Image projection apparatus

Abstract

In the present disclosure, an image projection apparatus includes: a light source that irradiates a laser beam; a scanning device that scans the laser beam emitted from the light source; a projection optical system that emits the laser beam scanned by the scanning device and projects an image onto the retina of the user; a line-of-sight direction detector that detects a line-of-sight direction of the user on which the image is projected; and an optical system controller that controls the projection optical system on the basis of the line-of-sight direction detected by the line-of-sight direction detector, the light source includes at least one first laser element that emits laser light of a first color, at least one second laser element that emits laser light of a second color, and at least one third laser element that emits laser light of a third color.

Description

Technical Field

[0001] The present disclosure relates to an image projection device, and more particularly, to an image projection device that is miniaturized and can be driven with low power consumption. Background Art

[0002] In recent years, augmented reality (AR) glasses, as a type of wearable device of the augmented reality type using a head-mounted display method, are being developed as an image projection device.

[0003] Image projection devices such as AR glasses need to have miniaturization, low power consumption, and high resolution.

[0004] However, in order to meet the miniaturization or high-resolution requirements of various image projection devices (such as AR glasses), when reducing the size of the light source or scanning device installed on the image projection device, since the light source needs to exceed a certain light output power to meet the high-resolution requirements, it is very difficult to drive the image projection device with low power consumption. For this reason, image projection devices such as AR glasses need to have high resolution, low power consumption, and miniaturization. Summary of the Invention

[0005] The present disclosure aims to solve at least one of the above technical problems. To this end, the present disclosure provides an imaging lens, a camera module, and an imaging device.

[0006] According to the present disclosure, an image projection device includes:

[0007] A light source that irradiates a laser beam;

[0008] A scanning device configured to scan the laser beam irradiated from the light source;

[0009] A projection optical system configured to irradiate the laser beam scanned by the scanning device and project an image onto the retina of a user;

[0010] A line-of-sight direction detector configured to detect the line-of-sight direction of a user to whom the image is projected; and

[0011] An optical system controller configured to control the projection optical system based on the line-of-sight direction detected by the line-of-sight direction detector;

[0012] Wherein, the light source includes:

[0013] At least one first laser element configured to irradiate a laser of a first color,

[0014] At least one second laser element configured to irradiate a laser of a second color different from the first color, and

[0015] At least one third laser element for emitting laser light of a third color different from the first color and the second color. Description of the Drawings

[0016] These and / or other aspects and advantages of the embodiments of the present disclosure will become more apparent and easier to understand from the following description with reference to the accompanying drawings, in which:

[0017] Figure 1 is a diagram showing an exemplary configuration of an image projection device according to the present disclosure.

[0018] Figure 2 is a diagram showing the current-light output power characteristics of a first laser element according to the present disclosure.

[0019] Figure 3 is a diagram showing the current-light output power characteristics of a second laser element according to the present disclosure.

[0020] Figure 4 is a diagram showing the current-light output power characteristics of a third laser element according to the present disclosure.

[0021] Figure 5 is a diagram showing an exemplary configuration of a light source according to a first embodiment of the present disclosure.

[0022] Figure 6 is a diagram showing another exemplary configuration of a light source according to a first embodiment of the present disclosure.

[0023] Figure 7 is a diagram showing a scanning method of a scanning device according to the present disclosure.

[0024] Figure 8 is a diagram showing the spatial resolution of a scanning device according to the present disclosure.

[0025] Figure 9 is a diagram showing an exemplary configuration of a tilt mirror module according to the present disclosure.

[0026] Figure 10 is a diagram showing an exemplary control of a tilt mirror module by an optical system controller according to the present disclosure.

[0027] Figure 11 is a diagram showing an exemplary control of a tilt mirror module by an optical system controller according to the present disclosure.

[0028] Figure 12 is a diagram showing an exemplary control of each laser element by a light source controller according to the present disclosure.

[0029] Figure 13This is a diagram showing an exemplary configuration of a light source according to a second embodiment of the present disclosure.

[0030] Figure 14 This is a diagram depicting the configuration of a plurality of first laser elements according to a second embodiment of the present disclosure.

[0031] Figure 15 This is a diagram depicting the configuration of a plurality of second laser elements according to a second embodiment of the present disclosure.

[0032] Figure 16 This is a diagram depicting the configuration of a plurality of third laser elements according to a second embodiment of the present disclosure.

[0033] Figure 17 This is a diagram showing the relationship between the scanning conditions and the resolution of a scanning device according to a second embodiment of the present disclosure.

[0034] Figure 18 This is a diagram showing the spatial resolution of a scanning device according to a second embodiment of the present disclosure.

[0035] Figure 19 This is a diagram showing an exemplary control of each laser element by a light source controller according to a second embodiment of the present disclosure.

[0036] Figure 20 This is a diagram depicting the emitter size of a plurality of laser elements according to a second variant embodiment of a second embodiment of the present disclosure.

[0037] Figure 21 This is a schematic diagram showing the relationship between the spacing of a plurality of laser elements and the emitter size corresponding to the number of beams according to a second variant embodiment of a second embodiment of the present disclosure.

[0038] Figure 22 This is a diagram showing an exemplary configuration of a light source according to a third variant embodiment of a second embodiment of the present disclosure.

[0039] Figure 23 This is a diagram showing a beam deflector according to a third variant embodiment of a second embodiment of the present disclosure.

[0040] Figure 24 This is a diagram showing another exemplary configuration of a light source according to a third variant embodiment of a second embodiment of the present disclosure.

[0041] Figure 25 This is a diagram showing an exemplary configuration of a light source according to a fourth variant embodiment of a second embodiment of the present disclosure.

[0042] Figure 26FIG. 0 is a diagram showing an exemplary control of each laser element by a light source controller according to a fourth variant embodiment of the second embodiment of the present disclosure.

[0043] Figure 27 FIG. 4 is a diagram showing an exemplary irradiation of a laser beam of a light source according to a fourth variant embodiment of the second embodiment of the present disclosure.

[0044] Figure 28 FIG. 8 is a diagram showing another exemplary configuration of a light source according to a fourth variant embodiment of the second embodiment of the present disclosure.

[0045] Figure 29 FIG. 12 is a diagram showing an exemplary configuration of a light source according to a first variant embodiment of the first and second embodiments of the present disclosure.

[0046] Figure 30 FIG. 16 is a diagram showing an exemplary configuration of a light source according to a second variant embodiment of the first and second embodiments of the present disclosure.

[0047] Figure 31 FIG. 20 is a diagram showing an exemplary configuration of a light source according to a third variant embodiment of the first and second embodiments of the present disclosure.

[0048] Figure 32 FIG. 24 is a diagram showing an exemplary configuration of a light source according to a fourth variant embodiment of the first and second embodiments of the present disclosure.

[0049] Figure 33 FIG. 28 is a diagram showing an exemplary configuration of a light source according to the third embodiment of the present disclosure.

[0050] Figure 34 FIG. 32 is a diagram showing an exemplary configuration of a light source according to the fourth embodiment of the present disclosure.

[0051] Figure 35 FIG. 36 is a diagram showing another exemplary configuration of a light source according to the fourth embodiment of the present disclosure.

[0052] Figure 36 FIG. 40 is a diagram showing an exemplary control of each laser element by a light source controller according to the fourth embodiment of the present disclosure.

[0053] Figure 37 FIG. 44 is a diagram showing an exemplary configuration of a waveguide type optical multiplexer according to a third variant embodiment of the third and fourth embodiments of the present disclosure. DETAILED DESCRIPTION

[0054] Embodiments of the present disclosure will be described in detail, and examples of the embodiments are shown in the accompanying drawings. Throughout the description, the same or similar elements and elements having the same or similar functions are denoted by the same reference numerals. The embodiments described herein with reference to the drawings are illustrative and are intended to explain the present disclosure, but should not be construed as limiting the present disclosure.

[0055] First Embodiment

[0056] An image projection device according to the present disclosure will be described below. The image projection device according to the present disclosure is an eye-tracking retinal projection type head-mounted display that tracks the user's line-of-sight direction and projects an image onto the user's retina. As Figure 1 shown, the image projection device 1 according to the present disclosure includes a light source 11, a collimating optical system 12, a beam shaping unit 13, a scanning device 14, a projection optical system 15, a line-of-sight direction detector 16, an optical system controller 17, a light source controller 18, and an angular velocity sensor 19.

[0057] The light source 11 emits a laser beam toward the scanning device 14. Specifically, as Figure 1 shown, the scanning device 11 includes at least one first laser element 111 that emits red light (i.e., the first color), at least one second laser element 112 that emits green light (i.e., the second color), and at least one third laser element 113 that emits blue light (i.e., the third color). In the present embodiment, the light source 11 includes one first laser element 111, one second laser element 112, and one third laser element 113. The light source 111 multiplexes the RGB laser beams emitted from each of the first laser element 111, the second laser element 112, and the third laser element 113 and irradiates them onto the scanning device 14. The wavelength of the first laser element may be 650 nm, the wavelength of the second laser element may be 520 nm, and the wavelength of the third laser element may be 450 nm. The image projection device 1 can expand the color range by configuring the wavelengths of the first laser element 111, the second laser element 112, and the third laser element 113 to the above values. Similarly, since the retinal projection method, that is, the image projection device according to the present disclosure, does not require light output power, the optimal wavelength can be easily selected as described above to expand the color range.

[0058] In addition, in the light source 11 according to the present embodiment, each of the first laser element 111, the second laser element 112, and the third laser element 113 can be a Vertical Cavity Surface Emitting Laser (VCSEL) element. The first laser element 111, which is a VCSEL element, has a first active layer that generates light. The first active layer includes Aluminum Gallium Indium Phosphide (AlGaInP). The second laser element 112, which is a VCSEL element, has a second active layer that generates light. The second active layer includes Indium Gallium Nitride (InGaN). In addition, the third laser element 113, which is a VCSEL element, has a third active layer that generates light. The third active layer includes InGaN, which is equivalent to the second active layer. VCSEL elements, especially those with a high-reflectivity Distributed Bragg Reflector (DBR) structure, effectively expand the color range to a great extent because the desired wavelength can be selected and the wavelength does not change.

[0059] Examples of the specific structures of the first laser element 111, the second laser element 112, and the third laser element 113 according to the present embodiment are referred to the following non-patent documents: Non-patent Document 1 [Kenichi Terao et al (2021). PROCEEDINGS OF THE INTERNATIONAL DISPLAY WORKSHOPS, VOL. 28] and Non-patent Document 2 [Tatsushi Hamaguchi et al (2018). Lateral optical confinement of GaN-based VCSEL using an atomically smooth monolithic curved mirror. Scientific Reports]. The first laser element 111, the second laser element 112, and the third laser element 113 according to the present disclosure can have various structures.

[0060] As Figures 2 to 4 shown, the light output power of each of the first laser element 111, the second laser element 112, and the third laser element 113 in the present embodiment is less than or equal to 1 mW. Since the image projection device 1 according to the present disclosure is a retinal projection type display that projects an image directly onto the user's retina, the light output power of each of the first laser element 111, the second laser element 112, and the third laser element 113 can be reduced.

[0061] Similarly, as Figures 2 to 4 shown, by changing the material composition of the high-reflection DBR structure or increasing the reflectivity of the high-reflection DBR structure, and by changing the mirror shape of the high-reflection DBR structure, etc., the threshold current - that is, the minimum current required for each of the first laser element 111, the second laser element 112, and the third laser element 113 to emit each laser beam - is preferably less than or equal to 6 mA, more preferably less than or equal to 3 mA, and even further preferably less than or equal to 1 mA. Thus, since the image projection device 1 according to the present disclosure is a retinal projection type display that directly projects an image onto the user's retina, the light output power of each of the first laser element 111, the second laser element 112, and the third laser element 113 can be reduced, and thus the threshold current, that is, the minimum current required to emit the laser beam, can be reduced.

[0062] Next, the detailed configuration of the light source 11 will be described. As Figure 5 shown, the light source 11 of the present embodiment includes a first laser element 111, a second laser element 112, and a third laser element 113, a first semiconductor chip 114, a second semiconductor chip 115, a third semiconductor chip 116, a drive circuit 117, a first collimating lens 118, a second collimating lens 119, a third collimating lens 120, and a multiplexing optical system 121. Each of the first laser element 111, the second laser element 112, and the third laser element 113 may include a semiconductor substrate. In this case, in one example, the semiconductor substrate is preferably disposed between a first high-reflection DBR and a second high-reflection DBR sandwiching an active layer. The semiconductor substrate is not limited to this structure and may also be disposed outside either the first high-reflection DBR or the second high-reflection DBR.

