JP5593891B2 - Surface emitting laser module, optical scanning device, and image forming apparatus - Google Patents

Description

  The present invention relates to a surface emitting laser module, an optical scanning device, and an image forming apparatus.

  In recent years, higher-definition image quality is required in multicolor image forming apparatuses. For this reason, the speed is increasing year by year and it is being used for simple printing as an on-demand printing system. Specifically, by using a two-dimensional array element having a configuration in which surface emitting lasers (VCSEL: Vertical Cavity Surface Emitting LASER) are two-dimensionally arranged, the sub-scanning interval on the photosensitive member is set to 1 / n of the recording density. It is possible to form a matrix configuration of n × m plural dots as unit pixels. Further, it is possible to simultaneously scan with a plurality of light beams.

  Usually, since a semiconductor laser used for optical writing performs APC (Automatic Power Control) control, it is necessary to monitor the light emission amount of the semiconductor laser. With an edge-emitting laser, the amount of light can be monitored by receiving light emitted from the end surface opposite to the light emitting end. However, with a surface-emitting laser, light is emitted to the surface opposite to the emitting surface. Is not emitted, the amount of light cannot be monitored by a method similar to that of the edge emitting laser. Therefore, in the surface emitting laser, various methods for branching a part of the emitted light and monitoring the light amount have been studied and disclosed.

  For example, Patent Document 1 discloses a method in which a beam spiriter is disposed on the emission surface side of a surface emitting laser, light emitted from the surface emitting laser is branched by the beam spiriter, and is detected by a photodetector as monitor light. Has been.

  Further, in Patent Document 2, an aperture formed by a mirror is provided on the exit slope side of the surface emitting laser, and is separated into light passing through the aperture and light reflected by the mirror provided in the aperture, and provided in the aperture. A method of detecting and monitoring light reflected by a reflected mirror with a light receiving element is disclosed.

  Further, Patent Documents 3 and 4 disclose a method in which a light receiving element is arranged outside the emission window of the surface emitting laser package to receive the ambient light of the laser light and monitor the light quantity.

  However, since the method described in Patent Document 1 is a method of branching light to be used by a beam splitter, the light utilization efficiency is lowered, and the beam splitter is expensive, leading to an increase in cost. Have the following problems.

  In addition, the method described in Patent Document 2 requires a special optical component or an optical component for making light incident on the light receiving element, leading to a cost increase and an increase in size. Has a point.

  Further, in the methods described in Patent Documents 3 and 4, it is necessary to separately provide an aperture in order to make the light beam have a desired shape, leading to an increase in cost.

  In view of the above, the present invention has been made in view of the above, and an object thereof is to provide a surface-emitting laser module that can monitor the amount of light at a low cost without reducing the utilization efficiency of light used. Furthermore, it is an object of the present invention to provide an optical scanning apparatus and an image forming apparatus that can form a high-quality image with high reliability.

The present invention includes a surface emitting laser element in which a surface emitting laser is formed on a substrate, a package for installing the surface emitting laser element, and an aperture portion provided on an emission side of the surface emitting laser. The aperture section includes an opening through which the surface emitting laser light passes, and a light receiving element formed in a region where the opening is not provided, and the opening is rectangular. what der being formed on Jo, the light receiving element is divided into two or more, the arithmetic circuit for calculating a difference signal or difference signal in the light receiving elements which are divided into two or more and the sum signal the have characterized Rukoto.

  Further, the invention is characterized in that the light receiving element is divided into two or more.

  Further, the present invention is characterized by having an arithmetic circuit for calculating a difference signal or a difference signal and a sum signal in the light receiving element divided into two or more.

  Further, the present invention is characterized by having a position adjusting unit for adjusting the surface emitting laser element and the aperture unit.

  According to the present invention, the light receiving element has a structure in which a lower electrode, a semiconductor layer, and an upper electrode are laminated.

  According to the present invention, the surface-emitting laser module is used as a light source for optical scanning, and the opening has a longitudinal direction in either the main scanning direction or the sub-scanning direction. It is characterized by being.

  According to the present invention, the aperture section has the light receiving element formed on one surface of a substrate that does not transmit light on which the opening is formed, and the one surface faces the surface emitting laser element. It is a surface.

  Further, the present invention is characterized in that the aperture section has the light receiving element formed on a transparent substrate, and the opening is formed by a region where the light receiving element is not formed. To do.

  Further, the present invention is characterized in that either one of the lower electrode and the upper electrode, and both the lower electrode and the upper electrode are formed of a metal material.

  In the present invention, the metal material is chromium.

  Further, the present invention is characterized in that the aperture portion is installed at an angle inclined with respect to the emission surface of the surface emitting laser element.

  The present invention is also characterized in that the surface-emitting laser element includes a plurality of the surface-emitting lasers formed in an array.

  The present invention also provides an optical scanning device that scans a surface to be scanned with light, the light source having the surface-emitting laser module described above, a light deflection unit that deflects light from the light source, and the light deflection unit. And a scanning optical system for condensing the light deflected by the light onto the surface to be scanned.

  According to another aspect of the invention, there is provided an image carrier, and the above-described optical scanning device that scans the image carrier with light modulated in accordance with image information.

  Further, the present invention is characterized in that there are a plurality of the image carriers, and the image information is multicolor color information.

  According to the present invention, it is possible to provide a surface emitting laser module that can monitor the amount of light without lowering the utilization efficiency of light that is used at low cost. Further, it has high reliability and high quality. An optical scanning device and an image forming apparatus capable of forming an image can be provided.

