Optical member and image projection device

Abstract

To provide an optical member and an image projection device that can achieve weight reduction and improved design freedom.SOLUTION: An optical member (50) has: a first portion (51a) which is made of a light-transmitting material and has a first reflecting surface (52); a second portion (51b) which is arranged facing the first portion (51a), is made of a light-transmitting material, and has a second reflecting surface (53); a connecting portion (51g) which is formed integrally with the first portion (51a) and the second portion (51b) to connect them together; and a gap portion (54) which is provided between the first portion (51a) and the second portion (51b), and through which at least a part of the light passes.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an optical member and an image projection device, and more particularly to an optical member and an image projection device that project a projection image onto a display unit for displaying a virtual image. [Background technology]

[0002] Conventionally, dashboards that light up icons have been used as devices for displaying various types of information inside a vehicle. As the amount of information to be displayed increases, it has been proposed to embed an image display device in the dashboard or to configure the entire dashboard with an image display device.

[0003] However, since the instrument panel is located below the vehicle's windshield, the driver must move his or her eyes downward while driving in order to see the information displayed on the instrument panel, which is undesirable. Therefore, a head-up display (hereinafter referred to as HUD) has been proposed that projects an image onto the windshield so that the driver can read information when looking ahead of the vehicle (see, for example, Patent Documents 1 and 2).

[0004] In such a conventional image projection device, image light is projected from an image projection unit onto the windshield (display unit) of the vehicle, and the driver can visually recognize the image light reflected by the windshield superimposed on the background in front of the vehicle. It has also been proposed to project multiple image lights and form multiple virtual images at different distances from the windshield. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-119248 A [Patent Document 2] JP 2019-119262 A Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional image projection devices, multiple image lights emitted from a liquid crystal display device or the like are split using optical elements, and the image positions of virtual images are made different depending on the difference in the path of the split image light. Although a reflecting prism or the like may be used as an optical element for splitting the image light, a reflecting prism that is molded thick has problems in terms of moldability and weight reduction. In addition, because the refractive index of the material that constitutes the reflecting prism is higher than that of air, there are restrictions in terms of the path difference of the light propagating inside the reflecting prism and the angle of the reflecting surface, and there is a problem of low design freedom.

[0007] SUMMARY OF THE PRESENT DISCLOSURE The present invention has been made in consideration of the above-mentioned problems in the conventional art, and has an object to provide an optical member and an image projection device that can achieve weight reduction and improved design freedom. [Means for solving the problem]

[0008] In order to solve the above problems, the optical element of the present invention is characterized in having a first portion made of a material that transmits light and having a first reflecting surface, a second portion arranged opposite the first portion, made of a material that transmits light and having a second reflecting surface, a connecting portion formed integrally with the first portion and the second portion to connect them, and a gap portion provided between the first portion and the second portion and through which at least a portion of the light passes.

[0009] In such an optical element of the present invention, the first portion, the second portion, and the connecting portion are integrally formed from a light-transmitting material, and a gap is provided between the first portion and the second portion, thereby making it possible to reduce weight and improve design freedom.

[0010] In one aspect of the present invention, the gap is formed so that at least a portion thereof penetrates from the light incident side to the light exit side.

[0011] In addition, in one aspect of the present invention, the connecting portion is provided on a side of the gap portion.

[0012] In addition, in one aspect of the present invention, the connecting portion is provided on the light incident side of the gap portion.

[0013] In addition, in one aspect of the present invention, the connecting portion is provided on the light exit side of the gap portion.

[0014] In one aspect of the invention, the first portion has a refractive surface having a different thickness from the first reflecting surface, and the refractive surface faces the gap portion to refract the light.

[0015] In one aspect of the invention, the second portion has a refractive surface having a different thickness from the second reflecting surface, and the refractive surface faces the gap portion to refract the light.

