JP7563261B2 - Optical deflection element, image projection device, head-up display, laser headlamp, head-mounted display, object recognition device and moving body - Google Patents

Description

The present invention relates to an optical deflection element, an image projection device, a head-up display, a laser headlamp, a head-mounted display, an object recognition device, and a moving object.

Conventionally, optical deflection elements manufactured using microelectromechanical system (MEMS) technology are known. Optical deflection elements used in image measurement sensors, distance sensors, and the like are required to have a larger mirror portion, a wider deflection angle, and higher reflectivity in order to scan light over a wider range.

However, when the mirror part of the optical deflection element is enlarged, the deflection angle is increased, and high-speed operation is performed, there is a possibility that the mirror part may be subjected to a large amount of environmental load (e.g., concentration of humidity and moisture), deformation of the shape, and stress concentration.

In general, optical deflection elements are made of materials that corrode when exposed to moisture. Therefore, Patent Document 1 discloses a technology for forming a protective film on the actuator section to protect against moisture.

However, when the object to be protected by the protective film is the reflective portion of the optical deflection element, the technology disclosed in Patent Document 1 cannot prevent moisture from entering from the end of the protective film portion, and there is a concern that the reflective film portion may corrode, increasing the chance of a decrease in reflectance and a decrease in functionality, thereby reducing the reliability of the optical deflection element.

The present invention has been made in consideration of the above, and aims to improve the reliability of the optical deflection element by increasing the moisture resistance of the reflecting portion.

To solve the above-mentioned problems and achieve the object, the present invention is characterized by comprising a reflecting section, a base supporting the reflecting section, a deforming section arranged to surround the outer periphery of the reflecting section in an area outside the area of the base where the reflecting section is provided and formed in at least one of a protruding or recessed shape from the surface where the reflecting section is provided, and a protective section covering the reflecting section and the deforming section to protect the reflecting section.

The present invention has the effect of improving the reliability of the optical deflection element by improving the moisture resistance of the reflecting portion.

FIG. 1 is a plan view illustrating an example of a configuration of a movable device according to a first embodiment. FIG. 2 is a cross-sectional view showing an example of the configuration of a movable device. FIG. 3 is a plan view showing a modified example of the configuration of the movable device. FIG. 4 is an enlarged plan view showing an example of a mirror portion. FIG. 5 is a cross-sectional view showing an example of a mirror portion. FIG. 6 is a plan view showing another example of the mirror portion. FIG. 7 is a cross-sectional view showing another example of the mirror portion. FIG. 8 is a cross-sectional view showing a modified example of the groove. FIG. 9 is a cross-sectional view showing a modified example of the deformation portion. FIG. 10 is a schematic diagram illustrating an example of an optical scanning system according to the second embodiment. FIG. 11 is a diagram illustrating a hardware configuration of an example of an optical scanning system. FIG. 12 is a functional block diagram of an example of a control device. FIG. 13 is a flowchart of an example of a process related to the optical scanning system. FIG. 14 is a schematic diagram showing an example of an automobile equipped with a head-up display device according to the third embodiment. FIG. 15 is a schematic diagram showing an example of a head-up display device. FIG. 16 is a schematic diagram showing an example of an image forming apparatus incorporating an optical writing device according to the fourth embodiment. FIG. 17 is a schematic diagram showing an example of an optical writing device. FIG. 18 is a schematic diagram showing an example of an automobile equipped with a lidar device according to the fifth embodiment. FIG. 19 is a schematic diagram illustrating an example of a lidar device. FIG. 20 is a schematic diagram showing an example of the configuration of a laser headlamp according to the sixth embodiment. FIG. 21 is a perspective view illustrating an external appearance of an HMD according to the seventh embodiment. FIG. 22 is a diagram illustrating a portion of the configuration of an HMD.

The following describes in detail embodiments of an optical deflection element, an image projection device, a head-up display, a laser headlamp, a head-mounted display, an object recognition device, and a moving body with reference to the attached drawings.

[First embodiment]
1 is a plan view showing an example of the configuration of a movable device 13 according to the first embodiment, and FIG. 2 is a cross-sectional view showing an example of the configuration of the movable device 13. As shown in FIG.

As shown in FIG. 1, the movable device 13, which is an optical deflection element, has a mirror section 101, first drive sections 110a and 110b, a first support section 120, second drive sections 130a and 130b, a second support section 140, and an electrode connection section 150.

The mirror unit 101 reflects incident light. The first driving units 110a and 110b are connected to the mirror unit 101 and drive the mirror unit 101 around a first axis parallel to the Y axis. The first support unit 120 supports the mirror unit 101 and the first driving units 110a and 110b.

The second driving units 130a and 130b are connected to the first support unit 120 and drive the mirror unit 101 and the first support unit 120 around a second axis parallel to the X-axis. The second support unit 140 supports the second driving unit.

The electrode connection unit 150 is electrically connected to the first drive units 110a, 110b, the second drive units 130a, 130b, and the control device 11 (see, for example, FIG. 10).

The movable device 13 is formed, for example, by forming a single SOI (Silicon On Insulator) substrate by etching or the like, and then forming the reflective film section 14, first piezoelectric drive sections 112a, 112b, second piezoelectric drive sections 131a-131f, 132a-132f, electrode connection section 150, etc. on the formed substrate, so that each component is integrally formed. Note that the formation of each of the above components may be performed after forming the SOI substrate, or may be performed while forming the SOI substrate.

As shown in FIG. 2, an SOI substrate is a substrate in which a silicon oxide layer 362 is provided on a first silicon layer made of single crystal silicon (Si), and a second silicon layer made of single crystal silicon is further provided on the silicon oxide layer. Hereinafter, the first silicon layer is referred to as silicon support layer 361, and the second silicon layer is referred to as silicon active layer 363.

