Retina projection type image display device

Abstract

A retinal projection type image display device is provided that can display high-resolution images over a wide range and can be made compact. [Solution] A retinal projection image display device that projects an image onto an observer's retina, comprising: a light source; a light deflection unit that deflects light emitted from the light source; a light scanning unit that scans the light deflected by the light deflection unit using a deflection surface to form an image; a light guiding unit that guides the light scanned by the light scanning unit to the observer's pupil; a first optical system that suppresses divergence of the transmitted light; and a second optical system that suppresses divergence of the transmitted light; the light deflection unit changes the position at which the image is formed by the light scanning unit by changing the incident position of the light on the deflection surface; the first optical system is located in the optical path between the light source and the light deflection unit, and is also located in the optical path between the light deflection unit and the second optical system; the second optical system is located in the optical path between the first optical system and the light scanning unit, and is also located in the optical path between the light scanning unit and the light guiding unit; the light deflection unit, the light scanning unit, and the pupil are conjugate to each other.

Description

[Technical Field]

[0001] The present invention relates to a retinal projection image display device. [Background technology]

[0002] For example, Patent Document 1 discloses a head-mounted display that forms image light using a scanning mirror, projects the image through an optical waveguide, and corrects aberrations in the projected image light by having the optical waveguide include a spatially modulated grating period. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to provide a retinal projection type image display device that can display a high-resolution image over a wide range and that can be made compact. [Means for solving the problem]

[0004] A retinal projection image display device according to one aspect of the present invention is a retinal projection image display device that projects an image onto an observer's retina, and includes a light source, a light deflection unit that deflects light emitted from the light source, a light scanning unit that scans the light deflected by the light deflection unit using a deflection surface to form the image, a light guiding unit that guides the light scanned by the light scanning unit to the observer's pupil, a first optical system that suppresses divergence of transmitted light, and a second optical system that suppresses divergence of transmitted light, wherein the light deflection unit changes the incident position of light on the deflection surface to change the position at which the image is formed by the light scanning unit, the first optical system is located in the optical path between the light source and the light deflection unit, and is also located in the optical path between the light deflection unit and the second optical system, the second optical system is located in the optical path between the first optical system and the light scanning unit, and is also located in the optical path between the light scanning unit and the light guiding unit, and the light deflection unit, the light scanning unit, and the pupil are conjugate to each other. [Effects of the Invention]

[0005] According to the present invention, it is possible to provide a retinal projection image display device that can display high-resolution images over a wide range and that can be made compact. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic perspective view showing an eyeglass-type support body in which a retinal projection image display device according to a first embodiment is arranged. [Figure 2] 1 is a schematic top view showing a retinal projection image display device according to a first embodiment. [Figure 3] 1 is a diagram showing components of a retinal projection type image display device according to a first embodiment, arranged in the order in which light passes. [Figure 4] 1 is a schematic diagram showing an image displayed by a retinal projection image display device according to a first embodiment. [Figure 5] 1 is a schematic top view showing a light deflection unit included in the retinal projection image display device according to the first embodiment. FIG. [Figure 6] 1 is a schematic top view showing a light scanning unit included in a retinal projection image display device according to a first embodiment. FIG. [Figure 7] 2 is a block diagram showing the hardware configuration of a control unit included in the retinal projection image display device according to the first embodiment. FIG. [Figure 8] 2 is a block diagram showing the functional configuration of a control unit included in the retinal projection image display device according to the first embodiment. FIG. [Figure 9] FIG. 10 is a schematic top view showing a retinal projection image display device according to a second embodiment. [Figure 10] FIG. 10 is a schematic top view showing a first example of a retinal projection image display device according to a third embodiment. [Figure 11] FIG. 10 is a schematic top view showing a second example of a retinal projection image display device according to the third embodiment. [Figure 12] FIG. 10 is a schematic top view showing a first example of a retinal projection image display device according to a fourth embodiment. [Figure 13] FIG. 10 is a schematic top view showing a second example of a retinal projection image display device according to the fourth embodiment. [Figure 14]10 is a schematic top view showing a retinal projection type image display device according to a fifth embodiment. FIG. [Figure 15] FIG. 11 is a block diagram showing the functional configuration of a control unit included in a retinal projection image display device according to a fifth embodiment. [Figure 16] 1 is a schematic top view showing a retinal projection type image display device according to a first embodiment. [Figure 17] FIG. 10 is a schematic top view showing a retinal projection type image display device according to a second embodiment. [Figure 18] FIG. 10 is a schematic top view showing a retinal projection type image display device according to a third embodiment. [Figure 19] FIG. 10 is a schematic top view showing a retinal projection type image display device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] A retinal projection type image display device according to an embodiment of the present invention will be described in detail with reference to the drawings. However, the following embodiments are merely examples of the retinal projection type image display device according to the present invention, and the present invention is not limited to the following.

[0008] Unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc. of components described in the embodiments of the present invention are not intended to limit the scope of the embodiments of the present invention to those specific embodiments, and are merely illustrative examples. The sizes, positional relationships, etc. of components shown in each drawing may be exaggerated for clarity. In the following description, the same names and symbols indicate the same or similar components, and detailed descriptions will be omitted as appropriate. Cross-sectional views may be used to show only the cut surface.

[0009] In the following, for ease of explanation, the arrangement and configuration of each part may be described using either an XYZ Cartesian coordinate system or an αβγ Cartesian coordinate system, in which the three axes are mutually orthogonal.

[0010] In the XYZ Cartesian coordinate system, the direction in which the X axis extends is the "X direction," the direction in which the Y axis extends is the "Y direction," and the direction in which the Z axis extends is the "Z direction." In the αβγ Cartesian coordinate system, the direction in which the α axis extends is the "α direction," the direction in which the β axis extends is the "β direction," and the direction in which the γ axis extends is the "γ direction." However, the above directional expressions merely describe the relationship between relative positions, orientations, directions, etc., and do not necessarily correspond to the relationship during use. Furthermore, these directions are unrelated to the direction of gravity.

[0011] In the drawings shown below, as an example, the normal viewing direction of an observer who wears a retinal projection image display device according to an embodiment of the present invention and observes an image corresponds to the -Z direction. Note that the normal viewing direction refers to the line of sight when the observer is looking straight ahead.

[0012] The term "image" in this specification and claims includes not only still images but also moving images. Moving images can also be called video. In this specification, "parallel" may include an inclination of ±10 degrees or less from parallel. Furthermore, "orthogonal" may include an inclination of ±10 degrees or less from orthogonal.

[0013] [First embodiment] <Configuration of the retinal projection image display device according to the first embodiment> A retinal projection image display device according to the first embodiment will be described with reference to Figs. 1 to 6. Fig. 1 is a schematic perspective view showing a support 100 on which a retinal projection image display device 50 according to the first embodiment is arranged. Fig. 2 is a schematic top view showing the retinal projection image display device 50. Fig. 3 is a diagram in which the components of the retinal projection image display device 50 are arranged in the order in which light passes. Fig. 4 is a schematic view showing an image displayed by the retinal projection image display device 50. Fig. 5 is a schematic top view showing a light deflection unit 2 provided in the retinal projection image display device 50. Fig. 6 is a schematic top view showing a light scanning unit 3 provided in the retinal projection image display device 50.

[0014] In recent years, technologies and products related to virtual reality (VR) and augmented reality (AR) have been attracting attention. AR technology in particular is expected to be applied to consumer and industrial fields as a means of realizing new added value by extending the visual perception of the real world and merging digital information with real space. To promote its widespread use, image display devices such as head-mounted displays that can be used in active and working environments are being developed. Transmissive (see-through) head-mounted displays that display virtual images in front of the eyes via eyepiece optical systems such as partially reflective films and image guide structures are the mainstream, and head-mounted displays that display virtual images in front of the eyes via eyepiece optical systems such as partially reflective films and image guide structures have been introduced to the market.

[0015] For head-mounted displays used in real space, optical quality that blends seamlessly into everyday life is an important factor, but style and design are also crucial. Compared to traditional eyeglass frames, head-mounted displays currently available on the market are noticeably larger and less fashionable, putting off consumers. The pursuit of style is a major challenge in this industry. Head-mounted displays must not only have a striking aesthetic, but also deliver the new added value of digital images with sufficient visual quality to users.

[0016] In light of the above, retinal projection image display devices that project images directly onto the retina are attracting attention. Commonly used image display terminals that display virtual images require focusing on an image drawn at a fixed depth, which limits the depth plane on which objects in real space and images can be simultaneously focused, hindering natural human behavior (tasks). On the other hand, retinal projection methods utilize Maxwellian vision to focus an image on the pupil and then project it onto the retina, resulting in a focus-free characteristic that is independent of the observer's visual acuity or focal depth position. This focus-free characteristic allows images to be clearly viewed regardless of the focus point in the external world.

[0017] 1 and 2, a retinal projection image display device 50 according to this embodiment is an image display device that is disposed on a support 100 and projects an image onto the retina of an observer through the pupil P of the observer wearing the support 100. The retinal projection image display device 50 is a head mounted display (HMD) that is worn on the observer's head via the support 100.

