Projection device

Abstract

The projection device according to an embodiment of the present disclosure includes: a display device; a reflector for reflecting light emitted from the display device in a predetermined direction; one or more condenser lenses; and an antireflector disposed at the focal length of the condenser lenses and reflecting light incident via the reflector and the condenser lenses in the incident direction.

Description

Technical Field

[0001] This disclosure relates to projection devices, for example, used as head-up displays. Background Technology

[0002] For example, PTL 1 discloses an information display device that mitigates installation location limitations by using a light reflector having multiple unit areas arranged two-dimensionally on a main surface.

[0003] Reference List

[0004] Patent documents

[0005] Patent Document 1: International Publication No. WO 2018 / 061444 Summary of the Invention

[0006] In addition, it is required that the projection equipment used to display driver assistance information to the vehicle driver display a focused virtual image with a wide field of view.

[0007] The aim is to provide a projection device that enables the display of a focused virtual image using a wide field of view.

[0008] A projection device according to one embodiment of the present disclosure includes: a display device; a reflector that reflects light emitted from the display device to a predetermined direction; one or more condenser lenses; and a retroreflector disposed at the focal length of the condenser lenses and reflecting incident light via the reflector and the condenser lenses to the incident direction.

[0009] In a projection apparatus according to an embodiment of the present disclosure, one or more condenser lenses are disposed between a reflector and a retroreflector, such that the retroreflector is located at the focal length. As a result, the light collected by the condenser lenses is incident on the retroreflector, and the diffusion of the returning light emitted from the retroreflector is greatly reduced. Attached Figure Description

[0010] [ Figure 1 ] Figure 1 This is a schematic diagram illustrating a configuration example of a projection device according to one embodiment of the present disclosure.

[0011] [ Figure 2 ] Figure 2 It shows Figure 1 The diagram shows a functional block diagram of the configuration of the display device.

[0012] [ Figure 3 ] Figure 3 This is a planar schematic diagram of a retroreflector.

[0013] [ Figure 4 ] Figure 4 It is used to describe including Figure 3 A schematic diagram of the retroreflective element in the retroreflector shown.

[0014] [ Figure 5 ] Figure 5 It is used to describe Figure 3 The diagram shows a cross-sectional view of the retroreflector.

[0015] [ Figure 6 ] Figure 6 It shows Figure 1 The diagram shows an example of a projection device installed on a vehicle.

[0016] [ Figure 7A ] Figure 7A It is a diagram used to describe the pupil position that enables visual identification of wide-angle images.

[0017] [ Figure 7B ] Figure 7B It is used to describe Figure 7A The diagram shows each light beam incident into the human pupil.

[0018] [ Figure 8 ] Figure 8 It shows Figure 6 A schematic diagram illustrating an example of the configuration of a display device in a projection device shown.

[0019] [ Figure 9 ] Figure 9 This is a perspective view of a configuration example of an optical pupil replication device.

[0020] [ Figure 10 ] Figure 10 It shows the incident light. Figure 9 A diagram illustrating the light pattern of the pupil replication device shown.

[0021] [ Figure 11 ] Figure 11 This is a schematic diagram illustrating an example of the configuration of a typical projection device.

[0022] [ Figure 12 ] Figure 12 This is a schematic diagram used to describe the pattern of reflected light from a retroreflector in a typical projection device.

[0023] [ Figure 13 ] Figure 13 This is a schematic diagram used to describe the pattern of reflected light from a retroreflector in a typical projection device where the pupil is reproduced.

[0024] [ Figure 14 ] Figure 14 It is used to describe from Figure 1 A schematic diagram of the pattern of light return from the retroreflector in the configuration of the projection device shown.

[0025] [ Figure 15 ] Figure 15 This is a schematic diagram illustrating a configuration example of a display device according to a first variation of the present disclosure.

[0026] [ Figure 16 ] Figure 16 This is a schematic diagram illustrating a configuration example of a projection device according to a second variation of the present disclosure.

[0027] [ Figure 17 ] Figure 17 This is a schematic diagram illustrating a configuration example of a projection device according to a third variation of the present disclosure.