Configuration diagram of a surface emitting laser module according to the first embodiment Explanatory drawing of the surface emitting laser module in 1st Embodiment Aperture structure diagram Structure of light receiving element (1) Structure of light receiving element (2) Structure of light receiving element (3) Structure of light receiving element (4) Explanatory drawing of alignment of aperture part (1) Explanatory drawing of alignment of aperture part (2) Explanatory drawing of the alignment jig for the aperture Explanatory drawing of alignment of aperture part in surface emitting laser array Structure diagram of surface emitting laser module according to the first embodiment Structural diagram of another surface emitting laser module according to the first embodiment (1) Structural diagram of another surface emitting laser module according to the first embodiment (2) Configuration diagram of surface-emitting laser array in the first embodiment Configuration diagram of laser printer in second embodiment The block diagram of the optical scanning device in 2nd Embodiment The block diagram of the color printer in 3rd Embodiment

  The form for implementing this invention is demonstrated below. In addition, about the same member etc., the same code | symbol is attached | subjected and description is abbreviate | omitted.

[First Embodiment]
The surface emitting laser module in the first embodiment will be described. The surface emitting laser module in the present embodiment includes a surface emitting laser element 10 and an aperture unit 20. The aperture portion 20 has an aperture main body portion 22 having an opening 21 through which laser light passes. A light receiving element 23 is provided on the surface of the aperture main body portion 22 on which the surface emitting laser element 10 is provided. Is formed. Since the light receiving element 23 is not formed in the opening 21, the light passing through the opening 21 is not blocked. For this reason, the light receiving element 23 can receive only light blocked by the aperture portion 20, and does not reduce the amount of light passing through the opening portion 21. A coupling lens (not shown) may be provided between the surface emitting laser element 10 and the aperture unit 20 as necessary.

  The light receiving element 23 is bonded to the aperture body 22 with a resin material such as a curable resin, and the light received by the light receiving element 23 is output as an output monitor signal from the electrode terminal 24 to the write control unit 30. Entered. The writing control unit 30 compares the light beam intensity in the surface emitting laser element 10 measured by the light receiving element 23 with a predetermined reference value or the like, and the output of the surface emitting laser in the surface emitting laser element 10 is predetermined. Current control is performed so that the value becomes. That is, the surface emitting laser element 10 is controlled by the write signal from the write control unit 30. The light beam intensity measured by the light receiving element 23 is stored until the next measurement, and the light beam intensity emitted from the surface emitting laser element 10 can be kept constant.

  Next, the surface emitting laser element will be described with reference to FIG. In the surface emitting module 100 according to the present embodiment shown in FIG. 2A, the surface emitting laser element 10 is installed in the package 80, and the side facing the surface emitting laser element 10 is shown in FIG. Is provided with an aperture 20 (not shown). The surface-emitting laser element 10 has a surface-emitting laser array. For example, as shown in FIG. 2B, a plurality of surface-emitting lasers emit light on the chip of the surface-emitting laser element 10. The region 11 is arranged at a predetermined position. FIG. 2B is an enlarged view of a part of the surface emitting laser element 10 surface. Thus, when the surface emitting laser element 10 has a surface emitting laser array, the coordinate positions of the light emitting regions 11 of the respective surface emitting lasers are different from each other. The table of the correction amount corresponding to the arrangement of the laser beam is used, and by using this table, the writing control unit 30 controls the light emitting areas 11 of the different surface emitting lasers so that the emission light amounts are substantially the same. Can do.

(Aperture part)
Next, the aperture unit used in the surface emitting laser module according to the present embodiment will be described with reference to FIG. FIG. 3A shows an aperture unit 30 using the light receiving element 23 having the structure shown in FIG. The aperture 20 has a rectangular opening 21 that extends long in the sub-scanning direction. Of the light of the light spot 40 irradiated by the surface emitting laser of the surface emitting laser element 10, the light in the area of the opening 21 passes, but the area in which the opening 21 is not formed, that is, the light receiving element 23 is provided. Since the light of the light spot 40 is irradiated to the area where the light is applied, the light amount can be detected. The light receiving element 23 is formed in the vicinity of the opening 21 of the aperture portion 20 and is not formed in the peripheral portion of the aperture portion 20. In addition, an electrical signal corresponding to the amount of light detected by the light receiving element 23 is output from the terminal unit 24.

  FIG. 3B is different from FIG. 3A in the shape of the light receiving element. Specifically, the light receiving element 23a is formed on substantially the entire area of the aperture portion 20a excluding the opening 21 on the surface where the surface emitting laser element 10 is disposed.

  FIG. 3C illustrates a shape in which the light receiving element is divided. Specifically, in the aperture portion 20b, the light receiving element 23b is divided into two in the region where the light spot 40 is irradiated. The light receiving element may be divided into two or more, and may have a shape other than a quadrangle, for example, a polygon or a circle.

  As shown in FIG. 3D, the opening 21c formed in the aperture 20c may be a rectangular opening that extends long in the main scanning direction. In this case, the light receiving element 23c is an opening. It is formed in a shape having an opening corresponding to the shape of 21c.

  Note that the opening 21 formed in the aperture 20 has a rectangular shape extending in the sub-scanning direction and a rectangular shape extending in the main scanning direction. This is because the shape of the light beam that passes through the opening 21 is made constant, thereby suppressing variations and fluctuations in the shape of the light beam and providing high definition in the sub-scanning direction or main scanning direction. This is to enable high-density writing, whereby high-quality writing can be stably performed on a photoconductor described later.

  In the specification of the present application, the aperture portions 20, 20a, 20b, and 20c in FIG. 3 may be described with the aperture portion 20 as a representative, and the openings 21 and 21c are described with the opening 21 as a representative. The light receiving elements 23, 23a, 23b, and 23c may be described using the light receiving element 23 as a representative.

  As described above, the light receiving element 23 forming method in the aperture portion 20 includes a method of applying a curable resin or an adhesive on the surface of the aperture main body 22 and attaching the light receiving device 23, and a method of fixing with a screw or the like. In addition to this, there is a method of forming the light receiving element 23 directly on the surface of the aperture body 22.

