Image projection device

Abstract

Provided is an image projection device capable of uniformizing the luminance distribution while enhancing the luminance by arranging a plurality of light-emitting elements at high density. The image projection device comprises: an image display unit in which a display region for displaying an image is set in a part of the entire display region; a plurality of light-emitting elements (12) that irradiate the image display unit with backlight; and a plurality of first lenses (13) provided corresponding to the plurality of light-emitting elements (12). The plurality of light-emitting elements (12) are two-dimensionally arranged in an arrangement region partitioned off by a long-side direction (X) and a short-side direction (Y) along a direction (a) along the long-side direction (X) and a direction (b) different from the short-side direction (Y) by a prescribed angle.

Description

Image projection device

[0001] This invention relates to an image projection device.

[0002] Traditionally, instrument panels that display various information within vehicles have been used, typically by illuminating icons. Furthermore, with the increasing amount of information to be displayed, proposals have been made to embed image display devices within the instrument panel, or even to construct the entire instrument panel using image display devices.

[0003] However, since the instrument panel is located below the vehicle's windshield, it is undesirable for the driver or other passengers to shift their gaze downwards while driving in order to view the information displayed on the instrument panel. Therefore, image projection devices such as head-up displays (HUDs) have been proposed that project images onto the windshield so that passengers can read the information when they look ahead at the vehicle. (See, for example, Patent Documents 1 and 2).

[0004] The image projection devices described in Patent Documents 1 and 2 involve an image irradiation unit irradiating image light containing an image, reflecting the image light with a free-form surface mirror or the like, and directing it to the position of the occupant's viewpoint so that an image is formed in space via a display unit such as a windshield. As a result, the occupant can perceive that a virtual image is displayed at the image formation position in the depth direction due to the image light incident on their viewpoint.

[0005] Japanese Patent Publication No. 2019-119248 Japanese Patent Publication No. 2019-119262

[0006] The virtual image projected from an image projection device is required to have increased brightness to improve visibility. However, increasing the density of light-emitting elements to increase brightness leads to uneven brightness distribution within the image display area, resulting in a decrease in image quality.

[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 increase brightness by arranging multiple light-emitting elements at high density while also making the brightness distribution uniform.

[0008] To solve the above problems, the image projection device of the present invention comprises an image display unit in which a display area for displaying an image is set in a part of the entire display area, a plurality of light-emitting elements that irradiate the image display unit with backlight light, and a plurality of first lenses provided corresponding to the plurality of light-emitting elements, wherein the plurality of light-emitting elements are arranged two-dimensionally within an arrangement area divided by the long side direction and the short side direction, along a direction along the long side direction and a direction different by a predetermined angle from the short side direction.

[0009] In the image projection apparatus of the present invention, multiple light-emitting elements are arranged two-dimensionally within an arrangement area divided by the long side and the short side, along a direction parallel to the long side and a direction different by a predetermined angle from the short side. This makes it possible to increase brightness by arranging multiple light-emitting elements at high density while simultaneously achieving a uniform brightness distribution.

[0010] Furthermore, in one embodiment of the present invention, the predetermined angle is in the range of 15 degrees or more and 45 degrees or less.

[0011] Furthermore, in one aspect of the present invention, the plurality of light-emitting elements are arranged to form an isosceles triangle with the longer side as the base and the shorter side as the height, and the predetermined angle is less than 30 degrees.

[0012] Furthermore, in one aspect of the present invention, the first lens has an elliptical surface with the long side direction as the minor axis and the short side direction as the major axis.

[0013] Furthermore, in one aspect of the present invention, the first lens has a large divergence angle of the backlight light at the center in the direction of the long side, and a small divergence angle of the backlight light at the ends.

[0014] Furthermore, in one aspect of the present invention, a second lens is provided for adjusting the light distribution of the backlight light emitted from the first lens, the second lens being provided with a plurality of fine steps, the divergence angle of the backlight light being large at the center in the direction of the long side and small at the ends.

