WO2024117058A1

WO2024117058A1 - Image irradiation device

Info

Publication number: WO2024117058A1
Application number: PCT/JP2023/042288
Authority: WO
Inventors: 雅大遠藤
Original assignee: 株式会社小糸製作所
Priority date: 2022-12-02
Filing date: 2023-11-27
Publication date: 2024-06-06
Also published as: JP2024080344A

Abstract

The present invention makes it possible to, in an image irradiation device configured to project a display image onto an image display part, prevent a sense of incongruity caused by reflection of unnecessary images in the image display part from being given to a user. This image irradiation device is configured such that an image generation unit 20 for generating a display image PIC, and first and second reflecting mirrors 30, 40 for sequentially reflecting emitted light from the image generation unit 20 toward a display region 102A of a front window 102 as an image display part are housed in a housing 50. The image irradiation device is further configured such that in an internal space 12 of the housing 50, an internal cover 70 that covers the periphery of the image generation unit 20 is disposed within a range in which the emitted light from the image generation unit 20 is not prevented from being reflected by the first reflecting mirror 30 and entering the second reflecting mirror 40. Consequently, the peripheral structure of the image generation unit 20, the first reflecting mirror 30, and the like are prevented from being reflected in the display region 102A by the reflecting function of the second reflecting mirror 40.

Description

Image projection device

The present invention relates to an image projection device configured to project a display image onto an image display unit.

Conventionally, there are known in-vehicle image projection devices that are arranged in the vehicle interior and project a display image onto an image display section, such as the front window (i.e., windshield) or a translucent plate arranged on the inside of the vehicle interior.

Patent Document 1 describes such an image projection device as comprising an image generating unit that generates an image for display, a reflector that reflects the light emitted from the image generating unit toward the image display section, and a housing that contains the image generating unit and the reflector.

WO 2020/110580

In such image projection devices, the reflecting function of the reflector can cause the surrounding structure of the image generating unit to be reflected on the image display unit.

If an unnecessary image other than the intended display image is reflected on the image display unit in this way, it will give the user, the driver, a strange feeling.

Similar problems can occur with image projection devices other than those mounted on vehicles.

The present invention has been made in consideration of these circumstances, and aims to provide an image projection device that is configured to project a display image onto an image display section, and that can prevent the user from feeling uncomfortable due to unwanted images being reflected onto the image display section.

The present invention aims to achieve the above objective by placing a specified internal cover in the internal space of the housing.

That is, the image projection device according to the present invention is
In an image projection device configured to project a display image on an image display unit,
the display device includes an image generating unit that generates an image for display, a reflecting mirror that reflects light emitted from the image generating unit toward the image display unit, and a housing that accommodates the image generating unit and the reflecting mirror,
The present invention is characterized in that an internal cover that covers the periphery of the image generating unit is disposed in the internal space of the housing within a range that does not prevent light from being incident from the image generating unit to the reflecting mirror.

The above-mentioned "image projection device" is not particularly limited in its specific use, so long as it is configured to project a display image on the image display unit, and can be used, for example, as an in-vehicle head-up display.

The "image display unit" is not particularly limited in its specific configuration, so long as it is configured to project a display image, and for example, a translucent plate placed on the front window of the vehicle or on the inside of the passenger compartment can be used.

The "image generating unit" does not necessarily have to be entirely contained within the internal space of the housing, so long as at least a portion of it faces the internal space of the housing.

The specific configuration of the "reflecting mirror" is not particularly limited as long as it is configured to reflect the light emitted from the image generating unit toward the image display unit.

The above-mentioned "internal cover" is not particularly limited in its specific shape or arrangement, so long as it is configured to cover the periphery of the image generating unit to an extent that does not prevent light from being incident from the image generating unit to the reflector, and there is also no particular limitation on the specific extent to which it covers the structures in the internal space of the housing.

The image projection device of the present invention is configured so that an image generation unit that generates an image for display and a reflector that reflects the light emitted from this image generation unit towards the image display section are contained in a housing, and an internal cover that covers the periphery of the image generation unit within an area that does not prevent the light from being incident on the reflector from the image generation unit is disposed in the internal space of the housing, so that the reflecting function of the reflector can prevent the surrounding structure of the image generation unit from being reflected in the image display section. In other words, it can prevent the user from feeling uncomfortable due to unnecessary images other than the original display image being reflected in the image display section.

In this way, according to the present invention, in an image projection device configured to project a display image onto an image display section, it is possible to prevent the user from feeling uncomfortable due to unnecessary images being reflected onto the image display section.

In the above configuration, if a primary reflector that reflects the light emitted from the image generating unit toward the reflector is further arranged in the internal space of the housing, it becomes possible to allow for flexibility in the arrangement of the image generating unit. On the other hand, when such a configuration is adopted, the peripheral structure of the image generating unit and the primary reflector, etc., tend to be projected onto the image display unit by the reflector, so it is particularly effective to adopt the configuration of the present invention.