[0063] The first semiconductor chip 114 includes the first laser element 111. In the present embodiment, as Figure 5 shown, the first semiconductor chip 114 is disposed on the drive circuit 117.

[0064] The second semiconductor chip 115 includes the second laser element 112. In the present embodiment, as Figure 5 shown, the second semiconductor chip 115 is disposed on the drive circuit 117.

[0065] The third semiconductor chip 116 includes the third laser element 113. In the present embodiment, as Figure 5 shown, the third semiconductor chip 116 is disposed on the drive circuit 117.

[0066] As described above, by arranging each semiconductor chip including each laser element on the drive circuit 117, the wiring connecting each semiconductor chip and the drive circuit 117 can be shortened. Therefore, high-frequency characteristics and high gradation characteristics can be achieved.

[0067] The drive circuit 117 is a circuit that drives each of the first laser element 111, the second laser element 112, and the third laser element 113. As Figure 5 shown, the drive circuit 117 is arranged on the opposite side of the emission direction of each of the first laser element 111, the second laser element 112, and the third laser element 113. It should be noted that although one drive circuit 117 is provided for the first laser element 111, the second laser element 112, and the third laser element 113, drive circuits 117 can also be provided separately for the first laser element 111, the second laser element 112, and the third laser element 113.

[0068] The first collimating lens 118 is arranged between the first laser element 111 and the multiplexing optical system 121 to collimate the laser beam emitted from the first laser element 111.

[0069] The second collimating lens 119 is arranged between the second laser element 112 and the multiplexing optical system 121 to collimate the laser beam emitted from the second laser element 112.

[0070] The third collimating lens 120 is arranged between the third laser element 113 and the multiplexing optical system 121 to collimate the laser beam emitted from the third laser element 113.

[0071] The first collimating lens 118, the second collimating lens 119, and the third collimating lens 120 collimate the laser beams emitted from the first laser element 111, the second laser element 112, and the third laser element 113 respectively, so that the laser beams emitted from the first laser element 111, the second laser element 112, and the third laser element 113 have the same beam diameter.

[0072] In the present embodiment, as Figure 6 shown, the first collimating lens 118, the second collimating lens 119, and the third collimating lens 120 can be diffractive lenses instead of Figure 5 the conventional bulk lenses shown, thereby reducing the thickness.

[0073] Diffractive lenses are also called meta-lenses. If the first collimating lens 118, the second collimating lens 119, and the third collimating lens 120 are meta-lenses, then as Figure 6As shown, the metasurface lens is arranged to be in contact with the respective exit surfaces of the first collimating lens 118, the second collimating lens 119, and the third collimating lens 120. In this way, by using the metasurface lens for the first collimating lens 118, the second collimating lens 119, and the third collimating lens 120, since the metasurface lens contacts the exit surface of each collimating lens, the thinning and miniaturization of the first collimating lens 118, the second collimating lens 119, and the third collimating lens 120 can be achieved, and the beam diameter of the laser beam emitted from each laser element can be made smaller. In addition, in the present embodiment, since each laser element is a VCSEL element with a very small wavelength change, the metasurface lens can be used as an effective collimating lens to achieve thinning and miniaturization.

[0074] The multiplexing optical system 121 multiplexes the laser beams emitted from each of the first laser element 111, the second laser element 112, and the third laser element 113 to emit a multiplexed beam. In the present embodiment, as Figure 5 shown, the multiplexing optical system 121 includes a first reflection optical system 1211, a second reflection optical system 1212, and a third reflection optical system 1213.

[0075] The first reflection optical system 1211 is arranged to reflect the laser beam emitted from the first laser element 111 toward the scanning device 14 side; the second reflection optical system 1212 is arranged to reflect the laser beam emitted from the second laser element 112 toward the scanning device 14 side; the third reflection optical system 1213 is arranged to reflect the laser beam emitted from the third laser element 113 toward the scanning device 14 side. The first reflection optical system 1211, the second reflection optical system 1212, and the third reflection optical system 1213 are also arranged such that the laser beams reflected from each of the first reflection optical system 1211, the second reflection optical system 1212, and the third reflection optical system 1213 are multiplexed on the same optical axis.

[0076] In the present embodiment, the first reflection optical system 1211, the second reflection optical system 1212, and the third reflection optical system 1213 can be optical systems having a dichroic function. In this case, it is necessary to match the polarization directions of the light beams of each wavelength. Similarly, the light beams of each wavelength can be adjusted by using a λ / 2 plate or a λ / 4 plate (not shown) to change the direction of linearly polarized light and change the linearly polarized light into circularly polarized light.

[0077] The collimating optical system 12 collimates the laser beam emitted from the light source 11 and emits the collimated laser beam toward the scanning device 14 side. As Figure 1 shown, the collimating optical system 12 is arranged between the light source 11 and the scanning device 14. Although in Figure 1In the illustrated embodiment, the collimating optical system 12 has one lens, but the configuration of the collimating optical system 12 is not limited thereto. That is to say, the configuration of the collimating optical system 12 is arbitrary, and it may include multiple lenses, or may include a single lens such as a self-focusing (SELFOC) lens, etc.

[0078] The beam shaping unit 13 shapes the laser beam emitted from the light source 13. The beam shaping unit 13 may be configured as a mask, an optical filter (such as a neutral density (ND) filter, a Gaussian beam filter, or a rectangular beam filter), or a combination thereof. As Figure 1 shown, the beam shaping unit 13 is disposed between the collimating optical system 12 and the scanning device 14. In Figure 1 the illustrated embodiment, the beam shaping unit 13 is configured as a mask having holes. It should be noted that if the beam shaping unit 13 is configured as an optical ND filter, the optical ND filter can not only remove natural light (for example, light emitting diode (LED) light), but also avoid the kink effect that may occur when the first laser element, the second laser element, and the third laser element are driven with a relatively high current, so as to avoid driving with a micro output current very close to the threshold current and project a high-resolution image onto the user's retina. The Gaussian beam filter can reduce the sidelobes of the beam that finally converges on the user's retina and generate a high-resolution image. On the other hand, the rectangular beam filter can reduce the beam diameter and improve the resolution by generating sidelobes. In this way, the image projection device 1 according to the present disclosure includes a beam shaping unit 13 that shapes the required beam.

[0079] The scanning device 14 disposed between the beam shaping unit 13 and the projection optical system 15 performs two-dimensional scanning on the laser beam emitted from the light source 11. The scanning device 14 may be a scanning mirror, such as a micro electro mechanical system (MEMS) mirror. The scanning device 14 can perform main scanning in a resonant operation and perform secondary scanning in a non-resonant operation to perform scanning. In the present embodiment, the scanning device 14 adopts a luster scanning method and performs scanning by using the resonance of the laser beam emitted from the light source 11 in the main scanning direction as Figure 7 shown. By performing scanning with the scanning device adopting the luster scanning method, a high-quality image can be projected onto the user's retina.

[0080] The relationship between the scanning device 14 and the resolution of the image can be expressed by the following formula.

[0081] N = (θ op t * D) / (1.1 * λ) (1)

[0082] In Equation (1), θ opt is the optical swing angle for two-dimensionally scanning the laser beam emitted from the light source 11 (the same hereinafter). D is the diameter of the scanning device 14 (the same hereinafter). λ is the wavelength of the laser beam (the same hereinafter). Therefore, in order to project a higher-resolution image onto the user's retina, θ opt *D should be increased.

[0083] As Figure 8 shown, when projecting an image onto the user's retina at a frame rate of 60 Hz and a resolution of 4K, the scanning device 14 requires a resonance frequency of 72 kHz, and θ opt *D is 168 [deg·mm].

[0084] The projection optical system 15 is an optical system that projects an image by irradiating the laser beam scanned by the scanning device 14 onto the user's retina. As Figure 1 shown, the projection optical system 15 of the present embodiment includes a first lens 151, a second lens 152, a first mirror 153, a tilt mirror module 154 having a tilt mirror as the second mirror, and a third mirror 155.

[0085] The first lens 151 and the second lens 152 are disposed between the scanning device 14 and the first mirror 153, and are configured to convert the laser beam scanned by the scanning device 14 into a parallel beam and emit it toward the first mirror 153. Although the projection optical system 15 in the present embodiment converts the laser beam scanned by the scanning device 14 into a parallel beam through the first lens 151 and the second lens 152, the projection optical system may also convert the laser beam into a parallel beam through three or more lenses.

[0086] The first mirror 153 is disposed between the second lens 152 and the tilt mirror module 154, and is configured to reflect the laser beam emitted from the second lens 152 to the tilt mirror module 154. Similarly, the first mirror 153 according to the present embodiment allows the laser beam reflected by the tilt mirror module 154 to pass through. That is, Figure 1 the first mirror 153 in the shown embodiment may be a semi-reflective mirror.

[0087] The tilt mirror module 154 disposed between the first mirror 153 and the third mirror reflects the laser beam reflected by the first mirror 153 to the third mirror 155. The optical system controller 17 controls the tilt mirror module 154 based on the user's line-of-sight direction detected by the line-of-sight direction detector 16 and / or the angular velocity of the image projection device 1 detected by the angular velocity sensor 19, so that the laser beam reflected by the tilt mirror module 154 is projected onto the user's retina. As Figure 9As shown, the tilt mirror module 154 includes a movable body 1541, a gimbal mechanism 1542, a magnetic drive mechanism 1543, a fixed body 1544, a Hall sensor 1545, and a tilt mirror module drive mechanism 1546.

[0088] The movable body 1541 includes a tilt mirror 1541a, which is a second mirror that reflects the laser beam reflected by the first mirror 153 to the third mirror 155. The movable body 1541 is supported relative to the fixed body 1544 by the gimbal mechanism 1542 such that the tilt mirror 1541a vibrates about the rotation center (RC).

[0089] For example, the gimbal mechanism 1542 is configured as a metal reed. The gimbal mechanism 1542 supports the movable body 1541 relative to the fixed body 1544 such that the tilt mirror 1541a vibrates about the rotation center (RC). In Figure 9 the illustrated embodiment, the gimbal mechanism 1542 supports the movable body 1541 such that the tilt mirror 1541a vibrates in the X-axis and Y-axis directions relative to the fixed body 1544 about the rotation center (RC).

[0090] The magnetic drive mechanism 1543 generates a magnetic driving force between the movable body 1541 and the fixed body 1544, causing the movable body 1541 to be displaced relative to the fixed body 1544. The magnetic drive mechanism 1543 may include a coil 1543a and a magnet 1543b as Figure 8 shown. In Figure 8 the illustrated embodiment, the coil 1543a is provided on the movable body 1541, the magnet 1543b is provided on the fixed body 1544, and the coil 1543a and the magnet 1543b are disposed opposite to each other.

[0091] The fixed body 1544 is provided in a manner that its angles about the X-axis and Y-axis are variable. By changing the angles of the fixed body 1544 about the X-axis and Y-axis, the tilt mirror included in the movable body 1541 can project a laser beam based on the user's line of sight direction and project an image onto the user's retina.

[0092] The Hall sensor 1545 detects the tilt of the movable body 1541. The Hall sensor 1545 is provided near the magnet 1543b and above the movable body 1541. In Figure 9 the illustrated embodiment, the Hall sensor 1545 is provided inside the coil 1543a. By outputting the tilt angle of the movable body 1541 detected by the Hall sensor 1545 to the optical system controller 17, the angle of the mirror reflecting surface of the tilt mirror 1541a can be controlled with high precision and responsiveness having sufficient frequency characteristics.

[0093] The tilt mirror module drive mechanism 1546 is a drive mechanism that changes the angle of the tilt mirror 1541a based on the line-of-sight direction detected by the line-of-sight direction detector 16. For example, the tilt mirror module drive mechanism 1546 can be configured with a drive source such as the magnetic circuit, piezoelectric element, or motor described above. Specifically, the tilt mirror module drive mechanism 1546 matches the eye movement tracking retinal projection method because the tilt mirror method with a magnetic circuit configuration using the gimbal method can obtain excellent frequency characteristics and can be miniaturized.

[0094] The third mirror 155 is arranged between the tilt mirror module 154 and the user's retina, and reflects the laser beam reflected by the tilt mirror module 154 to the user's retina. The third mirror can be a holographic optical system or a free-form mirror, etc.

