Image Projection Device

Abstract

To provide an image projection device capable of effectively suppressing the temperature rise of an image irradiation part due to the external light while maintaining quality of an image to be projected.SOLUTION: An image projection device includes: an image irradiation part (10) for irradiating an image; a reflection transmission part (60) for reflecting the irradiation light from the image irradiation part (10) on the surface and transmitting the light from the rear surface; and an angle-dependent light transmission part (40) in which transmittance of the light in a predetermined polarization plane varies depending on an incident angle. The angle-dependent light transmission part (40) is arranged on an optical path of the irradiation light from the image irradiation part (10) to the reflection transmission part (60).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image projection device, and more particularly to an image projection device that reflects light emitted from an image projection unit to reach a viewpoint. [Background technology]

[0002] Conventionally, dashboards that illuminate icons have been used to display various types of information inside vehicles. 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, because the instrument panel is located below the vehicle's windshield, the driver must undesirably move their eyes downward while driving in order to see the information displayed on the instrument panel. Therefore, image projection devices such as head-up displays (hereinafter referred to as HUDs) have been proposed, which project images onto the windshield so that the driver can read information when looking ahead of the vehicle.

[0004] Fig. 7 is a schematic diagram showing the configuration of a conventional image projection device. As shown in Fig. 7, the conventional image projection device includes an image projection unit 1 and free-form surface mirrors 2 and 3. In such an image projection device, the image projection unit 1 emits illumination light L containing an image, and the illumination light L is reflected by the free-form surface mirrors 2 and 3, and reaches the viewpoint of a driver or the like so that the image is formed in space via the windshield. As a result, the driver or the like can perceive the illumination light L incident on the viewpoint as if an image were being displayed at the imaging position in the depth direction.

[0005] However, in the image projection device shown in Figure 7, when sunlight or other external light Ls enters from the outside, the external light is concentrated on the surface of the image projection unit 1 by the free-form surface mirrors 2 and 3, which can cause the temperature of the image projection unit 1 to rise and deteriorate. Therefore, it has been proposed to form an intermediate image of the projection light L between the multiple free-form surface mirrors 2 and 3, and to place a shielding section or an infrared light cut filter near the intermediate image position to reduce the influence of the external light Ls that reaches the image projection unit from the outside (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2017 / 195740 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the structure using the light-shielding portion described in Patent Document 1, it is unavoidable that external light reaches the image irradiation portion from the space that ensures the optical path of the irradiation light, and there is a limit to how much external light can be restricted from entering.

[0008] Therefore, the present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide an image projection device that can effectively suppress the temperature rise of the image irradiation section due to external light while maintaining the quality of the projected image. [Means for solving the problem]

[0009] In order to solve the above problems, the image projection device of the present invention comprises: An image projection device that projects irradiated light containing an image onto a reflective / transmissive portion, an angle-dependent light-transmitting section in which the transmittance of light in a predetermined polarization plane changes depending on the angle of incidence; and a concave mirror onto which the irradiated light transmitted through the angle-dependent light transmitting portion reaches and which reflects the irradiated light toward the reflection-transmission portion, wherein the angle-dependent light transmitting portion is bent and held in at least one axial direction. It is characterized by the presence of

[0010] In the image projection device of the present invention, the angle-dependent light-transmitting section cuts out external light while allowing light (irradiation light) from the image irradiation section to pass through, thereby providing an image projection device that can effectively suppress temperature increases in the image irradiation section due to external light while maintaining the quality of the projected image.

[0011] In one aspect of the present invention, the angle-dependent light transmitting portion The optical path of the irradiated light An angle changer is provided to change the angle relative to the

[0012] In another aspect of the present invention, The angle-dependent light transmitting portion has a saturation of 20 or less. .

[0013] In one aspect of the present invention, the angle-dependent light transmitting portion has a radius of curvature in the range of 10 mm to 1000 mm.

[0014] In one aspect of the present invention, a polarization selection section is provided that transmits polarized light in a transmission axis direction and blocks polarized light orthogonal to the transmission axis direction, and the polarization selection section is a section extending from the angle-dependent light transmission section to the reflection / transmission section. The optical path of the irradiated light is placed above.

[0015] In one aspect of the present invention, the transmission axis direction of the polarization selection section corresponds to the predetermined polarization plane.

