JP2009218433A - Light receiving apparatus, method for manufacturing the same, and electronic equipment using the light receiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light receiving apparatus capable of detecting a laser beam at accurate timing even when the laser beam is made obliquely incident on a light receiving surface of a light receiving element. <P>SOLUTION: A laser beam L is made incident in a direction orthogonal to a longitudinal direction of a cylindrical lens 5a, refracted on the surface of the lens 5a, deflected to the center of the lens 5a, and made incident on the light receiving surface of the light receiving element 3 arranged just under the center of the lens 5a. Even when an incident angle α of the laser beam L on a surface position of the lens 5a is large, an incident angle β of the laser beam L on the light receiving surface of the light receiving element 3 is reduced (α>β), and the laser beam L is made incident from a position near to just above the light receiving surface of the light receiving element 3. Thereby, after the incidence of the laser beam L on the surface of the lens 5a, the laser beam L is not irregularly reflected in translucent resin 5 and no error is caused in the detection timing of the laser beam L by the light receiving element 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light receiving device suitable for detection of incident light or a laser beam to be scanned, a manufacturing method thereof, and an electronic apparatus using the same.

  For example, in an electrophotographic image forming apparatus such as a laser beam printer or a digital copying machine, the surface of a photoconductor is scanned with a laser beam and the intensity of the laser beam is controlled so that an image, text, or the like is applied to the photoconductor surface. One main scanning line is written. At this time, in order to detect the writing start timing on the surface of the photosensitive member, a light receiving element is arranged upstream of the photosensitive member in the scanning direction, and the scanning start timing of the photosensitive member is set based on the detection timing of the laser beam by the light receiving element. Thus, the scanning of the photosensitive member by the laser beam is started.

In Patent Documents 1 and 2, a plurality of light receiving elements having different light receiving surfaces are arranged in parallel along the main scanning line of the laser beam, and based on the light reception output timing of each light receiving element that has received the laser beam. The position of each light receiving element in the sub-scanning direction is obtained, and the accurate main scanning timing of the laser beam is obtained.
Japanese Patent Laid-Open No. 11-212004 JP 2003-69004 A

  By the way, if the light receiving surface of the light receiving element becomes dirty, the detection sensitivity of the laser beam is lowered or erroneous detection occurs. For this reason, usually, a small opening is provided in the package of the light receiving element, and the light receiving surface of the light receiving element is disposed behind the opening, or the light receiving surface of the light receiving element is often covered with a translucent resin.

  However, if the light receiving surface of the light receiving element is arranged in the back of the opening of the package or the light receiving surface of the light receiving element is covered with a light transmitting resin, the laser beam is generated within the edge of the opening or the light transmitting resin. Diffuse reflection may cause an error in the detection timing of the laser beam by the light receiving element.

  In particular, when the light receiving element is disposed upstream of the photosensitive member in the scanning direction as described above, the laser beam is incident on the light receiving element from an oblique direction, and the incident angle of the laser beam with respect to the light receiving surface of the light receiving element. Therefore, irregular reflection of the laser beam is likely to occur in the opening of the light receiving element or in the translucent resin, and an error is likely to occur in the detection timing of the laser beam by the light receiving element.

  Conventionally, the irregular reflection of the laser beam when the incident angle of the laser beam becomes large is not considered, and the error in the detection timing of the laser beam due to the irregular reflection of the laser beam has been improved. Not in.

  For example, Patent Documents 1 and 2 attempt to obtain an accurate main scanning timing of a laser beam by using a plurality of light receiving elements. However, irregular reflection of the laser beam occurs in the opening of the light receiving element or in the translucent resin. Thus, if an error occurs in the detection timing of the laser beam, accurate main scanning timing cannot be obtained.

  In addition, when attaching the light receiving element, it is conceivable to reduce the incident angle of the laser beam with respect to the light receiving surface of the light receiving element by directing the light receiving surface of the light receiving element in the light receiving direction of the laser beam. This is not easy, and variations in device performance due to assembly errors are likely to occur.