[0095] The line-of-sight direction detector 16 includes an illuminator 16-1 and a line-of-sight position detector 16-2. Among them, the illuminator 16-1 irradiates a light beam onto the user's eyes, and the line-of-sight position detector 16-2 detects the line-of-sight direction of the user of the projected image. The illuminator 16-1 refers to a low-power laser element such as a VCSEL or an LED. The line-of-sight position detector 16-2 is a detection sensor that detects the line-of-sight position of the user. The line-of-sight direction detector 16 outputs the detected line-of-sight direction-related information to the optical system controller 17 or the light source controller 18. The line-of-sight direction detector 16 can be an eye movement tracking camera, etc.

[0096] The optical system controller 17 controls the projection optical system 15 based on the line-of-sight direction detected by the line-of-sight direction detector 16. Specifically, as Figure 10 and Figure 11 shown, based on the line-of-sight direction detected by the line-of-sight direction detector 16, the optical system controller 17 controls the tilt mirror module drive mechanism 1546 of the tilt mirror module 154, irradiates a laser beam, and projects an image onto the user's retina.

[0097] Similarly, the optical system controller 17 can control the magnetic drive mechanism 1543 of the tilt mirror module 154 based on the detection results of the angular velocity sensor 19 and the line-of-sight direction detector 16. If the angular velocity sensor 19 detects the angular velocity of the image projection device 1, the optical system controller 17 supplies a drive current to the coil 1543a based on the detection result of the angular velocity sensor 19 to cancel the tilt through the micro-vibration on the tilt mirror 1541a. In this way, even if the tilt mirror is affected by vibration, since the tilt mirror 1541a can vibrate around the rotation center RC, the image can also be projected onto the retina according to the user's line-of-sight direction. Therefore, by controlling the tilt mirror 1541a based on the detection result of the line-of-sight direction detector 16, the eye box can be broadened.

[0098] The light source controller 18 controls the light source 11 to control the laser beam emitted from the light source 11. Specifically, when input image data is received, the light source controller 18 controls each of at least one first laser element 111, at least one second laser element 112, and at least one third laser element 113 such that an image based on the input image data is projected onto the user's retina. More specifically, the light source controller 18 controls the modulation frequency of each of at least one first laser element 111, at least one second laser element 112, and at least one third laser element 113 such that an image based on the input image data is projected onto the user's retina. More specifically, as Figure 12 shown, the light source controller 18 outputs an input signal based on the input image data to the light source 11. Then, based on the input signal, the light source 11 inputs a current for driving each laser element to each laser element, performs linear modulation, emits each laser beam, changes the gray scale, and displays an image.

[0099] Similarly, the light source controller 18 controls the resolution of the image projected onto the user's retina based on the line-of-sight direction detected by the line-of-sight direction detector 16. Specifically, the light source controller 18 can change the resolution by changing the modulation frequency. More specifically, the light source controller 18 can control the light source 11 such that the image resolution outside a predetermined area of the image projected in the user's line-of-sight direction is lower than the image resolution within the predetermined area. More specifically, the light source controller 18 can control the signal input to the light source 11 such that, based on the line-of-sight direction detected by the line-of-sight direction detector 16, the image resolution in the area outside the line-of-sight direction is lower than the image resolution in the line-of-sight direction area, and control the modulation frequency of the light source 11. In this way, the image projection device 1 only improves the resolution of the image projected onto the area in the user's line-of-sight direction, such that the image resolution outside the predetermined area of the image projected in the user's line-of-sight direction is lower than the image resolution within the predetermined area, thereby reducing the load of image data processing and power consumption.

[0100] Similarly, the light source controller 18 can be controlled such that, based on the detection result of a photodetector that detects the radiation intensity of the laser beam emitted from the light source 11, the output of each of the first laser element 111, the second laser element 112, and the third laser element 113 is finely adjusted, and the gray scale of the linear modulation is changed to a corrected gray scale. Specifically, by generating a correction current for driving the first laser element 111, the second laser element 112, and the third laser element 113 based on the detection result of the photodetector, the light source controller 18 corrects the gray scale of the linear modulation of each of the first laser element 111, the second laser element 112, and the third laser element 113.

[0101] In addition, based on the detection results of temperature sensors that measure the temperatures of each of the first laser element 111, the second laser element 112, and the third laser element 113, the light source controller 18 can correct the gray levels of the linear modulation of each of the first laser element 111, the second laser element 112, and the third laser element 113. Specifically, by generating correction currents for driving the first laser element 111, the second laser element 112, and the third laser element 113 based on the detection results of the temperature sensors, the light source controller 18 controls the gray levels of the linear modulation of each of the first laser element 111, the second laser element 112, and the third laser element 113 to be corrected.

[0102] It should be noted that the method of reducing the image resolution outside a predetermined area of the image projected in the user's line-of-sight direction to be lower than the image resolution within the predetermined area is not limited to being achieved by controlling the modulation frequency of each light source. The image projection device 1 may include an image processing device (not shown). The image processing device performs image processing based on the line-of-sight direction detected by the line-of-sight direction detector 16 such that the resolution of the image data outside the area corresponding to the line-of-sight direction is lower than the resolution of the image data within the area corresponding to the line-of-sight direction. Then, by inputting the image data after image processing into the light source controller 18, the light source controller 18 can control the light source 11 such that the image resolution outside the predetermined area of the image projected in the user's line-of-sight direction is higher than or lower than the image resolution within the predetermined area.

[0103] As described above, the image projection device 1 according to the present embodiment can suppress the output of the laser beam because the image projection device 1 is an eye-tracking retinal projection type device that detects the user's line-of-sight direction and projects an image onto the user's retina according to the detected line-of-sight direction. This device can achieve stable operation while being driven with low power consumption without the threshold current value being changed due to self-heating because the image projection device 1 can operate with a low threshold current. In addition, the load of image processing can be reduced by reducing the nearby resolution, which can also reduce the power consumption of image processing.

[0104] Similarly, in the above-described first embodiment, since the first laser element 111, the second laser element 112, and the third laser element 113 are VCSEL elements, the wavelength hardly changes even when the drive current value is changed, so high color reproducibility can be achieved.

[0105] Similarly, in the above-described first embodiment, since the drive circuit 117 is provided on the opposite side of the emission direction of each of the first laser element 111, the second laser element 112, and the third laser element 113, the capacitance can be small, the linear modulation of the first laser element 111, the second laser element 112, and the third laser element 113 is fast, the output stability of each laser element is achieved at low gray levels, and high brightness of the image projected onto the user's retina is achieved at high gray levels, having a high speed rate for achieving not only 10-bit gray levels but also 16-bit gray levels. In addition, by reducing the adjacent resolution, the power consumption can be reduced, which enables the image projection device 1 to still maintain low power consumption even when 16-bit gray levels are achieved.

[0106] It should be noted that, in the above-described first embodiment, each of the first laser element 111, the second laser element 112, and the third laser element 113 is configured as a VCSEL element, but each of the first laser element 111, the second laser element 112, and the third laser element 113 can be configured as an edge-emitting laser element. Even when each of the first laser element 111, the second laser element 112, and the third laser element 113 is configured as an edge-emitting laser element, the output of the laser beam can be suppressed because the image projection device 1 is an eye-tracking retina projection type device that detects the user's line-of-sight direction and projects an image onto the user's retina according to the detected line-of-sight direction, and the device can achieve stable operation while being driven at low power consumption without the threshold current value being changed due to self-heating, because the image projection device 1 can operate at a low threshold current.

[0107] Second Embodiment

[0108] In the above-described first embodiment, the light source 11 of the image projection device 1 is configured as one first laser element 111, one second laser element 112, and one third laser element 113, but the number of each laser element is not limited to one. In the second embodiment, the light source 11 of the image projection device 1 may include a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113. The following will describe the parts different from the above-described first embodiment.

[0109] As Figure 13As shown, the light source 11 of the present embodiment includes a plurality of first laser elements 111, a plurality of second laser elements 112, a plurality of third laser elements 113, a first semiconductor chip 114, a second semiconductor chip 115, a third semiconductor chip 116, a drive circuit 117, a first collimating lens 118, a second collimating lens 119, a third collimating lens 120, and a multiplexing optical system 121. Note that the configuration of the multiplexing optical system 121 is the same as that of the first embodiment described above, and thus will not be described in detail. Each of the first laser element 111, the second laser element 112, and the third laser element 113 may include a semiconductor substrate. In this case, in one example, it is preferable to dispose the semiconductor substrate between a first highly reflective DBR and a second highly reflective DBR sandwiching the active layer. The semiconductor substrate is not limited to this structure and may also be disposed outside either the first highly reflective DBR or the second highly reflective DBR.

[0110] As Figure 13 and Figure 14 shown, the plurality of first laser elements 111 include first laser elements 111a - 111d having an active layer of AlGaInP as a red first laser element group. The plurality of first laser elements 111 are integrated on the same first semiconductor substrate 1111. Similarly, as Figure 13 and Figure 14As shown, a plurality of first laser elements 111 are arranged in one direction on a first semiconductor substrate 1111, separated from each other by a predetermined interval. Since the emitter size ES1 is large, the diameter D of the MEMS should also be large, where the emitter size ES1 is the distance between the centers of the light-emitting portions of the first laser elements 111d and 111a, which are the farthest apart among the first laser elements 111a - 111d. Therefore, this can increase the resonance frequency and reduce the resolution. On the other hand, if the emitter size ES1 is small, the optical output power of the laser elements becomes unstable due to the influence of heat generated by adjacent elements, and it is difficult to manufacture the first laser element group. In particular, using laser elements with a small oscillation threshold can reduce the thermal interference between them because, compared with ordinary laser diodes (LDs), the VCSEL method can easily achieve an oscillation threshold less than or equal to 1 mA, and the retinal projection method does not require optical output power. Therefore, this can reduce the emitter size, and the emitter size ES1 according to the present embodiment, for example, avoids thermal interference between adjacent light beams, provides a beam expander in the optical system of the light source 11, and the emitter size ES1 is less than or equal to 90 μm to implement a small optical system for the light source 11. Preferably, the emitter size ES1 is less than or equal to 30 μm to miniaturize the optical system of the light source 11, and more preferably less than or equal to 5 μm, thereby greatly improving the resolution, such as up to 4K, and achieving the ultimate miniaturization of the optical system of the light source 11 (the same hereinafter).

[0111] As Figure 13 and Figure 15 shown, a plurality of second laser elements 112 include second laser elements 112a - 112d with an active layer of InGaN as a green second laser element group. The plurality of second laser elements 112 are integrated on the same second semiconductor substrate 1121. Similarly, as Figure 13 and Figure 15 shown, a plurality of second laser elements 112 are arranged in one direction on the second semiconductor substrate 1121, separated from each other by a predetermined interval. The emitter size ES2, that is, the distance between the centers of the light-emitting portions of the second laser elements 112a and 112d, which are the farthest apart among the second laser elements 112a - 112d, can be less than or equal to 90 μm, preferably less than or equal to 30 μm, and more preferably less than or equal to 5 μm.

[0112] As Figure 13 and Figure 16 shown, a plurality of third laser elements 113 include third laser elements 113a - 113d with an active layer of InGaN as a blue third laser element group. The plurality of third laser elements 113 are integrated on the same third semiconductor substrate 1131. Similarly, as Figure 13 andFigure 16 As shown, a plurality of third laser elements 113 are arranged in one direction on a third semiconductor substrate 1131, separated from each other by a predetermined interval. The emitter size ES3, that is, the distance between the centers of the light-emitting portions of the third laser elements 113a - 113d that are the farthest apart among the third laser elements 113a - 113d, can be less than or equal to 90 μm, preferably less than or equal to 30 μm, and more preferably less than or equal to 5 μm.

[0113] A plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113 are arranged such that the emitter sizes ES1 - ES3 are the same.

[0114] It should be noted that Figure 13 The illustrated embodiment includes four first laser elements 111, four second laser elements 112, and four third laser elements 113, but the number of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is arbitrary and can be less than or equal to 3, or less than or equal to 6.

[0115] The first semiconductor chip 114 includes a plurality of first laser elements 111. In this embodiment, as Figure 13 shown, the first semiconductor chip 114 is arranged on the drive circuit 117.

[0116] The second semiconductor chip 115 includes a plurality of second laser elements 112. In this embodiment, as Figure 13 shown, the second semiconductor chip 115 is arranged on the drive circuit 117.

[0117] The third semiconductor chip 116 includes a plurality of third laser elements 113. In this embodiment, as Figure 13 shown, the third semiconductor chip 116 is arranged on the drive circuit 117.

