JP2019111731A - Optical element unit, print head, reading head, image forming device, and image reading device - Google Patents

Abstract

To provide an optical element unit which suppresses inclination of an optical element chip and can reduce an occupied area of a wiring layer on a substrate, and provide a print head, a reading head, an image forming device, and an image reading device.SOLUTION: An optical element unit 1 includes a substrate 11, a wiring layer 12 formed on the substrate 11, and an insulating layer 13 which covers the wiring layer 12, and an optical element chip 3 fixed to the insulating layer 13. The wiring layer 12 includes a connection part 20 which extends in a first direction on a surface of the substrate 11, and a plurality of extension parts 21 which extend in a second direction substantially orthogonal to the first direction from the connection part 20 and are arrayed in the first direction. The optical element chip 3 is arranged in a region of the wiring layer 12 where the plurality of extension parts 21 are arrayed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical element unit provided with an optical element, a print head, a reading head, an image forming apparatus, and an image reading apparatus.

  The print head of the image forming apparatus uses a light emitting unit (optical element unit) in which an LED array chip (optical element chip) is mounted on a printed wiring board. The printed wiring board is obtained by forming a wiring layer on the substrate and covering the wiring layer with an insulating layer. The LED array chip is fixed to the surface of the insulating layer by adhesion (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2000-301762 (see FIG. 1)

  Here, since the surface of the insulating layer covering the wiring layer is inclined in the vicinity of the end portion of the wiring layer, the LED array chip may be inclined when the LED array chip is fixed to this inclined region. Therefore, it is necessary to secure a certain distance between the end of the wiring layer and the arrangement area of the LED array chip. Further, since it is necessary to form connection pads or patterns in addition to the wiring layer on the substrate, it is required to reduce the area occupied by the wiring layer on the substrate.

  The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to suppress an inclination of an optical element chip and to reduce an occupied area of a wiring layer on a substrate.

  The optical element unit of the present invention includes a substrate, a wiring layer formed on the substrate, an insulating layer covering the wiring layer, and an optical element chip having an optical element and fixed to the insulating layer. The wiring layer includes a connecting portion extending in a first direction on the surface of the substrate, and a plurality of extending in a second direction substantially orthogonal to the first direction from the connecting portion and arranged in the first direction. And an extending portion. The optical element chip is disposed in a region in which a plurality of extending portions of the wiring layer are arranged.

  A print head according to the present invention comprises the above optical element unit and a lens unit for focusing light emitted from the optical element on a target surface, and the optical element is a light emitting element. An image forming apparatus according to the present invention includes the above-described print head.

  The reading head according to the present invention comprises the above optical element unit and a lens unit for focusing light from a document on the optical element, and the optical element is a light receiving element. An image reading apparatus according to the present invention includes the above-described reading head.

  According to the present invention, since the wiring layer is configured to have a plurality of extending portions, a part of the insulating layer covering the wiring layer enters the gap between the adjacent extending portions, and the insulating layer on the wiring layer Thickness becomes thinner. Therefore, the sloped area of the surface of the insulating layer can be narrowed. Thereby, the distance between the end of the wiring layer and the arrangement area of the optical element chip can be shortened. As a result, the inclination of the optical element chip can be suppressed, and the area occupied by the wiring layer on the substrate can be reduced.

It is a top view which shows the light emission part unit (optical element unit) of 1st Embodiment. It is a top view which shows the insulating substrate and wiring layer of the light emission part unit of 1st Embodiment. It is sectional drawing of the arrow direction in line segment III-III of FIG. It is sectional drawing of the arrow direction in line segment IV-IV of FIG. It is sectional drawing of the arrow direction in line segment VV of FIG. It is a figure which expands and shows the wiring layer of 1st Embodiment, an insulating layer, and an adhesive agent. It is a top view which shows the light emission part unit of a comparative example. It is a top view which shows the insulating substrate and wiring layer of a light emission part unit of a comparative example. It is sectional drawing of the arrow direction in line segment IX-IX of FIG. It is sectional drawing of the arrow direction in line segment XX of FIG. It is a top view which shows the light emission part unit of 2nd Embodiment. It is a top view which shows the insulating substrate and wiring layer of the light emission part unit of 2nd Embodiment. It is sectional drawing of the arrow direction in line segment XIII-XIII of FIG. It is a sectional view showing a print head which has an optical element unit of each embodiment. It is a figure which shows the image forming apparatus provided with the print head of FIG. FIG. 2 is a partial cross-sectional perspective view showing a read head having an optical element unit of each embodiment. It is a figure which shows the image reader provided with the read head of FIG.

First Embodiment
<Configuration of Optical Element Unit>
FIG. 1 is a plan view showing a light emitting unit 1 as an optical element unit according to the first embodiment. The light emitting unit 1 includes a printed wiring board 10 and a plurality of light emitting devices 3 mounted on the printed wiring board 10.

  The printed wiring board 10 has an insulating substrate 11 as a substrate, a wiring layer 12 formed on the surface of the insulating substrate 11, and an insulating layer 13 covering the surface of the wiring layer 12. The insulating substrate 11 is an insulating substrate made of, for example, glass epoxy.

  The wiring layer 12 is made of, for example, a copper foil. It is desirable to perform a gold plating process on the surface of the wiring layer 12 in order to prevent oxidation and improve wire bondability.