  Therefore, the present invention has been made to solve the above problems, and even when the laser beam is incident on the light receiving surface of the light receiving element obliquely, that is, the incident angle of the laser beam with respect to the light receiving surface of the light receiving element is large. Another object of the present invention is to provide a light receiving device that can hardly detect irregular reflection of a laser beam in the vicinity of a light receiving surface of a light receiving element and can detect the laser beam at an accurate timing, a manufacturing method thereof, and an electronic device using the same. And

  In order to solve the above problems, a light receiving device of the present invention includes a light receiving element mounted on a lead frame, the light receiving element is connected to the lead frame through a wire, and at least the light receiving element is sealed with a light-transmitting resin. In the light receiving device, a cylindrical or semi-spindle lens is provided integrally with the light-transmitting resin, and incident light is incident on the light receiving element through a cylindrical or semi-spindle lens.

  For example, the cylindrical or semi-spindle lens is formed by molding a part of the translucent resin. Alternatively, the cylindrical type or semi-spindle type lens is provided integrally with the translucent resin so as to overlap the translucent resin surface.

  The cylindrical or semi-spindle lens is made of a high refractive index resin such as polycarbonate or fluorene special epoxy resin.

  On the other hand, the manufacturing method of the present invention is a method of manufacturing a light receiving device including a light receiving element that receives incident light, a step of mounting the light receiving element on a lead frame and die bonding, and the light receiving element on the lead frame by wire bonding. And a step of sealing at least the light receiving element with a translucent resin, and molding a part of the translucent resin into a cylindrical or semi-spindle type lens.

  Further, the manufacturing method of the present invention is a method of manufacturing a light receiving device including a light receiving element that receives incident light, a step of mounting the light receiving element on a lead frame and die-bonding, and the light receiving element to the lead frame by wire bonding. A step of connecting, a step of resin-sealing at least the light receiving element with a translucent resin, and a cylindrical or semi-spindle type lens superimposed on the surface of the translucent resin so that the edge of the translucent resin and the lens is Sealing with light-shielding resin, and integrating the translucent resin and the lens. The method of mounting the lens on the translucent resin may be a method of mounting a separately molded lens, or the lead mold that is primarily molded with the translucent resin is again used as a mold for lens molding. The method may be such that a cylindrical type or semi-spindle type lens is molded on the surface of the translucent resin by performing a secondary mold for molding only the lens. Thereafter, the translucent resin and the edge of the lens are third-molded with the light-shielding resin to integrate them.

  Furthermore, the electronic device of the present invention is an electronic device using a light receiving device that detects the laser beam on a scanning line of the laser beam. The light receiving device includes a light receiving element mounted on a lead frame, and the light receiving element is connected to a wire. Is connected to the lead frame, and at least the light receiving element is sealed with a translucent resin, and a cylindrical type or semi-spindle type lens is integrally provided in the translucent resin. The light receiving device is arranged so that the longitudinal direction of the mold lens is orthogonal to the scanning direction of the laser beam, and the laser beam is incident on the light receiving element through a cylindrical or semi-spindle lens.

  According to the light-receiving device of the present invention, the light-receiving element is sealed with a light-transmitting resin, a cylindrical or semi-spindle lens is integrally provided in the light-transmitting resin, and incident light is cylindrical or semi-spindle type. The light is incident on the light receiving element through the lens. Since the laser beam incident on the lens surface in a direction substantially orthogonal to the longitudinal direction of the cylindrical or semi-spindle lens is refracted on the lens surface and deflected toward the lens center, the lens surface position Even if the incident angle of the laser beam is large, the incident angle of the laser beam with respect to the light receiving surface of the light receiving element becomes small, and the laser beam is incident from directly above the light receiving surface of the light receiving element. For this reason, after the laser beam is incident on the lens surface, the possibility that the laser beam is irregularly reflected in the lens or the translucent resin is extremely low, and no error occurs in the detection timing of the laser beam by the light receiving element. .