[0016] In one aspect of the present invention, On the optical path of the irradiated light and an intermediate imaging optical unit arranged at the image projection unit and configured to image the light from the image projection unit at an intermediate imaging position.

[0017] In one aspect of the invention, the angle-dependent light-transmitting section is disposed at a position closer to the reflection-transmission section in the optical path of the irradiation light than the intermediate image-forming position. [Effects of the Invention]

[0018] The present invention can provide an image projection device that can effectively suppress a temperature rise in the image irradiation unit due to external light while maintaining the quality of the projected image. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing the configuration of an image projection device 100 according to a first embodiment of the present invention. [Figure 2] 2A and 2B are schematic diagrams showing the positional relationship of optical members in the image projection device 100, with FIG. 2A being a side view and FIG. 2B being a top view. [Figure 3] 3A and 3B are schematic diagrams showing the illumination light L emitted from the image projection unit 10 in the image projection device 100 as a light cone, with FIG. 3A being a top view and FIG. 3B being a side view. [Figure 4] 10 is a graph showing the relationship between the angle of incidence and reflectance of the angle-dependent light transmitting portion 40. [Figure 5] FIG. 10 is a schematic diagram showing the configuration of an image projection device 110 according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram showing the configuration of an image projection device 120 according to a third embodiment of the present invention. [Figure 7] FIG. 1 is a schematic diagram showing the configuration of a conventional image projection device. DETAILED DESCRIPTION OF THE INVENTION

[0020] (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 will be denoted by the same reference numerals, and redundant description will be omitted where appropriate. FIG. 1 is a schematic diagram showing the configuration of an image projection device 100 according to this embodiment. FIG. 2 is a schematic diagram showing the positional relationship of each optical member in the image projection device 100, with FIG. 2(a) being a side view and FIG. 2(b) being a top view. FIG. 3 is a schematic diagram showing the illumination light L irradiated from the image projection unit 10 in the image projection device 100 as a light cone, with FIG. 3(a) being a top view and FIG. 3(b) being a side view.

[0021] 1 to 3, image projection device 100 includes image projection unit 10, free-form surface mirrors 20 and 30, angle-dependent light transmission unit 40, and polarization selection unit 50. In addition, arrows in FIG. 1 indicate typical optical paths of external light Ls, such as sunlight. Furthermore, as shown in FIG. 3, a vehicle windshield 60 is provided outside image projection device 100, and a driver or the like views an image generated by irradiated light L through windshield 60 from a viewpoint.

[0022] The image projection unit 10 is a device that projects light containing image information when a signal containing image information is supplied from an information processing unit (not shown). The light projected from the image projection unit 10 is incident on a free-form surface mirror 20. Examples of the image projection unit 10 include a liquid crystal display device, an organic EL display device, a micro LED display device, a DMD (Digital Micro-mirror Device), and a projector device using a laser light source.

[0023] The free-form surface mirror 20 is a mirror on which illumination light L emitted from the image illumination unit 10 is incident and reflected in the direction of the free-form surface mirror 30 via the angle-dependent light transmitting unit 40. The reflecting surface shape of the free-form surface mirror 20 is formed by a free-form surface whose curvature is not constant but changes two-dimensionally. While FIG. 1 shows a concave mirror as the shape of the free-form surface mirror 20, a convex mirror as shown in FIGS. 2 and 3 or a plane mirror may also be used.

[0024] The free-form surface mirror 30 is a concave mirror onto which the illumination light L reflected by the free-form surface mirror 20 is incident and which reflects the light in the direction of the windshield 60 via the polarization selector 50. The reflecting surface of the free-form surface mirror 30 is configured as a free-form surface whose curvature is not constant but changes two-dimensionally. While FIG. 1 shows the shape of the free-form surface mirror 30 as a concave mirror, a convex mirror or a plane mirror may also be used.

[0025] The angle-dependent light transmitting unit 40 is an optical element having optical properties in which the transmittance of light in a predetermined polarization plane (polarization direction) changes depending on the angle of incidence. The angle-dependent light transmitting unit 40 is disposed between the free-form surface mirror 20 and the free-form surface mirror 30. Although an example in which the angle-dependent light transmitting unit 40 is disposed between the free-form surface mirror 20 and the free-form surface mirror 30 is shown in FIGS. 1 to 3, the position of the angle-dependent light transmitting unit 40 is not limited as long as it is on the optical path from the image projection unit 10 to the windshield (reflection-transmission unit) 60 and the illumination light L emitted from the image projection unit 10 passes through the angle-dependent light transmitting unit 40 and then reaches the windshield 60. The structure and optical properties of the angle-dependent light transmitting unit 40 will be described in detail below using FIG. 4 etc.