  The insulating layer 13 is made of, for example, a solder resist. The solder resist contains, for example, an epoxy resin as a main component. The insulating layer 13 stabilizes the attitude (orientation) of the light emitting device 3. The insulating layer 13 also reduces the manufacturing cost of the printed wiring board 10 by reducing the plating area.

  The printed wiring board 10 has an elongated shape that is long in one direction (horizontal direction in the drawing). Hereinafter, the longitudinal direction of the printed wiring board 10 is taken as an X direction. A direction orthogonal to the X direction in a plane parallel to the surface of the printed wiring board 10 (more specifically, the surface of the insulating substrate 11) is taken as a Y direction. A direction orthogonal to both the X direction and the Y direction is taken as the Z direction.

  A plurality of light emitting devices 3 are fixed to the surface of the insulating layer 13 of the printed wiring board 10 by an adhesive 14 (FIG. 3). The adhesive 14 is, for example, an insulating die bonding paste. The plurality of light emitting devices 3 are arranged in a line in the X direction. A constant gap C is formed between the light emitting devices 3 adjacent in the X direction.

  The light emitting device 3 is an LED array chip here. The light emitting device 3 includes an elongated substrate 30 long in the X direction, and a plurality of LEDs (light emitting diodes) 31 as light emitting elements (optical elements) joined to the surface of the substrate 30.

  The substrate 30 is made of, for example, a semiconductor substrate such as Si, GaAs, GaP, InP, GaN or ZnO. The LED 31 is obtained, for example, by bonding an epitaxial layer grown on another substrate (growth substrate) to the surface of the substrate 30. In addition, you may use another light emitting element (for example, light emitting thyristor) instead of LED. Bonding pads (not shown) for supplying signals and the like to the LEDs 31 are formed on the surface of the substrate 30, and are connected to the outside by bonding wires.

  The LEDs 31 are arranged on the surface of the substrate 30 in a line at equal intervals in the X direction. The arrangement pitch of the LEDs 31 (that is, the distance between the centers of the adjacent LEDs 31) is 21 μm when the resolution is 1200 dpi, and 42 μm when the resolution is 600 dpi.

  Connection pads 18 a, 18 b and 18 c are formed in the area 17 where the wiring layer 12 is not formed on the insulating substrate 11. The connection pad 18 a supplies the ground potential (GND) to the light emitting device 3. The connection pads 18 b and 18 c supply power to the light emitting device 3 and are connected by the pattern unit 19 as needed. The insulating layer 13 has openings at positions corresponding to the connection pads 18a, 18b and 18c, and exposes the connection pads 18a, 18b and 18c.

  Further, in the region 17 of the insulating substrate 11, although not shown, a pattern and a connection pad for supplying a signal or the like to the light emitting device 3 are also formed.

  Although the wiring layer 12 is covered with the insulating layer 13, in FIG. 1, the outline of the wiring layer 12 is indicated by a solid line in order to easily show the shape of the wiring layer 12. The wiring layer 12 is hatched in a dotted manner. The same applies to FIGS. 7 and 11 described later.

  FIG. 2 is a plan view showing the insulating substrate 11 and the wiring layer 12 of the printed wiring board 10. The wiring layer 12 has a comb shape as a whole. Specifically, the wiring layer 12 has a connecting portion 20 extending in the X direction and a plurality of comb-tooth portions 21 as extending portions extending from the connecting portion 20 in the Y direction. Grooves 22 are formed between adjacent comb teeth 21.

  The connecting portion 20 is formed on one side (here, the + Y side) with respect to the center of the insulating substrate 11 in the Y direction (width direction). The comb teeth 21 are formed in the central region of the insulating substrate 11 in the Y direction. In other words, the comb-tooth portion 21 is formed in the arrangement region of the light emitting device 3 in the insulating substrate 11.

  Each of the comb teeth 21 has a constant width W. Further, the comb teeth 21 are arranged in the X direction with a predetermined gap G therebetween. It is desirable that the distance G between the comb teeth 21 (that is, the gap between the adjacent comb teeth 21) be wider than the width W of the comb teeth 21 (i.e., G> W). Here, the width W of the comb teeth 21 is, for example, 0.1 mm. The distance G between adjacent comb teeth 21 is, for example, 0.125 mm.

  The length in the Y direction of the comb teeth 21 is the width of the light emitting device 3 in the Y direction, twice the mounting accuracy (for example, 0.1 mm) of the light emitting device 3, and the Y direction of the insulating layer inclined region A1 described later. It is set to the sum of length and more. The end (end in the −Y direction) of the comb tooth 21 opposite to the connection 20 is referred to as a wiring end 25.

  The wiring layer 12 has openings 23 at positions opposed to both ends of the light emitting device 3 (FIG. 1) in the Y direction. The insulating layer 13 (FIG. 1) covers almost the entire surface of the insulating substrate 11, but has an opening 13b at a position corresponding to the opening 23. The inner side of the openings 23 and 13b is an opening area 16 (FIG. 1) where the insulating substrate 11 is exposed. The opening region 16 is provided to prevent the adhesive for fixing the light emitting device 3 from crawling in the gap G (FIG. 1) of the adjacent light emitting devices 3 by capillary action.