[0118] The drive circuit 117 is a circuit that drives each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113. As Figure 13 shown, the drive circuit 117 is arranged on the opposite side of the emission direction of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113.

[0119] The first collimating lens 118 is arranged between the plurality of first laser elements 111 and the multiplexing optical system 121 to collimate the plurality of laser beams emitted from the plurality of first laser elements 111. That is, as Figure 13 shown, the light source 11 according to this element includes one first collimating lens 118 for the plurality of first laser elements 111.

[0120] A second collimating lens 119 is arranged between the plurality of second laser elements 112 and the multiplexing optical system 121 to collimate the plurality of laser beams emitted from the plurality of second laser elements 112. That is, as Figure 13 shown, the light source 11 of this element includes one second collimating lens 119 for the plurality of second laser elements 112.

[0121] A third collimating lens 120 is arranged between the plurality of third laser elements 113 and the multiplexing optical system 121 to collimate the plurality of laser beams emitted from the plurality of third laser elements 113. That is, as Figure 13 shown, the light source 11 of this element includes one third collimating lens 120 for the plurality of third laser elements 113.

[0122] It should be noted that, in this embodiment, one first collimating lens 118 is provided for the plurality of first laser elements 111, one second collimating lens 119 is provided for the plurality of second laser elements 112, and one third collimating lens 120 is provided for the plurality of third laser elements 113, but the embodiment is not limited thereto. It should be noted that one first collimating lens 118, one second collimating lens 119, and one third collimating lens 120 can be provided for each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113.

[0123] By reducing the resonance frequency according to the respective numbers of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the optical swing angle θ opt is increased, and θ in formula (1) opt *D is increased. The scanning device 14 according to this embodiment scans the laser beam in this way. Therefore, this can improve the resolution of the image projected onto the user's retina. Specifically, as Figure 8 and Figure 17 shown, compared with scanning the laser beams emitted from one first laser element 111, one second laser element 112, and one third laser element 113, when the scanning device 14 scans the laser beams emitted from each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the resonance frequency of the MEMS can be reduced, θ in formula (1) opt *D is increased, and the resolution of the image projected onto the user's retina can be improved. That is, when scanning the laser beams emitted from each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, and when the resolution of the image projected onto the user's retina is the same, as Figure 18As shown, the scanning device 14 can reduce the resonance frequency in the main scanning direction according to the number of a plurality of laser elements, and increase θ in Equation (1) opt *D to improve the resolution and reduce the modulation frequency of the laser elements. Similarly, since the light source 11 of the present embodiment can scan a laser beam by using a gloss scanning method with a light source in which a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113 are each separated by a predetermined interval, to reduce the resonance frequency in the main scanning direction and increase the optical swing angle θ opt , correspondingly increasing θ in Equation (1) opt *D, therefore, an image is projected onto the user's retina at a resolution higher than High Definition (HD), for example, HD, FHD, 2K, and 4K resolutions.

[0124] According to the respective numbers of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the light source controller 18 of the present embodiment controls the light source 11 such that the modulation frequency of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is lower than the modulation frequency of each laser element when one first laser element 111, one second laser element 112, and one third laser element 113 are provided. In the case of equivalent resolution, for example, when using one first laser element 111, one second laser element 112, and one third laser element 113 to project an image at FHD resolution and 120Hz frame rate, it is necessary to control each of the first laser element 111, the second laser element 112, and the third laser element 113 at a modulation frequency of 1920*1080*120 = 250MHz; however, when using four first laser elements 111, four second laser elements 112, and four third laser elements 113 to project an image at FHD resolution and 120Hz frame rate, 250MHz / 4 = 62.5MHz is sufficient to control the four first laser elements 111, the four second laser elements 112, and the four third laser elements 113. That is, as Figure 19 shown, in the case of equivalent resolution, based on the image data output to each laser element including the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the light source controller 18 makes the modulation frequency of each input signal lower than Figure 12 the frequency in. In this way, high gray levels can be achieved.

[0125] Similarly, the light source controller 18 can be controlled such that the output of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is finely adjusted based on the detection result of a photodetector that detects the radiation intensity of the laser beam emitted from the light source, and the linearly modulated gray scale is changed to a corrected gray scale. Specifically, by generating a corrected current for driving the first laser element 111, the second laser element 112, and the third laser element 113 based on the detection result of the photodetector, the light source controller 18 controls the linearly modulated gray scale of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 to be corrected.

[0126] In addition, based on the detection result of a temperature sensor that measures the temperature of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the light source controller 18 can control the linearly modulated gray scale of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 to be corrected. Specifically, by generating a corrected current for driving the first laser element 111, the second laser element 112, and the third laser element 113 based on the detection result of the temperature sensor, the light source controller 18 controls the linearly modulated gray scale of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 to be corrected.

[0127] As described above, the light source in the image projection apparatus 1 according to the present embodiment includes the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, which can reduce the power consumption per unit time of each laser element, improve the heat dissipation characteristics, and further suppress the change in the oscillation threshold. Similarly, since the modulation frequency can be reduced, the power consumption of the driver can also be reduced.

[0128] Similarly, in the present embodiment, by configuring the light source 11 to include the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the scanning device 14 can reduce the resonance frequency in the main scanning direction and reduce the power consumption of the scanning device 14.

[0129] Similarly, in the present embodiment, by configuring the light source 11 to include the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, the image projection apparatus 1 can reduce the resonance frequency of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 in the main scanning direction, and by increasing θ opt to increase θ opt*D and project it onto the user's retina with a wide field of view (FOV). Therefore, the image projection device 1 can maintain a reduction in the resonance frequency in the main scanning direction of the scanning device 14 and the FOV projected onto the user's retina, increasing θ opt *D, thereby improving the resolution of the image projected onto the user's retina.

[0130] Similarly, in the present embodiment, since the light source 11 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, the image projection device 1 can reduce the resonance frequency in the main scanning direction according to the number of the first laser elements 111, the second laser elements 112, and the third laser elements 113, increasing θ opt and correspondingly increasing θ in Equation (1). opt *D, scan the laser beam, so as to be able to project a high-resolution image onto the user's retina. For this purpose, since the resonance frequency in the main scanning direction is proportional to the product of the frame rate and the vertical resolution, the image projection device 1 can, according to the number of the first laser elements 111, the second laser elements 112, and the third laser elements 113, improve the frame rate while maintaining the resonance frequency in the main scanning direction of the scanning device 14 and the resolution of the image projected onto the user's retina.

[0131] In addition, in the present embodiment, since the light source controller 18 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, the light source controller 18 controls the light source 11 such that the modulation frequency of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is lower than the modulation frequency of each laser element when one first laser element 111, one second laser element 112, and one third laser element 113 are provided. In this way, the light source 11 can improve the control accuracy of linear modulation and increase the number of bit gradations of the image projected onto the retina.

[0132] The first variant embodiment of the second embodiment

[0133] In the above second embodiment, since the light source 11 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, the modulation speed of each laser element can be reduced. That is, the modulation frequency can be lower than that in the first embodiment. Similarly, since the image projection device 1 is a device that projects an image onto the user's retina, the drive current of each laser element can be relatively small. Accordingly, when performing precise gray-scale control at low gray levels, waveform distortion or overshoot can be reduced by controlling a micro current and reducing the modulation speed while performing linear modulation. Accordingly, the gray scale of the image can be increased, and more space can be provided for laser output, thereby increasing the brightness and allowing precise control at high gray levels. Therefore, in the above second embodiment, the light source controller 18 can arbitrarily control the number of gray levels of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 such that the gray scale of the image projected onto the user's retina is greater than or equal to 12 bits and less than or equal to 16 bits. Similarly, the light source controller 19 can control the number of gray levels of linear modulation of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 to project a high dynamic range (HDR) image onto the user's retina such that the gray scale of the image projected onto the user's retina is greater than or equal to 12 bits and less than or equal to 16 bits. In particular, since the device is a device for an eye-tracking retina projection method, the gray scale or resolution of the image information corresponding to the line-of-sight direction can be improved, that is, the processing load of the image processing can be reduced by reducing the gray scale and resolution outside the line-of-sight direction.

[0134] Second variant embodiment of the second embodiment

[0135] Similarly, although in the second embodiment, the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 are all configured as VCSEL elements, the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 can also be configured as edge-emitting laser elements. In Figure 20In the illustrated embodiment, the emitter size ES1 of the first laser elements 111a - 111h is the distance between the emitter of the first laser element 111a and the center of the light emitting portion of the first laser element 111f. Similarly, similar to the emitter size ES1 of the first laser elements 111a - 111h, the emitter size ES2 of the second laser elements 112a - 112h is the distance between the emitter of the second laser element 112a and the center of the light emitting portion of the second laser element 112f, and the emitter size ES3 of the third laser elements 113a - 113h is the distance between the emitter of the third laser element 113a and the center of the light emitting portion of the third laser element 113f. Then, when the emitter size of one laser element is set to 1 μm, as Figure 21 shown, the emitter size for each pitch and each number of beams can be reduced to less than or equal to 90 μm. Similarly, as Figure 21 shown, the emitter size can be set to less than or equal to 30 μm, or less than or equal to 5 μm. Accordingly, even if each laser element is configured as an edge-emitting laser element, the emitter size can be reduced, and thus, the scanning device can be miniaturized, and θ opt *D can be increased.

[0136] Third Variant Embodiment of the Second Embodiment

[0137] In the above-described second embodiment, the image projection device 1 may include a beam deflector that deflects the optical axis of each laser beam emitted from one of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 by an arbitrary amount. Specifically, as Figure 22As shown, the light source 11 according to this modified embodiment includes a plurality of first laser elements 111a and 111b, a plurality of second laser elements 112a and 112b, a plurality of third laser elements 113a and 113b, first semiconductor chips 114a and 114b, second semiconductor chips 115a and 115b, third semiconductor chips 116a and 116b, a drive circuit 117, first collimating lenses 118a and 118b, second collimating lenses 119a and 119b, third collimating lenses 120a and 120b, a multiplexing optical system 121, a first beam deflector 122, a second beam deflector 123, a third beam deflector 124, a first mirror 125, a second mirror 126, a third mirror 127, a first wave plate 128, a second wave plate 129, a third wave plate 130, a first half mirror 131, a second half mirror 132, and a third half mirror 133. The configurations of the first semiconductor chips 114a and 114b, the second semiconductor chips 115a and 115b, the third semiconductor chips 116a and 116b, the drive circuit 117, the first collimating lenses 118a and 118b, the second collimating lenses 119a and 119b, the third collimating lenses 120a and 120b, and the multiplexing optical system 121 are similar to those of the second embodiment described above, and thus will not be described in detail. Each of the first laser element 111, the second laser element 112, and the third laser element 113 may include a semiconductor substrate. In this case, preferably, the semiconductor substrate is disposed, for example, between a first high-reflection DBR and a second high-reflection DBR sandwiching an active layer. The semiconductor substrate is not limited to this structure and may also be disposed outside one of the first high-reflection DBR and the second high-reflection DBR.

[0138] The plurality of first laser elements 111a, 111b are included on the first semiconductor chips 114a, 114b. Similarly, the plurality of second laser elements 111a, 111b are included on the second semiconductor chips 115a, 115b. Further, the plurality of third laser elements 113a, 113b are included on the third semiconductor chips 116a, 116b.

[0139] The first beam deflector 122 is an optical element for deflecting the optical axis of the laser beam emitted from the first laser element 111a. Similarly, the second beam deflector 123 is an optical element for deflecting the optical axis of the laser beam emitted from the second laser element 112a. Additionally, the third beam deflector 124 is an optical element for deflecting the optical axis of the laser beam emitted from the third laser element 113a. Each beam deflector may use a diffractive optical system such as an inclined glass substrate, a biaxial crystal LiNbO3, or a metamaterial.

[0140] Specifically, as Figure 23As shown, the first beam deflector 122, the second beam deflector 123, and the third beam deflector 124 deflect the optical axis of the incident laser beam by refracting and emitting the incident laser beam. The first beam deflector 122, the second beam deflector 123, and the third beam deflector 124 adjust the deflection amount of the optical axis of the laser beam by changing the tilt based on the control of the light source controller 18. The first beam deflector 122, the second beam deflector 123, and the third beam deflector 124 have the same deflection amount for the laser beam.

[0141] The first mirror 125 is a mirror that reflects the laser beam emitted by the first beam deflector 122 to the first half mirror 131; the second mirror 126 is a mirror that reflects the laser beam emitted by the second beam deflector 123 to the second half mirror 132; the third mirror 127 is a mirror that reflects the laser beam emitted by the third beam deflector 124 to the third half mirror 133.