[0016] In order to solve the above-mentioned problems, the image projection device of the present invention has an optical member according to any one of claims 1 to 5, and projects image light onto a display unit for displaying a virtual image, and is provided with an image irradiation unit which irradiates the image light, and a projection optical unit which irradiates the image light onto the display unit, wherein the image irradiation unit irradiates near image light from a near display area and far image light from a far display area, the far image light is reflected by the first reflecting surface and the second reflecting surface to reach the projection optical unit, and the near image light passes through the gap to reach the projection optical unit. Effect of the Invention

[0017] The present invention can provide an optical member and an image projection device that can achieve weight reduction and improved design freedom. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram illustrating projection of a virtual image using the image projection device 100 according to the first embodiment. [Diagram 2] FIG. 1 is a schematic cross-sectional view illustrating an overview of an image projection device 100 according to a first embodiment. [Diagram 3] 2 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 according to the first embodiment. FIG. [Figure 4] 2 is a schematic perspective view showing an example of the configuration of an optical member 50 according to the first embodiment. FIG. [Diagram 5] 11 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 according to a second embodiment. FIG. [Figure 6] 13 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 according to a third embodiment. FIG. [Figure 7] 13 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 according to a fourth embodiment. FIG. [Figure 8] 13 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 according to a fifth embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (First embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate.

[0020] FIG. 1 is a schematic diagram for explaining the projection of virtual images P1 and P2 using an image projection device 100 according to this embodiment. The dashed line in FIG. 1 indicates the optical path of a first image light L1, which will be described later, and the dashed line indicates the optical path of a second image light L2. As shown in FIG. 1, the first image light L1 and the second image light L2 projected from the image projection device 100 are reflected by a windshield (display unit) WS and irradiated to the driver's viewpoint position. The driver visually recognizes the virtual images P1 and P2 formed on the extension of the optical path on which the first image light L1 and the second image light L2 are incident. In this embodiment, an example is shown in which the image projection device 100 projects the first image light L1 and the second image light L2 to form two images P1 and P2, but the number of virtual images is not limited.

[0021] At this time, the trajectory of light reaching the viewpoint from the direction in which the virtual images P1 and P2 are viewed is taken as the reference ray. In other words, this reference ray can be considered to be substantially the same as the trajectory of light irradiated from the center of the effective area from which the light is emitted in the image irradiation unit 10 when it reaches the viewpoint. The actual image light is irradiated from the image irradiation unit 10 in a predetermined area, and the light beam spreads from each position on the display surface, and is condensed or expanded by the optical power of the reflecting surfaces of the first mirror 20 and the second mirror 30. Therefore, the reference ray shown in FIG. 1 does not indicate the path along which the irradiated light in the entire area of ​​the image irradiation unit 10 travels.

[0022] The windshield WS is a part provided in front of the driver's seat of the vehicle and transmits visible light. The windshield WS reflects the first image light L1 and the second image light L2 incident from the image projection device 100 toward the viewpoint direction on the inner surface of the vehicle and transmits light from the outside of the vehicle toward the viewpoint direction, and therefore corresponds to the display unit in the present invention. Here, an example is shown in which the windshield WS is used as the display unit, but a combiner may be prepared as a display unit separate from the windshield WS and may reflect light from the image projection device 100 toward the viewpoint direction. In addition, the display unit is not limited to being located in front of the vehicle, and may be located to the side or rear as long as it projects an image toward the viewpoint of the passenger.

[0023] The virtual images P1 and P2 are images that are displayed as if they were formed in space when the first image light L1 and the second image light L2 reflected by the windshield WS reach the viewpoint (eyebox) of the passenger. The positions at which the virtual images P1 and P2 are formed depend on the composite focal length of the projection optical unit included in the image projection device 100 and the windshield WS.

[0024] The viewpoint is the eye (eyebox) of the driver or passenger of the vehicle, and the driver or passenger visually recognizes the formed virtual images P1, P2 as the image light enters the eyebox and reaches the retina.

[0025] In the image projection device 100 of this embodiment, a far image displayed in the far display area of ​​the image projection unit 10 is irradiated as a first image light L1, and a near image displayed in the near display area is irradiated as a second image light L2. Examples of the far image displayed in the far display area include images calling attention and auxiliary information related to driving, such as emergency information. Examples of the near image displayed in the near display area include a speed and volume indicator, a driving direction guide, and the like.

[0026] FIG. 2 is a schematic cross-sectional view for explaining an overview of the image projection device 100 according to this embodiment. As shown in FIG. 2, the image projection device 100 includes an image projection unit 10, a first mirror 20, a second mirror 30, a housing 40, and an optical member 50. In the image projection device 100, each part is controlled using a control unit (not shown) connected to each part so as to be able to communicate information. The configuration of the control unit is not limited, but an example includes a CPU (Central Processing Unit) for performing information processing, a memory device, a recording medium, an information communication device, and the like. The control unit controls the operation of each part according to a predetermined program, and sends information including an image (image information) to the image projection unit 10.

