JP2002314191A - Light emitting element array, photoelectric package, light source device and image forming device provided with them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the variation in the density when an image is formed by almost equalizing the modulation characteristics of the light emitting elements of an array of several light emitting elements which are two- dimensionally arranged. SOLUTION: A laser array 10 has several light emitting elements 14 which are arranged in grid form in the center of a base substrate 12 and are connected to several electrode pads 16 which are provided around them by wire 18. Since each piece of the wire 18 has the same length and the width, the area of the wire 18 is equal and the stray capacitance between the pieces of wire 18 is equal. In this way, the modulation characteristics of the light emitting elements 14 become almost equal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting element array in which a plurality of light-emitting elements are two-dimensionally arranged, a photoelectric package, a light source device, and an image forming apparatus having the same.

[0002]

2. Description of the Related Art In recent years, in order to cope with higher resolution and higher speed, an image forming apparatus often uses a method of simultaneously scanning a plurality of laser beams on a photosensitive member. For a light source that emits a plurality of beams, an element having a large number of light-emitting points can be manufactured at a low cost, and the light-emitting element has the advantage of low power consumption. Some use a two-dimensional light emitting element array (two-dimensional surface emitting laser array) arranged in the following manner. For example, this is described in Japanese Patent Application Laid-Open No. 5-294005.

FIG. 11 shows a schematic structure of an optical scanning device in an image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 5-294005.
Here, a plurality of laser beams emitted from a plurality of light emitting points (light emitting elements) of a semiconductor laser array 102 serving as a two-dimensional light emitting element array are collimated to a predetermined beam diameter by a collimator lens 104, and the cylindrical lens 10
6 and enters the rotary polygon mirror 108. Further, each laser beam is deflected by the rotation of the rotary polygon mirror 108, passes through the toroidal lens 110 and the scanning lens 112, forms a spot image on the surface to be scanned of the photosensitive drum 114 (spot 115), and scans the laser beam. Scan the surface. An electrostatic latent image corresponding to a change in the light intensity of the laser beam is formed on the scanning line 116. Further, a reflection mirror 118 is provided at a predetermined position in the scanning direction of the scanning surface within the deflection range of the laser beam with respect to the scanning start position, and the laser beam reflected by the reflection mirror 118 is applied to the photodetector 120. Incident on. The start of modulation of the laser beam according to the image data is controlled by a horizontal synchronization signal output from the photodetector 120 at this beam incident timing.

FIG. 12 is an enlarged plan view of a conventional two-dimensional light emitting element array (semiconductor laser array). In a laser array 130 or a two-dimensional LED or the like as shown in the figure, the same number of wirings 1 as the number of light emitting elements
36 and an electrode pad 138 are provided.

For example, when m light emitting elements are arranged in a row direction and n light emitting elements are arranged in a column direction, a cathode of each light emitting element is grounded as a common electrode, and m × n wirings are connected to an anode. . The electrode pads to which the other end of the wiring is connected are located around the light emitting element and are arranged in a line along each side of the rectangular substrate. Therefore, the respective distances (wiring paths) from the respective light emitting elements to the respective electrode pads are different, and the lengths of the respective wirings are different. In addition, the wiring of the light emitting element located near the center of the laser array is routed through the wiring connected to the peripheral light emitting element, so that the distance between the wiring and the wiring is reduced.

A stray capacitance exists in this wiring. The stray capacitance is the distance from the ground and the wiring (pattern)
(Surface area), spacing, and the bonding state of the electrode pads. Therefore, in the laser array as shown in the drawing, the stray capacitance of each wiring differs due to the difference in the length and interval of each wiring.

Further, such a laser array is packaged on a surface mount lead frame, mounted on a printed wiring board, and connected to and driven by a driving circuit IC similarly mounted on the printed wiring board. Has become.

In the example of the photoelectric package of Japanese Patent Application Laid-Open No. 10-84136 shown in FIG. 13, the electrode pad 138 on the laser array 130 and the lead frame connecting electrode pad 142 of the photoelectric package 140 are made of light-transmitting glass. The connection is made by a conductor 146 formed on 144. The lead frame is usually rectangular and each lead is arranged along each side of the frame. In the illustrated optical package 140, a light transmissive glass 144 is mounted on the lead frame, and the lead is the same as the electrode pad 142. Is located in the position. Therefore, in this example in which each electrode pad 138 of the laser array 130 and each electrode pad 142 of the light transmissive glass 144 (each lead of the lead frame) are connected by the linear conductor 146, the length of the conductor 146 is also small. Since they are different from each other, there is a difference in the stray capacitance between the conductors.