[0018] 1, the support 100 includes two temples 151, two light-transmitting members 152, and two frames 153 that correspond to and support the two light-transmitting members 152. The retinal projection image display device 50 projects an image onto the retina of an observer who wears the retinal projection image display device 50 on their head, and displays the image. The observer can observe the image displayed by the retinal projection image display device 50 with Maxwellian vision.

[0019] In the example shown in FIG. 1 , the retinal projection image display device 50 is disposed inside the temple 151 on the left eye side of the viewer out of the two temples 151. However, the retinal projection image display device 50 may also be disposed inside the temple 151 on the right eye side of the viewer, or may be disposed on the frame 153. The retinal projection image display device 50 is not limited to being disposed inside the temple 151, but may also be disposed on the surface. Furthermore, the retinal projection image display device 50 may be disposed inside or on the surface of the frame 153. Some of the components of the retinal projection image display device 50 may be disposed inside or on the surface of the light-transmitting member 152.

[0020] 1 and 2, the retinal projection image display device 50 projects an image onto the retina of the observer through the pupil P of the observer's left eyeball. However, the retinal projection image display device 50 may also project an image onto the retina of the observer through the pupil P of the observer's right eyeball, or may project an image onto the retina of the observer through the pupils P of both eyes.

[0021] The retinal projection image display device 50 may include a support 100 as part of its configuration. In the example shown in Figures 1 and 2, the support 100 is a glasses-type support. However, the support 100 may have various forms such as a headgear type, a hat type, or a helmet type.

[0022] As shown in FIG. 2, a retinal projection image display device 50 includes a light source 1, a light deflection unit 2 that deflects light L emitted from the light source 1, and a light scanning unit 3 that scans the light L deflected by the light deflection unit 2 using a deflection surface 30 to form an image. The retinal projection image display device 50 also includes a light guide unit 4 that guides the light L scanned by the light scanning unit 3 to the observer's pupil P, a first optical system 5, a second optical system 6, and an optical member 7 that has a partially reflective surface 70. In the example shown in FIG. 2, the retinal projection image display device 50 also includes a control unit 9 that controls the operations of the light source 1, the light deflection unit 2, and the light scanning unit 3. The partially reflective surface 70 reflects or transmits incident light. In FIG. 2, an optical axis 50LC indicated by a two-dot chain line is the optical axis of the optical system including the light source 1, the light deflection unit 2, the light scanning unit 3, and the light guide unit 4.

[0023] The first optical system 5 is located in the optical path between the light source 1 and the light deflection unit 2, and is also located in the optical path between the light deflection unit 2 and the second optical system 6. The second optical system 6 is located in the optical path between the first optical system 5 and the light scanning unit 3, and is also located in the optical path between the light scanning unit 3 and the light guiding unit 4. The optical member 7 is located in the optical path between the first optical system 5 and the second optical system 6.

[0024] The first optical system 5 and the second optical system 6 are members, such as biconvex lenses, that suppress divergence of the transmitted light L or focus the transmitted light L so that the optical scanning unit 3 and the optical deflection unit 2 are in a conjugate relationship. The light guiding unit 4 is a member, such as a biconvex lens, that suppresses divergence of the transmitted light L or focus the transmitted light L so that the retina, the optical scanning unit 3, and the optical deflection unit 2 are in a conjugate relationship.

[0025] In this embodiment, the partially reflective surface 70 reflects or transmits light L from the light source 1, light L from the light deflection unit 2, and light L from the light scanning unit 3. In the example shown in FIG. 2 , the partially reflective surface 70 reflects light L emitted from the light source 1 toward the first optical system 5. The partially reflective surface 70 also transmits light L that has been reflected by the partially reflective surface 70, passed through the first optical system 5, deflected by the optical deflection unit 2, and passed through the first optical system 5. The partially reflective surface 70 also reflects light L that has passed through the partially reflective surface 70, passed through the second optical system 6, scanned by the optical scanning unit 3, and passed through the second optical system 6, toward the light guide unit 4.

[0026] 3, light L emitted from the light source 1 passes through the optical member 7, the first optical system 5, the light deflection unit 2, the first optical system 5, the optical member 7, the second optical system 6, the light scanning unit 3, the second optical system 6, the optical member 7, and the light guiding unit 4 in this order, and then reaches the viewer's pupil P. The light deflection unit 2, the light scanning unit 3, and the pupil P are in a conjugate relationship with each other.

[0027] In Fig. 4, a display range 60 represents a range in which the retinal projection image display device 50 can display an image. The display range 60 shown in Fig. 4 is a range in which an image formed by the optical scanning unit 3 and viewed by an observer wearing the retinal projection image display device 50 on their head can be displayed. In the display range 60, image areas 60-1 to 60-9 represent areas in which the retinal projection image display device 50 can partially display an image. Note that, although the display range 60 includes nine image areas in Fig. 4, the number of image areas included in the display range 60 may be any number equal to or greater than two.

[0028] The retinal projection image display device 50 changes the position at which light L is incident on the deflection surface 30 using the optical deflection unit 2, thereby changing the position at which an image is formed by the optical scanning unit 3, and selectively displays an image in at least one image area from image areas 60-1 to 60-9. For example, the retinal projection image display device 50 can display an image only in image area 60-1 from image areas 60-1 to 60-9, display an image only in the group of image areas 60-4 to 60-6, or display an image over the entire image areas 60-1 to 60-9.

[0029] For example, in a see-through retinal projection image display device 50, the display range 60 overlaps the viewer's field of view. When an object appears in the viewer's field of view, the retinal projection image display device 50 displays text information corresponding to the object near the object in the viewer's field of view. The text information corresponding to the object is attribute information of the object, etc. For example, when a dog as an object appears in a position overlapping the image area 60-4 in the viewer's field of view, the retinal projection image display device 50 can display text information about the type of dog, characteristics of the type, etc., only in the image area 60-4.

[0030] Here, for example, if an image is to be displayed over a wide range across the entire display range 60 using only one optical scanning unit without using any optical deflection unit, it is necessary to widen the scanning width of the light by the optical scanning unit to match the display range 60. If the scanning width of the light is widened, the driving amount of the scanning mechanism provided in the optical scanning unit increases, making the mechanical operation of the scanning mechanism unstable, or the scanning pitch and the like fluctuate depending on the scanning angle, which may result in a decrease in the quality of the displayed image and make it impossible to display a high-resolution image.

[0031] The retinal projection image display device 50 uses the optical deflection unit 2 to change the incident position of light L on the deflection surface 30, thereby changing the position at which the image is formed by the optical scanning unit 3. The optical scanning unit 3 scans light within the width of one of the image areas 60-1 to 60-9 in FIG. 4, thereby narrowing the scanning width of the light by the optical scanning unit 3. Furthermore, by using the optical deflection unit 2 to change the image formation position by the optical scanning unit 3, an image can be displayed over a wide range across the entire display area 60. This allows the retinal projection image display device 50 to display an image over a wide range across the entire display area 60 while narrowing the scanning width of the light. The narrow scanning width of the light suppresses instability in the mechanical operation of the scanning mechanism of the optical scanning unit 3 and fluctuations in the scanning pitch depending on the scanning angle. As a result, the retinal projection image display device 50 suppresses degradation in the quality of the displayed image and can display high-resolution images over a wide range.

[0032] When the retinal projection image display device 50 simultaneously displays images in two or more image areas, the optical scanning unit 3 partially forms an image in one image area, and then the optical deflection unit 2 changes the position at which the partial image is formed by the optical scanning unit 3, repeating this operation the same number of times as the number of image areas. It is preferable that the retinal projection image display device 50 displays images in two or more image areas within a predetermined frame period.

[0033] On the other hand, when the incident position of the light L on the deflection surface 30 of the light scanning unit 3 is changed by the light deflection unit 2, if the light L from the light deflection unit 2 is made to directly enter the deflection surface 30 of the light scanning unit 3, a deflection surface 30 with a large area is required, which may increase the size of the light scanning unit 3. If the light scanning unit 3 is made larger, the retinal projection image display device 50 also increases in size. Furthermore, if there are few overlapping light paths (in other words, common light paths) in the light path from the light source 1 to the light deflection unit 2, the light path from the light deflection unit 2 to the light scanning unit 3, and the light path from the light scanning unit 3 to the viewer's pupil P, the overall light path becomes longer, which may increase the size of the retinal projection image display device 50.

[0034] In this embodiment, the retinal projection image display device 50 has a first optical system 5 and a second optical system 6, and the light deflection unit 2, the light scanning unit 3, and the pupil P are conjugate with one another. This reduces the spread of the light L incident on the deflection surface 30 compared to when the light L from the light deflection unit 2 is directly incident on the deflection surface 30 of the light scanning unit 3. Since the spread of the light L incident on the deflection surface 30 is reduced, the area of ​​the deflection surface 30 can be reduced, and the light scanning unit 3 and the retinal projection image display device 50 can be made smaller.