[0027] The image irradiation unit 10 is a part that irradiates the first mirror 20 with light containing an image as image light based on image information from the control unit. In this embodiment, an example is shown in which two image lights displayed in two image display areas are irradiated onto the first mirror 20 as a first image light L1 and a second image light L2.

[0028] The first mirror 20 is an optical member that reflects the first image light L1 and the second image light L2 arriving from the image irradiation unit 10 toward the second mirror 30. In the example shown in Fig. 2, the first mirror 20 is a flat reflecting mirror, but a concave or convex reflecting mirror may be used. In addition, when the first mirror 20 is configured with a curved surface, it is not limited to a surface with a constant curvature, and a paraboloid of revolution, an ellipsoid, a free curved surface mirror, or the like may be used.

[0029] The second mirror 30 is an optical member that reflects the first image light L1 and the second image light L2 arriving from the first mirror 20 toward the windshield WS. In the example shown in Fig. 1, the second mirror 30 is a free-form mirror having an optically designed concave shape necessary for projecting the first image light L1 and the second image light L2 as virtual images P1, P2.

[0030] The reflecting surfaces of the first mirror 20 and the second mirror 30 are designed to expand the light diameter in the driver's viewpoint direction in order to project the first image light L1 and the second image light L2 as virtual images P1, P2 through the windshield WS. Here, the expansion of the light diameter in the viewpoint direction includes not only the case where the light diameter expands consistently after reflection, but also the case where the light diameter shrinks and expands after forming an image at an intermediate point. The combination of the first mirror 20 and the second mirror 30 has a function of projecting the first image light L1 and the second image light L2 through the windshield WS, and corresponds to the projection optical unit in the present invention.

[0031] The housing 40 is a container that constitutes the outer shape of the image projection device 100 and houses each component. The housing 40 is provided with a light exit port for emitting the first image light L1 and the second image light L2. An angle adjustment unit for adjusting the angle of the second mirror 30 may be provided in the housing 40 to adjust the irradiation angle of the first image light L1 and the second image light L2 projected onto the windshield WS and change the imaging height of the virtual images P1 and P2. The housing 40 may also be provided with an optical filter that cuts ultraviolet light and infrared light contained in light (external light) arriving from the outside.

[0032] The optical member 50 is made of a light-transmitting material, is disposed on the light emission side of the image irradiation unit 10, and is a part that repeatedly reflects the first image light L1 and transmits the second image light L2 to adjust the optical path difference between the first and second image light L1 and L2. The configuration of the optical member 50 will be described later. The material that constitutes the optical member 50 is not limited, but it is preferable to use a resin material or a glass material that has a high refractive index and a high light transmittance.

[0033] 2, the optical paths of the first image light L1 and the second image light L2 are depicted as a single straight arrow. However, the actual first image light L1 and the second image light L2 are displayed in a predetermined area in the image projection unit 10, and have a predetermined area in a direction perpendicular to the traveling direction, as shown by the range in the figure by the dashed line. Also, the first image light L1 and the second image light L2 may be reflected by the first mirror 20 and travel with their light diameters reduced, and may be intermediately imaged at an intermediate image position F (not shown) between the first mirror 20 and the second mirror 30.

[0034] Fig. 3 is a schematic cross-sectional view showing a configuration example of the optical member 50 in this embodiment. Of the light source unit, circuit board unit, and image display unit 11 that configure the image projection unit 10, Fig. 3 shows only the image display unit 11 on which the optical member 50 is arranged to be superimposed, and other parts are omitted from the illustration. Fig. 4 is a schematic perspective view showing a configuration example of the optical member 50 in this embodiment.

[0035] The image display unit 11 is a part that displays a projected image based on image information from the control unit. The specific configuration of the image display unit 11 is not limited, and for example, a conventionally known device such as a liquid crystal display device, an organic EL display device, or a light modulation element can be used. In the example shown in FIG. 3, the image display unit 11 includes a far display area 11a and a near display area 11b that display a near image and a far image, respectively. In FIG. 3, the first image light L1 irradiated from the far display area 11a is indicated by a solid arrow, and the second image light L2 irradiated from the near display area 11b is indicated by a dashed arrow.