Since the silicon active layer 363 has a smaller thickness in the Z-axis direction than in the X-axis direction or the Y-axis direction, a member consisting only of the silicon active layer 363 functions as an elastic part.

The SOI substrate does not necessarily have to be planar, and may have curvature, etc. Also, the material used to form the movable device 13 is not limited to the SOI substrate, as long as it can be integrally molded by etching or the like and can be made partially elastic.

The mirror section 101 is composed of, for example, a circular mirror section base 102 and a reflective film section 14, which is a reflective section formed on the +Z side surface of the mirror section base 102. The mirror section base 102 is composed of, for example, a silicon active layer 363. The reflective film section 14 is composed of, for example, a metal thin film containing aluminum, gold, silver, etc. The metal thin film may be a single layer or a multilayer. In addition, a functional film composed of a material different from the metal thin film, such as an enhanced reflection film, may be formed on the metal thin film. The mirror section 101 may have a rib formed on the -Z side surface of the mirror section base 102 to reinforce the mirror section. The rib is composed of, for example, a silicon support layer 361 and a silicon oxide layer 362, and can suppress distortion of the reflective film section 14 caused by movement.

The first driving units 110a and 110b are composed of two torsion bars 111a and 112b, each of which has one end connected to the mirror base 102 and extends in the first axial direction to movably support the mirror unit 101, and first piezoelectric driving units 112a and 112b, each of which has one end connected to the torsion bar and the other end connected to the inner circumference of the first support unit.

As shown in FIG. 2, the torsion bars 111a and 111b are composed of a silicon active layer 363. The first piezoelectric driving units 112a and 112b are composed of a lower electrode 201, a piezoelectric unit 202, and an upper electrode 203, which are formed in this order on the +Z side surface of the silicon active layer 363, which is the elastic unit. The upper electrode 203 and the lower electrode 201 are composed of, for example, gold (Au) or platinum (Pt). The piezoelectric unit 202 is composed of, for example, PZT (lead zirconate titanate), which is a piezoelectric material.

Returning to FIG. 1, the first support section 120 is a rectangular support member that is composed of, for example, a silicon support layer 361, a silicon oxide layer 362, and a silicon active layer 363, and is formed to surround the mirror section 101.

The second drive units 130a and 130b are composed of, for example, a plurality of second piezoelectric drive units 131a to 131f, 132a to 132f that are connected in a folded manner, and one end of the second drive units 130a and 130b is connected to the outer periphery of the first support unit 120, and the other end is connected to the inner periphery of the second support unit 140. At this time, the connection point between the second drive unit 130a and the first support unit 120 and the connection point between the second drive unit 130b and the first support unit 120, as well as the connection point between the second drive unit 130a and the second support unit 140 and the connection point between the second drive unit 130b and the second support unit 140, are point-symmetrical with respect to the center of the reflective film unit 14.

As shown in FIG. 2, the second driving units 130a and 130b are configured by forming a lower electrode 201, a piezoelectric unit 202, and an upper electrode 203 in this order on the +Z side surface of the silicon active layer 363, which is the elastic unit. The upper electrode 203 and the lower electrode 201 are made of, for example, gold (Au) or platinum (Pt). The piezoelectric unit 202 is made of, for example, PZT (lead zirconate titanate), which is a piezoelectric material.

Returning to FIG. 1, the second support unit 140 is a rectangular support member that is composed of, for example, a silicon support layer 361, a silicon oxide layer 362, and a silicon active layer 363, and is formed to surround the mirror unit 101, the first drive units 110a and 110b, the first support unit 120, and the second drive units 130a and 130b.

The electrode connection part 150 is formed, for example, on the +Z side surface of the second support part 140, and is electrically connected to the upper electrodes 203 and lower electrodes 201 of the first piezoelectric drive parts 112a, 112b, the second piezoelectric drive parts 131a to 131f, and the control device 11 via electrode wiring such as aluminum (Al). Note that the upper electrodes 203 or the lower electrodes 201 may each be directly connected to the electrode connection part, or may be indirectly connected by connecting the electrodes to each other, etc.

In this embodiment, the piezoelectric portion 202 is formed only on one surface (the surface on the +Z side) of the silicon active layer 363, which is the elastic portion, as an example. However, the piezoelectric portion 202 may be provided on another surface (for example, the surface on the -Z side) of the elastic portion, or may be provided on both one surface and the other surface of the elastic portion.

In addition, as long as the mirror unit 101 can be driven around the first axis or the second axis, the shape of each component is not limited to the shape of the embodiment. For example, the torsion bars 111a, 111b and the first piezoelectric drive units 112a, 112b may have a shape with a curvature.

Furthermore, an insulating layer made of a silicon oxide film may be formed on at least one of the +Z side surface of the upper electrode 203 of the first driving unit 110a, 110b, the +Z side surface of the first support unit, the +Z side surface of the upper electrode 203 of the second driving unit 130a, 130b, and the +Z side surface of the second support unit. In this case, electrode wiring is provided on the insulating layer, and the insulating layer is partially removed or not formed as an opening only at the connection spot where the upper electrode 203 or the lower electrode 201 is connected to the electrode wiring, thereby increasing the design freedom of the first driving unit 110a, 110b, the second driving unit 130a, 130b, and the electrode wiring, and further suppressing short circuits due to contact between the electrodes. In addition, the silicon oxide film also functions as an anti-reflective material.

[Details of control of the control device]
Next, details of the control by the control device that drives the first drive units 110a, 110b and the second drive units 130a, 130b of the movable device 13 will be described.

