JP7043049B2 - Laser projection device - Google Patents

Description

The present invention relates to a laser projection device.

A technique is known in which a laser beam oscillated by a laser element is monitored by a light receiving element to feedback control the laser element (for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2011-134736 Japanese Unexamined Patent Publication No. 2011-8221

Depending on the application of the laser module, it is desired that the light intensity of the laser light emitted from the laser module is small. Therefore, it is conceivable to oscillate a laser beam having a low light intensity from the laser element, but there is a limit to the oscillation of the laser beam having a low light intensity.

Further, the miniaturization of the laser module is progressing, and as a result, the light receiving element for feedback control of the laser element is also miniaturized. As the size of the light receiving element is reduced, the light receiving area becomes smaller. Therefore, for example, when a laser beam having a small light intensity is oscillated from the laser element, there is a concern that the detection accuracy of the laser beam may be lowered. A decrease in the detection accuracy of the laser beam may lead to a decrease in the accuracy of the feedback control of the laser element.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser projection device capable of emitting laser light having a low light intensity and suppressing a decrease in detection accuracy of a light receiving element.

The present invention is a glasses-shaped laser projection device provided with a vine, the laser module, a scanning optical member that scans a first laser beam emitted from the laser module, and the scanning optical member scanned by the scanning optical member. The laser module comprises a projection optical member that projects a laser beam onto the user's retina and projects an image onto the retina, and the laser module comprises three or more laser elements in which each light emitting point is located on a plane. The front surface where the plurality of laser elements are assembled and the laser light emitted by the plurality of laser elements is emitted to the outside on the surface intersecting the plane, and the plurality of laser elements emit the laser light. The laser having two sides parallel to the plane direction of the plane and having a symmetrical shape with respect to the plane and the laser assembled to the housing and oscillating the plurality of laser elements. An optical element that disperses light in the first direction and the second direction, and the amount of light of the first laser beam that disperses in the first direction is smaller than the amount of light of the second laser beam that disperses in the second direction. The laser module comprises a light receiving element that is assembled to the housing and receives the second laser light dispersed in the second direction by the optical element, and the laser module is mounted on either of the two side surfaces of the housing. It is a laser projection device fixed to the attachment portion of the vine.

In the above configuration, the first laser beam in each of the plurality of laser elements may be coaxially synthesized by the optical element.

In the above configuration, the plurality of laser elements oscillate the laser light in different wavelength bands, and the light receiving element has a plurality of light receiving regions having sensitivity in each of the wavelength bands of the laser light oscillated by the plurality of laser elements. It can be configured to be provided.

In the above configuration, the plurality of laser elements oscillate the laser light in different wavelength bands, and the light receiving element has one light receiving region having sensitivity in all the wavelength bands of the laser light oscillated by the plurality of laser elements. It can be configured to be provided.

In the above configuration, the laser beam oscillated by the plurality of laser elements may be incident on the optical element without passing through a lens.

In the above configuration, the second laser beam received by the light receiving element may be a divergent light.

In the above configuration, the projection optical member may be configured to project the beam-shaped first laser beam onto the retina and project the image onto the retina .

According to the present invention, it is possible to emit a laser beam having a low light intensity and suppress a decrease in the detection sensitivity of the light receiving element.

FIG. 1 is a diagram showing a configuration of a laser module according to the first embodiment. FIG. 2 is a view of the image projection device according to the second embodiment as viewed from above. 3A is a front view of the laser module, FIG. 3B is a side view of FIG. 3A as viewed from the A direction, and FIG. 3C is a side view of FIG. 3A from the B direction. It is a side view as seen. 4 (a) and 4 (b) are exploded perspective views of the laser module. FIG. 5 is a perspective view illustrating the assembly of the laser element to the housing. FIG. 6 is a diagram showing the focal point of the laser beam emitted from the laser module. FIG. 7 is an exploded perspective view of the laser module according to the modified example. 8 (a) to 8 (d) are plan views of the light receiving element.

Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a laser module according to the first embodiment. As shown in FIG. 1, the laser module 100 of the first embodiment includes a laser element 12, a dichroic prism 14, a light receiving element 20, and a control unit 21. The control unit 21 may be an external component without being included in the laser module 100.

The laser element 12 is, for example, a semiconductor laser diode and oscillates a laser beam 11. The laser beam 11 oscillated by the laser element 12 is incident on the dichroic prism 14, which is an optical element having a function of transmitting and reflecting the laser beam. The laser light 11 is a laser light (transmitted light) 13 that is transmitted through the dichroic prism 14 and travels in the first direction by the dichroic prism 14, and a laser light (reflected light) 15 that is reflected by the dichroic prism 14 and travels in the second direction. And, it is dispersed in.

