Optical system, illumination system, display system, and moving body

Abstract

The present disclosure provides an optical system, an illumination system, a display system, and a moving body. The optical system (100) includes a light guide member (1) and a plurality of prismatic sheets (3). The light guide member (1) has an incident surface (10) on which light is incident, and a first surface (11) and a second surface (12) that face each other, the second surface being a light exit surface. The plurality of prismatic sheets (3) are arranged on the first surface and reflect light that has passed through the inside of the light guide member (1) toward the second surface. The plurality of prismatic sheets (3) include two or more prismatic sheets (3) whose inclination angles (θ10) with respect to the incident surface differ depending on positions in a first direction along both the incident surface and the first surface. In the plurality of prismatic sheets (3), the inclination angles (θ10) of the two or more prismatic sheets (3) are determined such that the closer the position is to both ends of the first direction near the first surface, the more the light that exits from the second surface (12) is directed toward the outside or the inside of the first direction with respect to a reference light line (L100).

Description

Technical Field

[0001] This disclosure generally relates to optical systems, illumination systems, display systems, and moving bodies. More specifically, this disclosure relates to optical systems, illumination systems, display systems, and moving bodies that control light incident from an incident surface and causing it to exit from an exiting surface. Background Technology

[0002] Patent Document 1 discloses an image display device (display system) that projects a virtual image into an object space. This image display device is an automotive HUD (Head-Up Display) device. The projected light, which serves as the image light, emitted from the automotive HUD device (optical system) within the dashboard is reflected by the windshield and directed towards the driver, who is the visual observer. Thus, the user (driver) can visually recognize images such as navigation images as virtual images and perceive that the virtual image overlaps with a background such as the road surface.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-142491 Summary of the Invention

[0006] One aspect of this disclosure relates to an optical system comprising a light guide member and a plurality of prism sheets. The light guide member has an incident surface for light incidence and opposing first and second surfaces, the second surface being a light exit surface. The plurality of prism sheets are disposed on the first surface and reflect light passing through the interior of the light guide member toward the second surface. The plurality of prism sheets includes at least two prism sheets whose tilt angles relative to the incident surface differ depending on their positions along a first direction of both the incident surface and the first surface. Among the plurality of prism sheets, the tilt angles of the two or more prism sheets are determined such that the closer they are to the ends of the first surface in the first direction, the more the light emitted from the second surface is directed toward the outer or inner side of the first direction relative to a reference ray. Attached Figure Description

[0007] Figure 1A This is a cross-sectional view showing an outline of the optical system involved in Embodiment 1.

[0008] Figure 1B It is Figure 1A The diagram of region A1 is enlarged.

[0009] Figure 2A This is a top view of the aforementioned optical system.

[0010] Figure 2B This is the front view of the aforementioned optical system.

[0011] Figure 2C This is a bottom view of the aforementioned optical system.

[0012] Figure 2D This is a side view of the aforementioned optical system.

[0013] Figure 3A This is a perspective view showing the outline of the aforementioned optical system.

[0014] Figure 3B This is a perspective view showing the outline of the optical system involved in the comparative example.

[0015] Figure 4 This is an explanatory diagram of a display system that uses the aforementioned optical system.

[0016] Figure 5 This is an explanatory diagram of a mobile body equipped with the aforementioned display system.

[0017] Figure 6A It is Figure 2C The schematic top view of area A1 is enlarged.

[0018] Figure 6B It is Figure 6A The schematic top view of area A1 is enlarged.

[0019] Figure 6C It is Figure 6A Area A2 is an enlarged schematic top view.

[0020] Figure 6D It is Figure 6A The diagram in area A3 is an enlarged schematic top view.

[0021] Figure 7A It is Figure 2C The schematic top view of area A1 is enlarged.

[0022] Figure 7B yes Figure 7A Sectional view along line A1-A1.

[0023] Figure 7C yes Figure 7A Sectional view along line B1-B1.

[0024] Figure 8 This is a schematic top view of the optical system involved in the first variation of Embodiment 1.

[0025] Figure 9 This is a schematic top view of the optical system involved in the second variation of Embodiment 1.

[0026] Figure 10This is a schematic bottom view of an optical system involved in another variation of Embodiment 1.

[0027] Figure 11A This is a schematic top view of the optical system involved in Embodiment 2.

[0028] Figure 11B It is Figure 11A The diagram shows an enlarged schematic top view of area A1.

[0029] Figure 11C It is Figure 11A Enlarged schematic top views of areas A2 and A3.

[0030] Figure 11D It is Figure 11A The schematic top view in area A4 is enlarged.

[0031] Figure 12 This is a schematic top view of the optical system involved in a variation of Embodiment 2.

[0032] Figure 13 This is a schematic top view of the optical system involved in Embodiment 3.

[0033] Figure 14A This is a schematic top view of the optical system involved in a variation of Embodiment 3.

[0034] Figure 14B This is a schematic top view of the optical system involved in a variation of Embodiment 3.

[0035] Figure 15A This is a schematic top view of the optical system involved in a variation of Embodiment 3.

[0036] Figure 15B This is a schematic top view of the optical system involved in a variation of Embodiment 3.

[0037] Figure 16 This is a perspective view showing the outline of the optical system involved in Embodiment 4.

[0038] Figure 17A This is a schematic top view of the aforementioned optical system.

[0039] Figure 17B It is Figure 17A The diagram shows an enlarged schematic top view of area A1.

[0040] Figure 17C It is Figure 17A Area A2 is an enlarged schematic top view.

[0041] Figure 17D It is Figure 17A The diagram in area A3 is an enlarged schematic top view.

[0042] Symbol explanation:

[0043] 1: Light guide component;

[0044] 3. 3A~3I: Prism sheets;

[0045] 4: Light source;

[0046] 5: Monitor;

[0047] 6. 6A~6D: Long strip prism;

[0048] 10: Incident surface;

[0049] 11: Page 1;

[0050] 12: Page 2;

[0051] 100, 100A~100I: Optical system;

[0052] 200: Lighting system;

[0053] 300: Display system;

[0054] B1: Moving body;

[0055] B11: Main body of the moving object;

[0056] L1: Direct optical path;

[0057] L100: Reference ray;

[0058] Va1: Imaginary arc;

[0059] Vg1: Imaginary grid;

[0060] θ10: Inclination angle. Detailed Implementation

[0061] (Implementation Method 1)

[0062] (1) Summary

[0063] First, refer to Figures 1A to 3B An overview of the optical system 100 and the illumination system 200 using the optical system 100 according to this embodiment will be described.

[0064] The optical system 100 involved in this embodiment (refer to) Figure 1A as well as Figure 1B It has the function of controlling the light incident from the incident surface 10 so that it exits from the exit surface (second surface 12). For example... Figure 1A as well as Figure 1BAs shown, the optical system 100 includes a light guide component 1 and multiple prism sheets 3.

[0065] The optical system 100 and the light source 4 together constitute the illumination system 200. In other words, the illumination system 200 according to this embodiment includes the optical system 100 and the light source 4. The light source 4 outputs light incident on the incident surface 10. As will be described in detail later, when the optical system 100 includes a light control unit 2, the light from the light source 4 does not directly incident on the light guide member 1, but passes through the light control unit 2 and then incident on the light guide member 1. That is, the light source 4 passes through the light control unit 2 and emits light onto the incident surface 10 (of the light guide member 1).

[0066] Thus, in this embodiment, the optical system 100 includes a light control unit 2 in addition to the light guide member 1 and the plurality of prism sheets 3. The light control unit 2 is located between the light source 4 and the incident surface 10 of the light guide member 1, and controls the light output from the light source 4 and incident on the incident surface 10. Specifically, in this embodiment, the light guide member 1 and the light control unit 2 are integrally molded. That is, in this embodiment, the light guide member 1 and the light control unit 2 are integrally molded and inseparable. In other words, the light control unit 2 is seamlessly continuous with respect to the incident surface 10 of the light guide member 1, and the light guide member 1 and the light control unit 2 are seamlessly integrated. Therefore, in this embodiment, the incident surface 10 in the light guide member 1 is an "imaginary surface" defined inside the integrally molded light guide member 1 and the light control unit 2, and does not have a physical form.

[0067] In this embodiment, the light guide member 1 has an incident surface 10 for light incidence and a first surface 11 and a second surface 12 facing each other. The second surface 12 is the light emission surface. A plurality of prism sheets 3 are disposed on the first surface 11. The plurality of prism sheets 3 reflect light passing through the interior of the light guide member 1 toward the second surface 12.

[0068] Here, the light guide component 1 includes a direct optical path L1 (refer to...) Figure 1A as well as Figure 1B The direct light path L1 is a light path in which light incident from the incident surface 10 is directly reflected by any one of the multiple prism sheets 3, causing it to exit from the second surface 12. Furthermore, the light guide member 1 includes a light path (direct light path L1) that allows light incident from the incident surface 10 into the light guide member 1 to exit from the second surface 12 within the light guide member 1 through only one reflection by any one of the prism sheets 3. If light passing through the direct light path L1 is incident from the incident surface 10 into the light guide member 1, it is not reflected by components other than the prism sheets 3, but reaches the second surface 12 through only one reflection by the prism sheets 3, and exits directly from the second surface 12 into the light guide member 1.

[0069] In this embodiment, most of the light incident from the incident surface 10 onto the light guide member 1 and emitted from the second surface 12 is guided inside the light guide member 1 through the direct optical path L1. Therefore, in this embodiment, most of the light incident from the incident surface 10 onto the light guide member 1 is not reflected by components other than the prism sheet 3, and is emitted from the second surface 12 to the outside of the light guide member 1 only after being reflected once by the prism sheet 3. As a result, the light extraction efficiency of the optical system 100 can be improved.

[0070] Thus, as Figure 1A as well as Figure 1B As shown, the optical system 100 according to this embodiment includes a light guide member 1 and a plurality of prism sheets 3. Furthermore, as described above, the light guide member 1 has an incident surface 10 for light incidence and a first surface 11 and a second surface 12 facing each other. The second surface 12 is the light exit surface. A plurality of prism sheets 3 are disposed on the first surface 11. The plurality of prism sheets 3 reflect light passing through the interior of the light guide member 1 toward the second surface 12. Here, as... Figures 6A to 6D As shown, the plurality of prism sheets 3 includes at least two prism sheets 3 whose tilt angle θ10 relative to the incident surface 10 varies depending on their position along the first direction (X-axis direction) of both the incident surface 10 and the first surface 11. Among the plurality of prism sheets 3, the tilt angle θ10 of the two or more prism sheets 3 is determined such that the closer they are to the two ends in the first direction of the first surface 11, the more the light emitted from the second surface 12 is directed towards the outside or inside of the first direction relative to the reference ray L100.

[0071] According to this method, light incident from the incident surface 10 passes through the interior of the light guide member 1, is reflected by a plurality of prism sheets 3 disposed on the first surface 11 of the light guide member 1, and is emitted from the second surface 12, which serves as the emission surface of the light guide member 1. Here, the tilt angle θ10 of two or more of the plurality of prism sheets 3 relative to the incident surface 10 varies at least according to their positions in the first direction (X-axis direction), and the direction of the light emitted from the second surface 12 is controlled by their tilt angle θ10. Moreover, the tilt angle θ10 is determined such that the closer the prism sheet 3 is to the two ends in the first direction of the first surface 11, the more the light emitted from the second surface 12 is directed towards the outside or inside of the first direction relative to the reference ray L100. Therefore, the light emitted from the second surface 12, which serves as the emission surface, is not emitted in the same direction from the entire area of ​​the second surface 12, but rather, the closer the position is to the two ends in the first direction of the second surface 12, the more it is directed towards the outside or inside of the reference ray L100. As a result, the optical system 100 according to this embodiment has the advantage that the brightness distribution in the second surface 12, which is the emission surface, can be adjusted by the tilt angle θ10 of the plurality of prism sheets 3, and the desired brightness distribution can be easily achieved.

[0072] (2) Details

[0073] The following is for reference Figures 1A to 7C The optical system 100, the illumination system 200 using the optical system 100, the display system 300 using the illumination system 200, and the moving body B1 involved in this embodiment will be described in detail.

[0074] (2.1) Prerequisites

[0075] In the following description, the width direction of the light guide member 1 (in...) Figure 3A The direction of the multiple light sources 4 arranged in the middle is set as the "X-axis direction", and the depth direction of the light guide component 1 (in the middle) is set as the "X-axis direction". Figure 1A The direction in which the optical axis Ax1 extends is defined as the "Y-axis direction". Furthermore, in the following description, the thickness direction of the light guide member 1 (where...) is... Figure 1A The direction in which the first surface 11 and the second surface 12 are arranged is designated as the "Z-axis direction". The X, Y, and Z axes of these directions are defined as orthogonal to each other. The arrows in the attached diagram representing the "X-axis direction", "Y-axis direction", and "Z-axis direction" are for illustrative purposes only and do not constitute a physical entity. The X-axis direction is along both the incident surface 10 and the first surface 11, and is therefore equivalent to the "first direction". Furthermore, the Y-axis direction is orthogonal to the first direction (X-axis direction) within the second surface 12, and is therefore equivalent to the "second direction".

