Optical systems, lighting systems, display systems, and mobile devices

Abstract

This optical system comprises a light guiding member, a prism, and a plurality of light control bodies. The light guiding member has an entry surface into which light enters, and a first surface and a second surface which face each other. In the light guiding member, the second surface is a light exit surface. The prism is provided to the first surface and reflects, toward the second surface, light that has passed through the inside of the light guiding member. The plurality of light control bodies are positioned between a light source and the entry surface. The plurality of light control bodies control light that is output from the light source and that enters the entry surface. Each of the plurality of light control bodies is provided with an entry lens. Each of the light control bodies causes light that has entered the entry lens from the light source to enter the entry surface. The direction of the optical axis of light that is made to enter the entry surface differs for at least two of the plurality of light control bodies.

Description

Technical Field

[0001] The present disclosure generally relates to optical systems, lighting systems, display systems, and mobile bodies. More specifically, the present disclosure relates to optical systems, lighting systems, display systems, and mobile bodies that control light incident from an incident surface and emit it from an exit surface.

Background Art

[0002] Patent Document 1 discloses an image display device (display system) that projects a virtual image onto a target space. This image display device is a head-up display (HUD) device for automobiles. Projection light, which is image light emitted from an in-vehicle HUD device (optical system) within a dashboard, is reflected by a windshield and directed toward a driver who is the viewer. As a result, the user (driver) can visually recognize an image such as a navigation image as a virtual image and visually recognize it as if the virtual image is superimposed on a background such as a road surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] An optical system according to one aspect of the present disclosure comprises a light guide member, a prism, and a plurality of light control units. The light guide member has an incident surface into which light is incident, and a first surface and a second surface facing each other. The second surface of the light guide member is the light exit surface. The prism is provided on the first surface and reflects light passing through the interior of the light guide member toward the second surface. The plurality of light control units are located between the light source and the incident surface. The plurality of light control units control the light output from the light source that is incident on the incident surface. Each of the plurality of light control units includes an incident lens. Each of the plurality of light control units causes the light incident on the incident surface from the light source to be incident on the incident surface. The directions of the optical axes of the light incident on the incident surface by at least two of the plurality of light control units are different from each other. The incident lens includes a plurality of lens sections with different curvature distributions. Each of the plurality of light control units causes the light incident from the light source onto each of the plurality of lens sections to be incident on the incident surface. At least two of the plurality of lens sections have different optical axis directions for the light incident on the incident surface. [Brief explanation of the drawing]

[0005] [Figure 1A] Figure 1A is a side cross-sectional view showing an overview of the optical system according to the embodiment. [Figure 1B] Figure 1B is a schematic diagram showing an enlarged view of region F1 in Figure 1A. [Figure 2] Figure 2 is a side cross-sectional view showing an overview of the optical control unit of the optical system described above. [Figure 3A] Figure 3A is a plan cross-sectional view illustrating the direction of the optical axis of light in the optical system described above. [Figure 3B] Figure 3B is a side cross-sectional view illustrating the direction of the optical axis of light in the optical system described above. [Figure 4] Figure 4 is a perspective view showing an overview of the optical system described above. [Figure 5] Figure 5 is an explanatory diagram of a display system using the optical system described above. [Figure 6] Figure 6 is an explanatory diagram of a mobile device equipped with the same display system. [Figure 7A] Figure 7A is a plan view of the optical system described above. [Figure 7B] Figure 7B is a front view of the optical system described above. [Figure 7C] Figure 7C is a bottom view of the optical system shown above. [Figure 7D] Figure 7D is a side view of the optical system shown above. [Figure 8A] Figure 8A is a schematic diagram showing an enlarged view of region A1 in Figure 7C. [Figure 8B] Figure 8B is a cross-sectional view taken along the line B1-B1 in Figure 8A. [Figure 9] Figure 9 is a schematic plan view showing the brightness distribution of the emitted light in the comparative optical system. [Figure 10] Figure 10 is a schematic plan view showing the brightness distribution of the emitted light in the optical system of the embodiment. [Figure 11] Figure 11 is a front view illustrating the outline of the optical control unit of the optical system described above. [Figure 12] Figure 12 is a side cross-sectional view illustrating the optical path in the optical control body of the optical system described above. [Figure 13] Figure 13 is a side cross-sectional view illustrating the optical path in the optical control body of the optical system described above. [Figure 14] Figure 14 is a front view showing an overview of the optical control unit according to Modification 1. [Modes for carrying out the invention]

[0006] In image display devices such as those described in Patent Document 1, there was a possibility of unevenness in the brightness of the image viewed by the user.

[0007] This disclosure is made in view of the above-mentioned reasons and aims to provide an optical system, lighting system, display system, and mobile device that can reduce unevenness in the brightness of images viewed by the user.

[0008] The optical system 100 (see FIG. 1A), the illumination system 200, the display system 300 (see FIG. 5), and the moving body B1 (see FIG. 6) according to the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. Even outside these embodiments and modifications, various changes can be made according to the design and the like as long as the technical idea of the present disclosure is not deviated. In addition, each figure described in the following embodiments is a schematic figure, and the ratio of the size and thickness of each component in the figure does not necessarily reflect the actual dimensional ratio. Further, the following embodiments (including modifications) may be realized in appropriate combination.