[0028] [ Figure 18 ] Figure 18 This is a schematic diagram illustrating a configuration example of a projection device according to a fourth variation of the present disclosure. Detailed Implementation

[0029] In the following, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. The following descriptions are specific examples of the present disclosure, and the present disclosure is not limited to the following models. Furthermore, the arrangement, dimensions, aspect ratios, etc., of the components shown in the accompanying drawings of the present disclosure are not limited to these. Note that the descriptions are given in the following order.

[0030] 1. Implementation method (example of a projection device with a condenser lens positioned between a reflector and a retroreflector)

[0031] 2. Variations

[0032] 2-1. First Modification (Another Example of a Display Device)

[0033] 2-2. Second variation (another example of a projection device)

[0034] 2-3. Third variation (another example of a projection device)

[0035] 2-4. Fourth Variation (Another Example of a Projection Device)

[0036] <1. Implementation Method>

[0037] Figure 1 A schematic configuration of a projection device (projection device 1) according to one embodiment of the present disclosure is shown. For example, projection device 1 is a head-up display (HUD) system used to display speed, navigation, etc. to the driver on the front seat of a vehicle and to display a virtual image including driving support information and attention-grabbing information using light reflection from the windshield.

[0038] <Projection Equipment Configuration>

[0039] The projection device 1 includes a display device 10, a reflector 20, a retroreflector 30, and a condenser lens 40.

[0040] Here, display device 10 corresponds to a specific example of a "display device" according to one embodiment of the present disclosure. Reflector 20 corresponds to a specific example of a "reflector" according to one embodiment of the present disclosure. Retroreflector 30 corresponds to a specific example of a "retroreflector" according to one embodiment of the present disclosure. Condensing lens 40 corresponds to a specific example of a "condensing lens" according to one embodiment of the present disclosure.

[0041] Figure 2 This is a functional block diagram illustrating an example of the configuration of the display device 10. The display device 10 projects a virtual image in front of an observer 100. For example, the display device 10 is coupled via an interface (I / F) to an external image supply device such as a computer (e.g., a personal computer (PC)) (not shown) or various image players, and projects a virtual image based on image signals input to the interface.

[0042] For example, the display device 10 includes a light source device 11, a controller 12, a light source driver 13, a light modulation device 14, an image processor 15, a frame memory 16, a panel driver 17, a projection optics system driver 18, and a projection optics system 19.

[0043] Although not specifically shown, the light source device 11 includes a light source driver that drives the light source and a current value setting unit that sets each current value when driving the light source. The light source driver generates a current having a current value set by the current value setting unit, based on power supplied from a power supply circuit (not shown) and in sync with a signal input from the light source driver 13. Each generated current is supplied to the light source.

[0044] The controller 12 controls the light source driver 13, the image processor 15, the panel driver 17, and the projection optics system driver 18.

[0045] The light source driver 13 outputs a signal for controlling the timing of light emission of the light source installed in the light source device 11. The light source driver 13 includes, for example, a PWM setting unit, a PWM signal generation unit, a limiter, etc. (not shown), and controls the light source driver of the light source device 11 to turn the light source on and off or adjust its brightness based on the control of the controller 12 and the PWM controlling the light source.

[0046] The light modulation device 14 modulates the light (illumination light) output from the light source device 11 based on the image signal and generates image light. The light modulation device 14 includes, for example, three light valves corresponding to the RGB colors described later. Examples of the light modulation device 14 include a liquid crystal display panel (panel (B)) that modulates blue light (B), a liquid crystal display panel (panel (R)) that modulates red light (R), and a liquid crystal display panel (panel (G)) that modulates green light (G). The RGB color light modulated by the light modulation device 14 is combined by a cross dichroic prism (not shown) and guided to the projection optical system 19.

