JP2012019038A - Surface-emitting laser module, optical scanner and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-emitting laser module capable of monitoring light quantity without deterioration of utilization efficiency of light.SOLUTION: A surface-emitting laser module includes: a surface-emitting laser element in which a surface emitting laser is formed on a substrate; a base part for mounting the surface-emitting laser element; a cap part joined on a side of the base part, the side on which the surface emitting laser element is mounted; a reflection part provided in the cap part and reflecting a portion of light emitted from the surface-emitting laser; an emission window provided on the cap part and transmitting light except the light reflected by the reflection part out of the light emitted from the surface-emitting laser; and a light-receiving element mounted on the base part and receiving the light reflected by the reflection part out of the light emitted from the surface emitting laser.

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.

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

  Further, Patent Document 2 discloses a method in which a beam splitter is disposed on the emission surface side of a surface emitting laser, light emitted from the surface emitting laser is branched by the beam splitter, and is detected by a photodetector as monitor light. ing.

  In Patent Document 3, after the emitted laser light is collimated by a collimating lens, a reflecting mirror having an opening is arranged to separate ambient light and central light and pass through the opening of the reflecting mirror. There has been disclosed a method in which the center light is used for image formation and the ambient light reflected by a reflecting mirror is received by a photodiode and used for a light amount monitor.

  Further, in Patent Document 4, a reflecting mirror having an opening is arranged before the emitted laser light is converted into parallel light by a collimating lens to separate the peripheral light and the central light, and the opening of the reflecting mirror is formed. A method is disclosed in which the center light that has passed is converted into parallel light by a collimating lens, used for image formation, etc., and ambient light reflected by a reflecting mirror is received by a photodiode and used for a light amount monitor.

  Patent Documents 5 and 6 disclose a device in which a light receiving element is disposed in a window of a package and the amount of ambient light of the emitted laser light is monitored.

  However, in the methods described in Patent Documents 1 and 2, when an optical member such as a beam splitter or a half mirror is arranged in the optical system, the amount of light reflected by the optical member reaches the photosensitive member of the image forming apparatus. Therefore, it is necessary to increase the light output of the surface emitting laser as a light source.

  In addition, the methods described in Patent Documents 3 and 4 are methods for separating laser light outside the package in which the surface emitting laser elements are installed, and thus are limited in the arrangement and shape of the light receiving elements that monitor the light quantity. Will occur. For example, a separate substrate or the like may be required for installing the light receiving element, or an optical component or the like may be required. In addition, since the amount of light per unit area decreases as the distance from the surface emitting laser increases, an optical member for concentrating the monitor light on the light receiving element or a large area light receiving element is required. However, there is a problem that the response speed with respect to the change in the amount of light decreases as the value of the value increases. Furthermore, an optical member for making light incident on the light receiving element and an optical member for condensing light have a problem that position adjustment for making monitor light incident on the light receiving element is necessary.

  In Patent Documents 5 and 6, it is not possible to sufficiently cope with the case of using a one-dimensional array or a two-dimensional surface emitting laser, and the shape of the light beam from each surface emitting laser is different. It has the problem of becoming a thing.

  Therefore, the present invention has been made in view of the above, and an object thereof is to provide a surface emitting laser module that is small in size, low in cost, and capable of monitoring the amount of light without deteriorating the utilization efficiency of light used. It is another 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 base part for installing the surface emitting laser element, and a side where the surface emitting laser element is installed in the base part A cap portion joined to the surface, a reflection portion that is provided on the cap portion and reflects a part of light emitted from the surface emitting laser, and a light that is provided on the cap portion and emitted from the surface emitting laser. Among these, an exit window that transmits light excluding the light reflected by the reflecting portion, and light reflected from the reflecting portion of the light emitted from the surface-emitting laser installed in the base portion is received. And a light receiving element.

  According to the present invention, the surface-emitting laser element has a one-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers, and the reflection unit includes the plurality of surface-emitting lasers arranged. It is characterized by being installed substantially parallel to the direction in which it is located.

  In the present invention, the surface-emitting laser element has a one-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers, and the light-receiving element has a longitudinal direction of the light-receiving element, The plurality of surface emitting lasers are installed so as to be substantially parallel to the direction in which the plurality of surface emitting lasers are arranged.

  In the present invention, the surface-emitting laser element has a two-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers, and the reflection unit includes the plurality of surface-emitting lasers arranged. It is characterized by being installed substantially parallel to the direction in which it is located.

  Further, in the present invention, the surface emitting laser element has a two-dimensional surface emitting laser array formed by a plurality of surface emitting lasers, and the light receiving element has a longitudinal direction of the light receiving element, The plurality of surface emitting lasers are installed so as to be substantially parallel to the direction in which the plurality of surface emitting lasers are arranged.