In the above configuration, if the reflector is configured as a concave mirror with a horizontal cross-sectional shape that is a concave curve, and the edge portion of the inner cover facing the reflector is formed to extend in a convex curve along the shape of the bottom edge of the reflector, the following effects can be obtained.

In other words, when the reflecting mirror is configured as a concave mirror having a concavely curved horizontal cross-sectional shape, it is possible to efficiently project a horizontally long display image onto the image display section using the light emitted from the image generating unit. On the other hand, the image generating unit and its surrounding structure will end up being projected onto the image display section in an enlarged state, so it is particularly effective to adopt the configuration of the present invention.

In this case, by configuring the inner cover so that its edge on the reflector side extends in a convex curve along the shape of the bottom edge of the reflector, the appearance of the structure in the inner space of the housing is not marred even when it is projected on the image display unit in an enlarged state.

In the above configuration, if the reflector is further supported so as to be rotatable about an axis extending in the left-right direction relative to the housing, it becomes possible to adjust the orientation of the reflector, thereby enabling the display image to be projected at the appropriate position on the image display unit. In this case, if the first housing and the second housing are assembled as the housing, a mounting portion for mounting the shaft of the reflector is formed on the first housing, and an abutment portion that abuts against the shaft mounted on this mounting portion is formed on the internal cover, the following effects can be obtained.

In other words, it is possible to adjust the orientation of the reflector without the need to provide a dedicated bracket or other device to rotatably support the reflector. In this case, since the contact portion is formed on the inner cover rather than the second housing, the degree of freedom in its shape can be increased, which makes it easy to reliably position the reflector.

In the above configuration, if a lever member is fixed to the shaft of the reflector, extending in a direction intersecting the axial direction of the reflector, and this lever member is connected to an actuator for rotating the reflector around the axis, it becomes possible to rotate the reflector with the minimum number of members required.

In this case, if the mounting portion of the first housing and/or the abutment portion of the inner cover are configured as ribs with arc-shaped recesses, and the lever member is configured to have an insertion hole for inserting the tip of the mounting portion and/or the abutment portion, and the reflector is configured to be positioned in the axial direction by engagement between the tip of the mounting portion and/or the abutment portion and the inner surface of the insertion hole, it becomes easy to project the display image in the correct position not only in the vertical direction but also in the horizontal direction. Moreover, this can be achieved without requiring a large amount of space in the horizontal direction.

FIG. 1 is a side cross-sectional view showing an image projection device according to an embodiment of the present invention mounted on a vehicle. FIG. 2 is a view taken in the direction of the arrow II in FIG. Detailed view of part III in Figure 1 FIG. 2 is a plan view showing the image projection device with the second housing removed; 5 is a cross-sectional view taken along line V-V of FIG. VI-VI line cross section of Figure 4 Cross-sectional view of line VII-VII in FIG. FIG. 4 is a perspective view showing the state of assembly of the image projection device. FIG. 8 is a view similar to FIG. 7, showing a first modification of the embodiment; FIG. 5 is a view similar to FIG. 4, showing a second modification of the embodiment;

The following describes an embodiment of the present invention with reference to the drawings.

FIG. 1 is a side cross-sectional view showing an image projection device 10 according to this embodiment mounted on a vehicle 100. FIG. 2 is a view taken in the direction of the arrow II in FIG. 1.

In Figures 1 and 2, the direction indicated by X is the "forward" direction of the image projection device 10 (also the "forward" direction of the vehicle), the direction indicated by Y is the "leftward" direction perpendicular to the "forward" direction, and the direction indicated by Z is the "upward" direction. This is the same in other figures besides Figures 1 and 2.

As shown in Figures 1 and 2, the image projection device 10 according to this embodiment is an in-vehicle head-up display, and is configured to project a display image PIC as a virtual image on a display area 102A of a front window 102 serving as an image display unit when placed in the passenger compartment of a vehicle 100.

The optical path R shown in FIG. 1 is the optical path through which the driver 2 visually recognizes the display image PIC projected on the display area 102A of the front window 102 by the image projection device 10.

The display area 102A is positioned in the lower area of the windshield 102 and in front of the steering wheel 104, so that the driver 2 of the vehicle 100 can easily visually recognize it. Note that FIG. 2 shows a specific example of the display image PIC in which the vehicle speed (50 Km/h) is displayed together with an arrow pointing to the left.

The image projection device 10 is positioned in front of the steering wheel 104 and near the bottom of the windshield 102.

As shown in FIG. 1, the image projection device 10 includes an image generation unit 20 that generates an image that is the basis of the display image PIC, first and

second reflectors

30, 40 that sequentially reflect the light emitted from the image generation unit 20 toward the display area 102A of the front window 102, an inner cover 70 that covers the periphery of the image generation unit 20, a housing 50 that contains these, and a translucent cover 60 attached to the housing 50.

