JP2012191148A - Surface-emitting laser module, optical scanning device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-emitting laser module with a long life.SOLUTION: A surface-emitting laser module comprises a surface-emitting laser element, on the substrate face of which plural surface-emitting lasers are formed; a package for installing the surface-emitting laser element; and a window part provided on an emission side of the surface-emitting laser. The window part is formed of a material, through which light with a wavelength of the surface-emitting laser passes, and one face of the window part is formed into a pyramid-shaped projection. The other face opposed to one face is formed into a pyramid-shaped recess corresponding to the pyramid shape. An area of the window part forming the pyramid shape has a constant thickness, and one face of the window part is opposed to the surface-emitting laser element.

Description

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

  As an electrophotographic image forming apparatus, an image machine using a laser beam is widely used. An electrophotographic image forming apparatus includes an optical scanning device, and forms a latent image by rotating a drum while scanning laser light using a polygon scanner such as a polygon mirror in the axial direction of a photosensitive drum. The method is used. In such an image forming apparatus, high density recording (high density) can be performed in order to improve image quality, and high speed image output is required.

  Thus, in an electrophotographic image forming apparatus, there is a method of emitting a plurality of light beams from a light source in order to achieve both high-density recording and high speed, and a surface as a light source suitable for such a method. There is a surface emitting laser array having a configuration in which light emitting lasers (VCSEL: Vertical Cavity Surface Emitting LASER) are two-dimensionally arranged.

  However, since a surface emitting laser array has a plurality of light emitting units mounted on a single chip, the surface emitting laser becomes hot due to heat generated from the light emitting unit and the like, thereby reducing the characteristics of the surface emitting laser and shortening its life. End up. For this reason, a method for suppressing heat generation in a surface emitting laser array has been studied.

  In Patent Document 1, a lower reflector layer structure and an upper reflector layer structure are formed in this order on a semiconductor substrate, and an active layer and a current confinement layer are interposed between each reflector layer structure. The area from the layer structure to the lower layer at least to the lower end surface of the current confinement layer is a columnar mesa, and the area of the upper surface of the mesa is larger than the mesa cross-sectional area in the vicinity of the current confinement layer. A type semiconductor laser array is disclosed.

  In Patent Document 2, a hetero spike buffer layer having an intermediate valence band energy is provided between semiconductor layers having different band gap energies constituting the semiconductor distributed Bragg reflector, and the hetero spike buffer layer has a valence band energy. Is composed of a continuous or stepwise composition graded layer or a combination of these, and a region with a large change rate of valence band energy is placed on the side in contact with the layer with large band gap energy on the side in contact with the layer with small band gap energy. A surface emitting semiconductor laser array having a region with a small change rate of valence band energy is disclosed.

  Further, Patent Document 3 discloses a surface emitting laser module that suppresses a decrease in light emission characteristics of a light emitting portion due to heat generation without reducing a writing dot density by making a cover glass V-shaped.

  However, the techniques disclosed in Patent Document 1 and Patent Document 2 have a problem in that the device structure is complicated, so that a complicated process is required for manufacturing and the cost is high. is doing.

  In addition, the technique disclosed in Patent Document 3 can increase the density in one direction, but cannot meet the demand for higher density recording.

  In view of the above, the present invention has been made in view of the above, and aims to provide a surface emitting laser module capable of high-density recording at a low cost. It is an object of the present invention to provide an optical scanning apparatus and an image forming apparatus that can be formed.

  The present invention includes a surface emitting laser element in which a plurality of surface emitting lasers are formed on a substrate surface, a package for installing the surface emitting laser element, and a window portion provided on an emission side of the surface emitting laser. The window portion is formed of a material that transmits light having a wavelength of the surface-emitting laser, and one surface of the window portion is formed to be convex in a cone shape, The other surface facing one surface is formed to be concave in a conical shape corresponding to the conical shape, and the region forming the conical shape in the window portion has a constant thickness, The one surface of the window portion and the surface emitting laser element are disposed so as to face each other.

  Further, the present invention is characterized in that the cone shape is a cone shape or a quadrangular pyramid shape.

  In the present invention, the pyramid is a quadrangular pyramid, and the ridge of the quadrangular pyramid is formed so as not to overlap the surface emitting laser when viewed from a direction perpendicular to the substrate surface. It is characterized by that.

  Further, according to the present invention, the conical apex formed on one surface of the window portion is formed so as to be positioned between the surface emitting lasers when viewed from a direction perpendicular to the substrate surface. It is characterized by.