The laser beam 13 transmitted through the dichroic prism 14 is emitted from the laser module 100 to the outside. The laser beam 15 reflected by the dichroic prism 14 is radiated to the light receiving element 20. The light receiving element 20 is an element that converts incident light such as a semiconductor photodiode into a current signal, and is arranged at a position where the laser light 15 is received.

The control unit 21 is a processor such as a CPU (Central Processing Unit). The control unit 21 controls the laser beam 11 oscillated by the laser element 12 by inputting an electric signal to the laser element 12. Further, the current (monitor value) output by the light receiving element 20 by photoelectric conversion is input to the control unit 21. The control unit 21 feedback-controls the laser element 12 based on the monitor value of the light receiving element 20.

When the laser module 100 is used in a laser projection device such as a retinal projection type image projection device that projects a laser beam having a low light intensity onto an object to be projected, the laser light 13 having a low light intensity (for example, on the order of μW) is used from the laser module 100. It is desirable that laser light) be emitted. Therefore, it is conceivable to reduce the light intensity of the laser beam 11 oscillated by the laser element 12. However, there is a limit to the oscillation of the laser beam 11 having a low light intensity (for example, about several mW), and it is difficult to stably oscillate the laser beam 11 having a light intensity lower than that.

Further, the size of the laser module 100 is being reduced, and as a result, the light receiving element 20 is also being miniaturized. As the size of the light receiving element 20 progresses, the light receiving area for receiving the laser beam 15 becomes smaller. Therefore, for example, when the laser element 12 oscillates the laser light 11 having a low light intensity such as several mW, the light receiving amount of the light receiving element 20 is, for example, several tens of μW, and the dark current changes due to the temperature change and the outside. There is a concern that the detection accuracy of the laser beam 15 may decrease due to the influence of light or the like. When the detection accuracy of the laser beam 15 is lowered, the feedback control of the laser element 12 by the control unit 21 becomes unstable, and it becomes difficult to oscillate the laser beam 11 having a stable light intensity from the laser element 12.

Therefore, in the first embodiment, a dichroic prism 14 having a spectral characteristic in which the amount of light of the laser light 13 is smaller than the amount of light of the laser light 15 is used for the dichroic prism 14 that disperses the laser light 11 into the laser light 13 and the laser light 15. For example, a dichroic prism 14 that disperses the laser beam 11 so that the amount of light of the laser beam 13 is 15% and the amount of light of the laser beam 15 is 85% is used. As a result, the laser light 13 having a smaller amount of light than the laser light 11 oscillated by the laser element 12 is emitted to the outside from the laser module 100, so that the laser light 11 is emitted to the outside while realizing stable oscillation of the laser light 11 by the laser element 12. The light intensity of the laser beam 13 to be generated can be reduced. Further, even when the size of the laser module 100 is reduced and the light receiving area of the light receiving element 20 is reduced, the laser light 15 having a light amount equal to or more than half that of the laser light 11 is radiated to the light receiving element 20, so that the light receiving element 20 is emitted. The amount of light of the laser beam 15 detected by is increased, and the deterioration of the detection accuracy can be suppressed. As described above, according to the first embodiment, it is possible to realize the emission of the laser beam 13 having a low light intensity and the suppression of deterioration of the detection accuracy of the light receiving element 20.

In Example 1, the case where the light amount of the laser light 13 is 15% of the laser light 11 and the light amount of the laser light 15 is 85% of the laser light 11 is shown as an example, but the case is not limited to this case. From the viewpoint of reducing the light intensity of the laser light emitted from the laser module 100 to the outside, the amount of light of the laser light 13 is preferably 30% or less, more preferably 20% or less, still more preferably 10% or less of the laser light 11. Further, from the viewpoint of improving the detection accuracy of the light receiving element 20, the amount of light of the laser light 15 is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more of the laser light 11.

In Example 1, the case of a dichroic prism has been described as an example of an optical element that transmits and reflects laser light, but other optical elements such as a plate-shaped dichroic mirror and a polarizing beam splitter may also be used. Further, the optical element has a configuration in which the laser light 11 is dispersed into the laser light 13 and the laser light 15 and also has a function of differentiating the light amount ratios of the laser light 13 and the laser light 15, but if the spectroscopy and the light amount ratio are different. The function of making the light may be performed by another member. That is, the optical element is composed of two types of members, a spectroscope and a dimming filter (ND filter). The same function can be realized by providing an ND filter on the side of the laser beam 13 to dimming the light. With this configuration, a spectroscope such as a dichroic prism can set a desired amount of light with an ND filter without having to set the spectral ratio precisely, so that versatility for spectroscopy and light amount control can be achieved. Can be enhanced.

FIG. 2 is a view of the image projection device according to the second embodiment as viewed from above. As shown in FIG. 2, the image projection device 500 includes a laser module 100a, a lens 60, a mirror 62, a scanning mirror 64, a projection mirror 66, an image input unit 68, and a control unit 70.