When a positive or negative voltage is applied in the polarization direction, the piezoelectric section 202 of the first driving section 110a, 110b and the second driving section 130a, 130b undergoes deformation (e.g., expansion and contraction) proportional to the potential of the applied voltage, thereby exerting the so-called inverse piezoelectric effect. The first driving section 110a, 110b and the second driving section 130a, 130b use the inverse piezoelectric effect to move the mirror section 101.

In this case, the angle formed by the XY plane and the reflective film portion 14 when the reflective film portion 14 of the mirror portion 101 is tilted in the +Z direction or the -Z direction with respect to the XY plane is called the deflection angle. In this case, the +Z direction is the positive deflection angle, and the -Z direction is the negative deflection angle.

First, we will explain the control of the control device that drives the first drive units 110a and 110b.

In the first driving units 110a and 110b, when a driving voltage is applied in parallel to the piezoelectric units 202 of the first piezoelectric driving units 112a and 112b via the upper electrode 203 and the lower electrode 201, each piezoelectric unit 202 is deformed. The deformation of the piezoelectric units 202 causes the first piezoelectric driving units 112a and 112b to bend and deform. As a result, a driving force about the first axis acts on the mirror unit 101 via the twisting of the two torsion bars 111a and 111b, and the mirror unit 101 moves about the first axis. The driving voltage applied to the first driving units 110a and 110b is controlled by the control device 11.

Therefore, the control device 11 can apply a predetermined sinusoidal drive voltage in parallel to the first piezoelectric drive units 112a and 112b of the first drive units 110a and 110b, thereby moving the mirror unit 101 around the first axis at a period of the predetermined sinusoidal drive voltage.

In particular, for example, when the frequency of the sinusoidal voltage is set to approximately 20 kHz, which is similar to the resonant frequency of the torsion bars 111a and 111b, the mirror portion 101 can be made to resonate at approximately 20 kHz by utilizing the mechanical resonance caused by the twisting of the torsion bars 111a and 111b.

In this embodiment, as shown in FIG. 1, the movable device 13 is a cantilever type movable device 13 in which the first piezoelectric drive units 112a and 112b extend from the torsion bars 111a and 111b in the +X direction, but the configuration is not limited to this as long as the reflective film unit 14 is moved by the piezoelectric unit to which a voltage is applied. FIG. 3 is a plan view showing a modified configuration of the movable device 13. For example, as shown in FIG. 3, a movable device 13a of a double-supported type having first piezoelectric drive units 212a and 212b extending from the torsion bars 211a and 211b in the +X direction and first piezoelectric drive units 212c and 212d extending in the -X direction may be used as the movable device. In addition, the movable device 13 may be configured to move the reflective film unit 14 in only one axial direction.

Next, the mirror unit 101 will be described in detail.

Here, FIG. 4 is a plan view showing an enlarged example of the mirror section 101, and FIG. 5 is a cross-sectional view showing an example of the mirror section 101. As shown in FIGS. 4 and 5, the mirror section 101 of this embodiment includes a reflective film section 14, a mirror section base 102 that supports the reflective film section 14, and a protective film section 141 that can protect the reflective film section 14.

The mirror section base 102 of the mirror section 101 is formed from a silicon active layer 363. However, this is not limited to this, and the mirror section base 102 of the mirror section 101 may be made of an oxide material, an inorganic material, an organic material, or the like. In addition, a reinforcing rib or other structure may be provided on the negative Z-direction surface of the mirror section base 102 of the mirror section 101. The rib or other structure is formed from a silicon support layer 361 and a silicon oxide layer 362, etc.

As shown in Figures 4 and 5, the mirror section 101 forms a reflective film section 14 on the positive Z-direction surface of the mirror section base 102 of the mirror section 101. The reflective film section 14 uses a metal thin film containing aluminum, gold, silver, etc., or a multi-layer film thereof. The metal thin film may be a single layer or a multi-layer. In addition, a functional film made of a material different from the metal thin film, such as an increased reflection film, may be formed on the metal thin film.

The example shown in FIG. 4 is an example in which the shape of the mirror base 102 of the mirror 101 is circular. In addition, the reflective film 14 is formed in a circular shape to match the mirror base 102.

The shape of the mirror base 102 of the mirror section 101 is not limited to this. Here, FIG. 6 is a plan view showing another example of the mirror section 101. For example, as shown in FIG. 6, the shape of the mirror base 102 of the mirror section 101 may be formed into a rectangular shape. In the example shown in FIG. 6(a), the reflective film section 14 is formed into a rectangular shape to match the mirror base 102. In the example shown in FIG. 6(b), the mirror base 102 of the mirror section 101 is formed into a rectangular shape, and the reflective film section 14 is formed into a circular shape similar to the example shown in FIG. 4.

As shown in Figures 4 and 6, the reflective film portion 14 of the mirror portion 101 is formed in a circular or rectangular shape, but is not limited to this and may be in other shapes.

However, in conventional mirrors, the need for wider reflection requires an increase in the area of the mirror, a wider driving range, and faster driving speeds, which increases the chances of vibration and torsional moment occurring, and this can cause tiny water molecules to get in between the base and protective film of the mirror reflector and penetrate into the reflector.

Therefore, as shown in Figs. 4 and 5, the mirror section 101 of this embodiment forms a groove 142, which is a deformed portion that has an opening on the surface where the reflecting section is provided, in an area outside the area where the reflecting section is provided in the mirror section base 102. The groove 142 is arranged so as to surround the outer periphery of the reflecting section. Note that the groove 142 may be configured to be divided into multiple parts by cuts, but it is preferable to arrange it in a ring shape so as to surround the reflecting section without cuts, as this can further reduce the opportunity for moisture to enter the reflecting film section 14. The shape of the groove 142 is not particularly limited, and in addition to the shape with curvature shown in Fig. 4, it may be linear or have a meandering structure. The groove 142 is formed in the active layer of the mirror section base 102 of the mirror section 101.