[0035] Moreover, in this embodiment, the retinal projection image display device 50 has an optical member 7, and light L is incident on a partially reflective surface 70 of the optical member 7 from each of the light source 1, the light deflection unit 2, and the light scanning unit 3. As the light L from each of the light source 1, the light deflection unit 2, and the light scanning unit 3 travels via the partially reflective surface 70, there are many overlapping optical paths in the optical path from the light source 1 to the light deflection unit 2, the optical path from the light deflection unit 2 to the light scanning unit 3, and the optical path from the light scanning unit 3 to the viewer's pupil P. As the overlapping optical paths increase, the apparent overall optical path becomes shorter, and the retinal projection image display device 50 can be made smaller.

[0036] The overall optical path in the retinal projection image display device 50 is an optical path that includes the optical path from the light source 1 to the optical deflection unit 2, the optical path from the optical deflection unit 2 to the optical scanning unit 3, and the optical path from the optical scanning unit 3 to the observer's pupil P. The apparent overall optical path means an overall optical path that is shorter than the length of the optical path obtained by simply adding together the optical path from the light source 1 to the optical deflection unit 2, the optical path from the optical deflection unit 2 to the optical scanning unit 3, and the optical path from the optical scanning unit 3 to the observer's pupil P due to a portion of each optical path overlapping.

[0037] 2, the optical path from the light source 1 to the optical deflection unit 2 and the optical path from the optical deflection unit 2 to the optical scanning unit 3 overlap with the optical path from the optical deflection unit 2 to the optical member 7. Due to this overlap, the length of the optical path from the light source 1 to the optical scanning unit 3 is shorter than the length of the optical path obtained by simply connecting the optical path from the light source 1 to the optical deflection unit 2 and the optical path from the optical deflection unit 2 to the optical scanning unit 3.

[0038] As described above, this embodiment can provide a retinal projection image display device 50 that can display high-resolution images over a wide range and can be made compact. Whether the partially reflective surface 70 reflects or transmits the light L from the light source 1, the light L from the light deflection unit 2, and the light scanning unit 3 is not limited to the example shown in Fig. 2, and can be changed as appropriate depending on the specifications of the retinal projection image display device 50, etc.

[0039] The positional relationship between the optical scanning unit 3 and the optical deflection unit 2 may be reversed. In other words, the retinal projection image display device 50 may change the image formation position after forming an image. In this case, too, it is possible to display a high-resolution image and obtain the effect of making the retinal projection image display device 50 more compact.

[0040] As shown in FIG. 2 , in this embodiment, the first optical system 5 forms a first intermediate image 10a, which is an image of the light source 1, and the second optical system 6 forms a second intermediate image 10b, which is an image of the first intermediate image 10a. Note that the intermediate image in this embodiment refers to an image formed temporarily between the light source and the retina. In the example shown in FIG. 2 , the first optical system 5 forms the first intermediate image 10a by transmitting light L from the light source 1 and light L from the optical deflection unit 2. The second optical system 6 forms the second intermediate image 10b by transmitting light L from the first intermediate image 10a and light L from the optical scanning unit 3. The first intermediate image 10a and the second intermediate image 10b overlap in the optical path between the second optical system 6 and the optical member 7. Note that in FIG. 2 , the first intermediate image 10a and the second intermediate image 10b are indicated by the same reference numerals to indicate that the first intermediate image 10a and the second intermediate image 10b overlap.

[0041] The first optical system 5 forms the first intermediate image 10a, and the second optical system 6 forms the second intermediate image 10b, so that the optical deflection unit 2, the optical scanning unit 3, and the pupil P are conjugate with each other. This allows the area of ​​the deflection surface 30 to be reduced, resulting in a smaller optical scanning unit 3 and a smaller retinal projection image display device 50. Furthermore, the overlap between the first intermediate image 10a and the second intermediate image 10b increases the overlap between the optical path from the optical deflection unit 2 to the optical scanning unit 3 and the optical path from the optical scanning unit 3 to the viewer's pupil P. This further reduces the size of the retinal projection image display device 50. Furthermore, the overlap between the first intermediate image 10a and the second intermediate image 10b in the optical path between the second optical system 6 and the optical member 7 shortens the overall optical path compared to, for example, when the first intermediate image 10a and the second intermediate image 10b overlap between the optical scanning unit 3 and the second optical system 6. This further reduces the size of the retinal projection image display device 50.

[0042] Each component of the retinal projection image display device 50 will be described in detail below.

[0043] (Light source 1) The light source 1 is a semiconductor laser that emits laser beams of a single wavelength or multiple wavelengths. For example, the light source 1 is configured to include a red semiconductor laser, a green semiconductor laser, and a blue semiconductor laser. The light source 1 emits light L, which is time-modulated laser light, in response to a drive signal from a control unit provided in the retinal projection image display device 50. Since the light source 1 includes a red semiconductor laser, a green semiconductor laser, and a blue semiconductor laser, the retinal projection image display device 50 can display color images. However, the retinal projection image display device 50 can also display only monochrome images. When displaying only monochrome images, the light source 1 may emit light of a single color.

[0044] The light intensity of the light L emitted from the light source 1 is set in advance to an appropriate light intensity that fully considers the safety of the eyes of the observer U. However, the retinal projection image display device 50 may be equipped with an optical element that reduces the light intensity of the light L, as necessary. Furthermore, the retinal projection image display device 50 may have a light-receiving element such as a photodiode that receives the light L emitted by the light source 1 and outputs a signal corresponding to the light intensity of the light L, and may control the light intensity of the light L based on the output signal of the light-receiving element so as to ensure the safety of the eyes of the observer U. Note that the light intensity that can ensure the safety of the eyes of the observer U refers to a light intensity that is below Class 1 specified in IEC (International Electrotechnical Commission) 60825-1, an international standard regarding the safety of laser light. Furthermore, the light source 1 is not limited to a semiconductor laser, and may be a solid-state laser or a gas laser.

[0045] The retinal projection image display device 50 can change the current or voltage applied to the light source 1 to change the light intensity of the light L emitted from the light source 1. This allows the retinal projection image display device 50 to adjust the brightness of the image to be displayed according to the brightness of the surrounding environment in which the retinal projection image display device 50 is used.

[0046] (Light deflector 2) The optical deflection unit 2 shown in FIG. 5 is a MEMS mirror capable of deflecting light in two axes. The optical deflection unit 2 has a reflective surface 14 on a movable portion 101 connected to a support substrate 102. The optical deflection unit 2 can selectively switch the reflection direction of light by driving the movable portion 101 to change the orientation of the reflective surface 14. The optical deflection unit 2 is rotatable around an A-axis along the β-axis, and its orientation can be controlled at any position within its movable range by a drive voltage signal. The optical deflection unit 2 is also rotatable around a B-axis along the α-axis, and its orientation can be controlled at any position within its movable range by a drive voltage signal. In other words, the optical deflection unit 2 can reflect light L incident from the first optical system 5 to any position within the αβ plane within its movable range. The optical deflection unit 2 is also disposed in the optical path between the light source 1 and the optical scanning unit 3.

[0047] The optical deflection unit 2 has a movable part 101 that reflects incident light L, and a support substrate 102 that supports a first member 110, a second member 120, a third member 130, and a fourth member 140, the first member 110 having piezoelectric driving parts (113a, 113b, 113c, 113d) connected to the movable part 101 and driving the movable part 101. The optical deflection unit 2 also has a connection portion 102a that connects the first member 110 and the movable portion 101, a connection portion 102b that connects the second member 120 and the movable portion 101, a connection portion 102c that connects the third member 130 and the movable portion 101, a connection portion 102d that connects the fourth member 140 and the movable portion 101, and electrode connection portions 150a to 150h that electrically connect the piezoelectric drive units (113a, 113b, 113c, 113d) to the control device.

[0048] 5, each component is integrally formed by forming a single SOI substrate by etching or the like, and then forming the reflecting surface 14, piezoelectric driving units (113a, 113b, 113c, 113d), electrode connecting units 150a-150h, etc. on the formed substrate. Note that the formation of each component may be performed after or during the formation of the SOI substrate.

[0049] An SOI substrate is a substrate in which a silicon oxide layer is provided on a silicon support layer made of single-crystal silicon (Si), and a silicon active layer made of single-crystal silicon is further provided on the silicon oxide layer. Because the silicon active layer is thinner in the γ direction than in the α or β directions, a member made only of the silicon active layer functions as an elastic part. The SOI substrate does not necessarily have to be flat, and may have curvature, etc. Furthermore, the member used to form the MEMS mirror is not limited to an SOI substrate, as long as it can be integrally formed by etching or other processes and can be made partially elastic.

[0050] The reflecting surface 14 is made of a metal thin film containing, for example, aluminum, gold, silver, etc. The movable portion 101 may also have a rib formed on the -γ side surface of the movable portion base 103 for reinforcing the movable portion. The rib is made of, for example, a silicon support layer 124 and a silicon oxide layer 125, and can suppress distortion of the reflecting surface 14 caused by movement.