  According to the present invention, the surface-emitting laser element is such that the surface-emitting lasers are two-dimensionally arranged, and the cone-shaped apex formed on one surface of the window portion is the substrate. On the other hand, when viewed from the vertical direction, it is formed so as to be positioned approximately in the middle of the four closest surface emitting lasers.

  Further, according to the present invention, the conical apex formed on one surface of the window portion is located at the center of gravity of the region where the surface emitting laser is formed when viewed from the direction perpendicular to the substrate. It is formed as follows.

  In the surface-emitting laser element, the surface-emitting laser is disposed so that the light beams emitted from the window portion are two-dimensionally equidistant on a surface substantially parallel to the substrate surface. It is characterized by.

  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 capable of high-density recording at a low cost, and further provide an optical scanning device and an image forming apparatus capable of forming a high-quality image. be able to.

The perspective view of the surface emitting laser module in 1st Embodiment Sectional drawing of the surface emitting laser module in 1st Embodiment Enlarged view of the main part of the cross section of the window of the surface emitting laser module Explanatory drawing (1) of the shift of the light beam position by the window part of a surface emitting laser module Explanatory drawing (2) of the shift of the light beam position by the window part of a surface emitting laser module Explanatory drawing of the light beam emitted from the window of the surface emitting laser module The perspective view of the other surface emitting laser module in 1st Embodiment Explanatory drawing of shift of light beam position by window part of other surface emitting laser module Configuration diagram of laser printer in second embodiment The block diagram of the optical scanning device in 2nd Embodiment Explanatory diagram of the relationship between the emitted light flux and the main scanning direction and sub-scanning direction The block diagram of the color printer in 3rd Embodiment Configuration diagram of optical transmission system according to fourth 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 FIGS. 1 and 2, the surface emitting laser module according to the present embodiment includes a surface emitting laser element 10 in which a plurality of light emitting units 11 are two-dimensionally arranged on the surface, and a surface emitting laser element 10. A package 20 to be mounted and a window 30 for extracting light emitted from the surface emitting laser element 10 are provided.

  The surface emitting laser element 10 is installed on the bottom 21 in the package 20 so that the light emitting unit 11 is on the top, and the window 30 is joined to the opening of the package 20. The surface-emitting laser element 10 has a plurality of light emitting portions 11 made of a surface-emitting laser that emits laser light in a direction perpendicular to the surface of the substrate 12 made of a material such as a semiconductor, that is, the surface of the surface-emitting laser element 10. Such a surface emitting laser array is formed by arranging the light emitting portions 11 two-dimensionally.

  When the light emitting direction of the surface emitting laser is the + Z-axis direction, the surface of the surface emitting laser element 10, that is, the surface of the substrate 12 is a plane parallel to the XY plane. When the surface emitting laser module in the present embodiment is viewed from the light emitting direction of the surface emitting laser module, that is, the + Z-axis direction perpendicular to the surface of the substrate 12 of the surface emitting laser element 10, the window 30 and the surface emitting The laser element 10 appears to overlap. As described above, since the surface of the surface emitting laser element 10 is an XY plane, the window 30 and the surface emitting laser element 10 in a state of being overlaid on the XY plane are combined with the window 30 and the surface emitting laser element 10 on the XY plane. May be described. In this case, the window 30 and the surface emitting laser element 10 on the XY plane are the same as the window 30 and the surface emitting laser element 10 on the XY plane as viewed from the + Z-axis direction that is the emitting direction of the surface emitting laser.

  The window portion 30 is formed of a material that transmits light emitted from the surface-emitting laser element 10, and has a conical inclined portion 31 formed in a conical shape at the center portion. The window portion 30 is formed with a substantially uniform thickness as a whole, and the conical apex 32 is disposed so as to face the surface emitting laser element 10 side, that is, the −Z axis direction. Specifically, the conical inclined portion 31 in the window portion 30 is formed so that one surface is convex in a conical shape, and the other surface corresponds to the conical shape of the one surface. It is formed so as to be concave in a conical shape so that the thickness at is constant. As described above, the window 30 is installed so that one surface of the window 30, that is, the surface on which the conical apex 32 is formed faces the surface emitting laser element 10. Further, the conical inclined portion 31 is formed in a region wider than the region where the light emitting portion 11 is formed in the surface emitting laser element 10. That is, the size of the bottom surface of the cone of the cone inclined portion 31 is related to the size of the region where the light emitting portion 11 formed on the surface emitting laser element 10 is disposed. That is, in the present embodiment, in order to bring the position of the light beam closer to the axis 51 parallel to the Z axis, the size of the bottom surface of the cone is the light emitting unit 11 formed on the surface emitting laser element 10. It is the size which covers the area which is covered. FIG. 1 is a perspective view of a surface emitting laser module according to the present embodiment, and FIG. 2 is a cross-sectional view.

