Image projection device

Abstract

To provide an image projection device capable of ensuring visibility even when polarized sunglasses are used.SOLUTION: An image projection device (100) which projects a projection image on a display part (WS) for displaying a virtual image includes: an image irradiation part (10) for emitting image light (L1); a projection optical part (20) for projecting the image light (L1) as the projection image on the display part (WS); and a polarization adjustment part (30) for adjusting a polarization direction of the image light (L1). The image light (L1) emitted from the projection optical part (20) contains P-polarized light relative to the display part (WS).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image projection device, and particularly to an image projection device that reflects irradiation light from an image irradiation unit to make the light reach a viewpoint.

Background Art

[0002] Conventionally, as a device for displaying various types of information in a vehicle, an instrument panel that lights and displays icons has been used. Along with the increase in the amount of information to be displayed, it has also been proposed to embed an image display device in the instrument panel, or to configure the entire instrument panel with an image display device.

[0003] However, since the instrument panel is located below the windshield of the vehicle, it is not preferable for the driver to visually recognize the information displayed on the instrument panel, as the driver needs to move the line of sight downward during driving. Accordingly, a head-up display (hereinafter referred to as HUD: Head Up Display) that projects an image onto the windshield so that the driver can read the information when visually recognizing the front of the vehicle has also been proposed (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in conventional image projection devices, the reflection of light from the windshield tends to have a low reflectivity for the P-polarized component and a high reflectivity for the S-polarized component. Therefore, the polarization direction of the light emitted from the image projection unit is set to be S-polarized relative to the windshield. As a result, the light that reaches the viewpoint is S-polarized light only, without any P-polarization.

[0006] However, in environments with strong sunlight or when driving on snowy roads, passengers may wear polarized sunglasses to see outside through the windshield. In this case, the light reflected by objects outside the vehicle is also S-polarized, and polarized sunglasses are designed to cut S-polarized light and transmit P-polarized light. Therefore, for passengers wearing polarized sunglasses, the S-polarized light reflected by the windshield is cut off by the sunglasses, making it difficult to see the image formed by the illuminated light.

[0007] Therefore, the present invention has been made in view of the above-mentioned conventional problems, and aims to provide an image projection device that can ensure visibility even when using polarized sunglasses or the like. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides an image projection apparatus for projecting a projection image onto a display unit for displaying a virtual image, comprising: an image illumination unit for irradiating image light; and a projection optical unit for projecting the image light onto the display unit as the projection image, wherein the image light irradiated from the projection optical unit includes P-polarized light for the display unit. Irradiated from the aforementioned projection optical unit The system includes a polarization adjustment unit that adjusts the polarization direction of the image light. The polarization adjustment unit is a polarization compensation plate that changes a portion of the P-polarized light to S-polarized light according to the angle of incidence of the image light. It is characterized by the following:

[0009] In the image projection device of the present invention, the polarization direction of the image light is adjusted in the polarization adjustment unit, so that the distribution of the polarization direction of the image light can be set to an appropriate value according to the curved shape of the display unit, and visibility can be ensured even when using polarized sunglasses or the like.

[0012] Furthermore, in one aspect of the present invention, the polarization compensation plate is arranged in a curved manner.

[0013] In one aspect of the present invention, the polarization adjustment unit is provided between the projection optical unit and the display unit.

[0014] Furthermore, in one aspect of the present invention, the polarization adjustment unit adjusts the polarization direction of at least a portion of the image light irradiated from the projection optical unit within a range of 30 degrees or less. [Effects of the Invention]

[0015] The present invention provides an image projection device that can ensure visibility even when using polarized sunglasses or the like. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing the configuration of the image projection device 100 according to the first embodiment. [Figure 2] This graph schematically shows an example of the reflection characteristics of P-polarized and S-polarized light at the polarized reflection section 40. [Figure 3] This is a schematic diagram showing the change in the incident angle and polarization direction of the image light L1 in the polarization adjustment unit 30. [Figure 4] This is a schematic diagram showing the configuration of the image projection device 110 according to the second embodiment. [Figure 5] This is a schematic diagram showing the configuration of the image projection device 120 according to the third embodiment. [Modes for carrying out the invention]

[0017] (First Embodiment) Embodiments of the present invention will be described in detail below 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 explanations will be omitted as appropriate. Figure 1 is a schematic diagram showing the configuration of the image projection device 100 according to this embodiment.