[0076] Furthermore, the "extraction efficiency" mentioned in this disclosure refers to the proportion of light emitted from the second surface 12 (emission surface) of the light guide member 1 relative to the amount of light incident on the incident surface 10 of the light guide member 1. That is, if the relative ratio of the amount of light emitted from the second surface 12 of the light guide member 1 to the amount of light incident on the incident surface 10 of the light guide member 1 increases, the light extraction efficiency becomes higher. As an example, if the amount of light incident on the incident surface 10 of the light guide member 1 is "100", and the amount of light emitted from the second surface 12 of the light guide member 1 is "10", then the light extraction efficiency in the light guide member 1 becomes 10%.

[0077] Furthermore, the term "optical axis" as used in this disclosure refers to an imaginary ray that represents the beam of light passing through the entire system. As an example, the optical axis of light source 4 coincides with the rotational symmetry axis of the light emitted from light source 4.

[0078] Furthermore, the term "parallel" as used in this disclosure means that the two are approximately parallel, that is, in addition to the case where the two are strictly parallel, it also refers to a relationship in which the angle between the two converges to a range of several degrees (e.g., less than 5 degrees).

[0079] Furthermore, the term "orthogonal" as used in this disclosure means that the two are approximately orthogonal, that is, in addition to the case where the two are strictly orthogonal, it also refers to the relationship in which the angle between the two converges to a range of degrees (e.g., less than 5 degrees) with 90 degrees as the reference.

[0080] (2.2) Display System

[0081] First, refer to Figure 4 as well as Figure 5 The display system 300 and the movable body B1 involved in this embodiment will be described.

[0082] like Figure 4 As shown, the lighting system 200 and the display 5 together constitute a display system 300 according to this embodiment. In other words, the display system 300 according to this embodiment includes a lighting system 200 and a display 5. The display 5 receives light emitted from the lighting system 200 to display an image. Here, "image" refers to an image displayed by a user U1 (refer to...). Figure 5 Images displayed in a visually recognizable manner can be graphics, symbols, text, numbers, photographs, or combinations thereof. Images displayed by the display system 300 include moving images (moving pictures) and still images (still pictures). Furthermore, "moving images" include images composed of multiple still images obtained through time-lapse photography or the like.

[0083] In addition, such as Figure 5 As shown, the display system 300 and the mobile body B11 together constitute a mobile body B1, such as a car. In other words, the mobile body B1 according to this embodiment includes the display system 300 and the mobile body B11. The display system 300 is mounted on the mobile body B11. In this embodiment, as an example, the mobile body B1 is set as a car (passenger vehicle) driven by a person. In this case, the user U1 who visually recognizes the image displayed by the display system 300 is a passenger of the mobile body B1. In this embodiment, as an example, it is assumed that the driver of the car that is the mobile body B1 is the user U1.

[0084] In this embodiment, the display system 300 is, for example, a head-up display (HUD) mounted on the mobile body B1. The display system 300 is used, for example, to display driving support information associated with the mobile body B1, such as speed information, status information, and driving information, in the user U1's field of vision. Driving information for the mobile body B1 includes, for example, navigation-related information such as displaying the driving route, and ACC (Adaptive Cruise Control)-related information that maintains a constant driving speed and inter-vehicle distance.

[0085] like Figure 4 as well as Figure 5 As shown, the display system 300 includes an image display unit 310, an optical system 320, and a control unit 330. Furthermore, the display system 300 also includes a housing 340 that houses the image display unit 310, the optical system 320, and the control unit 330.

[0086] The housing 340 is made of, for example, a molded synthetic resin. An image display unit 310, an optical system 320, and a control unit 330 are housed within the housing 340. The housing 340 is mounted on the dashboard B13 of the main body B11. Light reflected by the second reflector 322 of the optical system 320 (described later) passes through an opening on the upper surface of the housing 340 and is emitted towards the reflective member (windshield B12). The light reflected by the windshield B12 is focused within the eye box C1. The reflective member is not limited to the windshield B12; for example, it can be implemented using a synthesizer or the like mounted on the dashboard B13 of the main body B11.

[0087] According to such a display system 300, the user U1 visually recognizes a virtual image projected onto the space in front of the moving body B1 (outside the vehicle) over the windshield B12. The term "virtual image" as used in this disclosure refers to an image formed by light emitted from the display system 300 and reflected by a reflective member such as the windshield B12, appearing as if it were an actual object. Therefore, the user U1 driving the moving body B1 visually recognizes the image projected by the display system 300 as a virtual image, overlapping with the real space extending in front of the moving body B1. In summary, the display system 300 of this embodiment displays virtual images as images. The images (virtual images) that the display system 300 can display include a virtual image E1 superimposed along the driving surface D1 of the moving body B1, and a virtual image drawn three-dimensionally along a plane PL1 orthogonal to the driving surface D1.

[0088] The image display unit 310 includes a display 5 and an illumination system 200 including an optical system 100. The display 5, such as a liquid crystal display, receives light emitted from the illumination system 200 to display an image. That is, the illumination system 200 emits light from behind the display 5 toward the display 5, and the light from the illumination system 200 passes through the display 5, thereby displaying an image. In other words, the illumination system 200 functions as a backlight for the display 5.

[0089] The image display unit 310 includes a housing 311. The housing 311 houses an illumination system 200 including an optical system 100 and a light source 4, and a display 5. The illumination system 200 and the display 5 are held in the housing 311. Here, the display 5 is positioned along the upper surface of the housing 311, with one side of the display 5 exposed from the upper surface of the housing 311. The illumination system 200 is positioned below the display 5 within the housing 311 and outputs light from below the display 5 towards it. Thus, the upper surface of the housing 311 forms a display surface 312 for displaying images.

[0090] The image display unit 310 is housed inside the housing 340 with its display surface 312 facing the first reflector 321 (described later). The display surface 312 of the image display unit 310 has a shape (e.g., rectangular) that matches the range of the image projected onto the user U1, i.e., the shape of the windshield B12. Multiple pixels are arranged in an array on the display surface 312 of the image display unit 310. The multiple pixels of the image display unit 310 emit light under the control of the control unit 330, and an image is displayed on the display surface 312 by the light emitted from the display surface 312 of the image display unit 310.

[0091] The image displayed on the display surface 312 of the image display unit 310 is projected onto the windshield B12, and the light reflected by the windshield B12 is focused within the visual field C1. That is, the image displayed on the display surface 312 is visually recognized by the user U1 whose viewpoint is within the visual field C1 through the optical system 320. At this time, the user U1 visually recognizes the virtual image projected in the space in front of the moving body B1 (outside the vehicle) beyond the windshield B12.

[0092] The optical system 320 focuses the light emitted from the display surface 312 of the image display unit 310 within the visual range C1. In this embodiment, the optical system 320 includes, for example, a first reflecting mirror 321 as a convex mirror, a second reflecting mirror 322 as a concave mirror, and a windshield B12.

[0093] The first reflector 321 reflects the light output from the image display unit 310 and directs it to the second reflector 322. The second reflector 322 reflects the light incident from the first reflector 321 toward the windshield B12. The windshield B12 reflects the light incident from the second reflector 322 and directs it into the field of vision C1.

[0094] The control unit 330 receives detection signals from various sensors mounted on the main body B11 of the mobile body, for example. Based on the detection signals input from the sensors, image data for displaying a virtual image of the display object is generated. The control unit 330 outputs the generated image data to the image display unit 310, so that an image based on the image data is displayed on the display surface 312 of the image display unit 310. By projecting the image displayed on the display surface 312 onto the windshield B12, the image (virtual image) is displayed by the display system 300. In this way, the image (virtual image) displayed by the display system 300 is visually recognized by the user U1.

[0095] (2.3) Optical System

[0096] Next, refer to Figures 1A to 3B as well as Figures 6A to 6D The optical system 100 will be described.

[0097] As described above, the optical system 100 includes a light guide member 1 and a plurality of prism sheets 3. Furthermore, in this embodiment, the optical system 100, in addition to the light guide member 1 and the plurality of prism sheets 3, also includes a plurality of light control units 2. That is, the optical system 100 according to this embodiment includes a light guide member 1, a plurality of light control units 2, and a plurality of prism sheets 3.

[0098] Furthermore, in this embodiment, the optical system 100 together with the plurality of light sources 4 constitutes the illumination system 200. That is, the illumination system 200 according to this embodiment includes the optical system 100 and the plurality of light sources 4. Therefore, light from the plurality of light sources 4 arranged in the first direction (X-axis direction) is incident on the incident surface 10 of the optical system 100. In this embodiment, as an example, the illumination system 200 includes 7 light sources 4, and light from these 7 light sources 4 is incident on the incident surface 10.

[0099] Since the multiple light control bodies 2 adopt a common structure, the structure described below for one light control body 2 is the same as that for the other light control bodies 2 unless otherwise stated. Similarly, since the multiple light sources 4 adopt a common structure, the structure described below for one light source 4 is the same as that for the other light sources 4 unless otherwise stated. Furthermore, since the multiple prism sheets 3 also adopt a substantially common structure, the structure described below for one prism sheet 3 is the same as that for the other prism sheets 3 unless otherwise stated.

[0100] The light source 4 is, for example, a solid-state light-emitting element such as a light-emitting diode (LED) or an organic electroluminescence (OEL) element. In this embodiment, as an example, the light source 4 is a sheet-shaped LED element. While such a light source 4 actually emits light over a certain area of ​​its surface (light-emitting surface), it can ideally be considered a point light source emitting light from a single point on its surface. Therefore, the following description assumes that the light source 4 is an ideal point light source.

[0101] In this embodiment, such as Figure 1A As shown, the light source 4 is configured to face the incident surface 10 of the light guide member 1 with a given gap. Furthermore, the light control unit 2 is located between the light source 4 and the incident surface 10 of the light guide member 1.

[0102] In this embodiment, the light control unit 2 and the light guide member 1 are integrated. The term "integrated" in this disclosure refers to a form in which multiple elements (parts) are physically treated as a single unit. That is, multiple elements being integrated means that multiple elements can be assembled into one and treated as a single component. In this case, the multiple elements can be inseparable, like a single molded article, or they can be multiple separately manufactured elements mechanically joined, for example, by welding, bonding, or riveting. In short, the light guide member 1 and the light control unit 2 only need to be integrated in an appropriate manner.

[0103] More specifically, in this embodiment, as described above, the light guide member 1 and the light control body 2 are integrated as a single molded product. That is, in this embodiment, the light guide member 1 and the light control body 2 are integrally molded products and are inseparable. Therefore, as described above, the incident surface 10 in the light guide member 1 is an "imaginary surface" defined inside the integral molded product of the light guide member 1 and the light control body 2, and does not have a solid form.

[0104] Here, as Figure 3A As shown, multiple light sources 4 are arranged with a given interval in the X-axis direction. Each of the multiple light sources 4 corresponds one-to-one with a multiple light control body 2. That is, the multiple light control bodies 2 are also arranged in the X-axis direction in the same way as the multiple light sources 4. Here, the spacing between the multiple light sources 4 in the X-axis direction is equal to the spacing between the multiple light control bodies 2.

[0105] The light guide member 1 is a member that guides light from the light source 4 from the incident surface 10 into the light guide member 1 and through the light guide member 1 to the second surface 12, which serves as the emission surface; that is, it is a member that guides light. In this embodiment, as an example, the light guide member 1 is a molded product of a resin material with light transmittance, such as acrylic resin, and is formed into a plate shape. That is, the light guide member 1 is a light guide plate with a certain thickness.

[0106] As described above, the light guide member 1 has an incident surface 10 for light incidence and two opposing first surfaces 11 and 12 (emission surfaces). Furthermore, the light guide member 1 has an end surface 13 opposite to the incident surface 10 (see reference). Figure 1A ).

[0107] Specifically, in this embodiment, such as Figures 2A to 2D As shown, the light guide member 1 is a rectangular plate, with two opposing surfaces in the thickness direction being surface 11 and surface 12. Furthermore, one of the four end faces (circumferential surfaces) of the light guide member 1 is the incident surface 10. That is, the light guide member 1 is rectangular in shape when viewed from above (from the Z-axis direction). Here, as an example, the light guide member 1 is formed as a rectangle with a dimension in the Y-axis direction smaller than that in the X-axis direction. Moreover, the two surfaces in the thickness direction (Z-axis direction) of the light guide member 1 constitute surface 11 and surface 12, respectively. Furthermore, the two surfaces in the short side direction (Y-axis direction) of the light guide member 1 constitute the incident surface 10 and the end face 13, respectively.