[0026] The polarization selection unit 50 is an optical element having the optical property of transmitting light polarized in the transmission axis direction and blocking light polarized orthogonal to the transmission axis direction, and a known polarizing plate or polarizing film can be used. The polarization selection unit 50 is disposed between the free-form surface mirror 30 and the windshield 60. While FIGS. 1 to 3 show an example in which the polarization selection unit 50 is disposed between the free-form surface mirror 30 and the windshield 60, the position of the polarization selection unit 50 is not limited as long as it is located on the optical path of the irradiated light L from the angle-dependent light transmitting unit 40 to the windshield 60. The transmission axis of the polarization selection unit 50 is disposed so as to transmit S-polarized light relative to the windshield 60. The transmission axis direction of the polarization selection unit 50 corresponds to the bending direction of the angle-dependent light transmitting unit 40, and corresponds to S-polarized light relative to the windshield 60. While FIG. 1 shows an example in which the polarization selection unit 50 is provided to transmit only light polarized in the bending direction of the angle-dependent light transmitting unit 40, a configuration without the polarization selection unit 50 is also possible.

[0027] The windshield 60 is provided in front of the driver's seat of the vehicle, and functions as a reflective / transmissive unit on the inside surface of the vehicle, reflecting the incident light L from the free-form surface mirror 30 toward the viewpoint and transmitting light from outside the vehicle toward the viewpoint. While an example is shown in which the windshield 60 is used as the reflective / transmissive unit, a combiner may be provided as a reflective / transmissive unit separate from the windshield 60 to reflect the light from the free-form surface mirror 30 toward the viewpoint. Furthermore, the windshield 60 is not limited to being located at the front of the vehicle, and may be located to the side or rear of the vehicle as long as it projects an image toward the viewpoint of the passenger. The viewpoint is the eye (eyebox) of the driver or passenger of the vehicle, and the driver or passenger views the formed virtual image when the incident light enters the eyebox and reaches the retina.

[0028] The virtual image appears as if it were formed in space when the irradiated light reflected by the windshield 60 reaches the viewpoint (eyebox) of the driver or other person. The position at which the virtual image is formed is determined by the angle at which the light irradiated from the image projection unit 10 spreads as it travels toward the viewpoint after being reflected by the free-form surface mirrors 20, 30 and the windshield 60. At this time, the driver or passenger perceives the virtual image as being located at an imaging position farther away than the windshield 60. Here, the imaging position of the virtual image depends primarily on the combined focal length of the free-form surface mirrors 20 and 30. Even if the windshield 60 is curved rather than flat, the radius of curvature is larger than that of the free-form surface mirrors 20 and 30, so the effect of the optical power of the windshield 60 is negligible.

[0029] 4 is a graph showing the relationship between the angle of incidence and reflectance of the angle-dependent light transmitting unit 40. The horizontal axis of the graph represents the direction perpendicular to the surface of the angle-dependent light transmitting unit 40 as 0 degrees, and the angle tilted from 0 degrees as the angle of incidence. The vertical axis of the graph represents the reflectance of polarized light (P-polarized light) in an in-plane direction including the 0-degree direction of the angle-dependent light transmitting unit 40 and the direction of incidence of the light. As shown in FIG. 4, the angle-dependent light transmitting unit 40 has optical properties in which the reflectance is low (transmittance is high) for light incident at a small angle of incidence close to the perpendicular direction, the reflectance increases (transmittance decreases) as the angle of incidence increases, and the reflectance approaches 100% at angles of incidence greater than a certain angle.

[0030] As the angle-dependent light-transmitting portion 40 having the optical properties shown in Fig. 4, a laminated film manufactured by Toray Industries, Inc. (product name "PICASUS (registered trademark) VT") or a laminated film described in JP 2021-54061 A or the like can be used. In the example shown in Fig. 4, the reflectance reaches a maximum value of 100% when the incident angle is around 40 degrees, but the maximum reflectance and the incident angle at which the maximum value is reached are not limited to this.

