JP2019215441A - Optical module - Google Patents

Abstract

To provide an optical module that is excellent in stability of an operation of scanning light.SOLUTION: An optical module 1 includes: a laser diode; a mirror driving mechanism 120 having a base section 111 including a thick wall section 112, and a thin wall section 113 that contains a mirror 126 capable of swinging by resonance with a first shaft 125a as a swing shaft with respect to the base section 111 and reflecting light emitted from a laser diode, being supported by the base part 111, and being thinner than the thick wall section 112; and a mirror driving mechanism base 65 made of metal for supporting the mirror drive mechanism 120. The mirror drive mechanism 120 includes a metal die pad 136 disposed in an area facing the mirror drive mechanism base 65. By bonding the die pad 136 and the mirror drive mechanism base 65, the mirror drive mechanism 120 is supported by the mirror drive mechanism base 65.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical module.

  2. Description of the Related Art There is known an optical module including a light emitting unit that combines light from a plurality of semiconductor light emitting elements and a scanning unit that scans light from the light emitting unit (for example, see Patent Documents 1 to 3). Such an optical module can draw characters, figures, and the like by scanning light from the light emitting unit along a desired path.

JP 2014-186068 A JP 2014-56199 A International Publication No. 2007/120831

  In the optical module as described above, light is scanned by swinging a mirror that reflects light. Optical modules are required to have stable operation for scanning light.

  Therefore, it is an object to provide an optical module having excellent stability of an operation of scanning light.

  An optical module according to the present invention is capable of swinging by resonance with a laser diode, a base portion including a thick portion, and a first axis as a swing axis with respect to the base portion, and is emitted from the laser diode. A mirror driving mechanism that includes a mirror that reflects light, is supported by the base, and includes a thin portion thinner than the thick portion, and a metal mirror driving mechanism base that supports the mirror driving mechanism. The mirror driving mechanism includes a metal die pad arranged in a region facing the mirror driving mechanism base. The mirror drive mechanism is supported by the mirror drive mechanism base by joining the die pad and the mirror drive mechanism base.

  According to the above-described optical module, it is possible to provide an optical module having excellent stability in the operation of scanning light.

FIG. 3 is a diagram illustrating a mirror driving mechanism provided in the optical module according to the first embodiment. FIG. 2 is a cross-sectional view when the mirror driving mechanism illustrated in FIG. 1 is cut along a line II-II. FIG. 3 is a schematic perspective view illustrating a structure of an optical module including a mirror driving mechanism. FIG. 3 is a schematic perspective view illustrating a structure of an optical module including a mirror driving mechanism. FIG. 4 is a perspective view corresponding to a state where a cap of FIG. 3 is removed. FIG. 5 is a perspective view corresponding to a state where a cap of FIG. 4 is removed. It is the schematic in the XY plane which showed the cap in the cross section and other components in planar view. It is the schematic in the XZ plane which showed the cap in the cross section and other components in planar view.

[Description of Embodiment of Present Invention]
First, embodiments of the present invention will be listed and described. The optical module of the present application is a laser diode, a base part including a thick part, and is capable of swinging by resonance with the first axis as a swing axis with respect to the base part, and reflects light emitted from the laser diode. A mirror driving mechanism including a thin mirror portion supported by the base portion and having a thinner portion than the thick portion, and a metal mirror driving mechanism base supporting the mirror driving mechanism. The mirror driving mechanism includes a metal die pad arranged in a region facing the mirror driving mechanism base. The mirror drive mechanism is supported by the mirror drive mechanism base by joining the die pad and the mirror drive mechanism base.

  Generally, the optical deflection angle of a mirror that fluctuates due to resonance changes with temperature. In the optical module of the present application, the mirror driving mechanism includes a metal die pad arranged in a region facing the mirror driving mechanism base. The mirror driving mechanism is supported by the mirror driving mechanism base by joining the metal die pad and the mirror driving mechanism base. Therefore, the heat of the mirror driving mechanism can be easily transmitted to the mirror driving mechanism base through the metal die pad. In such an optical module, it is easy to adjust the temperature of the mirror to a desired range. Therefore, according to the optical module of the present application, it is possible to provide an optical module having excellent stability of the operation of scanning light.

  In the above optical module, the material of the die pad may include at least one of copper, aluminum, and gold. Copper, aluminum and gold all have relatively high thermal conductivities. Therefore, by using such a metal as the material of the die pad, the heat of the mirror driving mechanism can be efficiently transmitted to the mirror driving mechanism base side, and the operation of scanning light can be further stabilized.

  In the above-mentioned optical module, the mirror driving mechanism and the mirror driving mechanism base may be joined by an adhesive containing metal. By doing so, it is possible to improve the heat conduction also at the portion where the mirror driving mechanism and the mirror driving mechanism base are joined. Therefore, the heat of the mirror driving mechanism can be efficiently transmitted to the mirror driving mechanism base side, and the light scanning operation can be further stabilized.