[0051] The shape or configuration of the first member 110, the second member 120, the third member 130, and the fourth member 140 may be, for example, a meander structure or a cantilever structure. Furthermore, some kind of sensor may be formed in the first member 110, the second member 120, the third member 130, and the fourth member 140, in addition to the piezoelectric driving units (113a, 113b, 113c, 113d). The sensor may be, for example, a displacement detection sensor (piezoelectric type, strain resistance type, etc.) that outputs a signal in response to deformation of the member, or a temperature sensor.

[0052] The detailed shape of the connection parts (102a, 102b, 102c, 102d) that connect the members and the movable part 101 is not limited to the configuration shown in FIG. 5. Furthermore, it is desirable that the angle formed by the lines formed by the connection parts (102a, 102b, 102c, 102d) and the center of the movable part 101 is approximately 90 degrees in a plan view. However, this is not limited to this. Furthermore, the piezoelectric drive parts (113a, 113b, 113c, 113d) may have functions other than drive. For example, the drive parts may have the functions of displacement detection, heating, or electrical wiring.

[0053] The piezoelectric actuators (113a, 113b, 113c, 113d) are driven by a piezoelectric drive system. However, the drive system of the piezoelectric actuators (113a, 113b, 113c, 113d) is not limited to the piezoelectric drive system. For example, the drive system may be an electromagnetic drive system that uses an electromagnetic field to deform the support, an electrostatic drive system in which comb-shaped electrodes are formed on the support, or a thermoelectric drive system that utilizes the difference in thermal expansion between different materials. Coils or a magnet array may be formed on the support substrate 102. Among these, the piezoelectric drive system is preferable from the viewpoint of efficiently arranging the piezoelectric actuators (113a, 113b, 113c, 113d) and preventing the overall size of the optical deflection unit 2 from increasing. For example, in the electrostatic drive system, comb-shaped electrodes are arranged around the outer periphery of the actuators, which tends to increase the overall size of the movable mirror. In addition, in the electromagnetic drive system, it is difficult to layout the wiring for each of the multiple actuators and to arrange magnets so that a magnetic field is applied to each, which tends to increase the overall size of the movable mirror. The piezoelectric driving units (113a, 113b, 113c, 113d) are not limited to being arranged on only one surface (the +γ side surface) of the silicon active layer 126, which is the elastic portion, but may be arranged on another surface (for example, the -γ side surface) of the elastic portion, or may be arranged on both one surface and the other surface of the elastic portion.

[0054] An insulating layer made of a silicon oxide film may be disposed on at least one of the +γ side surfaces of the upper electrodes of the piezoelectric drive units (113a, 113b, 113c, 113d) and the +γ side surface of the support substrate 102. In this case, electrode wiring may be disposed on the insulating layer, and the insulating layer may be partially removed or not disposed at only the connection spots where the upper or lower electrodes are connected to the electrode wiring to form openings. This increases the degree of freedom in designing the piezoelectric drive units (113a, 113b, 113c, 113d) and the electrode wiring, and further prevents short circuits due to contact between electrodes.

[0055] The silicon oxide film in the optical deflection unit 2 also functions as an anti-reflection material. When a positive or negative voltage is applied to the piezoelectric portion of each of the piezoelectric drive units (113a, 113b, 113c, 113d) in the polarization direction, deformation (e.g., expansion and contraction) occurs in proportion to the potential of the applied voltage, thereby exhibiting the so-called inverse piezoelectric effect. The deformation of the piezoelectric portion causes bending deformation of the piezoelectric drive units (113a, 113b, 113c, 113d), and a driving force about the rotation axis acts on the movable unit 101 via the connection units (102a, 102b, 102c, 102d), causing the movable unit 101 to move about the rotation axis of the A axis parallel to the β axis or the B axis parallel to the α axis.

[0056] The first member 110 is positioned at approximately 45 degrees with respect to each of the A-axis and the B-axis. In other words, the rotation of the movable part 101 caused by the oscillation of the first member 110, the second member 120, the third member 130, and the fourth member 140 all has vectors of both the A-axis and the B-axis. For example, when a voltage is applied to the piezoelectric actuators (113a, 113b) but not to the piezoelectric actuators (113c, 113d), the movable part 101 tilts around the B-axis as the rotation axis. Similarly, when a voltage is applied to the piezoelectric actuators (113a, 113d) but not to the piezoelectric actuators (113c, 113d), the movable part 101 tilts around the A-axis as the rotation center. In particular, when a drive frequency that does not match the resonant frequency inherent to the structure is used, the rotation direction of the movable part 101 can be arbitrarily controlled by the drive signal. That is, by controlling the independent driving of each of the piezoelectric driving units (113a, 113b, 113c, 113d) or the combined driving, the movable unit 101 can be swung in a desired direction, thereby enabling vector scanning.

[0057] The reference voltage of the piezoelectric driving units (113a, 113b, 113c, 113d) may be 0V or any voltage within the maximum amplitude of the applicable voltage. It may be different between the piezoelectric driving units (113a, 113b, 113c, 113d). The signal waveform of the applied voltage may be a periodic waveform such as a sine wave, a square wave, or a sawtooth wave, or may be a more complex periodic waveform. The piezoelectric driving units (113a, 113b, 113c, 113d) may be DC driven.

[0058] The light deflection unit 2 is not limited to a MEMS mirror capable of deflecting light in two axial directions, and may be configured using two uniaxial MEMS mirrors. However, using a vector scan MEMS mirror is preferable because it allows the retinal projection image display device 50 to be made smaller and lighter. Alternatively, it may be configured using one uniaxial MEMS mirror.

[0059] (Optical scanning unit 3) The optical scanning unit 3 shown in FIG. 6 includes a support substrate 91, a movable unit 92, a serpentine beam unit 93, a serpentine beam unit 94, and an electrode connection unit 95.

[0060] The optical scanning unit 3 has a deflection surface 30 on a movable part 92 connected to a support substrate 91. The optical scanning unit 3 swings the movable part 92 to change the angle of the deflection surface 30, thereby scanning the reflected light of light L incident on the deflection surface 30. The optical scanning unit 3 scans the reflected light of light L, thereby drawing pixels successively in time with the scanning light Ls.

[0061] The serpentine beam portion 93 has a plurality of folded portions and is formed in a serpentine shape, with one end connected to the support substrate 91 and the other end connected to the movable portion 92. The serpentine beam portion 93 includes a beam portion 93a including three beams and a beam portion 93b including three beams. The beams of the beam portion 93a and the beams of the beam portion 93b are formed alternately. Each of the beams included in the beam portion 93a and the beam portion 93b is independently equipped with a piezoelectric element. The number of beams included in the beam portion 93a is not limited to three and may be any number.

[0062] The serpentine beam portion 94 has a plurality of folded portions and is formed in a serpentine shape, with one end connected to the support substrate 91 and the other end connected to the movable portion 92. The serpentine beam portion 94 includes a beam portion 94a including three beams and a beam portion 94b including three beams. The beams of the beam portion 94a and the beams of the beam portion 94b are formed alternately. Each of the beams included in the beam portion 94a and the beam portion 94b is independently equipped with a piezoelectric element. The number of beams included in the beam portion 94b is not limited to three and may be any number.

[0063] The piezoelectric elements included in each of beams 93a, 93b, 94a, and 94b are provided as piezoelectric layers in, for example, a portion of each layer of a multi-layered beam. Hereinafter, the piezoelectric elements included in beams 93a and 94a may be referred to as piezoelectric elements 95a, and the piezoelectric elements included in beams 93b and 94b may be referred to as piezoelectric elements 95b. When voltage signals of opposite phases are applied to piezoelectric elements 95a and 95b to warp the serpentine beam 94, adjacent beams bend in different directions. This warping accumulates, generating a rotational force that causes deflection surface 30 to reciprocate around axis A, which is parallel to the β direction.

[0064] The movable portion 92 is formed so as to be sandwiched in the β direction between the serpentine beam portion 93 and the serpentine beam portion 94. The movable portion 92 includes a deflection surface 30, a torsion bar 92b, a piezoelectric member 92c, and a support portion 92d.

[0065] The deflection surface 30 is formed, for example, by depositing a metal thin film containing aluminum, gold, silver, etc. on a base material. One end of the torsion bar 92b is connected to the deflection surface 30, and the torsion bar 92b extends in the positive and negative α directions to rotatably support the deflection surface 30.

[0066] One end of the piezoelectric element 92c is connected to the torsion bar 92b, and the other end is connected to the support portion 92d. When a voltage is applied to the piezoelectric element 92c, the piezoelectric element 92c is bent and deformed, causing a twist in the torsion bar 92b. The twist in the torsion bar 92b acts as a rotational force, causing the deflection surface 30 to rotate around the B axis, which is parallel to the α direction.

[0067] By rotating the deflecting surface 30 about the A axis, the light L incident on the deflecting surface 30 is scanned in the α direction. By rotating the deflecting surface 30 about the B axis, the light L incident on the deflecting surface 30 is scanned in the β direction.