[0108] Furthermore, in this embodiment, the end face 13 is divided into an inclined surface 131 and a vertical surface 132 in the Z-axis direction. The inclined surface 131 is a plane inclined relative to the incident surface 10 such that the distance from the incident surface 10 in the Y-axis direction is greater on the second surface 12 side than on the first surface 11 side. On the other hand, the vertical surface 132 is a plane parallel to the incident surface 10. Here, the inclined surface 131 is adjacent to the second surface 12, and the vertical surface 132 is adjacent to the first surface 11.

[0109] Thus, one of the two end faces of the light guide component 1 that are opposite each other in the Y-axis direction ( Figure 1A The left-hand side of the light guide member 1 is the incident surface 10 where light emitted from multiple light sources 4 passes through multiple light control bodies 2 and enters the light. The two opposing surfaces of the light guide member 1 along the Z-axis are surface 11 and surface 12. Surface 11 is... Figure 1A The lower surface of the middle, the second surface 12 is Figure 1A The upper surface of the light guide member 1. Moreover, the second surface 12 is the emitting surface from the inside of the light guide member 1 to the outside. Therefore, the light guide member 1 emits light from the second surface 12, which is the emitting surface, by having light enter from one end face of the incident surface 10.

[0110] Furthermore, in this embodiment, the second surface 12 is a plane parallel to the XY plane. Similarly, the incident surface 10 is a plane parallel to the XZ plane. The "XY plane" referred to here is a plane including the X-axis and Y-axis, and is orthogonal to the Z-axis. Likewise, the "XZ plane" referred to here is a plane including the X-axis and Z-axis, and is orthogonal to the Y-axis. In other words, the second surface 12 is a plane orthogonal to the Z-axis, and the incident surface 10 is a plane orthogonal to the Y-axis. Therefore, the second surface 12 and the incident surface 10 are orthogonal to each other.

[0111] On the other hand, the first surface 11 is a plane that is not parallel to the XY plane but is inclined relative to it. That is, the first surface 11 and the incident surface 10 are not orthogonal to each other. Specifically, the first surface 11 is inclined relative to the XY plane in such a way that it moves closer to the second surface 12 as it moves away from the incident surface 10. That is, in this embodiment, the first surface 11 and the second surface 12 are inclined relative to each other.

[0112] Furthermore, in this embodiment, a light distribution control unit 14 is provided on the second surface 12. The light distribution control unit 14 controls the light distribution of light drawn from the second surface 12, which serves as the emission surface. The light distribution control unit 14 includes a lens. In this embodiment, as an example, the light distribution control unit 14 includes a multi-lens, also known as a cylindrical lens, which includes a group of multiple semi-cylindrical small lenses arranged in the X-axis direction. In this embodiment, the light distribution control unit 14 is integrally formed with the light guide member 1. That is, in this embodiment, the light guide member 1 and the light distribution control unit 14 are integrally formed and are inseparable.

[0113] A light control unit 2 is disposed between the light source 4 and the incident surface 10 of the light guide member 1. The light control unit 2 controls the light output from the light source 4 and incident on the incident surface 10. In this embodiment, the light control unit 2 has a collimation function that brings the light output from the light source 4 closer to parallel light. That is, the light control unit 2 is a collimating lens that, if radially diffused light is incident from the light source 4, focuses the light toward the incident surface 10 to bring it closer to parallel light. Here, the light emitted from the light source 4 passes through the light control unit 2 and enters the incident surface 10 of the light guide member 1. Therefore, the light from the light source 4 is controlled by the collimating light control unit 2 to narrow the diffusion angle and exit toward the incident surface 10 of the light guide member 1. In this embodiment, it is assumed that the light from the light source 4, which is an ideal point light source, is controlled by the light control unit 2 to be ideally parallel light.

[0114] In this embodiment, such as Figure 1AAs shown, the optical axis Ax1 of the light incident from the incident surface 10 of the light guide member 1 is inclined relative to the first surface 11 in such a way that the distance to the first surface 11 decreases as it moves further away from the incident surface 10. Therefore, the parallel light emitted from the incident surface 10 of the light control body 2 into the light guide member 1 becomes parallel light inclined relative to the first surface 11 in such a way that the distance to the first surface 11 decreases as it moves further away from the incident surface 10. Furthermore, the dashed arrows in the accompanying drawings conceptually represent light rays (or light paths) and do not have a physical form.

[0115] In this embodiment, such as Figure 3A As shown, multiple light control elements 2 are arranged along the X-axis at the end of the incident surface 10 constituting the light guide member 1. That is, in this embodiment, the light control elements 2 and the light guide member 1 are integrated. Furthermore, as already described, each of the multiple light control elements 2 corresponds to one of the multiple light sources 4. Therefore, each of the multiple light control elements 2 controls the diffusion angle of the light emitted by its corresponding light source 4 and emits light towards the incident surface 10.

[0116] Multiple prism sheets 3 are disposed on the first surface 11, reflecting light passing through the interior of the light guide member 1 toward the second surface 12. Each of the multiple prism sheets 3 is configured to perform total internal reflection of the incident light. Of course, each prism sheet 3 is not limited to performing total internal reflection of all the incident light; it may also include a portion of the light that is not totally reflected and passes through the interior of the prism sheet 3.

[0117] In the light guide member 1, most of the light incident from the incident surface 10 is not reflected by any part of the first surface 11 or the second surface 12 other than the plurality of prism sheets 3, but is reflected by any one of the plurality of prism sheets 3 and exits from the second surface 12. That is, the light guide member 1 includes a direct light path L1 in which light incident from the incident surface 10 is directly reflected by any one of the plurality of prism sheets 3 and exits from the second surface 12.

[0118] In this embodiment, each of the plurality of prism sheets 3 has a given length and is formed on the first surface 11 such that its cross-section, when viewed from one side along its long side, is a triangular concave portion. In other words, each of the plurality of prism sheets 3 is formed as a triangular prism. The prism sheet 3 is formed, for example, by machining the first surface 11 of the light guide member 1. Figure 1B As shown, the prism sheet 3 has a reflective surface 30, which reflects light that has passed through the interior of the light guide member 1 toward the second surface 12. Figure 1B It is Figure 1A The diagram shows a magnified schematic end face view of region A1.

[0119] The angle θ1 formed by the reflecting surface 30 and the first surface 11 (i.e., the tilt angle of the reflecting surface 30) is such that the incident angle θ0 of the light incident on the reflecting surface 30 becomes a critical angle or higher. That is, the reflecting surface 30 is tilted relative to the first surface 11, causing total internal reflection of the incident light. In this embodiment, as... Figure 6A As shown, when viewed from one side along the Z-axis, the multiple prism sheets 3 are generally arranged in a zigzag pattern on the first face 11. Here, Figure 6A It is Figure 2C A schematic top view enlarged in area A1. Furthermore, Figure 6B , Figure 6C as well as Figure 6D They are respectively to Figure 6A Enlarged schematic top views of areas A1, A2, and A3.

[0120] Furthermore, in the optical system 100 according to this embodiment, as described above, the tilt angle θ10 of two or more of the plurality of prism sheets 3 relative to the incident surface 10 varies at least according to their positions in the first direction (X-axis direction). Moreover, the tilt angle θ10 of two or more of the plurality of prism sheets 3 is determined such that the closer the prism sheet is to either end in the first direction of the first surface 11, i.e., the further out in the X-axis direction, the more the light emitted from the second surface 12 is oriented towards the outer side of the first direction relative to the reference ray L100. Essentially, as... Figures 6A to 6D As shown, the closer the multiple prism sheets 3 are to the two ends in the first direction of the first face 11, that is, the further out in the X-axis direction, the larger the tilt angle θ10 of the prism sheets 3 becomes.

[0121] The shape and configuration of the multiple prism sheets 3 are described in detail in the "(2.4) Prism Sheets" section.

[0122] The following uses Figure 1A , Figure 1B as well as Figure 3A The light emission principle of the optical system 100 in this embodiment will be explained.

[0123] First, such as Figure 1A As shown, light emitted from the light source 4 is directed through the corresponding light control body 2, thereby controlling the diffusion angle. Furthermore, the light with its diffusion angle controlled is emitted from the light control body 2 towards the incident surface 10 of the light guide member 1. In this embodiment, the light emitted from the light control body 2 becomes parallel light parallel to the second surface 12 and is incident perpendicularly to the incident surface 10.

[0124] Furthermore, as described above, the optical axis Ax1 of the light incident from the incident surface 10 of the light guide member 1 is inclined relative to the first surface 11 in such a way that the distance to the first surface 11 becomes smaller the further away from the incident surface 10. Therefore, most of the light incident on the incident surface 10 does not reach the second surface 12 and the end face 13 of the light guide member 1 opposite to the incident surface 10, but reaches the first surface 11.

[0125] Moreover, such as Figure 1B As shown, most of the light incident on the incident surface 10 is not reflected by the first surface 11 and the second surface 12, but is totally reflected by the reflecting surface 30 of any one of the plurality of prism sheets 3 disposed on the first surface 11. That is, the light guide member 1 includes a direct light path L1 in which the light incident from the incident surface 10 is directly reflected by the prism sheet 3 and emitted from the second surface 12. Furthermore, in this embodiment, the direct light path L1 includes the light path of the light totally reflected by the prism sheet 3. The light totally reflected by the reflecting surface 30 of the prism sheet 3 is emitted from the second surface 12.

[0126] In this embodiment, since multiple prism sheets 3 are arranged throughout the entire area of ​​the first surface 11, light passing through the direct optical path L1, as described above, is emitted from the entire area of ​​the second surface 12 of the light guide member 1. Thus, the second surface 12 emits light as a whole.

[0127] Furthermore, in this embodiment, the tilt angle θ10 of two or more of the plurality of prism sheets 3 is determined such that the closer they are to the two ends in the first direction of the first surface 11, the more the light emitted from the second surface 12 is directed outward relative to the reference ray L100 in the first direction. Therefore, as... Figure 3A As shown, the light L10 reflected by the prism sheet 3 and emitted from the second surface 12, which serves as the emitting surface, is emitted in different directions at the center and both ends of the second surface 12 in the first direction (X-axis direction). In particular, since the light L10 is emitted from both ends of the second surface 12 in the first direction outward in the first direction (X-axis direction), the light L10 emitted from the second surface 12 is emitted in a direction that diffuses as a whole.

[0128] Here, the ray that serves as a reference among the rays emitted from the second surface 12 (ray L10) is defined as "reference ray L100". In this embodiment, as an example, such as Figure 3AAs shown, the light ray (light L10) emitted from near the center (central portion) in the first direction (X-axis direction), or more precisely, the light ray (light L10) emitted from the center of the second surface 12, is designated as the reference ray L100. In this embodiment, the reference ray L100 is a ray perpendicular to the second surface 12; in other words, it is a ray along the normal to the second surface 12. That is, the light L10 is emitted from both ends of the second surface 12 in the first direction relative to the reference ray L100 (the normal to the second surface 12) towards the outside in the first direction.

[0129] The advantages of the optical system 100 of this embodiment will be explained below, including a comparison with a general light guide member (light guide plate).

[0130] In a typical light guide component, light incident from the incident surface undergoes multiple reflections along its thickness at both surfaces (corresponding to surface 11 and surface 12) while being guided within the component. Furthermore, by utilizing a prism positioned on one surface (surface 11) along the thickness direction of the light guide component to break the condition for total internal reflection (i.e., the angle of incidence ≥ the critical angle), light exits from the other surface (surface 12) along the thickness direction, which serves as the exit surface. Thus, in a typical light guide component, the exit surface as a whole also emits light.

[0131] However, in a typical light guide as described above, light incident from the incident surface of the light guide is repeatedly reflected multiple times by both surfaces along the thickness direction of the light guide, thus being guided to a portion of the light guide away from the incident surface. Therefore, the more times total internal reflection occurs, the easier it is to break the condition for total internal reflection (i.e., the angle of incidence ≥ the critical angle), and the higher the probability that light will leak out from one surface (corresponding to the first surface 11) along the thickness direction of the light guide.

[0132] On the other hand, in the optical system 100 according to this embodiment, as described above, it includes a light control unit 2 and a plurality of prism sheets 3, so most of the light incident on the incident surface 10 of the light guide member 1 travels along the direct light path L1. That is, in this embodiment, most of the light incident on the incident surface 10 of the light guide member 1 does not undergo repeated total internal reflection at the first surface 11 and the second surface 12, but directly enters the prism sheet 3 and exits from the second surface 12. Therefore, in this embodiment, the conditions for total internal reflection are not destroyed as in a typical light guide member, and light is less likely to leak from the first surface 11. As a result, the light extraction efficiency can be improved, and a relatively large light intensity can be achieved.

[0133] In this embodiment, more than 50% of the light emitted from the second surface 12 via the direct optical path L1 is emitted from the incident surface 10 onto the light guide member 1. That is, although sometimes a portion of the light incident on the incident surface 10 of the light guide member 1 does not pass through the direct optical path L1, in this embodiment, a large portion (more than half) of the light incident on the incident surface 10 is emitted from the second surface 12 via the direct optical path L1. As a result, the light extraction efficiency in the light guide member 1 is at least 50%. More preferably, the light extraction efficiency in the light guide member 1 is 70% or more, and even more than 80%.