  The optical module may further include an electronic temperature adjustment module that is arranged in contact with the mirror driving mechanism base and adjusts the temperature of the mirror driving mechanism. By doing so, it becomes easy to adjust the temperature of the mirror driving mechanism supported by the mirror driving mechanism base to a desired range via the mirror driving mechanism base. Therefore, it becomes easy to stabilize the operation of scanning light.

  The optical module may further include a beam shaping unit for shaping a shape in a cross section perpendicular to a traveling direction of light emitted from the laser diode. By doing so, light shaped into a desired shape can be reflected by the mirror.

  The optical module may further include a light receiving element that receives light emitted from the laser diode. This makes it possible to appropriately adjust the output of the laser diode based on the output of the light received by the light receiving element.

  The optical module may further include a lens that converts a spot size of light emitted from the laser diode. By doing so, light having a desired spot size can be emitted from the optical module.

  In the above optical module, a protection member for sealing the laser diode, the mirror driving mechanism, and the mirror driving mechanism base may be further provided. By doing so, the laser diode, the mirror driving mechanism, and the mirror driving mechanism base constituting the optical module can be effectively protected from the external environment, and high reliability can be secured. Therefore, the operation of scanning light can be further stabilized.

  The optical module may further include a filter that includes a plurality of laser diodes and combines light emitted from the plurality of laser diodes. By doing so, it is possible to emit from the optical module light obtained by multiplexing the light emitted from the plurality of laser diodes.

  In the optical module, the plurality of laser diodes may include a laser diode that emits red light, a laser diode that emits green light, and a laser diode that emits blue light. By doing so, these lights can be combined to form light of a desired color.

[Details of the embodiment of the present invention]
Next, an embodiment of an optical module according to the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts have the same reference characters allotted, and description thereof will not be repeated.

(Embodiment 1)
First, the configuration of the mirror driving mechanism provided in the optical module according to the first embodiment will be described with reference to FIGS. FIG. 1 is a diagram illustrating a mirror driving mechanism provided in the optical module according to the first embodiment. FIG. 2 is a sectional view when the mirror driving mechanism shown in FIG. 1 is cut along a line II-II.

  With reference to FIGS. 1 and 2, mirror drive mechanism 120 in the present embodiment includes base portion 111 including thick portion 112 and thin portion 113 thinner than thick portion 112. The mirror driving mechanism 120 has a plate shape. As shown in FIG. 1, the outer edge 114 of the base portion 111 has a rectangular shape when viewed in a plan view from the plate thickness direction. For example, 4.5 mm is selected as the length of the base portion 111 in the short direction, which is the direction indicated by the arrow D in FIG. As the length in the longitudinal direction of the base portion 111 which is a direction orthogonal to the direction indicated by the arrow D in FIG. 1, for example, 8 mm is selected. The thick part 112 is formed in an annular shape. The corner of the outer edge 114 of the base 111 may be chamfered. The thick part 112 is arranged so as to include the outer edge 114 of the base part 111. In the base portion 111, a through hole 115 penetrating in the thickness direction is formed. Base portion 111 includes a pair of protrusions 117a and 117b extending from a region where inner edge 116 of thick portion 112 is located. The thickness of the pair of protruding portions 117a and 117b is smaller than the thickness of the thick portion 112. One surface 118a, 118b of the protruding portions 117a, 117b in the plate thickness direction is formed so as to be continuous with one surface 119 of the thick portion 112 in the plate thickness direction (see especially FIG. 2). In FIG. 1, the boundary between the thick portion 112 and each of the pair of protrusions 117a and 117b is indicated by a broken line.

  The thin portion 113 is supported by the base portion 111. Specifically, it is supported by a pair of thin rod-shaped second hinges 121a and 121b extending from the pair of protrusions 117a and 117b. Part of the outer edge 124 of the thin portion 113 is connected to and supported by the pair of projecting portions 117a and 117b by the pair of second hinges 121a and 121b. The thickness of the thin portion 113 is about 10 μm. The heat generated in the thin portion 113 is transmitted to the thick portion 112 through the pair of second hinges 121a and 121b and the pair of protrusions 117a and 117b, and is radiated.

  A pair of piezo elements 122a and 122b are arranged on the surface 118a of the protrusion 117a. The piezo elements 122a and 122b are arranged at intervals in the direction of arrow D. Each of the piezo elements 122a and 122b has a rectangular shape when viewed two-dimensionally from the plate thickness direction. Similarly, a pair of piezo elements 123a and 123b each having a rectangular shape when viewed in a plan view from the plate thickness direction are arranged on the surface 118b of the protrusion 117b at intervals in the direction of arrow D. By alternately applying opposite-phase voltages to the piezo elements 122a and 122b, and alternately applying opposite-phase voltages to the piezo elements 123a and 123b, the first and second piezo elements 123a and 123b pass through a pair of second hinges 121a and 121b indicated by a chain line. The thin portion 113 can be rocked using the second shaft 125b as a rocking axis. That is, the thin portion 113 can be swung by the piezoelectric phenomenon using the second axis as the swing axis. The base portion 111 corresponds to a supporting portion that supports the thin portion 113 so as to swing. Here, the swing of the thin portion 113 is, for example, a non-resonant type. The optical deflection angle of the swing of the thin portion 113 in the vertical direction is, for example, ± 15 °.