[0068] The support portion 92d is formed to surround the deflection surface 30, the torsion bar 92b, and the piezoelectric member 92c. The support portion 92d is connected to the piezoelectric member 92c and supports the piezoelectric member 92c. The support portion 92d indirectly supports the deflection surface 30 and the torsion bar 92b connected to the piezoelectric member 92c.

[0069] Support substrate 91 is formed to surround movable portion 92, serpentine beam portion 93, and serpentine beam portion 94. Support substrate 91 is connected to and supports serpentine beam portion 93 and serpentine beam portion 94. Support substrate 91 indirectly supports movable portion 92, which is connected to serpentine beam portion 93 and serpentine beam portion 94.

[0070] The optical scanning unit 3 is a MEMS mirror formed by micromachining silicon or glass, for example, using micromachining technology. Micromachining technology allows highly accurate, movable, tiny mirrors to be formed on a substrate, integrated with drive units such as serpentine beams. Specifically, for example, a single SOI (Silicon On Insulator) substrate is shaped by etching or other processes. A reflective mirror, serpentine beams, piezoelectric members, electrode connections, and other components are integrally formed on the shaped substrate, thereby forming the MEMS mirror. The reflective mirror and other components may be formed after or during the shaping of the SOI substrate.

[0071] An SOI substrate is a substrate in which a silicon oxide layer is provided on a silicon support layer made of single-crystal silicon (Si), and a silicon active layer made of single-crystal silicon is further provided on the silicon oxide layer. Because the silicon active layer is thinner in the γ direction than in the α or β directions, a member made only of the silicon active layer functions as an elastic part. The SOI substrate does not necessarily have to be flat, and may have curvature, etc. Furthermore, the member used to form the MEMS mirror is not limited to an SOI substrate, as long as it can be integrally formed by etching or other processes and can be made partially elastic.

[0072] The optical scanning unit 3 is not limited to a configuration using one biaxial MEMS mirror as long as it can scan light in two axial directions. For example, the optical scanning unit 3 may be configured to use two uniaxial MEMS mirrors. Furthermore, optical elements capable of scanning light, such as polygon mirrors and galvanometer mirrors, may be used, or a combination of these may be used. However, using a MEMS mirror is preferable because it allows the retinal projection image display device 50 to be made smaller and lighter. In particular, a configuration using only one MEMS mirror is even more preferable because it allows the retinal projection image display device 50 to be made smaller and lighter. The driving method for the MEMS mirror may be any of electrostatic, piezoelectric, electromagnetic, etc.

[0073] (Light guiding section 4, first optical system 5, second optical system 6) The light guiding unit 4, the first optical system 5, and the second optical system 6 are each, for example, a lens. The lenses of the light guiding unit 4, the first optical system 5, and the second optical system 6 are made of, for example, a glass material having a transmittance of 60% or more for the light L emitted from the light source 1. The number of lenses of the light guiding unit 4, the first optical system 5, and the second optical system 6 is not limited to one, but may be multiple. The light guiding unit 4, the first optical system 5, and the second optical system 6 may include various types of lenses, such as a spherical lens, an aspherical lens, a Fresnel lens, or a diffractive lens. Furthermore, the light guiding unit 4, the first optical system 5, and the second optical system 6 may include optical elements other than lenses, such as a mirror. From the viewpoint of reducing flare light and ghost light, it is preferable that a reflection-reducing film that reduces reflection of the light L be applied to surfaces of the light guiding unit 4, the first optical system 5, and the second optical system 6 other than the surfaces that are intended to reflect light.

[0074] (Optical component 7) The optical member 7 is, for example, a cube-shaped beam splitter. However, the optical member 7 may also be a half mirror or the like. The optical member 7 is made of, for example, a glass material or the like having a transmittance of 60% or more for the light L emitted from the light source 1. From the viewpoint of reducing flare light and ghost light, it is preferable that a reflection-reducing film that reduces reflection of the light L is applied to the surfaces of the optical member 7 other than the partially reflecting surface 70.

[0075] (Control unit 9) The control unit 9 is connected to each of the light source 1, the light deflection unit 2, and the light scanning unit 3 so as to be able to communicate with each other via wire or wirelessly. The control unit 9 receives image data that is the basis of the entire image to be formed, and controls the emission of light L by the light source 1 based on the received image data. The control unit 9 also controls the light deflection unit 2 to deflect the light L emitted from the light source 1, and the light scanning unit 3 to scan the light L deflected by the light deflection unit 2 across a deflection surface 30 to form an image.

[0076] (Hardware configuration of control unit 9) 7 is a block diagram showing the hardware configuration of the control unit 9. The control unit 9 has a CPU (Central Processing Unit) 911, a ROM (Read Only Memory) 912, a RAM (Random Access Memory) 913, a light source drive circuit 914, a scan drive circuit 915, and a deflection drive circuit 916. These are electrically connected to each other via a system bus B.

[0077] The CPU 911 is a computing device that reads programs and data from storage devices such as the ROM 912 onto the RAM 913, executes processing, and realizes the overall control and functions of the control unit 9. The ROM 912 is a non-volatile storage device that can retain programs and data even when the power is turned off. The ROM 912 stores processing programs and data that the CPU 911 executes to control each function of the retinal projection image display device 50d. The RAM 913 is a volatile storage device that temporarily stores programs and data.

[0078] The light source drive circuit 914 is an electric circuit that applies a current or voltage to the light source 1 to drive the light source 1. The light source 1 turns on or off the emission of light L and changes the light intensity of the emitted light L according to a drive signal D1 output from the light source drive circuit 914.

[0079] The scan drive circuit 915 is an electric circuit that applies a voltage to drive the optical scanning unit 3. The optical scanning unit 3 changes the angle of the deflection surface 30 provided on the movable unit 92 in response to a drive signal D2 output from the scan drive circuit 915.

[0080] The deflection drive circuit 916 is an electric circuit that applies a voltage to drive the optical deflection unit 2. The optical deflection unit 2 changes the inclination angle of the reflecting surface 14 of the movable unit 101 in response to a drive signal D3 output from the deflection drive circuit 916.

[0081] The external I / F 917 is an interface with an external device, a network, etc. Examples of external devices include higher-level devices such as a PC (Personal Computer), and storage devices such as a USB (Universal Serial Bus) memory, an SD card, a CD, a DVD, a HDD, and an SSD. Examples of networks include a CAN (Controller Area Network) in an automobile, a LAN (Local Area Network), the Internet, etc. The external I / F 917 may have any configuration as long as it enables connection or communication with an external device, and an external I / F 917 may be provided for each external device.

[0082] In the control unit 9, the CPU 911 acquires image data from an external device or a network via the external I / F 917. Note that any configuration is acceptable as long as the CPU 911 can acquire video information, and the image data may be stored in the ROM 912 within the control unit 9, or a new storage device such as an SD card may be provided within the control unit 9, and the image data may be stored in that storage device.

[0083] (Functional configuration of the control unit 9) 8 is a block diagram showing the functional configuration of the control unit 9. The control unit 9 has a light source control unit 902, a scanning control unit 903, and a deflection control unit 904. Note that the control unit 9 may further have a function of correcting distortions, etc., when the image visually recognized by the observer has distortions, etc.

[0084] The functions of the light source control unit 902, the scanning control unit 903, and the deflection control unit 904 can be realized by an external I / F 917 and the CPU 911 executing processes defined in a program stored in a ROM 912. Some of the functions of the light source control unit 902 may be realized by a light source drive circuit 914. Some of the functions of the scanning control unit 903 may be realized by a scan drive circuit 915. Some of the functions of the deflection control unit 904 may be realized by a deflection drive circuit 916. The functions of the light source control unit 902, the scanning control unit 903, and the deflection control unit 904 may be included in a configuration other than the control unit 9. For example, an external device such as a microcomputer or a PC capable of communicating with the control unit 9 may have at least some of the functions of the estimation unit 901, the light source control unit 902, the scanning control unit 903, and the deflection control unit 904.

[0085] Each function of the control unit 9 can also be realized by one or more processing circuits. The processing circuits include an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), a DSP (Digital Signal Processor), an electric circuit, or the like, which can execute each of the above functions. Some of the above functions of the control unit 9 may be realized by an external device, such as a microcomputer or a PC, that is communicably connected to the control unit 9. Furthermore, some of the above functions of the control unit 9 may be realized by distributed processing between the control unit 9 and the external device.

[0086] The light source control unit 902 drives the light source 1. The scanning control unit 903 outputs a drive signal D2 to the optical scanning unit 3 to drive the optical scanning unit 3. The deflection control unit 904 outputs a drive signal D3 to the optical deflection unit 2 to drive the optical deflection unit 2.

[0087] [Second embodiment] Next, a retinal projection type image display device according to a second embodiment will be described. Note that the same names and symbols as those in the already described embodiments indicate the same or similar components or configurations, and detailed descriptions will be omitted as appropriate. This also applies to the following embodiments and examples.