Further, also in each wiring on the printed wiring board for connecting each lead of the photoelectric package 140 and the driving circuit IC, if there is a difference in length between the wirings, a difference occurs in the stray capacitance.

Therefore, the difference between the stray capacitances of the laser array wiring, the photoelectric package wiring, and the wiring on the printed wiring board is accumulated, and in some cases, the wiring between the wirings as viewed as a whole video circuit may be accumulated. It is also conceivable that the difference in the stray capacitance at the point becomes large.

On the other hand, in an image forming apparatus using a plurality of laser beams as light sources, it is required to reduce the difference in image density between the laser beams. On the other hand, in the example of Japanese Patent Application Laid-Open No. 11-58819 shown in FIG. 14, the drive circuit of each light emitting element (laser diode) and the stray capacitance of the current path are reduced to suppress the drive current distortion and reduce the image density. Stabilization has been proposed. Specifically, the anode terminal (A1) of the laser diode (P1) is connected to the positive electrode (+) of the power supply, and the cathode terminal (K1) is connected to the negative electrode (-) of the power supply via the laser diode driving IC 148. In this method, the stray capacitance existing between the anode and the ground is always charged from the power supply. However, simply reducing the stray capacitance of the circuit corresponding to each light emitting element in this way cannot make the modulation characteristics of each light emitting element uniform.

The modulation characteristic of a laser is determined by the product of stray capacitance and impedance. Therefore, if a difference occurs in the stray capacitance between the wirings, the modulation characteristics will be different. In scanning by a laser emitted from a light source having light emitting points of m × n (m, n ≧ 2) having different modulation characteristics, for example, the rise and fall characteristics of light emission are varied, and m × n
Fluctuations in the amount of light occur in the scanning line cycle. In particular, the forward resistance of the surface-emitting laser element is about 400Ω, which is two orders of magnitude higher than the forward resistance of the edge-emitting laser of about 7Ω.

On the other hand, in an image forming apparatus using a two-dimensional light emitting element array as a light source, the number of light emitting elements corresponding to a desired resolution and printing speed is selected. Therefore, usually, a two-dimensional light-emitting element array having a different number of light-emitting elements is mounted for each model. However, in order to manufacture the apparatus at low cost, it is effective to use a common laser array and take advantage of the cost merit by increasing the number of laser arrays produced. In other words, based on the laser array of the model in which the number of light emitting elements is the largest, a part (required number) of the elements is selected in the model in which the number of light emitting elements to be used is small. Also in this case, a stray capacitance is generated in each wiring of the selected light emitting element, and if the difference becomes large, the modulation characteristics of the laser are affected.

[0014]

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide a light emitting element array in which a plurality of light emitting elements are two-dimensionally arranged, wherein each light emitting element is provided between each light emitting element and each electrode pad on the array. An object of the present invention is to obtain a light-emitting element array in which the stray capacitances generated in the wirings are made substantially the same so that the modulation characteristics of each light-emitting element are substantially constant.

Further, a second object of the present invention is to make the stray capacitance generated in each wiring between each electrode pad of the light emitting element array and each lead of the package substantially the same so that the modulation characteristics of each light emitting element can be improved. An object of the present invention is to obtain a photoelectric package which is substantially constant.

Further, a third object of the present invention is to make the stray capacitance generated in each wiring between each lead of the photoelectric package and the drive circuit of the printed wiring board substantially the same so that the modulation characteristics of each light emitting element can be improved. An object of the present invention is to obtain a light source device which is substantially constant.

A fourth object of the present invention is to provide a light emitting element array in which a part of a plurality of two-dimensionally arranged light emitting elements is selected to emit light, the light emitting elements each having a substantially constant modulation characteristic. Consists in obtaining an array.

[0018]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of light emitting elements arranged on a base substrate and the base substrate is provided between the plurality of light emitting elements. In a light-emitting element array including a plurality of electrode pads individually connected by a plurality of wirings provided thereon, the floating capacitances of the plurality of wirings are substantially the same.