  The thin portion 113 includes a mirror 126. The mirror 126 reflects light incident from outside the mirror driving mechanism 120. The mirror 126 has a disk shape. As the diameter of the mirror 126, for example, 1.2 mm is selected. On the mirror surface of the mirror 126, for example, metal such as aluminum is deposited. The mirror 126 is connected to a support portion 134 included in the thin portion 113 by a pair of thin rod-shaped first hinges 127a and 127b. The mirror 126 is supported by the support 134 by a pair of first hinges 127a and 127b. Except for the region where the pair of first hinges 127a and 127 are arranged, a through hole 128 is formed on the outer diameter side of the outer edge of the mirror 126. A piezo element 131a is formed along one semicircular outer edge 129a of the through hole 128 partitioned by the pair of first hinges 127a, 127b. A piezo element 131b is formed along the other semicircular outer edge 129b of the through hole 128 partitioned by the pair of first hinges 127a and 127b. Each of the piezo elements 131a and 131b is arranged on one surface 133 of the thin portion 113. By alternately applying opposite-phase voltages to the piezo elements 131a and 131b, respectively, the mirror 126 is driven by using a first axis 125a passing through a pair of first hinges 127a and 127b and orthogonal to a second axis as a swing axis. Can be swung. The first axis 125a is indicated by a dashed line. That is, the mirror 126 can be swung with respect to the base 111 by the piezoelectric phenomenon with the first axis as the swing axis. Here, the swing of the mirror 126 is made in a resonance type. That is, the mirror 126 is vibrated in accordance with the natural frequency. By employing the resonance mode, it is easy to swing the mirror 126 at high speed. Further, by doing so, the optical deflection angle of the swing of the mirror 126 in the horizontal direction can be increased. The optical deflection angle is, for example, ± 40 °.

  Next, a method of manufacturing the mirror driving mechanism 120 will be briefly described. First, an SOI (Silicon on Insulator) substrate is prepared, and a silicon oxide film layer or the like containing silicon is formed thereon. Thereafter, a piezo element or the like is formed at a predetermined location by forming a photoresist layer, reactive ion etching, or the like, to obtain the mirror driving mechanism 120 described above.

  The mirror driving mechanism 120 includes a die pad 136 (see especially FIG. 2). The die pad 136 is made of metal. Preferably, the material of the die pad 136 is made of a metal including at least one of copper, aluminum and gold. The die pad 136 is arranged on a surface 137 of the thick portion 112 that is located on the opposite side of the surface 119 in the thickness direction. In the present embodiment, the die pad 136 is disposed so as to cover the entire surface 137 in the region where the thick portion 112 is formed. That is, the die pad 136 includes a rectangular outer edge 141 and a rectangular inner edge 142 when viewed in a plan view from the plate thickness direction. The die pad 136 is formed, for example, by depositing the above-described metal on the surface 137. In the mirror driving mechanism 120, the die pad 136 is arranged in a region facing a mirror driving mechanism base 65 described later.

  Next, a configuration of an optical module including the mirror driving mechanism 120 according to the first embodiment will be described with reference to FIGS. FIG. 3 is a schematic perspective view showing the structure of the optical module including the mirror driving mechanism 120. FIG. 4 is a schematic perspective view showing the structure of the optical module viewed from a different viewpoint from FIG. FIG. 5 is a perspective view corresponding to a state where the cap 40 of FIG. 3 is removed. FIG. 6 is a perspective view corresponding to a state where the cap 40 of FIG. 4 is removed. FIG. 7 is a schematic diagram in the XY plane showing the cross section of the cap 40 and other components in plan view. FIG. 8 is a schematic diagram in the XZ plane showing the cap 40 in cross section and other components in plan view. 5 to 8, the illustration of the mirror driving mechanism 120 is simplified.