[0015] Furthermore, in order to solve the above problems, the image projection device of the present invention comprises an image display unit in which a display area for displaying an image is set in a part of the entire display area, a plurality of light-emitting elements that irradiate the image display unit with backlight light, and a plurality of first lenses provided corresponding to the plurality of light-emitting elements, wherein the plurality of light-emitting elements are arranged in an arrangement area divided by the long side direction and the short side direction, and the first lenses are characterized in that the divergence angle of the backlight light is large at the center in the long side direction and small at the ends.

[0016] In the image projection apparatus of the present invention, the multiple first lenses have a large divergence angle of backlight light at the center in the direction of the long side and a small divergence angle of backlight light at the ends. This makes it possible to increase brightness by arranging multiple light-emitting elements at high density while making the brightness distribution uniform.

[0017] Furthermore, in order to solve the above problems, the image projection device of the present invention comprises an image display unit in which a display area for displaying an image is set in a part of the entire display area, a plurality of light-emitting elements that irradiate the image display unit with backlight light, a plurality of first lenses provided corresponding to the plurality of light-emitting elements, and a second lens that adjusts the light distribution of the backlight light emitted from the first lens, wherein the plurality of light-emitting elements are arranged in an arrangement area divided by the long side direction and the short side direction, and the second lens is provided with a plurality of fine steps, characterized in that the divergence angle of the backlight light is large at the center in the long side direction and small at the ends.

[0018] In the image projection apparatus of the present invention, the second lens is provided with multiple fine steps, and the divergence angle of the backlight light is large in the center in the direction of the long side, and small at the edges. This makes it possible to increase the brightness by arranging multiple light-emitting elements at high density while making the brightness distribution uniform.

[0019] Furthermore, in one aspect of the present invention, the area of ​​the arrangement area is smaller than the entire display area, and the backlight is irradiated onto the display area.

[0020] The present invention provides an image projection device that can increase brightness by arranging multiple light-emitting elements at high density while simultaneously achieving a uniform brightness distribution.

[0021] This is a schematic diagram illustrating the projection of a virtual image using the image projection device 100 according to the first embodiment. This is a schematic cross-sectional view illustrating the outline of the image illumination unit 10 according to the first embodiment. This is a schematic diagram illustrating the diffusion of backlight light by the fine step 15, where Figure 3(a) shows an example where the light divergence angle changes in steps, and Figure 3(b) shows an example where the light divergence angle changes gradually. This is a schematic cross-sectional view illustrating the outline of the image illumination unit 10 according to the second embodiment. This is a schematic diagram illustrating the two-dimensional arrangement of the light-emitting element 12 and the first lens 13 in the image illumination unit 10 according to the third embodiment. This is a schematic diagram illustrating the two-dimensional arrangement of the light-emitting element 12 and the first lens 13 in the image illumination unit 10 according to the fourth embodiment.

[0022] (First Embodiment) Hereinafter, embodiments 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 explanations will be omitted as appropriate. In the following description, an example will be given of the image projection device 100 according to the present invention being applied to a HUD mounted on a vehicle or the like. Figure 1 is a schematic diagram illustrating the projection of virtual images P1 and P2 using the image projection device 100 according to this embodiment. The dashed line shown in Figure 1 is the first image light L, which will be described later. １ The optical path is shown, and the dashed line represents the second image light L. ２ This shows the optical path of the first image light L projected from the image projection device 100. As shown in Figure 1, the first image light L projected from the image projection device 100 １ and the second image light L ２ The light is reflected by the windshield (display unit) WS and projected onto the driver's line of sight. The driver sees the first image light L １ and the second image light L ２ The virtual images P1 and P2, formed on the extension of the incoming optical path, are observed. In this embodiment, the image projection device 100 uses the first image light L １ and the second image light L ２ This example shows how two virtual images P1 and P2 are formed by projecting, but the number of virtual images P1 and P2 is not limited.