[0036] The light source unit (not shown in FIG. 3) irradiates the image display unit 11 with irradiation light. In the example shown in FIG. 2, the light source unit is disposed on the rear side of the transmissive image display unit 11, and the irradiation light is transmitted through the image display unit 11. However, a reflective image display unit 11 may be used to irradiate the irradiation light from the display surface side. The specific configuration of the light source unit is not limited, and a light emitting diode (LED) or a laser light source may be used. In addition, when an organic EL display device is used as the image display unit 11, the light source unit and the image display unit 11 are integrally configured.

[0037] 3 and 4, the optical member 50 of this embodiment includes a first portion 51a, a second portion 51b, a light incident surface 51c, a refractive surface 51d, an inclined surface 51e, an inclined surface 51f, a connecting portion 51g, and an opening 51h. A reflecting surface 52 is provided on the inclined surface 51f, and a reflecting surface 53 is provided on the inclined surface 51e. A gap 54 is provided between the first portion 51a and the second portion 51b.

[0038] The first portion 51a is a part of the optical member 50 made of a light-transmitting material, and is a portion into which the first image light L1 is incident. The first portion 51a is integrally formed with the second portion 51b and the connecting portion 51g. The first portion 51a is disposed so as to overlap the far display area 11a of the image display unit 11, and the surface facing the far display area 11a is a light incident surface 51c. Parts of the surface of the first portion 51a form a refracting surface 51d and an inclined surface 51f.

[0039] The second portion 51b is a part of the optical member 50 made of a light-transmitting material, and is a part from which the first image light L1 is emitted. The second portion 51b is disposed opposite to the first portion 51a, and a part of the surface thereof forms an inclined surface 51e. In the example shown in Figs. 3 and 4, the second portion 51b is formed in a substantially plate-like shape.

[0040] The light incident surface 51c is a flat surface constituting a part of the surface of the first portion 51a, and is disposed opposite the far display area 11a of the image display unit 11. Although Fig. 3 shows an example in which the light incident surface 51c is disposed parallel to the far display area 11a, when the first image light L1 is refracted by the light incident surface 51c, the light incident surface 51c may be inclined at a predetermined angle with respect to the far display area 11a.

[0041] The refracting surface 51d is a surface that constitutes a part of the surface of the first portion 51a, and faces the gap 54. In Fig. 3, the refracting surface 51d is formed perpendicular to the image display unit 11, but it may be inclined at a predetermined angle with respect to the image display unit 11. In addition, although Fig. 3 shows an example in which the refracting surface 51d is provided near the boundary between the far display region 11a and the near display region 11b, the position is not limited as long as it is provided within a range that does not adversely affect the second image light L2.

[0042] The inclined surface 51e constitutes a part of the surface of the second portion 51b, and is a surface on which the reflective surface 53 is provided, and is provided at a predetermined angle with respect to the image display unit 11. In the example shown in Fig. 3, the surface of the second portion 51b opposite to the gap 54 is provided as the inclined surface 51e, but the surface facing the gap 54 may be provided as the inclined surface 51e and the reflective surface 53 may be provided.

[0043] The inclined surface 51f constitutes a part of the surface of the first portion 51a, is a surface on which the reflecting surface 52 is provided, and is provided at a predetermined angle with respect to the image display unit 11. Since the inclined surface 51f is provided at an angle with respect to the image display unit 11, the first portion 51a between the refracting surface 51d and the inclined surface 51f has a tapered shape with a different thickness in the lateral direction in the figure.

[0044] The connecting portion 51g is made of a light-transmitting material and is formed integrally with the first portion 51a and the second portion 51b. In Fig. 4, the connecting portion 51g is shown as a plate-shaped portion provided on the entire side of the gap portion 54, but the position and shape are not limited as long as the relative positional relationship between the first portion 51a and the second portion 51b can be maintained by forming the connecting portion 51g integrally with the first portion 51a and the second portion 51b.

[0045] The opening 51h is an opening formed in the optical member 50, and is provided opposite the near display region 11b. The opening 51h is surrounded by the first portion 51a, the second portion 51b, and the connecting portion 51g, and a region without the material constituting the optical member 50 is formed from the opening 51h toward the inside of the optical member 50, forming a gap portion 54.