  Moreover, the present invention is characterized in that the reflecting portion has a concave surface.

  Further, the present invention is characterized in that a plurality of the reflecting portions are provided.

  Further, the present invention is characterized in that a plurality of the light receiving elements are provided.

  Further, the present invention is characterized in that the reflection portion or the support portion for supporting the reflection portion and fixing to the cap portion has a beam shaping function.

  Further, according to the present invention, the reflecting portion is fixed to the cap portion by a supporting portion that supports the reflecting portion, and the supporting portion, the cap portion, and the emission window are integrally formed. It is characterized by being.

  Further, the present invention is characterized in that the reflection portion is formed in a part of the exit window.

  In the invention, it is preferable that the reflectance of the reflecting portion is 90% or more.

  Further, the present invention shields a region including the surface-emitting laser module described above, a collimating lens that collimates light emitted from the surface-emitting laser module, and a region that is blocked by the reflecting portion, An aperture that transmits only the center light out of the emitted light, a light deflector that deflects light that has passed through the aperture, and scanning optics that condenses the light deflected by the light deflector on the surface to be scanned And a system.

  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 is small in size, low in cost, and capable of monitoring the amount of light without reducing the utilization efficiency of the light used. An optical scanning device and an image forming apparatus that can form a high-quality image can be provided.

The perspective view of the surface emitting laser module in 1st Embodiment The top view of the surface emitting laser module in 1st Embodiment Sectional drawing of the surface emitting laser module in 1st Embodiment Explanatory drawing (1) of the other surface emitting laser module in 1st Embodiment Explanatory drawing (2) of the other surface emitting laser module in 1st Embodiment Explanatory drawing (3) of the other surface emitting laser module in 1st Embodiment Explanatory drawing (4) of the other surface emitting laser module in 1st Embodiment Explanatory drawing of the other surface emitting laser module in 1st Embodiment (5) Explanatory drawing of other reflection parts and support parts Configuration of drive circuit for surface emitting laser module (1) Top view of surface emitting laser module according to the second embodiment Sectional drawing (1) of the surface emitting laser module in 2nd Embodiment Sectional drawing (2) of the surface emitting laser module in 2nd Embodiment Explanatory drawing of the other surface emitting laser module in 2nd Embodiment Configuration of drive circuit for surface emitting laser module (2) Top view of the surface emitting laser module according to the third embodiment Top view of 2D surface emitting laser array Sectional drawing (1) of the surface emitting laser module in 3rd Embodiment Sectional drawing (2) of the surface emitting laser module in 3rd Embodiment Sectional drawing (3) of the surface emitting laser module in 3rd Embodiment Correlation diagram between aperture and light receiving element output Configuration diagram of laser printer in fourth embodiment Configuration of Optical Scanning Device in Fourth Embodiment Explanatory drawing of optical scanning device (1) Explanatory drawing of optical scanning device (2) Explanatory drawing of optical scanning device (3) The block diagram of the color printer in 5th 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. As shown in FIG. 1, the surface emitting laser module according to the present embodiment includes a surface emitting laser element and a light receiving element installed in a package including a base portion 21 and a cap portion 22. The base portion 21 and the cap portion 22 are made of metal, and electrodes 31, 32, and 33 are provided on the base portion 21. The electrode 31 is connected to the surface emitting laser element in the package, the electrode 32 is connected to the light receiving element in the package, and the electrode 33 is directly connected to the base portion 21. Further, an exit window 23 made of glass or the like is provided on the upper surface of the cap portion 22, and the exit window 23 is joined to the cap portion 22 by a low melting point glass or the like to form a hermetic seal.

  FIG. 2 is a top transparent view of the surface emitting laser module according to the present embodiment, and FIG. 3 is a cross-sectional view taken along a broken line 2A-2B in FIG. Inside the package, the surface emitting laser element 10 is installed in the base portion 21 and is connected to the electrode 31 by a bonding wire 34. A light receiving element 40 is installed on the base portion 21 and is connected to the electrode 32 by a bonding wire 35. The electrode 31 and the base portion 21 are insulated by an insulator portion 36 provided around the electrode 31. Similarly, the electrode 32 and the base portion 21 are provided around the electrode 32. It is insulated by the insulator portion 37.

  A reflection portion 24 made of a mirror or the like is provided inside the emission window 23 in the cap portion 22, and is fixed to the inside of the cap portion 22 by a support member 25. The reflection part 24 is formed of a metal having a reflectance of 90% or more, or a dielectric multilayer mirror, for light having a wavelength emitted from the surface emitting laser element 10. A higher reflectance of the reflecting portion 24 is preferable because the amount of light incident on the light receiving element 40 can be increased and there are few problems such as heat generation. In view of these, the reflection portion is 90% or more empirically. Preferably there is.