(Light receiving element)
Next, a method for forming the light receiving element directly in the aperture portion will be described. As a method for manufacturing an aperture portion using a substrate made of stainless steel or the like, for example, an opening 21 is first formed in a substrate made of stainless steel or the like, and a light receiving element is formed. There is a method of forming the opening 21 after the formation. Hereinafter, a method for forming a light receiving element in these cases will be described with reference to FIGS.

  As shown in FIG. 4A, the light receiving element in the aperture portion is formed with a lower electrode 51 made of Cr (chromium) on a substrate 50 made of stainless steel, and n-type a-Si (amorphous silicon) on the lower electrode 51. ) Layer 52, and an upper electrode 59 made of ITO (Indium Tin Oxide) is formed on a part of the n-type a-Si layer 52.

  4B, a lower electrode 51 made of Cr is formed on a substrate 50 made of stainless steel, and an n-type a-Si layer 52 and a p-type a-Si layer 53 are formed on the lower electrode 51. A structure in which an upper electrode 59 made of Au (gold) is formed on a part of the p-type a-Si layer 53 by stacking may be used.

Further, as shown in FIG. 4C, a lower electrode 51 made of chromium is formed on a substrate 50 made of stainless steel, and an n-type a-Si layer 52, an i-type Si layer 54 and a p-type are formed on the lower electrode 51. A structure in which the a-Si layer 53 is stacked and an upper electrode 59 made of SnO ₂ (tin oxide) is formed on a part of the p-type a-Si layer 53 may be used.

The n-type a-Si layer 52, the p-type a-Si layer 53, and the i-type a-Si layer 54 are formed by plasma CVD (Chemical Vapor Deposition) and are necessary using SiH ₄ as a source gas. Depending on the case, an n-type or p-type impurity is doped.

The lower electrode 51 and the upper electrode 59 may use other conductive metal materials or conductive metal oxide materials such as Al (aluminum) and Ag (silver) in addition to Cr, ITO, Au, and SnO _2. . The lower electrode 51 and the upper electrode 59 can be formed by a method such as vacuum deposition or sputtering.

  In addition to stainless steel, the substrate 50 may be made of a metal material such as Ni (nickel), heat-resistant ceramics, heat-resistant plastic, or the like, or may be subjected to surface treatment such as formation of an oxide film on the surface.

  Further, as shown in FIG. 5A, a lower electrode 51 made of Cr is formed on a substrate 50 made of stainless steel, and a p-type p-Si (polysilicon) layer 55 and an n + type p− are formed on the lower electrode 51. A structure in which the Si layer 56 is stacked and an upper electrode 59 made of Au (gold) is formed on a part of the n + type p-Si layer 56 may be used.

  Further, as shown in FIG. 5B, a lower electrode 51 made of Cr is formed on a substrate 50 made of stainless steel, and a p-type c-Si (single crystal silicon) layer 57 and an n + type c are formed on the lower electrode 51. A structure in which the -Si layer 58 is stacked and an upper electrode 59 made of Au (gold) is formed on a part of the n + -type c-Si layer 58 may be used.

Further, as shown in FIG. 5C, a lower electrode 51 made of Cr is formed on a substrate 50 made of stainless steel, and an n-type or i-type a-Si layer 61, an n-type c- A structure in which an Si layer 62 and a p-type or i-type a-Si layer 63 are stacked, and an upper electrode 59 made of SnO ₂ (tin oxide) is formed on a part of the p-type or i-type a-Si layer 63. It may be.

  Further, the aperture portion may have a structure using a transparent substrate 71 that transmits light from the surface emitting laser 10. Specifically, as a method of forming such an aperture portion, for example, a mask made of metal or the like is placed in a region to be the opening portion 21 on a transparent substrate 71 such as glass, and a light receiving element is formed. A method of forming the opening 21 by removing a mask made of metal or the like, and after forming a light receiving element on a transparent substrate 71 such as glass, a photoresist is applied, and exposure and development are performed by an exposure apparatus. Thus, a resist pattern having an opening is formed in a region to be the opening 21, and the opening 21 is formed by removing a light receiving element in a region where the resist pattern is not formed by RIE (Reactive Ion Etching) or the like. There are methods. Hereinafter, a method for forming a light receiving element in these cases will be described with reference to FIGS.

  For example, as shown in FIG. 6A, the light receiving element in the aperture portion includes a lower electrode 51 made of Cr (chromium) formed on a transparent substrate 71 made of glass, and an n-type a− on the lower electrode 51. In this structure, an Si (amorphous silicon) layer 52 is formed, and an upper electrode 59 made of ITO (Indium Tin Oxide) is formed on a part of the n-type a-Si layer 52.

  6B, a lower electrode 51 made of Cr is formed on a transparent substrate 71 made of glass, and an n-type a-Si layer 52 and a p-type a-Si layer are formed on the lower electrode 51. A structure in which 53 is stacked and an upper electrode 59 made of Au (gold) is formed on a part of the p-type a-Si layer 53 may be used.

6C, a lower electrode 51 made of chromium is formed on a transparent substrate 71 made of glass, and an n-type a-Si layer 52, an i-type Si layer 54, and a lower electrode 51 are formed on the lower electrode 51. A structure in which the p-type a-Si layer 53 is stacked and an upper electrode 59 made of SnO ₂ (tin oxide) is formed on a part of the p-type a-Si layer 53 may be used.

  The transparent substrate 71 may be made of a transparent inorganic material or organic material other than glass.

  7A, a lower electrode 51 made of Cr is formed on a transparent substrate 71 made of glass, and a p-type p-Si (polysilicon) layer 55 and an n + type are formed on the lower electrode 51. A structure in which the p-Si layer 56 is stacked and an upper electrode 59 made of Au (gold) is formed on a part of the n + -type p-Si layer 56 may be used.