[0088] 9 is a schematic top view showing a retinal projection image display device 50a according to the second embodiment. This embodiment differs from the retinal projection image display device 50 according to the first embodiment in that the partially reflective surface 70 has a higher reflectance for incident S-polarized light than for incident P-polarized light.

[0089] 9, a retinal projection type image display device 50a has a first quarter-wave plate 81 arranged in the optical path between the optical member 7 and the optical deflection unit 2, and a second quarter-wave plate 82 arranged in the optical path between the optical member 7 and the optical scanning unit 3. This optical member 7 is, for example, a polarizing beam splitter (PBS). The partially reflecting surface 70 of the polarizing beam splitter has a higher reflectance for incident S-polarized light than for incident P-polarized light.

[0090] The first quarter-wave plate 81 and the second quarter-wave plate 82 may each be made of an optical crystal or the like having birefringence. However, the first quarter-wave plate 81 and the second quarter-wave plate 82 may also be made of a resin material or the like having birefringence. Furthermore, the first quarter-wave plate 81 and the second quarter-wave plate 82 may also be provided integrally with the optical member 7.

[0091] In the example shown in FIG. 9, S-polarized light L emitted from the light source 1 is incident on the optical member 7. The optical member 7 reflects the incident S-polarized light L toward the first optical system 5. The light L that has passed through the first optical system 5 and been converted into parallel light is incident on the first quarter-wave plate 81. The first quarter-wave plate 81 is disposed so that its optical axis is tilted at approximately 45 degrees with respect to the incident S-polarized light. As a result, the light L that has passed through the first quarter-wave plate 81 is converted into right-handed circularly polarized light. Note that a polarizing plate or a polarizing prism may be disposed between the light source 1 and the optical member 7 to increase the extinction ratio.

[0092] The light L that has passed through the first quarter-wave plate 81 is converted into left-handed circularly polarized light by being reflected by the optical deflection unit 2, and is then converted into P-polarized light by passing through the first quarter-wave plate 81 again. The P-polarized light L that has passed through the first quarter-wave plate 81 passes through the first optical system 5, enters the optical member 7, and passes through the partially reflecting surface 70. Because the partially reflecting surface 70 has a low reflectance for P-polarized light, much of the P-polarized light L that passes through the first optical system 5 and enters the optical member 7 passes through the partially reflecting surface 70 efficiently.

[0093] The P-polarized light L that has passed through the partially reflecting surface 70 passes through the first optical system 5, where it is collimated, and then enters the second quarter-wave plate 82. The second quarter-wave plate 82 is positioned so that its optical axis is tilted at approximately 45 degrees with respect to the incident P-polarized light. The P-polarized light L that has entered the second quarter-wave plate 82 is converted into left-handed circularly polarized light.

[0094] The light L that has passed through the second quarter-wave plate 82 is converted into right-handed circularly polarized light by being reflected by the optical scanning unit 3, and is then converted into S-polarized light by passing through the second quarter-wave plate 82 again. The S-polarized light L that has passed through the second quarter-wave plate 82 passes through the second optical system 6 and enters the optical member 7, where it is reflected by the partially reflecting surface 70. Because the partially reflecting surface 70 has a high reflectivity for S-polarized light, much of the S-polarized light L that passes through the second optical system 6 and enters the optical member 7 is efficiently reflected by the partially reflecting surface 70. The S-polarized light L reflected by the partially reflecting surface 70 passes through the light guiding unit 4 and reaches the pupil P.

[0095] As described above, in this embodiment, the retinal projection image display device 50 has the first quarter-wave plate 81 and the second quarter-wave plate 82, and the optical member 7 is a polarizing beam splitter. This makes the reflectance of the partially reflective surface 70 for S-polarized light higher than the reflectance of the partially reflective surface 70 for P-polarized light. As a result, the light L is efficiently transmitted through the partially reflective surface 70 and is also efficiently reflected by the partially reflective surface 70, thereby increasing the light utilization efficiency. Furthermore, because unnecessary reflected light by the partially reflective surface 70 is reduced, flare light or ghost light resulting from the unnecessary reflected light is reduced.

[0096] The optical member 7 may be an optical element other than a polarizing beam splitter, as long as the reflectance for incident S-polarized light is higher than the reflectance for incident P-polarized light.

[0097] [Third embodiment] 10 is a schematic top view showing a first example of a retinal projection image display device 50a according to the third embodiment. In this embodiment, the partially reflective surface 70 differs from the retinal projection image display device 50 according to the first embodiment in that it includes a first partially reflective surface 70-1 and a second partially reflective surface 70-2.

[0098] 10, the retinal projection image display device 50b has an optical member 7b. The optical member 7b includes a first partially reflective surface 70-1 and a second partially reflective surface 70-2. The first partially reflective surface 70-1 reflects light L emitted from the light source 1 toward the first optical system 5. The first partially reflective surface 70-1 also transmits light L that has been reflected by the first partially reflective surface 70-1, passed through the first optical system 5, deflected by the optical deflection unit 2, and passed through the first optical system 5. The second partially reflective surface 70-2 reflects light L that has passed through the first partially reflective surface 70-1, passed through the second optical system 6, scanned by the optical scanning unit 3, and passed through the second optical system 6 toward the light guide unit 4.

[0099] Optical member 7b can be constructed, for example, by joining prisms 71, 72, and 73. The bonding surface between prisms 71 and 72 corresponds to first partially reflecting surface 70-1. The bonding surface between prisms 72 and 73 corresponds to second partially reflecting surface 70-2. Prisms 71, 72, and 73 are constructed from a material such as glass having a transmittance of 60% or more for light L emitted from light source 1. From the perspective of reducing flare light or ghost light, it is preferable that a reflection-reducing film that reduces reflection of light L be applied to surfaces of optical member 7b other than partially reflecting surface 70.

[0100] In this embodiment, the first partially reflective surface 70-1 and the second partially reflective surface 70-2 are arranged on the optical path from the light source 1 to the retina. This makes it possible to prevent the P-polarized light incident on the first partially reflective surface 70-1 and the second partially reflective surface 70-2 from being converted into ghost light or flare light, compared to when only one partially reflective surface is arranged on the optical path from the light source 1 to the retina.

[0101] 11 is a schematic top view showing a second example of a retinal projection image display device 50b. In the second example, the optical member 7b includes a first optical member 7-1 and a second optical member 7-2, and is different from the first example in that the first optical member 7-1 has a first partially reflective surface 70-1 and the second optical member 7-2 has a second partially reflective surface 70-2. The retinal projection image display device 50b according to the second example also provides the same effects as the retinal projection image display device 50b according to the first example.

[0102] [Fourth embodiment] Next, a retinal projection type image display device according to a fourth embodiment will be described.

[0103] 12 is a schematic top view showing a first example of a retinal projection image display device 50c according to the fourth embodiment. The retinal projection image display device 50c according to the first example of this embodiment differs from the retinal projection image display device 50 according to the first embodiment in that it has a light guide plate 11.

[0104] The light guide plate 11 is a plate-like member that combines light from the light guide section 4, guides the light inside the light guide plate 11, and then emits the light toward the viewer's eyeball E. The light guide plate 11 is made of, for example, a glass material or the like that has a transmittance of 60% or more for the light L emitted from the light source 1.

[0105] The retinal projection image display device 50c according to the first example also provides the same effects as those of the retinal projection image display device 50 according to the first embodiment.

[0106] 13 is a schematic top view showing a second example of a retinal projection image display device 50c according to the fourth embodiment. The retinal projection image display device 50c according to the second example of this embodiment differs from the first example in that it does not have a light guide plate 11 but has a reflective member 12.

[0107] The reflecting member 12 is a member that reflects light from the light guiding unit 4 toward the eye E. The reflecting member 12 includes a member made of, for example, a metal material, a resin material, or a glass material, and a reflecting film provided on the surface of the plate-like member. The reflecting film can be a metal film, a dielectric multilayer film, or the like.

[0108] The retinal projection image display device 50c according to the second example also provides the same effects as the retinal projection image display device 50c according to the first example.

[0109] [Fifth embodiment] Next, a retinal projection type image display device according to the fifth embodiment will be described. Fig. 14 is a schematic top view showing a retinal projection type image display device 50d according to the fifth embodiment.

[0110] The retinal projection image display device 50d of this embodiment differs from the retinal projection image display device 50 of the first embodiment in that it has a detection unit 13 that detects the position of the observer's pupil or cornea, and a control unit 9 that controls the operation of the light deflection unit 2 so that the position of the image formed by the light scanning unit 3 changes depending on the detection result by the detection unit 13.

[0111] (Detection unit 13) 14, the detection unit 13 has a detection light source 131 that emits detection light S1 toward the cornea K of the eyeball E, and a detection light receiving unit 132 that receives reflected light S2 from the eyeball E of the detection light S1 emitted from the detection light source 131. In the example shown in Fig. 14, for ease of explanation, the detection light source 131 and the detection light receiving unit 132 are arranged near the eyeball E, but the arrangement positions of the detection light source 131 and the detection light receiving unit 132 can be selected as appropriate.