The image generating unit 20, the first and

second reflectors

30, 40 and the inner cover 70 are supported by a housing 50 (described below).

The housing 50 is configured with a first housing 52 that is open upward and a second housing 54 attached to it.

FIG. 3 is a detailed view of part III in FIG. 1. FIG. 4 is a plan view showing the image projection device 10 with the second housing 54 removed, and FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4.

As shown in Figures 3 to 5, the second housing 54 has an outer peripheral flange portion 54b, and is assembled to the first housing 52 with this outer peripheral flange portion 54b abutting against the upper end opening 52a of the first housing 52.

The first and

second housings

52, 54 are both made of opaque resin moldings. The second housing 54 has an opening 54a formed therein to allow the reflected light from the second reflector 40 to pass through toward the display area 102A.

The light-transmitting cover 60 is composed of a colorless, transparent resin panel. This light-transmitting cover 60 is positioned so as to cover the opening 54a of the second housing 54, in a state in which it is curved downward and tilted slightly upward toward the rear. This light-transmitting cover 60 allows the reflected light from the second reflector 40 to enter the display area 102A, while ensuring that the internal space 12 of the housing 50 is dust-proof.

As shown in Figures 4 and 5, the first and

second reflectors

30, 40 have

reflective surfaces

30a, 40a that are symmetrical in shape, and the image generating unit 20 is located at the center in the left-right direction.

The image generating unit 20 is equipped with a liquid crystal panel 22 having a rectangular outer shape, and is arranged so that the liquid crystal panel 22 faces the internal space 12 of the housing 50. Specifically, the image generating unit 20 is supported by the lower wall portion 52b of the first housing 52 with the liquid crystal panel 22 arranged so that its longitudinal direction extends in the left-right direction (i.e., the vehicle width direction) and with the liquid crystal panel 22 facing diagonally upward and rearward.

The image generating unit 20 is configured to generate an image that is the basis of the display image PIC on the liquid crystal panel 22 by illuminating the liquid crystal panel 22 with backlight from its rear side.

The lower wall portion 52b of the first housing 52 is formed with a unit mounting portion 52d for mounting the image generating unit 20. This unit mounting portion 52d is formed with a rectangular opening 52e that is slightly larger than the external shape of the liquid crystal panel 22.

The image generating unit 20 is fixed to the bottom wall portion 52b of the first housing 52 by screwing or the like, with the liquid crystal panel 22 positioned so that it fits into the opening 52e of the unit mounting portion 52d.

The first reflector 30 is positioned diagonally above and behind the image generating unit 20 and is configured to reflect the light emitted from the image generating unit 20 forward.

The first reflector 30 is configured as a saddle-shaped reflector in which the surface shape of its reflecting surface 30a is a saddle-shaped curved surface. The reflecting surface 30a of this first reflector 30 has a roughly rectangular outer shape extending in the left-right direction when viewed from the front of the vehicle. Specifically, the horizontal cross-sectional shape of this reflecting surface 30a is configured as a convex curve, and the vertical cross-sectional shape is configured as a concave curve.

The first reflector 30 has flanges 32 formed on both the left and right ends of its reflecting surface 30a, and is fixed to the first housing 52 at these pair of left and right flanges 32.

Specifically, each flange portion 32 has a side wall portion 32A formed to extend rearward along a vertical plane from the side end of the reflecting surface 30a, and a stepped portion 32B formed to extend laterally from the outer surface of the side wall portion 32A. The first reflecting mirror 30 is fixed to a pair of left and right columnar protrusions 52f formed on the bottom wall portion 52b of the first housing 52 by screws 34, with the pair of left and right stepped portions 32B being positioned and fastened by pins 52g.

As shown in Figures 3 to 5, the second reflector 40 is disposed in front of the first reflector 30. This second reflector 40 is configured to reflect the irradiation light from the image generating unit 20 that is reflected by the first reflector 30 upward.

The second reflector 40 is a concave mirror, and the surface shape of its reflecting surface 40a is composed of a roughly spherical concave curved surface. The reflecting surface 40a of the second reflector 40 has a rectangular outer shape extending in the left-right direction when viewed from the front of the vehicle. In this regard, the reflecting surface 40a of the second reflector 40 is formed to be larger in size than the reflecting surface 30a of the first reflector 30, and is formed to have a larger aspect ratio than the reflecting surface 30a of the first reflector 30.

In this way, the reflective surface 40a of the second reflector 40 is curved significantly in the direction of the image that is desired to be viewed by the driver 2, and is formed with a larger aspect ratio than the reflective surface 30a of the first reflector 30. However, since the first reflector 30 is configured as a saddle-shaped reflector, the reflected light from its reflective surface 30a spreads less in the vertical direction and more in the horizontal direction, which allows it to efficiently enter the reflective surface 40a of the second reflector 40.