  As shown in FIG. 3, the light beam 41 emitted from the light emitting portion (VCSEL) 11 of the surface emitting laser element 10 is provided by installing the window portion 30 in which the conical inclined portion 31 is formed at a predetermined position of the package 20. Is bent at the interface of one surface of the window portion 30 when entering the window portion 30, and thereafter, is emitted to the window portion 30 at the interface of the other surface of the window portion 30 when exiting from the window portion 30. It is bent to the opposite side to the incident direction. Since the conical inclined portion 31 is formed so that one surface of the window portion 30 and the other surface are substantially parallel to each other, the light flux 42 and the light flux 41 are substantially parallel light fluxes. Is also emitted as a light beam passing through a conical apex 32 and approaching an axis 51 parallel to the Z axis. That is, the light beam 42 emitted from the window portion 30 is a light beam obtained by shifting the light beam 41 toward the conical apex 32 by the shift amount s.

This will be described more specifically. As shown in FIG. 3, the thickness of the window portion 30 is t, and the angle of the conical vertex 32 of the window portion 30 when cut by a plane parallel to the Z axis (for example, the YZ plane) including the conical vertex 32. Is θ. In this case, the incident angle φ1 when the light beam 41 emitted from the light emitting unit 11 is incident on the conical inclined portion 31 of the window portion 30 is expressed by the following equation (1). In addition, incident angle (phi) 1 is an angle | corner which makes with the normal line of the cone inclined part 31 of the window part 30 of the position where the light beam 41 injects.

φ1 = π / 2−θ (1)

When the refractive index of the window 30 is n2, and the refractive index of the medium in the space between the surface emitting laser element 10 and the window 30 is n1, the light beam 41 incident at an incident angle φ1 is one surface of the window 30. Is bent so as to have an emission angle φ2 at the interface of the window 30 and enters the inside of the window 30. This relationship is shown in (2) below.

n1 × sin φ1 = n2 × sin φ2 (2)

Further, the optical path L of the light incident into the window portion 30 is expressed by the following equation (3) because the thickness of the window portion 30 is t.

L = t / cosφ2 (3)

Thereafter, as shown in the equation (1) again, the light is emitted as a light beam 42 by being bent at the interface of the other surface of the window portion 30 so as to have an emission angle equal to the incident angle φ1. As described above, from the equations shown in (1) to (3), the shift amount s of the light beam 42 with respect to the light beam 41 on the XY plane is the equation shown in (4).

s = L × sin (φ1-φ2) (4)

Here, if the window portion 30 is formed of glass or the like, and nitrogen or the like is present in the space between the surface emitting laser element 10 and the window portion 30, θ = 75 ° and t = 250 μm. In this case, since n1 = 1.00 and n2 = 1.51, the shift amount s is 22.6 μm.

  As shown in FIG. 4, this is because the light beam 41 emitted from the light emitting unit 11 passes through the window 30, so that the shift amount s = sighs toward the conical apex 32 of the window 30 in the XY plane. It means that it is emitted as a light beam 42 shifted by 22.6 μm.

  As described above, the light beam 41 emitted from the light emitting portion 11 of the surface emitting laser element 10 is transmitted through the window portion 30 as shown in FIG. 5, so that the conical apex 32 of the window portion 30 in the XY plane is obtained. Is shifted by the shift amount s to the side where the signal exists. That is, the light beam 42 emitted from the window 32 is a light beam collected in the direction in which the conical apex 32 exists.

  Accordingly, the light emitting portions 11 formed in the surface emitting laser element 10 can be formed at positions separated from each other by the shift amount s. By forming the light emitting unit 11 at a position away from the light emitting unit 11 in this manner, heat generated in the light emitting unit 11 is not easily accumulated in the surface emitting laser element 10, thereby preventing the surface emitting laser element 10 from becoming high temperature. In addition, the lifetime of the surface emitting laser element 10 can be extended.

  Note that the light beams 42 emitted from the window 30 need to be formed at equal intervals in the sub-scanning direction when used in an image forming apparatus or the like. That is, as shown in FIG. 6, the plurality of light beams 42 on the XY plane are equally spaced d2 when all the light beams 42 are orthographically projected on a virtual line extending in the sub-scanning direction (Y-axis direction). In the sub-scanning direction, the pitch d1 is formed.