The image projection device 500 is a glasses type. The glasses have a pair of vines 72 and a pair of lenses 74. Each pair of vines 72 is provided with a laser module 100a, a lens 60, a mirror 62, and a scanning mirror 64. The laser module 100a is attached to each attachment portion 78 of the pair of vines 72. A projection mirror 66 is provided for each of the pair of lenses 74. The image input unit 68 and the control unit 70 may be provided on an external device (for example, a mobile terminal) without being provided on the glasses, or may be provided on the vine 72 of the glasses.

Image data is input to the image input unit 68 from a camera and / or a recording device (not shown). The control unit 70 controls the emission of the laser beam 76 from the laser module 100a based on the input image data. In this way, the image data is converted into the laser beam 76, which is an image ray, by the laser module 100a.

The control unit 70 is, for example, a control circuit, and may be a processor such as a CPU (Central Processing Unit) or a dedicated circuit. If the camera is placed at an appropriate position of the image projection device 500 toward the user's line-of-sight direction, the image in the line-of-sight direction captured by this camera can be projected onto the user's retina 82. Further, the image input from the recording device or the like is projected, or the camera image and the image from the recording device or the like are superimposed by the control unit 70 to project a so-called virtual reality (AR) image. You can also do it.

The lens 60 is a composite lens of a collimating lens and an objective lens, and converts the laser light 76 emitted from the laser module 100a into convergent light that slightly converges from the divergent light. The lens 60 may be integrally assembled with the laser module 100a, or may be a separate component from the laser module 100a.

The mirror 62 reflects the laser beam 76 that has passed through the lens 60 toward the scanning mirror 64. The scanning mirror 64 scans the laser beam 76 in a two-dimensional direction and uses it as projected light for projecting an image on the user's retina 82. The scanning mirror 64 is, for example, a MEMS (Micro Electro Mechanical System) mirror, and scans the laser beam 76 in two-dimensional directions in the horizontal direction and the vertical direction. In the second embodiment, the case of the scanning mirror 64 as the scanning optical member will be described as an example, but the scanning optical member may be capable of scanning the laser beam, for example, lithium niobate niobate (KTN) which is an electro-optical material. ) Other scanners such as crystals may be used.

The laser beam 76 scanned by the scanning mirror 64 is incident on the projection mirror 66 provided on the surface of the lens 74 of the glasses on the user's eyeball 80 side. The projection mirror 66 projects an image on the retina 82 by projecting the laser beam 76 scanned by the scanning mirror 64 onto the user's retina 82. The user recognizes the image by the afterimage effect of the laser beam 76 projected on the retina 82. Since the laser module 100a and the like are provided for each of the pair of vines 72 of the glasses, the user can recognize the image with both eyes.

The projection mirror 66 is designed so that the convergence position of the laser beam 76 scanned by the scanning mirror 64 is near the pupil 84. The projection mirror 66 does not have to be in contact with the lens 74 of the glasses, and may be in a position where the laser beam 76 can be projected onto the retina 82 through the pupil 84. Further, depending on the application, it is not necessary to provide the lens 74 only with the projection mirror 66. In the second embodiment, the case of the projection mirror 66 as the projection optical member will be described as an example, but the projection optical member may be any as long as it can project the laser beam onto the projected object such as the retina 82, for example, a diffraction grating or a lens. May be. When a lens is used as a projection optical member, it can be realized by arranging a mirror that does not collect light and arranging the lens on the eyeball 80 side of this mirror, and how to arrange an optical system such as a laser module 100a and a scanning mirror 64. Therefore, it is also possible to adopt a configuration in which the laser beam is projected onto the retina 82 with only the lens.

The laser beam 76 scanned by the scanning mirror 64 is focused in front of the projection mirror 66, becomes divergent light, and is incident on the projection mirror 66. As a result, the laser beam 76 is incident on the cornea 88 with substantially parallel light by the focusing power of the projection mirror 66, and is focused on the vicinity of the retina 82 by the crystalline lens 86.

3A is a front view of the laser module, FIG. 3B is a side view of FIG. 3A as viewed from the A direction, and FIG. 3C is a side view of FIG. 3A from the B direction. It is a side view as seen. As shown in FIGS. 3A to 3C, the laser module 100a includes a housing 10, laser elements 12a to 12c, dichroic prisms 14a and 14b, a mirror 16, a fixing portion 18, and a light receiving element. 20a, 20b, and so on. The width W of the housing 10 is, for example, about 4 mm, the height H is, for example, about 11 mm, and the depth D is, for example, about 16 mm.

The housing 10 is made of a metal having high thermal conductivity such as an aluminum alloy or a magnesium alloy. The housing 10 has a frame shape having a space 22 inside. The space 22 is formed so as to penetrate the housing 10 in the width direction from one side surface 42 to the other side surface 44. The front surface 40 of the housing 10 is provided with a hole 24 that communicates the space 22 with the outside, synthesizes laser light from the laser elements 12a to 12c, and emits the laser light to the outside.