The lower wall portion 52b of the first housing 52 is formed at a higher position than the portion where the unit mounting portion 52d is formed and the portion located below the reflecting

surfaces

30a, 40a of the first and

second reflectors

30, 40.

As shown in FIG. 3, the second housing 54 is formed with a light-shielding piece 54c that covers the peripheral area of the reflecting surface 30a of the first reflector 30. This light-shielding piece 54c is formed in a plate shape that extends diagonally downward and forward from the rear edge of the opening 54a in the second housing 54.

In the image projection device 10, sunlight S entering the vehicle interior through the front window 102 may enter the internal space 12 of the housing 50 through the translucent cover 60, but the light-shielding action of the light-shielding piece 54c prevents this sunlight S from reaching the peripheral area of the reflecting surface 30a of the first reflector 30.

As a result, even if a deposition film or the like adheres to the peripheral area of the reflection surface 30a during surface treatment to form the reflection surface 30a of the first reflecting mirror 30, sunlight S that reaches this peripheral area is prevented from being reflected by the deposition film or the like and becoming stray light.

As shown in Figures 4 and 5, the second reflector 40 is supported by the first housing 52 so as to be rotatable about an axis Ax that extends in the left-right direction near the front of the second reflector 40. This allows the second reflector 40 to adjust its angle so that the reflected light from the first reflector 30 is accurately incident on the display area 102A of the front window 102.

To achieve this, a pair of left and right vertical flanges 42 extending forward along a vertical plane are formed on both left and right ends of the rear side of the reflecting surface 40a of the second reflecting mirror 40. These pair of left and right vertical flanges 42 are then formed with first and

second shafts

44A, 44B extending in both left and right directions (i.e., directions away from the reflecting surface 40a) on the axis Ax.

The first and

second shaft portions

44A, 44B are both formed in a cylindrical shape. In this case, the second shaft portion 44B located on the right side (left side when viewed from the front of the device) is formed with a smaller outer diameter than the first shaft portion 44A located on the left side, but its tip portion is formed with the same outer diameter as the first shaft portion 44A.

The base end 46a of the lever member 46, which extends rearward, is fixed to the tip surface of the second shaft portion 44B. The base end 46a of the lever member 46 is formed to extend cylindrically and coaxially with the second shaft portion 44B, and its outer diameter is set to the same value as the tip end of the second shaft portion 44B.

The tip 46b of the lever member 46 is connected to the output shaft 48a of an actuator 48 for rotating the second reflector 40 around the axis Ax.

The actuator 48 is fixed to the lower wall portion 52b of the first housing 52 on the lower side. The output shaft 48a of this actuator 48 is formed to extend upward into the internal space 12 of the housing 50, and is configured to be movable in the vertical direction.

The first and

second shaft portions

44A, 44B are placed on a pair of left and right mounting

portions

52h, 52j formed on the lower wall portion 52b of the first housing 52.

The left mounting portion 52h is formed to extend in the direction of the axis Ax from the inner surface of the peripheral wall portion 52c of the first housing 52. The upper surface of this mounting portion 52h is formed in a roughly U-shape, and its lower end portion is configured as a semi-cylindrical surface having an inner diameter roughly the same as the outer diameter of the first shaft portion 44A.

The right-side mounting portion 52j is formed at a position away from the peripheral wall portion 52c of the first housing 52 (specifically, the connection position between the base end portion 46a and the arm portion 46c of the lever member 46). This mounting portion 52j is formed as a rib that protrudes upward along a vertical plane extending in the front-to-rear direction of the device from the bottom wall portion 52b of the first housing 52. The upper surface of this mounting portion 52j is formed in a roughly U-shape, and its lower end portion is composed of a semi-cylindrical surface with an inner diameter roughly the same as the outer diameter of the base end portion 46a of the lever member 46.

In FIG. 3, the state when the second reflecting mirror 40 rotates forward around the axis Ax is shown by a two-dot chain line, and the state when the second reflecting mirror 40 rotates rearward around the axis Ax is shown by a dashed line.

As shown in Figures 3 to 5, the internal cover 70 is positioned to cover the periphery of the image generating unit 20 to an extent that does not prevent the light emitted from the image generating unit 20 from being reflected by the first reflecting mirror 30 and entering the second reflecting mirror 40.

The inner cover 70 is made of an opaque resin molded product and includes a cover body 72 located below the first and

second reflectors

30, 40, and a pair of

brackets

74A, 74B located on both the left and right sides of the first and

second reflectors

30, 40.