[0112] The detection light source 131 can be an array light source having multiple light-emitting elements such as a vertical cavity surface-emitting laser (VCSEL), a laser diode array (LDA), or a light-emitting diode (LED), or a semiconductor laser that emits laser beams of a single or multiple wavelengths.

[0113] The wavelength of the detection light S1 emitted from the detection light source 131 is preferably a wavelength of near-infrared light, which is invisible light, so as not to impede the visibility of the observer whose gaze direction is being detected. However, the wavelength is not limited to invisible light and may be visible light. The detection light source 131 is positioned so that the emitted detection light S1 is incident on the cornea K of the eyeball E.

[0114] The detection light receiving unit 132 is at least one photodiode that outputs a detection signal according to the light intensity of the received reflected light S2. However, the detection light receiving unit 132 may also be a position sensitive detector (PSD), which is a position detecting element, or an imaging element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0115] The surface of the cornea K, which corresponds to the surface of the observer's eyeball E, is a transparent body containing water and generally has a reflectance of approximately 2 to 4%. The detection light S1 incident on the cornea K is reflected by the surface of the cornea K and enters the detection light receiving unit 132.

[0116] (Control unit 9) The control unit 9 differs from the control unit 9 included in the retinal projection image display device 50 according to the first embodiment in that the control unit 9 is connected to the detection unit 13 so as to be able to communicate with the detection unit 13 via wired or wireless communication. The control unit 9 controls the emission of the detection light S1 by the detection light source 131. The control unit 9 also controls the deflection angle of the light L by the light deflection unit 2 based on the light emission timing of each light-emitting unit in the detection light source 131 and the position of the pupil P or cornea K of the viewer detected based on a light reception signal from the detection light-receiving unit 132.

[0117] (Functional configuration of the control unit 9) 15 is a block diagram showing the functional configuration of the control unit 9. The control unit 9 differs from the control unit 9 provided in the retinal projection image display device 50 according to the first embodiment in that it has an estimation unit 901. The hardware configuration of the control unit 9 can be the same as that shown in FIG.

[0118] The function of the estimation unit 901 can be realized by the external I / F 917 shown in Fig. 7 and the CPU 911 executing processing defined in a program stored in the ROM 912. The function of the estimation unit 901 may be included in a configuration other than the control unit 9. For example, an external device such as a microcomputer or a PC that can communicate with the control unit 9 may have the function of the estimation unit 901.

[0119] The estimation unit 901 estimates the position of the viewer's cornea K based on the light emission timing of each light-emitting unit of the detection light source 131 and the detection signal output from the detection light-receiving unit 132. The estimation unit 901 acquires image data Im obtained from an external device, and converts the image data into control signals based on information regarding the position of the cornea K estimated by the estimation unit 901, and outputs the control signals to each of the light source control unit 902, the scanning control unit 903, and the deflection control unit 904.

[0120] Based on the control signal input from the estimation unit 901, the light source control unit 902 outputs a drive signal D1 to the light source 1 and a drive signal D4 to the detection light source 131, thereby driving the light source 1 and the detection light source 131. Based on the control signal input from the estimation unit 901, the scanning control unit 903 outputs a drive signal D2 to the light scanning unit 3, thereby driving the light scanning unit 3. Based on the control signal input from the estimation unit 901, the deflection control unit 904 outputs a drive signal D3 to the light deflection unit 2, thereby driving the light deflection unit 2.

[0121] (Functions and Effects of the Retinal Projection Type Image Display Device 50d) For example, if the observer's eyeball E tilts in response to a change in the observer's line of sight, the display range 60 shown in FIG. 4 may shift from the observer's field of view, and the image may not be displayed at the desired position in the observer's field of view.

[0122] In this embodiment, the detection unit 13 detects the position of the observer's pupil or cornea, and the control unit 9 controls the operation of the light deflection unit 2 so that the position of the image formed by the light scanning unit 3 changes according to the detection result by the detection unit 13. As a result, the retinal projection type image display device 50d can reduce deviation of the display range 60 from the observer's field of view even when the observer's eyeball E is tilted, and can display the image at a desired position in the observer's field of view.

[0123] [Example] Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

[0124] Fig. 16 is a schematic top view showing a retinal projection image display device 50e according to Example 1. Fig. 17 is a schematic top view showing a retinal projection image display device 50f according to Example 2. Fig. 18 is a schematic top view showing a retinal projection image display device 50g according to Example 3. Fig. 19 is a schematic top view showing a retinal projection image display device 50h according to Example 4. In Figs. 16 to 19, the light beam representing light L is a light beam when the inclination of both the light deflection unit 2 and the light scanning unit 3 is 0 degrees with respect to the optical axis.

[0125] In Examples 1 to 4, a part of the first optical system 5 is disposed between the light source 1 and the optical member 7. In Examples 1 to 4, an exit pupil EP is formed at a position subsequent to the light guiding unit 4, i.e., in the optical path between the light guiding unit 4 and the pupil P. By placing the eye at the position of the exit pupil EP, the observer can observe the image without any loss of the image. When the light guiding plate 11 is disposed, the light guiding plate 11 can be made thinner by disposing the light guiding plate 11 so that the exit pupil EP is located at an appropriate position on the light guiding plate 11.

[0126] 18, the light deflection unit 2 and the light scanning unit 3 can be disposed close to each other. Also, the width of the retinal projection type image display device 50g in the direction in which the light deflection unit 2 and the light scanning unit 3 are aligned can be narrowed.

[0127] In Example 4 shown in FIG. 19, the light guiding unit 4 includes a reflecting unit 41. The light L scanned by the optical scanning unit 3 is reflected by the reflecting unit 41 toward the partially reflecting surface 70 of the optical member 7, and the light L reflected by the reflecting unit 41 and transmitted through the partially reflecting surface 70 is guided to the pupil P. In the example shown in FIG. 19, the position of the pupil P approximately coincides with the position of the exit pupil EP. With this configuration, the light that forms an image and is scanned by the optical scanning unit 3 follows an optical path that travels back and forth within the light guiding unit 4. This allows the retinal projection type image display device 50h to be miniaturized.

[0128] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments of the present invention without departing from the scope of the claims.

[0129] All ordinal numbers, quantitative numbers, and other figures used in the description of the embodiments of the present invention are provided as examples to specifically explain the technology of the present invention, and the present invention is not limited to the illustrated figures. Furthermore, the connection relationships between components are provided as examples to specifically explain the technology of the present invention, and do not limit the connection relationships that realize the functions of the present invention.

[0130] For example, aspects of the present invention are as follows. <1> a light deflection unit that deflects light emitted from the light source; a light scanning unit that scans the light deflected by the light deflection unit using a deflection surface to form the image; a light guiding unit that guides the light scanned by the light scanning unit to the pupil of the observer; a first optical system that suppresses divergence of transmitted light; and a second optical system that suppresses divergence of transmitted light, wherein the light deflection unit changes the incident position of light on the deflection surface to change the position at which the image is formed by the light scanning unit, the first optical system is located on an optical path between the light source and the light deflection unit, and is also located on an optical path between the light deflection unit and the second optical system, and the second optical system is located on an optical path between the first optical system and the light scanning unit, and is also located on an optical path between the light scanning unit and the light guiding unit, and the light deflection unit, the light scanning unit, and the pupil are in a conjugate relationship with each other. <2> a first optical system that suppresses divergence of transmitted light; and a second optical system that suppresses divergence of transmitted light. The light deflection unit changes the position at which light is incident on the deflection surface, thereby changing the formation position of the image to be projected onto the retina. The first optical system is located on an optical path between the light source and the light scanning unit, and is also located on an optical path between the scanning unit and the second optical system. The second optical system is located on an optical path between the first optical system and the light deflection unit, and is also located on an optical path between the light deflection unit and the light guide unit. The light deflection unit, the light scanning unit, and the pupil are in a conjugate relationship with each other. <3> an optical element having a partially reflective surface, the optical element being located on an optical path between the first optical system and the second optical system, the partially reflective surface transmitting or reflecting light emitted from the light source, light deflected by the light deflection unit, and light scanned by the light scanning unit, respectively; <1> or the above <2> 1. A retinal projection display device according to claim 1. <4> the partially reflective surface reflects the light emitted from the light source toward the first optical system, transmits the light that has been reflected by the partially reflective surface, then passes through the first optical system, is deflected by the optical deflection unit, and passes through the first optical system, transmits the light that has passed through the partially reflective surface, then passes through the second optical system, is scanned by the optical scanning unit, and reflects the light that has passed through the second optical system toward the light guiding unit; <3> 1. A retinal projection type image display device according to claim 1. <5> The first optical system forms a first intermediate image that is an image of the light source, and the second optical system forms a second intermediate image that is an image of the first intermediate image. <3> or the above <4> 1. A retinal projection type image display device according to claim 1. <6> the first intermediate image overlaps with the second intermediate image; <5> 1. A retinal projection type image display device according to claim 1. <7> the first intermediate image and the second intermediate image overlap on the optical path between the second optical system and the optical member; <6> 1. A retinal projection type image display device according to claim 1. <8> the partially reflective surface has a higher reflectivity for S-polarized light incident at an incident angle of 45° than for P-polarized light incident thereon; <3> From the above <7> The retinal projection type image display device according to any one of the above items. <9> a first quarter-wave plate in an optical path between the optical member and the optical deflection unit; <8> 1. A retinal projection type image display device according to claim 1. <10> a second quarter-wave plate in the optical path between the optical member and the optical scanning unit; <8> 1. A retinal projection type image display device according to claim 1. <11> the partially reflective surface includes a first partially reflective surface and a second partially reflective surface, the first partially reflective surface reflects the light emitted from the light source toward the first optical system, and transmits the light that has been reflected by the first partially reflective surface, passed through the first optical system, deflected by the light deflection unit, and passed through the first optical system; the second partially reflective surface reflects the light that has passed through the first partially reflective surface, passed through the second optical system, scanned by the light scanning unit, and passed through the second optical system toward the light guiding unit; <3> From the above <10> The retinal projection type image display device according to any one of the above items. <12> The optical member includes a first optical member and a second optical member, the first optical member having the first partially reflective surface, and the second optical member having the second partially reflective surface. <11> 1. A retinal projection type image display device according to claim 1. <13> the light guide unit includes a reflecting unit, and reflects the light scanned by the optical scanning unit toward the partially reflecting surface of the optical member by the reflecting unit, and guides the light that has been reflected by the reflecting unit and then transmitted through the partially reflecting surface to the pupil; <3> From the above <12> The retinal projection type image display device according to any one of the above items. <14> a support that supports the light source, the light deflection unit, the light scanning unit, the light guiding unit, the first optical system, the second optical system, and the optical member; <3> From the above <13> The retinal projection type image display device according to any one of the above items. <15> a detection unit that detects the position of the pupil or cornea of ​​the observer, and a control unit that controls the operation of the light deflection unit so that the position of the image formed by the light scanning unit changes in accordance with the detection result by the detection unit, <1> From the above <14> The retinal projection type image display device according to any one of the above items. [Explanation of symbols]