  3 to 8, the optical module 1 according to the present embodiment includes a light forming unit 20 that forms light, and a protection member 2 that surrounds the light forming unit 20 and seals the light forming unit 20. And The protection member 2 includes a base 10 as a base body, and a cap 40 serving as a lid welded to the base 10. That is, the light forming part 20 is hermetically sealed by the protection member 2. The base 10 has a flat plate shape. The light forming unit 20 is arranged on one main surface 10 </ b> A of the base 10. The cap 40 is disposed in contact with one main surface 10 </ b> A of the base 10 so as to cover the light forming unit 20. A plurality of lead pins 51 are installed on the base 10 so as to penetrate from the other main surface 10B side to the one main surface 10A side of the base 10 and protrude on both sides of the one main surface 10A side and the other main surface 10B side. Have been. In a space surrounded by the base 10 and the cap 40, a gas from which moisture such as dry air has been reduced (removed) is sealed. A window 42 is formed in the cap 40. The window 42 is fitted with, for example, a parallel plate-shaped glass member. In the present embodiment, the protection member 2 is an airtight member that makes the inside airtight. Thereby, each member included in the light forming unit 20 is effectively protected from the external environment, and high reliability can be secured.

  The light forming section 20 includes a base member 4, laser diodes 81, 82, 83, lenses 91, 92, 93, a photodiode 94 as a light receiving element, filters 97, 98, 99, and a beam shaping section. An aperture member 55 and a mirror driving mechanism 120 are included. That is, the mirror driving mechanism 120 included in the light forming unit 20 is hermetically sealed by the protection member 2 together with the laser diode 81 and the like.

  The base member 4 includes an electronic temperature adjustment module 30, a laser diode base 60, and a mirror driving mechanism base 65. The electronic temperature adjustment module 30 includes a heat absorbing plate 31, a heat radiating plate 32, and a semiconductor pillar 33 as shown in FIG. The electronic temperature adjustment module 30 is arranged on one main surface 10A of the base 10 so that the heat sink 32 contacts one main surface 10A of the base 10. The mirror driving mechanism base 65 and the mirror driving mechanism 120 are disposed on the opposite side to a third filter 99 described later when viewed from the aperture member 55.

  The electronic temperature adjustment module 30 is arranged between the base 10 and the laser diode base 60 and the mirror driving mechanism base 65. Laser diode base 60 is arranged on heat absorbing plate 31 such that the other main surface 60 </ b> B of laser diode base 60 contacts heat absorbing plate 31. The heat sink 32 is arranged in contact with one main surface 10 </ b> A of the base 10. The electronic temperature adjustment module 30 is a Peltier module (Peltier element) that is an electronic cooling module. In the present embodiment, when a current flows through the electronic temperature adjustment module 30, the heat of the laser diode base 60 contacting the heat absorbing plate 31 moves to the base 10, and the laser diode base 60 is cooled. Here, the electronic temperature adjustment module 30 performs temperature control based on temperature information detected by, for example, a thermistor 100 disposed on a chip mounting area 62 described later. As a result, the temperatures of the laser diodes 81, 82, 83 are adjusted to an appropriate temperature range.

  The mirror driving mechanism base 65 is arranged on the heat absorbing plate 31 so as to be in contact with the heat absorbing plate 31. The mirror driving mechanism base 65 has a triangular prism shape (straight triangular prism). The mirror driving mechanism base 65 is made of metal. The mirror driving mechanism base 65 is arranged on the heat absorbing plate 31 so that the one side surface of the triangular prism contacts the heat absorbing plate 31. 2, the mirror driving mechanism 120 including the mirror 126 is disposed on the other side surface 138 of the mirror driving mechanism base 65. The mirror driving mechanism 120 and the mirror driving mechanism base 65 are joined by an adhesive 140 containing metal. Specifically, the surface 139 of the die pad 136 disposed in the region facing the mirror driving mechanism base 65 and the side surface 138 of the mirror driving mechanism base 65 are joined by an adhesive 140 containing metal. As the adhesive 140 containing a metal, for example, a silver paste is used. Thus, the mirror driving mechanism 120 is supported by the mirror driving mechanism base 65. The temperature of the mirror drive mechanism 120 is adjusted by the electronic temperature adjustment module 30 via the mirror drive mechanism base 65.

  The laser diode base 60 has a plate shape. The laser diode base 60 has one main surface 60A having a rectangular shape (square shape) when viewed in plan. One main surface 60 </ b> A of laser diode base 60 includes a lens mounting area 61, a chip mounting area 62, and a filter mounting area 63. The chip mounting region 62 is formed in a region including one side of one main surface 60A along the one side. The lens mounting area 61 is arranged adjacent to the chip mounting area 62 and along the chip mounting area 62. The filter mounting area 63 is arranged along the other side of the one main surface 60A in an area including the other side facing the one side. The chip mounting area 62, the lens mounting area 61, and the filter mounting area 63 are parallel to each other.

  The thickness of the laser diode base 60 in the lens mounting area 61 is equal to the thickness of the laser diode base 60 in the filter mounting area 63. The lens mounting area 61 and the filter mounting area 63 are included on the same plane. The thickness of the laser diode base 60 in the chip mounting area 62 is larger than the lens mounting area 61 and the filter mounting area 63. As a result, the height of the chip mounting region 62 (the height based on the lens mounting region 61, that is, the height in the direction perpendicular to the lens mounting region 61) is higher than the lens mounting region 61 and the filter mounting region 63. Has become.