The cover body 72 is formed so as to extend diagonally downward and forward like a flat plate. A cylindrical opening 72a extending downward is formed at the rear of the cover body 72. The cylindrical opening 72a is formed in a tapered shape, and its lower opening end 72a1 is formed so as to surround the liquid crystal panel 22 of the image generating unit 20 near the opening 52e of the first housing 52.

The cover body 72 is formed so that its rear edge 72b is located near the bottom edge of the first reflector 30, and its front edge 72c is located near the bottom edge of the second reflector 40. In this case, the front edge 72c of the cover body 72 is formed so that it extends in a convex curve along the bottom edge shape, in correspondence with the reflective surface 40a of the second reflector 40 having a concave curved horizontal cross-sectional shape.

The pair of left and

right bracket parts

74A, 74B are formed with a step up from the cover body part 72 and are formed to extend further forward than the cover body part 72. The pair of left and

right bracket parts

74A, 74B have their front ends formed with a step up further than the other general parts.

The cover body 72 is fixed to the first housing 52 at a pair of left and

right bracket parts

74A, 74B. At this time, the cover body 72 is fixed by screws at the front ends of the pair of left and

right bracket parts

74A, 74B, and is fixed by a lance at the rear ends.

Specifically, the above-mentioned screw fastening is performed by fastening screws 76 into a pair of left and right bosses 52bA, 52bB formed at the front end position of the lower wall portion 52b of the first housing 52 through screw insertion holes 74a formed at the front ends of a pair of left and

right bracket portions

74A, 74B.

The lance is fixed by inserting downward lances 74b formed at the rear ends of the pair of left and

right bracket portions

74A, 74B into and engaging with a pair of left and right lance engagement holes 52k formed at the front end position of the lower wall portion 52b of the first housing 52.

As shown in FIG. 4, the front end of the left bracket portion 74A is formed with an abutment portion 74Ac for abutting from above against the first shaft portion 44A placed on the mounting portion 52h of the first housing 52 to position the second reflector 40. In addition, the front end of the right bracket portion 74B is formed with an abutment portion 74Bc for abutting from above against the base end portion 46a of the lever member 46 placed on the mounting portion 52j of the first housing 52 to position the second reflector 40.

Each abutment portion 74Ac, 74Bc is formed as a rib that protrudes downward from the outer peripheral flange portion 54b of the second housing 54, and a semi-cylindrical recess is formed on its lower end surface, with an inner diameter that is approximately the same as the outer diameter of each of the first shaft portion 44A and the base end portion 46a of the lever member 46.

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4, and FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 4.

As shown in FIG. 6, the arm portion 46c of the lever member 46 has an H-shaped cross section. A rectangular insertion hole 46d that is long in the front-to-rear direction of the device is formed in the front end of the horizontal surface of the arm portion 46c (i.e., the area near the base end portion 46a). When the base end portion 46a of the lever member 46 is placed on the mounting portion 52j of the first housing 52, the rear end portion 52j1 of the rib-shaped mounting portion 52j is inserted through this insertion hole 46d.

As shown in FIG. 6, the rear end 52j1 of the mounting portion 52j is formed slightly away from the base end 46a of the lever member 46, which allows for smooth insertion into the insertion hole 46d.

The second reflector 40 is positioned in the left-right direction (i.e., in the direction of the axis Ax) by the engagement between the inner surface of the insertion hole 46d of the lever member 46 and the rear end portion 52j1 of the mounting portion 52j.

As shown in Figure 7, the mounting portion 52j is tapered upward, but the rear end 52j1 has a constant left-right width and its most distal surface is formed into a convex curved shape. This makes it easy to insert the rear end 52j1 into the insertion hole 46d, and even if the arm portion 46c is displaced up or down due to the rotation of the lever member 46 after insertion, the engagement between the inner surface of the insertion hole 46d of the lever member 46 and the rear end 52j1 of the mounting portion 52j is maintained with high precision.

Figure 8 is a perspective view showing the assembly of the image projection device 10.

As shown in FIG. 8, the image projection device 10 is assembled by sequentially attaching the second reflector 40, the inner cover 70, and the second housing 54 to the first housing 52 from above.

In FIG. 8, the first housing 52 is shown with the first reflector 30 and the actuator 48 already attached, the second reflector 40 is shown with the lever member 46 already attached, and the second housing 54 is shown with the translucent cover 60 already attached.

The second reflector 40 is attached to the first housing 52 by placing the first shaft portion 44A of the second reflector 40 on the mounting portion 52h of the first housing 52 and the base end portion 46a of the lever member 46 on the mounting portion 52j of the first housing 52. At that time, the tip portion 46b of the lever member 46 is connected to the output shaft 48a of the actuator 48.

As described above, the inner cover 70 is attached to the first housing 52 by screwing the front ends of the pair of left and

right bracket parts

74A, 74B of the cover body part 72 and by lance fixing the rear ends of the

bracket parts

74A, 74B.