[0031] 1 to 3, the angle-dependent light transmitting portion 40 is configured as a substantially flat film shape, and is bent and held in at least one axial direction. Here, the bending direction of the angle-dependent light transmitting portion 40 corresponds to P-polarized light with respect to the windshield 60. Furthermore, the optical characteristics of the angle-dependent light transmitting portion 40 shown in FIG. 4 are for polarized light (P-polarized light) in the bending direction of the angle-dependent light transmitting portion 40.

[0032] As shown in FIG. 1, external light Ls, such as sunlight, enters the windshield 60 from above. Therefore, even within the light cone formed by the irradiated light L, it travels in the opposite direction toward the image projection unit 10 at a different angle from the optical path of the irradiated light L. Furthermore, the transmission axis direction of the polarization selection unit 50 corresponds to the bending direction of the angle-dependent light transmitting unit 40. Therefore, the external light Ls transmitted through the polarization selection unit 50 becomes only P-polarized light and is affected by the optical characteristics of the angle-dependent light transmitting unit 40. In this case, bending the angle-dependent light transmitting unit 40 can increase the angle of incidence of the external light Ls with respect to the angle-dependent light transmitting unit 40. Therefore, the angle of incidence of the irradiated light L with respect to the angle-dependent light transmitting unit 40 is smaller than the angle of incidence of the external light Ls, and because the irradiated light L is bent in the direction of P-polarized light with respect to the windshield 60, the irradiated light L and the external light Ls are reflected (transmitted) with reflectances according to the reflectance characteristics shown in FIG. 4.

[0033] Therefore, by appropriately setting the radius of curvature r of the angle-dependent light transmitting unit 40 and the inclination angle with respect to the optical path of the irradiation light L, it is possible to reduce the reflectance for the irradiation light L and increase the reflectance for the external light Ls. In other words, the irradiation light L irradiated from the image irradiation unit 10 is effectively transmitted through the angle-dependent light transmitting unit 40 and used to project a virtual image, while the external light Ls is reflected by the angle-dependent light transmitting unit 40 and the amount of light that reaches the image irradiation unit 10 can be reduced. This makes it possible to suppress a temperature rise caused by the external light Ls reaching the image irradiation unit 10 and prevent deterioration.

[0034] FIG. 4 shows an example in which the irradiated light L is incident at an incident angle of approximately 15 degrees, as indicated by the solid black bars, and the external light Ls is incident at an incident angle of approximately 35 degrees, as indicated by the open white bars. In this example, the reflectance of the irradiated light L is approximately 20%, and approximately 80% is transmitted. The reflectance of the external light Ls is approximately 80%, and only approximately 20% is transmitted. The incident angles shown in FIG. 4 are just an example, and it is preferable to set the reflectance of the irradiated light L to 30% or less and the reflectance of the external light Ls to 70% or more. Therefore, it is preferable to set the radius of curvature of the angle-dependent light transmitting portion 40 to a range of 10 mm to 1000 mm.

[0035] If the radius of curvature r of the angle-dependent light transmission portion 40 is less than 10 mm, due to the refractive index difference between the angle-dependent light transmission portion 40 and air, the aberration generated in the transmitted irradiation light L increases, and the quality of the projected image may deteriorate, which is not preferable. Also, if the radius of curvature r is too small, the image size that can be projected by the image projection apparatus 100 becomes small, and it is necessary to increase the size of the housing to increase the image size, which is not preferable. Further, if the radius of curvature of the angle-dependent light transmission portion 40 is greater than 1000 mm, it becomes difficult to create a difference in the incident angles of the irradiation light L and the external light Ls, and it also becomes difficult to miniaturize the apparatus. Therefore, by setting the radius of curvature r in the range of 10 mm to 1000 mm, a difference of about 20 to 30 degrees can be provided in the incident angles of the irradiation light L and the external light Ls with respect to the angle-dependent light transmission portion 40, and a difference in reflectance can be ensured.

[0036] Since the irradiation light L reflected by the free-form surface mirror 30 and directed toward the windshield 60 becomes nearly parallel light, the free-form surface mirror 30 is approximated as an elliptical shape for consideration. As shown in FIG. 1, the external light Ls enters the end region of the free-form surface mirror 30, and there is a difference of several degrees (for example, 2.5 degrees) from the optical path of the irradiation light L reflected in the central region. In order to expand such a difference in optical path of several degrees to a difference in incident angle of about 20 to 30 degrees as described above, if the value of the maximum radius of curvature among the curved surfaces constituting the free-form surface mirror 30 is R, it is preferable that R≧r.