[0142] The first wave plate 128 is arranged between the first laser element 111b and the first half mirror 131, and is an element for changing the polarization direction of the laser beam emitted from the first laser element 111b; the second first wave plate 129 is located between the second laser element 112b and the second half mirror 132, and is an element for changing the polarization direction of the laser beam emitted from the second laser element 112b; the third wave plate 130 is arranged between the third laser element 113b and the third half mirror 133, and is an element for changing the polarization direction of the laser beam emitted from the third laser element 113b.

[0143] The first half mirror 131 is arranged between the first mirror 125, the first wave plate 128, and the multiplexing optical system 121, reflects the laser beam of the first laser element 111a reflected by the first mirror 125 to the multiplexing optical system 121, and allows the laser beam of the first laser element 111b passing through the first wave plate 128 to pass through the multiplexing optical system 121.

[0144] The second half mirror 132 is arranged between the second mirror 126, the second wave plate 129, and the multiplexing optical system 121, reflects the laser beam of the second laser element 112a reflected by the second mirror 126 to the multiplexing optical system 121, and allows the laser beam of the second laser element 112b passing through the second wave plate 129 to pass through the multiplexing optical system 121.

[0145] The third half mirror 133 is arranged between the third mirror 127, the third wave plate 130, and the multiplexing optical system 121, reflects the laser beam of the third laser element 113a reflected by the third mirror 127 to the multiplexing optical system 121, and allows the laser beam of the third laser element 113b passing through the third wave plate 130 to pass through the multiplexing optical system 121.

[0146] Taking the first laser elements 111a and 111b in the light source 11 as an example, the laser beam emitted from the first laser element 111a passes through the first collimating lens 118a, the optical axis of the laser beam is deflected in the beam deflector 122, reflected by the first mirror 125, and then incident on the first half mirror 131. On the other hand, the laser beam emitted from the first laser element 11b passes through the first wave plate 128 and is incident on the first half mirror 131. In the first half mirror 131, regarding the reflection position of the laser beam emitted from the first laser element 111a and the passing position of the laser beam emitted from the first laser element 111b, for example, if the optical axis of the laser beam of the first laser element 111 is not deflected by the first beam deflector 122, the two are located at the same position; if the optical axis of the laser beam of the first laser element 111a is deflected by the first beam deflector, there is a distance between the laser beams of the first laser element 111a and the first laser beam 111b. Therefore, in the light source 11 according to this modified embodiment, the separation of the laser beams of each laser element can be controlled by changing the inclination of the beam deflector. This embodiment is given for VCSEL, but the beam deflector can be used for ordinary edge-emitting semiconductor lasers.

[0147] It should be noted that in the third modified embodiment of the second embodiment, the light source 11 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, and one beam deflector is provided for the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113; however, a plurality of beam deflectors can also be provided for the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113. Specifically, as Figure 24 shown, the light source 11 may include: a plurality of first beam deflectors 125, which are used to deflect each laser beam emitted from the plurality of first laser elements 111 and are arranged between each first laser element 111 and the multiplexing optical system 121; a plurality of second beam deflectors 126, which are used to deflect each laser beam emitted from the plurality of second laser elements 112 and are arranged between each second laser element 112 and the multiplexing optical system 121; and a plurality of third beam deflectors 127, which are used to deflect each laser beam emitted from the plurality of third laser elements 113 and are arranged between each third laser element 113 and the multiplexing optical system 121. According to such a configuration, the imaging projection device 1 can control the first beam deflector 125, the second beam deflector 126, and the third beam deflector 127, for example, to shorten the distances of the emitter sizes ES1, ES2, and ES3 to less than or equal to 5μm - 30μm and reduce the distance between the beams.

[0148] The fourth modified embodiment of the second embodiment

[0149] In the above second embodiment, the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 are arranged in one direction along each semiconductor substrate. However, the arrangement of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is not limited thereto. The plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 may be arranged two-dimensionally. Hereinafter, taking the plurality of first laser elements 111 as an example, the specific structure of this modified embodiment will be described. As Figure 25 shown, the plurality of first laser elements 111 according to this modified embodiment include four first laser elements 111a - 111d, and the four first laser elements 111a - 111d are two-dimensionally arranged at a predetermined distance d1 in the first direction and a predetermined distance d2 in the second direction. In Figure 25 the embodiment shown, the first direction is the main scanning direction, and the second direction is the sub-scanning direction. Specifically, the four first laser elements 111a - 111d are arranged in a zigzag shape such that each of the four first laser elements 111a - 111d is in contact with each other. In Figure 25 , the emitter ranges that emit laser beams 111a1 - 111d1 in the first laser elements 111a - 111d are schematically represented by a circle C1. Additionally, in Figure 25 , the entire range of the elements in the first laser elements 111a - 111d, which includes the wirings near the emitter, is schematically represented by a circle C2 surrounding the circle C1. The meanings of the circles C1 and C2 are similar to those in Figure 27 and Figure 28 , which will be described hereinafter. Since the first laser elements 111a - 111d are arranged in a zigzag shape, the distance (i.e., pitch) between the centers of the light-emitting portions of the first laser elements 111a - 111d can be made as small as possible. Even if the first laser elements 111a - 111d are distributed near the emitter, an arbitrary pitch can be created.

[0150] Arrange the first laser elements 111a - 111d as follows. As Figure 26 shown, the light source controller 18 drives the first laser elements 111b, 111d with a first input signal and drives the first laser elements 111a, 111c with a second input signal whose phase is delayed with respect to the first input signal through linear modulation. In this way, as Figure 27 shown, even if the plurality of first laser elements 111 are arranged in a manner deviating from the main scanning direction (the first scanning direction), since the laser beams 111a1 - 111d1 emitted by each laser element do not deviate from the main scanning direction, when projecting an image onto the user's retina, a high-resolution image can still be projected onto the user's retina.

[0151] In addition, similarly, a plurality of second laser elements 112 and a plurality of third laser elements 113 can also be arranged in a zigzag pattern so that each of the plurality of second laser elements 112 and third laser elements 113 is in contact with each other. In addition, similar to the plurality of first laser elements 111, the light source controller 18 uses linear modulation to drive each second laser element 112 and each third laser element 113.

[0152] In this way, by two-dimensionally arranging a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113 such that they are spaced apart by a predetermined distance d1 in the first direction and a predetermined distance d2 in the second direction, even if the light source 11 includes a plurality of laser elements, miniaturization of the light source 11 can be achieved. Similarly, by arranging the plurality of second laser elements 112 and the plurality of third laser elements 113 in a zigzag pattern and arranging the first laser elements 111a - 111d in contact with each other, the light source 11 can be further miniaturized.

[0153] In addition, in the light source 11 according to the present embodiment, the plurality of first laser elements 111 are arranged in contact with each other, but the first laser elements 111a - 111d can also be arranged in a zigzag pattern without being in contact with each other. Similarly, the plurality of second laser elements 112 and the plurality of third laser elements can also be arranged in a zigzag pattern, and the second laser elements 112a - 112d and the third laser elements 113a - 113d are not in contact with each other. Similarly, in the light source 11 of the present embodiment, the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 each include four laser elements, but the number of laser elements is not limited to four. That is, the number of laser elements is arbitrary and can include two or three, or more than or equal to 5. Specifically, as Figure 28 shown, the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 can arrange six laser elements in a zigzag pattern such that each laser element is in contact with each other. Compared with Figure 25 the embodiment of Figure 28 the embodiment of opt further shortens the distance between the centers of the light emitting portions, and thus the light source can be further miniaturized without increasing the size D of the MEMS; therefore, the resonance frequency in the main scanning direction can be reduced by multi-beams, increasing θ opt *D and increasing θ

[0154] First variant embodiments of the first and second embodiments

[0155] In the above first and second embodiments, the multiplexing optical system 121 includes a first reflective optical system 1211, a second reflective optical system 1212, and a third reflective optical system 1213, but the embodiments are not limited thereto. That is, there are cases where the first reflective optical system 1211, the second reflective optical system 1212, and the third reflective optical system 1213 can be integrated into one body. As Figure 29 shown, the multiplexing optical system 121a may include: a first reflector 1211a for reflecting the laser beam emitted from the first laser element 111 toward the scanning device 14; a second reflector 1212a for reflecting the laser beam emitted from the second laser element 112 toward the scanning device 14; and a third reflector 1213a for reflecting the laser beam emitted from the first laser element 111 toward the scanning device 14 and configured to multiplex the respective laser beams emitted from the first reflector 1211a, the second reflector 1212a, and the third reflector 1213a on the same optical axis. Additionally, in Figure 29 the embodiment shown, the light source 11 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, but the light source 11 may also include one first laser element 111, one second laser element 112, and one third laser element 113.

[0156] Second variant embodiments of the first and second embodiments

[0157] Similarly, as Figure 30 shown, the multiplexing optical system 121 can also be configured as a cross prism. When the multiplexing optical system 121 is configured as a cross prism, as Figure 30 shown, the drive circuit 117 is included on each of the first laser element 111, the second laser element 112, and the third laser element 113. It should be noted that in Figure 30 the embodiment shown, the first laser element 111, the second laser element 112, and the third laser element 113 each include one laser element, but they may also each include a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113.

[0158] Third variant embodiments of the first and second embodiments

[0159] It should be noted that the light source 11 may include a heat dissipation plate for dissipating the heat generated by the first laser element 111, the second laser element 112, and the third laser element 113. Specifically, as Figure 31 shown, the light source 11 in addition to Figure 5In addition to the structure of the light source 11 shown, it further includes a first heat sink 137, a second heat sink 138, and a third heat sink 139.

[0160] The drive circuit 117 is a circuit that drives each of the first laser element 111, the second laser element 112, and the third laser element 113. As Figure 25 shown, the drive circuit 117 is arranged on the opposite side of the emission direction of each of the first laser element 111, the second laser element 112, and the third laser element 113.

[0161] The first heat sink 137 is arranged to be in contact with the surface opposite to the surface where the first laser element 111 is located in the drive circuit 117, the second heat sink 138 is arranged to be in contact with the output side surface of the second laser element 112, and the third heat sink 139 is arranged to be in contact with the output side surface of the third laser element 113. Additionally, as Figure 31 shown, the second heat sink 138 and the third heat sink 139 may have holes 138a, 139a for emitting laser beams.

[0162] It should be noted that in Figure 31 the embodiment shown, the first laser element 111, the second laser element 112, and the third laser element 113 each include one laser element, but may also each include a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113.

[0163] The fourth variant embodiment of the first embodiment and the second embodiment

[0164] In addition, the light source 11 may be arranged such that the first laser element 111 is disposed on the drive circuit 117, the second laser element 112 is disposed on the first laser element 111, and the third laser element 113 is disposed on the second laser element 112. The arrangement order of the first laser element 111, the second laser element 112, and the third laser element 113 is in ascending order of bandgap size. With such a structure, relatively large emitter sizes can be achieved with a small device size while achieving high resolution. It should be noted that in Figure 32 the embodiment shown, the light source 11 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, but may also include one first laser element 111, one second laser element 112, and one third laser element 113.

[0165] The third embodiment

[0166] In the above-described first embodiment, the light source 11 multiplexes the laser beams respectively emitted from the first laser element 111, the second laser element 112, and the third laser element 113 by including a multiplexing optical system 121. However, the multiplexing method of the laser beams is not limited to the multiplexing optical system. In the third embodiment, the light source 11 may multiplex the laser beams respectively emitted from the first laser element 111, the second laser element 112, and the third laser element 113 by including a waveguide-type optical multiplexer. The following will describe the parts different from the above-described first embodiment.

[0167] As Figure 33 shown, the light source 11 of the present embodiment includes a first laser element 111, a second laser element 112, a third laser element 113, a drive circuit 117, and a waveguide-type optical multiplexer 134.

[0168] In the present embodiment, the first laser element 111, the second laser element 112, and the third laser element 113 are VCSELs or edge-emitting laser elements.

[0169] The drive circuit 117 is a circuit that drives each of the first laser element 111, the second laser element 112, and the third laser element 113. As Figure 33 shown, the drive circuit 117 is arranged on the opposite side of the emission direction of each of the first laser element 111, the second laser element 112, and the third laser element 113.

[0170] The waveguide-type optical multiplexer 134 has waveguides 1341 - 1343 and an output port 1344.