[0046] The reflecting surface 52 is a portion provided on the inclined surface 51f to reflect light. The configuration of the reflecting surface 52 is not limited, and a sheet-like member that reflects light may be attached to the inclined surface 51f, or a metal material that reflects light may be evaporated onto the surface of the inclined surface 51f. The inclined surface 51f may be inclined at a greater angle than the critical angle, and light may be totally reflected at the interface between the inclined surface 51f and air due to the difference between the refractive index of the material that constitutes the first portion 51a and the refractive index of air. The reflecting surface 52 corresponds to the first reflecting surface in the present invention.

[0047] The reflecting surface 53 is a portion provided on the inclined surface 51e to reflect light. The configuration of the reflecting surface 53 is not limited, and a sheet-like member that reflects light may be attached to the inclined surface 51e, or a metal material that reflects light may be evaporated onto the surface of the inclined surface 51e. The inclined surface 51e may be inclined at a greater angle than the critical angle, and the light may be totally reflected at the interface between the inclined surface 51e and air due to the difference between the refractive index of the material that constitutes the first portion 51a and the refractive index of air. The reflecting surface 53 corresponds to the second reflecting surface in the present invention.

[0048] The gap 54 is provided between the first portion 51a and the second portion 51b, and is a region that is free of the material that constitutes the optical member 50. The gap 54 is provided at a position that overlaps with the near display region 11b. Although an example is shown in which the gap 54 is provided penetrating from the image display unit 11 side (light incident side) to the first mirror 20 side (light exit side) in Fig. 3 and Fig. 4, the material that constitutes the optical member 50 may be present on either the light incident side or the light exit side.

[0049] As shown in FIG. 3, the first image light L1 irradiated from the far display region 11a enters the first portion 51a from the light incident surface 51c and reaches the reflecting surface 52 provided on the inclined surface 51f. The first image light L1 is reflected by the reflecting surface 52 and turned back at the first portion 51a, and then travels from the refracting surface 51d across the gap 54 to reach the second portion 51b. At this time, the first image light L1 is refracted at the interface between the refracting surface 51d and the gap 54 depending on the incident angle of the first image light L1 with respect to the refracting surface 51d. The first image light L1 that has reached the second portion 51b is reflected again by the reflecting surface 53 provided on the inclined surface 51e and reaches the first mirror 20. The second image light L2 irradiated from the near display region 11b travels through the gap 54 to reach the first mirror 20.

[0050] 3, the second image light L2 is directly irradiated to the first mirror 20, whereas the first image light L1 is reflected by the reflecting surfaces 52 and 53 and irradiated to the first mirror 20. As a result, a difference in optical distance occurs between the second image light L2 and the first image light L1 until they reach the first mirror 20, which is the distance W in the longitudinal direction of the image display unit 11. Furthermore, on the reflecting surface of the first mirror 20, the first image light L1 and the second image light L2 reach different regions, and the paths of the first image light L1 and the second image light L2 reflected by the first mirror 20 also differ. Due to this difference in optical distance and path, the distance and the image formation position of the virtual images P1 and P2 from the windshield WS differ.

[0051] As described above, in the optical member 50 and image projector 100 of this embodiment, the first portion 51a, the second portion 51b, and the connecting portion 51g are integrally formed from a light-transmitting material, and the gap portion 54 is provided between the first portion 51a and the second portion 51b, thereby making it possible to reduce weight and improve design freedom. In addition, since the gap portion 54 is provided and the thickness of the optical member 50 can be reduced, deformation due to sink marks when molding the optical member 50 can be suppressed, and molding accuracy can be improved.

[0052] Furthermore, since the first portion 51a has the light incident surface 51c and the refraction surface 51d, the inclination angles of the light incident surface 51c and the refraction surface 51d with respect to the traveling direction of the first image light L1 can be appropriately set to refract the first image light L1. This improves the degree of freedom in designing the path of the first image light L1 that reaches the second portion 51b from the first portion 51a.

[0053] Furthermore, by providing an opening 51h and a void 54 at a position overlapping the near display region 11b, even if the first image light L1 is refracted at the refractive surface 51d and enters the image display unit 11 side in the second portion 51b, it is possible to prevent a portion of the light from being reflected or scattered by the material constituting the optical member 50 and becoming stray light.

[0054] Furthermore, by providing the connecting portion 51g on the side of the gap portion 54, the first portion 51a and the second portion 51b can be firmly integrated to maintain their relative positional relationship without having any optical effect on the first image light L1 and the second image light L2 traveling within the gap portion 54.