  In the surface emitting laser module according to the present embodiment, as shown in FIG. 5, in the XY plane, the interval between the light emitting portions 11 can be increased particularly at a position near the conical apex 32 of the window portion 30. This portion can be prevented from becoming hot due to heat generation. That is, the central portion of the plurality of light emitting portions 11 is particularly likely to be at a high temperature, but in the present embodiment, the light emitting portions 11 and 11 are arranged on the XY plane at the central portion where such light emitting portions 11 are gathered. By forming so that the conical apex 32 is located between them, the space | interval between the light emission parts 11 in this center part can be widened, and it can prevent becoming higher temperature. In this case, a conical apex 32 is present between the light emitting unit 11 and the light emitting unit 11. However, when the light emitting units 11 are arranged two-dimensionally, a conical shape is obtained. It is preferable that the vertex 32 is formed so as to be positioned at the center of the four light emitting portions 11 that are closest to each other in the central portion.

  As described above, the conical apex 32 of the window 30 is a position where the light emitting unit 11 and the conical apex 32 do not overlap with each other on the XY plane, and the center of gravity of the region where the plurality of light emitting units 11 are formed or It is preferably formed so as to be located in the vicinity of the center of gravity. In some cases, the center of gravity of the region where the plurality of light emitting units 11 are formed or the vicinity of the center of gravity is described as the center of gravity of the light emitting unit 11.

  In the above description, the window portion 30 is formed with a substantially uniform thickness as a whole. For example, in the window portion 30, the region where the cone of the cone inclined portion 31 is formed, and the cone The thickness of the region that is not formed may be different. That is, in the window portion 30, the region where the cones of the conical inclined portion 31 are formed with a substantially uniform thickness causes a shift of the light beam position by a predetermined amount.

  In addition, the window portion 30 is formed by forming the cone of the cone inclined portion 31 and the region not forming the cone separately or by using different materials. May be. For example, if the region where the cone is formed is formed of a material that transmits light, the region where the cone is not formed may be formed of a material that does not transmit light.

  Furthermore, the window part 30 should just be a material which permeate | transmits light, and if it says more, it should just be a material which permeate | transmits the light of the wavelength emitted from the light emission part 11 provided on the surface emitting laser element 10. FIG.

(Window part with pyramid inclined part)
Next, a surface emitting laser module having a window portion in which a pyramid inclined portion is formed will be described. As shown in FIGS. 7 and 8, this has a window portion 60 in which a pyramid-shaped pyramid inclined portion 61 is formed. The pyramid inclined portion 61 is preferably formed so that the ridge of the pyramid and the light emitting portion 11 do not overlap in the XY plane when the light emitting portions 11 are two-dimensionally arranged.

  Further, the window portion 60 has a pyramid apex 62 at substantially the center of the pyramid inclined portion 61. The position of the pyramid apex 62 is the same as the case of the position of the conical apex 32 described above. They are formed so as to be approximately the same position.

  Further, as shown in FIG. 8, the light beam 41 emitted from the light emitting unit 11 of the surface emitting laser element 10 becomes a light beam 43 by the pyramid inclined portion 61 and is emitted from the window portion 60. By forming such a pyramidal inclined portion 60 having a quadrangular pyramid shape, the light emitting portions 11 formed on the surface of the surface emitting laser element 10 can be arranged on straight lines extending in two directions.

[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.

  Based on FIG. 9, the laser printer 1000 in this Embodiment is demonstrated. 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 a 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”.

  In this case, the light beams 42 emitted from the light emitting portion 11 of the surface emitting laser element 10 and transmitted through the window portion 30 are formed at equal intervals as shown in FIG. That is, since the positional relationship of the light beam 42 when the perpendicular line is dropped in the direction corresponding to the sub-scanning direction in the light beam 42 transmitted through the window portion 30 is equal to d2, the photosensitive drum 1030 is adjusted by adjusting the lighting timing. Above, it can be understood that the configuration is the same as the case where the light sources are arranged at equal intervals in the sub-scanning direction. For example, if the pitch d1 of the light beam 42 transmitted through the window 30 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. Here, the outer periphery of the conical inclined portion 31 of the window portion 30 is 300 μm, and any light emitting portion (VCSEL) 11 actually corresponds to the shift amount s refracted by the window portion 30 as shown in FIG. It is formed at a position away from the conical apex 32 of the window 30 by a distance of 6 μm.

  Of course, if the number of light emitting portions (VCSEL) 11 in the direction corresponding to the main scanning direction is increased, an array arrangement in which the pitch d1 is narrowed and the interval d2 is further reduced, or the magnification of the optical system is lowered is more preferable. Higher density and higher quality printing are possible. Note that the writing interval in the main scanning direction can be easily controlled by the lighting timing of the light source.