According to the first aspect of the present invention, a plurality of light emitting elements are provided on the base substrate and are arranged two-dimensionally, and a plurality of wirings are provided between the plurality of electrode pads on the base substrate. Connected individually. By making the stray capacitances of the plurality of wirings substantially the same, the modulation characteristics of each light emitting element become substantially constant.

Further, in the plurality of wirings in the light emitting element array according to the first aspect, the area may be substantially the same as in the second aspect, and the length and the width may be substantially the same as in the third aspect. Good. Furthermore, the plurality of electrode pads in the light emitting element array according to any one of claims 1 to 3 may be arranged in a row as in claim 4.

According to a fifth aspect of the present invention, a plurality of light emitting elements arranged in a lattice on a base substrate and a plurality of wirings provided on the base substrate separate the plurality of light emitting elements. A plurality of electrode pads connected to
In a light-emitting element array in which a part of the plurality of light-emitting elements is selected and emits light, the light-emitting elements are arranged at positions that are line-symmetric with respect to a center line passing through the centers of the plurality of light-emitting elements arranged in a lattice pattern. Is selected to emit light.

According to the fifth aspect of the present invention, the plurality of light emitting elements are provided on the base substrate and are arranged two-dimensionally and in a lattice, and the plurality of light emitting elements are provided on the base substrate between the plurality of electrode pads. Individually connected by wiring. Then, a light emitting element arranged at a position symmetrical with respect to a center line passing through the centers of the plurality of light emitting elements arranged in a lattice is selected to emit light. Thereby, the pattern of each wiring connected to each light emitting element forms a symmetrical shape with respect to the center line, and the fluctuation of the stray capacitance in the circuit is suppressed.

According to a sixth aspect of the present invention, there are provided a plurality of two-dimensionally arranged light emitting elements provided on a package substrate and a plurality of electrode pads individually connected to the plural light emitting elements. In a photoelectric package, comprising: a light emitting element array; and a plurality of electrode terminals connected between the plurality of electrode pads by a plurality of wires provided on the package substrate. It is characterized in that the capacities are substantially the same.

According to the present invention, a light emitting element array having a plurality of two-dimensionally arranged light emitting elements and a plurality of electrode pads individually connected to the plurality of light emitting elements is provided on a package substrate. And a plurality of electrode pads and a plurality of electrode terminals are individually connected by a plurality of wirings provided on the package substrate. By making the stray capacitances of the plurality of wirings substantially the same, the modulation characteristics of each light emitting element become substantially constant.

The plurality of wirings in the photoelectric package according to the sixth aspect may have substantially the same area as in the seventh aspect, and may have substantially the same length and width as in the eighth aspect. . Further, the plurality of electrode terminals in the photoelectric package according to any one of claims 6 to 8 may be arranged in a row as in claim 9.

According to a tenth aspect of the present invention, there is provided a light emitting element array provided on a substrate, wherein a plurality of light emitting elements are two-dimensionally arranged, and a plurality of leads individually connected to the plurality of light emitting elements. A light source device, comprising: a photoelectric package having a plurality of leads; and a drive circuit that drives the light emitting element array by individually connecting the plurality of leads with a plurality of wirings provided on the substrate. This is characterized in that the stray capacitance generated in the wiring is substantially the same.

According to the tenth aspect of the present invention, there is provided a light emitting element array having a plurality of light emitting elements arranged two-dimensionally and a photoelectric package having a plurality of leads individually connected between the plurality of light emitting elements; A drive circuit for driving the element array is provided on the substrate, and the leads and the drive circuit are individually connected by a plurality of wirings provided on the package substrate. By making the stray capacitances of the plurality of wirings substantially the same, the modulation characteristics of each light emitting element become substantially constant.

According to an eleventh aspect of the present invention, the light emitting element array in which a plurality of light emitting elements are two-dimensionally arranged, and the plurality of light emitting elements are connected by individual wirings to drive the light emitting element array A stray capacitance generated in the plurality of wirings is made substantially the same.

According to the eleventh aspect of the present invention, a light emitting element array in which a plurality of light emitting elements are two-dimensionally arranged and a driving circuit for driving the light emitting element array are connected by individual wiring, and the plurality of light emitting elements are connected to each other. By making the stray capacitances of the wiring substantially the same, the modulation characteristics of each light emitting element become substantially constant.