[0134] Thus, due to the improved light extraction efficiency in the light guide member 1, optical components such as reflective sheets, prism sheets, dual brightness enhancement films (DBEF), and Fresnel lenses are not required on the first surface 11 side of the light guide member 1. That is, since light is less likely to leak from the first surface 11, sufficient light extraction efficiency can be achieved even without arranging these optical components on the first surface 11 side of the light guide member 1.

[0135] Furthermore, in the optical system 100 according to this embodiment, such as Figure 3A As shown, through the arrangement of multiple prism sheets 3, the light L10 emitted from the second surface 12 is emitted in different directions at its central portion and both ends in the first direction (X-axis direction) of the second surface 12. Therefore, relative to... Figure 3B The optical system 100X involved in the comparative example shown has advantages in the following aspects.

[0136] Figure 3B This is a perspective view showing the outline of the optical system 100X according to the comparative example. In the optical system 100X according to the comparative example, the arrangement of the plurality of prism sheets 3 in the light guide member 1X is different from that in the optical system 100 according to this embodiment. That is, in the optical system 100X according to the comparative example, the plurality of prism sheets 3 arranged in a generally staggered manner on the first surface 11 of the light guide member 1X all have an inclination angle θ10 of 0 degrees relative to the incident surface 10. That is, in the optical system 100X, the plurality of prism sheets 3 are all arranged parallel to the incident surface 10 (parallel to the X-axis).

[0137] In the optical system 100X of the comparative example, the light L10 emitted from the second surface 12, which serves as the emission surface, is also emitted along the normal to the second surface 12. That is, if the second surface 12 is viewed from the front (on the side in the X-axis direction), the light L10 is emitted from the entire area of ​​the second surface 12 in the same direction, and the brightness of the entire area of ​​the second surface 12 becomes approximately uniform. If it is a backlight of a general liquid crystal display, it is not a problem to have the same brightness distribution as the optical system 100X of the comparative example, but in the head-up display mounted on the mobile body B1, such a brightness distribution is not preferred.

[0138] That is, as in the display system 300 of this embodiment, when an optical system 100 including a light guide member 1 is used in a head-up display mounted on a mobile body B1, a specific brightness distribution is sometimes required on the emission surface (second surface 12) of the light guide member 1. Specifically, in a display system 300 such as a head-up display, the image on the display surface 312 is not directly transformed into a virtual image E1, but rather a virtual image E1 is formed via the optical system 320. Therefore, in order to achieve uniform brightness in the virtual image E1, it is necessary to design the brightness distribution on the display surface 312 to achieve uniform brightness while incorporating the characteristics of the optical system 320. Thus, sometimes a desired brightness distribution is required on the emission surface (second surface 12) of the light guide member 1, so that the brightness distribution on the display surface 312 becomes the desired brightness distribution.

[0139] In the optical system 100 according to this embodiment, by studying the arrangement of the multiple prism sheets 3, as follows... Figure 3A As shown, the light L10 emitted from the second surface 12 is emitted in different directions at its central portion and both ends in the first direction (X-axis direction) of the second surface 12. In particular, the light L10 is emitted outward in the first direction (X-axis direction) from both ends of the second surface 12 relative to the reference ray L100, so the light L10 emitted from the second surface 12 is emitted in a direction that diffuses as a whole. As a result, it has the advantage that the brightness distribution in the second surface 12, which is the emission surface, can be adjusted by the tilt angle θ10 of the multiple prism sheets 3, and the desired brightness distribution can be easily achieved.

[0140] (2.4) Prism Sheet

[0141] Next, refer to Figures 6A to 7C The shape and configuration of the multiple prism sheets 3 will be described in detail.

[0142] exist Figure 6A as well as Figure 7A Only a portion of the first facet 11 is shown; in reality, multiple prism sheets 3 are formed over approximately the entire area of ​​the first facet 11. Furthermore, in... Figure 6A as well as Figure 7A In order to illustrate the shape and arrangement of the multiple prism sheets 3, the multiple prism sheets 3 are spaced out compared to the actual number, and the multiple prism sheets 3 are schematically represented by showing each prism sheet 3 as larger than the actual object. Figure 8 The accompanying diagrams also schematically depict multiple prism sheets 3.

[0143] In the optical system 100 of this embodiment, as described above, when viewed from one side in the Z-axis direction, the plurality of prism sheets 3 are generally arranged in a zigzag pattern on the first surface 11. Here, each of the plurality of prism sheets 3 is formed into a rectangular shape with a given length when viewed from above (from one side in the Z-axis direction).

[0144] Specifically, the plurality of prism sheets 3 are arranged on the first surface 11 with gaps in the first direction (X-axis direction). Furthermore, the plurality of prism sheets 3 are also arranged on the second surface 12 with gaps in the Y-axis direction, which is a second direction orthogonal to the first direction (X-axis direction). Moreover, when the columns of the plurality of prism sheets 3 arranged along the X-axis direction are designated as the first column, the second column, the third column, etc., counting from the incident surface 10 side along the Y-axis direction, the plurality of prism sheets 3 included in the even-numbered columns and the plurality of prism sheets 3 included in the odd-numbered columns are positioned offset from each other in the X-axis direction.

[0145] In this embodiment, in particular, a plurality of prism sheets 3 are arranged on an imaginary arc Va1 in the first surface 11. The imaginary arc Va1 is an imaginary "arc" defined on the first surface 11 and does not have a solid form. In this embodiment, as an example, the imaginary arc Va1 is an imaginary "arc" formed by a portion of the circumference of a perfect circle. Here, viewed from the imaginary arc Va1, the center of the perfect circle including the imaginary arc Va1 is located on the side opposite to the incident surface 10 in the Y-axis direction. Therefore, the imaginary arc Va1 is curved in such a way that its central portion in the X-axis direction bulges toward the incident surface 10, thus becoming an imaginary arc. The "arc" referred to in this disclosure is not limited to a portion of the circumference of a perfect circle with a fixed curvature, but may also be a portion of the circumference of an ellipse or a long circle whose curvature changes midway.

[0146] In this embodiment, a plurality of imaginary arcs Va1 are provided in the second direction (Y-axis direction). As an example, in this embodiment, these imaginary arcs Va1 are formed as concentric circles at equal intervals. That is, each imaginary arc Va1 is a curved imaginary arc that bulges towards the incident surface 10 from its central portion in the X-axis direction. Furthermore, the radii of curvature of the plurality of imaginary arcs Va1 are different from each other; the closer the imaginary arc Va1 is to the incident surface 10 in the Y-axis direction, the larger its radius of curvature becomes. In other words, when the plurality of imaginary arcs Va1 are designated as the 1st, 2nd, 3rd, etc., counting from the incident surface 10, the radii of curvature of the imaginary arcs Va1 decrease in the order of the 1st, 2nd, 3rd, etc.

[0147] Furthermore, the multiple prism sheets 3 are distributed on these multiple imaginary arcs Va1 in such a way that two or more prism sheets 3 are provided on each imaginary arc Va1. That is, two or more prism sheets 3 in each of the first, second, third, ... columns counted from the incident surface 10 in the Y-axis direction are respectively arranged on the imaginary arcs Va1 in the first, second, third, ... columns counted from the incident surface 10. Furthermore, since the multiple prism sheets 3 included in the even-numbered columns and the multiple prism sheets 3 included in the odd-numbered columns are staggered relative to each other in the X-axis direction, thus... Figure 6A As shown, the prism sheet 3 on the adjacent imaginary arc Va1 is positioned offset from each other in the X-axis direction.

[0148] Furthermore, in this disclosure, when referring to the arrangement and spacing of the prism sheets 3 within the first facet 11, it refers to the representative point P1 (see reference) included within each prism sheet 3 in a top view (viewed from one side along the Z-axis). Figure 7A The position and spacing of the prism sheets 3. That is, since each prism sheet 3 has a certain size (area) when viewed from above, the precise position of each prism sheet 3 is defined by a representative point P1 for each prism sheet 3. The representative point P1 is an imaginary "point" set within each prism sheet 3 when viewed from above, and does not have a physical form. In this embodiment, as an example, it is assumed that the representative point P1 is the center (centroid) of the prism sheet 3 when viewed from above. That is, in this embodiment, as... Figure 7A As shown, multiple prism sheets 3 are arranged on the first face 11 such that, when viewed from above (from one side in the Z-axis direction), each representative point P1 is located on the imaginary circular arc Va1.

[0149] Furthermore, the tilt angle θ10 of two or more of the multiple prism sheets 3 is determined such that the closer they are to the two ends in the first direction of the first facet 11, i.e., the further out in the X-axis direction, the more the light emitted from the second facet 12 is tilted outward in the first direction relative to the reference ray L100. In other words, by passing through two or more of the multiple prism sheets 3, and thus being closer to the two ends in the first direction of the first facet 11, the light emitted from the second facet 12 is tilted significantly outward in the first direction relative to the reference ray L100. Essentially, as... Figures 6A to 6D As shown, the closer the multiple prism sheets 3 are to the two ends in the first direction of the first face 11, that is, the further out in the X-axis direction, the larger the tilt angle θ10 of the prism sheets 3 becomes. In this embodiment, as... Figures 6B to 6D As shown, the tilt angle θ10 is the angle relative to the incident plane 10 of the central axis passing through the representative point P1 and parallel to the length of the prism sheet 3 when viewed from above (from one side along the Z-axis), i.e., the angle relative to the X-axis. That is, the tilt angle θ10 represents the degree of tilt of the prism sheet 3 with a given length relative to the incident plane 10. In a prism sheet 3 parallel to the incident plane 10, the tilt angle θ10 is "0 degrees".

[0150] More specifically, in this embodiment, the tilt angle θ10 of each prism sheet 3 is set such that the central axis of each prism sheet 3 coincides with the tangent of the imaginary arc Va1 at the representative point P1 of each prism sheet 3. Therefore, if we consider two prism sheets 3 on the same imaginary arc Va1, the prism sheet 3 adjacent to one prism sheet 3 in the clockwise direction becomes a shape in which one prism sheet 3 is rotated clockwise around the representative point P1. That is, even on the same imaginary arc Va1, the further away from the center in the first direction (X-axis direction), the larger the tilt angle θ10 becomes. Furthermore, if we consider two prism sheets 3 located in the same column counting from the center in the first direction, the prism sheet 3 on the imaginary arc Va1 with a smaller radius of curvature relative to one prism sheet 3 has a larger tilt angle θ10 compared to one prism sheet 3.

[0151] Therefore, in the prism sheet 3 located at the center in the first direction (X-axis direction) of the first face 11, as... Figure 6B ( Figure 6A As shown in region A1), the tilt angle θ10 becomes the first angle θ101 formed by "0 degrees". Furthermore, as... Figure 6C ( Figure 6A As shown in region A2), in prism sheet 3, which is in the third column counting from the center with the center of the first direction as the first column, the tilt angle θ10 becomes a second angle θ102, which is greater than the first angle (0 degrees). Furthermore, as Figure 6D ( Figure 6AAs shown in region A3), in the prism sheet 3 located in the third column from the center of the first direction and in the third column from the side of the incident surface 10 in the second direction, the tilt angle θ10 becomes the third angle θ103, which is greater than the second angle θ102. That is, the first angle θ101, the second angle θ102, and the third angle θ103 are in the relationship of "θ101 < θ102 < θ103".

[0152] Through the configuration of multiple prism sheets 3 as described above, such as Figure 6A As shown, the closer the parallel light L10 incident on the incident surface 10 is to either end in the first direction (X-axis direction), the more it is reflected outwards in the first direction by the prism 3. That is, the reflection direction of the light L10 in the prism 3 is determined by the tilt angle θ10 relative to the incident surface 10 of the prism 3. Therefore, the closer the light L10 is to either end in the first direction on the first surface 11, the larger the tilt angle θ10 of the prism 3 becomes. Consequently, the closer it is to the outer edge of the first direction, the more the light L10 reflected by the prism 3 is directed outwards in the first direction relative to the reference ray L100, and exits from the second surface 12, which serves as the exit surface. Figure 6A In the diagram, the light L10 before reflection in prism sheet 3 is indicated by a hollow arrow, and the light L10 after reflection (reflected light) in prism sheet 3 is indicated by an arrow marked with a shaded area (dotted shading line).

[0153] Furthermore, in this embodiment, such as Figure 7A As shown, when viewed from above (from one side along the Z-axis), the spacing of the plurality of prism sheets 3 is uniform in the first direction (X-axis direction). Here, "spacing in the first direction" refers to the distance (interval) between representative points P1 in the first direction (X-axis direction). That is, the spacing between the representative points P1 of the plurality of prism sheets 3 in the first direction is set to be constant. In this embodiment, the plurality of prism sheets 3 including those in even-numbered columns and those including those in odd-numbered columns, counting from the incident surface 10 in the Y-axis direction, are positioned offset from each other in the X-axis direction. When this offset in the X-axis direction is set to a unit spacing Dx1, the spacing in the first direction for a pair of adjacent prism sheets 3 on the same imaginary arc Va1 becomes twice the unit spacing Dx1 (2Dx1).