[0023] The windshield WS is provided in front of the driver's seat of the vehicle and is a part that transmits visible light. On the inner surface of the windshield WS, the first image light L １ and the second image light L ２ are reflected in the viewpoint direction, and light from outside the vehicle is transmitted in the viewpoint direction. Therefore, it corresponds to the display unit in the present invention. Here, an example using the windshield WS as the display unit is shown, but a combiner may be prepared as the display unit separately from the windshield WS, and the light from the image projection device 100 may be reflected in the viewpoint direction. Further, it is not limited to being located in front of the vehicle, and it may be arranged on the side or rear as long as it projects an image with respect to the viewpoint of the passenger.

[0024] The virtual images P1 and P2 are images displayed as if they are formed in space when the first image light L １ and the second image light L ２ reflected by the windshield WS reach the viewpoint (instrument panel) of the passenger. The positions where the virtual images P1 and P2 are formed are determined by the combined focal length of the projection optical unit included in the image projection device 100 and the windshield WS.

[0025] In the image projection device 100 of the present embodiment, the distant image displayed in the distant display area of the image irradiation unit 10 is irradiated as the first image light L １ and the near image displayed in the near display area is irradiated as the second image light L ２ Examples of the distant image displayed in the distant display area include auxiliary information related to driving such as an image for attracting attention and emergency information. Examples of the near image displayed in the near display area include a speed and volume indicator, a traveling direction guide, and the like.

[0026] Further, as shown in FIG. 1, the image projection device 100 includes an image irradiation unit 10, a first mirror 20, a second mirror 30, and a housing 40. In the image projection device 100, each unit is controlled using a control unit (not shown) that is communicably connected to each unit. The configuration of the control unit is not limited, but examples include those provided with a CPU (Central Processing Unit) for performing information processing, a memory device, a recording medium, an information communication device, and the like. The control unit controls the operation of each unit according to a predetermined program and sends information (image information) including an image to the image irradiation unit 10.

[0027] The image irradiation unit 10 is a part that irradiates light including an image as image light to the first mirror 20 based on the image information from the control unit. In the present embodiment, an example is shown in which two image lights displayed in two image display areas are irradiated to the first mirror 20 as the first image light L １ and the second image light L ２ . Details of the image irradiation unit 10 will be described later.

[0028] The first mirror 20 is an optical member that reflects the first image light L １ and the second image light L ２ that have reached from the image irradiation unit 10 in the direction of the second mirror 30. In the example shown in FIG. 1, the first mirror 20 is shown as a reflecting mirror on a flat plate, but a concave or convex reflecting mirror may be used. Further, when the first mirror 20 is formed of a curved surface, it is not limited to a constant curvature, and a paraboloid of revolution, an ellipsoidal surface, a free-form surface mirror, or the like can be used.

[0029] The second mirror 30 is an optical member that reflects the first image light L １ and the second image light L ２ that have reached from the first mirror 20 in the direction of the windshield WS. In the example shown in FIG. 1, as the second mirror 30, a free-form surface mirror having a concave shape with an optical design necessary for projecting the first image light L １ and the second image light L ２ as virtual images P1 and P2 is shown.

[0030] The reflecting surfaces of the first mirror 20 and the second mirror 30 transmit the first image light L through the windshield WS１ and the second image light L ２ The design is such that the light diameter expands in the direction of the driver's viewpoint in order to project the first image light L as virtual images P1 and P2. Here, expansion of the light diameter in the direction of the viewpoint includes not only cases where the light diameter expands consistently after reflection, but also cases where the light diameter contracts, forms an image at an intermediate point, and then expands. The combination of the first mirror 20 and the second mirror 30 projects the first image light L through the windshield WS. １ and the second image light L ２ It has the function of projecting light and corresponds to the backlight optical unit in this invention.

[0031] In Figure 1, the first image light L １ and the second image light L ２ The optical path is depicted as a single straight line. However, the actual first image light L １ and the second image light L ２ This is displayed in the image illumination unit 10 with a predetermined area, and has a predetermined area in a direction perpendicular to the direction of travel. Also, the first image light L １ and the second image light L ２ The light may travel while being reflected by the first mirror 20, reducing its diameter, and be imaged at an intermediate imaging position F (not shown) between the first mirror 20 and the second mirror 30.