In the light source device according to the tenth or eleventh aspect, the plurality of wirings may have substantially the same area as in the twelfth aspect, and may have substantially the same length and width as in the thirteenth aspect. It may be.

The invention according to claim 14 is the first invention.
The light-emitting element array according to any one of claims 1 to 5, and / or the photoelectric package according to any one of claims 6 to 9, and / or any one of claims 10 to 13. The invention is applied to an image forming apparatus that includes a light source device and forms an image on a photoreceptor by a light beam emitted from a light emitting element array, and thereby suppresses density fluctuation in image formation using a plurality of laser beams as a light source. You.

[0032]

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

[First Embodiment] FIG. 1 shows a two-dimensional light-emitting element array according to a first embodiment of the present invention. As shown in the drawing, a laser array (two-dimensional light-emitting element array) 10 has a base substrate 12 having a square shape, and a plurality of light-emitting elements 14 are arranged in a lattice shape in a central portion on the base substrate 12 as in the related art. . Around the light emitting element 14, the same number of electrode pads 16 as the light emitting element 14 are provided.
The corresponding light emitting element 14 is connected to the anode by a wiring 18. Further, the cathode of each light emitting element 14 is grounded as a common electrode as in the related art.

Each wiring 18 is formed on the base substrate 12 by metal deposition, and has a width of 5 μm and a length of about 500 μm.
And the number of bent portions in the length direction is three or less. Further, the electrode pads 16 arranged along each side of the base substrate 12 are arranged such that adjacent electrode pads are substantially alternated as shown in the figure. This is because the length of the wiring 18 is set as short as possible.

Here, the stray capacitance C generated between the wiring and the ground is obtained by C = εS / d, where ε is the dielectric constant of the dielectric, S is the area of the wiring, and d is the distance from the ground. .

In the laser array 10 of the present embodiment, the distance from the ground is constant for each wiring 18, and the width and length of each wiring 18 are equalized and the area is equalized. The stray capacitances are equal.

As described above, the modulation characteristics of the laser,
That is, the time constant is determined by the product of the stray capacitance and the impedance, and when the shape of the wiring changes, the impedance changes. However, the impedance of the surface emitting laser element is about 400Ω, which is four orders of magnitude larger than the impedance of the wiring, so that the change in the impedance of the wiring can be ignored here.

As a result, the modulation characteristics of each light emitting element 14 are substantially constant, and the density fluctuation of the image forming apparatus using the laser array 10 as a light source is suppressed.

The stray capacitance generated between the wiring and the adjacent wiring is generally smaller than the stray capacitance generated between the wiring and the ground. However, when the stray capacitance needs to be considered, it can be dealt with by adjusting the wiring interval or changing the arrangement of the electrode pads.

[Second Embodiment] Next, a second embodiment of the present invention will be described. FIG. 2 shows a two-dimensional light emitting element array according to a second embodiment of the present invention.

In the laser array 20 of this embodiment, as in the first embodiment, a plurality of light emitting elements 14 are
And a plurality of electrode pads 16 provided around the light emitting element 14 are connected by a plurality of wirings 22 having the same length and width. Therefore, the stray capacitance of each wiring 22 is made equal. However, the electrode pad 16 here is the base substrate 1
2 are arranged in a line along each side, and accordingly, each wiring 22 is made longer than the wiring 18 of the first embodiment,
As shown, a number of bent portions in the length direction are formed.

Accordingly, when the laser array 20 is mounted on the package substrate, the bonding workability for connecting the electrode pads of the package substrate and the electrode pads 16 of the laser array 20 is maintained at the same level as before. As described above, even in the configuration in which the electrode pads 16 are arranged in a row, it is possible to arrange the wirings 22 with the same length and width.

[Third Embodiment] Next, a third embodiment of the present invention will be described. FIG. 3 shows a photoelectric package according to a third embodiment of the present invention.

As shown in the figure, in the photoelectric package 30, a laser array 20 is mounted at the center of a package substrate 32, and the same number of leads 34 as the electrode pads 16 of the laser array 20 are provided around the laser array 20. I have.
The leads 34 and the corresponding electrode pads 16 are connected by conductors 36 formed on the package substrate 32 by metal evaporation.

