch of the row wiring and the column wiring is 30 μm. The laser beam emitted from the surface-emitting laser array 90 was magnified 10 times using optical lenses 94 and 98 and an f-θ lens 100 and projected onto a screen 102 as shown in FIG. The luminous point sequence projected on the screen 102 was arranged at a pitch of 0.3 mm. Further, by inserting a rotating polyhedral mirror 96 into the optical path of the laser beam and rotating it, the laser beam could be scanned on the screen 102. The light emission of the surface emitting laser array 90 was controlled by the drive circuit 104 so as to correspond to the video signal. This allows
The image could be created on the entire screen.

According to the image display apparatus of the sixth embodiment of the present invention, the two-dimensional light-emitting element array for reducing the parasitic capacitance and electric resistance of the wiring is used as the light source, so that the resolution of the image is improved. Can be achieved.

Seventh Embodiment of the Present Invention FIG. 11 shows a configuration of an image forming apparatus according to a seventh embodiment of the present invention. In the image forming apparatus according to the present embodiment,
The surface emitting laser arrays 90 used in the sixth embodiment were connected in a 6-chip row direction to form a multi-head laser array 110 having 3 rows and 3600 columns, and this multi-head laser array 110 was used as a light source.

In FIG. 11, the laser beam emitted from the multi-head laser array 110 is
2. Irradiation was performed on the photosensitive drum 118 via the reflection mirror 114 and the optical lens 116. The driving circuit 120 caused the multi-head laser array 110 to emit light in accordance with the image signal in accordance with the rotation of the photosensitive drum 118.

As a result, an electrostatic latent image for printing an image could be formed on the photosensitive drum 118.

According to the image forming apparatus of the seventh embodiment of the present invention, since the two-dimensional light emitting element array for reducing the parasitic capacitance and electric resistance of the wiring is used as the light source, the resolution of the printed image can be reduced. Improvement can be achieved.

[0099]

As described above, according to the two-dimensional light-emitting element arrays according to the first to eighth, tenth, fourteenth, and fifteenth aspects, the laser array, which is a two-dimensionally arranged light-emitting element array, can be used. It is divided into a plurality of blocks that can be independent, and the row and column wirings are applied to the light emitting element arrays in each of the plurality of divided blocks, and the lead lines of the row wiring are drawn in the column direction. The lengths of the wiring, the anode lead wiring, the cathode wiring, and the cathode lead wiring can be shortened, so that the parasitic capacitance and the electric resistance value of the wiring can be reduced without complicating the driving sequence.

According to the two-dimensional light-emitting element array of the third aspect, since the size of each independently driven block is fixed, the drive sequence of the wiring can be further simplified, and therefore the drive for driving the wiring can be simplified. The circuit can be simplified.

According to the two-dimensional light-emitting element array of the ninth aspect, the third wiring portion is formed such that the same number of wires as the first wires are periodically connected to the first wires in a one-to-one correspondence. Therefore, the electric resistance value of the wiring (first wiring) can be reduced.

Further, since the number of channels of the drive circuit for driving the first wiring is the same as that of the third wiring portion, the number of channels of the drive circuit for driving the first wiring can be reduced.

According to the two-dimensional light emitting element array of the eleventh aspect, the fourth wiring part is divided into a plurality of parts in the long side direction, and each divided wiring is connected to the second wiring part. , The electric resistance of the wiring (second wiring) can be reduced.

Further, since the number of channels of the drive circuit for driving the second wiring is the same as that of the fourth wiring section, the number of channels of the drive circuit for driving the second wiring can be reduced.

According to the two-dimensional light emitting element array of the twelfth aspect, since the third wiring portion is formed so as to have a lower electric resistance than the first wiring, the electric resistance value of the wiring (first wiring) can be further increased. , Can be reduced.

According to the two-dimensional light emitting element array of the thirteenth aspect, since the fourth wiring portion is formed so as to have a lower electric resistance than the second wiring, the electric resistance value of the wiring (second wiring) can be further increased. , Can be reduced.

According to the two-dimensional light emitting element array of the sixteenth aspect, since the third wiring portion is formed on a substrate different from the components other than the third wiring portion including the light emitting element, the third wiring portion is formed. The wiring portion need not be formed in the substrate on which components other than the third wiring portion are formed, and the size of the substrate (chip) on which the light emitting element is formed can be reduced.

Further, the third wiring portion is formed within the substrate on which the third wiring portion is formed.
Since the degree of freedom in mounting is large, for example, by increasing the line width of the wiring constituting the wiring section, the electric resistance value of the wiring of the third wiring section can be significantly reduced.