The laser elements 12a to 12c are, for example, TO-CAN package type semiconductor laser diodes, and are assembled to the housing 10 so that the laser beam oscillates toward the space 22 provided in the housing 10. The laser element 12a is attached to the back surface 46 of the housing 10, and oscillates, for example, a red laser beam. The laser element 12b is attached to the upper surface 48 of the housing 10, and oscillates, for example, green laser light. The laser element 12c is assembled on the front surface 40 of the housing 10 above the hole 24, and oscillates, for example, a blue laser beam. For example, the wavelength of the red laser light is 610 nm to 660 nm, the wavelength of the green laser light is 515 nm to 540 nm, and the wavelength of the blue laser light is 440 nm to 460 nm.

The dichroic prisms 14a and 14b are optical elements having functions of transmitting, reflecting, and synthesizing laser light, and are located in the space 22 and assembled to the housing 10. For example, a red laser beam oscillated from the laser element 12a and, for example, a green laser light oscillated from the laser element 12b are incident on the dichroic prism 14a without passing through the lens. At this time, for example, the red laser light oscillated from the laser element 12a is separated into transmitted light and reflected light by the dichroic prism 14a. Further, for example, the green laser light oscillated from the laser element 12b is separated into transmitted light and reflected light by the dichroic prism 14a. The red laser light transmitted through the dichroic prism 14a and the green laser light reflected by the dichroic prism 14a are combined and substantially completely transmitted through the dichroic prism 14b and radiated to the hole 24 capable of emitting to the outside. For example, the blue laser light oscillated from the laser element 12c is substantially totally reflected by the mirror 16 and incident on the dichroic prism 14b without passing through the lens, and is dispersed into the transmitted light and the reflected light. The blue laser light reflected by the dichroic prism 14b is combined with the synthetic light synthesized by the dichroic prism 14a and radiated to the hole 24 capable of emitting to the outside. On the other hand, the red laser light reflected from the dichroic prism 14a and the green laser light transmitted through the dichroic prism 14a are radiated to the light receiving element 20a. Further, the blue laser light transmitted through the dichroic prism 14b is radiated to the light receiving element 20b.

The spectral characteristics of the dichroic prism 14a are such that the reflected red laser light has a higher light intensity than the transmitted red laser light, and the transmitted green laser light has higher light than the reflected green laser light. It is configured to be strong. That is, the dichroic prism 14a disperses the red laser light oscillated by the laser element 12a into transmitted light (laser light in the first direction) and reflected light (laser light in the second direction), and also transmits transmitted light (in the first direction). The amount of light (laser light) is made smaller than the amount of reflected light (laser light in the second direction). For example, the spectral characteristics of the red laser light of the dichroic prism 14a are transmission 15% and reflection 85%. Further, the dichroic prism 14a disperses the green laser light oscillated by the laser element 12b into transmitted light (laser light in the second direction) and reflected light (laser light in the first direction), and also reflects reflected light (laser light in the first direction). The amount of light (laser light) is made smaller than the amount of transmitted light (laser light in the second direction). For example, the spectral characteristics of the green laser light of the dichroic prism 14a are 15% reflection and 85% transmission.

The spectral characteristics of the dichroic prism 14b are configured so that the transmitted blue laser light has a higher light intensity than the reflected blue laser light. That is, the dichroic prism 14b disperses the blue laser light oscillated by the laser element 12c into transmitted light (laser light in the second direction) and reflected light (laser light in the first direction), and also reflects reflected light (laser light in the first direction). The amount of light (laser light) is made smaller than the amount of transmitted light (laser light in the second direction). For example, the spectral characteristics of the blue laser light of the dichroic prism 14b are 15% reflection and 85% transmission.

The case of a dichroic prism will be described as an example of an optical element that transmits, reflects, and synthesizes laser light, but other optical elements such as a plate-shaped dichroic mirror may also be used.

The laser elements 12a to 12c are assembled to the housing 10 so that the laser beam oscillates toward the space 22 provided inside the housing 10, and the dichroic prisms 14a and 14b are located in the space 22 and the housing 10 is located. The laser module 100a can be miniaturized by being assembled to the laser module 100a. As the laser module 100a becomes smaller, it becomes easier to attach the laser module 100a to the vine 72 of the glasses in the glasses-type image projection device 500.

The fixing portion 18 is provided on each of the pair of side surfaces 42 and 44 of the housing 10. The fixing portion 18 has a hole 26 penetrating the housing 10 from one side surface 42 of the housing 10 to the other side surface 44. The laser module 100a is fixed to an external component by passing a screw or the like through the hole 26 of the fixing portion 18. The fixed portion 18 is formed so as to be one step higher than the surroundings. That is, the fixing portion 18 provided on the side surface 42 of the housing 10 is formed one step higher than the region other than the fixing portion 18 of the side surface 42, and the fixing portion 18 provided on the side surface 44 of the housing 10 is fixed to the side surface 44. It is formed one step higher than the region other than the portion 18. As a result, when the laser module 100a is fixed to the external component, only the fixed portion 18 of the housing 10 comes into contact with the external component.