Each of the conductors 36 has a width of 30 μm.
m and the length are set to about 10 mm, and are formed in a straight line as shown in the figure. Accordingly, each lead 34
Are arranged on substantially the same circumference.

Thus, the stray capacitance of each conductor 36 is made equal. Further, as described in the second embodiment, since the stray capacitance of each wiring 22 of the laser array 20 is also equal, the modulation characteristic of each light emitting element 14 is substantially constant,
Density fluctuation of the image forming apparatus using the photoelectric package 30 as a light source is suppressed.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. FIG. 4 shows an optoelectronic package according to a fourth embodiment of the present invention.

The photoelectric package 40 of the present embodiment also has a third
As in the embodiment, the laser array 20 is provided at the center of the package substrate 32, and a plurality of leads 34 provided around the laser array 20 are provided with a plurality of leads 34 having the same length and width. They are connected by a conductor 42. Therefore, the stray capacitance of each conductor 42 is made equal. However, the leads 34 here are connected to the package substrate 3
2, the conductors 42 are longer than the conductors 36 of the third embodiment, and a bent portion is formed in the length direction as shown in the drawing. Some are.

As a result, a general-purpose lead frame can be applied to the lead frame on which the photoelectric package 40 is mounted. In this manner, even when the leads 34 are arranged in a row, the length of each conductor 36 can be reduced. In addition, it is possible to carry out wiring with uniform width dimensions.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described. FIG. 5 shows a photoelectric package according to a fifth embodiment of the present invention.

The photoelectric package 50 of the present embodiment also has
As in the embodiment, the laser array 20 is provided at the center of the package substrate 32, and the leads 34 are
2 are arranged in a line along each side. However, the length and width of each linear conductor connected to each electrode pad 16 and each lead 34 of the laser array 20 are individually set so that the area (surface area of the pattern) is the same.

Here, the conductor 52 connected to the lead 34A located near the center of each side of the package substrate 32 and having the shortest linear distance to the corresponding electrode pad 16 is provided.
A is wider as its length is reduced.
Conversely, the conductor 52D connected to the lead 34D located near each side edge of the package substrate 32 and having the longest linear distance with the corresponding electrode pad 16 is the conductor 52A.
The width is narrowed according to the length dimension so as to be the same as the area of. The widths of the conductors 52B and 52C disposed between the conductors 52A and 52D are set according to the lengths of the conductors 52A and 52D so that they have the same area as the conductors 52A and 52D. . Therefore, the stray capacitances of the conductors 52A, 52B, 52C, and 52D are equal, and the modulation characteristics of each light emitting element 14 are substantially constant.

As described above, the difference in the stray capacitance of each conductor 52 can be suppressed even if the length and width are arbitrarily changed under the condition that the area of the conductor is the same.

The above-described configuration in which the length and width are set so that the area of each conductor is equal to eliminate the difference in stray capacitance between the conductors is the same as that of the laser array of the first and second embodiments. Can also be applied to the wiring in.

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described. FIGS. 6 to 8 show a driver substrate of a light source device according to a sixth embodiment of the present invention.

As shown, on the driver board (printed circuit board) 62 of the light source device 60, the photoelectric package 30 described in the third embodiment and a drive circuit (IC) 64 for driving the photoelectric package 30 are provided. It is mounted, and each of the leads 34 of the photoelectric package 30 and the drive circuit 64 are connected by a printed wiring formed on a driver board 62.

In the example of FIG. 7, the lengths and widths of the printed wirings 66 connected to the leads 34 are uniform.
Further, in the example of FIG. 8, the length and the width are set so that the areas of the printed wirings 66A to 66I are the same.

Thus, in each case, the stray capacitances of the printed wiring are equalized and the photoelectric package 3
The modulation characteristic of each light emitting element of 0 is substantially constant, and therefore, the density fluctuation of the image forming apparatus equipped with the light source device 60 is suppressed.

In the first to sixth embodiments, the stray capacitance generated between each wiring, conductor, and printed wiring is equal for each unit such as the laser array, the photoelectric package, and the driver board of the light source device. This is an example. However, the present invention is not limited to those embodiments, and the entire conduction path (wiring +
It is also possible to set the lengths and widths of individual wirings, conductors, and printed wirings so that the stray capacitances between the conductive paths are equal in (conductors + printed wirings).