  The surface emitting laser element 10 and the light receiving element 40 are fixed to the base portion 21 with a conductive adhesive.

  A surface emitting laser 12 is formed in the surface emitting laser element 10. The surface emitting laser element 10 has a bonding pad 13 connected to an anode serving as an upper electrode of the surface emitting laser element 10, and the electrode 31 and the bonding pad 13 are connected by a bonding wire 34. Moreover, the cathode which becomes the lower electrode of the surface emitting laser 10 is electrically connected to the base portion 21 by the conductive adhesive as described above.

  In addition, a photodiode is used for the light receiving element 40, and a light receiving region 42 for receiving light is formed. The light receiving element 40 has a bonding pad 43 connected to a cathode that is an upper electrode of the light receiving element 40, and the electrode 32 and the bonding pad 43 are connected by a bonding wire 35. Further, the anode serving as the lower electrode of the light receiving element 40 is electrically connected to the base portion 21 by the conductive adhesive as described above.

  In the surface emitting laser module according to the present embodiment, the light emitted from the surface emitting laser 12 of the surface emitting laser element 10 travels toward the exit window 23 while diffusing, and includes central light that travels straight by the reflecting portion 24. The transmitted light 101 and the reflected light 102 including a part of the ambient light reflected by the reflecting unit 24 are separated. The reflected light 102 reflected by the reflecting unit 24 enters the light receiving region 42 of the light receiving element 40, and the amount of the reflected light 102 reflected by the reflecting unit 24 can be measured. The transmitted light 101 that travels straight passes through the exit window 23 and travels straight.

  Thereby, in the present embodiment, it is possible to monitor a part of the ambient light out of the light emitted from the surface emitting laser element 10, and to reduce the surface light without attenuating the central light used for applications such as image formation. The amount of light from the light emitting laser element 10 can be monitored.

(Modification of surface emitting laser module)
Next, a modified example of the surface emitting laser module in the present embodiment will be described.

  The surface-emitting laser module shown in FIG. 4 has a structure in which a reflecting portion is formed by a concave mirror. Specifically, the reflecting portion 24a is formed by a concave mirror, and is attached to the cap portion 22 by a support portion 25a. By forming the reflecting portion 24a with a concave mirror, the reflected light 102a collected on the light receiving element 40 is irradiated, so that ambient light can be used efficiently without scattering light inside the package. Thus, the light receiving element 40 can be made smaller.

  The surface emitting laser module shown in FIG. 5 has a structure in which a reflecting portion 24 b is provided in addition to the reflecting portion 24. Specifically, in addition to the reflection portion 24, a reflection portion 24b is provided, and the reflection portion 24b is structured to be attached to the cap portion 22 by a support portion 25b. Of the light emitted from the surface emitting laser 12 in the surface emitting laser element 10, a part of the ambient light is reflected by the reflecting portion 24b and enters the light receiving element 40 as reflected light 102b. For this reason, the reflected light 102 reflected by the reflecting portion 24 and the reflected light 102 b reflected by the reflecting portion 24 b enter the light receiving element 40. Therefore, the amount of light incident on the light receiving element 40 can be increased. The transmitted light 101b that travels straight is light from which a part of the ambient light is further removed, but the central light is not attenuated, so that there is no practical problem.

  The surface emitting laser module shown in FIG. 6 has a structure in which an emission window, a support portion, and a cap portion are integrally formed. By integrally forming in this way, the structure can be simplified, the number of parts can be reduced, and the manufacturing cost of the surface emitting laser module can be reduced. Specifically, a resin material or the like that scatters or absorbs light is used for the cap portion 22c, and a resin material or the like that transmits light is used for the exit window 23c. In addition to this, the cap portion 22c and the emission window 23c are made of a material that transmits light, and the inside of the cap portion 22c other than the portion that becomes the emission window 23c and the reflection portion 24 is subjected to light shielding treatment. Thus, a structure in which the reflected light does not return to the surface emitting laser element 10 may be used.

  The surface emitting laser module shown in FIG. 7 has a configuration in which a reflecting portion 24 is installed in a part of the emission window 23. In this case, a supporting portion for supporting the reflecting portion 24 is not necessary. Specifically, there are a structure in which a reflection plate to be the reflection portion 24 is bonded to a part of the emission window 23, a structure in which a reflection film to be the reflection portion 24 is formed on a part of the emission window 23, and the like. . Thereby, the structure can be simplified, the number of parts can be reduced, and the manufacturing cost of the surface emitting laser module can be reduced.