  FIG. 3 is a cross-sectional view in the arrow direction along line segment III-III shown in FIG. 1, that is, a cross-sectional view in a plane passing through the comb-tooth portion 21 of the wiring layer 12. FIG. 4 is a cross-sectional view in the arrow direction along line segment IV-IV shown in FIG. 1, that is, a cross-sectional view in a plane passing through the groove 22 of the wiring layer 12. FIG. 5 is a cross-sectional view in the arrow direction along line segment V-V shown in FIG. 1, that is, a cross-sectional view in a plane across the comb teeth 21 of the wiring layer 12.

  As described above, the wiring layer 12 is covered with the insulating layer 13. As shown in FIG. 3, the insulating layer 13 is filled between the comb teeth 21 and the light emitting device 3. Further, as shown in FIG. 4, the insulating layer 13 is filled between the insulating substrate 11 and the light emitting device 3 in a portion without the comb teeth 21, that is, in the groove 22.

  That is, as shown in FIG. 5, the comb teeth 21 are arranged at equal intervals in the X direction on the lower side of the light emitting device 3 (that is, on the insulating substrate 11 side). A part of the insulating layer 13 covers the comb teeth 21, and another part of the insulating layer 13 is filled in the groove 22.

  Further, as shown in FIG. 3, the height of the surface of the insulating layer 13 is substantially constant on the comb teeth 21, but lower than the tip of the comb teeth 21 (that is, the wiring end 25). . Therefore, the surface of the insulating layer 13 is inclined in the area A1 in the vicinity of the wiring end 25 in the Y direction. Hereinafter, a region where the surface of the insulating layer 13 is inclined is referred to as an insulating layer inclined region A1. The length in the Y direction of the insulating layer inclined region A1 depends on the thickness of the insulating layer 13 on the comb-tooth portion 21.

  FIG. 6 is a cross-sectional view showing the wiring layer 12, the insulating layer 13 and the adhesive 14 on the insulating substrate 11 in an enlarged manner. The height T1 from the surface of the insulating substrate 11 to the surface of the comb teeth 21 is preferably about 30 to 40 μm. The surface of the insulating layer 13 is slightly higher in the portion covering the comb-tooth portion 21 and slightly lower in the portion filled in the groove 22. The height T2 from the surface of the insulating substrate 11 to the highest portion of the insulating layer 13 is preferably about 40 to 55 μm. The difference (T2-T1) between the heights T1 and T2 is preferably about 10 to 15 μm.

<Mounting process of light emitting unit 1>
The process of mounting the light emitting unit 1 on the printed wiring board 10 is as follows. First, the wiring layer 12, the connection pads 18a to 18c, the pattern portion 19 and the like are formed on the surface of the insulating substrate 11. The insulating layer 13 is formed of solder resist so as to cover the surface of the printed wiring board 10 using, for example, screen printing. At this time, the openings 23 and the openings on the connection pads 18 a, 18 b and 18 c are formed in the insulating layer 13.

  Of the solder resist supplied onto the insulating substrate 11, part of the solder resist supplied to the arrangement region of the light emitting device 3 (that is, the region in which the comb teeth 21 and the groove 22 are arranged) Be filled. Therefore, the thickness of the insulating layer 13 on the comb-tooth portion 21 becomes thinner as compared to the case where the wiring layer 12 is formed as a solid pattern. By reducing the thickness of the insulating layer 13 on the comb-tooth portion 21, the length of the insulating layer inclined region A1 (FIG. 3) in the Y direction becomes short.

  The adhesive 14 which is a die bonding paste is applied to the surface of the insulating layer 13 thus formed. The application range of the adhesive 14 is a region where the comb teeth 21 and the groove 22 of the wiring layer 12 are aligned, and is a region on the + Y side of the insulating layer inclined region A1. The application of the adhesive 14 is performed, for example, by attaching a die bonding paste to a rod-like application member and applying a brush on the surface of the insulating layer 13 with the application member.

  After the adhesive 14 is applied to the surface of the insulating layer 13 in this manner, the light emitting device 3 is pressed against the adhesive 14. Thereby, the light emitting device 3 is fixed to the surface of the insulating layer 13 via the adhesive 14. The light emitting device 3 is supported by a plurality of comb teeth 21 arranged in the X direction. Further, since the light emitting device 3 is fixed at a position avoiding the insulating layer inclined region A1, the inclination of the light emitting device 3 is suppressed.

<Function>
Next, the operation of the light emitting unit 1 according to the first embodiment will be described. First, a light emitting unit unit 1B of a comparative example to the light emitting unit unit 1 of the first embodiment will be described. FIG. 7 is a plan view showing the light emitting unit 1B. The light emitting unit 1B includes a printed wiring board 10B and a plurality of light emitting devices 3 bonded to the surface of the printed wiring board 10B. The printed wiring board 10B differs from the wiring layer 12 of the first embodiment in the shape of the wiring layer 12B. The light emitting device 3 is the same as that of the first embodiment.

  FIG. 8 is a plan view showing the insulating substrate 11 and the wiring layer 12B of the printed wiring board 10B of the comparative example. The wiring layer 12B does not have the comb-tooth portion 21 like the wiring layer 12 (FIG. 2) of the first embodiment. That is, the wiring layer 12B is formed as a solid pattern except for the openings 23 at both ends of the light emitting device 3 in the X direction.