[Seventh Embodiment] Next, a seventh embodiment of the present invention will be described. In the present embodiment, in order to reduce the manufacturing cost of the image forming apparatus, a model in which a two-dimensional light-emitting element array having a necessary number or more light-emitting elements is used, and a part (necessary number) of the light-emitting elements is selected to emit light. Is about.

FIG. 9 shows a two-dimensional light emitting element array according to a seventh embodiment of the present invention. The laser array 70 is provided with a total of 36 light emitting elements 14 arranged in a lattice pattern, six in the row direction and in the column direction. In the image forming apparatus on which the laser array 70 is mounted, eight of the light emitting elements 14 are used.

The light-emitting elements 14 used are arranged at positions that are line-symmetric with respect to the center line L in the horizontal direction passing through the center C of the arranged light-emitting element group.
14D and the light emitting elements 14E to 14H are selected.
Note that this center line L is the same even if it extends in the vertical direction in the figure.

Therefore, the pattern of the wiring 72C of the light emitting element 14C and the wiring 72G of the light emitting element 14G are symmetrical with respect to the center line L, and the wiring 72D of the light emitting element 14D and the wiring of the light emitting element 14H are similarly formed. The pattern of 72H is symmetrical with respect to the center line L. Although not shown, the wirings of the light emitting elements 14A and 14E and the wirings of the light emitting elements 14B and 14F also have symmetrical patterns with the center line L interposed therebetween. As a result, the fluctuation of the stray capacitance between the circuits is suppressed, and the density fluctuation during image formation is suppressed.

In this embodiment, the light-emitting elements to be used are selected from the vicinity of the center of the laser array 70. However, the light-emitting elements 14A to 14F are routed between the light-emitting elements located in the periphery and their wirings. For the sake of convenience, the distance from other wiring is reduced. Therefore, the stray capacitance generated between adjacent wirings is likely to increase. However, even in such a case, by adopting the above-described configuration, the effect of suppressing the fluctuation of the stray capacitance can be enhanced.

Finally, the amount of exposure when a laser array having a plurality of light emitting points is used as a light source of an image forming apparatus as shown in FIG. 11 will be described. FIG. 10 shows the relationship between the response characteristics of the laser drive and the distribution of the amount of exposure to it.

When the video signal shown in FIG. 10A is supplied from the driver circuit IC to the laser array, the signal passing through the wiring having a small stray capacitance has the waveform shown by A1 in FIG. 10B flowing to the light emitting element. On the other hand, a signal having a slow response characteristic flows through the element as shown by B1 in FIG. When the element emitting light at this timing is scanned by a rotating polygon mirror and exposed to the photosensitive drum, each of the elements shown in FIG.
The exposure distribution shown in A2 and B2 of 0 (C) is obtained.
As described above, when the response characteristics are different for each element, a density variation occurs at a scanning line cycle corresponding to the number of light emitting points.

However, by using the laser array, the photoelectric package, and the light source device described in the first to seventh embodiments, the stray capacitance generated in the wiring of each light emitting element is equalized. The response characteristics are uniform, and the density fluctuation of the printed image is suppressed.

[0068]

According to the light emitting element array, the photoelectric package and the light source device of the present invention, the modulation characteristics of each light emitting element are substantially constant. Further, in an image forming apparatus provided with these, fluctuations in the density of a printed image are suppressed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of a laser array according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a schematic configuration of a laser array according to a second embodiment of the present invention.

FIG. 3 is a plan view showing a schematic configuration of a photoelectric package according to a third embodiment of the present invention.

FIG. 4 is a plan view showing a schematic configuration of a photoelectric package according to a fourth embodiment of the present invention.

FIG. 5 is a plan view showing a schematic configuration of a photoelectric package according to a fifth embodiment of the present invention.

FIG. 6 is a perspective view showing a schematic configuration of a driver board according to a sixth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram illustrating an example of a printed wiring as viewed in plan for a driver board according to a sixth embodiment of the present invention.

FIG. 8 is a schematic configuration diagram illustrating another example of a printed wiring as viewed in plan from a driver board according to a sixth embodiment of the present invention.