  In the state where the lens is arranged so that the longitudinal direction of the lens is orthogonal to the scanning direction of the laser beam, even if the light receiving element or the lens is displaced in the longitudinal direction, the lens is oriented in a direction substantially orthogonal to the longitudinal direction of the lens. The incident angle of the laser beam incident on the surface does not change. Therefore, even if the arrangement position of the light receiving device is slightly shifted, the effect of reducing the incident angle of the laser beam with respect to the light receiving surface of the light receiving element is not impaired. For this reason, it is easy to attach the light receiving device.

  In particular, the surface of the semi-spindle lens has a curvature in both the longitudinal direction of the lens and the direction orthogonal to the longitudinal direction, so that the laser beam is incident from any direction around the optical axis passing through the center of the lens. Even if it comes, the laser beam is refracted on the lens surface and deflected toward the center of the lens, and the incident angle of the laser beam with respect to the light receiving surface of the light receiving element becomes small.

  Further, since the cylindrical or semi-spindle lens is integrated with the light-transmitting resin that seals the light receiving element, irregular reflection of the laser beam occurs between the cylindrical or semi-spindle lens and the light-transmitting resin. There is nothing.

  For example, a cylindrical or semi-spindle lens is formed integrally with the light-transmitting resin by molding a part of the light-transmitting resin or overlapping the surface of the light-transmitting resin.

  The cylindrical or semi-spindle lens is made of a high refractive index resin such as polycarbonate or a fluorene special epoxy resin. In this case, the laser beam is largely refracted on the lens surface, the laser beam is largely deflected toward the center of the lens, and the incident angle of the laser beam with respect to the light receiving surface of the light receiving element becomes sufficiently small.

  On the other hand, in the manufacturing method of the present invention, the light receiving element is resin-sealed with a translucent resin, and a part of the translucent resin is molded into a cylindrical or semi-spindle lens. Alternatively, the light-receiving element is sealed with a light-transmitting resin, a cylindrical or semi-spindle lens is overlapped on the surface of the light-transmitting resin, and the edges of the light-transmitting resin and the lens are sealed with a light-blocking resin. ing. Thereby, a cylindrical type or a semi-spindle type lens can be integrated with translucent resin.

  Furthermore, since the electronic device of the present invention uses the light receiving device of the present invention, the same operations and effects as those of the light receiving device of the present invention can be achieved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 are a perspective view and a sectional view showing Embodiment 1 of the light receiving device of the present invention. In the light receiving device 1 of the present embodiment, the light receiving element 3 is die-bonded on the lead frame 2, and the light receiving element 3 is connected to the lead frame 2 by a bonding wire 4. Then, the translucent resin 5 is molded, the light receiving element 3 is sealed in the translucent resin 5, and the light-shielding resin package 6 is molded, and the edge of the translucent resin 5 is shielded. The resin package 6 is sealed.

  The upper half of the translucent resin 5 is a cylindrical lens 5a. The light receiving surface of the light receiving element 3 is disposed immediately below the center of the cylindrical lens 5a and passes through the center of the cylindrical lens 5a. The optical axis passes through the center of the light receiving surface of the light receiving element 3.

  Further, a step portion 5 b is formed at the edge of the translucent resin 5, and the lower half of the translucent resin 5 is firmly engaged with the light shielding resin 6 by the step portion 5 b.

  The cylindrical lens 5a and the step portion 5b are formed by a mold when the translucent resin 5 is molded.

  The translucent resin 5 is a high refractive index resin such as polycarbonate or fluorene-based special epoxy resin (for example, provided by Nagase Sangyo Co., Ltd.).