[0154] Thus, the plurality of prism sheets 3 includes a first group and a second group. The first group includes two adjacent prism sheets 3 in the first direction. The second group is located at the center of the first direction further away from the first facet 11 than the first group, and includes two adjacent prism sheets 3 in the first direction. The spacing in the first direction is the same in both the first and second groups. For example, the center of the first direction (X-axis direction) in the first facet 11 is defined as the first column, the prism sheets 3 located in the first column and the prism sheets 3 located in the second column are defined as the first group, and the prism sheets 3 located in the second column and the prism sheets 3 located in the third column are defined as the second group. In this case, the spacing (2Dx1) in the first direction is the same for both the first group (prism sheets 3 in the first and second columns) and the second group (prism sheets 3 in the second and third columns). That is, in this embodiment, a pair of prism sheets 3 having at least two groups with the same spacing (2Dx1) in the first direction (X-axis direction) is formed.

[0155] Furthermore, the spacing in the first direction between two adjacent prism sheets 3 in the first direction is the same across all the prism sheets 3. That is, in this embodiment, the spacing (2Dx1) in the first direction (X-axis direction) is the same for all the prism sheets 3. Thus, when viewed from above (from one side in the Z-axis direction), it is possible to achieve a plurality of prism sheets 3 with uniform spacing in the first direction (X-axis direction).

[0156] Furthermore, the plurality of prism sheets 3 include a third group and a fourth group. The third group includes two adjacent prism sheets 3 on the imaginary arc Va1. The fourth group is located at the center of the first direction, farther away from the first face 11 than the third group, and includes two adjacent prism sheets 3 on the imaginary arc Va1. Of the third and fourth groups, the fourth group has a wider spacing along the imaginary arc Va1. The "spacing along the imaginary arc Va1" referred to here means the distance (interval) between representative points P1 on the imaginary arc Va1. For example, the first column is defined as the center of the first direction (X-axis direction) in the first face 11, the second group is defined as the two prism sheets 3 located on both sides of the first column (the second column), and the fourth group is defined as the prism sheets 3 located in the second column and the prism sheets 3 located in the fourth column. In this case, the spacing Dc2 along the imaginary arc Va1 in the fourth group (the prism sheets 3 in the second and fourth columns) is larger than the spacing Dc1 along the imaginary arc Va1 in the third group (the prism sheets 3 in the second column). That is, in Figure 7A In the equation, the spacing Dc1 and spacing Dc2 are related as “Dc1 < Dc2”.

[0157] However, in this embodiment, since the multiple prism sheets 3 are arranged on the imaginary arc Va1 in the first surface 11, the spacing in the second direction (Y-axis direction) is not uniform when viewed from above (from the side of the Z-axis direction). Here, "spacing in the second direction" refers to the distance (interval) between representative points P1 in the second direction (Y-axis direction). That is, as... Figure 7A As shown, the distance between adjacent pairs of prism sheets 3 in the Y-axis direction in the second direction becomes larger the closer they are to the two ends in the first direction (X-axis direction) of the first face 11. For example, taking the center of the first direction (X-axis direction) in the first face 11 as the first column, the distance Dy2 between two prism sheets 3 located in the fourth column from the center is greater than the distance Dy1 between two prism sheets 3 located in the first column. That is, in Figure 7A In the equation, the spacing Dy1 and spacing Dy2 are related as “Dy1 < Dy2”.

[0158] Furthermore, in this embodiment, the shapes of the multiple prism sheets 3 are not exactly the same; the multiple prism sheets 3 include multiple types of prism sheets 3 with different shapes. Specifically, the tilt angle θ1 of the reflecting surface 30 of the multiple types of prism sheets 3 and the depth of the concave portion of the prism sheet 3 (in other words, the height of the prism sheet 3) are different. In other words, the multiple prism sheets 3 include two or more prism sheets 3 with different heights H11 and H12 from the first surface 11.

[0159] In this embodiment, regarding the heights H11 and H12 of the plurality of prism sheets 3, the closer they are to the two ends in the first direction (X-axis direction) of the first facet 11, the higher the height. In other words, the farther away from the center of the first facet 11 in the X-axis direction, the higher the heights H11 and H12 of the prism sheet 3. Specifically, among the prism sheets 3 located at the center in the first direction (X-axis direction) of the first facet 11, such as... Figure 7B ( Figure 7A As shown in the cross-sectional view along line A1-A1, the tilt angle θ1 of the reflecting surface 30 is the first angle θ11, and it has a height H11. On the other hand, in the prism sheet 3 located in the fourth column from the center with the center of the first direction as the first column, as... Figure 7C ( Figure 7A As shown in the cross-sectional view along line B1-B1, the tilt angle θ1 of the reflecting surface 30 is a second angle θ12, which is greater than the first angle θ11, and has a height H12. Here, the heights H11 and H12 are in the relationship of "H11 < H12".

[0160] As described above, in this embodiment, the closer the prism sheet 3 is to the two ends in the first direction (X-axis direction) of the first facet 11, the larger the distance between adjacent pairs of prism sheets 3 in the Y-axis direction in the second direction. Therefore, if the height of the multiple prism sheets 3 is uniform, the closer the prism sheet 3 is to the two ends in the first direction (X-axis direction) of the first facet 11, the more light is not captured by the prism sheet 3, which may result in light loss. In this embodiment, considering this, the height of the prism sheet 3 is increased by placing it closer to the two ends in the first direction (X-axis direction) of the first facet 11, thereby reducing the light that is not captured by the prism sheet 3 and thus reducing light loss.

[0161] As an example, the height of the prism sheet 3 is preferably 1 μm or more and 100 μm or less. Similarly, as an example, the spacing between the plurality of prism sheets 3 in the Y-axis direction is preferably 1 μm or more and 1000 μm or less.

[0162] Here, among the various types of prism sheets 3, only the tilt angle θ1 of the reflecting surface 30 and the height of the prism sheet 3 differ; other shapes are the same. Therefore, the shape of the prism sheet 3, including its length along its long side, as viewed from above (from one side along the Z-axis), is the same in all the prism sheets of the plurality of prism sheets 3. Thus, in this embodiment, the length W1 of each of the plurality of prism sheets 3 is the same in all the prism sheets of the plurality of prism sheets 3. For example, in Figure 7A In the first column, the center of the first direction (X-axis direction) in the first face 11 is taken as the first column. The length W1 of the prism sheet 3 located in the third column from the center is the same as the length of the prism sheet 3 located in the first column (same as the effective length Lx1).

[0163] Therefore, the closer a position is to either end of the first direction of the first facet 11, the smaller the effective length of the prism sheet 3 in the first direction (X-axis direction). The "effective length of the prism sheet 3 in the first direction" referred to here is the length of the edge of the prism sheet 3 projected onto the incident surface 10 side in the width direction along the X-axis. That is, in this embodiment, the closer a position is to either end of the first direction (X-axis direction) of the first facet 11, the larger the tilt angle θ10 relative to the incident surface 10 becomes, and thus the smaller the effective length becomes. For example, taking the center of the first direction (X-axis direction) in the first facet 11 as the first column, the effective length Lx2 of the prism sheet 3 located in the fourth column from the center is smaller (shorter) than the effective length Lx1 of the prism sheet 3 located in the first column. That is, in Figure 7A In this context, the effective length Lx1 and the effective length Lx2 are related as “Lx2 < Lx1”.

[0164] (3) Variations

[0165] Embodiment 1 is merely one of the various embodiments of this disclosure. Various modifications can be made to Embodiment 1, depending on the design, etc., as long as the objectives of this disclosure are achieved. The figures described in Embodiment 1 are schematic, and the ratios of the size and thickness of the constituent elements in the figures are not necessarily intended to reflect actual dimensions.

[0166] Hereinafter, variations of Embodiment 1 will be listed. The variations described below can be appropriately combined with Embodiment 1.

[0167] (3.1) First variation

[0168] like Figure 8 As shown, the optical system 100A in the first modification differs from the optical system 100 in Embodiment 1 in that the length of each of the plurality of prism sheets 3A is not the same in all of the prism sheets of the plurality of prism sheets 3A.

[0169] That is, in the first variation, such as Figure 8 As shown, regarding the length of each of the multiple prism sheets 3A, the closer they are to the ends in the first direction (X-axis direction) of the first facet 11, the longer the length. For example, in Figure 8 In the first column, with the center of the first direction (X-axis direction) in the first face 11 as the first column, the length W2 of the prism sheet 3A located in the third column from the center is greater than the length W1 of the prism sheet 3A located in the first column. That is, in Figure 8 The lengths W1 and W2 are related as “W1 < W2”.

[0170] exist Figure 8 In the example, the first facet 11 is divided into a first region Z1, a second region Z2, and a third region Z3 along the X-axis, and the length of the prism sheet 3A is determined for each region. The second region Z2 is located at the center of the first direction (X-axis direction) in the first facet 11, and the first region Z1 and the third region Z3 are located on either side of the second region Z2 along the first direction. That is, the prism sheet 3A in the second region Z2, which is located at the center of the first direction, has a length W1, and the prism sheets 3A in the first region Z1 and the third region Z3 have a length W2.

[0171] According to the optical system 100A of the first modification, the difference in effective length in the first direction (X-axis direction) of the prism sheet 3A can be minimized. That is, with respect to this modification, the closer the position is to the two ends in the first direction (X-axis direction) of the first surface 11, the larger the tilt angle θ10 relative to the incident surface 10 becomes, but the length of the prism sheet 3A becomes larger (longer). For example, taking the center of the first direction (X-axis direction) in the first surface 11 as the first column, the effective length Lx2 of the prism sheet 3A located in the fourth column from the center is shorter than the effective length Lx1 of the prism sheet 3A located in the first column, but the difference is smaller. As a result, according to the first modification, the effective length of the prism sheet 3A is also maintained at both ends in the first direction (X-axis direction) of the first surface 11, thereby reducing the light that cannot be captured by the prism sheet 3A and thus reducing loss.

[0172] (3.2) Second variation

[0173] like Figure 9 As shown, the optical system 100B in the second modification differs from the optical system 100 in Embodiment 1 in that the spacing in the first direction of the plurality of prism sheets 3B is not the same in all of the plurality of prism sheets 3.

[0174] That is, in the second variation, such as Figure 9 As shown, the spacing Dc1 along the imaginary arc Va1 is uniform. Furthermore, the radii of curvature of the multiple imaginary arcs Va1 are different from each other, resulting in non-uniform spacing of the multiple prism sheets 3B in the first direction (X-axis direction). In summary, in the Y-axis direction, the closer the imaginary arc Va1 is to the incident surface 10, the larger its radius of curvature. Therefore, the spacing in the first direction between adjacent pairs of prism sheets 3B on the first imaginary arc Va1, counting from the incident surface 10, is greater than the spacing in the first direction between adjacent pairs of prism sheets 3B on the third imaginary arc Va1.

[0175] The result is, as Figure 9 As shown, a positional deviation of the representative point P1 is also generated in the first direction (X-axis direction) between the plurality of prism sheets 3B arranged along the second direction (Y-axis direction), and a gap Sp1 in the first direction is generated between the plurality of prism sheets 3B arranged along the second direction. Due to this gap Sp1, the closer the position is to the two ends in the first direction (X-axis direction) of the first surface 11, the more light is not captured by the prism sheets 3B, which may cause loss. Therefore, the optical system 100 according to Embodiment 1, in which the spacing of the plurality of prism sheets 3 in the first direction is uniform, is more likely to reduce loss than the second variation.

[0176] (3.3) Other variations

[0177] Alternatively, the first surface 11 can be a surface orthogonal to the incident surface 10, and the second surface 12 can be a surface that is not orthogonal to the incident surface 10 but is inclined relative to the XY plane. In addition, both the first surface 11 and the second surface 12 can be surfaces that are not orthogonal to the incident surface 10 but are inclined relative to the XY plane.

[0178] Furthermore, in Embodiment 1, the light guide member 1 is formed as a rectangle with a dimension in the Y-axis direction smaller than that in the X-axis direction. The two surfaces of the light guide member 1 in the short side direction (Y-axis direction) become the incident surface 10 and the end surface 13, respectively, but this structure is not limited to this. For example, such as... Figure 10 As shown, the two sides of the long side (i.e., the short side direction, Y-axis direction) of the rectangular light guide member 1 can also be replaced, and the two sides of the short side (i.e., the long side direction, X-axis direction) of the rectangular light guide member 1 can be used as the incident surface 10 and the end surface 13, respectively. In this case, as... Figure 10 As shown, the light incident on the light guide member 1 does not enter from the long side of the light guide member 1, but from the short side. In this case, the Y-axis direction is along both the incident surface 10 and the first surface 11, and is therefore equivalent to the "first direction", while the X-axis direction is equivalent to the "second direction". Furthermore, the light guide member 1 is not limited to a rectangular shape when viewed from above, and can also be a square or a polygon other than a quadrilateral.