[0037] Also, as preferable optical characteristics of the angle-dependent light transmission portion 40, when the reflectances at incident angles of 20 degrees, 40 degrees, and 70 degrees of P-wave or S-wave are R20, R40, and R70 respectively, R20 < R40 < R70 and R70 is 30% or more. By satisfying these conditions for the relationship between the incident angle and the reflectance, the irradiation light L can be transmitted well and the external light Ls can be reflected.

[0038] Also, the chroma of the angle-dependent light transmission portion 40 is preferably 20 or less. By satisfying this condition for the chroma, the color of the irradiation light L is not deteriorated, and deterioration in the quality of the projected virtual image can be suppressed.

[0039] Furthermore, it is preferable that the difference between the maximum and minimum values ​​of reflectance in the visible light range (450 to 650 nm) when light is incident at an incident angle of 70 degrees is less than 40%. When the reflectance difference in the visible light range satisfies these conditions, the reflectance for a wide range of wavelengths included in external light Ls such as sunlight is increased, the amount of external light Ls that reaches the image irradiation unit 10 is reduced, and temperature rise can be suppressed.

[0040] In the image projection device 100 of this embodiment, the illumination light L emitted from the image projection unit 10 passes through the free-form surface mirror 20, the angle-dependent light transmitting unit 40, the free-form surface mirror 30, the polarization selection unit 50, and the windshield 60 to reach the viewpoint. This allows the driver or passenger to view the background through the windshield 60 and a virtual image of the image projected from the image projection device 100 superimposed on top of each other. Furthermore, only P-polarized light of the external light Ls is transmitted by the polarization selection unit 50, and is reflected by the free-form surface mirror 30 to reach the angle-dependent light transmitting unit 40. As described above, the angle-dependent light transmitting unit 40 has a high reflectivity at the incident angle of the external light Ls, so the intensity of the external light Ls that passes through the angle-dependent light transmitting unit 40 and reaches the image projection unit 10 is reduced. This makes it possible to suppress deterioration of the image projection unit 10 due to temperature rise.

[0041] As described above, in the image projection device 100 of this embodiment, the angle-dependent light transmitting section 40 cuts out external light Ls while allowing the irradiated light L from the image irradiating section 10 to pass through, so that the temperature rise of the image irradiating section 10 due to external light Ls can be effectively suppressed while maintaining the quality of the projected image.

[0042] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. 5. Description of content that overlaps with the first embodiment will be omitted. FIG. 5 is a schematic diagram showing the configuration of an image projection device 110 according to this embodiment. As shown in FIG. 5, the image projection device 110 includes an image projection unit 10, free-form surface mirrors 20 and 30, an angle-dependent light transmission unit 40, and a polarization selection unit 50.

[0043] Unlike the first embodiment, the illumination light L reflected by the free-form surface mirror 20 is focused at a predetermined intermediate imaging position 41 between the free-form surface mirror 20 and the free-form surface mirror 30, and reaches the free-form surface mirror 30 after being imaged at the intermediate imaging position 41. Therefore, the free-form surface mirror 20 in this embodiment corresponds to the intermediate imaging optical unit of the present invention. Furthermore, the angle-dependent light transmitting unit 40 is disposed between the free-form surface mirror 20 and the free-form surface mirror 30 at a position closer to the windshield 60 on the optical path of the illumination light L than the intermediate imaging position 41. Therefore, after being focused at the intermediate imaging position 41, the illumination light L passes through the angle-dependent light transmitting unit 40 while expanding its light diameter.

[0044] In the image projection device 110 of this embodiment, the angle-dependent light transmitting unit 40 can also cut external light Ls while allowing the irradiation light L from the image irradiation unit 10 to pass through, so that it is possible to effectively suppress a temperature rise in the image irradiation unit 10 due to external light Ls while maintaining the quality of the projected image. Furthermore, because the irradiation light L is condensed at the intermediate imaging position 41 and the angle-dependent light transmitting unit 40 is disposed at the intermediate imaging position 41, the area of ​​the angle-dependent light transmitting unit 40 can be reduced, thereby making the device more compact and lightweight.