  FIG. 9 is a cross-sectional view in the arrow direction of line segment IX-IX in FIG. 7. FIG. 10 is a cross-sectional view in the arrow direction of line segment XX in FIG. 7. As shown in FIG. 9, the height t from the surface of the wiring layer 12B to the surface of the insulating layer 13 is about 20 μm.

  Also in this comparative example, the height of the surface of the insulating layer 13 is lower outside the end of the wiring layer 12 (that is, the wiring end 25). Therefore, the surface of the insulating layer 13 is inclined in the region A2 near the wiring end 25 in the Y direction. The length in the Y direction of the insulating layer inclined region A2 depends on the thickness t (about 20 μm in this case) of the insulating layer 13 covering the wiring layer 12B. In this comparative example, the length in the Y direction of the insulating layer inclined region A2 is about 0.2 mm.

  When the light emitting device 3 is bonded to the insulating layer inclined region A2, the light emitting device 3 is inclined, and as a result, the emission direction of the light from the LED 31 may be inclined with respect to the Z direction. Therefore, in the printed wiring board 10B of the comparative example, a distance of at least the insulating layer inclined area A2 (for example, about 0.2 mm or more) is provided between the arrangement area of the light emitting device 3 and the wiring end 25.

  On the other hand, in the area 17 where the wiring layer 12B is not formed in the insulating substrate 11, in addition to the connection pads 18a to 18c described above, patterns and pads not shown are formed. However, since it is necessary to secure a distance equal to or greater than the insulating layer inclined region A2 from the arrangement region of the light emitting device 3 to the wiring end 25, the occupied area of the wiring layer 12B is increased. Therefore, it is difficult to widen the region 17 for forming the pattern and the pad on the insulating substrate 11.

  On the other hand, in the light emitting unit 1 according to the first embodiment, as shown in FIG. 5, the wiring layer 12 is configured to have a plurality of comb teeth 21, so a part of the insulating layer 13 is The groove 22 is filled, and the thickness (T2-T1) of the insulating layer 13 on the comb-tooth portion 21 becomes thinner. Therefore, the length in the Y direction of the insulating layer inclined region A1 depending on the thickness of the insulating layer 13 on the comb-tooth portion 21 becomes short.

  The Y-direction length of the insulating layer inclined region A1 is preferably, for example, about 0.1 mm. This value is about 1/2 of the Y-direction length (0.2 mm) of the insulating layer inclined region A2 of the comparative example.

  Thus, the occupied area of the wiring layer 12 can be reduced by the amount by which the length in the Y direction of the insulating layer inclined region A1 is shortened. As a result, in the insulating substrate 11, the area 17 for forming the pattern and the pad can be expanded, and the design freedom is increased.

  Desirably, the width W of the comb-tooth portion 21 is 0.4 mm or less (that is, twice or less the length in the Y direction of the insulating layer inclined region A2 of the comparative example shown in FIG. 9). By setting the width W of the comb-tooth portion 21 to 0.4 mm or less, the variation in the thickness (i.e., the height of the surface) of the insulating layer 13 is reduced, whereby the light emitting device 3 is formed on the insulating layer 13. This is because the effect of supporting in a stable state can be easily obtained.

  The wiring layer 12 has one connecting portion 20 and a plurality of comb-tooth portions 21 and is entirely formed in a comb shape. On the other hand, when the connecting portions 20 are formed on both sides of the comb-tooth portion 21 in the Y direction (that is, when the wiring layer 12 is formed in a ladder shape), the insulating layer 13 becomes thicker on the connecting portions 20 Since the change in the height of the surface of the layer 13 becomes large, it is not desirable from the viewpoint of suppressing the inclination of the light emitting device 3.

<Effect of First Embodiment>
As described above, the light emitting unit 1 (optical element unit) according to the first embodiment covers the insulating substrate (substrate) 11, the wiring layer 12 formed on the insulating substrate 11, and the wiring layer 12 The insulating layer 13 and the light emitting devices 3 (optical element chips) arranged in the X direction on the surface of the insulating layer 13 are provided, and the wiring layer 12 includes a connecting portion 20 extending in the X direction, Y from the connecting portion 20 And a plurality of comb teeth 21 extending in the direction and arranged in the X direction. The light emitting device 3 is disposed in a region where the comb teeth 21 of the wiring layer 12 are arranged.

  Since it is comprised in this way, the thickness of the part which covers the comb tooth part 21 of the insulating layer 13 can be made thin, and the length of the Y direction of insulating layer inclined area | region A1 can be shortened. Thus, the distance from the wiring end 25 to the arrangement region of the light emitting device 3 can be shortened, and the area occupied by the wiring layer 12 on the insulating substrate 11 can be reduced. As a result, it is possible to secure a wide area 17 where the pattern or pad is formed on the insulating substrate 11 while suppressing the inclination of the light emitting device 3. The light emitting device 3 can be supported in a stable posture by the plurality of comb teeth 21 arranged in the X direction.

  Further, since the comb-tooth portions 21 have a constant width W and are arranged at a constant interval G, the light emitting device 3 can be supported with an equal force. Moreover, since the unevenness | corrugation of the surface of the insulating layer 13 becomes equal to a X direction, the effect which suppresses the inclination of the light emitting device 3 can be heightened.