[0055] Second embodiment Next, a second embodiment of the present invention will be described with reference to FIG. 5. Descriptions of contents overlapping with the first embodiment will be omitted. FIG. 5 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 in this embodiment. This embodiment differs from the first embodiment in that the image display unit 11 irradiates only one image light. As shown in FIG. 5, in this embodiment, a first portion 51a of the optical member 50 is arranged to overlap the image display unit 11, and the image display unit 11 is not provided in the gap portion 54.

[0056] 5, image light emitted from the image display unit 11 is incident on the first portion 51a from the light incident surface 51c, and reaches the reflecting surface 52 provided on the inclined surface 51f. The image light is reflected by the reflecting surface 52, turned back at the first portion 51a, and reaches the second portion 51b through the refracting surface 51d, crossing the gap 54. At this time, the image light is refracted at the interface between the refracting surface 51d and the gap 54, depending on the incident angle of the image light with respect to the refracting surface 51d. The image light that has reached the second portion 51b is reflected again by the reflecting surface 53 provided on the inclined surface 51e, and reaches the first mirror 20.

[0057] In the optical element 50 and image projection device 100 of this embodiment, the first portion 51a, the second portion 51b, and the connecting portion 51g are integrally formed from a light-transmitting material, and a gap portion 54 is provided between the first portion 51a and the second portion 51b, thereby making it possible to reduce weight and improve design freedom.

[0058] Third embodiment Next, a third embodiment of the present invention will be described with reference to Fig. 6. Descriptions of contents overlapping with the first embodiment will be omitted. Fig. 6 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 in this embodiment. This embodiment differs from the second embodiment in that a connecting portion 51i is provided on the light emission side of the cavity portion 54.

[0059] The connecting portion 51i is made of a light-transmitting material and is formed integrally with the first portion 51a and the second portion 51b. Although Fig. 6 shows only an example in which the connecting portion 51i is provided on the light emission side of the cavity 54, the connecting portion 51i may be used together with the connecting portion 51g provided on the side of the cavity 54 shown in the first embodiment.

[0060] In the example shown in FIG. 6, image light emitted from the image display unit 11 enters the first portion 51a from the light incident surface 51c and reaches the reflecting surface 52 provided on the inclined surface 51f. The image light is reflected by the reflecting surface 52, turned back at the first portion 51a, and reaches the second portion 51b through the refracting surface 51d and the gap 54. At this time, the image light is refracted at the interface between the refracting surface 51d and the gap 54 depending on the incident angle of the image light with respect to the refracting surface 51d. The image light that reaches the second portion 51b is reflected again by the reflecting surface 53 provided on the inclined surface 51e, and reaches the first mirror 20 after passing through the connecting portion 51i.

[0061] In the optical member 50 and image projection device 100 of this embodiment, the first portion 51a, the second portion 51b, and the connecting portion 51i are integrally formed from a light-transmitting material, and the gap portion 54 is provided between the first portion 51a and the second portion 51b, so that it is possible to reduce weight and improve design freedom. Furthermore, since the connecting portion 51i is provided on the light exit side of the gap portion 54, even if the image light is refracted at the refracting surface 51d and enters the image display unit 11 side of the second portion 51b, it is possible to suppress a part of the light being reflected or scattered by the material constituting the optical member 50 and becoming stray light.

[0062] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. 7. Descriptions of contents overlapping with the first embodiment will be omitted. FIG. 7 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 in this embodiment. This embodiment differs from the second embodiment in that a connecting portion 51j is provided on the light incident side of a gap portion 54.

[0063] The connecting portion 51j is made of a light-transmitting material and is formed integrally with the first portion 51a and the second portion 51b. Although Fig. 7 shows only an example in which the connecting portion 51j is provided on the light incident side of the cavity 54, the connecting portion 51j may be used together with the connecting portion 51g provided on the side of the cavity 54 shown in the first embodiment.

[0064] 7, image light emitted from the image display unit 11 enters the first portion 51a from the light incident surface 51c and reaches the reflecting surface 52 provided on the inclined surface 51f. The image light is reflected by the reflecting surface 52 and turned back at the first portion 51a, and reaches the second portion 51b through the refracting surface 51d and across the gap 54. At this time, the image light is refracted at the interface between the refracting surface 51d and the gap 54 depending on the incident angle of the image light with respect to the refracting surface 51d. The image light that has reached the second portion 51b is reflected again by the reflecting surface 53 provided on the inclined surface 51e and reaches the first mirror 20.