  The surface emitting laser module shown in FIG. 8 has a beam shaping function (function as an aperture) for beam shaping light from the surface emitting laser element 10 in the support portion 25d. 8A is a top view, and FIG. 8B is a cross-sectional view taken along a broken line 8A-8B in FIG. 8A. Specifically, among the light emitted from the surface emitting laser 12 in the surface emitting laser element 10, the ambient light is absorbed or reflected by the support portion 25d or the reflecting portion 24, and therefore only the transmitted light 101d including the central light is emitted. The window 23 can be transmitted. Since this transmitted light 101d is a beam-shaped light, it is not necessary to separately provide parts for beam shaping, the structure can be simplified, and the number of parts can be reduced. The manufacturing cost can be reduced.

  Further, as shown in FIG. 9A, the support portion 25e may be inclined with respect to the normal direction of the surface of the exit window 23, and as shown in FIG. 9B. The positions of the support part 25 and the reflection part 24 may be shifted. Thereby, the light of the area | region close | similar to peripheral light among the center light which injects from diagonally can be permeate | transmitted, without interrupting | blocking.

  Among the surface emitting laser modules described above, except for the surface emitting laser module having the structure shown in FIG. 6, as described above, the base portion 21 and the cap portion 22 are each formed of a metal material and welded. The exit window 23 is made of glass, and is joined to the cap portion 23 by low melting point glass. However, the base portion 21 and the cap portion 22 may be formed of a material other than metal, and the base portion 21 and the cap portion 22 may be joined by a method other than welding. The exit window 23 and the cap portion 22 may be joined by a method other than the joining with the low melting point glass.

  Further, in the surface emitting laser element 10, an antireflection film is formed on the front surface and the back surface of the emission window 23 in order to prevent the light emitted from the surface emission laser from being reflected by the emission window 23 and entering the return light. Preferably, the interior of the base portion 21 and the cap portion 22 except for the exit window 23 and the reflection portion 24 is subjected to a surface treatment such as matte coating or formation of a light absorption layer in order to prevent stray light. It is preferable that preventive measures are taken.

(Control of surface emitting laser module)
Next, control of the surface emitting laser module according to the present embodiment will be described. FIG. 10 shows a drive circuit of the surface emitting laser module 100 in the present embodiment. This drive circuit is mounted on the circuit board 80 together with the surface emitting laser module 100, and includes a VCSEL drive circuit 81, a control circuit 82, a power supply circuit (not shown), and an interface circuit with the outside. As described above, the surface emitting laser module 100 includes the surface emitting laser element 10 and the photodiode that is the light receiving element 40. The anode electrode of the surface emitting laser element 10 is connected to the VCSEL drive circuit 81 via the electrode 31, and the cathode electrode of the light receiving element 40 is connected to the control circuit 82 via the electrode 32. Further, both the cathode electrode of the surface emitting laser element 10 and the anode electrode of the light receiving element 40 are grounded via the electrode 33.

  The surface emitting laser in the surface emitting laser element 10 is turned on in accordance with the current output from the VCSEL drive circuit 81, and the current passed to the surface emitting laser element 10 by the VCSEL drive circuit 81 is based on a signal from the control circuit 82. Washed away. In the control circuit 82, the surface emitting laser lighting time in the surface emitting laser element 10 and the amount of light at the time of lighting are controlled. In the image forming apparatus using the surface emitting laser element 10, the control circuit 82 divides the time into image formation on the photosensitive drum and other adjustment time and repeats each operation at a constant cycle. The time for adjustment and the like is further divided for various adjustments, and includes the time for stabilizing the light amount.

  At the time of image formation, the control circuit 82 outputs a timing signal for blinking the surface emitting laser 10 to the VCSEL drive circuit 81 based on an external image formation signal. The light amount setting signal is kept constant during image formation.

  The control circuit 82 outputs a timing signal for continuously lighting the surface emitting laser 10 to the VCSEL drive circuit 81 when stabilizing the light amount. The light amount setting signal is adjusted based on an output signal from the light receiving element 40 by receiving a part of the light emitted from the surface emitting laser element 10 by the light receiving element 40.

[Second Embodiment]
Next, a second embodiment will be described. The surface emitting laser module in the present embodiment has a structure in which a one-dimensional surface emitting laser array is formed on a surface emitting laser element.

  FIG. 11 is a top view of the surface emitting laser module according to the present embodiment. 12 is a cross-sectional view taken along the broken line 11A-11B in FIG. 11, and FIG. 13 is a cross-sectional view taken along the broken line 11C-11D in FIG. FIG. 13A shows a state in which light is emitted from the surface emitting laser 112a, and FIG. 13B shows a state in which light is emitted from the surface emitting laser 112d.