  Further, since the distance G between the adjacent comb teeth 21 is larger than the width W of the comb teeth 21, the thickness of the insulating layer 13 on the comb teeth 21 can be made sufficiently thin. Can be enhanced.

  Further, the openings 23 of the wiring layer 12 and the openings 13 b of the insulating layer 13 are formed at positions corresponding to both ends of the light emitting device 3 in the X direction. Can be suppressed from reaching the surface of the light emitting device 3 (the LED 31 side).

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 11 is a plan view showing a light emitting unit 1A (optical element unit) according to the second embodiment. The light emitting unit unit 1A of the second embodiment is different from the light emitting unit unit 1 of the first embodiment in the shape of the wiring layer 12A.

  FIG. 12 is a plan view showing the insulating substrate 11 and the wiring layer 12A of the printed wiring board 10A of the second embodiment. The wiring layer 12A of the printed wiring board 10A has a connecting portion 20 extending in the X direction and a plurality of comb-tooth portions 21A as extending portions extending from the connecting portion 20 in the Y direction. The configuration of the connecting portion 20 is the same as that of the first embodiment.

  The comb-tooth portion 21A of the second embodiment has a comb-tooth portion 211 (first extension portion) having a width W1 and a comb-tooth portion 212 (second extension portion) having a width W2. . The width W1 is thicker than the width W2 (W1> W2). The width W1 of the comb tooth portion 211 and the width W2 of the comb tooth portion 212 are desirably 0.4 mm or less, similarly to the width W of the comb tooth portion 21 of the first embodiment. By setting the thickness to 0.4 mm or less, as described in the first embodiment, the variation in the thickness (that is, the height of the surface) of the insulating layer 13 is reduced, and the light emitting device 3 is stabilized on the insulating layer 13 This is because it is easy to obtain the effect of supporting in the state of

  The intervals between the adjacent comb teeth 211, the intervals between the adjacent comb teeth 212, and the intervals between the adjacent comb teeth 211 and the comb teeth 212 are all the comb teeth 21 according to the first embodiment. Is the same as the interval G of. The width W1 of the comb-tooth portion 211 is wider than the interval G. On the other hand, the width W2 of the comb-tooth portion 212 is narrower than the interval G. That is, W1> G> W2 holds.

  The same number (three in this case) of comb teeth 211 is formed at positions corresponding to both ends of the light emitting device 3 in the X direction. However, the number of the comb-tooth portions 211 is not limited to three, and may be one or more.

  The comb teeth 212 are formed on the inner side in the X direction with respect to the comb teeth 211 at both ends of the light emitting device 3 in the X direction. Here, three comb teeth 212 are formed on the inner side in the X direction with respect to the comb teeth 211 at both ends of the light emitting device 3 in the X direction. However, the number of the comb teeth 212 is not limited to three, and may be one or more.

  The wiring layer 12A has the openings 23 at positions corresponding to both ends of the light emitting device 3 in the X direction as in the first embodiment, but in addition to this, at positions corresponding to the center of the light emitting device 3 in the X direction. , Opening 24. The opening 24 is filled with the insulating layer 13.

  FIG. 13 is a cross-sectional view in the arrow direction of line segment XIII-XIII shown in FIG. 11, that is, a cross-sectional view in a plane across the comb teeth 21 of the wiring layer 12. The wiring layer 12A is covered with the insulating layer 13 as in the first embodiment. The insulating layer 13 is filled between the comb-tooth portion 211 (212) and the light emitting device 3. In addition, the insulating layer 13 is filled between the insulating substrate 11 and the light emitting device 3 in a portion without the comb-tooth portion 211 (212), that is, in the groove portion 22.

  In the second embodiment, at positions (both end portions) corresponding to both ends of the light emitting device 3 in the X direction, a comb-tooth portion 211 (first extension portion) having a wider width than the comb-tooth portion 212 is provided. It is provided. Therefore, the thickness of the insulating layer 13 in the comb-tooth portion 211 is relatively thicker than the thickness of the insulating layer 13 in the comb-tooth portion 212. Therefore, the light emitting device 3 can be supported in a stable state, whereby the inclination of the light emitting device 3 can be suppressed.

  Since the X direction end of the light emitting device 3 is supported by the wide comb teeth portion 211 in this manner, the openings 24 (comb teeth portions 211 and 212 do not exist at positions corresponding to the X direction center of the light emitting device 3 Region) can be provided. However, the opening 24 may not be provided. That is, the comb teeth 212 may be arranged at equal intervals at a position corresponding to the center of the light emitting device 3 in the X direction. Further, the opening 24 may be provided in the wiring layer 12 (FIG. 2) of the first embodiment.

  Here, the wiring layer 12A has three comb teeth 211 at positions corresponding to both ends of the light emitting device 3 in the X direction, but the number of the comb teeth 211 is not limited to three. . However, in order to enhance the effect of suppressing the inclination of the light emitting device 3, it is desirable to provide the same number of comb teeth 211 at positions corresponding to both ends of the light emitting device 3 in the X direction.

  Here, the wiring layer 12A includes the two types of comb-tooth portions 211 and 212 having different widths, but three or more types of comb-tooth portions having different widths in the X direction may be provided. Furthermore, in this case, although the interval between the comb teeth 211, the interval between the adjacent comb teeth 212, and the interval between the adjacent comb teeth 211 and the comb teeth 212 are all set to the constant interval G, May be different from each other.