  On the chip mounting area 62, a first submount 71, a second submount 72, and a third submount 73 in a plate shape are arranged side by side along the above one side of one main surface 60A. The second submount 72 is arranged so as to be sandwiched between the first submount 71 and the third submount 73. On the first submount 71, a red laser diode 81 as a first laser diode is arranged. On the second submount 72, a green laser diode 82 as a second laser diode is arranged. On the third submount 73, a blue laser diode 83 as a third laser diode is arranged. The height of the optical axis of the red laser diode 81, the green laser diode 82, and the blue laser diode 83 (distance between the reference plane and the optical axis when the lens mounting area 61 of the one main surface 60A is used as the reference plane; Z-axis direction) Are adjusted by the first sub-mount 71, the second sub-mount 72, and the third sub-mount 73 so as to coincide with each other. A thermistor 100 for detecting the temperature of the laser diode base 60 is arranged on the chip mounting area 62 at a distance from the first submount 71 in the X direction.

  On the lens mounting area 61, a first lens 91, a second lens 92, and a third lens 93 are arranged. The first lens 91, the second lens 92, and the third lens 93 have lens portions 91A, 92A, 93A each having a lens surface. In the first lens 91, the second lens 92, and the third lens 93, the lens portions 91A, 92A, 93A and regions other than the lens portions 91A, 92A, 93A are integrally molded. The central axes of the lens portions 91A, 92A, 93A of the first lens 91, the second lens 92, and the third lens 93, that is, the optical axes of the lens portions 91A, 92A, 93A are red laser diode 81, green laser diode 82, and red laser diode 82, respectively. It coincides with the optical axis of the blue laser diode 83. The first lens 91, the second lens 92, and the third lens 93 convert the spot size of light emitted from the red laser diode 81, the green laser diode 82, and the blue laser diode 83, respectively (to change the beam shape on a certain projection surface). Shape into the desired shape). The spot size is converted by the first lens 91, the second lens 92, and the third lens 93 so that the spot sizes of the light emitted from the red laser diode 81, the green laser diode 82, and the blue laser diode 83 match. The light emitted from the red laser diode 81, the green laser diode 82, and the blue laser diode 83 is converted into collimated light by the first lens 91, the second lens 92, and the third lens 93.

  On the filter mounting area 63, a first filter 97, a second filter 98, and a third filter 99 are arranged. The first filter 97 is arranged on a straight line connecting the red laser diode 81 and the first lens 91. A second filter 98 is arranged on a straight line connecting the green laser diode 82 and the second lens 92. A third filter 99 is arranged on a straight line connecting the blue laser diode 83 and the third lens 93. Each of the first filter 97, the second filter 98, and the third filter 99 has a flat plate shape having main surfaces parallel to each other. The first filter 97, the second filter 98, and the third filter 99 are, for example, wavelength-selective filters. The first filter 97, the second filter 98, and the third filter 99 are, for example, dielectric multilayer filters.

  More specifically, the first filter 97 reflects red light. The second filter 98 transmits red light and reflects green light. The third filter 99 transmits red light and green light, and reflects blue light. Thus, the first filter 97, the second filter 98, and the third filter 99 selectively transmit and reflect light of a specific wavelength. As a result, the first filter 97, the second filter 98, and the third filter 99 combine the lights emitted from the red laser diode 81, the green laser diode 82, and the blue laser diode 83.

  The aperture member 55 is disposed on the heat absorbing plate 31. The aperture member 55 is arranged on the side opposite to the second filter 98 when viewed from the third filter 99. The aperture member 55 has a flat plate shape. The aperture member 55 has a through hole 55A that penetrates the aperture member 55 in the thickness direction. In the present embodiment, the cross section perpendicular to the extending direction of through-hole 55A has a circular shape. The aperture member 55 is arranged such that the through hole 55A is located in a region corresponding to the optical path of the light combined in the first filter 97, the second filter 98, and the third filter 99. The through-hole 55A extends along the optical path of the light multiplexed in the first filter 97, the second filter 98, and the third filter 99. The shape of the light emitted from the laser diodes 81, 82, and 83 in a cross section perpendicular to the light traveling direction is elliptical. In a section perpendicular to the light traveling direction, the diameter of the through-hole 55A is smaller than the major axis of the light combined by the filters 97, 98, and 99, and the light of the light combined with the central axis of the through-hole 55A. The aperture member 55 is arranged so that the axes coincide. As a result, the shape of the cross section perpendicular to the traveling direction of the lights multiplexed by the filters 97, 98, and 99 is shaped into a shape smaller than the inner diameter of the through hole 55A of the aperture member 55.