The groove 142 is provided in a layer that is negative in the Z direction from the reflective film 14. As shown in FIG. 5, the distance c from the end of the mirror base 102 of the mirror 101 is c>0. The width b of the groove 142 is formed to be about 10 μm. The depth d of the groove 142 is formed to be about 10 μm. From the viewpoint of the fracture strength of the structure, the opening degree of the groove 142 is preferably 0 to 10% or less of the cross-sectional area when there is no groove. As shown in FIG. 5, the shape of the groove 142 is intended to suppress the creeping up of infiltrated moisture, and it is preferable that the depth d and width b in the Z direction are the same.

The reflective film 14 may cover part of the groove 142, but does not completely cover the groove 142.

In this embodiment, the mirror section 101 has a protective film section 141 formed at least on the upper part of the reflective film section 14 in the Z direction and on the side and bottom of the groove section 142. The protective film section 141 conformally covers the sidewalls and bottom of the groove section 142 along the sidewalls and bottom. The reflective film section 14 may also cover up to the end of the mirror section base 102 of the mirror section 101. This makes it difficult for the protective film section 141 to peel off.

The protective film portion 141 is formed of Al2O3 (alumina) with known moisture-proofing properties by ALD (atomic layer deposition) deposition, which utilizes the self-controlling properties of atoms and can obtain ping-pong-free and step coverage. This forms a good protective film portion 141 along the sidewalls and bottom of the groove portion 142. However, the protective film portion 141 is not limited to this, and may be other inorganic or organic moisture-resistant films, multilayer films, coating-type fluorine-based resin materials, etc.

The mirror section 101 of this embodiment is configured in this way, so that if cracks or peeling occurs at the end of the protective film section 141 due to environmental load, moisture that has entered from the end of the protective film section 141 can seep into the protective film section 141 along the groove section 142. The mirror section 101 of this embodiment can make the path for moisture from the end of the protective film section 141 to the reflective film section 14 longer than in the past, thereby achieving the effect of suppressing the propagation of moisture to the reflective film section 14.

In this way, according to this embodiment, the opportunity for moisture to enter the reflective film portion 14 due to environmental load is reduced, and the moisture resistance of the reflective film portion 14 is improved, thereby improving the reliability of the optical deflection element.

As described above, according to this embodiment, by improving the reliability of the optical deflection element, the reflectance can be maintained, and the image quality does not deteriorate even with long-term use. Furthermore, according to this embodiment, performance can be maintained for a long period of time, and it can be used in situations with high environmental loads.

In the mirror section 101 of this embodiment, one groove 142 is formed in the mirror section base 102 to ensure a sufficient area of the reflective film section 14, but the number of grooves 142 in the mirror section 101 is not limited to this. Here, FIG. 7 is a cross-sectional view showing another example of the mirror section 101. For example, the mirror section 101 shown in FIG. 7 has two grooves 142 formed in the mirror section base 102, provided that a sufficient area of the reflective film section 14 can be ensured. In this way, if a sufficient area of the reflective film section 14 can be ensured, the mirror section 101 may have multiple grooves 142 in the mirror section base 102. According to the modified example of the groove 142 shown in FIG. 7, the path of moisture from the end of the protective film section 141 to the reflective film section 14 can be made longer than the groove 142 shown in FIG. 5, thereby further suppressing the propagation of moisture to the reflective film section 14.

In addition, the mirror unit 101 of this embodiment shows a groove 142 having the same depth d and width b in the Z direction as shown in FIG. 5 as a deformation part, but is not limited to this. Here, FIG. 8 is a cross-sectional view showing a modified example of the groove 142. FIG. 8(a) shows a groove 142 having a cross section with a shape in which the opening width e of the groove and the width f of the bottom are different lengths. FIG. 8(b) shows a groove 142 having a trapezoidal cross section with a groove opening width g and a bottom width h of different lengths. Note that FIG. 8(b) shows a groove 142 having an inverse tapered cross section in which the width of the groove tapers from bottom to top, but the groove 142 may have a tapered cross section in which the width of the groove tapers from top to bottom. FIG. 8(c) shows a groove 142 having a cross section in which one end of the outer periphery of a circular shape is cut. According to the modified example of the groove portion 142 shown in FIG. 8, the path for moisture from the end of the protective film portion 141 to the reflective film portion 14 can be made longer than that of the groove portion 142 shown in FIG. 5, thereby further suppressing the propagation of moisture to the reflective film portion 14.

Furthermore, in the mirror section 101 of this embodiment, the deformation section is shown as a groove section 142 provided in a layer negative in the Z direction from the reflective film section 14, but this is not limited to this. Here, FIG. 9 is a cross-sectional view showing a modified example of the deformation section. As shown in FIG. 9, the deformation section may be at least one or more convex sections 143 provided protruding in the positive Z direction from the reflective film section 14. According to the modified example shown in FIG. 9, the path for moisture from the end of the protective film section 141 to the reflective film section 14 can be made longer than in the conventional case, thereby further suppressing the propagation of moisture to the reflective film section 14.

In addition, the mirror portion 101 of this embodiment may have both the groove portion 142 and the convex portion 143 as the deformation portion.

Second Embodiment
Next, an optical scanning system according to a second embodiment will be described.

The second embodiment is an example of an optical scanning system equipped with the movable device 13 of the first embodiment described above.