[0047] The image processor 15 acquires an image signal input from an external source, determines the image size, determines the resolution, and determines whether the image is a still image or a moving image. If the image is a moving image, the image processor 15 determines attributes of the image data, such as the frame rate. Furthermore, if the resolution of the acquired image signal differs from the display resolution of the light modulation device 14, a resolution conversion process is performed. The image processor 15 develops each processed image into the frame memory 16 for each frame, and outputs the image for each frame developed into the frame memory 16 to the panel driver 17 as a display signal.

[0048] The panel driver 17 drives the light modulation device 14. The driving of the panel driver 17 changes the transmittance of light in each pixel of the light modulation device 14, and forms an image.

[0049] The projection optics system driver 18 includes a motor that drives a lens disposed in the projection optics system 19. Under the control of the controller 12, the projection optics system driver 18 drives, for example, the projection optics system 19 and performs, for example, zoom adjustment, focus adjustment, aperture adjustment, etc.

[0050] The projection optical system 19 includes a lens group and the like for forming an image of light modulated by the light modulation device 14.

[0051] Note that, in addition to the three-panel method using three liquid crystal display panels described in the light modulation device 14, the display device 10 can also be configured as a single-panel time-division projection device using a single liquid crystal display panel.

[0052] For example, the reflector 20 reflects the light emitted from the display device 10 to a predetermined direction. Here, the reflector 20 transmits the light emitted from the display device 10 toward the retroreflector 30, and through partial reflection, reflects the light reflected by the retroreflector 30 (return light) toward the vicinity of the observer 100's eye.

[0053] The retroreflector 30 has a mechanism for reflecting light back to the optical axis of the incident light. In the retroreflector 30, a plurality of retroreflective elements 31 are arranged periodically in a two-dimensional array.

[0054] Figure 3 The planar configuration of the retroreflector 30 is schematically shown. Figure 4 The arrangement of multiple retroreflective elements 31 constituting the retroreflector 30 is schematically shown. For example, the retroreflective elements 31 are formed by combining three plane mirrors orthogonal to each other and having reflective surfaces on their inner sides to allow the formation of the vertices of a cube. Specifically, as... Figure 4 As shown, by combining three surfaces S1, S2, and S3 orthogonally to each other, the retroreflective element 31 has a triangular pyramid-shaped recess 31c on the inner side of the three surfaces S1, S2, and S3. In the retroreflector 30 with such retroreflective elements 31 arranged in a two-dimensional array, when viewed from directly above, equilateral triangles are closely arranged, for example, as... Figure 3 As shown, light that has reached any reflective surface is reflected by the corner reflectors on the three surfaces and returns to the direction of incidence (retroreflection).

[0055] Figure 5 Schematic illustration along Figure 3 The cross-sectional configuration of the retroreflector 30 is shown as intercepted by line I-I'. The retroreflector 30 has a pair of surfaces 30S1 and 30S2 opposite to each other. A light beam incident on each retroreflective element 31 (incident light L0) is subsequently subjected to repeated specular reflection on the reflecting surface S, which comprises three surfaces S1, S2, and S3 orthogonally combined with each other, for example, as shown... Figure 5 As shown in the diagram. As a result, the beam eventually returns to the incident direction as the return beam L1.

[0056] The condenser lens 40 collects the generally parallel light L emitted from the display device 10 and transmitted by the reflector 20 into a predetermined spot diameter and causes the light L to be incident on the retroreflector 30. Furthermore, although details will be described later, the condenser lens 40 emits the light L (including the light back-reflected from the retroreflector 30 and the light reflected with a width within a specific angular range around the retroreflection direction) toward the reflector 20 as generally parallel light.

[0057] Condensing lens 40 is, for example, collimating lens 41 and is configured, for example, in a plan view (e.g., see reference 41). Figure 6 The entire surface of the retroreflector 30 can be covered by a single lens. Alternatively, if the entire surface of the retroreflector 30 cannot be covered by a single lens, multiple lenses can be arranged in parallel in two dimensions to address this situation.