  Referring to FIG. 7, red laser diode 81, lens portion 91A of first lens 91, and first filter 97 are arranged in a straight line along the light emission direction of red laser diode 81 (in the Y-axis direction). ) Is located. The green laser diode 82, the lens portion 92A of the second lens 92, and the second filter 98 are arranged in a straight line (along the Y-axis direction) along the light emission direction of the green laser diode 82. The blue laser diode 83, the lens portion 93A of the third lens 93, and the third filter 99 are arranged along a straight line (along the Y-axis direction) along the light emission direction of the blue laser diode 83.

  The emission direction of the red laser diode 81, the emission direction of the green laser diode 82, and the emission direction of the blue laser diode 83 are parallel to each other. The main surfaces of the first filter 97, the second filter 98, and the third filter 99 are inclined at 45 degrees with respect to the emission direction (Y-axis direction) of the red laser diode 81, the green laser diode 82, and the blue laser diode 83, respectively. I have.

  The photodiode 94 is arranged on one main surface 60 </ b> A of the laser diode base 60. The photodiode 94 includes a light receiving unit 94A. The blue laser diode 83, the lens portion 93A of the third lens 93, the third filter 99, and the light receiving portion 94A of the photodiode 94 are arranged in a straight line along the light emitting direction of the blue laser diode 83 (in the Y-axis direction). At). In the present embodiment, the third filter 99 transmits most of the red and green light, but reflects part of it. The third filter 99 reflects most of the blue light but transmits part of the blue light.

Next, the operation of the optical module 1 according to the present embodiment will be described. Referring to FIG. 7, the red light emitted from the red laser diode 81 travels along the optical path L _1. The red light enters the lens portion 91A of the first lens 91, and the spot size of the light is converted. Specifically, for example, red light emitted from the red laser diode 81 is converted into collimated light. Red light spot size is converted in the first lens 91 along the optical path L ₁ proceeds, is incident on the first filter 97.

The first filter 97 is for reflecting the red light, the light emitted from the red laser diode 81 further proceeds along the optical path L _4, is incident on the second filter 98. The second filter 98 is for transmitting the red light, the light emitted from the red laser diode 81 further proceeds along the optical path L _4, is incident on the third filter 99. The third filter 99 is for transmitting the red light, the light emitted from the red laser diode 81 further proceeds along the optical path L _4, and reaches the aperture member 55. The light that has reached the aperture member 55 is shaped by the aperture member 55, further travels along the optical path L ₄ , and reaches the mirror 126.

Green light emitted from the green laser diode 82 travels along the optical path L _2. This green light enters the lens portion 92A of the second lens 92, and the spot size of the light is converted. Specifically, for example, green light emitted from the green laser diode 82 is converted into collimated light. Green light spot size is converted in the second lens 92 along the optical path L ₂ progresses, is incident on the second filter 98.

The second filter 98 for reflecting green light, the light emitted from the green laser diode 82 further proceeds along the optical path L _4, is incident on the third filter 99. The third filter 99 is for transmitting the green light, the light emitted from the green laser diode 82 further proceeds along the optical path L _4, and reaches the aperture member 55. The green light that has reached the aperture member 55 is shaped by the aperture member 55, further travels along the optical path L ₄ , and reaches the mirror 126.

Blue light emitted from the blue laser diode 83 travels along the optical path L _3. This blue light is incident on the lens portion 93A of the third lens 93, and the spot size of the light is converted. Specifically, for example, blue light emitted from the blue laser diode 83 is converted into collimated light. Blue light spot size is converted in the third lens 93 along the optical path L ₃ progresses, incident on the third filter 99.

The third filter 99 is for reflecting the blue light, the light emitted from the blue laser diode 83 further proceeds along the optical path L _4, and reaches the aperture member 55. Blue light that reaches the aperture member 55 is shaped by the aperture member 55, further proceeds along the optical path L _4, and reaches the mirror 126.

In this way, the red, green and light blue light is formed by combining (multiplexing light) reaching the mirror 126 along the optical path L _4. Then, referring to FIG. 8, the multiplexed light by the mirror 126 is driven is scanned by multiplexing light through the window 42 along the optical path L ₁₀ emitted to the outside of the cap 40 characters, figures and the like Is drawn.

  As described above, the optical module 1 includes the mirror driving mechanism 120 that scans the combined light. The mirror driving mechanism 120 includes a metal die pad 136 disposed in a region facing the mirror driving mechanism base 65. The mirror drive mechanism 120 is supported by the mirror drive mechanism base 65 by joining the die pad 136 and the mirror drive mechanism base 65. Therefore, the heat of the mirror driving mechanism 120 can be easily transmitted to the mirror driving mechanism base 65 through the metal die pad 136. In such an optical module 1, it is easy to adjust the temperature of the mirror 126 to a desired range. Therefore, according to the optical module 1 of the present application, it is possible to provide the optical module 1 having excellent stability of the operation of scanning light.