The second housing 54 is attached to the first housing 52 by lance engagement at multiple locations. To achieve this, the second housing 54 is formed with downward lances 54d at multiple locations on its outer circumferential flange portion 54b, and the first housing 52 is formed with lance engagement portions 52m that open in the vertical direction at positions corresponding to the multiple lances 54d. Then, when the outer circumferential flange portion 54b of the second housing 54 abuts against the upper end opening 52a of the first housing 52, each lance 54d is inserted into and engages with each lance engagement portion 52m, thereby fixing the second housing 54 to the first housing 52.

Next, the operation of this embodiment will be explained.

The image projection device 10 according to this embodiment is configured such that an image generating unit 20 that generates a display image PIC and first and

second reflectors

30, 40 that sequentially reflect the light emitted from the image generating unit 20 toward the display area 102A of the front window 102 as an image display unit are housed in a housing 50. In the internal space 12 of the housing 50, an internal cover 70 is arranged that covers the periphery of the image generating unit 20 within a range that does not prevent the light emitted from the image generating unit 20 from being reflected by the first reflector 30 (primary reflector) and entering the second reflector 40 (reflector), so that the reflection function of the second reflector 40 can prevent the peripheral structure of the image generating unit 20 from being reflected in the display area 102A. In other words, it can prevent the user from feeling uncomfortable due to the reflection of unnecessary images other than the original display image PIC in the display area 102A.

In this way, according to this embodiment, in an image projection device 10 configured to project a display image PIC onto the display area 102A of the front window 102, it is possible to prevent the user from feeling uncomfortable due to an unnecessary image being reflected onto the display area 102A.

The image projection device 10 according to this embodiment is configured such that the first reflector 30 is disposed in the internal space 12 of the housing 50 as a primary reflector that reflects the light emitted from the image generating unit 20 toward the second reflector 40, thereby improving the degree of freedom in the placement of the image generating unit 20. On the other hand, when this is adopted, the peripheral structure of the image generating unit 20 and the first reflector 30, etc., tend to be reflected in the display area 102A by the second reflector 40, so it is particularly effective to adopt the configuration of this embodiment.

Furthermore, in this embodiment, the second reflector 40 is configured as a concave mirror having a horizontal cross-sectional shape that is a concave curve, and the front edge 72c of the cover body 72 in the inner cover 70 (i.e., the edge portion on the second reflector 40 side) is formed so as to extend in a convex curve along the bottom edge shape of the second reflector 40, so that the following effects can be obtained.

In other words, by configuring the second reflecting mirror 40 as such a concave mirror, it becomes possible to efficiently project the landscape display image PIC onto the display area 102A using the light emitted from the image generating unit 20. On the other hand, the image generating unit 20 and its surrounding structure will end up being projected onto the display area 102A in an enlarged state, so it is particularly effective to adopt the configuration of this embodiment.

In addition, by forming the front edge 72c of the cover body 72 of the inner cover 70 to extend in a convex curve along the shape of the bottom edge of the second reflector 40, the appearance of the structure in the internal space 12 of the housing 50 is not impaired even when it is projected in an enlarged state on the display area 102A.

In the image projection device 10 according to this embodiment, the second reflector 40 is supported so as to be rotatable about an axis Ax that extends in the left-right direction relative to the housing 50, so that the orientation of the second reflector 40 can be adjusted, thereby making it possible to project the display image PIC at the appropriate position in the display area 102A.

To achieve this, in this embodiment, a lever member 46 that extends rearward (i.e., extends in a direction intersecting the axis Ax) is fixed to one of the pair of left and

right shafts

44A, 44B formed on the second reflecting mirror 40, and this lever member 46 is connected to an actuator 48 for rotating the second reflecting mirror 40 about the axis Ax, making it possible to rotate the second reflecting mirror 40 with the minimum number of parts required.

In this embodiment, the base end 46a of the lever member 46 is fixed to the second reflector 40 in a state where it is arranged coaxially with its shaft portion 44B. The housing 50 of this embodiment is configured by assembling a first housing 52 and a second housing 54. The first housing 52 is formed with mounting

portions

52h, 52j for mounting the shaft portion 44A of the second reflector 40 and the base end 46a of the lever member 46. The inner cover 70 is formed with abutment portions 74Ac, 74Bc that abut against the shaft portion 44A of the second reflector 40 and the base end 46a of the lever member 46 mounted on these mounting

portions

52h, 52j. This provides the following advantageous effects.

In other words, it is possible to adjust the orientation of the second reflector 40 without the need to provide a dedicated bracket or the like to rotatably support the second reflector 40. In this case, since the abutment portions 74Ac and 74Bc are formed on the inner cover 70 rather than the second housing 54, the degree of freedom in their shape can be increased, which makes it easy to reliably position the second reflector 40.