The light receiving elements 20a and 20b are, for example, semiconductor photodiodes, and are assembled to the lower surface 50 of the housing 10 on the outside of the housing 10. The light receiving element 20a is assembled at a position sandwiching the dichroic prism 14a and the housing 10, is oscillated by the laser element 12a and the laser element 12b, and receives the laser light dispersed in the second direction by the dichroic prism 14a. The light receiving element 20b is assembled at a position sandwiching the dichroic prism 14b and the housing 10, is oscillated by the laser element 12c, and receives the laser light dispersed in the second direction by the dichroic prism 14b. The current (monitor value) output by the light receiving elements 20a and 20b by photoelectric conversion is input to the control unit 70. The control unit 70 feedback-controls the laser elements 12a to 12c based on the monitor values of the light receiving elements 20a and 20b.

8 (a) to 8 (d) are plan views of the light receiving element. 8 (a) is a plan view of the light receiving element 20a, and FIG. 8 (b) is a plan view of the light receiving element 20b. As shown in FIG. 8A, the light receiving element 20a has a light receiving region 90 having sensitivity in the wavelength band of red laser light and receiving red laser light, and green having sensitivity in the wavelength band of green laser light. It is configured to have a light receiving region 92 that receives laser light. As shown in FIG. 8B, the light receiving element 20b is configured to have a light receiving region 94 that has sensitivity in the wavelength band of the blue laser light and receives the blue laser light. At this time, the light receiving regions 90 to 94 do not define the radiation range of the laser light, and the combined light of the red laser light and the green laser light is radiated into a predetermined range as shown by the alternate long and short dash line in FIG. 8A. To.

The red laser light may be totally transmitted through the dichroic prism 14a, the green laser light may be totally reflected by the dichroic prism 14a and synthesized, and the green laser light may be dispersed into the transmitted light and the reflected light by the dichroic prism 14b. In this case, the spectral characteristics of the dichroic prism 14b are configured so that the reflected synthetic light has a higher light intensity than the combined light of the transmitted red laser light and the green laser light, and the blue laser light is configured in the same manner as described above. Will be done. In this case, as shown in FIG. 8C, the light receiving element 20b has a light receiving region 90 having sensitivity in the wavelength band of red laser light, a light receiving region 92 having sensitivity in the wavelength band of green laser light, and a blue laser light. The light receiving element 20a is not required because it has a light receiving region 94 having sensitivity in the wavelength band of. Further, as shown in FIG. 8D, the light receiving element 20b has a light receiving region 95 that has sensitivity in all wavelength bands of red laser light, green laser light, and blue laser light and receives all laser light. The light receiving element 20b monitors the red laser light, the green laser light, and the blue laser light with the light receiving element 20b only during the time when the red laser light, the green laser light, and the blue laser light are emitted. The element 20a becomes unnecessary.

The laser elements 12a to 12c, the dichroic prisms 14a and 14b, the mirror 16, and the light receiving elements 20a and 20b are located between the side surfaces 42 and 44 of the housing 10 and are assembled to the housing 10.

4 (a) and 4 (b) are exploded perspective views of the laser module. FIG. 4A shows the housing 10 and the fixed portion 18, and FIG. 4B shows the laser elements 12a to 12c, the dichroic prisms 14a and 14b, the mirror 16, and the light receiving elements 20a and 20b. As shown in FIGS. 4A and 4B, the plane formed by the light emitting points 28 of the laser elements 12a to 12c is defined as the plane 30. The points where the flat surface 30 intersects with the housing 10, the dichroic prisms 14a, 14b, and the like are also indicated by the alternate long and short dash lines. The housing 10 has a symmetrical shape with respect to the flat surface 30. The front surface 40, the back surface 46, the upper surface 48, and the lower surface 50 of the housing 10 intersect the plane 30. That is, the center lines of the front surface 40, the back surface 46, the upper surface 48, and the lower surface 50 of the housing 10 coincide with the plane 30. The side surfaces 42 and 44 of the housing 10 are located on both sides of the plane 30, and are, for example, planes parallel to the plane 30. The fixing portions 18 provided on the side surfaces 42 and 44 of the housing 10 are provided symmetrically with respect to the plane 30. The dichroic prisms 14a and 14b, the mirror 16 and the light receiving elements 20a and 20b are assembled to the housing 10 in a symmetrical shape with respect to the plane 30.