[0032] The housing 40 constitutes the outer shape of the image projection device 100 and is a container that houses each part. The housing 40 contains the first image light L １ and the second image light L ２ A light emission port is provided for emitting light. Furthermore, an angle adjustment unit is provided inside the housing 40 to adjust the angle of the second mirror 30, thereby adjusting the first image light L projected onto the windshield WS. １ and the second image light L ２ The irradiation angle may be adjusted to change the image formation height of the virtual images P1 and P2. Alternatively, the housing 40 may be provided with an optical filter that cuts out ultraviolet and infrared light contained in the light (external light) that arrives from the outside.

[0033] Figure 2 is a schematic cross-sectional view illustrating the outline of the image illumination unit 10 according to this embodiment. As shown in Figure 2, the image illumination unit 10 of this embodiment includes a substrate 11, a light-emitting element 12, a first lens 13, a second lens 14, a microstep 15, and an image display unit 16.

[0034] The substrate portion 11 is a roughly plate-shaped member on which the light-emitting elements 12 are mounted and held. Although not shown in Figure 2, a wiring pattern is formed on the surface of the substrate portion 11, and multiple light-emitting elements 12 are electrically connected to the wiring pattern. A drive circuit that supplies current to the light-emitting elements 12 to drive and control their emission may also be formed on the substrate portion 11. Furthermore, a control unit that controls various parts of the image projection device 100 may be mounted on the substrate portion 11.

[0035] The light-emitting element 12 is a component that illuminates the image display unit 16 with backlight light via the first lens 13 and the second lens 14. Multiple light-emitting elements 12 are arranged two-dimensionally within an arrangement area divided by the long side direction and the short side direction. In the example shown in Figure 2, the left-right direction in the figure corresponds to the long side direction, and the direction perpendicular to the plane of the paper corresponds to the short side direction. The light-emitting element 12 is, for example, a semiconductor light-emitting element such as an LED (Light Emitting Diode), and is also arranged two-dimensionally on the substrate 11 in the depth direction of the paper in Figure 2. The light-emitting color of the light-emitting element 12 is not particularly limited, but in this embodiment, it is white as an example. Furthermore, the light-emitting element 12 is not limited to an LED, but may also be a semiconductor laser or an organic EL (Electroluminescence) element, etc.

[0036] The first lens 13 is an optical component positioned in the light emission direction of the plurality of light-emitting elements 12, and has the function of focusing the backlight light irradiated from the light-emitting elements 12 and emitting light at a predetermined divergence angle. The plurality of first lenses 13 are each provided corresponding to the plurality of light-emitting elements 12, and are arranged two-dimensionally within an arrangement area divided by the long side direction and the short side direction. The material constituting the first lens 13 is not limited, and for example, resins such as acrylic resin, glass, etc. can be used.

[0037] In the example shown in Figure 2, a bullet-shaped convex lens structure is shown as an example of the first lens 13, but the shape is not limited. Here, the divergence angle of the first lens 13 refers to the angle of spread of light from parallel light, where the divergence angle of parallel light is 0 degrees, and the divergence angle when the light spreads at an angle of 10 degrees from parallel light is 10 degrees. In Figure 2, the first lens 13 shows the case where the backlight light is emitted as parallel light, or light that is close to parallel light (hereinafter, both are collectively referred to as "approximately parallel light").

[0038] The second lens 14 is positioned between the first lens 13 and the image display unit 16, and is an optical element that adjusts the light distribution of the backlight light irradiated from the multiple first lenses 13 and irradiates the image display unit 16 with it. The material constituting the second lens 14 is not limited, and for example, resins such as acrylic resin, glass, etc. can be used. In the example shown in Figure 2, the light incident surface side of the second lens 14 has a curved concave lens shape that is thinner in the center and thicker on both sides in the left-right direction in the figure. In addition, a plurality of fine steps 15 are formed on the light emission surface of the second lens 14. Therefore, the backlight light incident on the second lens 14 is amplified in the left-right direction in the figure by the second lens 14 and irradiates the image display unit 16.