[0171] The waveguides 1341 - 1343 propagate the laser beams respectively emitted from the first laser element 111, the second laser element 112, the third laser element 113, and the drive circuit 117, and multiplex the laser beams respectively emitted from the first laser element 111, the second laser element 112, and the third laser element 113 in a multiplexing region 1345 where the propagated laser beams are multiplexed.

[0172] The output port 1344 emits the laser beam multiplexed at the multiplexing region 1345 to the scanning device 14 side.

[0173] As described above, in the image projection device 1 according to the above-described third embodiment, since the image projection device 1 is an eye-tracking retinal projection type device that can detect the user's line-of-sight direction and project an image onto the user's retina according to the detected line-of-sight direction, even if the light source 11 uses a waveguide-type optical multiplexer 134, the light source 11 can suppress the output of the laser beam similarly to the first embodiment, operate at a low threshold current, be driven with low power consumption, and at the same time achieve stable operation without the threshold current value being changed due to self-heating.

[0174] Similarly, in the above-described third embodiment, when the first laser element 111, the second laser element 112, and the third laser element 113 are VCSEL elements, the wavelength hardly changes even when the drive current value is changed, and the image projection apparatus 1 can achieve high color reproducibility.

[0175] Similarly, in the above-described third embodiment, since the drive circuit 117 is arranged to be in contact with the opposite surface of the integrated surface of the first semiconductor substrate 114, the second semiconductor 115, and the third semiconductor 116, similar to the first embodiment, the capacitance can be reduced, and the first laser element 111, the second laser element 112, and the third laser element 113 can be linearly modulated quickly, the output stability of each laser element can be achieved at low gray levels, high brightness of the image projected onto the user's retina can be achieved at high gray levels, and a high speed for achieving not only 10-bit gray levels but also 16-bit gray levels can be achieved. In addition, the power consumption can be reduced by reducing the adjacent resolution, which enables the image projection apparatus 1 to maintain low power consumption even when 16-bit gray levels are achieved.

[0176] Fourth Embodiment

[0177] In the above-described third embodiment, the light source 11 includes one waveguide type optical multiplexer, but the configuration of the light source 11 is not limited thereto. In the fourth embodiment, a plurality of waveguide type optical multiplexers 134 can be used. The following will describe the parts different from the above-described third embodiment.

[0178] As Figure 34 shown, the light source 11 of the present embodiment includes a first laser element 111a of the first group, a second laser element 112a of the second group, a third laser element 113a of the third group, a first group drive circuit 117a, a first group waveguide type optical multiplexer 134a, a first laser element 111b of the second group, a second laser element 112b of the second group, a third laser element 113b of the second group, a second group drive circuit 117b, and a second group waveguide type optical multiplexer 134b.

[0179] In the present embodiment, the first laser element 111a, the second laser element 112a, and the third laser element 113a of the first group are VCSELs or edge-emitting laser elements.

[0180] The first group drive circuit 117a is a circuit that drives each of the first laser element 111a, the second laser element 112a, and the third laser element 113a of the first group. As Figure 34 shown, the drive circuit 117a is arranged on the opposite side of the emission direction of each of the first laser element 111a, the second laser element 112a, and the third laser element 113a of the first group.

[0181] The first group of waveguide optical multiplexers 134a multiplex the laser light emitted from the first laser element 111a, the second laser element 112a, and the third laser element 113a of the first group in the multiplexing region 1345a of the waveguides 1341a - 1343a, and emit the first multiplexed light beam from the output port 1344a.

[0182] The first laser element 111b, the second laser element 112b, and the third laser element 113b of the second group are the same as the first laser element 111a, the second laser element 112a, and the third laser element 113a of the first group, and are all VCSELs or edge-emitting laser elements.

[0183] The second group of drive circuits 117b is a circuit that drives each of the first laser element 111b, the second laser element 112b, and the third laser element 113b of the second group. As Figure 34 shown, the drive circuits 117b are arranged on the opposite side of the emission direction of each of the first laser element 111b, the second laser element 112b, and the third laser element 113b of the second group.

[0184] The second group of waveguide optical multiplexers 134b multiplex the laser light emitted from the first laser element 111b, the second laser element 112b, and the third laser element 113b of the second group in the multiplexing region 1345b of the waveguides 1341b - 1343b, and emit the second multiplexed light beam from the output port 1344b.

[0185] As Figure 34 shown, in the light source 11 according to the present embodiment, by arranging the first laser element 111a, the second laser element 112a, the third laser element 113a of the first group and the first laser element 111b, the second laser element 112b, the third laser element 113b of the first group in one direction, the first group of waveguide optical multiplexers 134a and the second group of waveguide optical multiplexers 134b are arranged such that the emission positions of the first multiplexed light beam and the second multiplexed light beam are close to each other. At this time, the emitter size ES, that is, the distance between the center of the output port 1347a of the first group of waveguide optical multiplexers 134a and the center of the output port 1347b of the second group of waveguide optical multiplexers 134b, is preferably less than or equal to 90 μm. Similarly, the emitter size ES, that is, the distance between the center of the output port 1347a of the first group of waveguide optical multiplexers 134a and the center of the output port 1347b of the second group of waveguide optical multiplexers 134b, is more preferably less than or equal to 30 μm, and further preferably less than or equal to 5 μm. In particular, since there is no thermal interference in the waveguide optical multiplexer, this distance can be shortened.

[0186] Note that the waveguides 1341a - 1343a of the waveguide type optical multiplexer 134a and the waveguides 1341b - 1343b of the waveguide type optical multiplexer 134b can also be changed to be as Figure 34 shown, such that compared with the waveguides 1341 - 1343 of the waveguide type optical multiplexer 134 of the third embodiment shown in Figure 34 the waveguides from the multiplexing regions 1345a, 1345b to the output ports 1344a, 1344b have sharp bends. Since the image projection device 1 according to the present embodiment is an eye-tracking retinal projection type, the output of each laser element can be less than or equal to 1 mW. Therefore, even if there is a loss of the laser beam due to the sharp bends on the waveguide, the image can still be projected onto the user's retina. In addition, laser beam loss can be introduced by setting sharp bends on the waveguide, and the first multiplexed beam and the second multiplexed beam with high current can be used to avoid the warping effect that may occur with a low threshold current.

[0187] Note that the configuration method of the first group of waveguide type optical multiplexers 134a and the second group of waveguide type optical multiplexers 134b is not limited to this. As Figure 35 shown, the light source 11 according to the present embodiment can be configured such that the first multiplexed beam and the second multiplexed beam are emitted at positions close to each other by the first laser elements 111a, second laser elements 112a, and third laser elements 113a of the first group facing each other and the first laser elements 111b, second laser elements 112b, and third laser elements 113b of the second group. Additionally, at this time, the emitter size ES, that is, the distance between the centers of the output ports 1344a of the first group of waveguide type optical multiplexers 134a and the output ports 1344b of the second group of waveguide type optical multiplexers 134b, is preferably 90 μm or less. Similarly, the emitter size ES, that is, the distance between the centers of the output ports 1344a of the first group of waveguide type optical multiplexers 134a and the output ports 1344b of the second group of waveguide type optical multiplexers 134b, is more preferably less than or equal to 30 μm, and further preferably less than or equal to 5 μm. Note that the image projection device 1 can also be equipped with a micro beam deflector to control the distance between the spacings by controlling the micro beam deflector at any interval. Specifically, the optical axis of the first multiplexed beam emitted from the first group of waveguide type optical multiplexers 134a or the optical axis of the second multiplexed beam emitted from the second group of waveguide type optical multiplexers 134b can be deflected to reduce the distance between the output ports 1344a and 1344b to less than or equal to 5 μm.

[0188] Similarly, the scanning device 14 can increase the optical swing angle θ opt by reducing the resonance frequency in the main scanning direction, thereby increasing θ in Equation (1) opt*D to achieve a higher resolution and scan the laser beam according to the number of each of the first laser element 111, the second laser element 112, and the third laser element 113. Specifically, as Figure 8 and Figure 17 shown, when scanning the laser beam emitted from the exit port 1344a of the first group of waveguide type optical multiplexers 134a and the exit port 1344b of the second group of waveguide type optical multiplexers 134b, compared with the case where the waveguide type optical multiplexer 134 scans a single laser beam, the scanning device 14 can reduce the resonance frequency of the MEMS and increase θ opt *D in Equation (1), thereby improving the resolution of the image projected onto the user's retina. That is, when the scanning device 14 scans the laser beam emitted from the exit port 1344a of the first group of waveguide type optical multiplexers 134a and the exit port 1344b of the second group of waveguide type optical multiplexers 134b, when the resolution of the image projected onto the user's retina is the same, as the number of laser elements increases, θ opt *D in Equation (1) increases, the resolution improves, the modulation frequency of the laser element decreases, and the resonance frequency in the main scanning direction may decrease. Similarly, according to the light source 11 of the present embodiment, which includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, the first group of waveguide type optical multiplexers 134a and the second group of waveguide type optical multiplexers 134b are arranged such that the emission positions of the first multiplexed beam and the second multiplexed beam are close to each other. For this purpose, by configuring the first group of waveguide type optical multiplexers 134a and the second group of waveguide type optical multiplexers 134b such that the exit positions of the first multiplexed beam and the second multiplexed beam are close to each other, the scanning device 14 reduces the resonance frequency in the main scanning direction and increases the optical swing angle θ opt , and correspondingly increases θ opt *D of Equation (1); the scanning device scans the laser beam by the raster scanning method, thereby projecting an image onto the user's retina at a resolution higher than HD, for example, HD, FHD, 2K, and 4K resolutions.

[0189] Since the light source 11 according to the present embodiment includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, the light source 11 is controlled such that, according to the number of each of the first laser elements 111, the second laser elements 112, and the third laser elements 113, the modulation frequency of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is lower than the modulation frequency when including one first laser element 111, one second laser element 112, and one third laser element 113. Specifically, in the case of the equivalent frequency, for example, when using one first laser element 111, one second laser element 112, and one third laser element 113 to project an image at FHD resolution and 120 Hz frame rate, each of the first laser element 111, the second laser element 112, and the third laser element 113 needs to be controlled with a modulation frequency of 1920 * 1080 * 120 = 250 MHz; while when using two first laser elements 111, two second laser elements 112, and two third laser elements 113 to project an image at FHD resolution and 120 Hz frame rate, 250 MHz / 2 = 125 MHz is sufficient to control the two first laser elements 111, the two second laser elements 112, and the two third laser elements 113. That is to say, as Figure 36 shown, since the light source controller 18 includes a plurality of first laser elements 111, second laser elements 112, and third laser elements 113, the modulation frequency of the input signal output to each laser element based on the image data is reduced.

[0190] Similarly, the light source controller 18 can be controlled such that, based on the detection result of a photodetector that detects the radiation intensity of the laser beam emitted from the light source 11, the output of each of the first laser elements 111, the second laser elements 112, and the third laser elements 113 is finely adjusted to change the linearly modulated gray scale to a corrected gray scale. Specifically, by generating a correction current for driving the first laser elements 111, the second laser elements 112, and the third laser elements 113 based on the detection result of the photodetector, the light source controller 18 controls the linearly modulated gray scale of each of the first laser elements 111, the second laser elements 112, and the third laser elements 113.

[0191] In addition, based on the detection results of temperature sensors that measure the temperatures of each of the first laser element 111, the second laser element 112, and the third laser element 113, the light source controller 18 can finely adjust the outputs of the first laser element 111, the second laser element 112, and the third laser element 113 so that the linearly modulated gray levels become corrected gray levels. Specifically, by generating correction currents for driving the first laser element 111, the second laser element 112, and the third laser element 113 based on the detection results of the temperature sensors, the light source controller 18 controls the linearly modulated gray levels of each of the first laser element 111, the second laser element 112, and the third laser element 113.

[0192] As described above, the light source 11 in the image projection device 1 according to the present embodiment includes a plurality of waveguide-type optical multiplexers, which can reduce the power consumption per unit time of each laser element, improve the heat dissipation characteristics, and further suppress changes in the oscillation threshold. Similarly, since the modulation frequency can be reduced, the power consumption of the driver can also be reduced.

[0193] Similarly, since the light source 11 in the image projection device 1 according to the present embodiment employs waveguide-type optical multiplexers, the multiplexed laser beams from the first laser element 111, the second laser element 112, and the third laser element 113 are emitted from one exit port, so the laser beams hardly shift.