That is, the side surfaces 42 and 44 provided with the fixing portion 18 are parallel to the emission direction of the laser beam, and the light emitting points 28 of the laser elements 12a to 12c are equidistant from the side surfaces 42 and 44, and the side surfaces 42 and 44 are equal. It is located in the center between and. Therefore, when the laser module 100a is attached to each attachment portion 78 of each pair of vines 72 as shown in FIG. 2, one side surface 42 of the laser module 100a is attached to one vine 72 and the other vine 72. The other side surface 44 of the other laser module 100a is attached, and the light emitting points 28 of the laser elements 12a to 12c of each laser module 100a are equidistant from the respective attachment portions 78.

As described above, the housing 10 has a symmetrical shape with respect to the plane 30 formed by the light emitting points 28 of the laser elements 12a to 12c. The fixing portion 18 is provided on the side surfaces 42 and 44 of the housing 10 symmetrically with respect to the plane 30. Thereby, the laser module 100a can be fixed to the external component by the fixing portion 18 on both the side surfaces 42 and 44 of the housing 10 in the same optical layout. Therefore, the laser module 100a can be fixed to any of the pair of vines 72 of the glasses-type image projection device 500 while the direction of the emitted laser light remains the direction of the projection mirror 66. Further, regardless of whether the laser module 100a is fixed to the external component by the fixing portion 18 of the side surface 42 or 44 of the housing 10, the housing 10 has a symmetrical shape with respect to the flat surface 30 and the fixed portion 18 is fixed to the flat surface 30. On the other hand, since they are provided symmetrically, the same heat dissipation can be obtained. The symmetrical shape of the housing 10 and the symmetrical arrangement of the fixed portion 18 are preferably a completely symmetrical shape and a completely symmetrical arrangement from the viewpoint of heat dissipation, but they have almost no effect on heat dissipation to the extent of manufacturing error. The shape and arrangement may differ to some extent.

The plane 30 formed by the light emitting points 28 of the laser elements 12a to 12c has the same distance to the fixed portion 18 of the side surface 42 and the distance to the fixed portion 18 of the side surface 44. As a result, when the fixing portion 18 of one side surface 42 of the housing 10 is fixed to the mounting portion 78 of one of the pair of vines 72, and the other of the housing 10 is fixed to the mounting portion 78 of the other vine. The distance from the mounting portion 78 of the light emitting point 28 of the laser elements 12a to 12c is the same as when the fixing portion 18 of the side surface 44 is fixed. Therefore, with this configuration, when the laser module 100a is attached to both of the pair of vines 72 of the image projection device 500, it can be attached symmetrically both thermally and optically. This makes it possible to attach the same laser module 100a to both the right eye and the left eye while minimizing the influence on the thermal and optical performance. Further, the image projection device 500 may be attached to only one of the vines 72 as the image projection device for one eye, and the laser module 100a may be attached to either the left or right vine 72. By having the property and enabling the same optical layout, it is possible to provide a laser module having a reduced manufacturing cost and an image projection device provided with the laser module.

Further, since the fixing portion 18 is higher than the region other than the region where the fixing portion 18 is provided on the side surfaces 42 and 44 of the housing 10, the laser module 100a is fixed to the external component by the fixing portion 18. In this case, only the fixing portion 18 of the side surfaces 42 and 44 comes into contact with the external component. Therefore, even if the laser module 100a is fixed to the external component by the fixing portion 18 of either the side surface 42 or 44 of the housing 10, the same heat dissipation can be obtained while minimizing the optical distortion due to the fixing. It will be easier.

Further, as shown in FIG. 4B, the dichroic prisms 14a and 14b, the mirror 16 and the light receiving elements 20a and 20b have a symmetrical shape with respect to the flat surface 30 and are assembled to the housing 10 so that the laser module can be used. When the 100a is fixed to the external component by either the fixing portion 18 of the side surface 42 or 44 of the housing 10, the same heat dissipation can be more easily obtained. Further, as shown in FIGS. 3A to 3C, the laser elements 12a to 12c, the dichroic prisms 14a and 14b, the mirror 16 and the light receiving elements 20a and 20b are located between the side surfaces 42 and 44 of the housing 10. By being positioned and assembled to the housing 10, the dichroic prisms 14a and 14b, the mirror 16 and the light receiving elements 20a and 20b can be easily assembled so as to have a symmetrical shape with respect to the plane 30.