Furthermore, in this embodiment, the mounting portion 52j of the first housing 52 and the abutment portion 74Bc of the inner cover 70 are configured as ribs having arc-shaped recesses, and the arm portion 46c of the lever member 46 is formed with an insertion hole 46d for inserting the rear end portion 52j1 of the mounting portion 52j of the first housing 52. Therefore, the second reflector 40 can be positioned in the left-right direction by the engagement between the rear end portion 52j1 of the mounting portion 52j and the inner surface of the insertion hole 46d.

In the above embodiment, the inner cover 70 is attached to the first housing 52 by screwing and lance fixing the pair of left and

right bracket parts

74A, 74B, but it is also possible to position and fix the pair of left and

right bracket parts

74A, 74B by sandwiching them between the first and

second housings

52, 54.

In the above embodiment, the image generating unit 20 is described as being arranged so that its liquid crystal panel 22 faces the internal space 12 of the housing 50, but it is also possible to configure the image generating unit 20 in its entirety to be housed within the internal space 12 of the housing 50.

In the above embodiment, each of the mounting

portions

52h, 52j and each of the contact portions 74Ac, 74Bc has been described as having a semicircular cross-sectional shape, but it is also possible to adopt a trapezoidal cross-sectional shape instead of a semicircular cross-sectional shape.

In the above embodiment, the outer diameter of the base end 46a of the lever member 46 is described as being set to the same value as the tip end of the second shaft portion 44B, but it is also possible to configure them to be set to different values.

In the above embodiment, the

reflective surfaces

30a, 40a of the first and

second reflectors

30, 40 have been described as having a horizontally long rectangular outer shape, but it is also possible to configure them to have an outer shape other than this.

In the above embodiment, the

reflective surfaces

30a, 40a of the first and

second reflectors

30, 40 are described as having a symmetrical shape, but it is also possible to configure them to have an asymmetrical shape.

In the above embodiment, the surface shape of the reflecting surface 30a of the first reflecting mirror 30 is configured as a saddle-shaped curved surface, and the surface shape of the reflecting surface 40a of the second reflecting mirror 40 is configured as a concave curved surface, but it is also possible to configure them with other surface shapes (e.g., flat shapes, etc.).

In the above embodiment, the image generating unit 20 is described as being positioned at the center position in the left-right direction of the reflecting

surfaces

30a, 40a of the first and second reflecting

mirrors

30, 40, but it is also possible to configure the image generating unit 20 to be positioned at a position shifted left-right from the center position.

In the above embodiment, the device is described as having a first and

second reflector

30, 40, but it is also possible to have a configuration with a single reflector (specifically, only the second reflector 40), and even when such a configuration is adopted, it is possible to obtain substantially the same effects as in the above embodiment.

In the above embodiment, the image display unit is described as being configured from the display area 102A of the windshield 102, but it is also possible to configure the image display unit using a translucent plate or the like that is placed on the inside of the windshield 102.

In the above embodiment, the image projection device 10 has been described as an in-vehicle head-up display, but it may also be used for other purposes.

Next, we will explain a variation of the above embodiment.

First, we will explain the first modified example of the above embodiment.

FIG. 9 is a diagram similar to FIG. 7, showing an image projection device 110 according to this modified example.

As shown in FIG. 9, the basic configuration of the image projection device 110 of this modified example is similar to that of the above embodiment, but the configurations of the first housing 152 and the inner cover 170 are different from those of the above embodiment.

In other words, in this modified example, the position where the mounting portion 152j of the first housing 152 is formed and the position where the abutment portion 174Bc of the inner cover 170 is formed are swapped in the left-right direction (i.e., the direction of the axis Ax) from the above embodiment.

In addition, in this modified example, the rear end 174Bc1 of the abutment portion 174Bc of the inner cover 170 is inserted into the insertion hole 46d formed in the arm portion 46c of the lever member 46, and the second reflector 40 is positioned in the left-right direction by the engagement between this rear end 174Bc1 and the inner surface of the insertion hole 46d.

The abutment portion 174Bc is tapered downward, but the rear end 174Bc1 has a constant left-right width and its most distal end is convexly curved. This makes it easy to insert the rear end 174Bc1 into the insertion hole 46d, and even if the arm portion 46c is displaced up or down due to the rotation of the lever member 46, the engagement between the insertion hole 46d of the lever member 46 and the rear end 174Bc1 of the abutment portion 174Bc is maintained with high precision.

Even when the configuration of this modified example is adopted, the same effects as those of the above embodiment can be obtained.

Next, we will explain the second variation of the above embodiment.

FIG. 10 is a diagram similar to FIG. 4, showing an image projection device 210 according to this modified example.

As shown in FIG. 10, the image projection device 210 of this modified example has the same basic configuration as the above embodiment, but differs from the above embodiment in that the second reflector 240 and the lever member 246 are integrally formed (specifically, formed as a single resin molded product).