[0179] Furthermore, the plurality of prism sheets 3 need only include two or more prism sheets 3 whose tilt angle θ10 differs at least according to their position in the first direction. It is not necessary that all prism sheets 3 have a tilt angle θ10 that differs at least according to their position in the first direction. In short, it is sufficient that there are two or more prism sheets 3 whose tilt angle θ10 differs at least according to their position in the first direction. The plurality of prism sheets 3 may also include prism sheets 3 that do not satisfy the requirement of a tilt angle θ10. In this case, it is sufficient that for two or more prism sheets 3 among the plurality of prism sheets 3, the tilt angle θ10 is determined such that the closer the position is to the two ends in the first direction of the first surface 11, the more the light emitted from the second surface 12 is directed outward relative to the reference ray L100 in the first direction.

[0180] Furthermore, for two or more prisms 3 among a plurality of prism sheets 3, the tilt angle θ10 can also be determined such that the closer the prisms are to the two ends in the first direction of the first surface 11, the more the light emitted from the second surface 12 is directed inward in the first direction. In this case, the light is emitted from the two ends in the first direction of the second surface 12 inward in the first direction (X-axis direction), and thus the light emitted from the second surface 12 is emitted in a direction that narrows as a whole. For example, in a display system 300 such as a head-up display, it is necessary to design the brightness distribution on the display surface 312 to make the brightness uniform while incorporating the characteristics of the optical system 320. Therefore, according to the characteristics of the optical system 320, sometimes a special brightness distribution is required in the emitting surface (second surface 12) of the light guide member 1, which is directed in a direction that narrows as a whole. Therefore, when the light emitted from the second surface 12 is directed inward in the first direction, similar to Embodiment 1, it has the advantage that the brightness distribution in the second surface 12, which is the emission surface, can be adjusted by the tilt angle θ10 of the plurality of prism sheets 3, making it easy to achieve the desired brightness distribution. In short, as long as the tilt angle θ10 of two or more of the plurality of prism sheets 3 is determined such that the closer the position is to the two ends in the first direction of the first surface 11, the more the light emitted from the second surface 12 is directed outward or inward relative to the reference ray L100 in the first direction.

[0181] Furthermore, the multiple prism sheets 3 may include, for example, multiple types of prism sheets 3 with different parameters other than the shape of the reflecting surface 30 or the side surface 31, the tilt angle θ1 of the reflecting surface 30, and the depth of the concave portion of the prism sheet 3 (in other words, the height of the prism sheet 3).

[0182] Furthermore, the multiple prism sheets 3 may all have the same shape, including the tilt angle θ1 of the reflecting surface 30, the depth of the concave portion of the prism sheet 3 (in other words, the height of the prism sheet 3), and the dimensions of the long side of the prism sheet 3.

[0183] Furthermore, when referring to the arrangement and spacing of the prism sheets 3 within the first face 11, the representative point P1 is not limited to the center (center of gravity) of the prism sheet 3 as viewed from above. That is, the representative point P1 only needs to be located within the prism sheet 3 as viewed from above, for example, it can be set to one end of the long side of the prism sheet 3. However, the representative point P1 is preferably near the center (center of gravity) of the prism sheet 3 as viewed from above. For example, it is preferable that the representative point P1 is located in a square centered on the center (center of gravity) of the prism sheet 3 as viewed from above and with one side having the width dimension of the prism sheet 3 as its diameter. Or, for example, it is more preferable that the representative point P1 is located in a circle centered on the center (center of gravity) of the prism sheet 3 as viewed from above and with the width dimension of the prism sheet 3 as its diameter.

[0184] Furthermore, the light guide member 1 only needs to include a direct light path L1, and it is not necessary for all light incident from the incident surface 10 to pass through the direct light path L1. That is, the light guide member 1 may also include, for example, an indirect light path: after being reflected more than once by the first surface 11 or the second surface 12, it is reflected by the prism sheet 3 and emitted from the second surface 12.

[0185] In addition, the light guide component 1 may not include the direct optical path L1.

[0186] Furthermore, in Embodiment 1, the plurality of prism sheets 3 are formed by processing the first surface 11 of the light guide member 1, but this method is not limited to. For example, the plurality of prism sheets 3 can also be disposed on the first surface 11 by adhering a prism sheet material on which the plurality of prism sheets 3 are formed.

[0187] Furthermore, the prism sheet 3 is not limited to being concave relative to the first face 11, i.e., recessed from the first face 11, but can also be convex relative to the first face 11, i.e. protruding from the first face 11.

[0188] Furthermore, the light distribution control unit 14 only needs to control the light distribution drawn from the second surface 12, and it only needs to be provided on at least one of the first surface 11 and the second surface 12. That is, in Embodiment 1, the light distribution control unit 14 is provided on the second surface 12, which is the emission surface, but it is not limited to this structure. The light distribution control unit 14 can also be provided on the first surface 11, or it can be provided on both the first surface 11 and the second surface 12. Furthermore, in Embodiment 1, the light distribution control unit 14 and the light guide member 1 are integrated as a single molded product, but it is not limited to this method. For example, the light distribution control unit 14 can also be provided on the second surface 12 by adhering a light distribution sheet on which the light distribution control unit 14 is formed.

[0189] Furthermore, the light distribution control unit 14 may also be a lens array comprising a group of multiple small lenses arranged in a matrix. Each of the multiple small lenses may be either a convex lens or a concave lens. Moreover, the light distribution control unit 14 may also include Fresnel lenses.

[0190] Furthermore, the light distribution control unit 14 is not limited to a lens; for example, it can be a diffuser, prism, or diffraction grating. Moreover, the light distribution control unit 14 is not a necessary structure in the optical system 100, and it can be appropriately omitted.

[0191] Furthermore, the mobile body B1 equipped with the display system 300 is not limited to automobiles (passenger cars), but may also be large vehicles such as trucks or buses, two-wheeled vehicles, trams, electric cars, construction machinery, aircraft or ships, etc.

[0192] Furthermore, the display system 300 is not limited to a structure that displays virtual images, such as a head-up display. For example, the display system 300 may also be a liquid crystal display or a projection device. In addition, the display system 300 may also be a display for an in-vehicle navigation system, an electronic mirror system, or a multi-information display mounted on the mobile body B11.

[0193] Furthermore, the lighting system 200 is not limited to the structure used in the display system 300; for example, it can also be used for industrial applications such as resin curing or plant cultivation, or for lighting applications including guide lights.

[0194] Furthermore, the light control element 2 is not a necessary structure for the optical system 100 and can be omitted. That is, the optical system 100 only needs to have the light guide component 1 and multiple prism sheets 3, and the light control element 2 can be appropriately omitted.

[0195] Furthermore, when viewed from the perspective of the imaginary arc Va1, the center of the perfect circle including the imaginary arc Va1 can also be located on the side of the incident surface 10 in the Y-axis direction. In this case, the imaginary arc Va1 becomes an imaginary arc that curves in such a way that its central portion in the X-axis direction bulges toward the side opposite to the incident surface 10.

[0196] Furthermore, when multiple prism sheets 3 are arranged on imaginary arcs Va1 in the first facet 11, the fact that the central axis of each prism sheet 3 coincides with the tangent of the imaginary arc Va1 at the representative point P1 of each prism sheet 3 is not a necessary structure for the optical system 100. That is, as long as the representative point P1 of each prism sheet 3 in the first facet 11 is on the imaginary arc Va1, the tilt angle θ10 of each prism sheet 3 does not need to be defined by the imaginary arc Va1. Thus, for example, if considering two prism sheets 3 located in the same column counting from the center of the first direction, the tilt angle θ10 can also be the same regardless of which imaginary arc Va1 they are located on. Alternatively, if considering two prism sheets 3 located in the same column counting from the center of the first direction, the other prism sheet 3 on the imaginary arc Va1 with a smaller radius of curvature relative to one prism sheet 3 can also have a smaller tilt angle θ10 compared to one prism sheet 3.

[0197] Furthermore, when viewed from one side along the Z-axis, the multiple prism sheets 3 are not limited to being located on the imaginary circular arc Va1, but can also be configured as free curves. The term "free curve" as used in this disclosure includes, for example, various free curves such as C-shaped, U-shaped, J-shaped, or S-shaped.

[0198] Furthermore, each of the multiple prism sheets 3 is not limited to a rectangular shape when viewed from above; they can also be formed into an arc shape or a free curve shape.

[0199] Furthermore, the tilt angle θ10 of each of the multiple prism sheets 3 is not strictly defined. For example, the tilt angle θ10 of the prism sheet 3 can also be defined as having a deviation of less than 10 degrees in both the clockwise and counterclockwise directions. Preferably, the deviation of the tilt angle θ10 of the prism sheet 3 is suppressed to less than 5 degrees in both the clockwise and counterclockwise directions.

[0200] Therefore, it is also possible to form multiple prism sheets 3 with respect to the tilt angle θ10 determined in the design of the prism sheet 3, for example, by intentionally adjusting the tilt angle θ10 of each prism sheet 3 randomly by ±5 degrees. Even with such adjustments, multiple prism sheets 3 include cases where the tilt angle θ10 is determined such that the closer the position is to the two ends in the first direction of the first face 11, the more the light emitted from the second face 12 is directed towards the outside or inside of the first direction relative to the reference ray L100.

[0201] Furthermore, the reference ray L100 is not limited to the ray emitted from the center of the second surface 12 (ray L10), but can also be the ray emitted from a position away from the center of the second surface 12 (ray L10).

[0202] Furthermore, the reference ray L100 is not limited to a ray perpendicular to the second surface 12, but can also be a ray that is tilted relative to the normal of the second surface 12.

[0203] (Implementation Method 2)

[0204] like Figures 11A to 11D As shown, the optical system 100C according to this embodiment differs from the optical system 100 according to Embodiment 1 in that a plurality of prism sheets 3C are arranged on the grid points of the imaginary grid Vg1 in the first surface 11. Hereinafter, for structures that are the same as those in Embodiment 1, common reference numerals will be used and descriptions will be omitted as appropriate.

[0205] The imaginary grid Vg1 is an imaginary "grid" defined on the first surface 11 and does not have a physical form. In this embodiment, as an example, the imaginary grid Vg1 is an imaginary "grid" with a different spacing in the first direction (X-axis direction) and a different spacing in the second direction (Y-axis direction). The spacing in the first direction of the imaginary grid Vg1 is a unit spacing Dx1. The spacing in the second direction of the imaginary grid Vg1 is half of the spacing Dy1 (Dy1 / 2).

[0206] In this embodiment, such as Figure 11AAs shown, in a top view (viewed from one side along the Z-axis), multiple prism sheets 3C are arranged on the first face 11 such that their respective representative points P1 are located on the grid points of the imaginary grid Vg1. According to this arrangement, in a top view (viewed from one side along the Z-axis), the spacing (Dx1) in the first direction (X-axis direction) and the spacing (Dy1 / 2) in the second direction (Y-axis direction) of the multiple prism sheets 3C are both uniform.

[0207] In this embodiment, such as Figures 11A to 11D As shown, the closer the multiple prism sheets 3C are to the two ends in the first direction of the first face 11, that is, the further out in the X-axis direction, the larger the tilt angle θ10 of the prism sheets 3C becomes. Figure 11B as well as Figure 11D They are respectively to Figure 11A Enlarged schematic top views of areas A1 and A4. Figure 11C It is Figure 11A Enlarged schematic top views of areas A2 and A3.

[0208] More specifically, if we consider two adjacent prism sheets 3C in the first direction (X-axis direction), the other prism sheet 3C located to the right of one prism sheet 3C becomes a shape in which one prism sheet 3C is rotated clockwise around the representative point P1. That is, the further away from the center of the first direction (X-axis direction), the larger the tilt angle θ10 becomes. Furthermore, if we consider two prism sheets 3C located in the same column counting from the center of the first direction, their tilt angles θ10 are equal.

[0209] Therefore, in the prism sheet 3C located at the center of the first direction (X-axis direction) in the first face 11, as... Figure 11B ( Figure 11A As shown in region A1), the tilt angle θ10 becomes the first angle θ101 formed by "0 degrees". Furthermore, in prism sheet 3C, which is the third column from the center of the first direction (with the center as the first column), as... Figure 11C ( Figure 11A As shown in regions A2 and A3), the tilt angle θ10 becomes a second angle θ102, which is greater than the first angle θ101 (0 degrees). Furthermore, in prism sheet 3C located in the fourth column counting from the center of the first direction, as... Figure 11D ( Figure 11A As shown in region A4), the tilt angle θ10 becomes the third angle θ103, which is greater than the second angle θ102. That is, the first angle θ101, the second angle θ102, and the third angle θ103 are in the relationship of "θ101 < θ102 < θ103".