  The optical system disposed 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 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.

  Based on FIG. 12, the color printer 2000 in this Embodiment is demonstrated. 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. 12, 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 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.

[Fourth Embodiment]
Next, a fourth embodiment will be described. The present embodiment is an optical transmission system. Based on FIG. 13, the optical transmission system 3000 according to the present embodiment will be described. In the optical transmission system 3000 according to the present embodiment, the optical transmission module 3001 and the optical reception module 3005 are connected by an optical fiber cable 3004, and one-way optical communication from the optical transmission module 3001 to the optical reception module 3005 is possible. It has become.

  The optical transmission module 3001 includes a light source 3002 including the surface emitting laser module according to the first embodiment, and a drive circuit that modulates the light intensity of the laser light output from the light source 3002 in accordance with an electric signal input from the outside. 3003.

  The optical signal output from the light source 3002 is coupled to the optical fiber cable 3004, guided through the optical fiber cable 3004, and input to the optical receiving module 3005.

  The optical receiving module 3005 includes a light receiving element 3006 that converts an optical signal into an electric signal, and a receiving circuit 3007 that performs signal amplification, waveform shaping, and the like on the electric signal output from the light receiving element 3006.

  According to the optical transmission module 3001 according to the present embodiment, since the light source 3002 includes the surface emitting laser module according to the first embodiment, a plurality of lights can be stably stabilized at a high density without increasing the cost. As a result, the optical signal can be stably generated without increasing the cost.

  Also, the optical transmission system 3000 according to the present embodiment includes the optical transmission module 3001 that can stably generate an optical signal without incurring an increase in cost, resulting in an increase in cost. Therefore, it is possible to stably perform large-capacity optical transmission with low power consumption.

  In the present embodiment, a configuration example of unidirectional communication with a single channel is shown. However, a configuration such as bidirectional communication, a parallel transmission method, and a wavelength division multiplexing transmission method can also be adopted. In short, the light source 3002 only needs to include the surface-emitting laser module in the first embodiment.

  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.

10 Surface emitting laser element 11 Light emitting part (VCSEL)
12 Substrate 20 Package 21 Bottom portion 30 Window portion 31 Conical inclined portion 32 Conical apex 41 Light flux (window portion 30 incident light)
42 Light flux (light emitted from window 30)
51 Axis 1000 passing through conical apex 32 Laser printer (image forming apparatus)
1010 Optical scanning device 2000 Color printer (image forming apparatus)
3000 Optical transmission system

JP 2001-85788 A JP 2002-359433 A JP 2008-192780 A

Claims (10)

A surface emitting laser element in which a plurality of surface emitting lasers are formed on a substrate surface;
A package for installing the surface-emitting laser element;
A window provided on the emission side of the surface emitting laser;
The window portion is formed of a material that transmits light having a wavelength of the surface emitting laser, and one surface of the window portion is formed to be convex in a cone shape, The other surface facing the surface is formed to be concave in a conical shape corresponding to the conical shape,
The region forming the conical shape in the window portion has a constant thickness,
A surface-emitting laser module, wherein the one surface of the window portion and the surface-emitting laser element are disposed to face each other.   2. The surface emitting laser module according to claim 1, wherein the conical shape is a conical shape or a quadrangular pyramid shape. The cone is a quadrangular pyramid,
2. The surface emitting laser module according to claim 1, wherein the quadrangular pyramid-shaped ridge is formed so as not to overlap the surface emitting laser when viewed from a direction perpendicular to the substrate surface.   The conical apex formed on one surface of the window is formed so as to be positioned between the surface emitting lasers when viewed from a direction perpendicular to the substrate surface. The surface emitting laser module according to claim 1. In the surface emitting laser element, the surface emitting lasers are two-dimensionally arranged,
The conical apex formed on one surface of the window portion is formed so as to be positioned approximately in the middle of the four surface emitting lasers closest to each other when viewed from the direction perpendicular to the substrate. The surface emitting laser module according to claim 1, wherein   A conical apex formed on one surface of the window is formed so as to be located at the center of gravity of the region where the surface emitting laser is formed when viewed from a direction perpendicular to the substrate. The surface emitting laser module according to claim 5.   The surface-emitting laser is arranged in the surface-emitting laser element so that the light beams emitted from the window portion are two-dimensionally equidistant on a plane substantially parallel to the substrate surface. The surface emitting laser module according to claim 5 or 6. An optical scanning device that scans a surface to be scanned with light,
A light source comprising the surface emitting laser module according to claim 1;
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 8, 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 9, wherein there are a plurality of the image carriers, and the image information is multicolor color information.

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