  FIG. 3 is a diagram schematically showing an electrophotographic image forming apparatus to which the light receiving device 1 is applied. In this image forming apparatus 11, the laser beam L emitted from the semiconductor laser 12 is incident on the polygon mirror 13, the polygon mirror 13 is rotationally driven, and the laser beam L reflected by the polygon mirror 13 is moved in the main scanning range A. By repeatedly reciprocatingly moving the laser beam L to the photosensitive drum 15 via the optical system 14 and rotating the photosensitive drum 15, the surface of the photosensitive drum 15 is repeatedly scanned in the main scanning direction B by the laser beam L. Images, characters and the like are written on the surface of the photosensitive drum 15 one main scanning line at a time.

  The light receiving device 1 is disposed in the vicinity of the end of the photosensitive drum 15 and detects the laser beam L every time the laser beam L is scanned. Then, the scanning start timing of the photosensitive drum 15 is obtained based on the detection timing of the laser beam L by the light receiving device 1, the intensity modulation of the laser beam L is started from this scanning start timing, and the surface of the photosensitive drum 15 by the laser beam L is started. Is writing to.

  The cylindrical lens 5a of the light receiving device 1 is arranged so that its longitudinal direction is perpendicular to the main scanning direction B (perpendicular to the paper surface of FIG. 3). Therefore, the laser beam L is incident in a direction perpendicular to the longitudinal direction of the cylindrical lens 5a as shown in FIG. 2, is refracted on the surface of the lens 5a and deflected toward the center of the lens 5a, The light enters the light receiving surface of the light receiving element 3 immediately below the center of the lens 5a. At this time, even if the incident angle α of the laser beam L at the surface position of the lens 5a is large, the incident angle β of the laser beam L with respect to the light receiving surface of the light receiving element 3 is small (α> β), and the laser beam L is received by the light receiving element. 3 is incident from just above the light receiving surface. Since the high refractive index resin is applied as the translucent resin 5 as described above, the laser beam L is largely refracted on the surface of the cylindrical lens 5a, and the laser beam L with respect to the light receiving surface of the light receiving element 3 is reflected. The incident angle β is sufficiently small. Further, while the laser beam L scans the surface of the lens 5 a and is incident on the surface, the laser beam L is deflected toward the center of the lens 5 a and is incident on the light receiving surface of the light receiving element 3.

  For this reason, after the laser beam L is incident on the surface of the lens 5a, the possibility that the laser beam L is irregularly reflected in the translucent resin 5 is extremely low, and there is an error in the detection timing of the laser beam L by the light receiving element 3. It does not occur.

  Even if the light receiving device 1 is displaced in the longitudinal direction of the lens 5a, the incident angle of the laser beam L incident on the surface of the lens 5a is not changed in a direction substantially perpendicular to the longitudinal direction of the lens 5a. Therefore, even if the arrangement position of the light receiving device 1 is shifted in the longitudinal direction of the lens 5a, the effect that the incident angle of the laser beam L with respect to the light receiving surface of the light receiving element 3 becomes small is not impaired. For this reason, it is easy to attach the light receiving device 1 and it is difficult for the performance of the image forming apparatus 11 to vary due to an assembly error.

  If there is no lens 5a and the upper surface of the translucent resin 5A is flat as shown in FIG. 4, when the laser beam L reaches the end of the translucent resin 5A, the laser beam L Since it is irregularly reflected in the translucent resin 5A, an error may occur in the detection timing of the laser beam L by the light receiving element 3.

  FIG. 5 is a cross-sectional view showing a modification of the light receiving device of FIGS. 1 and 2. In the light receiving device 1A of this modification, the light receiving element 3 on the lead frame 2 is sealed with a translucent resin 21, and the flat lower surface of the cylindrical lens type lens 22 is superimposed on the flat upper surface of the translucent resin 21. The light-shielding resin package 6 is molded, the edges of the light-transmitting resin 21 and the cylindrical lens 22 are sealed in the light-shielding resin package 6, and the light-transmitting resin package 6 and the light-transmitting resin 21 and the cylindrical type are sealed. The lens 22 is integrated.