[0045] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. 6. Description of content that overlaps with the first embodiment will be omitted. FIG. 6 is a schematic diagram showing the configuration of an image projection device 120 according to this embodiment. As shown in FIG. 6, the image projection device 120 includes an image projection unit 10, free-form surface mirrors 20 and 30, an angle-dependent light transmission unit 40, and a polarization selection unit 50. Unlike the first embodiment, the angle-dependent light transmission unit 40 is disposed between the image projection unit 10 and the free-form surface mirror 20.

[0046] In the image projection device 120 of this embodiment, the angle-dependent light transmitting section 40 is also disposed, so that the irradiated light L is transmitted well to project an image, while external light Ls is cut off to suppress a temperature rise in the image irradiating section 10. Furthermore, by providing the angle-dependent light transmitting section 40 in a position close to the image irradiating section 10, the area of ​​the angle-dependent light transmitting section 40 can be reduced to the minimum necessary, thereby saving space. Furthermore, a sufficient optical path for the irradiated light L can be secured between the free-form surface mirror 20 and the free-form surface mirror 30, improving the degree of freedom in design.

[0047] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described. In the first to third embodiments, an example is shown in which the angle of the angle-dependent light transmitting unit 40 relative to the optical path of the irradiation light L is fixed, but an angle changing unit that mechanically changes the angle of the angle-dependent light transmitting unit 40 may be provided. The specific configuration of the angle changing unit is not limited, but an example is a configuration in which the outer periphery of the angle-dependent light transmitting unit 40 is held by a holder and the position of the holder is changed using a separately provided power source.

[0048] Furthermore, in the first to third embodiments, an example has been shown in which the projection optical system made up of the free-form surface mirrors 20, 30 focuses the illumination light L on the image projection unit 10 side of the windshield 60, thereby projecting a virtual image farther away than the windshield 60. However, the position at which the projected image is focused is not limited, and the projection optical system made up of the free-form surface mirrors 20, 30 may focus the illumination light L between the windshield 60 and the viewpoint, thereby projecting a real image closer to the viewpoint than the windshield 60.

[0049] 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]

[0050] 100, 110, 120...Image projection device 10...Image irradiation unit 20,30...Freeform mirror 40...Angle-dependent light transmission part 41...Intermediate imaging position 50...Polarization selection section 60...Windshield

Claims

1. An image projection device that projects irradiation light containing an image onto a reflective / transmissive section, an image irradiation unit that irradiates the irradiation light; an angle-dependent light-transmitting portion in which the transmittance of light in a predetermined polarization plane changes depending on the angle of incidence; a concave mirror that receives the illumination light that has passed through the angle-dependent light-transmitting unit and reflects the illumination light toward the reflection-transmission unit, The image projection device, wherein the angle-dependent light-transmitting portion is bent and held in at least one axial direction.

2. 2. The image projection device according to claim 1, an angle changing unit that changes the angle of the angle-dependent light transmitting unit with respect to the optical path of the irradiated light;

3. 3. The image projection device according to claim 1, The image projection device, wherein the angle-dependent light transmitting portion has a saturation of 20 or less.

4. 4. The image projection device according to claim 1, The image projection device is characterized in that the angle-dependent light transmitting portion has a radius of curvature in the range of 10 mm to 1000 mm.

5. 5. The image projection device according to claim 1, a polarization selection unit that transmits polarized light in a transmission axis direction and blocks polarized light orthogonal to the transmission axis direction, The image projection device is characterized in that the polarization selection unit is disposed on an optical path of the irradiated light from the angle-dependent light transmission unit to the reflection / transmission unit.

6. 6. The image projection device according to claim 5, 10. An image projection device, comprising: a polarization selecting section having a transmission axis direction corresponding to the predetermined polarization plane;

7. 7. The image projection device according to claim 1, an intermediate imaging optical unit that is arranged on an optical path of the irradiation light from the image irradiation unit to the reflection / transmission unit and that images the light from the image irradiation unit at an intermediate imaging position.

8. 8. The image projection device according to claim 7, The image projection device, wherein the angle-dependent light-transmitting section is disposed at a position closer to the reflection-transmission section in the optical path of the irradiation light than the intermediate image-forming position.

Images