<Configuration of print head>
Next, the print head 5 to which the light emitting unit 1 (1A) of each embodiment can be applied will be described. FIG. 14 is a schematic view showing the print head 5 having the light emitting unit 1 according to the first embodiment.

  The print head 5 includes the light emitting unit 1, a lens array 52 as a lens unit disposed to face the light emitting device 3 of the light emitting unit 1, and a holder 51 for supporting these.

  The lens array 52 is formed by arranging a large number of refractive index distribution type columnar lens elements 52 a (rod lenses). Here, the lens elements 52a are arranged in two rows in the X direction, and are held by being held between the pair of holding plates 53 in the Y direction. Each lens element 52 a of the lens array 52 has an entrance surface facing the light emitting device 3 and an exit surface opposite to the entrance surface.

  The holder 51 has a first holding unit 51 a holding the light emitting unit 1 and a second holding unit 51 b holding the lens array 52. In the light emitting unit 1 and the lens array 52, the distance from the light emitting surface of the light emitting unit 1 (ie, the surface of the LED 31) to the light incident surface of the lens element 52a is the same as the distance from the light emitting surface of the lens element 52a to the target surface. It is positioned to be

  Light emitted from the LEDs 31 of the light emitting unit 1 is collected by the lens elements 52a of the lens array 52 to form an erect equal-magnification image on a target surface (for example, the surface of the photosensitive drum 61 described later). .

  The print head 5 is used as an exposure device of the electrophotographic image forming apparatus 7 (printer, copier, facsimile machine, etc.) shown in FIG. Note that the light emitting unit unit 1A of the second embodiment may be used instead of the light emitting unit unit 1 of the first embodiment.

<Image forming apparatus>
Next, an image forming apparatus 7 having a print head 5 to which the light emitting unit 1 (A) of each embodiment can be applied will be described.

  FIG. 7 is a view showing the configuration of the image forming apparatus 7 having the print head 5. The image forming apparatus 7 is a color printer provided with process units (image forming units) 6Y, 6M, 6C, 6K for forming yellow (Y), magenta (M), cyan (C) and black (K) images. is there. The process units 6Y, 6M, 6C, 6K are arranged along the transport path of the recording medium P from the upstream side to the downstream side (here, from the right side to the left side).

  Print heads 5Y, 5M, 5C, and 5K (exposure devices) are disposed above the photosensitive drums 61 (described later) of the process units 6Y, 6M, 6C, and 6K. The print heads 5Y, 5M, 5C, and 5K expose the surface of the photosensitive drum 61 based on the image data of each color to form an electrostatic latent image.

  At the lower part of the image forming apparatus 7, a media cassette 70 as a media storage unit for storing recording media P (for example, printing paper), and a hopping roller for feeding the recording media P stored in the media cassette 70 one by one to the transport path 71 and are provided. A registration roller pair 72 for conveying the recording medium P while correcting skew along the conveyance path of the recording medium P delivered from the medium cassette 70 and the recording medium P are conveyed to the process units 6Y, 6M, 6C, 6K A conveyance roller pair 73 is disposed.

  The process units 6Y, 6M, 6C, and 6K have the same configuration except for the toner to be used, and thus will be described as "process unit 6" below. The print heads 5Y, 5M, 5C, and 5K will be described as "print head 5".

  The process unit 6 includes a photosensitive drum 61 as an electrostatic latent image carrier, a charging roller 62 as a charging member, a developing roller 63 as a developer carrier, and a supply roller 64 as a developer supply member. A developing blade 65 as a developer regulating member, a toner cartridge 66 as a developer container, and a cleaning blade 67 as a cleaning member are provided.

  The photosensitive drum 61 is formed by laminating a photosensitive layer (charge generation layer and charge transport layer) on the surface of a metal cylindrical member, and rotates clockwise in the figure.

  The charging roller 62 is disposed to be in contact with the photosensitive drum 61 and follows the photosensitive drum 61 and rotates. The charging roller 62 is applied with a charging voltage to uniformly charge the surface of the photosensitive drum 61. The developing roller 63 is disposed in contact with the photosensitive drum 61 and rotates in the opposite direction to the photosensitive drum 61. The developing roller 63 is applied with a developing voltage, adheres toner (developer) to the electrostatic latent image formed on the surface of the photosensitive drum 61, and develops the toner image (developer image).

  The supply roller 64 is disposed to face the developing roller 63 and rotates in the same direction as the developing roller 63. The supply roller 64 is supplied with a supply voltage, and supplies the toner replenished from the toner cartridge 66 to the developing roller 63. The developing blade 65 is formed by bending a long plate member made of metal, and the bent portion is pressed against the surface of the developing roller 63. The developing blade 65 regulates the thickness of the toner layer on the surface of the developing roller 63.

  The toner cartridge 66 contains toner and is detachably attached to the process unit 6. The toner cartridge 66 supplies toner to the developing roller 63 and the supply roller 64. The cleaning blade 67 removes toner remaining on the surface of the photosensitive drum 61 after transfer.

  Below each process unit 6, a transfer roller 68 as a transfer member is disposed to face the photosensitive drum 61. The transfer roller 68 is applied with a transfer voltage, and transfers the toner image on the surface of the photosensitive drum 61 to the recording medium P passing between the photosensitive drum 61 and the transfer roller 68.