[0210] With the arrangement of multiple prism sheets 3C as described above, the parallel light incident on the incident surface 10 is reflected more outwards in the first direction (X-axis direction) by the prism sheets 3C the closer it is to the two ends of the first direction. That is, the direction of light reflection in the prism sheets 3C is determined by the tilt angle θ10 of the prism sheets 3C relative to the incident surface 10. Therefore, the closer it is to the two ends of the first direction on the first surface 11, the larger the tilt angle θ10 of the prism sheets 3C becomes. Consequently, the closer it is to the outer edge of the first direction, the more the light reflected by the prism sheets 3C is directed outwards in the first direction relative to the reference ray L100, and exits from the second surface 12, which serves as the exit surface.

[0211] like Figure 12 As shown, the optical system 100D in the modified example of Embodiment 2 differs from the optical system 100C in Embodiment 2 in that the lengths of the plurality of prism sheets 3D are not the same in all the prism sheets of the plurality of prism sheets 3D. This optical system 100D corresponds to the optical system 100A in the first modified example of Embodiment 1 (see...). Figure 8 ).

[0212] That is, in the optical system 100D, such as Figure 12 As shown, regarding the length of each of the multiple prism sheets in 3D, the closer to the two ends in the first direction (X-axis direction) of the first facet 11, the longer the length. For example, in Figure 12 In the first face 11, with the center of the first direction (X-axis direction) as the first column, the length W2 of the prism sheet 3D located in the third column from the center is greater than the length W1 of the prism sheet 3D located in the first column. That is, in Figure 12 In this context, lengths W1 and W2 are related as "W1 < W2". Figure 12 In the example, similar to the first variation of embodiment 1, the first surface 11 is divided into a first region Z1, a second region Z2 and a third region Z3 in the X-axis direction, and the length of the prism sheet 3D is determined according to each region.

[0213] According to the optical system 100D of this modification, the difference in effective length in the first direction (X-axis direction) of the prism 3D can be minimized. That is, in this modification, the closer the position is to the two ends in the first direction (X-axis direction) of the first surface 11, the larger the tilt angle θ10 relative to the incident surface 10 becomes, but the length of the prism 3D becomes larger (longer). For example, taking the center of the first direction (X-axis direction) in the first surface 11 as the first column, the effective length Lx2 of the prism 3D located in the fourth column from the center is shorter than the effective length Lx1 of the prism 3D located in the first column, but the difference is smaller. As a result, according to this modification, the effective length of the prism 3D is maintained at both ends in the first direction (X-axis direction) of the first surface 11, thereby reducing light that cannot be captured by the prism 3D and thus reducing loss.

[0214] As another variation of embodiment 2, the tilt angles θ10 of the multiple prism sheets 3C located in the same column starting from the center of the first direction can also be different.

[0215] Furthermore, the configuration of multiple prism sheets 3C can also be combined with the configuration on the grid points of the imaginary grid Vg1 and the configuration on the imaginary arc Va1.

[0216] The various structures (including variations) described in Embodiment 2 can be appropriately combined with the various structures (including variations) described in Embodiment 1.

[0217] (Implementation Method 3)

[0218] like Figure 13 As shown, the optical system 100E according to this embodiment differs from the optical system 100C according to Embodiment 2 in that it also includes a long strip prism 6. Hereinafter, for structures that are the same as those in Embodiment 2, common reference numerals will be used, and descriptions will be omitted as appropriate.

[0219] A strip prism 6 is disposed among a plurality of prism sheets 3E, within the first surface 11 between two adjacent prism sheets 3E along a second direction orthogonal to the first direction. The strip prism 6 has a length that spans two or more adjacent prism sheets 3E in the first direction. That is, the optical system 100E according to this embodiment includes a strip prism 6 in addition to the plurality of prism sheets 3E, the strip prism 6 being disposed between two adjacent prism sheets 3E in the second direction (Y-axis direction) and having a length that spans two or more adjacent prism sheets 3E in the first direction (X-axis direction).

[0220] In this embodiment, the optical system 100E includes multiple elongated prisms 6. Viewed from one side along the Z-axis, the multiple elongated prisms 6 are each formed as a straight line parallel to the X-axis. Figure 13In the example, multiple elongated prisms 6 are arranged with gaps in the Y-axis direction on the first surface 11 of the light guide member 1. That is, in Figure 13 In the example, the long strip prism 6 is arranged in multiples in the second direction (Y-axis direction).

[0221] A long strip prism 6 is disposed on the first surface 11, reflecting light passing through the interior of the light guide member 1 toward the second surface 12. The long strip prism 6 is configured to perform total internal reflection of the incident light. Of course, the long strip prism 6 is not limited to the method of total internal reflection of the incident light; it may also include the method of partial incomplete reflection of light passing through the interior of the long strip prism 6.

[0222] In this embodiment, each of the plurality of elongated prisms 6 has a length spanning more than two prism sheet pieces 3E, and is formed on the first surface 11 such that its cross-section, when viewed from one side along its long side, is a triangular concave portion. In other words, each of the plurality of elongated prisms 6 is formed as a triangular prism. The elongated prisms 6 are formed, for example, by processing the first surface 11 of the light guide member 1. That is, the cross-sectional shape of the elongated prisms 6 is the same as that of the prism sheet pieces 3E.

[0223] When the columns of the multiple prism sheets 3E arranged along the X-axis direction are designated as column 1, column 2, column 3, ... from the side of the incident surface 10 in the Y-axis direction, the elongated prism 6 is respectively arranged between the multiple prism sheets 3E including the even-numbered columns and the multiple prism sheets 3E including the odd-numbered columns.

[0224] According to the above structure, even if light is generated that cannot be captured by the prism sheet 3E, it can be captured by the long strip prism 6, thereby reducing losses.

[0225] like Figure 14A As shown, the difference between the optical system 100F in the modified embodiment 3 and the optical system 100E in embodiment 3 is that the lengths of the elongated prisms 6A are not uniform. That is, in the optical system 100F of this modified embodiment, multiple elongated prisms 6A are provided, and the lengths of the multiple elongated prisms 6A are different. Figure 14A In the example, among the multiple elongated prisms 6A, the elongated prism 6A closest to the incident surface 10 is shorter in length compared to the other elongated prisms 6A. Furthermore, in Figure 14A In the example, multiple (two) elongated prisms 6A are arranged between two adjacent prism sheets 3F along the second direction. Furthermore, in Figure 14A In the example, multiple prism sheets 3F are formed that partially overlap with the elongated prism 6A.

[0226] like Figure 14BAs shown, the optical system 100G in another variation of Embodiment 3 differs from the optical system 100E in Embodiment 3 in that the elongated prism 6B is arc-shaped. Figure 14B In the example, an arc-shaped elongated prism 6B is arranged between two adjacent prism sheets 3G along the second direction. As an example, the elongated prism 6B is an arc-shaped prism that is curved in such a way that its central portion in the X-axis direction bulges toward the incident surface 10.

[0227] like Figure 15A As shown, the optical system 100H in another variation of Embodiment 3 differs from the optical system 100E in Embodiment 3 in that a plurality of prism sheets 3H are arranged on an imaginary arc Va1. That is, in this variation, a plurality of prism sheets 3H and a strip prism 6C arranged on an imaginary arc Va1 as described in Embodiment 1 are combined. Figure 15A In the example, multiple prism sheets 3H and elongated prism 6C partially overlap.

[0228] like Figure 15B As shown, another variation of embodiment 3 involves an optical system 100I and Figure 15A The difference in the optical system 100H is that multiple prism sheets 3I are arranged on an imaginary arc Va1, and the elongated prism 6D is arc-shaped. That is, in this modified example, multiple prism sheets 3I and elongated prism 6D arranged on an imaginary arc Va1 as described in Embodiment 1 are combined.

[0229] Furthermore, as another variation of embodiment 3, when viewed from one side in the Z-axis direction, the elongated prism 6 is not limited to a straight line or an arc shape, but can also be formed as a free curve.

[0230] The various structures (including variations) described in Embodiment 3 can be appropriately combined with the various structures (including variations) described in Embodiment 1 or 2.

[0231] (Implementation Method 4)

[0232] like Figure 16 As shown, the optical system 100J according to this embodiment differs from the optical system 100 according to Embodiment 1 in that the reference ray L100 is inclined relative to the normal of the second surface 12. Hereinafter, common reference numerals will be used for structures that are the same as those in Embodiment 1, and descriptions will be omitted as appropriate.

[0233] That is, in this embodiment, the reference ray L100 is not a ray perpendicular to the second surface 12, but a ray inclined relative to the normal of the second surface 12. In this embodiment, as an example, such as... Figure 16As shown, the ray (light L10) emitted from near the center (central part) in the first direction (X-axis direction), or more precisely, the ray (light L10) emitted from the center of the second surface 12, is designated as the reference ray L100. Figure 16 In the example, the reference ray L100 is a ray that is tilted toward the positive X-axis relative to the normal of the second surface 12. Moreover, light is emitted from both ends of the second surface 12 in the first direction at a distance L10 toward the outside of the first direction relative to the reference ray L100.

[0234] For example, as described in Embodiment 1, when the optical system 100J is applied to a head-up display mounted on the mobile body B1, such a light distribution (brightness distribution) is sometimes required. That is, in the head-up display, for example, in order to prevent external interference light such as sunlight from being emitted from the display surface 312 (see reference 1), a certain light distribution (brightness distribution) is required. Figure 4 ) Reflection and enter user U1 (refer to) Figure 5 The eye of the image will sometimes display surface 312 relative to the virtual image E1 (reference). Figure 5 The optical axis of the light source is tilted. In this case, the reference ray L100 emitted from the center of the second surface 12, which corresponds to the center of the display surface 312, is preferably a ray that is tilted relative to the normal of the second surface 12. In this case, the reference ray L100 is preferably tilted not only in the Y-axis direction but also in both the X-axis and Y-axis directions relative to the normal of the second surface 12.

[0235] like Figure 17A As shown, the optical system 100J of this embodiment, viewed from above (from one side along the Z-axis), similarly includes multiple prism sheets 3J arranged on an arc (imaginary arc Va1) as in Embodiment 1. Figures 17A to 17D As shown, the closer these prism sheets 3J are to the two ends in the first direction of the first face 11, that is, the further out they are in the X-axis direction, the greater the tilt angle θ10 (θ101) of the prism sheet 3J relative to the center in the first direction becomes. Figure 17B , Figure 17C as well as Figure 17D They are respectively to Figure 17A Enlarged schematic top views of areas A1, A2, and A3.

[0236] More specifically, in the prism sheet 3J located at the center of the first direction, the tilt angle θ10 relative to the incident plane 10 is not 0 degrees, but has a certain magnitude. Moreover, if we consider two adjacent prism sheets 3J in the first direction (X-axis direction), the other prism sheet 3J located to the right of one prism sheet 3J becomes a shape that rotates one prism sheet 3J clockwise around the representative point P1. That is, with the prism sheet 3J located at the center of the first direction as a reference, the further away from the center of the first direction (X-axis direction), the greater the difference in tilt angle θ10 from the reference prism sheet 3J.

[0237] Here, the tilt angle θ10 of the prism sheet 3J, which has a tilt angle of 0 degrees, when rotated clockwise around the representative point P1, is defined as a positive angle, and the tilt angle θ10 when rotated counterclockwise around the representative point P1 is defined as a negative angle. That is, the tilt angle θ10 increases when the prism sheet 3J is rotated clockwise, and decreases when the prism sheet 3J is rotated counterclockwise. Thus, in this embodiment, in the prism sheet 3J located at the center in the first direction (X-axis direction) of the first surface 11, as... Figure 17B ( Figure 17A As shown in region A1), the tilt angle θ10 is not 0 degrees, but becomes the first angle θ101, which is a negative angle. Furthermore, in the prism sheet 3J, which is the third column counting from the center with the center of the first direction as the first column, as... Figure 17C ( Figure 17A As shown in region A2), the tilt angle θ10 becomes a second angle θ102, which is greater than the first angle θ101. Furthermore, in the prism sheet 3J located in the fourth column counting from the center of the first direction, as... Figure 17D ( Figure 17A As shown in region A3), the tilt angle θ10 becomes the third angle θ103, which is greater than the second angle θ102. That is, the first angle θ101, the second angle θ102, and the third angle θ103 have the relationship of "θ101 < θ102 < θ103".

[0238] In summary, in this embodiment, the tilt angle θ of the prism sheet 3J is not necessarily smaller closer to the center in the X-axis direction and larger further outward in the X-axis direction. However, always with the prism sheet 3J located at the center in the first direction as the reference, the further away from the center in the first direction (X-axis direction), the greater the difference between the tilt angle θ10 and the reference prism sheet 3J. That is, the further away from the center in the first direction (X-axis direction), the larger the tilt angle θ10 of the prism sheet 3J gradually becomes in one direction (clockwise or counterclockwise).