[0131] 1 light source 2 Light deflection section 3 Optical scanning unit 4 Light guide section 41 Reflector 5 First optical system 6 Second optical system 7, 7b Optical components 7-1 First optical member 7-2 Second optical member 70 Partially reflective surface 70-1 1st partial reflective surface 70-2 Second partial reflective surface 71, 72, 73 Prism 81 First quarter wave plate 82 Second quarter wave plate 9 Control Unit 10a 1st intermediate image 10b Second intermediate image 11 Light guide plate 12 Reflective member 13 Detector 131 Detection light source 132 Light receiving unit for detection 60 display range 60-1, 60-2, 60-3, 60-4, 60-5, 60-6, 60-7, 60-8, 60-9 Image area 911 CPU 912 ROM 913 RAM 914 Light source driving circuit 915 Scanning drive circuit 916 Deflection drive circuit 917 External I / F 901 Estimation Department 902 Light source control unit 903 Scanning control section 904 Deflection control section 102 Support substrate 102a, 102b, 102c, 102d Connections 113a, 113b, 113c, 113d Piezoelectric drive unit 110 First member 120 Second member 130 Third Component 140 Fourth Element 91 Support substrate 92 Moving parts 30 Deflection surface 92b Torsion Bar 92c Piezoelectric material 92d Support part 93a Beam section 93 Serpentine beam 94 Serpentine beam 95 Electrode connection part 50, 50a, 50b, 50c, 50d, 50e, 50f, 50g, 50h Retinal projection image display device 50LC optical axis 100 support 151 Crane 152 Translucent material 153 frames B System Bus D1, D2, D3, D4 drive signals E Eyeball EP exit pupil Im Image Data K cornea L light P pupil S1 Detected light S2 reflected light [Prior art documents] [Patent documents]

[0132] [Patent Document 1] U.S. Patent No. 10,983,346

Claims

1. A retinal projection image display device that projects an image onto the retina of an observer, A light source and a light deflection unit that deflects the light emitted from the light source; an optical scanning unit that scans the light deflected by the optical deflection unit with a deflection surface to form the image; a light guide unit that guides the light scanned by the optical scanning unit to the pupil of the observer; and a first optical system that suppresses divergence of the transmitted light. a second optical system that suppresses divergence of transmitted light, the optical deflection unit changes the position at which light is incident on the deflection surface, thereby changing the position at which the image is formed by the optical scanning unit; the first optical system is located on an optical path between the light source and the optical deflection unit, and is also located on an optical path between the optical deflection unit and the second optical system, the second optical system is located on an optical path between the first optical system and the optical scanning unit, and is also located on an optical path between the optical scanning unit and the light guiding unit, the optical deflection unit, the optical scanning unit, and the pupil are in a conjugate relationship with each other; Retinal projection type image display device.

2. A retinal projection image display device that projects an image onto the retina of an observer, A light source and an optical scanning unit that scans the light emitted from the light source with a deflection surface to form the image; an optical deflection unit that deflects the light scanned by the optical scanning unit; a light guide unit that guides the light deflected by the light deflection unit to the pupil of the observer; a first optical system that suppresses divergence of transmitted light; a second optical system that suppresses divergence of transmitted light, the light deflection unit changes a position where light is incident on the deflection surface, thereby changing a formation position of an image to be projected onto the retina; the first optical system is located on an optical path between the light source and the optical scanning unit, and is also located on an optical path between the optical scanning unit and the second optical system, the second optical system is located on an optical path between the first optical system and the optical deflection unit, and is also located on an optical path between the optical deflection unit and the light guiding unit, the optical deflection unit, the optical scanning unit, and the pupil are in a conjugate relationship with each other; Retinal projection type image display device.

3. an optical element having a partially reflective surface; the optical member is located on an optical path between the first optical system and the second optical system, 2. The retinal projection type image display device according to claim 1, wherein the partially reflective surface transmits or reflects the light emitted from the light source, the light deflected by the light deflection unit, and the light scanned by the light scanning unit.

4. The partially reflective surface is reflecting the light emitted from the light source toward the first optical system; the light that has been reflected by the partially reflecting surface, transmitted through the first optical system, deflected by the light deflection unit, and transmitted through the first optical system is transmitted; 4. The retinal projection type image display device according to claim 3, wherein the light transmitted through the partially reflective surface, then transmitted through the second optical system, is scanned by the optical scanning unit, and the light transmitted through the second optical system is reflected toward the light guiding unit.

5. the first optical system forms a first intermediate image that is an image of the light source; 4. The retinal projection type image display device according to claim 3, wherein the second optical system forms a second intermediate image which is an image of the first intermediate image.

6. 6. A retinal projection type image display device according to claim 5, wherein the first intermediate image overlaps with the second intermediate image.

7. 7. The retinal projection type image display device according to claim 6, wherein the first intermediate image and the second intermediate image overlap in the optical path between the second optical system and the optical member.

8. 4. The retinal projection type image display device according to claim 3, wherein the partially reflective surface has a higher reflectance for S-polarized light incident at an incident angle of 45 degrees than for P-polarized light incident thereon.

9. 9. The retinal projection type image display device according to claim 8, further comprising a first quarter-wave plate in the optical path between the optical member and the light deflecting unit.

10. 9. The retinal projection type image display device according to claim 8, further comprising a second quarter-wave plate in the optical path between the optical member and the optical scanning unit.

11. the partially reflective surface includes a first partially reflective surface and a second partially reflective surface; The first partially reflective surface is reflecting the light emitted from the light source toward the first optical system; transmit the light that has been reflected by the first partially reflecting surface, transmitted through the first optical system, deflected by the light deflection unit, and transmitted through the first optical system; The second partially reflective surface is 4. A retinal projection type image display device according to claim 3, wherein the light transmitted through the first partially reflective surface, then transmitted through the second optical system, is scanned by the optical scanning unit, and the light transmitted through the second optical system is reflected toward the light guiding unit.

12. the optical member includes a first optical member and a second optical member, the first optical member has the first partially reflective surface, 12. The retinal projection type image display device according to claim 11, wherein the second optical member has the second partially reflective surface.

13. 4. The retinal projection type image display device according to claim 3, wherein the light guide unit includes a reflecting unit, and the reflecting unit reflects the light scanned by the optical scanning unit toward the partially reflective surface of the optical element, and guides the light that has been reflected by the reflecting unit and then transmitted through the partially reflective surface to the pupil.

14. 4. The retinal projection type image display device according to claim 3, further comprising a support that supports the light source, the light deflection unit, the light scanning unit, the light guiding unit, the first optical system, the second optical system, and the optical member.

15. a detection unit that detects the position of the pupil or cornea of ​​the viewer; 15. The retinal projection type image display device according to claim 1, further comprising: a control unit that controls the operation of the light deflection unit so that the position of the image formed by the light scanning unit changes depending on the detection result by the detection unit.

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