FIG. 9 is a plan view showing a schematic configuration of a main part of a laser array according to a seventh embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a laser response characteristic and an exposure amount distribution with respect to the response characteristic.

FIG. 11 is a schematic configuration diagram of a light source device in a conventional image forming apparatus.

FIG. 12 is a plan view showing a schematic configuration of a conventional laser array.

FIG. 13 is a plan view showing a schematic configuration of a conventional photoelectric package.

FIG. 14 is an electric circuit diagram of a conventional laser array.

[Explanation of symbols]

 Reference Signs List 10 laser array (light emitting element array) 12 base substrate 14 light emitting element 14A to 14F light emitting element 16 electrode pad 18 wiring 20 laser array (light emitting element array) 22 wiring 30 photoelectric package 32 package substrate 34 lead (electrode terminal) 34A to 34D lead (Electrode terminal) 36 Conductor (wiring) 40 Photoelectric package 42 Conductor (wiring) 50 Photoelectric package 52 Conductor (wiring) 52A to 52D Conductor 60 Light source device 62 Driver board (substrate) 64 Drive circuit 66 Printed wiring (wiring) 66A-66I Printed wiring (wiring) 70 Laser array 72C, 72D, 72G, 72H Wiring

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C362 AA07 AA13 AA15 AA17 2H045 AA01 BA23 BA33 CB42 5F073 AB04 AB16 AB21 AB27 AB29 BA07 FA15 FA18 FA28

Claims (14)

[Claims] A plurality of light emitting elements arranged on a base substrate; a plurality of electrode pads individually connected to the plurality of light emitting elements by a plurality of wirings provided on the base substrate; 2. The light emitting element array according to claim 1, wherein the plurality of wirings have substantially the same stray capacitance. 2. The light emitting element array according to claim 1, wherein said plurality of wirings have substantially the same area. 3. The light emitting element array according to claim 1, wherein the plurality of wirings have substantially the same length and width. 4. The apparatus according to claim 1, wherein said plurality of electrode pads are arranged in a row.
Item 12. A light-emitting element array according to Item 1. 5. A plurality of light-emitting elements arranged in a lattice on a base substrate, and a plurality of electrodes individually connected to the plurality of light-emitting elements by a plurality of wirings provided on the base substrate. And a pad, wherein a part of the plurality of light emitting elements is selected and emits light, wherein the position is line-symmetric with respect to a center line passing through the center of the plurality of light emitting elements arranged in a lattice pattern. A light emitting element array, wherein the light emitting element arranged in the light emitting element is selected to emit light. 6. A light emitting element array provided on a package substrate and having a plurality of two-dimensionally arranged light emitting elements and a plurality of electrode pads individually connected to the plurality of light emitting elements; And a plurality of electrode terminals individually connected to a plurality of electrode pads by a plurality of wirings provided on the package substrate, wherein the stray capacitances of the plurality of wirings are substantially the same. A photoelectric package. 7. The photoelectric package according to claim 6, wherein the plurality of wirings have substantially the same area. 8. The photoelectric package according to claim 6, wherein the plurality of wirings have substantially the same length and width. 9. The photoelectric package according to claim 6, wherein the plurality of electrode terminals are arranged in a row. 10. A photoelectric package provided on a substrate, comprising a light emitting element array in which a plurality of light emitting elements are two-dimensionally arranged, and a plurality of leads individually connected to the plurality of light emitting elements; A driving circuit for driving the light emitting element array by being individually connected to a plurality of leads by a plurality of wirings provided on the substrate; and a stray capacitance generated in the plurality of wirings. A light source device characterized by being substantially the same. 11. A light-emitting element array in which a plurality of light-emitting elements are two-dimensionally arranged, and a driving circuit connected to the plurality of light-emitting elements by individual wiring to drive the light-emitting element array. In the light source device, the stray capacitance generated in the plurality of wirings is substantially the same. 12. The light source device according to claim 10, wherein the plurality of wirings have substantially the same area. 13. The light source device according to claim 10, wherein the plurality of wirings have substantially the same length and width. 14. The light-emitting element array according to claim 1, and / or the photoelectric package according to claim 6, and / or 10 to 10. An image forming apparatus, comprising: the light source device according to any one of claims 13 to 13, wherein an image is formed on a photosensitive member by a light beam emitted from a light emitting element array.