[0065] In the optical element 50 and image projection device 100 of this embodiment, the first portion 51a, the second portion 51b, and the connecting portion 51j are integrally formed from a light-transmitting material, and a gap portion 54 is provided between the first portion 51a and the second portion 51b, thereby making it possible to reduce weight and improve design freedom.

[0066] Fifth embodiment Next, a fifth embodiment of the present invention will be described with reference to Fig. 8. Descriptions of contents overlapping with the first embodiment will be omitted. Fig. 8 is a schematic cross-sectional view showing an example of the configuration of an optical member 50 in this embodiment. This embodiment differs from the second embodiment in that a refractive surface 51d is provided in the second portion 51b.

[0067] 8, in this embodiment, the refraction surface 51d is provided in the second portion 51b, and therefore the second portion 51b between the refraction surface 51d and the inclined surface 51e has a tapered shape with a different thickness in the horizontal direction in the figure. Also, the first portion 51a is formed in a substantially plate shape. Here, as in the second embodiment, the connection portion 51g is provided on the side of the gap 54, but as in the third embodiment, the connection portion 51i may be provided on the light exit side, and as in the fourth embodiment, the connection portion 51j may be provided on the light entrance side.

[0068] In the example shown in FIG. 8, image light emitted from the image display unit 11 enters the first portion 51a and reaches the reflecting surface 52 provided on the inclined surface 51f. The image light is reflected by the reflecting surface 52, turned back at the first portion 51a, crosses the gap 54, and enters the second portion 51b from the refracting surface 51d. At this time, the image light is refracted at the interface between the refracting surface 51d and the gap 54 depending on the incident angle of the image light with respect to the refracting surface 51d. The image light that has reached the second portion 51b is reflected again by the reflecting surface 53 provided on the inclined surface 51e, exits from the light exit surface 51k, and reaches the first mirror 20.

[0069] In the optical element 50 and image projection device 100 of this embodiment, the first portion 51a, the second portion 51b, and the connecting portion 51g are integrally formed from a light-transmitting material, and a gap portion 54 is provided between the first portion 51a and the second portion 51b, thereby making it possible to reduce weight and improve design freedom.

[0070] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0071] 100...Image projection device 10...Image irradiation unit 11...Screen display section 11a…Far display area 11b…Near display area 20…1st mirror 30…2nd mirror 40…Housing 50...Optical components 51a…first part 51b…Second part 51c...Light incidence surface 51d…Refractive surface 51e,51f…Slanted surface 51g, 51i, 51j…Connection part 51h…Opening 51k...Light exit surface 52,53…Reflective surface 54…Gap

Claims

1. a first portion made of a light-transmitting material and having a first reflective surface; a second portion disposed opposite the first portion, the second portion being made of a material that transmits the light, and having a second reflecting surface; a connecting portion formed integrally with the first portion and the second portion to connect the first portion and the second portion; an optical member having a gap provided between the first portion and the second portion, through which at least a portion of the light passes.

2. The optical member according to claim 1 , The optical member is characterized in that at least a portion of the void portion is formed to penetrate from the light incident side to the light exit side.

3. The optical member according to claim 1 , The optical member according to claim 1, wherein the connecting portion is provided on a side of the gap portion.

4. The optical member according to claim 1 , The optical member according to claim 1, wherein the connecting portion is provided on a side of the gap where the light is incident.

5. The optical member according to claim 1 , The optical member according to claim 1, wherein the connecting portion is provided on the light exit side of the gap portion.

6. The optical member according to claim 1 , The optical member according to claim 1, wherein the first portion has a refractive surface having a different thickness from the first reflecting surface, the refractive surface facing the gap portion to refract the light.

7. The optical member according to claim 1 , The optical member according to claim 1, wherein the second portion has a refractive surface having a different thickness from the second reflecting surface, the refractive surface facing the gap portion to refract the light.

8. The optical member according to any one of claims 1 to 7, An image projection device that projects image light onto a display unit for displaying a virtual image, an image irradiating unit that irradiates the image light; a projection optical unit that irradiates the image light onto the display unit, the image irradiating unit irradiates near image light from a near display region and irradiates far image light from a far display region; the distant image light is reflected by the first reflecting surface and the second reflecting surface to reach the projection optical unit, The near image light passes through the gap and reaches the projection optical unit.

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