[0058] In the projection device 1 according to this embodiment, light L emitted from the display device 10 positioned above the observer 100 is incident on the retroreflector 30 positioned below the observer 100 via a reflector 20 and a condenser lens 40. Light from each image height is incident on the retroreflector 30 as converging light before forming an image, and undergoes repeated specular reflection at each retroreflective element 31, resulting in it returning to the incident direction as diverging light. The diverging light emitted from the retroreflector 30 is transformed into substantially parallel light by the condenser lens 40, partially reflected by the reflector 20 which is obliquely positioned in front of the observer 100, and incident near the observer 100's eyes. As a result, a far-field virtual image with a wide field of view (FOV) is displayed in front of the observer 100.

[0059] <Installation Example to Vehicle>

[0060] Figure 6 An example configuration of the projection device 1 described above, installed on a vehicle (projection device 1A), is shown. For example, in projection device 1A, the display device 10 is disposed on the exterior of the vehicle 50 (e.g., on the roof) together with the reflector device 21, and the retroreflector 30 and the condenser lens 40 (collimating lens 41) are disposed on the dashboard 52. In projection device 1, the reflector device 21 and the windshield 51 of the vehicle 50 correspond to a specific instance of a "reflector" according to one embodiment of the present disclosure.

[0061] Figure 7A The pupil position is described, which enables visual recognition of wide-angle images. Figure 7B Described Figure 7A The light rays shown, representing each of heights A, B, and C, are incident on the eye of observer 100. Consider the conjugate points of the light rays incident on the eye of observer 100. For example, as... Figure 7A As shown, for example, light emitted from the display device 10 at each image height (hereinafter referred to as image heights A, B, and C) of points A, B, and C of the light modulation device 14 is emitted from the display device 10 via a polarizing beam splitter (PBS) 141 and multiple projection lenses 191A and 191B. The light emitted from each of image heights A, B, and C is reflected by the mirror assembly 21, propagates through space, and is returned by the retroreflector 30 to approximately the incident direction. The returned light from the retroreflector 30 travels towards the eye of the observer 100 through partial reflection by the windshield 51. At this time, as... Figure 7BAs shown, the light emitted from images A, B, and C overlaps again at the pupil position of observer 100's eye, forming an image on the retina, and the virtual image is visually recognized. That is, the overlapping position of the light patches is only the point (eyebox) where the entire image can be visually recognized, and if the eyebox is outside the pupil position of observer 100's eye, the image cannot be visually recognized. However, because the pupil position of observer 100's eye changes due to vehicle vibrations during driving or individual differences in seating height, an enlarged eyebox is required.

[0062] For example, an enlarged eye box can be made as follows.

[0063] Figure 8 An example of a configuration for a magnified display device (display device 10A) that accommodates the eyebox in the body-axis direction (X-axis direction) and eye-to-eye direction (Y-axis direction) of observer 100 is shown. Display device 10A illuminates a light source (light L) carrying video information using, for example, an intensity modulation panel 14A employing a liquid crystal on silicon (LCOS) method or a digital illumination processing (DLP) method. For example, display device 10A includes: an intensity modulation panel 14A; a PBS 141; a projection lens 192 having a pupil at an emission port and including multiple lenses; and a pupil replication device 60 extending in the X-axis and Y-axis directions. As a light source, semiconductor diodes (LD: laser diodes) and light-emitting diodes (LED: light-emitting diodes) can be used. Alternatively, excitation light sources such as phosphors can be used.

[0064] Figure 9 The planar and cross-sectional configurations of the pupil replication device 60 are schematically shown. The pupil replication device 60 is a light guide panel having a pair of surfaces 61S1 and 61S2 facing each other. For example, the light guide panel 61 has a total reflection region 62 and an emission region 63. In the total reflection region, a plurality of semi-reflective mirrors 621 with a predetermined tilt (e.g., approximately 45° relative to the body axis direction (X-axis direction) of the observer 100) are arranged in the X-axis direction. In the emission region, a plurality of semi-reflective mirrors 631 extending in the X-axis direction are arranged in the Y-axis direction. An incident portion 64 is provided on the surface 61S2, opposite to the surface 61S1 which serves as the light-emitting surface of the light guide panel 61.