The block size of the light emitting element array which can be independently driven can be determined only by the wiring structure of the substrate on which the third wiring portion is formed.

According to the two-dimensional light emitting element array of the seventeenth aspect, since the fourth wiring portion is formed on a substrate different from the components other than the fourth wiring portion including the light emitting element, the fourth wiring portion is formed. The wiring portion need not be formed in the substrate on which components other than the fourth wiring portion are formed, and the size of the substrate (chip) on which the light emitting element is formed can be reduced.

Further, the fourth wiring portion is formed within the substrate on which the fourth wiring portion is formed.
Since the degree of freedom in mounting is large, for example, by increasing the line width of the wiring constituting the wiring section, the electric resistance value of the wiring of the fourth wiring section can be significantly reduced.

The block size of the light emitting element array that can be driven independently can be determined only by the wiring structure of the substrate on which the fourth wiring portion is formed.

According to the image display device of the eighteenth aspect, since the two-dimensional light emitting element array for reducing the parasitic capacitance and electric resistance of the wiring is used as the light source, the resolution of the image can be improved.

According to the image forming apparatus of the nineteenth aspect, since the two-dimensional light emitting element array for reducing the parasitic capacitance and electric resistance of the wiring is used as the light source, the resolution of the image can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a wiring structure of a two-dimensional light emitting element array according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a wiring structure of a two-dimensional light emitting element array according to a second embodiment of the present invention.

FIG. 3 is an explanatory view showing a wiring structure of a two-dimensional light emitting element array according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a wiring structure of a two-dimensional light emitting element array according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a wiring structure of a two-dimensional light-emitting element array according to a fifth embodiment of the present invention.

FIG. 6 is an explanatory view showing a modification of the wiring structure of the two-dimensional light emitting element array according to the fifth embodiment of the present invention shown in FIG.

FIG. 7 is an explanatory view showing a modification of the wiring structure of the two-dimensional light-emitting element array according to the fifth embodiment of the present invention shown in FIG.

FIG. 8 is a sectional structural view of a surface emitting laser array.

FIG. 9 is an explanatory diagram showing an arrangement of a surface emitting laser array and a wiring structure used in a sixth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a configuration of an image display device according to a sixth embodiment of the present invention.

FIG. 11 is a schematic configuration diagram illustrating a configuration of an image forming apparatus according to a seventh embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a wiring structure of a conventional light emitting element array.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semi-insulating GaAs substrate 12 n-type buffer layer 14 n-type multilayer mirror 16 Active region 18 AlAs selective oxidation layer 20 p-type multilayer mirror 22 p-type contact layer 26 element isolation groove 28 protective film 30 n-type electrode 32 p-type Electrode 34 Surface emitting laser element 40 Cathode wiring 42 Anode wiring 44 Cathode lead wiring 46 Cathode lead wiring 48 Anode lead wiring

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C162 AE28 AF06 AH27 AH30 FA17 FA18 2C362 AA15 5F041 AA02 AA43 BB31 CA91 CA93 FF03 FF06 FF13 FF14 FF16 5F073 AB02 BA01 BA07 BA08 BA09 CB22 EA29 GA37 GA38

Claims (19)