  The method of mounting the lens 22 on the translucent resin 21 may be a method of mounting a lens 22 that is separately molded, or the lead frame 21 that is primarily molded by the translucent resin 21 is again mounted. A method may be employed in which the lens 22 is molded on the surface of the translucent resin 21 by performing a secondary mold in which only the lens 22 is molded by moving to a lens molding die. Thereafter, the edges of the translucent resin 21 and the lens 22 are third-molded with a light-shielding resin to integrate both.

  This light receiving device 1A can also be applied to the image forming device 11 of FIG. 3 in the same manner as the light receiving device 1 of FIGS.

  In FIG. 5, when molding the translucent resin 21, the edge of the cylindrical lens 22 is sealed with the translucent resin 21, and the translucent resin 21 and the cylindrical lens 22 are integrated. Also good.

  FIG. 6 is a perspective view and a cross-sectional view showing Embodiment 2 of the light receiving device of the present invention. In the light receiving device 31 of the present embodiment, the light receiving element 33 is die-bonded on the lead frame 32 and the light receiving element 33 is attached to the lead frame 32 by a bonding wire (not shown), as in the light receiving device 1 of FIGS. Wire connection is performed, the translucent resin 35 is molded, the light receiving element 33 is sealed in the translucent resin 35, and the light-shielding resin package 36 is molded, and the edges of the translucent resin 35 are formed. The light shielding resin package 36 is sealed.

  The upper half of the translucent resin 35 is a semi-spindle type lens 35a. The light receiving surface of the light receiving element 33 is disposed immediately below the center of the semi-spindle type lens 35a. The optical axis passing through the center passes through the center of the light receiving surface of the light receiving element 33. The surface of the semi-spindle type lens 35a has a curvature (curved) in both the longitudinal direction and the direction orthogonal to the longitudinal direction, and is a cylindrical type in the light receiving device 1 of FIGS. The shape of the lens 5a is gradually reduced from the center to both ends.

  The semi-spindle type lens 35a is formed by a mold when the translucent resin 35 is molded.

  The lower edge (not shown) of the translucent resin 35 is covered with the light-shielding resin 35 and is firmly engaged with the light-shielding resin 35.

  The translucent resin 35 is a high refractive index resin such as polycarbonate or fluorene special epoxy resin.

  Such a light receiving device 31 is also arranged in the vicinity of the end of the photosensitive drum 15 in the image forming apparatus 11 of FIG. 3 in the same manner as the light receiving device 1 of FIGS. The laser beam L is detected. The scanning start timing of the photosensitive drum 15 is set based on the detection timing of the laser beam L, and writing on the surface of the photosensitive drum 15 by the laser beam L is performed.

  In the image forming apparatus 11 of FIG. 3, the semi-spindle type lens 35a of the light receiving device 31 is arranged so that its longitudinal direction is perpendicular to the main scanning direction B (perpendicular to the paper surface of FIG. 3). The The laser beam L is incident in a direction orthogonal to the longitudinal direction of the semi-spindle type lens 35a, is refracted on the surface of the lens 35a, is deflected toward the center of the lens 35a, and the light receiving element 33 just below the center of the lens 35a. Is incident on the light receiving surface.

  For this reason, after the laser beam L is incident on the surface of the lens 35a, the laser beam L is incident from directly above the light receiving surface of the light receiving element 33, and the laser beam L is irregularly reflected in the translucent resin 35. In other words, no error occurs in the detection timing of the laser beam L by the light receiving element 33.

  Further, since the surface of the semi-spindle lens 35a has a curvature in both the longitudinal direction and the direction orthogonal to the longitudinal direction, the laser beam L is incident on the longitudinal direction of the lens 35a. Even if it comes, the laser beam L is refracted on the surface of the lens 35a and deflected toward the center of the lens 35a.

  That is, even if the laser beam L is incident from any direction around the optical axis passing through the center of the semi-spindle lens 35a, the laser beam L is refracted on the surface of the lens 35a and deflected toward the center of the lens 35a. The incident angle of the laser beam L with respect to the light receiving surface of the light receiving element 33 is reduced.