In other words, in this modified example, the second shaft portion 244B of the second reflector 240 is formed with the same diameter as the base end portion 46a of the lever member 46 in the above embodiment, and the arm portion 246c of the lever member 246 is formed to extend from this second shaft portion 244B. Note that the configuration of the tip end portion 246b of the lever member 246 and the shape of the insertion hole 246d formed in the arm portion 246c are the same as in the above embodiment.

In this modified example, the configuration of the reflecting surface 240a of the second reflecting mirror 240, the pair of left and right vertical flange portions 242, and the first shaft portion 244A are the same as in the above embodiment.

In addition, by adopting the configuration of this modified example, it is possible to reduce the number of parts in the image projection device 210.

Note that the numerical values given as specifications in the above embodiment and its modified examples are merely examples, and it goes without saying that these may be set to different values as appropriate.

Furthermore, the present invention is not limited to the configurations described in the above embodiment and its modified examples, and various other modified configurations can be adopted.

This international application claims priority based on Japanese patent application No. 2022-193458, filed on December 2, 2022, the entire contents of which are incorporated herein by reference.

The above descriptions of specific embodiments of the present invention are presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. It will be apparent to one of ordinary skill in the art that numerous modifications and variations are possible in light of the above description.

2

Driver

10, 110, 210 Image projection device 12 Internal space 20 Image generation unit 22 Liquid crystal panel 30 First reflecting mirror (primary reflecting mirror)
30a, 40a, 240a Reflecting surface 32 Flange portion 32A Side wall portion 32B Stepped

portion

34, 76

Screw

40, 240 Second reflecting mirror (reflecting mirror)
42, 242

Vertical flange portion

44A, 244A

First shaft portion

44B, 244B

Second shaft portion

46, 246 Lever member 46a

Base end portion

46b,

246b Tip portion

46c, 246c

Arm portion

46d, 246d Insertion hole 48 Actuator 48a Output shaft 50

Housing

52, 152 First housing 52a Upper end opening 52b Lower wall portion 52bA, 52bB Boss portion 52c Peripheral wall portion 52d Unit mounting portion 52e Opening 52f Column-shaped protrusion portion 52g Pin 52h, 52j, 152j Mounting portion 52j1, 174Bc1 Rear end portion (tip portion)
52k Lance engagement hole 52m Lance engagement portion 54 Second housing 54a Opening 54b Outer peripheral flange portion 54c Light blocking piece portion 54d Lance 60 Light-transmitting

cover

70, 170 Inner cover 72 Cover main body portion 72a Cylindrical opening 72a1 Lower opening end 72b Rear end edge 72c

Front end edge

74A, 74B Bracket portion 74a Screw insertion hole 74b Lance 74Ac, 74Bc, 174Bc Abutment portion 100 Vehicle 102 Front window 102A Display area (image display portion)
104 Steering wheel Ax Axis PIC Display image R Optical path S Sunlight

Claims

In an image projection device configured to project a display image on an image display unit,
the display device includes an image generating unit that generates an image for display, a reflecting mirror that reflects light emitted from the image generating unit toward the image display unit, and a housing that accommodates the image generating unit and the reflecting mirror,
An image projection device, characterized in that an internal cover that covers the periphery of the image generating unit within the internal space of the housing to the extent that it does not interfere with the incidence of light from the image generating unit to the reflecting mirror.
The image projection device according to claim 1, characterized in that a primary reflector that reflects the light emitted from the image generating unit toward the reflector is disposed in the internal space of the housing.
The reflecting mirror is configured as a concave mirror having a horizontal cross-sectional shape of a concave curve,
3. The image projection device according to claim 1, wherein the inner cover has an edge portion on the side of the reflecting mirror that extends in a convex curve along a lower edge shape of the reflecting mirror.
The reflecting mirror is supported rotatably about an axis extending in the left-right direction relative to the housing,
The housing is configured by assembling a first housing and a second housing,
A shaft portion extending in the axial direction is formed at a side end portion of the reflecting mirror,
The first housing is formed with a mounting portion for mounting the shaft portion,
3. The image projection device according to claim 1 or 2, wherein the inner cover is formed with an abutment portion for abutting against the shaft portion placed on the placement portion to position the reflecting mirror.
A lever member is fixed to the shaft portion and extends in a direction intersecting the axial direction,
the lever member is connected to an actuator for rotating the reflecting mirror about the axis;
the placement portion and/or the contact portion is configured with a rib having an arc-shaped recess,
an insertion hole for inserting a tip end of the placement portion and/or the contact portion through the lever member;
3. The image projection device according to claim 1, wherein the reflector is configured to be positioned in the axial direction by engagement between a tip of the mounting portion and/or the abutment portion and an inner surface of the insertion hole.