[0018] As shown in Figure 1, the image projection device 100 includes an image irradiation unit 10, a free-form surface mirror 20, and a polarization adjustment unit 30. The free-form surface mirror 20 constitutes the projection optical unit in the present invention. In Figure 1, representative optical paths of the image light L1 emitted from the image irradiation unit 10 and external light L0 such as sunlight are schematically indicated by solid line arrows. Further, a vehicle windshield WS and a polarization reflection unit 40 are provided outside the image projection device 100, and a driver or the like visually recognizes an image formed by the image light L1 via the polarization reflection unit 40 from the position of the viewpoint e.

[0019] The image irradiation unit 10 is a device that emits irradiation light (image light) L1 containing image information when a signal including the image information is supplied from an information processing unit (not shown). The image light L1 emitted from the image irradiation unit 10 enters the free-form surface mirror 20. Examples of the image irradiation 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. The image light L1 emitted from the image irradiation unit 10 is configured to include light that becomes P-polarized light with respect to the windshield WS, as indicated by the double-headed arrow in the figure. When the image light L1 from the image irradiation unit 10 is polarized in a specific direction, the orientation of the display surface of the image irradiation unit 10 is set so that its polarization plane becomes P-polarized light with respect to the windshield WS. Examples of the image irradiation unit 10 that emits the image light L1 of specific polarized light include a liquid crystal display device, a projector device using a laser light source, and a reflective liquid crystal projector device.

[0020] The free-form surface mirror 20 is a mirror onto which the image light L1 emitted from the image irradiation unit 10 is incident, and which reflects the image light L1 toward the windshield WS. The reflective surface shape of the free-form surface mirror 20 is configured as a free-form surface whose curvature is not constant but changes two-dimensionally. Although a concave mirror is shown as the shape of the free-form surface mirror 20 in FIG. 1, a convex mirror may be used, or a plane mirror may be used. Further, although FIG. 1 shows an example in which the free-form surface mirror 20 constitutes the projection optical unit, a plurality of reflecting mirrors may be used to repeatedly reflect the image light L1 to irradiate the windshield WS.

[0021] The polarization adjustment unit 30 is an optical member that adjusts the polarization direction of the image light L1. The specific configuration of the polarization adjustment unit 30 is not limited, but a polarization compensator whose polarization direction is changed according to the incident angle of light can be used. The configuration of the polarization compensator is not limited, and those of known materials and structures can be used, and as an example, a WV film manufactured by Fujifilm Corporation, a Holographic Optical Element (HOE), or the like can be used.

[0022] In the example shown in FIG. 1, a polarization compensator is used as the polarization adjustment unit 30, and the polarization compensator is arranged in a curved manner. Thereby, the incident angle of the image light L1 to the polarization compensator in the irradiation region has a predetermined distribution, and the polarization direction of the image light L1 also has a predetermined distribution in the irradiation region. Although FIG. 1 shows an example in which the polarization adjustment unit 30 is provided between the free-form surface mirror 20 and the windshield WS, the position where the polarization adjustment unit 30 is provided is not limited, and may be between the free-form surface mirror 20 and the image irradiation unit 10. In order to determine the final distribution of the polarization direction of the image light L1 projected from the image projection device 100, it is preferable to arrange the polarization adjustment unit 30 at the emission position of the image light L1 in the image projection device 100.

[0023] The windshield WS is located in front of the driver's seat of the vehicle and transmits light from outside the vehicle in the direction of viewpoint e. Furthermore, since the windshield WS transmits at least visible light from outside the vehicle, even when external light L0 such as sunlight enters the vehicle from above, a portion of the external light L0 reaches the free-form mirror 20. A polarizing reflector 40 is also provided inside the windshield WS. In Figure 1, for simplicity, the cross-sectional shape of the windshield WS is depicted as a flat plate, but in an actual vehicle, it is composed of a curved surface with curvature in the vertical and horizontal directions. Furthermore, the area of ​​the windshield WS on which the image light L1 is projected is on the driver's seat side and is located off-center from the left-right center of the windshield WS, and is composed of an asymmetrical curved surface.