[0065] In the pupil replication apparatus 60, the plurality of semi-reflective mirrors 621 constituting the total reflection region 62 correspond to a specific example of a "first semi-reflective mirror group" according to an embodiment of the present disclosure. The plurality of semi-reflective mirrors 631 constituting the emission region 63 correspond to a specific example of a "second semi-reflective mirror group" according to an embodiment of the present disclosure.

[0066] The pupil replication device 60 is disposed at the pupil position of the projection lens 192. Light L incident from the projection lens 192 onto the incident portion 64 propagates through the total internal reflection region 62 and is reflected in the Y-axis direction by each of the semi-reflective mirrors 621 arranged in the X-axis direction. For example, as... Figure 10 As shown, the light L reflected by each of the semi-reflecting mirrors 621 is reflected by each of the semi-reflecting mirrors 631 arranged in the Y-axis direction to the Z-axis direction and emitted from the surface 61S1. For example, as Figure 9 As shown, in a light guide panel 61 with 10 semi-reflective mirrors 621 arranged in the X-axis direction and 5 semi-reflective mirrors 631 arranged in the Y-axis direction, an incident beam is expanded (replicated) into 10 beams in the total reflection region 62 and expanded (replicated) into 50 beams in the emission region 63 for emission. That is, 50 pupils are replicated in the X-axis and Y-axis directions.

[0067] <Functions and Effects>

[0068] In the projection device 1 according to this embodiment, a condenser lens 40 is disposed between the reflector 20 and the retroreflector 30, such that the retroreflector 30 is located at the focal length position. As a result, since the light L collected by the condenser lens 40 is incident on the retroreflector 30, for example, even if the angle of the returned light emitted from the retroreflector 30 becomes wider, the light L becomes light that is approximately parallel to the condenser lens disposed at the focal length position, and the width of the returned light emitted from the retroreflector 30 is greatly reduced.

[0069] This will be described below.

[0070] In recent years, HUD systems have been developed that display speed, navigation, and other information to the driver from the front seat of the vehicle, and use the reflection of light from the windshield to display virtual images that include driver support information and attention-grabbing information.

[0071] Typically, due to the size limitations of the display device, existing HUDs are limited to displaying information only within an area with a field of view of approximately 10 degrees (the central area in front). On the other hand, in the world of computer graphics (CG), there are many instances where prompts and augmented reality (AR) information are overlaid and displayed across the entire windshield. However, no device actually implements this, and no such device is installed in actual vehicles.

[0072] There exists a method in which, if a display device is placed in the dashboard area, the phantom image appears to float over a wide area using the Pepper illusion method. Using this method, because the phantom image appears to float only a certain distance between the display device and the windshield, a distant phantom image cannot be displayed. Therefore, there is no technology for displaying a phantom image with a wide field of view and in a distant manner, and no technology for realizing an idealized CG world exists.

[0073] Figure 11 An example of the configuration of a general projection device (projection device 1000A) is shown. The general projection device 1000A uses a light source unit located below the dashboard 1012 of the front seat of a vehicle, a reflective optical system including a display panel 1013 that expands the light emitted from the unit, and a concave mirror 1014, and the concave mirror optical system delivers light to the eyes of the driver (observer 100). Figure 11 As shown, the diffused light reaches the observer 100 to allow the virtual image to be perceived as floating in front of the observer 100, which has a conjugate relationship with the virtual light source. However, as mentioned above, the FOV of the projection device 1000A is limited to approximately 10 degrees.

[0074] As a method for displaying a virtual image with a wide field of view (FOV) in front of observer 100 (at a long distance), for example, such as Figure 12 As shown, consider a projection device 1000B using a retroreflective element 1030. The retroreflective element 1030 has a mechanism that reflects light back to the optical axis of the incident light. However, in reality, due to various factors, light is reflected with a width within a specific angular range around the retroreflection direction.