  Further, as shown in FIG. 7B, a lower electrode 51 made of Cr is formed on a transparent substrate 71 made of glass, and a p-type c-Si (single crystal silicon) layer 57 and n + are formed on the lower electrode 51. A structure in which the mold c-Si layer 58 is stacked and an upper electrode 59 made of Au (gold) is formed on a part of the n + c-Si layer 58 may be used.

Further, as shown in FIG. 7C, a lower electrode 51 made of Cr is formed on a transparent substrate 71 made of glass, and an n-type or i-type a-Si layer 61, n-type is formed on the lower electrode 51. A c-Si layer 62 and a p-type or i-type a-Si layer 63 are stacked, and an upper electrode 59 made of SnO ₂ (tin oxide) is formed on a part of the p-type or i-type a-Si layer 63. It may be of the same structure.

  6 and 7, since the transparent substrate 71 is used, either the lower electrode 51 or the upper electrode 59 is used so that light does not pass through the region where the light receiving element is formed. One or both are made of a material that does not transmit light. Specifically, as such a material, a metal material is preferable, and Cr that is often used as a material for shielding light is more preferable. Thereby, light is blocked in the region where the light receiving element is formed, and the region where the light receiving element is not formed becomes the opening 21 through which the laser light is transmitted.

  The light receiving element described above has been described using Si as a semiconductor material, but other semiconductor materials such as InGaAs-based and GaAs-based compound semiconductor materials may be used. However, since these compound semiconductor materials are expensive, it is preferable to use silicon from the viewpoint of cost.

(Aperture installation method)
Next, when the light receiving element is divided into two or more in the aperture unit 20, a method of installing the aperture unit 20 will be described. The case where the light receiving element is divided into two or more is, for example, the case where the light receiving element 23b is divided into two, the light receiving element 23b1 and the light receiving element 23b2, as in the aperture portion 20b shown in FIG. Hereinafter, an installation method in this case will be described. A detection signal corresponding to the amount of received light can be extracted independently from each of the light receiving element 23b1 and the light receiving element 23b2. The detection signal from the light receiving element 23b1 is set as the detection signal A, and the detection signal from the light receiving element 23b2 is detected as the detection signal. An arithmetic circuit 41 is provided for calculating the difference between the detection signal A and the detection signal B. The arithmetic circuit 41 is provided in the write control unit 30 and the like.

  As shown in FIG. 8A, when the light spot 40 is formed by the light emitted from the surface emitting laser element on the light receiving element 23b of the aperture portion 20b, the center of the light spot is shifted to the light receiving element 23b1 side. It can be seen that the value of the detection signal A-detection signal B is positive and the center of the light spot 40 is shifted to the left in the drawing. Further, as shown in FIG. 8B, when the center of the light spot is irradiated with being shifted toward the light receiving element 23b2, the value of the detection signal A−the detection signal B becomes negative, and the center of the light spot 40 is illustrated. As can be seen from FIG. For this reason, by adjusting the position of the aperture 20b with respect to the surface emitting laser so that the value of the detection signal A-detection signal B becomes 0, the center 40 of the light spot receives the light as shown in FIG. The center position between the element 23b1 and the light receiving element 23b2 can be adjusted.

  FIG. 8 shows the case of the aperture portion 20b in which the light receiving element 23b is divided into right and left in the drawing. As shown in FIG. 9A, in the drawing, the light receiving element 23d is the light receiving element 23d1 and the light receiving element 23d2. Also in the case of the aperture part that is divided vertically, the alignment can be performed by the same method.

  Further, as shown in FIG. 9B, the light receiving element is divided into a light receiving element 23e1, a light receiving element 23e2, a light receiving element 23e3, and a light receiving element 23e4 vertically and horizontally, and is divided into four light receiving elements 23e1, 23e2, and light receiving elements. By using the detection signal A, the detection signal B, the detection signal C, and the detection signal D detected at 23e3 and the light receiving element 23e4, the arithmetic circuit 41 takes the difference between them, thereby easily aligning the light spot 40 in the vertical and horizontal directions. Can be done.

  In this way, when the light receiving elements are divided, the relative position between the aperture unit 20 and the surface emitting laser 10 can be easily obtained by calculating the difference between the detection signals in the respective light receiving elements in the arithmetic circuit 41. Therefore, a high performance surface emitting laser module can be obtained.

  Next, a method for aligning the aperture part will be described. Specifically, as an example, as shown in FIG. 10, there is a method of using an adjustment jig 301 as a method of aligning the aperture portion 20b. The adjustment jig 301 is provided with a plate spring 302 and an adjustment screw 303, and the aperture portion 20 b is installed between the plate spring 302 and the adjustment screw 303 to emit a surface emitting laser in the surface emitting laser element 10. In this state, alignment is performed by turning the adjustment screw 303 so that the difference between the detection signal from the light receiving element 23b1 and the detection signal from the light receiving element 23b2 becomes zero. In this way, at a position where the difference between the detection signal from the light receiving element 23b1 and the detection signal from the light receiving element 23b2 becomes zero, the detection signal is fixed to a package (not shown) or the like with a curable resin or the like. Further, the package may include the above-described adjustment jig 301. In this case, the aperture portion 20b is fixed to the adjustment jig 301. The adjustment jig 301 corresponds to a position adjustment unit.

  Next, a method for aligning an aperture portion in which a plurality of light receiving elements are provided in the surface emitting laser element 10 in which a surface emitting laser array having a plurality of surface emitting lasers is formed will be described with reference to FIG. As described above, for example, the aperture unit 20b shown in FIG. 3C includes two light receiving elements 23b and 23b2 as the aperture unit provided with a plurality of light receiving elements. This case will be described below.