  In particular, for example, when the optical module 1 is mounted on an automobile, the optical module 1 may be used in a wide temperature range of −45 ° C. to 95 ° C. Even in such a case, in the present embodiment, the temperature of the mirror driving mechanism 120 can be easily appropriately adjusted by the electronic temperature adjustment module 30 via the mirror driving mechanism base 65, and the light scanning operation can be performed. Can be stabilized.

  In the present embodiment, the material of die pad 136 includes at least one of copper, aluminum, and gold. Copper, aluminum and gold all have relatively high thermal conductivities. Therefore, by using such a metal as the material of the die pad 136, the heat of the mirror driving mechanism 120 can be efficiently transmitted to the mirror driving mechanism base 65 side, and the light scanning operation can be further stabilized. .

  In the present embodiment, since the mirror driving mechanism 120 and the mirror driving mechanism base 65 are joined by the adhesive 140 containing metal, the mirror driving mechanism 120 and the mirror driving mechanism base 65 are also joined at the portion where the mirror driving mechanism 120 and the mirror driving mechanism base 65 are joined. , Heat conduction can be improved. Therefore, the heat of the mirror driving mechanism 120 can be efficiently transmitted to the mirror driving mechanism base 65 side, and the operation of scanning light can be further stabilized.

  In the present embodiment, the optical module 1 includes an electronic temperature adjustment module 30 that is arranged in contact with the mirror driving mechanism base 65 and adjusts the temperature of the mirror driving mechanism 120. Therefore, it becomes easy to adjust the temperature of the mirror driving mechanism 120 supported by the mirror driving mechanism base 65 to a desired range via the mirror driving mechanism base 65. Therefore, it becomes easy to stabilize the operation of scanning light.

A part of the light of the red and green reaching the third filter 99, is reflected by the third filter 99, incident on the light receiving portion 94A of the photodiode 94 and traveling along the optical path L ₅ and L ₆ . Part of the blue light that has reached the third filter 99, passes through the third filter 99, and proceeds along the optical path L ₆ incident on the light receiving portion 94A of the photodiode 94. Then, the current values flowing through the red laser diode 81, the green laser diode 82, and the blue laser diode 83 are adjusted based on the information on the intensity of the red, green, and blue light received by the photodiode 94. That is, in the present embodiment, the red laser diode 81, the green laser diode 82, and the blue laser diode 83 can be controlled by APC (Auto Power Control) driving. In this way, strict control of the laser diodes 81, 82, 83 can be performed. That is, the outputs of the laser diodes 81, 82, and 83 can be appropriately adjusted based on the output of the light received by the photodiode 94.

  The optical module 1 includes the aperture member 55 as a beam shaping unit that shapes the cross section perpendicular to the traveling direction of the light emitted from the laser diodes 81, 82, and 83. The light can be reflected by the mirror 126.

  Since the optical module 1 includes the lenses 91, 92, and 93 that convert the spot size of the light emitted from the laser diodes 81, 82, and 83, light having a desired spot size can be emitted from the optical module 1. it can.

  The optical module 1 includes the protection members 2 for sealing the laser diodes 81, 82, 83, the mirror driving mechanism 120, and the mirror driving mechanism base 65. Therefore, the laser diodes 81, 82, 83, the mirror drive mechanism 120, and the mirror drive mechanism base 65 that constitute the optical module 1 can be effectively protected from the external environment, and high reliability can be secured. Therefore, the operation of scanning light can be further stabilized.

  The optical module 1 includes a plurality of laser diodes 81, 82, and 83, and filters 98 and 99 for multiplexing light emitted from the plurality of laser diodes 81, 82, and 83. The light obtained by multiplexing the light emitted from 82 and 83 can be emitted from the optical module 1.

  In the optical module 1, the plurality of laser diodes 81, 82, and 83 are a red laser diode 81 that emits red light, a green laser diode 82 that emits green light, and a blue laser diode that emits blue light. 83, these lights can be combined to form light of a desired color.

  In the optical module 1, an aperture member 55 is employed as a beam shaping unit. As the beam shaping unit, a lens, a prism, or the like can be employed. However, by employing the aperture member 55 as the beam shaping unit, the manufacturing cost of the optical module 1 can be reduced.

  In the optical module 1, the outer diameter of the mirror 126 may be equal to or larger than the beam diameter of the light shaped by the aperture member 55 (the diameter of the light in a cross section perpendicular to the light traveling direction). Accordingly, it is possible to prevent light that has reached the mirror driving mechanism 120 but is not scanned by the mirror 126 from being reflected at a location other than the mirror 126 and causing stray light.