[0009] (1) Overview First, an overview of the optical system 100 according to the present embodiment and the illumination system 200 using the optical system 100 will be described with reference to FIGS. 1A to 4.

[0010] The optical system 100 (see FIGS. 1A and 1B) according to the present embodiment has a function of controlling the light incident from the incident surface 10 and emitting it from the emission surface (the second surface 12). As shown in FIGS. 1A and 1B, the optical system 100 includes a light guide member 1, a plurality of light control bodies 2, and a prism 3.

[0011] The optical system 100 constitutes the illumination system 200 together with the light source 4. In other words, the illumination system 200 according to the present embodiment includes the optical system 100 and the light source 4.

[0012] The light source 4 outputs the light incident on the incident surface 10. Although it will be described in detail later, when the optical system 100 includes a plurality of light control bodies 2, the light from the light source 4 does not directly enter the light guide member 1, but enters the light guide member 1 through the light control bodies 2. That is, the light emitted from the light source 4 enters the incident surface 10 (of the light guide member 1) through the light control bodies 2.

[0013] Thus, in this embodiment, the optical system 100 further comprises a plurality of light control units 2 in addition to the light guide member 1 and the prism 3. The plurality of light control units 2 are positioned between the light source 4 and the incident surface 10 of the light guide member 1 and control the light output from the light source 4 that is incident on the incident surface 10. In particular, in this embodiment, the light guide member 1 and the plurality of light control units 2 are integrated as a single molded product. In other words, in this embodiment, the light guide member 1 and the plurality of light control units 2 are a single molded product and are inseparable. To put it another way, the plurality of light control units 2 are seamlessly continuous with respect to the incident surface 10 of the light guide member 1, and the light guide member 1 and the plurality of light control units 2 are seamlessly integrated. Therefore, in this embodiment, the incident surface 10 of the light guide member 1 is a "virtual surface" defined inside the single molded product of the light guide member 1 and the plurality of light control units 2, and does not have a physical body.

[0014] In this embodiment, the light guide member 1 has an incident surface 10 into which light is incident, and a first surface 11 and a second surface 12 that face each other. The second surface 12 is the light exit surface. The prism 3 is provided on the first surface 11. The prism 3 reflects the light passing through the inside of the light guide member 1 toward the second surface 12.

[0015] Furthermore, as shown in Figure 2, in this embodiment, each of the multiple light control units 2 is equipped with an incident lens 21. Each of the multiple light control units 2 directs the light incident from the light source 4 into the incident lens 21 and causes it to be incident on the incident surface 10.

[0016] The incident lens 21 has a main incident surface 211 and a secondary incident surface 212. The main incident surface 211 is positioned opposite the light source 4. The secondary incident surface 212 is directed toward the normal L21 of the main incident surface 211. Here, the normal L21 of the main incident surface 211 is, for example, the normal of the main incident surface 211 at its tip (the apex of the dome) if the main incident surface 211 is dome-shaped. The normal L21 of the main incident surface 211 is a "virtual line" and does not have a physical form. The secondary incident surface 212 is located in at least a part of the periphery of the main incident surface 211. Here, as shown in Figure 1A, the optical axis P1 of the light incident from the light source 4 (first incident light LT1) coincides with the normal L21 of the main incident surface 211. Also, the optical axis P1 is parallel to the second surface 12.

[0017] Furthermore, each of the multiple optical control units 2 can control the direction of the optical axis P1 of the first incident light LT1. In detail, as shown in Figures 3A and 3B, the first incident light LT1 with optical axis P1 is incident on the incident surface 10 as the second incident light LT2 with optical axis P2, passing through each of the multiple optical control units 2. Here, optical axes P1 and P2 may intersect or may be parallel. Here, "intersecting" is synonymous with the angle between optical axes P1 and P2 being greater than 0 degrees. Also, as will be described in detail later, the first incident light LT1 is brought closer to parallel light by the optical control unit 2 and incident on the incident surface 10 as the second incident light LT2.

[0018] In this embodiment, the direction of the optical axis P2 of the second incident light LT2 incident on the incident surface 10 by at least two of the multiple optical control bodies 2 is different from that of the other. For example, in this embodiment, the optical system 100 comprises seven optical control bodies 2 (optical control bodies 2A to 2G). Each of the optical control bodies 2A to 2G is located between a plurality of light sources 4 (light sources 4A to 4G) corresponding one-to-one and the incident surface 10 of the light guide member 1. The optical control bodies 2A to 2G are also aligned in the width direction of the light guide member 1 (the direction in which light sources 4A to 4G are aligned in Figure 4). Furthermore, the direction of the optical axis P2 (optical axis P2A to optical axis P2G) of the second incident light LT2 (second incident light LT2A to second incident light LT2G) incident on the incident surface 10 from each of the optical control bodies 2A to 2G is different from that of the other.