Fig. 10 is a schematic diagram showing an example of an optical scanning system 10 according to the second embodiment. As shown in Fig. 10, the optical scanning system 10 is a system that deflects light irradiated from a light source device 12 by a reflective film portion 14 of a movable device 13 under the control of a control device 11 to optically scan a scanned surface 15.

The optical scanning system 10 is composed of a control device 11, a light source device 12, and a movable device 13 having a reflective film section 14.

The control device 11 is, for example, an electronic circuit unit including a CPU (Central Processing Unit) and an FPGA (Field-Programmable Gate Array). The movable device 13 is, for example, a MEMS (Micro Electromechanical Systems) device that has a reflective film portion 14 and can move the reflective film portion 14. The light source device 12 is, for example, a laser device that irradiates a laser. The scanned surface 15 is, for example, a screen.

The control device 11 generates control commands for the light source device 12 and the movable device 13 based on the acquired optical scanning information, and outputs drive signals to the light source device 12 and the movable device 13 based on the control commands.

The light source device 12 emits light based on the input drive signal. The movable device 13 moves the reflective film portion 14 in at least one axial direction or two axial directions based on the input drive signal.

As a result, for example, by controlling the control device 11 based on image information, which is an example of optical scanning information, the reflective film portion 14 of the movable device 13 can be moved back and forth in two axial directions within a predetermined range, and the irradiation light from the light source device 12 that is incident on the reflective film portion 14 can be deflected around one axis to perform optical scanning, thereby projecting any image onto the scanned surface 15. Details of the movable device of this embodiment and the control by the control device will be described later.

Next, the hardware configuration of an example of the optical scanning system 10 will be described with reference to FIG. 11. FIG. 11 is a hardware configuration diagram of an example of the optical scanning system 10. As shown in FIG. 11, the optical scanning system 10 includes a control device 11, a light source device 12, and a movable device 13, which are electrically connected to each other. Of these, the control device 11 includes a CPU 20, a RAM 21 (Random Access Memory), a ROM 22 (Read Only Memory), an FPGA 23, an external I/F 24, a light source device driver 25, and a movable device driver 26.

The CPU 20 is a calculation device that reads programs and data from storage devices such as the ROM 22 onto the RAM 21, executes processing, and realizes the overall control and functions of the control device 11.

RAM21 is a volatile storage device that temporarily stores programs and data.

The ROM 22 is a non-volatile storage device that can retain programs and data even when the power is turned off, and stores the processing programs and data that the CPU 20 executes to control each function of the optical scanning system 10.

The FPGA 23 is a circuit that outputs control signals suitable for the light source device driver 25 and the movable device driver 26 according to the processing of the CPU 20.

The external I/F 24 is, for example, an interface with an external device or a network. Examples of external devices include higher-level devices such as a PC (Personal Computer), and storage devices such as USB memory, SD cards, CDs, DVDs, HDDs, and SSDs. Examples of networks include an automobile's CAN (Controller Area Network) or LAN (Local Area Network), the Internet, etc. The external I/F 24 may have any configuration that enables connection or communication with an external device, and an external I/F 24 may be provided for each external device.

The light source device driver is an electric circuit that outputs a drive signal, such as a drive voltage, to the light source device 12 in accordance with an input control signal.

The movable device driver 26 is an electrical circuit that outputs a drive signal, such as a drive voltage, to the movable device 13 according to the input control signal.

In the control device 11, the CPU 20 acquires optical scanning information from an external device or a network via the external I/F 24. Any configuration is acceptable as long as the CPU 20 is capable of acquiring optical scanning information, and the optical scanning information may be stored in the ROM 22 or FPGA 23 in the control device 11, or a new storage device such as an SSD may be provided in the control device 11 and the optical scanning information may be stored in that storage device.

Here, the optical scanning information is information that indicates how to optically scan the scanned surface 15. For example, when an image is displayed by optical scanning, the optical scanning information is image data. Also, for example, when optical writing is performed by optical scanning, the optical scanning information is writing data that indicates the writing order and writing locations. In addition, for example, when object recognition is performed by optical scanning, the optical scanning information is irradiation data that indicates the timing and irradiation range of irradiating light for object recognition.

The control device 11 can realize the functional configuration described below by using instructions from the CPU 20 and the hardware configuration shown in FIG. 2.

Next, the functional configuration of the control device 11 of the optical scanning system 10 will be described with reference to FIG. 12. FIG. 12 is a functional block diagram of an example of the control device 11 of the optical scanning system 10.

As shown in FIG. 12, the control device 11 has the functions of a control unit 30 and a drive signal output unit 31.

The control unit 30 is realized by, for example, the CPU 20, FPGA 23, etc., and acquires optical scanning information from an external device, converts the optical scanning information into a control signal, and outputs it to the drive signal output unit 31. For example, the control unit 30 acquires image data from an external device, etc. as optical scanning information, generates a control signal from the image data by performing a predetermined process, and outputs it to the drive signal output unit 31. The drive signal output unit 31 is realized by the light source device driver 25, movable device driver 26, etc., and outputs a drive signal to the light source device 12 or movable device 13 based on the input control signal.

The drive signal is a signal for controlling the drive of the light source device 12 or the movable device 13. For example, in the light source device 12, it is a drive voltage that controls the timing and intensity of the light source irradiation. Also, for example, in the movable device 13, it is a drive voltage that controls the timing and range of movement of the reflective film portion 14 of the movable device 13.

Next, the process of optically scanning the surface 15 to be scanned by the optical scanning system 10 will be described with reference to FIG. 13. FIG. 13 is a flowchart of an example of the process related to the optical scanning system 10.

In step S11, the control unit 30 acquires optical scanning information from an external device, etc.