[0024] The polarizing reflective portion 40 is an optical element provided inside the windshield WS, and has optical properties in which the reflectance of the S-polarized component of incident light is low and the reflectance of the P-polarized component is high. In the example shown in Figure 1, the polarizing reflective portion 40 is configured as a substantially flat film shape and is embedded inside the windshield WS. Although Figure 1 shows an example in which the polarizing reflective portion 40 is provided on a part of the windshield WS, it may also be provided on the entire surface of the windshield WS.

[0025] Figure 2 is a schematic graph showing an example of the reflection characteristics of P-polarized and S-polarized light at the polarizing reflector 40. The horizontal axis of the graph shows the angle of incidence, with the direction perpendicular to the surface of the polarizing reflector 40 being 0 degrees. The vertical axis of the graph shows the reflectance of polarization (P-polarized light) in the in-plane direction including the 0-degree direction and the direction of light incidence as a solid line, and the reflectance of S-polarized light perpendicular to P-polarized light as a dashed line. As shown in Figure 2, the polarizing reflector 40 has optical properties in which it has a high reflectance of P-polarized light and a low reflectance of S-polarized light relative to the windshield WS. Furthermore, the reflectance of P-polarized light is low at small angles of incidence and increases as the angle of incidence increases. Also, as shown in Figure 2, the polarizing reflector 40 has a high reflectance of over 75% for P-polarized light and a low reflectance of about 10% for S-polarized light near the Brewster angle of the windshield WS. As the polarizing reflective portion 40 having the optical properties shown in Figure 2, a polarizing reflective film (WCF-PVB) manufactured by 3M Corporation or one described in Japanese Patent Publication No. 2006-512622 can be used.

[0026] Furthermore, although Figure 1 shows an example in which a polarizing reflector 40 is provided inside the windshield WS as the display unit, a combiner may be prepared separately as the display unit, and the polarizing reflector 40 may be provided inside the combiner to reflect light from the free-form mirror 20 in the direction of the viewpoint. Also, the display unit is not limited to being located in front of the vehicle, but may be placed to the side or rear as long as it projects an image to the viewpoint e of the occupant. The viewpoint e is the eye (eyebox) of the vehicle driver or occupant, and when the image light L1 enters the eyebox and the light reaches the retina, the driver or occupant sees the formed virtual image.

[0027] The virtual image is displayed as if it were formed in space when the image light L1 reflected by the polarizing reflector 40 reaches the viewpoint (eyebox) e of the driver or other passenger. The position where the virtual image is formed is determined by the angle of spread of the light emitted from the image projection unit 10 as it travels in the direction of the viewpoint after being reflected by the free-form mirror 20 and the polarizing reflector 40. At this time, the driver or passenger perceives the virtual image as being located at a position farther away from the windshield WS. Here, the position where the virtual image is formed mainly depends on the combined focal length of the projection optics unit. Even if the windshield WS is a curved surface rather than a flat surface, the effect of the optical power from the windshield WS is negligible because its radius of curvature is larger than that of the free-form mirror 20.

[0028] As shown in Figure 1, the image light L1 from the image illumination unit 10 contains P-polarization for the windshield WS, and the image light L1 reflected by the free-form mirror 20 also contains P-polarization. In addition, although the polarization direction of a portion of the image light L1 is changed in the polarization adjustment unit 30, it mainly contains P-polarization. Therefore, the image light L1 containing P-polarization passes through the polarization adjustment unit 30 and reaches the polarization reflection unit 40. As shown in Figure 2, the polarization reflection unit 40 has a high reflectivity for P-polarization, so the P-polarization component of the image light L1 is also well reflected and reaches the viewpoint e. Therefore, the virtual image is projected by P-polarization, making it easily visible even when the occupant is wearing polarized sunglasses.