  For this reason, even if the arrangement position of the light receiving device 31 is shifted in the longitudinal direction of the lens 35 a or the light receiving device 31 is arranged obliquely with respect to the main scanning direction B, the laser beam L with respect to the light receiving surface of the light receiving element 33 The effect of reducing the incident angle is not impaired. For this reason, the light receiving device 31 can be easily attached, and the performance of the image forming apparatus 11 does not easily vary due to an assembly error.

  The present invention is not limited to the above embodiments, and can be variously modified without departing from the scope of the claims. The electronic apparatus of the present invention is not limited to the image forming apparatus, and may be any electronic apparatus that detects the laser beam by arranging the light receiving apparatus of the present invention on the scanning line of the laser beam. Similar effects can be expected.

It is a perspective view which shows Embodiment 1 of the light-receiving device of this invention. It is sectional drawing which shows the light-receiving device of FIG. FIG. 2 is a diagram schematically showing an electrophotographic image forming apparatus to which the light receiving device of FIG. 1 is applied. It is sectional drawing which shows the comparative example with respect to the light-receiving device of FIG. It is sectional drawing which shows the modification of the light-receiving device of FIG. It is a perspective view which shows Embodiment 2 of the light-receiving device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 31 Light-receiving device 2, 32 Lead frame 3, 33 Light-receiving element 4 Bonding wire 5, 35 Translucent resin 5a Cylindrical lens 6, 36 Light-shielding resin package 11 Image forming device 12 Semiconductor laser 13 Polygon mirror 14 Optical system 15 Photosensitive drum 36a Half spindle type lens

Claims (8)

In a light receiving device in which a light receiving element is mounted on a lead frame, the light receiving element is connected to the lead frame via a wire, and at least the light receiving element is sealed with a translucent resin,
A light receiving device, wherein a cylindrical or semi-spindle lens is integrally provided in the light-transmitting resin, and incident light is incident on the light receiving element through a cylindrical or semi-spindle lens.   2. The light receiving device according to claim 1, wherein the cylindrical or semi-spindle lens is formed by molding a part of the translucent resin.   The light receiving device according to claim 1, wherein the cylindrical or semi-spindle lens is provided integrally with the light-transmitting resin so as to overlap the surface of the light-transmitting resin.   2. The light receiving device according to claim 1, wherein the cylindrical or semi-spindle lens is made of a high refractive index resin such as polycarbonate or fluorene special epoxy resin. In a manufacturing method of a light receiving device including a light receiving element that receives incident light,
Mounting the light receiving element on the lead frame and die bonding;
Connecting the light receiving element to the lead frame by wire bonding;
And a step of sealing at least the light receiving element with a translucent resin, and molding a part of the translucent resin into a cylindrical or semi-spindle type lens. In a manufacturing method of a light receiving device including a light receiving element that receives incident light,
Mounting the light receiving element on the lead frame and die bonding;
Connecting the light receiving element to the lead frame by wire bonding;
A step of sealing at least the light receiving element with a translucent resin;
A step of superimposing a cylindrical or semi-spindle lens on the surface of the translucent resin, sealing the translucent resin and the edge of the lens with a light-shielding resin, and integrating the translucent resin and the lens; A method for manufacturing a light receiving device, comprising:   7. The method for manufacturing a light receiving device according to claim 5, wherein the cylindrical or semi-spindle lens is made of a high refractive index resin such as polycarbonate or fluorene special epoxy resin. In an electronic apparatus using a light receiving device that detects the laser beam on a scanning line of the laser beam,
The light receiving device includes a light receiving element mounted on a lead frame, the light receiving element is connected to the lead frame through a wire, and at least the light receiving element is sealed with a translucent resin, and a cylindrical or semi-spindle type lens is provided. It is provided integrally with translucent resin,
The light receiving device is arranged so that the longitudinal direction of the cylindrical or semi-spindle lens is orthogonal to the scanning direction of the laser beam, and the laser beam is incident on the light receiving element through the cylindrical or semi-spindle lens. Electronic equipment using a light receiving device.

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