[0239] With the arrangement of multiple prism sheets 3J as described above, the closer the parallel light incident on the incident surface 10 is to either end in the first direction (X-axis direction), the more it is reflected outwards in the first direction relative to the reference ray L100 by the prism sheets 3J. That is, the direction of light reflection in the prism sheets 3J is determined by the tilt angle θ10 relative to the incident surface 10 of the prism sheets 3J. Therefore, the closer the light is to either end in the first direction of the first surface 11, the larger the tilt angle θ10 of the prism sheets 3J becomes. Consequently, the closer to the outer edge of the first direction, the more the light reflected by the prism sheets 3J is directed outwards in the first direction relative to the reference ray L100, and exits from the second surface 12, which serves as the exit surface.

[0240] Furthermore, as a variation of embodiment 4, the plurality of prism sheets 3J can also be arranged in the imaginary grid Vg1 in the first surface 11. Figure 17A (Refer to) the grid points.

[0241] The various structures (including variations) described in Embodiment 4 can be appropriately combined with the various structures (including variations) described in Embodiments 1 to 3.

[0242] (Summarize)

[0243] The purpose of this disclosure is to provide optical systems, lighting systems, display systems, and moving bodies that can easily achieve desired brightness distributions.

[0244] The optical system (100, 100A to 100I) according to the first aspect of this disclosure includes a light guide member (1) and a plurality of prism sheets (3, 3A to 3I). The light guide member (1) has an incident surface (10) for light incidence and a first surface (11) and a second surface (12) opposite to each other, the second surface (12) being the light exit surface. The plurality of prism sheets (3, 3A to 3I) are disposed on the first surface (11) and reflect light passing through the interior of the light guide member (1) toward the second surface (12). The plurality of prism sheets (3, 3A to 3I) include two or more prism sheets (3, 3A to 3I) whose tilt angle (θ10) relative to the incident surface (10) is different at least according to their position along a first direction of both the incident surface (10) and the first surface (11). The tilt angle (θ10) of two or more prism sheets (3, 3A to 3I) is determined such that the more prism sheets (3, 3A to 3I) are located closer to the two ends of the first direction of the first face (11), the more the light emitted from the second face (12) is directed towards the outside or inside of the first direction relative to the reference ray (L100).

[0245] According to this disclosure, it has the advantage of easily achieving the desired brightness distribution.

[0246] Specifically, according to the first method, light incident from the incident surface (10) passes through the interior of the light guide member (1), is reflected by a plurality of prism sheets (3, 3A to 3I) disposed on the first surface (11) of the light guide member (1), and is emitted from the second surface (12) of the light guide member (1) which serves as the emission surface. Here, the tilt angle (θ10) of two or more of the plurality of prism sheets (3, 3A to 3I) relative to the incident surface (10) varies at least according to their position in the first direction, thereby controlling the direction of the light emitted from the second surface (12) by means of the tilt angle (θ10). Moreover, the tilt angle (θ10) is determined such that the closer the prism sheets (3, 3A to 3I) are to the two ends of the first surface (11) in the first direction, the more the light emitted from the second surface (12) is oriented towards the outside or inside of the first direction relative to the reference ray (L100). Therefore, the light emitted from the second surface (12), which serves as the emission surface, does not radiate in the same direction from the entire area of ​​the second surface (12). Instead, the light emitted is directed towards the outer or inner side of the second surface (12) as it approaches the two ends in the first direction. As a result, it has the advantage of being able to adjust the brightness distribution in the second surface (12), which serves as the emission surface, by adjusting the tilt angle (θ10) of the multiple prism sheets (3, 3A to 3I), thus easily achieving the desired brightness distribution.

[0247] Regarding the optical system (100, 100A to 100I) involved in the second method, in the first method, the light guide member (1) includes a direct light path (L1). The direct light path (L1) is a light path in which light incident from the incident surface (10) is directly reflected by any one of the multiple prism sheets (3, 3A to 3I) and emitted from the second surface (12).

[0248] This method can improve the efficiency of light extraction.

[0249] Regarding the optical system (100, 100A to 100I) involved in the third method, in the first or second method, the plurality of prism sheets (3, 3A to 3I) include a first group and a second group. The first group includes two adjacent prism sheets (3, 3A to 3I) in the first direction. The second group is located at the center in the first direction, farther away from the first surface (11) than the first group, and includes two adjacent prism sheets (3, 3A to 3I) in the first direction. In the first group and the second group, the spacing in the first direction is the same.

[0250] According to this method, it is possible to reduce the light reflection loss caused by the deviation of the spacing in the first direction of multiple prism sheets (3, 3A to 3I).

[0251] Regarding the optical system (100, 100A to 100I) involved in the fourth method, in the third method, the spacing in the first direction of the two adjacent prisms (3, 3A to 3I) among the plurality of prisms (3, 3A to 3I) is the same in all the prisms of the plurality of prisms (3, 3A to 3I).

[0252] According to this method, it is possible to reduce the light reflection loss caused by the deviation of the spacing in the first direction of multiple prism sheets (3, 3A to 3I).

[0253] Regarding the optical system (100, 100A to 100I) involved in the fifth method, in any of the methods from the first to the fourth, a plurality of prism sheets (3, 3A to 3I) are arranged on an imaginary arc (Va1) on the first surface (11).

[0254] This method makes it easy to design configurations of multiple prism sheets (3, 3A to 3I).

[0255] Regarding the optical system (100, 100A to 100I) involved in the sixth embodiment, in the fifth embodiment, the multiple prism sheets (3, 3A to 3I) include a third group and a fourth group. The third group includes two adjacent prism sheets (3, 3A to 3I) on the imaginary arc (Va1). The fourth group is located at the center in a first direction farther away from the first surface (11) than the third group, and includes two adjacent prism sheets (3, 3A to 3I) on the imaginary arc (Va1). In the third and fourth groups, the spacing along the imaginary arc (Va1) of the fourth group is wider.

[0256] According to this method, it is possible to reduce the light reflection loss caused by the deviation of the spacing in the first direction of multiple prism sheets (3, 3A to 3I).

[0257] Regarding the optical system (100, 100A to 100I) involved in the seventh method, in any of the first to fourth methods, multiple prism sheets (3, 3A to 3I) are arranged on the grid points of the imaginary grid (Vg1) in the first surface (11).

[0258] This method makes it easy to design configurations of multiple prism sheets (3, 3A to 3I).

[0259] Regarding the optical system (100, 100A to 100I) involved in the eighth method, in any of the methods from the first to the seventh, the length of each of the plurality of prism sheets (3, 3A to 3I) is the same in all the prism sheets of the plurality of prism sheets (3, 3A to 3I).

[0260] This method makes it easy to design configurations of multiple prism sheets (3, 3A to 3I).

[0261] Regarding the optical system (100, 100A to 100I) involved in the 9th method, in any of the 1st to 7th methods, the length of each of the plurality of prism sheets (3, 3A to 3I) is longer the closer it is to the two ends in the first direction of the first surface (11).

[0262] According to this method, it is possible to reduce the light reflection loss caused by the deviation of the spacing in the first direction of multiple prism sheets (3, 3A to 3I).

[0263] Regarding the optical system (100, 100A to 100I) involved in the 10th method, in any of the 1st to 9th methods, the plurality of prism sheets (3, 3A to 3I) include two or more prism sheets (3, 3A to 3I) with different heights from the first surface (11).

[0264] According to this method, the light reflection loss caused by the deviation in the spacing of multiple prism sheets (3, 3A to 3I) can be reduced.

[0265] Regarding the optical system (100, 100A to 100I) involved in the 11th method, in the 10th method, the height of each of the multiple prism sheets (3, 3A to 3I) is higher the closer it is to the two ends in the first direction of the first surface (11).

[0266] According to this method, the light reflection loss caused by the deviation in the spacing of multiple prism sheets (3, 3A to 3I) can be reduced.

[0267] Regarding the optical system (100, 100A to 100I) involved in the 12th method, in any of the methods 1 to 11, a strip prism (6, 6A to 6D) is also included. The strip prism (6, 6A to 6D) is arranged among two adjacent prism sheets (3, 3A to 3I) in a second direction orthogonal to the first direction within the first face (11). The strip prism (6, 6A to 6D) has a length that spans more than two adjacent prism sheets (3, 3A to 3I) in the first direction.

[0268] According to this method, it is possible to reduce the light reflection loss caused by the deviation of the spacing in the first direction of multiple prism sheets (3, 3A to 3I).

[0269] Regarding the optical system (100, 100A to 100I) involved in Method 13, Method 12 includes multiple elongated prisms (6, 6A to 6D). The lengths of the multiple elongated prisms (6, 6A to 6D) are different.

[0270] According to this method, it is possible to reduce the light reflection loss caused by the deviation of the spacing in the first direction of multiple prism sheets (3, 3A to 3I).

[0271] Regarding the optical system (100, 100A to 100I) involved in the 14th mode, in any of the 1st to 13th modes, light from a plurality of light sources (4) arranged in the first direction is incident on the incident surface (10).

[0272] This method has the advantage of easily achieving the desired brightness distribution.

[0273] The lighting system (200) according to the 15th method includes: an optical system (100, 100A to 100I) according to any one of the 1 to 14 methods; and a light source (4) that outputs light incident on the incident surface (10).

[0274] This method has the advantage of easily achieving the desired brightness distribution.

[0275] The display system (300) according to the 16th method includes: the lighting system (200) according to the 15th method; and the display (5) which receives light emitted from the lighting system (200) to display an image.

[0276] This method has the advantage of easily achieving the desired brightness distribution.

[0277] The mobile body (B1) according to the 17th method includes: the display system (300) according to the 16th method; and the mobile body (B11) equipped with the display system (300).

[0278] This method has the advantage of easily achieving the desired brightness distribution.

[0279] The structures involved in methods 2 to 14 are not essential structures in the optical system (100, 100A to 100I) and can be appropriately omitted.

Claims

1. An optical system comprising: A light guide component has an incident surface for light incidence and a first surface and a second surface that are opposite each other, wherein the second surface is a light emission surface; Multiple prism sheets, disposed on the first surface, reflect light passing through the interior of the light guide member toward the second surface; and Long strip prism, The plurality of prism sheets include: The tilt angle relative to the incident surface varies at least two prism sheets depending on their position along a first direction of both the incident surface and the first surface. The tilt angle of the two or more prisms is determined such that the closer they are to the two ends in the first direction of the first face, the more the light emitted from the second face is directed towards the outside or inside of the first direction relative to the reference ray. The elongated prism is disposed among the plurality of prism sheets, between two adjacent prism sheets in the first face along a second direction orthogonal to the first direction, and has a length that spans more than two adjacent prism sheets in the first direction.

2. The optical system according to claim 1, wherein, The light guide component includes a direct light path in which light incident from the incident surface is directly reflected by any one of the plurality of prism sheets, causing it to exit from the second surface.

3. The optical system according to claim 1 or 2, wherein, The plurality of prism sheets include: The first group comprises two adjacent prism sheets in the first direction; and The second group, located at the center of the first face in the first direction, is farther away from the first group than the first group, and includes two adjacent prism sheets in the first direction. In both the first group and the second group, the spacing in the first direction is the same.

4. The optical system according to claim 3, wherein, The spacing in the first direction between two adjacent prisms in the plurality of prism sheets is the same in all the prism sheets in the plurality of prism sheets.

5. The optical system according to claim 1 or 2, wherein, The plurality of prism sheets are arranged on an imaginary arc in the first face.

6. The optical system according to claim 5, wherein, The plurality of prism sheets include: The third group comprises two adjacent prism sheets on the imaginary arc; and The fourth group, located at the center of the first direction further away from the first surface than the third group, includes two adjacent prism sheets on the imaginary arc. In the third and fourth groups, the spacing along the imaginary arc is wider in the fourth group.

7. The optical system according to claim 1 or 2, wherein, The plurality of prism sheets are arranged on grid points of the imaginary grid in the first face.

8. The optical system according to claim 1 or 2, wherein, The length of each of the plurality of prism sheets is the same in all of the plurality of prism sheets.

9. The optical system according to claim 1 or 2, wherein, Regarding the length of each of the plurality of prism sheets, the closer they are to the two ends in the first direction of the first face, the longer the length.

10. The optical system according to claim 1 or 2, wherein, The plurality of prism sheets includes two or more prism sheets at different heights from the first face.

11. The optical system according to claim 10, wherein, Regarding the height of each of the plurality of prism sheets, the higher the height is located closer to the two ends of the first face in the first direction.

12. The optical system according to claim 1 or 2, wherein, The elongated prism is formed as a straight line parallel to the first direction.

13. The optical system according to claim 1 or 2, wherein, Multiple elongated prisms are provided. The lengths of the various elongated prisms are different.

14. The optical system according to claim 1 or 2, wherein, Light from a plurality of light sources arranged in the first direction is incident on the incident surface.

15. A lighting system comprising: The optical system according to any one of claims 1 to 14; and A light source that outputs light incident on the incident surface.

16. A display system comprising: The lighting system of claim 15; and A display receives light emitted from the lighting system to display an image.

17. A mobile body, comprising: The display system of claim 16; and The main body of the mobile device is equipped with the display system.

Images