[0075] exist Figure 12 In the projection device 1000B shown, light back-reflected from the retroreflector 30 (reflected light Lx) is partially reflected as parallel light by the mirror 1020 and incident near the eye of the observer 100. On the other hand, light reflected with a width within a specific angle around the retroreflection direction (angle-spread light Ly) is partially reflected as non-parallel light by the mirror 1020 and incident near the eye of the observer 100 to overlap with the retroreflected light Lx. At this time, the angle-spread light Ly forms an image at a retinal position offset from the retinal position of the observer 100, while the retroreflected light Lx forms an image that results in focus degradation.

[0076] Figure 13A schematic configuration of the projection device 1000C is shown, in which a pupil copying device is combined to magnify the eye box. As in the pupil copying device 60 described above, in the projection device 1000C using a pupil multi-copy type pupil copying device, when the pupil image 1010A (video at a specific projection distance) of the light guide panel is incident on the eye of the observer 100, when the angular expansion light Ly of the adjacent pupil image 1010B (video at a different projection distance) is incident on the eye of the observer 100, the original pupil image 1010A and the adjacent pupil image 1010B overlap, resulting in more severe focus degradation.

[0077] On the other hand, in this embodiment, the condenser lens 40 is disposed between the reflector 20 and the retroreflector 30, and the retroreflector 30 is located at the focal length of the condenser lens 40. For example, generally parallel light L emitted from the display device 10 disposed above the observer 100 and reflected by the reflector 20 is collected on the retroreflector 30 having the condenser lens 40. Although the light L reflected by the retroreflector 30 includes retroreflected light Lx that is reflected back to the optical axis of the incident light as is and angularly expanded light Ly, the retroreflected light Lx and angularly expanded light Ly are returned to generally parallel light using the condenser lens 40, such as... Figure 14 As shown. As a result, for example, because the angularly extended light Ly partially reflected by the mirror 1020 is incident near the eye of the observer 100 without overlapping with the beam from the adjacent pupil image, focus degradation is prevented.

[0078] As described above, a projection device can be provided that enables the display of a focused virtual image using a wide field of view.

[0079] Furthermore, in the projection device 1 according to this embodiment, a condenser lens 40 is disposed between the reflector 20 and the retroreflector 30, and the retroreflector 30 is located at the focal length of the condenser lens 40. Therefore, the light L collected by the condenser lens 40 is incident on the retroreflector 30. Compared to the projection device 1000B with a substantially parallel light L incident on the retroreflector element 1030, this allows for miniaturization of the retroreflector.

[0080] In addition, Figure 6 In the projection device 1A according to this embodiment shown in the figures, for example, such as Figure 8 As shown, by arranging the pupil replication device 60, which replicates the pupil in the body axis direction (X-axis direction) and eye-to-eye direction (Y-axis direction) of the observer 100, at the pupil position X of the display device 10A, the eye box can be magnified, thereby enabling visual recognition of the entire image in the body axis direction and eye-to-eye direction of the observer 100.

[0081] Next, first to fourth modifications of this disclosure will be described. In the following, components similar to those in the above embodiments will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0082] <2. Variations>

[0083] <2-1. First Variation>

[0084] Figure 15 An example configuration of a display device (display device 10B) according to a first variation of the present disclosure is shown.

[0085] For projection devices according to this disclosure (e.g., projection device 1), a display device that emits substantially parallel light is used. However, for example, as... Figure 15 As shown, by using an infinity-focusing projection lens 19A composed of a large number of lenses as the projection optics system 19, the parallelism of the projected light in each field of view is improved. Therefore, it is possible to provide a projection device that can display a more focused virtual image with a wide field of view.

[0086] <2-2. Second Variation>

[0087] Figure 16 A schematic configuration of a projection device (projection device 1B) according to a second variation of the present disclosure is shown. As in the above embodiment, the projection device 1B is used, for example, in a HUD system that displays speed, navigation, etc., to the driver on the front seat of a vehicle and uses light reflection from the windshield to display a virtual image including driving support information and attention-grabbing information.

[0088] In this embodiment, an example is shown where the collimating lens 41 is used as the condenser lens 40. However, the invention is not limited thereto. The projection device 1B according to this variation uses a Fresnel lens 42, which is thinner than the collimating lens 41, as the condenser lens 40.