[0039] The microsteps 15 are a plurality of uneven shapes provided on the second lens 14, and each of these uneven shapes has the function of scattering backlight light. The material constituting the microsteps 15 is not limited, and for example, resins such as acrylic resin, glass, etc. can be used. The microsteps 15 may be formed integrally with the second lens 14, or they may be formed separately and bonded to the second lens 14. The shape of the microsteps 15 is not limited, but it is preferable that the components of the backlight light are scattered in the direction of the long side (left and right direction in the figure) of the display area of ​​the image display unit 16. It is also preferable that the microsteps 15 be arranged two-dimensionally so as to scatter the components of the backlight light in the direction of the short side (direction perpendicular to the paper plane) of the display area of ​​the image display unit 16. Figure 2 shows an example in which the microsteps 15 are provided on the light emission side, but the microsteps 15 may also be provided on the light incidence side. Also in Figure 2, an example is shown in which fine concave shapes are repeatedly provided as the microsteps 15, but the shape and size are not limited.

[0040] The image display unit 16 functions as a spatial light modulation unit, receiving backlight light emitted from the light-emitting element 12 from the back and emitting light modulated by image information from the output surface. The specific configuration of the image display unit 16 is not limited, but as an example, a transmissive liquid crystal display device that transmits light incident from the back and emits it from the front can be used.

[0041] The image display unit 16 includes a display area that is a portion of the total display area, where an image is actually displayed, when the total display area is defined as the entire area where an image can be displayed. In this embodiment, the backlight light from the light-emitting element 12 is irradiated onto the display area of ​​the image display unit 16, and the backlight light may not be irradiated onto the non-display area of ​​the total display area where an image is not actually displayed. The image display unit 16 may also be provided with a light-shielding mask (not shown) having an opening corresponding to the display area on the incident side of the backlight light or the outgoing side of the image light.

[0042] As shown by the arrows in Figure 2, in the image illumination unit 10, the backlight light emitted from the light-emitting element 12 is refracted by the first lens 13 and the second lens 14, respectively, diffused by the fine step 15, and illuminated on the back of the image display unit 16. As a result, the image displayed in the display area of ​​the image display unit 16 is illuminated by the backlight light emitted from the light-emitting element 12, and the first image light L １ or second image light L ２ The light is emitted as follows. At this time, the backlight light is made into approximately parallel light by the first lens 13, the light distribution is adjusted by the second lens 14, and it is diffused by the fine step 15. As a result, the backlight light is uniformly irradiated onto the display area of ​​the image display unit 16.

[0043] Figure 3 is a schematic diagram illustrating the diffusion of backlight light by the fine steps 15. Figure 3(a) shows an example where the light divergence angle changes in steps, and Figure 3(b) shows an example where the light divergence angle changes gradually. The upper part of Figures 3(a) and (b) schematically shows the size of the fine steps 15 along the long side direction in the display area of ​​the image display unit 16. The lower part of Figures 3(a) and (b) shows the divergence angle of the fine steps 15 along the long side direction in the display area of ​​the image display unit 16. As shown in Figures 3(a) and (b), the curvature of the fine steps 15 is relatively small at the center of the long side direction of the display area and relatively large at the edges. As a result, the divergence angle of the fine steps 15 is relatively large at the center of the long side direction of the display area and relatively small at the edges.

[0044] When multiple light-emitting elements 12 are arranged in a high-density two-dimensional array, the backlight light emitted from each light-emitting element 12 overlaps, resulting in a tendency for the light intensity to be higher near the center of the arrangement area where the light-emitting elements 12 are located, and relatively lower at the periphery. However, in this embodiment, the backlight distribution is adjusted by the second lens 14, and further diffusion is achieved by distributing the curvature of the fine step 15. This makes it possible to reduce the backlight light irradiated to the center of the long side direction in the display area of ​​the image display unit 16, increase the backlight light irradiated to the edges, and equalize the brightness distribution.