[0029] Furthermore, it is preferable that the incident angle of the image light L1 on the windshield WS be set to the Brewster angle. At the Brewster angle, the P-polarized light of the image light L1 is hardly reflected by the surface of the windshield WS and can be incorporated into the glass that makes up the windshield WS. As shown in Figure 2, the polarization reflector 40 has a high reflectivity even at the Brewster angle, which is close to an incident angle of 50 degrees, and the brightness of the image light L1 reflected by the polarization reflector 40 is greater than the brightness of the image light L1 that is slightly reflected by the surface of the windshield WS. As a result, the P-polarized light of the image light L1 is reflected by both the surface of the windshield WS and the polarization reflector 40, which suppresses the perception of a double virtual image.

[0030] As shown in Figure 1, ambient light L0, such as sunlight, is incident from above the windshield WS. Here, ambient light L0 incident from outside the vehicle is unpolarized, containing components of all polarization directions. However, the P-polarized component is reflected outwards by the polarization reflector 40, and only the S-polarized component passes through the windshield WS and reaches the free-form mirror 20. Therefore, the P-polarized component of the ambient light L0 is cut off by the polarization reflector 40, and the amount of light reaching the image illumination unit 10 can be suppressed. This suppresses the temperature rise caused by ambient light L0 reaching the image illumination unit 10, and prevents deterioration of the image illumination unit 10.

[0031] As described above, the windshield WS has curvature in the vertical and horizontal directions, and the area onto which the image light L1 is projected is off-center from the center of the windshield WS. In other words, within the area onto which the image light L1 is projected onto the surface of the windshield WS and the polarization reflecting part 40, the inclination direction differs slightly within the plane. When image light L1, which has the same polarization direction throughout, is projected onto such a surface with different inclination directions, the polarization components are separated according to the inclination direction of the incident position, resulting in the generation of P-polarized and S-polarized components. When the polarization components of the image light L1 are separated according to the incident position in this way, the S-polarized component is reflected by the surface of the windshield WS, and the P-polarized component reflected by the polarization reflecting part 40 decreases, forming a double virtual image and degrading visibility.

[0032] Therefore, in this embodiment, the polarization adjustment unit 30 is arranged in a curved shape to change the polarization direction distribution of the image light L1 transmitted through the polarization adjustment unit 30 so that the polarization direction is suitable for the tilt angle of the windshield WS and the polarization reflection unit 40. Here, changing the polarization direction distribution of the image light L1 means adjusting the polarization direction within a range of 30 degrees for at least a portion of the image light L1 irradiated from the free-form mirror 20. Since the shape of the windshield WS differs depending on the vehicle model and individual differences, by adjusting the polarization direction with the polarization adjustment unit 30, it is possible to project image light L1 with an appropriate polarization distribution according to the vehicle model and individual differences onto the windshield WS. Furthermore, by providing the polarization adjustment unit 30 at the emission position of the image light L1 in the image projection device 100, the image projection device 100 can be aligned with respect to the tilt direction of the windshield WS at the end of the assembly process when mounting it on the vehicle.

[0033] Figure 3 is a schematic diagram showing the change in the incident angle and polarization direction of the image light L1 in the polarization adjustment unit 30. In this embodiment, as shown in Figure 3, a curved polarization compensation plate is used as the polarization adjustment unit 30. The arrows in the figure indicate the direction of propagation of the image light L1, and the double arrows in the figure schematically indicate the polarization direction of the image light L1.

[0034] As shown in Figure 3, the polarization adjustment unit 30 has a curved polarization compensator plate, so the incident angle differs depending on the position of the image light L1. In the region of the image light L1 that is incident perpendicular to the polarization compensator plate, the P polarization is maintained even after passing through the polarizing compensator plate. Using this P polarization as a reference, the conversion of the polarization direction at other positions will be explained. In the region that is incident with an inclination angle to the normal direction of the polarization compensator plate, a portion of the P polarization component is converted to an S polarization component according to the inclination angle, resulting in a polarization direction that includes both P and S polarization components, different from the reference P polarization direction. In Figure 3, at the position shown on the left, the P polarization becomes P1+S1 after passing through the polarizing compensator plate, and at the position shown on the right, the polarization becomes P2+S2.