  In the surface emitting laser module according to the present embodiment, the base portion 121, the cap portion 122, and the exit window 123 in the first embodiment are formed except that the base portion 121, the cap portion 122, and the exit window 123 are formed in an oval shape. 23, except that the reflecting portion 124, the supporting portion 125, the light receiving element 140, and the light receiving region 142 are different in shape and the like, the reflecting portion 24, the supporting portion 25, and the light receiving element in the first embodiment. 40 and the light receiving region 42. Note that bonding wires, bonding pads, and the like are omitted.

  The surface emitting laser element 110 is formed with a one-dimensional surface emitting laser array, and the surface emitting lasers are arranged one-dimensionally. Specifically, the surface emitting laser element 110 includes surface emitting lasers 112a, 112b, 112c and 112d which are surface emitting lasers.

  In the light emitted from the surface emitting lasers 112 a, 112 b, 112 c and 112 d of the surface emitting laser element 110, the transmitted light 101 including the central light is transmitted through the emission window 123, and a part of the ambient light is reflected by the reflecting portion 124. The reflected light 102 is obtained. The light emitted from the surface emitting lasers 112a, 112b, 112c, and 112d of the surface emitting laser element 110 is reflected by the reflecting portion 124 and enters the light receiving area 142 of the light receiving element 140. Therefore, the light receiving area 142 of the light receiving element 140 is The surface-emitting laser element 110 is formed long along the direction in which the surface-emitting lasers 112a, 112b, 112c and 112d are arranged. That is, the light receiving element 140 is formed in a substantially rectangular shape, and is arranged so that the longitudinal direction of the light receiving element 140 is substantially parallel to the arrangement direction of the surface emitting lasers 112a, 112b, 112c and 112d of the surface emitting laser element 110. Has been. In addition, the reflection unit 124 includes the surface emitting lasers 112a, 112a, 112c of the surface emitting laser element 110 so that the light emitted from the surface emitting lasers 112a, 112b, 112c, and 112d of the surface emitting laser element 110 efficiently enters the light receiving element 140. It is installed so as to be substantially parallel to the arrangement direction of 112b, 112c and 112d.

  Further, as shown in FIG. 14, by forming the reflecting portion 124a in a concave shape, the length of the light receiving element 140a can be shortened, and a small light receiving element can be used. 14A shows a state in which light is emitted from the surface emitting laser 112a, and FIG. 14B shows a state in which light is emitted from the surface emitting laser 112d. As shown in FIG. 14, the light emitted from the surface emitting lasers 112a, 112b, 112c, and 112d of the surface emitting laser element 110 is reflected by the concave reflecting portion 124a supported by the supporting portion 125a and is reflected in the central portion. Since the light is condensed, the light receiving region can be narrowed, and thus the light receiving element 140 can be downsized. Note that the surface where the light emitting points of the surface emitting lasers 112a, 112b, 112c and 112d are formed and the light receiving surface of the light receiving element 140a do not have to be formed on the same plane.

(Control of surface emitting laser module)
Next, control of the surface emitting laser module according to the present embodiment will be described. FIG. 15 shows a drive circuit of the surface emitting laser module 200 in the present embodiment. This drive circuit is mounted on the circuit board 180 together with the surface emitting laser module 200, and is configured by a VCSEL drive circuit 181 and a control circuit 182, a power supply circuit (not shown), and an interface circuit with the outside. As described above, the surface emitting laser module 200 includes the surface emitting laser element 110 and the photodiode that is the light receiving element 140. The surface emitting laser element 110 is provided with four surface emitting lasers 112a, 112b, 112c and 112d. The anode electrodes of the surface emitting lasers 112a, 112b, 112c, and 112d are connected to the VCSEL driving circuit 181 through the electrodes 131a, 131b, 131c, and 131d, and the cathode electrode of the light receiving element 140 is connected to the control circuit 182 through the electrode 132. It is connected to the. Further, the cathode electrodes of the surface emitting lasers 112 a, 112 b, 112 c and 112 d and the anode electrode of the light receiving element 140 are all grounded via the electrode 133.

  The anode electrode such as the light receiving element 140 may be connected to the common cathode electrode of the surface emitting laser element 110, or may be either electrically insulated and then connected to individual electrodes. However, when the driving current of the surface emitting laser element 110 is large, the current flowing from the common cathode electrode of the surface emitting laser element 140 to GND (ground) increases. Can be reduced.

  The surface emitting lasers 112a, 112b, 112c and 112d in the surface emitting laser element 110 are turned on according to the current output from the VCSEL driving circuit 181 and are sent to the surface emitting lasers 112a, 112b, 112c and 112d by the VCSEL driving circuit 181. The current to be supplied is supplied based on a signal from the control circuit 182. The control circuit 182 controls the time during which the surface emitting laser in the surface emitting laser element 110 is turned on and the amount of light at the time of lighting. In the image forming apparatus, the control circuit 182 divides the time into image formation on the photosensitive drum and the other adjustment time and repeats each operation at a constant cycle. The time for adjustment and the like is further divided for various adjustments, and includes the time for stabilizing the light amount.