[0045] As described above, in the image projection device 100 of this embodiment, the second lens 14 is provided with a plurality of fine steps 15, and the divergence angle of the backlight light is large in the center in the direction of the long side, and small at the edges, so that a plurality of light-emitting elements 12 can be arranged at high density to increase brightness while making the brightness distribution uniform.

[0046] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figure 4. Details that overlap with the first embodiment will be omitted from the description. Figure 4 is a schematic cross-sectional view illustrating the outline of the image irradiation unit 10 according to this embodiment. As shown in Figure 4, the image irradiation unit 10 of this embodiment includes a substrate 11, a light-emitting element 12, and first lenses 13a and 13b. In Figure 4, the second lens 14, the microstep 15, and the image display unit 16 are omitted from the illustration.

[0047] The first lens 13a is positioned near the end in the long-side direction in the arrangement region where the multiple light-emitting elements 12 are arranged two-dimensionally. The first lens 13b is positioned near the center in the long-side direction in the arrangement region where the multiple light-emitting elements 12 are arranged two-dimensionally. Furthermore, the curvature of the first lens 13a is relatively smaller than the curvature of the first lens 13b. Therefore, as indicated by the arrows in Figure 4, the divergence angle of the backlight light is relatively larger for the first lens 13b than for the first lens 13a.

[0048] This makes it possible to reduce the backlight light illuminating the center of the long side of the display area of ​​the image display unit 16, increase the backlight light illuminating the edges, and make the brightness distribution more uniform.

[0049] As described above, in the image projection device 100 of this embodiment, the multiple first lenses 13 have a large divergence angle of backlight light at the center in the long side direction and a small divergence angle of backlight light at the ends. Therefore, it is possible to increase the brightness by arranging multiple light-emitting elements 12 at high density while making the brightness distribution uniform.

[0050] (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 illustrating the two-dimensional arrangement of the light-emitting element 12 and the first lens 13 in the image irradiation unit 10 according to this embodiment.

[0051] As shown in Figure 5, the multiple light-emitting elements 12 and the first lens 13 are arranged two-dimensionally within the arrangement region. The light-emitting elements 12 are positioned corresponding to the center position of the first lens 13. In Figure 5, the outer shape of the first lens 13 is shown as a circle, but it actually has a curved shape such as a paraboloid of revolution, and the overlapping parts of adjacent circles actually form a boundary where the curved surfaces contact each other in a valley-like manner. Also, Figure 5 shows an example in which there is a region that is not included in the circle of the first lens 13, but the diameter may be such that there is no gap between adjacent circles.

[0052] The x-axis and y-axis directions shown in Figure 5 correspond to the long and short sides of the arrangement area where multiple light-emitting elements 12 are arranged, respectively. The x-axis and y-axis directions also correspond to the long and short sides of the display area of ​​the image display unit 16. In the example shown in Figure 5, the light-emitting elements 12 are arranged in three rows along the a direction parallel to the x-axis, but the number of rows is not limited. Furthermore, the light-emitting elements 12 are arranged with their x-axis positions shifted along the b direction, which is different from the y-axis direction by a predetermined angle θ, so that adjacent light-emitting elements 12 are positioned at the vertices of a triangle, and this arrangement is repeated two-dimensionally.

[0053] Because the arrangement of the light-emitting elements 12 is a two-dimensional repeating triangular shape, the mounting density of the light-emitting elements 12 within the arrangement area cut out in the long and short sides can be increased compared to arranging them in a rectangular shape. This makes it possible to increase the brightness of the backlight light illuminating the display area of ​​the image display unit 16.

[0054] The predetermined angle θ is not limited, but it is preferably in the range of 15 degrees to 45 degrees. Furthermore, it is preferable that the triangle formed by adjacent light-emitting elements 12 as vertices be an isosceles triangle with the longer side (x-axis direction) as the base and the shorter side (y-axis direction) as the height. This allows the light-emitting elements 12 arranged in multiple rows to be arranged symmetrically in the x-axis direction, thereby improving the uniformity of the backlight.