[0089] In this way, in this modified example, since the Fresnel lens 42 is used as the condenser lens 40, the thickness of the lens can be reduced in the optical axis direction compared to the projection device 1 which uses the collimating lens 41.

[0090] <2-3. Third variation>

[0091] Figure 17 A schematic configuration of a projection device (projection device 1C) according to a third variation of the present disclosure is shown. As in the above embodiment, the projection device 1C is used, for example, in a HUD system that displays speed, navigation, etc. to the driver on the front seat of a vehicle and displays a virtual image including driving support information and attention-grabbing information using light reflection from the windshield.

[0092] In the above embodiments, an example of using the collimating lens 41 as the condenser lens 40 is shown. However, the present invention is not limited thereto. The projection device 1C according to this variation uses a lens array 43 having a focal length shorter than that of the collimating lens 41 as the condenser lens 40.

[0093] In this way, in this modified example, since the lens array 43 is used as a condenser lens 40, the focal length of the optical system can be reduced in the optical axis direction compared to the projection device 1 which uses a collimating lens 41.

[0094] <2-4. Fourth Variation>

[0095] Figure 18 A schematic configuration of a projection device (projection device 1D) according to a fourth variation of this disclosure is shown. As in the above embodiment, the projection device 1D is used, for example, in a HUD system that displays speed, navigation, etc., to the driver on the front seat of a vehicle and displays a virtual image including driving support information and attention-grabbing information using light reflection from the windshield.

[0096] In the above embodiments, an example is shown where the collimating lens 41 is used as the condenser lens 40. However, the present invention is not limited thereto. The projection device ID according to this modified example uses a concave mirror 44 as the condenser lens 40.

[0097] In this way, in this modified example, since the concave mirror 44 is used as the condenser lens 40, the length of the optical system can be reduced compared to the projection device 1, which uses the collimating lens 41, for example, the length of the partially folded linear optical system can be reduced.

[0098] As described above, embodiments and first to fourth variations have been presented. However, this disclosure is not limited to the embodiments, etc., and various modifications can be made. For example, the arrangement and number of components of the optical system shown in the above embodiments, etc., are merely examples and do not necessarily include all components. Furthermore, other components may be included.

[0099] Although examples have been described using projection-type display devices as display devices (e.g., implementation methods, etc.), the display device is not limited thereto. For example, a flat panel display can be used.

[0100] Note that the effects described in this article are examples and are not limited to this description; other effects are also possible.

[0101] This technology can have the following configuration. According to this technology with the following configuration, for example, because the light collected by the condenser lens is incident on the retroreflector, even if the angle of the returned light emitted from the retroreflector widens, the light becomes approximately parallel to the condenser lens positioned at the focal length, and the spread of the returned light emitted from the retroreflector 30 is significantly reduced. Therefore, a projection device can be provided that allows a focused virtual image to be displayed with a wide FOV. (1)

[0103] A projection device, comprising: Display device; A reflector reflects light emitted from the display device to a predetermined direction; One or more condenser lenses; and An antireflector is positioned at the focal length of a condenser lens and reflects light incident through the mirror and condenser lens back to the incident direction. (2)

[0105] According to the projection device in (1), the condenser lens is disposed between the reflector and the retroreflector. (3)

[0107] According to the projection device of (1) or (2), it also includes a pupil copying device, wherein, The body's axis is set as the X-axis, and the eye-to-eye direction is set as the Y-axis. The pupil replication device replicates the pupil conjugate point in the Y-axis direction, the X-axis direction, or both. (4)

[0109] According to the projection device in (3), the pupil copying device is disposed between the display device and the reflector. (5)

[0111] According to the projection device of (3) or (4), the pupil copying device includes a light guide panel, which includes a first semi-reflective mirror group and a second semi-reflective mirror group. The first semi-reflective mirror group includes a plurality of semi-reflective mirrors arranged in the X-axis direction, and the second semi-reflective mirror group includes a plurality of semi-reflective mirrors arranged in the Y-axis direction. (6)