FIG. 5 is a perspective view illustrating the assembly of the laser element to the housing. Before assembling the laser elements 12a to 12c to the housing 10, the dichroic prisms 14a and 14b and the mirror 16 are assembled to the housing 10. The laser elements 12a to 12c are in the X-axis direction (width direction of the housing 10), the Y-axis direction (height direction of the housing 10), and the Z-axis direction (depth direction of the housing 10) with respect to the housing 10. It is possible to move in parallel to the X-axis, Y-axis, and Z-axis. When the laser elements 12a to 12c are assembled to the housing 10, the laser light oscillated by the laser elements 12a to 12c is focused at the same position outside the laser module 100a by a lens arranged after the dichroic prism 14b. As described above, the laser elements 12a to 12c are moved in parallel and rotationally along the X-axis, Y-axis, and Z-axis to adjust the optical axis and focal length, and are fixed with an adhesive (not shown). The light receiving elements 20a and 20b may be fixed at the design position in advance on the lower surface 50 of the housing 10, or may be adjusted and fixed at the optimum position after the laser elements 12a to 12c are adjusted and fixed. When adjusting and fixing the light receiving elements 20a and 20b, the light receiving elements 20a and 20b are in the X-axis direction (width direction of the housing 10) and the Z-axis direction (depth of the housing 10) with respect to the lower surface 50 of the housing 10. It is possible to move in parallel in the direction), and the light receiving element can be adjusted to a more optimum position. The light intensity of the laser light oscillated by the laser elements 12a to 12c is controlled to an appropriate light intensity by the control unit 70 that has received the current signals from the light receiving elements 20a and 20b.

FIG. 6 is a diagram showing the focal point of the laser beam emitted from the laser module. As shown in FIG. 6, by moving the laser elements 12a to 12c in parallel and rotationally along the X-axis, Y-axis, and Z-axis to align the optical axes, the laser light oscillated by the laser elements 12a to 12c can be obtained. It is synthesized coaxially by the dichroic prisms 14a and 14b, and is focused at the same position outside the laser module 100a by the lens 60 arranged after the dichroic prism 14b to form one focal point 32. The focal point 32 corresponds to the point where the laser beam 76 collects light in the rear stage of the scanning mirror 64 and the front stage of the projection mirror 66 in FIG.

If the focal positions of the laser beams emitted from the laser elements 12a to 12c deviate from each other, the color reproducibility deteriorates and it becomes difficult to project a high-quality image. However, in the second embodiment, the laser light emitted from the laser elements 12a to 12c and passing through the dichroic prisms 14a and 14b is focused by the lens 60 at the same position outside the housing 10, so that the color reproducibility is deteriorated. Can be suppressed and a good quality image can be projected.

According to the second embodiment, the image projection device 500 has a laser beam in the first direction that emits the laser beam oscillated by the laser elements 12a to 12c to the outside and a laser beam in the second direction that is incident on the light receiving elements 20a and 20b. A laser module 100a having dichroic prisms 14a and 14b for spectroscopy is provided. The dichroic prisms 14a and 14b have spectral characteristics in which the amount of light emitted from the laser beam in the first direction emitted to the outside is smaller than the amount of light emitted from the laser beam in the second direction incident on the light receiving elements 20a and 20b. Therefore, as in the first embodiment, it is possible to realize the emission of the laser beam having a small light intensity and the suppression of the decrease in the detection sensitivity of the light receiving element.

As shown in FIG. 6, the laser elements 12a and 12b oscillate, and the laser light dispersed in the first direction emitted to the outside by the dichroic prism 14a is coaxially combined by the dichroic prism 14a. As a result, the laser light oscillated by the laser elements 12a and 12b can be easily focused at the same position by the lens 60, and a high-quality image in which deterioration of color reproducibility is suppressed can be projected.

The light receiving element may have a plurality of light receiving regions having sensitivity in each wavelength band of the laser light oscillated by each of the plurality of laser elements as shown in FIGS. 8 (a) and 8 (c). As in (d), one light receiving region having sensitivity in all wavelength bands of the laser light oscillated by each of the plurality of laser elements may be provided. In the case of FIGS. 8A and 8C, the cost of the module can be reduced by downsizing the module and reducing the number of parts, as compared with the case where a plurality of light receiving elements corresponding to each of the plurality of laser elements are mounted. can. It is also possible to feedback control the amount of light of a plurality of laser elements at the same time. On the other hand, when the laser light oscillated by each of the plurality of laser elements is received in one light receiving region as shown in FIG. 8 (d), the light amount of the plurality of laser elements cannot be feedback-controlled at the same time, but the light receiving element It is expected that the cost of the module will be reduced by simplifying the monitor circuit and reducing the number of parts.

As shown in FIG. 6, the laser light oscillated by the laser elements 12a to 12c is incident on the dichroic prisms 14a and 14b without passing through the lens. As described above, since the lens is not provided between the laser elements 12a to 12c and the dichroic prisms 14a and 14b, the laser module 100a can be miniaturized. That is, as shown in FIG. 6, since there is only one lens 60, it is possible to suppress aberrations and deterioration of color reproducibility when a plurality of lenses are used, and at the same time, the laser module 100a can be downsized. ing. Further, when the lens is not provided between the laser elements 12a to 12c and the dichroic prisms 14a and 14b, the laser light received by the light receiving elements 20a and 20b is divergent light. When the light receiving area of the light receiving elements 20a and 20b becomes smaller due to the miniaturization of the laser module 100a, the amount of light received by the light receiving elements 20a and 20b becomes smaller when the light receiving elements 20a and 20b receive the laser light of the divergent light. Therefore, when the laser light received by the light receiving elements 20a and 20b is divergent light, the dichroic prisms 14a and 14b for increasing the amount of the laser light dispersed on the light receiving elements 20a and 20b are used. Is preferable.