[0035] Therefore, the image light L1 transmitted through the polarization adjustment unit 30 has a distribution of polarization directions that differ depending on its position within the plane of the irradiated area. This distribution of polarization directions is determined by the optical properties and curvature of the polarization compensation plate, which is the polarization adjustment unit 30. Therefore, by matching the curvature of the polarization compensation plate to the tilt direction of the windshield WS in the irradiated area of ​​the image light L1, the tilt direction of the windshield WS and the polarization direction of the image light L1 can be appropriately set at each position.

[0036] In the example shown in Figure 3, the image light L1, which is incident perpendicularly to the polarization compensation plate and transmitted through it, reaches the windshield WS with only the reference P polarization component remaining, and thus only the P polarization component remains with respect to the tilt direction of the windshield WS. At this position, the direction of the reference P polarization is the in-plane polarization that includes the incident direction of the image light L1 and the normal direction of the windshield WS.

[0037] Image light L1, incident on the polarization compensation plate at a predetermined inclination angle, reaches the windshield WS with a polarization direction of P1+S1 or P2+S2, which is different from the reference P-polarization. At this position, the normal direction of the windshield WS has a horizontal inclination component compared to the position where the reference P-polarization was incident, and cancels out the S1 and S2 components of the P1+S1 or P2+S2 polarization direction. Therefore, at this position, the relationship between the normal direction of the windshield WS and the polarization direction of the image light L1 is only that of the P-polarization component, P1 or P2. As a result, the reflection of the S-polarization component at the surface of the windshield WS is suppressed, and the P-polarization component is taken into the windshield WS at the Brewster angle and reflected well by the polarization reflector 40.

[0038] As described above, in the image projection device 100 of this embodiment, the polarization direction of the image light L1 is adjusted by the polarization adjustment unit 30, so that the distribution of the polarization direction of the image light L1 can be set to an appropriate one according to the curved shape of the windshield WS, and visibility can be ensured even when using polarized sunglasses or the like.

[0039] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figure 4. Content that overlaps with the first embodiment will be omitted from the explanation. Figure 4 is a schematic diagram showing the configuration of the image projection device 110 according to this embodiment. As shown in Figure 4, the image projection device 110 includes an image irradiation unit 10, a free-form surface mirror 20, a polarization adjustment unit 30, and a half-wave plate 50. In this embodiment, the half-wave plate 50 is positioned between the image irradiation unit 10 and the free-form surface mirror 20.

[0040] The half-wave plate 50 is an optical element positioned on the optical path of the illumination light (image light) L1, and generates a phase difference of half a wavelength between the mutually orthogonal fast axis and slow axis. Furthermore, the fast axis of the half-wave plate 50 is positioned so as to be 45 degrees different from the S-polarization component and P-polarization component of the image light L1, respectively.

[0041] As shown in Figure 4, in the image projection device 110 of this embodiment, the image light L1 from the image irradiation unit 10 is S-polarized with respect to the windshield WS. In the half-wave plate 50, the polarization direction of the S-polarized light and the fast axis are 45 degrees apart, so the image light L1 transmitted through the half-wave plate 50 becomes P-polarized.

[0042] The image light L1, converted to P-polarization by the half-wave plate 50, is reflected by the free-form mirror 20, passes through the polarization adjustment unit 30, and is projected onto the windshield WS. As described above, the image light L1 that has passed through the polarization adjustment unit 30 is converted to have a polarization direction distribution within the illumination area, as shown in Figure 4, and reaches the windshield WS. Therefore, the S-polarization component contained in the image light L1 is canceled out by the horizontal tilt angle at each position of the windshield WS.

[0043] In the image projection device 110 of this embodiment, the polarization direction of the image light L1 is adjusted by the polarization adjustment unit 30, so that the distribution of the polarization direction of the image light L1 can be set to an appropriate one according to the curved shape of the windshield WS, and visibility can be ensured even when using polarized sunglasses or the like.

[0044] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Figure 5. Content that overlaps with the first embodiment will be omitted from the explanation. Figure 5 is a schematic diagram showing the configuration of the image projection device 120 according to this embodiment. As shown in Figure 5, the image projection device 120 includes an image irradiation unit 10, a free-form surface mirror 20, a polarization adjustment unit 30, and a half-wave plate 50. In this embodiment, the half-wave plate 50 is positioned between the free-form surface mirror 20 and the polarization adjustment unit 30.