[Claims] 1. A light emitting element having a first electrode and a second electrode is two-dimensionally arranged in an elongated region,
A first wiring as a row wiring formed in a long side direction connected to the first electrode and a second wiring as a column wiring formed in a short side direction connected to the second electrode are formed in a matrix. In the connected light emitting element array, the two-dimensionally arranged light emitting element array is divided into a plurality of blocks that can be driven independently, and row wiring is performed on the light emitting element arrays in each of the plurality of divided blocks. A two-dimensional light-emitting element array, wherein a lead line of a row wiring is drawn in a column direction. 2. A light-emitting element having a first electrode and a second electrode has a length m in a short side direction in a long region.
And m (n is an integer and m <n, where m is an integer) two-dimensionally arranged m rows and n columns in the long side direction, wherein the light emitting element array has m ≦ ki One block satisfying <n (ki is an integer) has m rows and ki columns (i = 1, 2,...,
a) is divided into a (a is an integer) blocks that are independently driven, and in each of the a blocks, the light emitting element array includes the first electrode formed on the first wiring formed in the long side direction. While being connected, m pieces of the first wires are arranged in the short side direction, and the second electrodes are connected to the second wires formed in the short side direction, and the second wires are connected to each other. Ki leads are arranged in the long side direction, and a first lead portion for leading out the first wiring and a second lead portion for leading out the second wiring are provided.
A two-dimensional light-emitting element array, wherein a lead portion is formed in the short side direction. 3. The two-dimensional light emitting element array according to claim 2, wherein k in the light emitting element arrangement of m rows and ki columns in each block is constant. 4. The device according to claim 2, wherein the first lead portion is formed on one side in the short side direction, and the second lead portion is formed on the other side in the short side direction. The two-dimensional light-emitting element array according to claim 1. 5. The two-dimensional light emitting element array according to claim 2, wherein the first lead and the second lead are formed on the same side in the short side direction. 6. The method according to claim 1, wherein the first lead portions and the second lead portions are alternately formed on one side or the other side in the short side direction for each one or a plurality of leads. Item 3. A two-dimensional light-emitting element array according to item 2. 7. The method according to claim 1, wherein the two-dimensionally arranged light emitting elements, the first wiring, the second wiring, the first lead, and the second lead are formed on a common substrate. The two-dimensional light-emitting element array according to claim 2, wherein: 8. A third wiring portion is further formed on the short side direction side where the first lead portion exists and in the long side direction, and the number of the third wiring portions is m for each block. 3. The wiring according to claim 2, wherein each of the wirings is periodically connected in a one-to-one correspondence with the first wiring.
Dimensional light emitting element array. 9. A light-emitting element having a first electrode and a second electrode is two-dimensionally arranged in an elongated region,
A first wiring as a row wiring formed in a long side direction connected to the first electrode and a second wiring as a column wiring formed in a short side direction connected to the second electrode are formed in a matrix. In the light emitting element array connected, a first lead portion for leading out the first wiring and the second lead portion
A second lead portion for leading a wiring is formed in the short side direction, and a third wiring portion is formed on the short side direction where the first lead portion exists and in the long side direction;
The two-dimensional light-emitting element array, wherein the third wiring portion includes the same number of wires as the first wires, and is periodically connected to the first wires in a one-to-one correspondence. 10. A fourth wiring portion is further formed on the side of the short side direction where the second lead portion exists and in the long side direction, and the fourth wiring portion includes a plurality of wirings. The two-dimensional light emitting element array according to claim 2, wherein each of the plurality of wirings is periodically connected to the second lead portion. 11. A row wiring in which light emitting elements having a first electrode and a second electrode are two-dimensionally arranged in a long region, and formed in a long side direction to which the first electrode is connected. In a light emitting element array in which a first wiring as a first wiring and a second wiring as a column wiring formed in a short side direction connected to the second electrode are connected in a matrix, The first lead portion and the second lead portion
A second lead portion for leading a wiring is formed in the short side direction, and a fourth wiring portion is formed on the short side direction where the second lead portion exists, and in the long side direction,
The two-dimensional light emitting element array, wherein the fourth wiring part is divided into a plurality of parts in a long side direction, and the plurality of divided wiring parts are connected to the second lead part. 12. The two-dimensional light emitting element array according to claim 8, wherein the third wiring portion is formed to have a lower electric resistance than the first wiring. 13. The two-dimensional light emitting element array according to claim 10, wherein the fourth wiring portion is formed to have a lower electric resistance than the second wiring. 14. The two-dimensionally arranged light emitting elements,
13. The device according to claim 8, wherein the first wiring, the second wiring, the first lead, the second lead, and the third wiring are formed on a common substrate. The two-dimensional light-emitting element array according to any one of the above. 15. The two-dimensionally arranged light emitting elements,
14. The device according to claim 10, wherein the first wiring, the second wiring, the first lead, the second lead, and the fourth wiring are formed on a common substrate.
The two-dimensional light-emitting element array according to any one of the above. 16. The two-dimensionally arranged light emitting elements,
9. The device according to claim 8, wherein the first wiring, the second wiring, the first lead, and the second lead are formed on a common substrate, and the third wiring is formed on another substrate. ,
13. The two-dimensional light emitting element array according to any one of items 9 and 12. 17. The light emitting elements arranged two-dimensionally,
11. The device according to claim 10, wherein the first wiring, the second wiring, the first lead, and the second lead are formed on a common substrate, and the fourth wiring is formed on another substrate. ,
14. The two-dimensional light-emitting element array according to any one of items 11 and 13. 18. An image display device for displaying an image by driving a light source according to a video signal and scanning a light beam emitted from the light source on a display screen, wherein the light source is a light source. An image display device comprising the two-dimensional light-emitting element array according to any one of the above. 19. An image forming apparatus for driving a light source according to an image signal, irradiating a light beam emitted from the light source onto a photoconductor, and forming an image on the photoconductor, wherein the light source is An image forming apparatus comprising the two-dimensional light-emitting element array according to any one of 1 to 17.