[0194] Similarly, in the image projection device 1 of the present embodiment, since the first set of waveguide-type optical multiplexers 134a and the second set of waveguide-type optical multiplexers 134b are arranged such that the emission positions of the first multiplexed light beam and the second multiplexed light beam are close to each other, the scanning device 14 can reduce the resonance frequency in the main scanning direction, increase θopt, increase θopt * D, thereby improving the resolution of the image projected onto the user's retina.

[0195] Similarly, in the present embodiment, by making the light source 11 include a plurality of waveguide-type optical multiplexers, the resonance frequency of the scanning device 14 can be reduced, so the power consumption of the scanning device 14 can be reduced.

[0196] Similarly, in the present embodiment, since the light source 11 includes a plurality of waveguide-type optical multiplexers, the image projection device 1 can reduce the resonance frequency in the main scanning direction of the scanning device 14 according to the number of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113, and increase θ opt and increase θ opt * D, and project onto the user's retina at a wide field of view (FOV). For this purpose, the image projection device 1 can increase θ while maintaining the resonance frequency in the main scanning direction of the scanning device 14 and the FOV of the image projected onto the user's retina. opt*D to improve the resolution of the image projected onto the user's retina.

[0197] Similarly, in the present embodiment, since the light source 11 includes a plurality of waveguide type optical multiplexers, the image projection device 1 can reduce the resonance frequency in the main scanning direction and increase θ in Equation (1) according to the number of the first laser element 111, the second laser element 112, and the third laser element 113. opt *D projects a high-resolution image onto the user's retina. To this end, since the resonance frequency in the main scanning direction is proportional to the product of the frame rate and the vertical resolution, the image projection device 1 can maintain the resonance frequency in the main scanning direction of the scanning device 14 and the resolution of the image projected onto the user's retina according to the number of the first laser element 111, the second laser element 112, and the third laser element 113 to increase the frame rate.

[0198] In addition, in the present embodiment, since the light source controller 18 includes a plurality of first laser elements 111, a plurality of second laser elements 112, and a plurality of third laser elements 113, the light source controller 18 controls the light source 11 such that the modulation frequency of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 is lower than the modulation frequency of each laser element when one first laser element 111, one second laser element 112, and one third laser element 113 are set. In this way, the light source 11 can improve the control accuracy of linear modulation and increase the number of bit gradation of the image projected onto the retina.

[0199] Variant Embodiment of the Fourth Embodiment

[0200] In the above fourth embodiment, since the light source 11 includes a plurality of first laser elements 111, second laser elements 112, and third laser elements 113, the modulation speed of each laser element can be reduced. Similarly, since the image projection device 1 is a device that projects an image onto the user's retina, the drive current of each laser element can be small, and precise gray scale control can be performed at low gray scales. By performing micro-current control during linear modulation, waveform distortion or overshoot can be reduced, thereby improving the gray scale of the image. Since the space for laser output is larger, precise control can be performed at high gray scales, thereby improving the brightness. Accordingly, in the fourth embodiment, the light source controller 18 can arbitrarily control the number of gray scales of linear modulation of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 such that the gray scale of the image projected onto the user's retina is greater than or equal to 12 bit and less than or equal to 16 bit.

[0201] Further, the light source controller 18 can control the modulation frequency of each of the plurality of first laser elements 111, the plurality of second laser elements 112, and the plurality of third laser elements 113 to project a high dynamic range (HDR) image onto the user's retina, such that the gray scale of the image projected onto the user's retina is greater than or equal to 12 bits and less than or equal to 16 bits. In particular, since the device is a device for the eye-tracking retina projection method, the gray scale or resolution of the image information corresponding to the line-of-sight direction can be increased, that is, the image processing load is reduced by reducing the gray scale and resolution outside the line-of-sight direction.

[0202] Variant embodiments of the third and fourth embodiments

[0203] As Figure 37 shown, the waveguide type optical multiplexers 134, 134a, and 134b in the above third and fourth embodiments may include: a first waveguide 1346 for incident laser beams of the first laser element 111; a second waveguide for incident laser beams of the second laser element 112; a third waveguide 1348 for incident laser beams of the third laser element 113; a first multiplexer 1349 for propagating laser beams between the first waveguide and the second waveguide; and a second multiplexer 1350 for propagating laser beams between the third waveguide and the first waveguide.

[0204] Note that the above drawings, especially Figure 13 and Figure 29 , are diagrams depicting an overview of how each optical system and each laser element are arranged. The actual sizes and configurations of each optical system and each laser element shown in the figures may be different.

[0205] In the description of the embodiments of the present disclosure, it should be understood that terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" should be construed as referring to the directions or positions described or shown in the accompanying drawings being discussed. These relative terms are only used to simplify the description of the present disclosure and do not indicate or imply that the device or element referred to must have a specific direction, or be constructed or operated in a specific direction. Therefore, these terms should not be construed as limiting the present disclosure.

[0206] In addition, terms such as "first" and "second" are used herein for descriptive purposes and do not denote or imply relative importance or significance, nor do they imply the number of indicated technical features. Thus, features defined by "first" and "second" may include one or more of such features. In the description of the present disclosure, unless otherwise specified, "a plurality of" means two or more.

[0207] In the description of the disclosed embodiments, unless otherwise specified or restricted, terms such as "mounted", "connected", "coupled", etc. are used broadly. For example, it may be a fixed connection, a detachable connection or an integral connection, may also be a mechanical or electrical connection, may also be a direct connection or an indirect connection through an intermediate structure, and may also be the internal communication of two elements. Those skilled in the art can understand according to specific circumstances.

[0208] In the embodiments of the present disclosure, unless otherwise specified or restricted, the structure in which the first feature is "on" or "under" the second feature may include embodiments in which the first feature is in direct contact with the second feature, and may also include embodiments in which the first feature and the second feature are not in direct contact, but are in contact through additional features formed therebetween. In addition, the first feature being "on", "above" or "at the top of" the second feature may include embodiments in which the first feature is upright or inclined "on", "above" or "at the top of" the second feature, or merely means that the height of the first feature is higher than the height of the second feature. The first feature being "under", "below" or "at the bottom of" the second feature may include embodiments in which the first feature is upright or inclined "under", "below" or "at the bottom of" the second feature, or merely means that the height of the first feature is lower than the height of the second feature.

[0209] The above description provides various embodiments and examples to implement different structures of the present disclosure. To simplify the present disclosure, certain elements and arrangements are described above. However, these elements and arrangements are only illustrative and are not intended to limit the present disclosure. In addition, reference numerals and / or letters of reference numerals may be repeated in different embodiments of the present disclosure. This repetition is for simplicity and clarity and does not denote the relationship between different embodiments and / or arrangements. In addition, the present disclosure also provides embodiments of different processes and materials. However, those skilled in the art can understand that other processes and / or materials may also be employed.

[0210] As used throughout the specification, "embodiment", "some embodiments" or "exemplary embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics related to the embodiment or example are included in at least one embodiment or example of the present application. Therefore, the appearance of the above phrases throughout the specification does not necessarily refer to the same embodiment or example of the present disclosure. In addition, in one or more embodiments or examples, the specific features, structures, materials or characteristics may be combined in any suitable manner.

[0211] Any process or method described in the flowchart or otherwise described herein can be understood to include one or more modules, segments or portions of code for executable instructions for implementing specific logical functions or steps in the process, and the scope of the preferred embodiments of the present disclosure includes other implementations, wherein those skilled in the art should understand that the functions can be implemented in an order different from the order shown or discussed, including in substantially the same order or in the reverse order.

[0212] The logic and / or steps described otherwise herein or shown in the flowchart, for example, a specific sequence list of executable instructions for implementing a logical function, can be specifically implemented in any computer-readable medium used by an instruction execution system, apparatus or device (such as a computer-based system, a system including a processor, or other systems capable of obtaining instructions from the instruction execution system, apparatus or device and executing the instructions), or used in combination with the instruction execution system, apparatus or device. For the purposes of this specification, a "computer-readable medium" can be any device suitable for containing, storing, communicating, propagating or transmitting a program for use by or in connection with an instruction execution system, apparatus or device. More specific examples of computer-readable media include, but are not limited to: electronic connections (electronic devices) having one or more wires, portable computer enclosures (magnetic devices), random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM, or flash memory), fiber optic devices, and portable compact disk read-only memory (CDROM). In addition, a computer-readable medium can even be paper or other suitable media on which a program can be printed, because, for example, the paper or other suitable media can be optically scanned and, when necessary to obtain the program electronically, edited, decrypted or processed by other suitable methods, and then the program can be stored in a computer memory.

[0213] It should be understood that each part of the present disclosure can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by an appropriate instruction execution system. For example, if implemented by hardware, in another embodiment, the steps or methods can be implemented by one or a combination of the following techniques known in the art: discrete logic circuits having logic gate circuits for implementing the logical functions of data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0214] Those skilled in the art should understand that all or part of the steps in the above exemplary methods of the present disclosure can be implemented by using program commands to relevant hardware. The program can be stored in a computer-readable storage medium, and when the program is run on a computer, the program includes a combination of one or more steps in the method embodiments of the present disclosure.

[0215] In addition, each functional unit of the embodiments of the present disclosure can be integrated into a processing module, or these units can exist separately physically, or two or more units can be integrated into one processing module. The integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, the integrated module can be stored in a computer-readable storage medium.

[0216] The above storage medium can be a read-only memory, a disk, a CD, etc.

[0217] Although the embodiments of the present disclosure have been shown and described, those skilled in the art should understand that these embodiments are exemplary and should not be construed as limiting the present disclosure, and the embodiments can be changed, modified, substituted, and varied without departing from the scope of the present disclosure.

Claims

1. An image projection device, comprising: A light source that emits a laser beam; A scanning device for scanning the laser beam emitted from the light source; A projection optical system for irradiating the laser beam scanned by the scanning device and projecting an image onto the retina of a user; A line-of-sight direction detector for detecting the line-of-sight direction of the user onto whom the image is projected; And An optical system controller for controlling the projection optical system based on the line-of-sight direction detected by the line-of-sight direction detector; Wherein, the light source includes: At least one first laser element for emitting a laser of a first color, At least one second laser element for emitting a laser of a second color different from the first color, and At least one third laser element for emitting a laser of a third color different from the first color and the second color.

2. The image projection device according to claim 1, wherein, Each of the first laser element, the second laser element, and the third laser element is a vertical cavity surface emitting laser (VCSEL) element.

3. The image projection device according to claim 1, wherein, Each of the first laser element, the second laser element, and the third laser element is an edge-emitting laser element.

4. The image projection device according to claim 1, wherein: The first color is red; The second color is green; and The third color is blue.

5. The image projection device according to claim 1, wherein: The wavelength of the first laser element is 650 nm; The wavelength of the second laser element is 520 nm; and The wavelength of the third laser element is 450 nm.

6. The image projection device according to claim 1, wherein: The first laser element has a first active layer; The second laser element has a second active layer; The third laser element has a second active layer; The first active layer includes aluminum gallium indium phosphide (InGaAlP); and The second active layer and the third active layer include indium gallium nitride (InGaN).

7. The image projection apparatus according to claim 1, wherein, The optical output power of each of the first laser element, the second laser element, and the third laser element is less than or equal to 1 mW.

8. The image projection apparatus according to claim 1, wherein, The threshold current of each of the first laser element, the second laser element, and the third laser element is less than or equal to 6 mA.

9. The image projection apparatus according to claim 1, wherein, The threshold current of each of the first laser element, the second laser element, and the third laser element is less than or equal to 1 mA.

10. The image projection device according to claim 1, wherein, The light source includes a plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements.

11. The image projection device according to claim 1, wherein, The light source includes a plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; and A plurality of the first laser elements are integrated on the same semiconductor substrate, a plurality of the second laser elements are integrated on the same semiconductor substrate, and a plurality of the third laser elements are integrated on the same semiconductor substrate.

12. The image projection device according to claim 1, wherein, The light source further includes a driving circuit for driving the first laser element, the second laser element, and the third laser element, and the driving circuit is arranged on the opposite side of the emission direction of each of the first laser element, the second laser element, and the third laser element.

13. The image projection device according to claim 1, wherein, The light source includes: a driving circuit for driving the first laser element, the second laser element, and the third laser element, and the driving circuit is arranged on the opposite side of the emission direction of each of the first laser element, the second laser element, and the third laser element; a first heat sink arranged to be in contact with the surface opposite to the surface of the semiconductor substrate of the driving circuit on which the first laser element is arranged; a second heat sink arranged to be in contact with the surface on the emission side of the semiconductor substrate of the second laser element; and a third heat sink arranged to be in contact with the surface on the emission side of the semiconductor substrate of the third laser element.