In step S12, the control unit 30 generates a control signal from the acquired optical scanning information and outputs the control signal to the drive signal output unit 31.

In step S13, the drive signal output unit 31 outputs a drive signal to the light source device 12 and the movable device 13 based on the input control signal.

In step 14, the light source device 12 emits light based on the input drive signal. The movable device 13 moves the reflective film portion 14 based on the input drive signal. By driving the light source device 12 and the movable device 13, the light is deflected in any direction and optically scanned.

In the optical scanning system 10, one control device 11 has the devices and functions to control the light source device 12 and the movable device 13, but the control device for the light source device and the control device for the movable device may be provided separately.

In addition, in the optical scanning system 10, one control device 11 is provided with the functions of the control unit 30 of the light source device 12 and the movable device 13 and the function of the drive signal output unit 31, but these functions may exist separately, for example, a drive signal output device having a drive signal output unit 31 may be provided separately from the control device 11 having the control unit 30. Note that, among the optical scanning system 10, the movable device 13 having the reflective film unit 14 and the control device 11 may form an optical deflection system that performs optical deflection.

[Third embodiment]
Next, an image projection device according to a third embodiment will be described.

The third embodiment is an example of an image projection device that uses the movable device 13 of the first embodiment described above.

Fig. 14 is a schematic diagram showing an example of an automobile 400 equipped with a head-up display device 500 according to the third embodiment. Fig. 15 is a schematic diagram showing an example of a head-up display device 500.

The image projection device is a device that projects an image by optical scanning, such as a head-up display device 500.

As shown in FIG. 14, the head-up display device 500 is installed, for example, near the windshield (windshield 401, etc.) of an automobile 400, which is a moving body. Projection light L emitted from the head-up display device 500 is reflected by the windshield 401 and directed toward the observer (driver 402), who is the user. This allows the driver 402 to view the image projected by the head-up display device 500 as a virtual image. Note that a combiner may be installed on the inner wall surface of the windshield, and the user may view a virtual image by the projected light reflected by the combiner.

As shown in FIG. 15, in the head-up display device 500, laser light is emitted from red, green, and blue laser light sources 501R, 501G, and 501B. The emitted laser light passes through an incidence optical system consisting of collimator lenses 502, 503, and 504 provided for each laser light source, two dichroic mirrors 505 and 506, and a light amount adjustment unit 507, and is then deflected by a movable device 13 having a reflective film unit 14. The deflected laser light then passes through a projection optical system consisting of a free-form surface mirror 509, an intermediate screen 510, and a projection mirror 511, and is projected onto a screen. In the head-up display device 500, the laser light sources 501R, 501G, and 501B, the collimator lenses 502, 503, and 504, and the dichroic mirrors 505 and 506 are unitized by an optical housing as a light source unit 530.

The head-up display device 500 projects an intermediate image displayed on an intermediate screen 510 onto the windshield 401 of the automobile 400, allowing the driver 402 to view the intermediate image as a virtual image.

The laser light of each color emitted from the laser light sources 501R, 501G, and 501B is converted into approximately parallel light by collimator lenses 502, 503, and 504, respectively, and then combined by two dichroic mirrors 505 and 506. The combined laser light has its light amount adjusted by a light amount adjustment unit 507, and is then two-dimensionally scanned by a movable device 13 having a reflective film unit 14. The projection light L two-dimensionally scanned by the movable device 13 is reflected by a free-form surface mirror 509, where distortion is corrected, and then focused on an intermediate screen 510 to display an intermediate image. The intermediate screen 510 is composed of a microlens array in which microlenses are arranged two-dimensionally, and the projection light L entering the intermediate screen 510 is magnified in units of microlenses.

The movable device 13 moves the reflective film portion 14 back and forth in two axial directions, two-dimensionally scanning the projection light L incident on the reflective film portion 14. The drive control of this movable device 13 is performed in synchronization with the light emission timing of the laser light sources 501R, 501G, and 501B.

The above describes the head-up display device 500 as an example of an image projection device, but the image projection device may be any device that projects an image by performing optical scanning with a movable device 13 having a reflective film portion 14. For example, the present invention can be similarly applied to a projector that is placed on a desk or the like and projects an image onto a display screen, or a head-mounted display device that is mounted on a mounting member that is attached to the observer's head or the like and projects an image onto a reflective/transmissive screen of the mounting member, or projects an image using the eyeball as a screen.

The image projection device may be mounted not only on a vehicle or a mounting member, but also on a moving body such as an aircraft, a ship, or a mobile robot, or on a non-moving body such as a work robot that operates a drive target such as a manipulator without moving from its location.

The head-up display device 500 is an example of a "head-up display" as described in the claims. The automobile 400 is an example of a "vehicle" as described in the claims.

[Fourth embodiment]
Next, an optical writing device according to a fourth embodiment will be described.

The fourth embodiment is an example of an optical writing device that uses the movable device 13 of the first embodiment described above.

Figure 16 is a schematic diagram showing an example of an image forming apparatus equipped with an optical writing device 600 according to the fourth embodiment. Also, Figure 17 is a schematic diagram showing an example of an optical writing device.

As shown in FIG. 16, the optical writing device 600 is used as a component of an image forming device such as a laser printer 650 having a printer function using laser light. In the image forming device, the optical writing device 600 optically writes on the photosensitive drum, which is the scanned surface 15, by optically scanning the photosensitive drum with one or more laser beams.