  In the surface-emitting laser element 10, a plurality of surface-emitting lasers are arranged along the sub-scanning direction, and the opening 21 in the aperture portion 20b is along the arrangement of these surface-emitting lasers, that is, along the sub-scanning direction. It is formed to extend long. In this case, if the aperture 20b is arranged at a desired position, a plurality of surfaces are provided along the center of the opening 21 between the light receiving element 23b1 and the light receiving element 23b2, as shown in FIG. The centers of the light spots 40a, 40b and 40c formed by the light emitting laser are located.

  By the way, as shown in FIG. 11B, when the aperture portion 20b has a rotational shift with respect to the surface emitting laser element 10, the difference between the detection signal A and the detection signal B is obtained, and A−B = 0. It is not possible to eliminate the rotational misalignment simply by adjusting so that That is, in the light spot 40a, there are more detection signals in the light receiving element 23b2 than in the light receiving element 23b1, and AB <0, and in the light spot 40c, there are fewer detection signals in the light receiving element 23b2 than in the light receiving element 23b1, Although B> 0, the detection signal in the light spot 40a and the detection signal in the light spot 40c cancel each other, so that even when a rotational deviation occurs, A−B = 0 as a whole.

  In this case, the rotational deviation can be adjusted by calculating the sum of the detection signal A and the detection signal B in the arithmetic circuit 41. Specifically, by rotating the aperture portion 20b in the direction indicated by the arrow R so that A + B is minimized, the rotational deviation can be eliminated.

(Surface emitting laser module)
Next, the surface emitting module in the present embodiment will be described. The surface emitting laser module in the present embodiment includes a surface emitting laser element 10 and an aperture portion in which a light receiving element is formed.

  The surface emitting laser module in the present embodiment will be described based on FIG. FIG. 12A is a cross-sectional view of the surface emitting laser module according to the present embodiment, and FIG. 12B is a top view of the aperture portion.

  This surface-emitting laser module has a package 80 in which a concave portion made of ceramics or the like is formed, a surface-emitting laser element 10, and an aperture portion 70 in which a light-receiving element 72 is formed on a transparent substrate 71 made of glass. . The structure of the aperture 70 in the region where the light receiving element 72 is formed is the structure shown in FIG. 6 or FIG. Further, the package 80 is provided with a recess, and the surface emitting laser element 10 is installed on the bottom surface 80a of the recess. In the surface emitting laser element 10, an aperture portion 70 that also serves as a cover glass is installed in the light emitting direction of the surface emitting laser light. The aperture unit 70 has a light receiving element 72 formed in a predetermined region on a transparent substrate 71 made of glass or the like, and a region where the light receiving element 72 is not formed has an opening 73 through which light from the surface emitting laser passes. Become.

  The aperture part 70 is installed so that the light receiving element 72 and the surface emitting laser element 10 face each other, the opening 73 is formed in a substantially rectangular shape, and the sub-scanning direction is the longitudinal direction of the opening 73. It is installed to become. An electrode terminal 74 is drawn out from the light receiving element 72, is connected to the package 80 via a solder bump 81, and is wired inside the package 80 by a wire. Therefore, the signal detected by the light receiving element 72 is output to the outside of the package 80 via the wire and the terminal provided on the outside of the package 80.

  The material constituting the package 80 may be plastic as well as ceramics, and the surface of the transparent substrate 71 made of glass prevents surface reflection from the substrate 71 and has characteristics due to the return light of the surface emitting laser. In order to prevent the decrease, it is preferable that the surface is coated with an AR coating (Anti Reflection Coat). Moreover, you may use a flexible substrate etc. for the wiring from the electrode terminal 74. FIG.

  Further, the surface emitting laser module in the present embodiment may have a structure shown in FIG. FIG. 13A is a cross-sectional view of the surface emitting laser module according to the present embodiment, and FIG. 13B is a top view of the aperture portion.

  This surface emitting laser module has a package 80 formed of a concave portion made of ceramic or the like, a surface emitting laser element 10, and an aperture portion 75 in which a light receiving element 72 is formed on a substrate 50. The structure of the aperture portion 75 in the region where the light receiving element 72 is formed is the structure shown in FIG. 4 or FIG.

  The aperture part 75 is installed so that the light receiving element 72 and the surface emitting laser element 10 face each other. The aperture 75 is provided with an opening 77 through which light from the surface emitting laser passes, and a light receiving element 72 is formed in a predetermined region on the substrate 50 excluding the opening 77. The opening 77 is formed in a substantially rectangular shape, and is installed such that the sub-scanning direction is the longitudinal direction of the opening 77. Further, a transparent cover glass 78 is provided on the surface of the substrate 50 opposite to the side where the surface emitting laser element 10 is provided so as to cover the opening 77. Furthermore, an electrode terminal 74 is drawn out from the light receiving element 72, is connected to the package 80 via a solder bump 81, and is wired inside the package 80 by a wire. Therefore, the signal detected by the light receiving element 72 is output to the outside of the package 80 via the wire and the terminal provided on the outside of the package 80.

  Furthermore, the surface emitting laser module in the present embodiment may have a structure shown in FIG. FIG. 14A is a cross-sectional view of the surface emitting laser module according to the present embodiment, and FIG. 14B is a top view of the aperture portion.

  This surface-emitting laser module includes a package 80 made of a ceramic or the like having a recess, the surface-emitting laser element 10, a metal cap 82 installed on the upper surface of the package 80, and the surface-emitting laser light from the metal cap 82. It has an aperture portion 70a in which a light receiving element 72 is formed on a transparent substrate 71a made of glass placed on the exit side. The aperture part 70a has the structure shown in FIG. 6 or FIG. 7, and the metal cap 82 and the aperture part 70a are joined by low-melting glass. Further, a ring 83 for seam welding is provided on the side of the package 80 connected to the metal cap 82, that is, the side where the surface emitting laser element 10 is provided, and the metal cap 82 is a ring for seam welding. 83 is joined by seam welding. The electrode terminal 74 provided in the aperture portion 70 a is soldered to the terminal on one side of the flexible cable 84 provided in the metal cap 82, and the terminal on the other side is packaged via the solder bump 81. 80, and wired inside the package 80 by wires. Therefore, the signal detected by the light receiving element 72 is output to the outside of the package 80 via the wire and the terminal provided on the outside of the package 80.