[0113] The projection device according to any one of (1) to (5), wherein the condenser lens includes a Fresnel lens. (7)

[0115] The projection device according to any one of (1) to (5), wherein the condenser lens comprises a lens array. (8)

[0117] The projection device according to any one of (1) to (5), wherein the condenser lens includes a concave mirror. (9)

[0119] The projection device according to any one of (1) to (8) wherein the display device emits generally parallel light. (10)

[0121] The projection device according to any one of (1) to (8), wherein the display device includes an infinity-focusing projection lens. (11)

[0123] The projection device according to any one of (1) to (10) further includes a transparent plate disposed in the light path emitted from the display device. (12)

[0125] According to the projection device of (11), where, The reflector includes a transparent plate, and The display device, condenser lens, and retroreflector are located on one side of the reflector surface. (13)

[0127] According to the projection device in (12), where, The transparent panel includes the vehicle's windshield, and The display device, condenser lens, and retroreflector are installed in the vehicle. (14)

[0129] The projection device according to any one of (11) to (13) wherein the display device and the reflector are disposed on one surface side of the transparent plate, and the condenser lens and the retroreflector are disposed on the other surface side of the transparent plate. (15)

[0131] According to the projection device in (14), where, The transparent panel includes the vehicle's windshield, and The display device and reflector are located on the exterior of the vehicle, while the condenser lens and retroreflector are located inside the vehicle.

[0132] This application claims the benefit of Japanese priority patent application JP2024-031600, filed with the Japan Patent Office on March 1, 2024, the entire contents of which are incorporated herein by reference.

[0133] Those skilled in the art will understand that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents.

Claims

1. A projection device, comprising: Display device; A reflector reflects the light emitted from the display device to a predetermined direction; One or more condenser lenses; as well as An antireflector is positioned at the focal length of the condenser lens and reflects light incident via the mirror and the condenser lens back to the incident direction.

2. The projection device of claim 1, wherein, The condenser lens is positioned between the reflector and the retroreflector.

3. The projection device according to claim 1 further includes a pupil replication device, wherein, The body's axis is set as the X-axis, and the eye-to-eye direction is set as the Y-axis. The pupil replication device replicates the pupil conjugate point in the Y-axis direction, the X-axis direction, or both.

4. The projection apparatus according to claim 3, wherein, The pupil replication device is disposed between the display device and the reflector.

5. The projection apparatus according to claim 3, wherein, The pupil replication device includes a light guide panel, which includes a first half-reflector group and a second half-reflector group. The first half-reflector group includes a plurality of half-reflectors arranged in the X-axis direction, and the second half-reflector group includes a plurality of half-reflectors arranged in the Y-axis direction.

6. The projection device according to claim 1, wherein, The focusing lens includes a Fresnel lens.

7. The projection apparatus according to claim 1, wherein, The focusing lens includes a lens array.

8. The projection apparatus according to claim 1, wherein, The focusing lens includes a concave mirror.

9. The projection apparatus according to claim 1, wherein, The display device emits generally parallel light.

10. The projection apparatus according to claim 1, wherein, The display device includes an infinity-focusing projection lens.

11. The projection device according to claim 1, further comprising a transparent plate disposed in the optical path of light emitted from the display device.

12. The projection device according to claim 11, wherein, The reflector includes the transparent plate, and The display device, the condenser lens, and the retroreflector are disposed on one surface side of the reflector.

13. The projection device according to claim 12, wherein, The transparent panel includes the vehicle's windshield, and The display device, the condenser lens, and the retroreflector are disposed in the vehicle.

14. The projection apparatus according to claim 11, wherein, The display device and the reflector are disposed on one surface side of the transparent plate, and the condenser lens and the retroreflector are disposed on the other surface side of the transparent plate.

15. The projection device according to claim 14, wherein, The transparent panel includes the vehicle's windshield, and The display device and the reflector are disposed on the exterior of the vehicle, while the condenser lens and the retroreflector are disposed inside the vehicle.

Images