As shown in FIG. 17, in the optical writing device 600, the laser light from the light source device 12 such as a laser element passes through an imaging optical system 601 such as a collimator lens, and is then deflected in one or two axial directions by the movable device 13 having a reflective film section 14. The laser light deflected by the movable device 13 then passes through a scanning optical system 602 consisting of a first lens 602a, a second lens 602b, and a mirror section 602c, and is irradiated onto the scanned surface 15 (e.g., a photosensitive drum or photosensitive paper) to perform optical writing. The scanning optical system 602 forms a spot-shaped light beam on the scanned surface 15. In addition, the light source device 12 and the movable device 13 having the reflective film section 14 are driven under the control of the control device 11.

In this way, the optical writing device 600 can be used as a component of an image forming device having a printer function using laser light. In addition, by changing the scanning optical system to enable optical scanning not only in one axis direction but also in two axes directions, it can be used as a component of an image forming device such as a laser label device that deflects laser light onto thermal media, optically scans it, and prints by heating it.

The movable device 13 having the reflective film portion 14 applied to the optical writing device described above consumes less power to operate than a rotating polygon mirror using a polygon mirror or the like, which is advantageous for reducing the power consumption of the optical writing device. In addition, the wind noise generated when the movable device 13 vibrates is smaller than that of a rotating polygon mirror, which is advantageous for improving the quietness of the optical writing device. The optical writing device requires far less installation space than a rotating polygon mirror, and the movable device 13 generates only a small amount of heat, making it easy to miniaturize the device, which is advantageous for miniaturizing the image forming device.

[Fifth embodiment]
Next, an object recognition device according to a fifth embodiment will be described.

The fifth embodiment is an example of an object recognition device that uses the movable device 13 of the first embodiment described above.

Fig. 18 is a schematic diagram showing an example of a vehicle equipped with a LiDAR (Laser Imaging Detection and Ranging) device 700, which is an example of an object recognition device according to the fifth embodiment. Fig. 19 is a schematic diagram showing an example of the LiDAR device 700.

The object recognition device is a device that recognizes objects in the target direction, such as a lidar device 700.

As shown in FIG. 18, the lidar device 700 is mounted on, for example, a moving body such as an automobile 701, and recognizes an object 702 by optically scanning the target direction and receiving reflected light from the object 702 present in the target direction.

As shown in FIG. 19, the laser light emitted from the light source device 12 passes through an incident optical system consisting of a collimating lens 703, which is an optical system that converts divergent light into approximately parallel light, and a plane mirror 704, and is scanned in one or two axial directions by a movable device 13 having a reflective film portion 14. Then, it is irradiated onto an object 702 in front of the device through a projection lens 705, which is a projection optical system. The light source device 12 and the movable device 13 are controlled by the control device 11. The reflected light reflected by the object 702 is optically detected by a photodetector 709. That is, the reflected light passes through a condenser lens 706, which is an incident light detection and light receiving optical system, and is received by an image sensor 707, which outputs a detection signal to a signal processing circuit 708. The signal processing circuit 708 performs predetermined processing such as binarization and noise processing on the input detection signal, and outputs the result to a distance measurement circuit 710.

The distance measurement circuit 710 recognizes the presence or absence of the object 702 based on the time difference between when the light source device 12 emits the laser light and when the laser light is received by the photodetector 709, or the phase difference between each pixel of the image sensor 707 that receives the light, and further calculates the distance information to the object 702.

The movable device 13 with the reflective film portion 14 is less likely to break than a polygonal mirror and is small, making it possible to provide a small, highly durable radar device. Such a lidar device can be attached to, for example, a vehicle, an aircraft, a ship, a robot, etc., and can optically scan a specified range to determine the presence or absence of an obstacle and the distance to the obstacle.

The above object recognition device has been described as an example of a lidar device 700, but the object recognition device may be any device that performs optical scanning by controlling a movable device 13 having a reflective film portion 14 with a control device 11, and recognizes an object 702 by receiving reflected light with a photodetector, and is not limited to the above-mentioned embodiment.

For example, it can be used in biometric authentication, where object information such as shape is calculated from distance information obtained by optically scanning a hand or face, and the target object is recognized by referencing the record; security sensors recognize intruders by optically scanning a target range; and components of 3D scanners that calculate and recognize object information such as shape from distance information obtained by optical scanning, and output it as 3D data.

Sixth embodiment
Next, a laser headlamp according to a sixth embodiment will be described.

The sixth embodiment is an example of a laser headlamp in which the movable device 13 of the first embodiment described above is applied to the headlights of a moving body, such as an automobile.

Figure 20 is a schematic diagram showing an example of the configuration of a laser headlamp 50 according to the sixth embodiment.

The laser headlamp 50 has a control device 11, a light source device 12b, a movable device 13 having a reflective film portion 14, a mirror 51, and a transparent plate 52.

Light source device 12b is a light source that emits blue laser light. The light emitted from light source device 12b enters movable device 13 and is reflected by reflective film section 14. Movable device 13 moves reflective film section 14 in the XY directions based on a signal from control device 11, and performs two-dimensional scanning in the XY directions with the blue laser light from light source device 12b.

The scanning light from the movable device 13 is reflected by the mirror 51 and enters the transparent plate 52. The transparent plate 52 is coated with a yellow phosphor on either the front or back side. When the blue laser light from the mirror 51 passes through the yellow phosphor coating on the transparent plate 52, it changes to white within the legal range for headlight colors. As a result, the front of the car is illuminated with white light from the transparent plate 52.

The scanning light from the movable device 13 scatters in a certain way as it passes through the phosphor in the transparent plate 52. This reduces glare on the illuminated object in front of the vehicle.

When the movable device 13 is applied to an automobile headlight, the colors of the light source device 12b and the phosphor are not limited to blue and yellow, respectively. For example, the light source device 12b may be near-ultraviolet, and the transparent plate 52 may be covered with a uniform mixture of phosphors of the three primary colors of light: blue, green, and red. Even in this case, the light passing through the transparent plate 52 can be converted to white, and the front of the automobile can be illuminated with white light.