  The aperture portion 70a also serves as a cover glass. A light receiving element 72 is formed in a predetermined region on a transparent substrate 71a made of glass or the like, and a region where the light receiving element 72 is not formed is a surface emitting laser light. Becomes the opening 73 through which the. The opening 73 is formed in a substantially rectangular shape, and is installed such that the sub-scanning direction is the longitudinal direction of the opening 73.

  The metal cap 82 can be made of a material other than metal. For example, a material such as ceramics or plastic may be used. In this case, it is preferable to use a material that does not allow external dust or the like to enter, a material that the surface emitting laser element 10 does not deteriorate due to the influence of oxygen or moisture, and a method for joining the package 80 by a method other than seam welding. Be joined.

  In addition, the aperture 70a joined to the metal cap 82 is such that light from the surface emitting laser in the surface emitting laser element 10 is reflected on the surface of the transparent substrate 71 or the like and does not enter the surface emitting laser again as return light. As described above, the surface emitting laser is installed to be inclined with respect to a plane perpendicular to the light emission direction.

  The aperture portions 70, 70a, and 75 described above are formed with a structure corresponding to the aperture portions 20, 20a, 20b, and 20c shown in FIG. When the aperture body 22 is made of a transparent substrate, the opening 21 is not formed, and the area where the light receiving element 23 is not formed corresponds to the opening 21. In this area, Light is transmitted through the transparent substrate.

(Surface emitting laser array)
Next, in the surface emitting laser module according to the present embodiment, a case where the surface emitting laser element has a surface emitting laser array formed by a plurality of surface emitting lasers will be described. In this surface emitting laser array, a plurality of surface emitting lasers are two-dimensionally formed.

  The surface emitting laser array 200 will be described with reference to FIG. In the surface emitting laser array 200, light emitting units 210 corresponding to a plurality (21 in this case) of surface emitting lasers are arranged on the same substrate. The X-axis direction is the main scanning corresponding direction, and the Y-axis direction is the sub-scanning corresponding direction. The plurality of light emitting units 210 are arranged at equal intervals d2 when all the light emitting units 210 are orthogonally projected onto a virtual line extending in the Y-axis direction. In this way, the 21 light emitting units 210 are two-dimensionally arranged. In the present specification, the “light emitting part interval” means the distance between the centers of the two light emitting parts 210. Further, FIG. 15 shows that the number of light emitting units 210 is 21, but the number of light emitting units 210 may be plural, and for example, the number of light emitting units 210 may be 40. .

  Further, in the surface emitting laser array 200, the intervals between the light emitting portions when the respective light emitting portions are orthogonally projected onto a virtual line extending in the sub-scanning corresponding direction are equal intervals d2, and therefore, a photosensitive later described by adjusting the lighting timing. It can be understood that the configuration is the same as the case where the light emitting units are arranged at equal intervals in the sub-scanning direction on the body drum.

  For example, if the distance d2 is 2.65 μm and the magnification of the optical system of the optical scanning device described later is doubled, high-density writing of 4800 dpi (dots / inch) can be performed. Of course, if the number of light emitting portions in the main scanning correspondence direction is increased, or the array arrangement is configured such that the pitch d1 in the sub scanning correspondence direction is narrowed and the interval d2 is further reduced, or the magnification of the optical system is lowered, the higher the number. Densification is possible, and higher quality printing is possible. Note that the writing interval in the main scanning direction can be easily controlled by the lighting timing of the light emitting unit.

  By the way, in the surface emitting laser array 200 in the present embodiment, the groove between two adjacent light emitting units 210 is preferably 5 μm or more for electrical and spatial separation of each light emitting unit. This is because if it is too narrow, it becomes difficult to control etching during production. Further, the mesa size (length of one side) is preferably 10 μm or more. This is because if it is too small, heat will be accumulated during operation and the characteristics may be deteriorated.

  Further, instead of the surface emitting laser array 200 in which the surface emitting lasers are two-dimensionally arranged as described above, a surface emitting laser array in which the surface emitting lasers in the present embodiment, which become the light emitting unit 210, are arranged one-dimensionally may be used. Good.

[Second Embodiment]
Next, a second embodiment will be described. The present embodiment is a laser printer 1000 as an image forming apparatus using the surface emitting laser module in the first embodiment.

  A laser printer 1000 according to the present embodiment will be described with reference to FIG. The laser printer 1000 according to this embodiment includes an optical scanning device 1010, a photosensitive drum 1030, a charging charger 1031, a developing roller 1032, a transfer charger 1033, a charge eliminating unit 1034, a cleaning unit 1035, a toner cartridge 1036, a paper feeding roller 1037, a feeding roller. A paper tray 1038, a registration roller pair 1039, a fixing roller 1041, a paper discharge roller 1042, a paper discharge tray 1043, a communication control device 1050, and a printer control device 1060 that comprehensively controls each of the above parts are provided. These are housed in predetermined positions in the printer housing 1044.

  The communication control device 1050 controls bidirectional communication with a host device (for example, a personal computer) via a network or the like.

  The photosensitive drum 1030 is a cylindrical member, and a photosensitive layer is formed on the surface thereof. That is, the surface of the photoconductor drum 1030 is a scanned surface. The photosensitive drum 1030 rotates in the direction indicated by the arrow X.