  At the time of image formation, the control circuit 182 outputs a timing signal for blinking the surface emitting laser 110 to the VCSEL drive circuit 181 based on an external image formation signal. The light amount setting signal is kept constant during image formation.

  The control circuit 182 outputs a timing signal for continuously lighting one of the surface emitting lasers 112a, 112b, 112c, and 112d to the VCSEL driving circuit 181 when stabilizing the light amount. The light amount setting signal is adjusted based on an output signal from the light receiving element 140 by receiving a part of light emitted from one of the surface emitting lasers 112 a, 112 b, 112 c and 112 d by the light receiving element 140.

  Specifically, image formation → surface emission laser 112a light quantity stabilization → image formation → surface emission laser 112b light quantity stabilization → image formation → surface emission laser 112c light quantity stabilization → image formation → surface emission laser 112d light quantity stabilization → image By repeating in the order of formation, the amount of light can be adjusted at the same time interval for the surface emitting lasers 112a, 112b, 112c, and 112d. As shown in Patent Document 1, the amount of light in the surface emitting laser array can be adjusted. In order to monitor this, it is necessary to provide a monitoring optical system and a light receiving element. However, in the surface emitting laser module in the present embodiment, it can be performed by at least one light receiving element.

  The contents other than the above are the same as in the first embodiment.

[Third Embodiment]
Next, a third embodiment will be described. The surface emitting laser module in the present embodiment has a structure in which a two-dimensional surface emitting laser array is formed on a surface emitting laser element.

  FIG. 16 is a top view of the surface emitting laser module according to the present embodiment. The surface emitting laser element 210 is formed with a two-dimensional surface emitting laser array, and the surface emitting lasers are two-dimensionally arranged. Specifically, as shown in FIG. 17, the surface emitting laser element 210 includes two-dimensionally arranged surface emitting lasers 212aa, 212ba, 212ca, 212da, 212ab, 212bb, 212cb, 212db, 212ac, 212bc, 212cc. , 212dc, 212ad, 212bd, 212cd, and 212dd.

  18 and 19 are cross-sectional views taken along broken lines 16A-16B in FIG. 16, and FIG. 18 (a) shows a state in which light is emitted from the surface emitting lasers 212aa to 212da. FIG. 18B shows a state where light is emitted from the surface emitting lasers 212ab to 212db, and FIG. 19A shows a state where light is emitted from the surface emitting lasers 212ac to 212dc. FIG. 19B shows a state in which light is emitted from the surface emitting lasers 212ad to 212dd. 20 is a cross-sectional view taken along the broken line 16C-16D in FIG. 16, and FIG. 20 (a) shows a state in which light is emitted from the surface emitting laser 212ad, and FIG. 20 (b). Shows a state in which light is emitted from the surface emitting laser 212dd.

  In the surface emitting laser module according to the present embodiment, the base portion 21, the cap portion 22 and the emission window in the first embodiment are formed except that the base portion 221, the cap portion 222 and the emission window 223 are formed in a substantially square shape. 23, and the reflection portions 224a and 224b and the support portion 225 are the same as the reflection portion 24 and the support portion 25 in the first embodiment except for the shape and the like. In this embodiment, two light receiving elements 240a and 240b are arranged, and each of the light receiving elements 240a and 240b has light receiving regions 242a and 242b. The light receiving elements 240a and 240b and the light receiving areas 242a and 242b are the same as the light receiving element 40 and the light receiving area 42 in the first embodiment except for the shape and the like. Also, the bonding wires and bonding pads are omitted.

  In the surface emitting laser module in the present embodiment, the light receiving elements 240a and 240b are both formed in a substantially rectangular shape, and the longitudinal direction of the light receiving element 240a is the surface emitting lasers 212aa, 212ba, and 212ca of the surface emitting laser element 210. Are arranged so as to be substantially parallel to the arrangement direction of 212da and 212da, and the longitudinal direction of the light receiving element 240b is substantially parallel to the arrangement direction of the surface emitting lasers 212ad, 212bd, 212cd, and 212dd of the surface emitting laser element 210. Is arranged. Further, the reflecting portion 224a is substantially the same as the arrangement direction of the surface emitting lasers 212aa, 212ba, 212ca, and 212da of the surface emitting laser element 210 so that the light emitted from the surface emitting laser element 210 efficiently enters the light receiving elements 240a and 240b. The reflecting portion 224d is arranged in parallel to each other, and the reflecting portion 224d is arranged with the arrangement direction of the surface emitting lasers 212ad, 212bd, 212cd, and 212dd of the surface emitting laser element 210 (the arrangement direction of the surface emitting lasers 212aa, 212ba, 212ca, and 212da). It is installed so as to be substantially parallel.