14. The image projection device according to claim 13, wherein, The second heat sink and the third heat sink include holes for emitting the laser beam.

15. The image projection device according to claim 1, wherein, The light source further includes a driving circuit for driving the first laser element, the second laser element, and the third laser element; and the semiconductor substrate is arranged on the driving circuit; the first laser element is arranged on the driving circuit; the second laser element is arranged on the first laser element; and the third laser element is arranged on the second laser element.

16. The image projection device according to claim 1, wherein, The light source includes: a plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; and a driving circuit for driving the plurality of the first laser elements, the plurality of the second laser elements, and the plurality of the third laser elements; wherein, the plurality of the first laser elements are arranged in one direction on the driving circuit, the plurality of the second laser elements are arranged in one direction on the driving circuit, and the plurality of the third laser elements are arranged in one direction on the driving circuit.

17. The image projection apparatus according to claim 10, wherein, The light source includes: a first laser element group including a plurality of the first laser elements; a second laser element group including a plurality of the second laser element groups; and a third laser element group including a plurality of the third laser element groups, wherein, the emitter size is less than or equal to 90 μm, and the emitter size is the distance between the centers of the light emitting portions of the two laser elements that are farthest apart in each laser element group of the first laser element group, the second laser element group, and the third laser element group.

18. The image projection device according to claim 10, wherein, The first light source includes: a first laser element group including a plurality of the first laser elements; a second laser element group including a plurality of the second laser element groups; and a third laser element group including a plurality of the third laser element groups, wherein, the emitter size is less than or equal to 30 μm, and the emitter size is the distance between the centers of the light emitting portions of the two laser elements that are farthest apart in each laser element group of the first laser element group, the second laser element group, and the third laser element group.

19. The image projection device according to claim 10, wherein, The light source includes: a first laser element group including a plurality of the first laser elements; a second laser element group including a plurality of the second laser element groups; and a third laser element group including a plurality of the third laser element groups, wherein the emitter size is less than or equal to 5 μm, and the emitter size is the distance between the centers of the light-emitting portions of the two laser elements that are farthest apart in each of the first laser element group, the second laser element group, and the third laser element group.

20. The image projection apparatus according to claim 1, wherein, The light source further includes a multiplexing optical system for allowing the laser beams emitted from each of the at least one first laser element, the at least one second laser element, and the at least one third laser element to be incident thereon and multiplexing the incident laser beams.

21. The image projection device according to claim 20, wherein, The multiplexing optical system includes: a first reflection optical system arranged to reflect the laser beam emitted from the first laser element toward the scanning device side; a second reflection optical system arranged to reflect the laser beam emitted from the second laser element toward the scanning device side; and a third reflection optical system arranged to reflect the laser beam emitted from the third laser element toward the scanning device side; wherein the first reflection optical system, the second reflection optical system, and the third reflection optical system are arranged such that the laser beams reflected by each of the first reflection optical system, the second reflection optical system, and the third reflection optical system are multiplexed on the same optical axis.

22. The image projection apparatus according to claim 20, wherein, The multiplexing optical system includes: a first reflector for reflecting the laser beam emitted from the first laser element; a second reflector for reflecting the laser beam emitted from the second laser element; and a third reflector for reflecting the laser beam emitted from the third laser element; wherein the multiplexing optical system multiplexes the laser beams reflected by each of the first reflector, the second reflector, and the third reflector on the same optical axis.

23. The image projection device according to claim 20, wherein, The multiplexing optical system is an orthogonal prism.

24. The image projection device according to claim 20, wherein, The light source includes: a first collimating lens arranged between the first laser element and the multiplexing optical system for collimating the laser beam emitted from the first laser element; a second collimating lens arranged between the second laser element and the multiplexing optical system for collimating the laser beam emitted from the second laser element; and a third collimating lens arranged between the third laser element and the multiplexing optical system for collimating the laser beam emitted from the third laser element; wherein the first collimating lens, the second collimating lens, and the third collimating lens collimate the laser beams into the same beam diameter.

25. The image projection device according to claim 20, wherein, The light source includes: a plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; a first collimating lens arranged between the first laser element and the multiplexing optical system for collimating the laser beam emitted from the first laser element; a second collimating lens arranged between the second laser element and the multiplexing optical system for collimating the laser beam emitted from the second laser element; and A third collimating lens, disposed between the third laser element and the multiplexing optical system, for collimating the laser beam emitted from the third laser element.

26. The image projection device according to claim 24, wherein, The first collimating lens, the second collimating lens, and the third collimating lens are diffractive lenses.

27. The image projection device according to claim 24, wherein, The first collimating lens, the second collimating lens, and the third collimating lens are metasurfaces.

28. The image projection device according to claim 27, wherein, The metasurface is arranged to be in contact with the emission surface of each of the first laser element, the second laser element, and the third laser element.

29. The image projection device according to claim 20, further comprising: A plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; A first beam deflector, disposed between the plurality of first laser elements and the multiplexing optical system, for deflecting the optical axis of the laser beam emitted from one of the first laser elements; A second beam deflector, disposed between the plurality of second laser elements and the multiplexing optical system, for deflecting the optical axis of the laser beam emitted from one of the second laser elements; And A third beam deflector, disposed between the plurality of third laser elements and the multiplexing optical system, for deflecting the optical axis of the laser beam emitted from one of the third laser elements.

30. The image projection device according to claim 20, further comprising: A plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; A plurality of first beam deflectors, respectively disposed between each of the first laser elements among the plurality of first laser elements and the multiplexing optical system, for deflecting the optical axis of each laser beam emitted from the plurality of first laser elements; A plurality of second beam deflectors, respectively disposed between each of the second laser elements among the plurality of second laser elements and the multiplexing optical system, for deflecting the optical axis of each laser beam emitted from the plurality of second laser elements; And A plurality of third beam deflectors, respectively disposed between each of the third laser elements among the plurality of third laser elements and the multiplexing optical system, for deflecting the optical axis of each laser beam emitted from the plurality of third laser elements.

31. The image projection device according to claim 1, wherein, The light source includes a waveguide type optical multiplexer, which is used to make the laser beams emitted from each of the first laser element, the second laser element, and the third laser element incident on the waveguide and multiplex the incident laser beams.

32. The image projection device according to claim 31, wherein, The light source includes: A plurality of the waveguide type optical multiplexers; A first group of waveguide type optical multiplexers, for multiplexing the laser beams emitted from the first laser element, the second laser element, and the third laser element of the first group and incident on the waveguide, and emitting a first multiplexed beam; and A second group of waveguide type optical multiplexers, for multiplexing the laser beams emitted from the first laser element, the second laser element, and the third laser element of the second group and incident on the waveguide, and emitting a second multiplexed beam; Wherein, the first group of waveguide type optical multiplexers and the second group of waveguide type optical multiplexers are arranged such that the emission positions of the first multiplexed beam and the second multiplexed beam are close to each other.

33. The image projection apparatus according to claim 32, wherein, The emitter size is less than or equal to 90 μm, and the emitter size is the distance between the center of the emission port of the first group of waveguide-type optical multiplexers and the center of the emission port of the second group of waveguide-type optical multiplexers.

34. The image projection device according to claim 32, wherein, The emitter size is less than or equal to 30 μm, and the emitter size is the distance between the center of the emission port of the first group of waveguide-type optical multiplexers and the center of the emission port of the second group of waveguide-type optical multiplexers.

35. The image projection apparatus according to claim 32, wherein, The emitter size is less than or equal to 5 μm, and the emitter size is the distance between the center of the emission port of the first group of waveguide-type optical multiplexers and the center of the emission port of the second group of waveguide-type optical multiplexers.

36. The image projection device according to claim 31, further comprising: A beam deflector for deflecting the optical axis of the first multiplexed light beam emitted from the first group of waveguide-type optical multiplexers or deflecting the optical axis of the second multiplexed light beam emitted from the second group of waveguide-type optical multiplexers.

37. The image projection device according to claim 1 further comprises: A light source controller for controlling the laser beam emitted from the light source.

38. The image projection device according to claim 37, wherein, Based on the line-of-sight direction detected by the line-of-sight direction detector, the light source controller controls the light source to control the resolution of the image projected onto the user's retina.

39. The image projection device according to claim 37, wherein, The light source controller controls the light source such that the image resolution outside a predetermined area of the image projected in the user's line-of-sight direction is lower than the image resolution within the predetermined area.

40. The image projection device according to claim 37, further comprising: A plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; Wherein, according to the number of the plurality of first laser elements, the number of the plurality of second laser elements, and the number of the plurality of third laser elements, the light source controller controls the light source such that the modulation frequency of each of the plurality of first laser elements, the plurality of second laser elements, and the plurality of third laser elements is lower than the modulation frequency of each of a first laser element, a second laser element, and a third laser element.

41. The image projection device according to claim 37, further comprising: A plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; Wherein, the light source controller controls the number of gray levels of the linear modulation of each of the plurality of first laser elements, the plurality of second laser elements, and the plurality of third laser elements such that the gray level of the image projected onto the user's retina is greater than or equal to 12 bit and less than or equal to 16 bit.

42. The image projection device according to claim 41, wherein, The light source controller controls the number of gray levels of the linear modulation of each of the plurality of first laser elements, the plurality of second laser elements, and the plurality of third laser elements such that the gray level of the image projected onto the user's retina is greater than or equal to 12 bit and less than or equal to 16 bit, so as to project a high dynamic range (HDR) image onto the user's retina.

43. The image projection device according to claim 37, further comprising: A photodetector for detecting the radiation intensity of the laser beam emitted from the light source; Wherein, the light source controller controls the linear modulation gray level of each of the first laser element, the second laser element, and the third laser element based on the detection result of the photodetector.

44. The image projection device according to claim 37, further comprising: A temperature sensor for detecting the temperature of each of the first laser element, the second laser element, and the third laser element; Among them, the light source controller controls the number of gray levels of linear modulation of each of the first laser element, the second laser element, and the third laser element based on the detection result of the temperature sensor.

45. The image projection device according to claim 1, wherein, The projection optical system includes a plurality of mirrors; Among them, the plurality of mirrors include a tilt mirror module having a tilt mirror, and the tilt mirror reflects the laser beam emitted from the light source toward the retina of the user; and The light source controller projects the laser beam onto the retina of the user by controlling the tilt mirror module based on the line-of-sight direction detected by the line-of-sight direction detector.

46. The image projection device according to claim 45, wherein, The tilt mirror module further includes: A movable body including the tilt mirror; A gimbal mechanism that supports the movable body to vibrate the tilt mirror; and A magnetic drive mechanism that vibrates the movable body.

47. The image projection device according to claim 46, further comprising: An angular velocity sensor for detecting the angular velocity of the image projection device; Among them, the light source controller controls the magnetic drive mechanism based on the detection result of the angular velocity sensor.

48. The image projection device according to claim 1 further comprises: A plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; Among them, the plurality of first laser elements are arranged in a zigzag pattern, the plurality of second laser elements are arranged in a zigzag pattern, and the plurality of third laser elements are arranged in a zigzag pattern.

49. The image projection device according to claim 1, wherein, The line-of-sight direction detector is an eye-tracking camera.

50. The image projection apparatus according to claim 1, wherein, The scanning device is a microelectromechanical system (MEMS).

51. The image projection device according to claim 1, wherein, The scanning device scans the laser beam emitted from the light source by using a raster scanning method.

52. The image projection device according to claim 1, wherein, The light source includes a plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; Among them, each laser element in the plurality of first laser elements is separated by a predetermined interval, each laser element in the plurality of second laser elements is separated by a predetermined interval, and each laser element in the plurality of third laser elements is separated by a predetermined interval; Among them, the scanning device uses the light source in which each laser element in the plurality of first laser elements, the plurality of second laser elements, and the plurality of third laser elements is separated by the predetermined interval, and scans the laser beam by using a raster scanning method, so as to reduce the resonance frequency in the main scanning direction and project an image onto the retina of the user with a resolution higher than high definition (HD).

53. The image projection device according to claim 1 further comprises: A mask or filter disposed between the light source and the scanning device.

54. The image projection device according to claim 1, wherein, The light source includes a plurality of the first laser elements, a plurality of the second laser elements, and a plurality of the third laser elements; Among them, the scanning device reduces the resonance frequency in the main scanning direction and scans the laser beam according to the number of the plurality of first laser elements, the number of the plurality of second laser elements, and the number of the plurality of third laser elements.

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