  The charging charger 1031, the developing roller 1032, the transfer charger 1033, the charge removal unit 1034, and the cleaning unit 1035 are each disposed in the vicinity of the surface of the photosensitive drum 1030. Then, along the rotation direction of the photosensitive drum 1030, the charging charger 1031 → the developing roller 1032 → the transfer charger 1033 → the discharging unit 1034 → the cleaning unit 1035 are arranged in this order.

  The charging charger 1031 uniformly charges the surface of the photosensitive drum 1030.

  The optical scanning device 1010 scans the surface of the photosensitive drum 1030 charged by the charging charger 1031 with a light beam modulated based on image information from the host device, and corresponds to the image information on the surface of the photosensitive drum 1030. A latent image is formed. The latent image formed here moves in the direction of the developing roller 1032 as the photosensitive drum 1030 rotates. The configuration of the optical scanning device 1010 will be described later.

  Toner cartridge 1036 stores toner, and this toner is supplied to developing roller 1032.

  The developing roller 1032 causes the toner supplied from the toner cartridge 1036 to adhere to the latent image formed on the surface of the photosensitive drum 1030 to visualize the image information. Here, the latent image to which the toner is attached (hereinafter also referred to as “toner image” for the sake of convenience) moves in the direction of the transfer charger 1033 as the photosensitive drum 1030 rotates.

  Recording paper 1040 is stored in the paper feed tray 1038. A paper feed roller 1037 is disposed in the vicinity of the paper feed tray 1038. The paper feed roller 1037 takes out the recording paper 1040 one by one from the paper feed tray 1038 and conveys it to the registration roller pair 1039. The registration roller pair 1039 temporarily holds the recording paper 1040 taken out by the paper supply roller 1037, and in the gap between the photosensitive drum 1030 and the transfer charger 1033 according to the rotation of the photosensitive drum 1030. Send it out.

  A voltage having a polarity opposite to that of the toner is applied to the transfer charger 1033 in order to electrically attract the toner on the surface of the photosensitive drum 1030 to the recording paper 1040. With this voltage, the toner image on the surface of the photosensitive drum 1030 is transferred to the recording paper 1040. The recording sheet 1040 transferred here is sent to the fixing roller 1041.

  In the fixing roller 1041, heat and pressure are applied to the recording paper 1040, whereby the toner is fixed on the recording paper 1040. The recording paper 1040 fixed here is sent to the paper discharge tray 1043 via the paper discharge roller 1042 and is sequentially stacked on the paper discharge tray 1043.

  The neutralization unit 1034 neutralizes the surface of the photosensitive drum 1030.

  The cleaning unit 1035 removes the toner remaining on the surface of the photosensitive drum 1030 (residual toner). The surface of the photosensitive drum 1030 from which the residual toner has been removed returns to the position facing the charging charger 1031 again.

  Next, the optical scanning device 1010 will be described with reference to FIG. The optical scanning device 1010 controls the light source unit 1100, a coupling lens and an aperture plate (not shown), a cylindrical lens 1113, a polygon mirror 1114, an fθ lens 1115, a toroidal lens 1116, two mirrors (1117, 1118), and the above-described units. A control device (not shown) for controlling the operation is provided. As the light source unit 1100, the light source unit 1100 including the surface emitting laser module according to the first embodiment is used.

  The cylindrical lens 1113 condenses the light output from the light source unit 1100 in the vicinity of the deflection reflection surface of the polygon mirror 1114 via the mirror 1117.

  The polygon mirror 1114 is made of a regular hexagonal columnar member having a low height, and six deflection reflection surfaces are formed on the side surface. Then, it is rotated at a constant angular velocity in the direction indicated by the arrow Y by a rotation mechanism (not shown).

  Accordingly, the light emitted from the light source unit 1100 and condensed near the deflection reflection surface of the polygon mirror 1114 by the cylindrical lens 1113 is deflected at a constant angular velocity by the rotation of the polygon mirror 1114.

  The fθ lens 1115 has an image height proportional to the incident angle of light from the polygon mirror 1114, and moves the image surface of light deflected by the polygon mirror 1114 at a constant angular velocity with constant speed in the main scanning direction. The toroidal lens 1116 forms an image of the light from the fθ lens 1115 on the surface of the photosensitive drum 1030 via the mirror 1118.

  The toroidal lens 1116 is disposed on the optical path of the light beam through the fθ lens 1115. Then, the light beam that has passed through the toroidal lens 1116 is irradiated onto the surface of the photosensitive drum 1030 to form a light spot. This light spot moves in the longitudinal direction of the photosensitive drum 1030 as the polygon mirror 1114 rotates. That is, the photoconductor drum 1030 is scanned. The moving direction of the light spot at this time is the “main scanning direction”. The rotation direction of the photosensitive drum 1030 is the “sub-scanning direction”.

  The optical system arranged on the optical path between the polygon mirror 1114 and the photosensitive drum 1030 is also called a scanning optical system. In this embodiment, the scanning optical system includes an fθ lens 1115 and a toroidal lens 1116. Note that at least one folding mirror may be disposed on at least one of the optical path between the fθ lens 1115 and the toroidal lens 1116 and on the optical path between the toroidal lens 1116 and the photosensitive drum 1030.

  Since the laser printer 1000 according to the present embodiment uses the surface emitting laser module according to the first embodiment, the laser printer 1000 can perform printing without decreasing the printing speed even if the writing dot density increases. it can. Further, when the writing dot density is the same, the printing speed can be further increased.

  In this case, since the polarization directions of the light beams from the respective light emitting units are stably aligned, the laser printer 1000 can stably form a high-quality image.

  In the description of the present embodiment, the case of the laser printer 1000 as the image forming apparatus has been described. However, the present invention is not limited to this.

  For example, an image forming apparatus that directly irradiates laser light onto a medium (for example, paper) that develops color with laser light may be used.