  In the surface emitting laser module according to the present embodiment, the light emitted from the surface emitting laser element 210 is reflected by the two reflecting portions 224a and 224b, but the positions where the respective surface emitting lasers are arranged are different. For this reason, as shown in FIG. 21, the amounts of light incident on the light receiving elements 240a and 240b are different, and the output values of the light receiving elements 240a and 240b are also different. However, when all the surface emitting lasers in the surface emitting laser element 210 emit light, the amount of light emitted from each of the surface emitting lasers is integrated, so that the amount of light incident on the light receiving elements 240a and 240b is substantially uniform. It will be something.

  In addition, as with the second embodiment, since the reflecting portions 224a and 224b can condense light by making the reflecting portions concave, it is possible to reduce the size of the light receiving elements 240a and 240b. It is.

  The contents other than those described above are the same as those in the first embodiment or the second embodiment.

[Fourth Embodiment]
Next, a fourth embodiment will be described. The present embodiment is a laser printer 1000 as an image forming apparatus using the surface emitting laser module according to any one of the first to third embodiments.

  Based on FIG. 22, a laser printer 1000 in the present embodiment will be described. 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 near 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 collectively includes a light source unit 1100, a coupling lens 1111, an aperture 1112, 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 is provided. As the light source unit 1100, the light source unit 1100 including the surface emitting laser module according to any one of the first to third embodiments is used.

  The coupling lens 1111 shapes the light beam emitted from the light source unit 1100 into parallel light. The aperture 1112 defines the beam diameter of the light beam that has passed through the coupling lens 1111, and is wider than the center light emitted from the surface emitting laser element 10, including a range reflected by the reflecting portion 24 and the like. Blocks ambient light in the range and allows only central light in a narrower range to pass.

  Here, the change in the shape of the light beam from the light source unit 1100 until it passes through the aperture 1112 will be described with reference to FIGS. FIG. 25 shows a beam shape of light emitted from the surface emitting laser element.

  FIG. 25A shows a cross section taken along one-dot chain line 24A1-24A2 in FIG. As shown in this figure, the light spreads equally in all directions. Next, FIG. 25B shows a cross section taken along one-dot chain line 24B1-24B2 in FIG. As shown in this figure, since a part of the ambient light is blocked by the reflecting portion, the light beam has a shape in which light is blocked in the region 401. The light further spreads, then enters the coupling lens 1111, becomes parallel light, and enters the aperture 1112. Next, FIG. 25C illustrates a cross section taken along one-dot chain line 24C1-24C2 in FIG. As shown in this figure, the light before entering the aperture 1112 passes through the coupling lens 1111 and becomes an inverted image of the shape shown in FIG. Next, FIG. 25D shows a cross section taken along one-dot chain line 24D1-24D2 in FIG. As shown in this figure, since the aperture 1112 further blocks a part of the ambient light, a light beam having a shape in which light is blocked in the region 402 is obtained. Since the region 402 blocked by the aperture 1112 is wide and includes the region 401, the light 400 passing through the aperture 1112 is only the center light of the narrow region. When the surface emitting laser formed on the surface emitting laser element is a one-dimensional or two-dimensional array, the aperture 1112 is installed in the vicinity of the focal length of the coupling lens 1111 with respect to all the light emitting points. The same range of light can be passed. Note that the sizes in FIGS. 25A to 25D are aligned for explanation. The light beam that has passed through the aperture 1112 further enters the cylindrical lens 1113.

  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 any one of the first to third embodiments, the laser printer 1000 reduces the printing speed even if the writing dot density increases. Can be printed without any problems. Further, when the writing dot density is the same, the printing speed can be further increased.

  As shown in FIG. 26, in the VCSEL array LA in the surface emitting laser element, each surface emitting laser element in the direction corresponding to the sub-scanning direction when a perpendicular is drawn from the center of each VCSEL in the direction corresponding to the sub-scanning direction. Since the positional relationship is equal intervals (determined as interval d2), it is considered that the light source is arranged on the photosensitive drum 1030 at equal intervals in the sub-scanning direction by adjusting the lighting timing. Can do. For example, if the pitch d1 of the surface emitting laser elements in the direction corresponding to the sub-scanning direction is 26.5 μm, the interval d2 is 2.65 μm. If the magnification of the optical system is doubled, writing dots can be formed on the photosensitive drum 1030 at intervals of 5.3 μm in the sub-scanning direction. This corresponds to 4800 dpi (dots / inch). That is, high-density writing of 4800 dpi (dot / inch) can be performed. Of course, the density can be increased by increasing the number of VCSELs in the direction corresponding to the main scanning direction, or by arranging the array so that the pitch d1 is reduced and the interval d2 is further reduced, or the magnification of the optical system is reduced. And higher quality printing becomes possible. Note that the writing interval in the main scanning direction can be easily controlled by the lighting timing of the light source.