FIG. 7 is an exploded perspective view of the laser module according to the modified example. As shown in FIG. 7, in the modified example laser module 100b, a film 34 that suppresses the reflection of the laser light emitted from the laser elements 12a to 12c is provided on the side surfaces 42 and 44 of the housing 10. The film 34 is formed of, for example, an AR (Anti-Reflection) sheet obtained by laminating a dielectric material by vapor deposition or sputtering, a light absorbing sheet using a continuous fine porous resin, or the like. Since other configurations are the same as those of the laser module 100a, the description thereof will be omitted.

The film 34 may be provided on the side surfaces 42 and 44 of the housing 10. This makes it possible to suppress stray light of the laser light emitted from the laser elements 12a to 12c. In addition, the incident of light from the outside can be suppressed. The film 34 is flat on the side surfaces 42 and 44 of the housing 10 so that heat dissipation and suppression of stray light are comparable even when the film 34 is fixed to an external component by any of the fixing portions 18 of the side surfaces 42 and 44 of the housing 10. It is preferable that the shape is symmetrical with respect to 30.

In the image projection device 500 of the second embodiment, the case where the image is projected to both eyes is shown as an example, but the case where the image is projected to only one eye may be used. In this case, the laser module 100a or the like may be attached only to one of the vines 72. Further, although the case where the laser module 100a includes laser elements 12a to 12c that oscillate red, green, and blue laser light is shown as an example, three or more lasers that oscillate laser light in other wavelength bands are shown as an example. It may be provided with an element.

In Example 2, the case of a retinal projection type image projection device as an example of a laser projection device provided with a laser module has been shown as an example, but it is excited by an image projection device other than the retinal projection type or, for example, weak light other than the image projection device. It may be the case of other laser projection devices such as a sensing device that detects the fluorescent dye to be produced.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Housing 11, 13, 15 Laser light 12-12c Laser element 14-14b Dycroic prism 16 Mirror 18 Fixed part 20-20b Light receiving element 21 Control unit 22 Space 24, 26 Hole 28 Light emitting point 30 Flat 32 Focus 34 Film 40 Front 42, 44 Side 46 Back 48 Top 50 Bottom 60 Lens 62 Mirror 64 Scanning Mirror 66 Projection Mirror 68 Image Input 70 Control 72 Glasses Vine 74 Glasses Lens 76 Laser Light 78 Mounting 80 Eyes 82 Retina 84 Eyes 86 Lenses 88 Corneal 90-95 Light receiving area 100-100b Laser module 500 Image projection device

Claims (7)

A glasses-shaped laser projection device equipped with a vine.
Laser module and
A scanning optical member that scans the first laser beam emitted from the laser module, and
A projection optical member that projects the first laser beam scanned by the scanning optical member onto the user's retina and projects an image onto the retina.
The laser module is
Three or more laser elements, each of which has a light emitting point located on a plane,
The front surface where the plurality of laser elements are assembled and intersecting the plane where the laser light emitted by the plurality of laser elements is emitted to the outside, and the direction in which the plurality of laser elements emit the laser light. A housing having two sides parallel to the plane direction and having a symmetrical shape with respect to the plane.
The amount of light of the first laser beam, which is assembled to the housing and oscillates by the plurality of laser elements, is separated in the first direction and the second direction and is separated in the first direction is the second direction. An optical element that is smaller than the amount of light of the second laser beam that is split into
A light receiving element that is assembled to the housing and receives the second laser beam dispersed in the second direction by the optical element is provided.
The laser module is a laser projection device fixed to the attachment portion of the vine on either of the two sides of the housing. The laser projection device according to claim 1, wherein the first laser beam in each of the plurality of laser elements is coaxially synthesized by the optical element. The plurality of laser elements oscillate the laser light in different wavelength bands, respectively.
The laser projection device according to claim 1 or 2, wherein the light receiving element includes a plurality of light receiving regions having sensitivity in each of the wavelength bands of the laser light oscillated by the plurality of laser elements. The plurality of laser elements oscillate the laser light in different wavelength bands, respectively.
The laser projection device according to claim 1 or 2, wherein the light receiving element includes one light receiving region having sensitivity in all the wavelength bands of the laser light oscillated by the plurality of laser elements. The laser projection device according to any one of claims 1 to 4, wherein the laser light oscillated by the plurality of laser elements is incident on the optical element without passing through a lens. The laser projection device according to any one of claims 1 to 5, wherein the second laser beam received by the light receiving element is divergent light. The laser projection device according to any one of claims 1 to 6, wherein the projection optical member projects the beam-shaped first laser beam onto the retina and projects the image onto the retina.

Images