[0055] Furthermore, it is even more preferable that the predetermined angle θ is less than 30 degrees. When the predetermined angle θ is less than 30 degrees, the mounting density of the light-emitting elements 12 in the x-axis direction is greater than that in the y-axis direction. This makes it possible to make the brightness of the display area uniform even when the backlight light is diverted in the x-axis direction by the first lens 13, the second lens 14, and the fine step 15.

[0056] As described above, in the image projection device 100 of this embodiment, multiple light-emitting elements 12 are arranged two-dimensionally within an arrangement area divided by the long side direction and the short side direction, along a direction along the long side direction and a direction different by a predetermined angle θ from the short side direction. Therefore, it is possible to increase the brightness by arranging multiple light-emitting elements 12 at high density while making the brightness distribution uniform.

[0057] (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to Figure 6. Details that overlap with the third embodiment will be omitted from the explanation. Figure 6 is a schematic diagram illustrating the two-dimensional arrangement of the light-emitting element 12 and the first lens 13 in the image irradiation unit 10 according to this embodiment.

[0058] As shown in Figure 6, the multiple light-emitting elements 12 and the first lens 13 are arranged two-dimensionally within the arrangement region. The light-emitting elements 12 are also positioned corresponding to the center position of the first lens 13. In Figure 6, the outer shape of the first lens 13 is shown as an oval, but it actually has a curved shape such as a paraboloid of revolution, and the overlapping parts of adjacent ovals actually form a boundary where the curved surfaces contact each other in a valley-like manner.

[0059] As shown in the rectangular shape in Figure 6, the horizontal and vertical directions in the figure correspond to the long and short sides of the arrangement area where multiple light-emitting elements 12 are arranged, respectively. The long and short sides of the arrangement area also correspond to the long and short sides of the display area of ​​the image display unit 16, respectively. In the example shown in Figure 6, the light-emitting elements 12 are arranged in two rows along the long side, but the number of rows is not limited. Furthermore, the light-emitting elements 12 are arranged with their positions along the long side in each row offset, and an arrangement in which adjacent light-emitting elements 12 are located at the vertices of an isosceles triangle is repeated two-dimensionally.

[0060] The first lens 13 has an elliptical surface in a plan view, with the long side of the arrangement area as the minor axis and the short side as the major axis. In the example shown in Figure 6, the light-emitting surface of the first lens 13 has a curvature in the short side direction that is greater than that in the long side direction, and a divergence angle in the short side direction that is greater than that in the long side direction. However, the curvature in the long and short sides may be the same, and only the lengths of the major and minor axes may be changed. Therefore, the backlight light emitted from the light-emitting element 12 is amplified in the long side direction and reaches the second lens 14. The light-emitting element 12 is arranged to form an isosceles triangle with the long side as the base and the short side as the height, so the density in the long side direction is higher than in the short side direction.

[0061] Therefore, in the placement area, the backlight light from the light-emitting element 12 is irradiated at high density in the direction of the longer side, but the divergence angle in the direction of the longer side increases at the oval first lens 13. As a result, the backlight light, which is also amplified in the direction of the longer side at the second lens 14, is uniformly irradiated onto the display area of ​​the image display unit 16.

[0062] In the image projection device 100 of this embodiment, multiple light-emitting elements 12 are arranged two-dimensionally within an arrangement area divided by the long side direction and the short side direction, along a direction along the long side direction and a direction different by a predetermined angle θ from the short side direction. This makes it possible to increase brightness by arranging multiple light-emitting elements 12 at high density while making the brightness distribution uniform.

[0063] (Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. Details that overlap with the first to fourth embodiments will be omitted from the description. In this embodiment, the area of ​​the arrangement region in which the light-emitting elements 12 are arranged two-dimensionally is smaller than the entire display area of ​​the image display unit 16, and the backlight is irradiated onto the display area.