  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.

[Fifth Embodiment]
Next, a fifth embodiment will be described. The fifth 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 is equipped with a.

  Each photosensitive drum rotates in the direction of the arrow shown in FIG. 27, and a charging device, a developing device, a transfer device, and a cleaning unit are arranged around each photosensitive 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 any one of the first to third embodiments for each color, and the optical scanning described in the fourth embodiment. An effect similar to that of the device 1010 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 fourth 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, each light source of the optical scanning device 2010 is formed by the light source unit including the surface emitting laser module according to any one of the first to third embodiments. By selecting, color misregistration can be reduced.

  Therefore, since the color printer 2000 according to the present embodiment uses the surface emitting laser module according to any one of the first to third embodiments, 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 12 Surface emitting laser 13 Bonding pad 21 Base part 22 Cap part 23 Output window 24 Reflection part 25 Support part 31 Electrode 32 Electrode 33 Electrode 34 Bonding wire 35 Bonding wire 36 Insulator part 37 Insulator part 40 Light receiving element 42 Photosensitive area 43 Bonding pad 100 Surface emitting laser module 1000 Laser printer (image forming apparatus)
1010 Optical scanning device 2000 Color printer (image forming apparatus)

JP 2004-287085 A JP-A-8-330661 JP 2004-87816 A JP 2007-328334 A Japanese Patent Application Laid-Open No. 6-309685 JP-A-10-303513 JP 2007-298563 A

Claims (16)

A surface emitting laser element in which a surface emitting laser is formed on a substrate;
A base for installing the surface emitting laser element;
A cap portion joined to the side where the surface emitting laser element is installed in the base portion;
A reflective portion that is provided in the cap portion and reflects a part of the light emitted from the surface emitting laser;
An exit window that is provided in the cap portion and transmits light excluding the light emitted from the surface emitting laser and reflected by the reflecting portion;
A light receiving element that is installed in the base portion and receives light reflected by the reflecting portion out of the light emitted from the surface emitting laser;
A surface emitting laser module comprising: The surface-emitting laser element has a one-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers,
The surface emitting laser module according to claim 1, wherein the reflecting portion is disposed substantially parallel to a direction in which the plurality of surface emitting lasers are arranged. The surface-emitting laser element has a one-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers,
3. The surface according to claim 1, wherein the light receiving element is installed so that a longitudinal direction of the light receiving element is substantially parallel to a direction in which the plurality of surface emitting lasers are arranged. 4. Light emitting laser module. The surface-emitting laser element has a two-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers,
The surface emitting laser module according to claim 1, wherein the reflecting portion is disposed substantially parallel to a direction in which the plurality of surface emitting lasers are arranged. The surface-emitting laser element has a two-dimensional surface-emitting laser array formed by a plurality of surface-emitting lasers,
5. The surface according to claim 1, wherein the light receiving element is installed such that a longitudinal direction of the light receiving element is substantially parallel to a direction in which the plurality of surface emitting lasers are arranged. Light emitting laser module.   The surface emitting laser module according to claim 1, wherein the reflecting portion has a concave surface.   The surface emitting laser module according to claim 1, wherein a plurality of the reflecting portions are provided.   The surface emitting laser module according to claim 1, wherein a plurality of the light receiving elements are provided.   The said reflection part or the support part for supporting the said reflection part and fixing to the said cap part has a beam shaping function, The any one of Claim 1 to 8 characterized by the above-mentioned. Surface emitting laser module.   The reflection part is fixed to the cap part by a support part that supports the reflection part, and the support part, the cap part, and the emission window are integrally formed. The surface emitting laser module according to claim 1.   9. The surface emitting laser module according to claim 1, wherein the reflecting portion is formed in a part of the exit window.   The surface emitting laser module according to claim 1, wherein the reflectance of the reflecting portion is 90% or more. The surface emitting laser module according to any one of claims 1 to 12,
A collimating lens that collimates the light emitted from the surface emitting laser module;
An aperture that shields an area including an area obstructed in the reflecting portion, and transmits only central light out of the emitted light; and
An optical deflector for deflecting light that has passed through the aperture;
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 optical scanning device that scans a surface to be scanned with light,
A light source comprising the surface emitting laser module according to any one of claims 1 to 12,
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 13 or 14, wherein the optical carrier is scanned with light modulated in accordance with image information.
An image forming apparatus comprising:   The image forming apparatus according to claim 15, wherein there are a plurality of the image carriers, and the image information is multicolor color information.

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