  A fixing unit 74 is disposed on the downstream side (left side in the drawing) of the process units 6Y, 6M, 6C, and 6K in the conveyance direction of the recording medium P. The fixing unit 74 includes a fixing roller 75 and a pressure roller 76 that fix the toner image transferred to the recording medium P to the recording medium P by heat and pressure.

  Further, on the downstream side of the fixing unit 74 in the conveyance direction of the recording medium P, a pair of discharge rollers 77 and 78 for discharging the recording medium P on which the fixing is completed to the outside of the image forming apparatus 7 is provided. Further, a stacker 79 on which the discharged recording medium P is placed is provided above the image forming apparatus 7.

  Note that, in the double-sided printing mode, the double-sided printing unit 69 (FIG. 24) conveys the recording medium P on which the transfer and fixing of the toner image to the surface is completed to the pair of registration rollers 72. (Indicated by a broken line). The description of the duplex printing unit 69 is omitted.

  As the print head 5 of the image forming apparatus 7 configured as described above, the print head 5 (FIG. 14) including the light emitting unit 1 of the first embodiment or the light emitting unit 1A of the second embodiment is used. It can be used.

  The basic operation of the image forming apparatus 7 is as follows. The image forming apparatus 7 executes an image forming operation upon receiving a print command and print data from a host device such as a personal computer. First, the hopping roller 71 is rotated to feed the recording medium P accommodated in the medium cassette 70 one by one to the conveyance path. The recording medium P fed to the conveyance path is conveyed by the registration roller pair 72 and the conveyance roller pair 73 to the process units 6Y, 6M, 6C, and 6K.

  In each process unit 6, after the surface of the photosensitive drum 61 is uniformly charged by the charging roller 62, the surface of the photosensitive drum 61 is exposed by the print head 5 to form an electrostatic latent image. Further, the toner supplied from the toner cartridge 66 is supplied to the developing roller 63 by the supply roller 64, and a toner image having a uniform thickness is formed on the surface of the developing roller 63 by the developing blade 65. The electrostatic latent image formed on the surface of the photosensitive drum 61 is developed by the developing roller 63 to form a toner image. The toner image formed on the surface of the photosensitive drum 61 is transferred to the recording medium P passing between the photosensitive drum 61 and the transfer roller 68. As the recording medium P passes through the process units 6Y, 6M, 6C, 6K, toner images of yellow, magenta, cyan and black are transferred to the recording medium P.

  The recording medium P to which the toner image has been transferred is conveyed to the fixing unit 74, and heat and pressure are applied by the fixing roller 75 and the pressure roller 76, and the toner image is fixed to the recording medium P. The recording medium P on which the toner image is fixed is discharged to the outside of the image forming apparatus 7 by the discharge roller pair 77 and 78, and is stacked on the stacker 79. Thus, the image forming operation is completed.

  Although a tandem-type color printer provided with print heads 5Y, 5M, 5C, and 5K is described here as an example of the image forming apparatus 7, a color printer other than the tandem-type or a monochrome printer may be used. The present invention is not limited to a printer, and may be a copier, a facsimile machine, or a multifunction machine having the functions of a printer and a copier.

<Structure of read head>
In each of the above embodiments, the light emitting unit unit 1 (1A) including the light emitting device 3 (optical element chip) having the LED 31 (light emitting element) as an optical element has been described. However, instead of the light emitting unit 1 (1A) including the light emitting device 3 having the LED 31, a light receiving unit 1C including the light receiving device 3C having the light receiving element may be used. The light receiving unit 1 C (optical element unit) is, for example, a contact image sensor (CIS), and is used for the reading head 8 of the image reading device 9.

  FIG. 16 is a view showing the basic configuration of the read head 8. The reading head 8 has a light receiving unit 1C in which the light receiving device 3C is provided on the surface of the printed wiring board 10. The reading head 8 also includes a lens array 82 as a lens unit disposed to face the light receiving device 3C of the light receiving unit 1C, a light guide 84 for guiding light from a light source (not shown) to a target surface, And a holder 81 for supporting the The upper side (+ Z side) of the holder 81 is covered with a cover 85.

  The lens array 82 is an array of a large number of refractive index distribution type columnar lens elements 82 a (rod lenses). The lens elements 82 a are arranged in two rows in the X direction, and held by being held between the pair of holding plates 83 in the Y direction. The lens array 82 focuses the light from the target surface on the light receiving element of the light receiving unit 1C.

  The holder 81 has a first holding portion 81 a holding the light receiving unit 1 C, a second holding portion 81 b holding the lens array 82, and a third holding portion 81 c holding the light guide 84. The light receiving unit 1C is obtained by replacing the LED 31 of the light emitting unit 1 (FIG. 1) of the first embodiment or the light emitting unit 1A (FIG. 11) of the second embodiment with a light receiving element.

<Configuration of Image Reading Device>
FIG. 17 is a perspective view showing the image reading device 9 having the reading head 8. The image reading device 9 is, for example, a flatbed image scanner. The image reading device 9 includes a housing 92, a document table 93 provided on the upper surface of the case 92, a reading head 8 as an optical head disposed below the document table 93, and an upper side of the document table 93. And a covering lid 94. The document table 93 is made of a material such as glass that transmits visible light, and a document (object to be read) is placed on the surface of the document table 93.