(Other embodiments)
In the above embodiment, the light forming section 20 of the optical module 1 includes the photodiode 94 as a light receiving element. However, the present invention is not limited to this. ACC (Auto Current Control) drive which determines the value of the current flowing through the laser diode based on the intensity of the light of the above. By doing so, the photodiode 94 can be omitted, and the manufacturing cost of the optical module 1 can be reduced. When the relationship between the current flowing through the laser diode and the intensity of light emitted from the laser diode changes due to a change in temperature, there is a disadvantage that it becomes difficult to appropriately control the intensity of light. This disadvantage can be compensated for in the optical module 1 of the present application by adjusting the temperature of the laser diode by the second electronic temperature adjustment module 34.

  In the above embodiment, the case where light from three laser diodes is multiplexed has been described. However, the number of laser diodes may be two or four or more. Further, in the above-described embodiment, the case where wavelength selective filters are employed as the first filter 97, the second filter 98, and the third filter 99 has been exemplified. However, these filters are, for example, polarization combining filters. You may.

  Further, in the above-described embodiment, a case where a plurality of laser diodes are provided has been described. In this case, no filter is required, and the light is combined with the light of a laser diode that emits light of another color outside the optical module 1 as necessary.

  In the above embodiment, the die pad 136 is arranged so as to cover the surface 137 of the thick portion 112. However, the present invention is not limited to this, and the die pad 136 is covered on a part of the surface 137. There may be no areas. Further, when viewed in a plan view from the plate thickness direction, the die pad 136 may be disposed inside the inner edge 116 of the base portion 111. Although silver paste is used as an adhesive for joining the die pad 136 and the mirror drive mechanism base 65, an adhesive containing another metal may be used.

  It should be understood that the embodiments disclosed this time are illustrative in all aspects and are not restrictive in any aspect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The optical module of the present application can be particularly advantageously applied to an optical module that is excellent in stability of an operation of scanning light.

DESCRIPTION OF SYMBOLS 1 Optical module 2 Protective member 4 Base member 10 Base 10A, 10B Main surface 20 Light forming part 30 Electronic temperature control module 31 Heat absorption plate 32 Heat sink 33 Semiconductor pillar 40 Cap 42 Window 51 Lead pin 55 Aperture member 55A Through hole 60 Laser diode base 60A, 60B Main surface 61 Lens mounting area 62 Chip mounting area 63 Filter mounting area 65 Mirror drive mechanism base 71 First submount 72 Second submount 73 Third submount 81 Red laser diode 82 Green laser diode 83 Blue laser diode 91 First lens 91A, 92A, 93A Lens part 92 Second lens 93 Third lens 94 Photodiode 94A Light receiving part 97 First filter 98 Second filter 99 Third filter 100 Thermistor 111 Base part 112 Thickness Part 113 Thin part 114, 124, 129a, 129b, 141 Outer edge 115, 128 Through hole 116, 142 Inner edge 117a, 117b Projection 118a, 118b, 119, 133, 137, 138, 139 Surface 120 Mirror drive mechanism 121a, 121b Second hinges 122a, 122b, 123a, 123b, 131a, 131b Piezo elements 125a, 125b Axis 126 Mirrors 127a, 127b First hinge 134 Support section 136 Die pad 140 Adhesive

Claims (10)

A laser diode,
A base portion including a thick portion, and a mirror that is swingable by resonance with the first axis as a swing axis with respect to the base portion and reflects light emitted from the laser diode; And a mirror driving mechanism including a thin portion thinner than the thick portion,
A metal mirror drive mechanism base supporting the mirror drive mechanism,
The mirror driving mechanism includes a metal die pad arranged in a region facing the mirror driving mechanism base,
The optical module, wherein the mirror driving mechanism is supported by the mirror driving mechanism base by joining the die pad and the mirror driving mechanism base. The optical module according to claim 1, wherein the material of the die pad includes at least one of copper, aluminum, and gold. The optical module according to claim 1, wherein the mirror driving mechanism and the mirror driving mechanism base are joined by an adhesive containing a metal. 4. The optical module according to claim 1, further comprising an electronic temperature adjustment module arranged in contact with the mirror drive mechanism base and configured to adjust a temperature of the mirror drive mechanism. 5. The optical module according to claim 1, further comprising a beam shaping unit configured to shape a shape in a cross section perpendicular to a traveling direction of light emitted from the laser diode. The optical module according to any one of claims 1 to 5, further comprising a light receiving element that receives light emitted from the laser diode. The optical module according to claim 1, further comprising a lens that converts a spot size of light emitted from the laser diode. 8. The optical module according to claim 1, further comprising a protection member that seals the laser diode, the mirror driving mechanism, and the mirror driving mechanism base. 9. Comprising a plurality of the laser diodes,
The optical module according to any one of claims 1 to 8, further comprising a filter that multiplexes light emitted from the plurality of laser diodes. The plurality of laser diodes,
A red laser diode that emits red light,
A green laser diode that emits green light,
The optical module according to claim 9, comprising: a blue laser diode that emits blue light.

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