[Seventh embodiment]
Next, a head mounted display according to a seventh embodiment will be described.

The seventh embodiment is an example of a head-mounted display to which the movable device 13 of the first embodiment described above is applied. Here, the head-mounted display is a head-mounted display that can be worn on the human head, and can have a shape similar to glasses, for example. Hereinafter, the head-mounted display will be abbreviated to HMD.

Figure 21 is a perspective view illustrating the appearance of an HMD 60 according to the seventh embodiment. In Figure 21, the HMD 60 is composed of a front 60a and temples 60b, which are provided approximately symmetrically on the left and right. The front 60a can be composed of, for example, a light guide plate 61, and the optical system, control device, etc. can be built into the temples 60b.

Figure 22 is a diagram illustrating a partial configuration of the HMD 60. Note that while Figure 22 illustrates a configuration for the left eye, the HMD 60 has a similar configuration for the right eye.

The HMD 60 has a control device 11, a light source unit 530, a light amount adjustment unit 507, a movable device 13 having a reflective film unit 14, a light guide plate 61, and a half mirror 62.

As described above, the light source unit 530 is a unit made up of the laser light sources 501R, 501G, and 501B, the collimator lenses 502, 503, and 504, and the dichroic mirrors 505 and 506, all of which are enclosed in an optical housing. In the light source unit 530, the three color laser beams from the laser light sources 501R, 501G, and 501B are combined by the dichroic mirrors 505 and 506. The combined parallel light is emitted from the light source unit 530.

The light from the light source unit 530 is adjusted in amount by the light amount adjustment section 507 and then enters the movable device 13. The movable device 13 moves the reflective film section 14 in the XY directions based on a signal from the control device 11, and performs two-dimensional scanning of the light from the light source unit 530. The drive control of this movable device 13 is performed in synchronization with the emission timing of the laser light sources 501R, 501G, and 501B, and a color image is formed by the scanning light.

The scanning light from the movable device 13 enters the light guide plate 61. The light guide plate 61 guides the scanning light to the half mirror 62 while reflecting it on its inner wall surface. The light guide plate 61 is made of a resin or the like that is transparent to the wavelength of the scanning light.

The half mirror 62 reflects the light from the light guide plate 61 to the back side of the HMD 60 and emits it in the direction of the eyes of the wearer 63 of the HMD 60. The half mirror 62 has, for example, a free-form surface shape. An image formed by the scanning light is formed on the retina of the wearer 63 by reflection from the half mirror 62. Alternatively, an image is formed on the retina of the wearer 63 by reflection from the half mirror 62 and the lens effect of the crystalline lens in the eyeball. Furthermore, spatial distortion of the image is corrected by reflection from the half mirror 62. The wearer 63 can observe the image formed by the light scanned in the XY directions.

Since 62 is a half mirror, the image produced by the light from the outside world and the image produced by the scanning light are superimposed on each other and observed by the wearer 63. By providing a mirror instead of the half mirror 62, it is possible to eliminate the light from the outside world and to configure the wearer 63 to be able to observe only the image produced by the scanning light.

Finally, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Furthermore, each embodiment and each modification of each embodiment is included in the scope and spirit of the invention, and is included in the scope of the invention and its equivalents described in the claims.

13 Optical deflection element 14 Reflection section 50 Laser headlamp 60 Head mounted display 102 Base body 141 Protective section 142, 143 Deformable section 400, 701 Moving body 500 Image projection device, head up display 700 Object recognition device

JP 2015-102597 A

Claims (12)

A reflector;
A base supporting the reflector;
a deformation portion that is disposed in a region outside the region where the reflecting portion of the base is provided so as to surround the outer periphery of the reflecting portion, and that is formed in at least one of a protruding shape and a recessed shape from the surface where the reflecting portion is provided;
a protective portion that covers the reflective portion and the deformable portion and protects the reflective portion;
An optical deflection element comprising: The deformation portion is disposed in an annular shape so as to surround the outer periphery of the reflection portion without interruption.
2. The optical deflection element according to claim 1. The deformation portion is provided in plurality.
3. The optical deflection element according to claim 1, wherein the first and second optical elements are arranged in a first plane. The deformation portion is a groove portion recessed from a surface on which the reflection portion is provided,
The groove has a cross section having a shape in which the opening width and the bottom width are different in length.
4. The optical deflection element according to claim 1, wherein the first and second light deflectors are arranged in a first plane. The deformation portion is a groove portion recessed from a surface on which the reflection portion is provided,
The groove has a trapezoidal cross section with an opening width and a bottom width of different lengths.
4. The optical deflection element according to claim 1, wherein the first and second light deflectors are arranged in a first plane. The deformation portion is a groove portion recessed from a surface on which the reflection portion is provided,
The groove portion has a cross section obtained by cutting one end of the outer periphery of a circular shape.
4. The optical deflection element according to claim 1, wherein the first and second light deflectors are arranged in a first plane. 7. A light deflection element comprising the light deflection element according to claim 1 ,
1. An image projection device comprising: The optical deflection element according to any one of claims 1 to 6,
A head-up display that features The optical deflection element according to any one of claims 1 to 6,
A laser headlamp. The optical deflection element according to any one of claims 1 to 6,
A head mounted display characterized by: The optical deflection element according to any one of claims 1 to 6,
1. An object recognition device comprising: A head-up display comprising at least one of the head-up display according to claim 8, the laser headlamp according to claim 9, and the object recognition device according to claim 11.
A moving object characterized by:

Images