  Further, an image forming apparatus using a silver salt film as the image carrier may be used. In this case, a latent image is formed on the silver salt film by optical scanning, and this latent image can be visualized by a process equivalent to a developing process in a normal silver salt photographic process. Then, it can be transferred to photographic paper by a process equivalent to a printing process in a normal silver salt photographic process. Such an image forming apparatus can be implemented as an optical plate making apparatus or an optical drawing apparatus that draws a CT scan image or the like.

[Third Embodiment]
Next, a third embodiment will be described. The third embodiment is a color printer 2000 including a plurality of photosensitive drums.

  A color printer 2000 according to the present embodiment will be described with reference to FIG. The color printer 2000 in the present embodiment is a tandem multicolor printer that forms a full-color image by superimposing four colors (black, cyan, magenta, and yellow). “Charging device K2, developing device K4, cleaning unit K5, and transfer device K6”, “photosensitive drum C1, charging device C2, developing device C4, cleaning unit C5, and transfer device C6” for cyan, and magenta “Photosensitive drum M1, charging device M2, developing device M4, cleaning unit M5, and transfer device M6” and yellow “photosensitive drum Y1, charging device Y2, developing device Y4, cleaning unit Y5, and transfer device Y6” ”, Optical scanning device 2010, transfer belt 2080, fixing unit 2030, and the like. It has a.

  Each photoconductor drum rotates in the direction of the arrow shown in FIG. 18, and a charging device, a developing device, a transfer device, and a cleaning unit are arranged around each photoconductor drum in the order of rotation. Each charging device uniformly charges the surface of the corresponding photosensitive drum. The surface of each photoconductive drum charged by the charging device is irradiated with light by the optical scanning device 2010, and a latent image is formed on each photoconductive drum. Then, a toner image is formed on the surface of each photosensitive drum by a corresponding developing device. Further, the toner image of each color is transferred onto the recording paper on the transfer belt 2080 by the corresponding transfer device, and finally the image is fixed on the recording paper by the fixing unit 2030.

  The optical scanning device 2010 has a light source unit including the surface emitting laser module in the first embodiment for each color, and has the same effect as the optical scanning device 1010 described in the second embodiment. Can be obtained. In addition, since the color printer 2000 includes the optical scanning device 2010, it is possible to obtain the same effect as the laser printer 1000 in the second embodiment.

  By the way, in the color printer 2000, color misregistration may occur due to manufacturing error or position error of each component. Even in such a case, since each light source of the optical scanning device 2010 is formed by the light source unit including the surface emitting laser module in the first embodiment, color misregistration can be achieved by selecting a light emitting unit to be lit. Can be reduced.

  Therefore, since the color printer 2000 according to the present embodiment uses the surface emitting laser module according to the first embodiment, a high-quality image can be formed.

  As mentioned above, although the form which concerns on implementation of this invention was demonstrated, the said content does not limit the content of invention.

DESCRIPTION OF SYMBOLS 10 Surface emitting laser element 11 Light emitting area 20 Aperture part 21 Aperture part 22 Aperture main body part 23 Light receiving element 24 Electrode terminal 30 Write control part 40 Light spot 41 Arithmetic circuit 80 Package 100 Surface emitting laser module 1000 Laser printer (image forming apparatus)
1010 Optical scanning device 2000 Color printer (image forming apparatus)

JP-A-8-330661 JP 2007-298563 A JP-A-10-303513 Japanese Patent Application Laid-Open No. 6-309685

Claims (13)

A surface emitting laser element in which a surface emitting laser is formed on a substrate;
A package for installing the surface-emitting laser element;
An aperture provided on the emission side of the surface emitting laser;
The aperture section has an opening through which the light of the surface emitting laser passes, and a light receiving element formed in a region where the opening is not provided,
The opening, der those formed in a rectangular shape,
The light receiving element is divided into two or more,
The surface emitting laser module characterized that you have an arithmetic circuit for calculating a difference signal or difference signal in the divided light receiving element 2 or more and the sum signal. The surface emitting laser module according to claim 1, characterized in that it comprises a position adjusting unit for adjusting the surface emitting laser element, and said aperture portion. Surface-emitting laser module according to claim 1 or 2, wherein the light receiving element is characterized in that the structure in which the lower electrode and the semiconductor layer and the upper electrode are laminated. 4. The surface emitting laser module according to claim 3 , wherein one of the lower electrode and the upper electrode, and both the lower electrode and the upper electrode are made of a metal material. The surface emitting laser module according to claim 4 , wherein the metal material is chromium. The surface emitting laser module is used as a light source for optical scanning,
6. The surface according to claim 1, wherein either one of the main scanning direction and the sub-scanning direction is a longitudinal direction of the rectangle in the opening. Light emitting laser module. In the aperture portion, the light receiving element is formed on one surface of a substrate that does not transmit the light in which the opening is formed,
7. The surface emitting laser module according to claim 1, wherein the one surface is a surface facing the surface emitting laser element. The aperture section has the light receiving element formed on a transparent substrate,
The surface emitting laser module according to claim 1, wherein the opening is formed by a region where the light receiving element is not formed. 9. The surface emitting laser module according to claim 8, wherein the aperture portion is installed at an angle inclined with respect to an emission surface of the surface emitting laser element. The surface emitting laser module according to any one of claims 1 to 9 , wherein the surface emitting laser element includes a plurality of the surface emitting lasers formed in an array. An optical scanning device that scans a surface to be scanned with light,
A light source having a surface-emitting laser module according to any of claims 1 to 10,
A light deflector for deflecting light from the light source;
A scanning optical system for condensing the light deflected by the light deflection unit on the surface to be scanned;
An optical scanning device comprising: An image carrier;
The optical scanning device according to claim 11 , wherein the image carrier is scanned with light modulated according to image information;
An image forming apparatus comprising: The image forming apparatus according to claim 12 , wherein there are a plurality of image carriers, and the image information is multicolor color information.

Images