  In order to guide the reading head 8 in the sub scanning direction (Y direction), a pair of guides 95 are provided along the document table 93. Further, the read head 8 is connected to a drive belt 96, and the drive belt 96 is connected to a stepping motor 97. The read head 8 is also connected to the control circuit 91 via a flexible flat cable 98.

  The basic operation of the image reading device 9 is as follows. When a document is placed on the document table 93 and a predetermined switch (for example, a scan button) is pressed, a light source (not shown) attached to the reading head 8 is turned on to illuminate the document on the document table 93. The light reflected by the surface of the document enters the read head 8. The reading head 8 takes in light reflected by the surface of the document while moving in the Y direction by a drive belt 96 driven by a stepping motor 97. The light from the document is condensed on the light receiving element of the light receiving unit 1C by each lens element 82a of the lens array 82. The light signal received by the light receiving element is converted into an electrical signal.

  Note that instead of moving the reading head 8 as described above, the document is conveyed by an ADF (Automatic Document Feeder) so as to pass a predetermined reading position on the document table 93, and the reading head 8 stops at the reading position. The image of the original may be read by

  Although the preferred embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various improvements or modifications can be made without departing from the scope of the present invention. be able to.

  For example, although a printer has been described as an example of an image forming apparatus, the present invention is also applicable to, for example, a copying machine, a facsimile machine, and a multifunction machine. In addition, although a flatbed-type image scanner has been described as an example of the image reading apparatus, any apparatus having a reading function may be used.

  1, 1A, 1B light emitting unit (optical element unit), 1C light receiving unit (optical element unit), 3 light emitting device (optical element chip), 3C light receiving device (optical element chip), 5, 5Y, 5M, 5C, 5K print head, 6, 6Y, 6M, 6C, 6K process unit (image forming unit), 7 image forming apparatus, 8 reading head, 9 image reading apparatus, 10, 10A, 10B printed wiring board, 11 insulating substrate (substrate) 12, 12A, 12B wiring layer, 13 insulating layer, 13b opening, 14 adhesive, 16 opening region, 17 region, 18a, 18b, 18c connection pad, 19 pattern portion, 20 connecting portion, 21, 21A comb tooth portion , 22 grooves, 23, 24 openings, 25 wiring ends, 30 substrates, 3 LED (light emitting element, optical element), 51 holder, 52 lens array (lens unit), 61 photosensitive drum (image carrier), 62 charging roller (charging member), 63 developing roller (developer carrier), 64 supply Roller (supply member), 65 developing blade (layer regulating member), 66 toner cartridge (developer container), 68 transfer roller (transfer member), 74 fixing unit, 81 holder, 82 lens array (lens unit), 92 housing Body, 93 manuscript table, 94 lid, 211 comb-tooth portion (first extension), 212 comb-tooth portion (second extension).

Claims (16)

A substrate,
A wiring layer formed on the substrate;
An insulating layer covering the wiring layer;
An optical element chip having an optical element and fixed to the insulating layer;
The wiring layer is
A connecting portion extending in a first direction on the surface of the substrate;
A plurality of extending portions extending from the connecting portion in a second direction substantially orthogonal to the first direction and arranged in the first direction;
The optical element unit is characterized in that the optical element chip is arranged in a region in which the plurality of extending portions of the wiring layer are arranged.   The optical element unit according to claim 1, wherein the plurality of extension portions have a constant width W in the first direction. The plurality of extension portions are arranged at a constant interval G in the first direction,
The optical element unit according to claim 2, wherein the gap G is larger than the width W of each extension.   The optical element unit according to claim 2 or 3, wherein a width W of each extension portion is 0.4 mm or less.   The plurality of extension portions have a first extension portion having a predetermined width in the first direction, and a second extension portion whose width in the first direction is narrower than the first extension portion. The optical element unit according to claim 1, further comprising: The optical element unit according to claim 5, wherein the first extending portion is located at both ends of the optical element chip in the first direction. The plurality of extension portions are arranged at a constant interval G in the first direction,
The width W1 of the first extension in the first direction is wider than the gap G,
The optical element unit according to claim 5 or 6, wherein a width W2 of the second extending portion in the first direction is smaller than the distance G.   The optical element unit according to any one of claims 1 to 7, wherein the wiring layer has openings at both ends in the first direction of the optical element chip.   The optical element unit according to claim 8, wherein the insulating layer has an opening at a position corresponding to the opening of the wiring layer.   The optical element unit according to any one of claims 1 to 9, wherein the optical element chip is fixed to the surface of the insulating layer by an adhesive.   The optical element unit according to any one of claims 1 to 10, wherein a pad is formed on a region of the substrate where the wiring layer is not formed.   The optical element chip includes a plurality of optical elements arranged in the first direction, and extends in the first direction. The optical element unit according to. An optical element unit according to any one of claims 1 to 12.
A lens unit for focusing light emitted from the optical element on a target surface;
The print head, wherein the optical element is a light emitting element.   An image forming apparatus comprising the print head according to claim 13. An optical element unit according to any one of claims 1 to 12.
A lens unit for focusing light from a document on the optical element;
The reading head characterized in that the optical element is a light receiving element. An image reading apparatus comprising the reading head according to claim 15.

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