[0045] As shown in Figure 5, in the image projection device 120 of this embodiment, the image light L1 from the image irradiation unit 10 is S-polarized with respect to the windshield WS. The S-polarized image light L1 is reflected by the free-form mirror 20 and reaches the half-wave plate 50. At the half-wave plate 50, the polarization direction of the S-polarized light and the fast axis are 45 degrees apart, so the image light L1 transmitted through the half-wave plate 50 becomes P-polarized.

[0046] The image light L1, converted to P-polarization by the half-wave plate 50, passes through the polarization adjustment unit 30 and is projected onto the windshield WS. As described above, the image light L1 that has passed through the polarization adjustment unit 30 is converted to have a polarization direction distribution within the illumination area, as shown in Figure 5, and reaches the windshield WS. Therefore, the S-polarization component contained in the image light L1 is canceled out by the horizontal tilt angle at each position of the windshield WS.

[0047] In the image projection device 120 of this embodiment, the polarization direction of the image light L1 is adjusted by the polarization adjustment unit 30, so that the distribution of the polarization direction of the image light L1 can be set to an appropriate one according to the curved shape of the windshield WS, and visibility can be ensured even when using polarized sunglasses or the like.

[0048] (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. Details that overlap with the first embodiment will be omitted. In the first to third embodiments, an example was shown in which a polarization compensation plate was used as the polarization adjustment unit 30. However, a polarizing plate that transmits polarization in a predetermined direction may also be used as the polarization adjustment unit 30.

[0049] For example, consider a scenario where image light L1 is emitted from the image illumination unit 10 with polarization in a predetermined direction, but the tilt direction of the windshield WS does not match the polarization direction of the image light L1 due to vehicle type or manufacturing tolerances. In this case, the image light L1 that reaches the windshield WS contains both P-polarization and S-polarization components corresponding to the tilt direction. As a result, a double image of a virtual image is formed by the S-polarization reflected from the surface of the windshield WS and the P-polarization reflected from the polarization reflecting unit 40, reducing visibility.

[0050] Therefore, by arranging the polarization direction through which the polarizing plate, which is the polarization adjustment unit 30, is transmitted, in accordance with the tilt of the windshield WS, the S-polarization component in the tilt direction of the windshield WS is cut. As a result, the image light L1 reaching the windshield WS becomes P-polarized with respect to the tilt direction of the windshield WS, suppressing double imaging of virtual images and improving visibility.

[0051] If the angular difference between the polarization direction of the polarizing plate and the polarization direction of the image light L1 is greater than 30 degrees, the amount of light L1 transmitted through the polarizing plate decreases, and the brightness of the virtual image decreases. Therefore, it is preferable that the angular difference between the polarization direction transmitted by the polarizing plate, which is the polarization adjustment unit 30, and the polarization direction of the image light L1 irradiated by the image irradiation unit 10 is within the range of 30 degrees.

[0052] The present invention is not limited to the embodiments described above, 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]

[0053] 100, 110, 120… Image projection devices 10…Image illumination area 20…Free-form surface mirror (projection optics section) 30…Polarization adjustment section 40... Polarized reflective part 50... Half-wave plate

Claims

1. An image projection device that projects a projected image onto a display unit for displaying a virtual image, An image illumination unit that emits image light, The system includes a projection optical unit that projects the image light onto the display unit as the projected image, The image light emitted from the projection optical unit includes P-polarized light for the display unit. The system includes a polarization adjustment unit that adjusts the polarization direction of the image light emitted from the projection optical unit, The image projection apparatus is characterized in that the polarization adjustment unit is a polarization compensation plate that changes a portion of the P-polarized light to S-polarized light according to the angle of incidence of the image light.

2. An image projection device according to claim 1, The image projection apparatus is characterized in that the polarization compensation plate is arranged in a curved manner.

3. An image projection device according to claim 1, The image projection apparatus is characterized in that the polarization adjustment unit is provided between the projection optical unit and the display unit.

4. An image projection device according to any one of claims 1 to 3, The image projection apparatus is characterized in that the polarization adjustment unit adjusts the polarization direction of at least a portion of the image light irradiated from the projection optical unit within a range of 30 degrees or less.

Images