[0064] In the image projection device 100 of this embodiment, multiple light-emitting elements 12 are arranged two-dimensionally in an arrangement area smaller than the entire display area, and backlight light is irradiated onto the display area, which is a part of the entire display area. At this time, by arranging the light-emitting elements 12 two-dimensionally in directions that differ by a predetermined angle θ from the long side direction and the short side direction, an appropriate light distribution can be set. Furthermore, by using a first lens 13 that is an ellipse with a minor axis in the long side direction and a major axis in the short side direction, the divergence angle in the long side direction can be increased, and backlight light can be irradiated uniformly. In addition, by making the divergence angle of the fine step 15 large in the center in the long side direction and small at the edges, the overlap of backlight light from the light-emitting elements 12 near the center can be appropriately diffused, and backlight light can be irradiated uniformly.

[0065] 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.

[0066] This international application claims priority based on Japanese Patent Application No. 2024-162535, filed on 19 September 2024, and the entire contents of said Japanese Patent Application No. 2024-162535 are incorporated herein by reference.

[0067] The above description of specific embodiments of the present invention is provided for illustrative purposes only. It is not intended to be exhaustive or to limit the invention to the forms described. Numerous modifications and changes are possible in light of the above description, as will be obvious to those skilled in the art.

[0068] 100...Image projection device 10...Image illumination unit 20...First mirror 30...Second mirror 40...Housing 11...Substrate unit 12...Light-emitting element 13, 13a, 13b...First lens 14...Second lens 15...Fine step 16...Image display unit

Claims

1. An image projection device comprising: an image display unit having a display area set in a part of the entire display area for displaying an image; a plurality of light-emitting elements that irradiate the image display unit with backlight light; and a plurality of first lenses provided corresponding to the plurality of light-emitting elements, wherein the plurality of light-emitting elements are arranged two-dimensionally within an arrangement area divided by the long side direction and the short side direction, along a direction along the long side direction and a direction different by a predetermined angle from the short side direction.

2. An image projection device according to claim 1, characterized in that the predetermined angle is in the range of 15 degrees or more and 45 degrees or less.

3. An image projection device according to claim 2, wherein the plurality of light-emitting elements are arranged to form an isosceles triangle with the longer side as the base and the shorter side as the height, and the predetermined angle is less than 30 degrees.

4. An image projection device according to claim 1, wherein the first lens has an elliptical surface with the long side direction as the minor axis and the short side direction as the major axis.

5. An image projection device according to claim 1, wherein the first lens has a large divergence angle of the backlight light at the center in the direction of the long side and a small divergence angle of the backlight light at the ends.

6. An image projection apparatus according to claim 1, comprising a second lens for adjusting the light distribution of the backlight light emitted from the first lens, wherein the second lens is provided with a plurality of fine steps, and the divergence angle of the backlight light is large at the center in the direction of the long side and small at the ends.

7. An image projection device comprising: an image display unit having a display area set in a part of the entire display area for displaying an image; a plurality of light-emitting elements that irradiate the image display unit with backlight light; and a plurality of first lenses provided corresponding to the plurality of light-emitting elements, wherein the plurality of light-emitting elements are arranged within an arrangement area divided by the long side direction and the short side direction, and the first lenses are characterized in that the divergence angle of the backlight light is large at the center in the long side direction and small at the ends.

8. An image projection device comprising: an image display unit having a display area set in a part of the entire display area for displaying an image; a plurality of light-emitting elements that irradiate the image display unit with backlight light; a plurality of first lenses provided corresponding to the plurality of light-emitting elements; and a second lens that adjusts the light distribution of the backlight light emitted from the first lenses, wherein the plurality of light-emitting elements are arranged within an arrangement area divided by the long side direction and the short side direction, the second lens is provided with a plurality of fine steps, and the divergence angle of the backlight light is large at the center in the long side direction and small at the ends.

9. An image projection device according to any one of claims 1 to 8, characterized in that the area of ​​the arrangement area is smaller than the total display area, and the backlight light is irradiated onto the display area.

Images