[0019] First incident light LT1 (first incident light LT1A to first incident light LT1G) is incident on each of the optical control units 2A to 2G from each of the light sources 4A to 4G. At this time, as shown in Figures 3A and 3B, the optical axes P1 (optical axis P1A to optical axis P1G) of the first incident light LT1A to first incident light LT1G are all equal in direction and parallel to each other. Also, optical axes P1A to optical axis P1G are parallel to the second surface 12 and perpendicular to the incident surface 10. Here, the first incident light LT1A to first incident light LT1G is converted into parallel light by the incident lens 21 provided in each of the optical control units 2A to 2G, and incident on the incident surface 10 as second incident light LT2A to second incident light LT2G, each having an optical axis P2 (optical axis P2A to optical axis P2G). Note that optical axes P1 and P2 may intersect or may be parallel. For example, as shown in Figures 3A and 3B, the optical axis P2A of the second incident light LT2A lies on the optical axis P1A of the first incident light LT1A, and optical axes P1A and P2A are parallel. Also, optical axes P2A to P2G intersect each other. In other words, the directions of optical axes P2A to P2G are different.

[0020] Thus, the optical system 100 can control the luminance distribution of the emitted light emitted from the emission surface (second surface 12) by controlling each direction of the optical axis P2A to P2G using optical control units 2A to 2G, for example, as shown in Figures 3A and 3B. The directions of the optical axis P2A to P2G shown in Figures 3A and 3B are examples, and the directions of the optical axis P2A to P2G can be changed as appropriate so that the emitted light emitted from the second surface 12 has a desired luminance distribution. Here, the emitted light is the planar light created by the second incident light LT2A to LT2G reflected by the prism 3, and the luminance distribution of the emitted light is the light intensity distribution of the emitted light on the second surface 12.

[0021] (2)Details The optical system 100, the lighting system 200 using the optical system 100, the display system 300 using the lighting system 200, and the mobile body B1 according to this embodiment will be described in detail below with reference to Figures 1A to 13.

[0022] (2.1) Premise In the following description, the width direction of the light guide member 1 (the direction in which the multiple light sources 4 are aligned in Figure 4) will be referred to as the "X-axis direction," and the depth direction of the light guide member 1 (the direction in which light from the light source enters the incident surface 10 in Figure 1A) will be referred to as the "Y-axis direction." Furthermore, in the following description, the thickness direction of the light guide member 1 (the direction in which the first surface 11 and the second surface 12 are aligned in Figure 1A) will be referred to as the "Z-axis direction." The X, Y, and Z axes that define these directions are orthogonal to each other. The arrows indicating the "X-axis direction," "Y-axis direction," and "Z-axis direction" in the drawings are for illustrative purposes only and do not represent actual objects.

[0023] Furthermore, the term "extraction efficiency" as used in this disclosure refers to the ratio of the amount of light emitted from the second surface 12 (exit surface) of the light guide member 1 to the amount of light of the second incident light LT2 incident on the incident surface 10 of the light guide member 1. In other words, the larger 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 of the second incident light LT2 incident on the incident surface 10 of the light guide member 1, the higher the light extraction efficiency. For example, if the amount of light of the second incident light LT2 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 of the light guide member 1 will be 10%.

[0024] Furthermore, the term "optical axis" as used in this disclosure refers to a hypothetical ray that represents the light beam passing through the entire system. For example, the optical axis P1A of the first incident light LT1A that enters the optical control unit 2A from the light source 4A coincides with the rotational symmetry axis of the first incident light LT1A.

[0025] Furthermore, as used in this disclosure, "parallel" refers not only to cases where the two parties are approximately parallel, that is, strictly parallel, but also to cases where the angle between the two parties falls within a range of a few degrees (for example, less than 2 degrees).

[0026] Furthermore, the term "orthogonal" as used in this disclosure refers not only to cases where the two parties are approximately orthogonal, that is, strictly orthogonal, but also to cases where the angle between the two parties falls within a range of a few degrees (for example, less than 2 degrees) relative to 90 degrees.

[0027] (2.2) Display System First, the display system 300 will be explained with reference to Figures 5 and 6.

[0028] As shown in Figure 5, the lighting system 200 according to this embodiment constitutes a display system 300 together with the display unit 5. In other words, the display system 300 according to this embodiment comprises the lighting system 200 and the display unit 5. The display unit 5 receives light emitted from the lighting system 200 and displays an image. The term "image" here refers to an image displayed in a manner that is visible to the user U1 (see Figure 6), and may be a graphic, symbol, character, number, pattern, or photograph, or a combination thereof. The images displayed in the display system 300 include moving images and still images. Furthermore, "moving images" include images composed of multiple still images obtained by stop-motion animation or the like.

[0029] Furthermore, as shown in Figure 6, the display system 300 according to this embodiment constitutes a mobile body B1, such as an automobile, together with the mobile body B11. In other words, the mobile body B1 according to this embodiment comprises the display system 300 and the mobile body B11. The mobile body B11 is equipped with the display system 300. In this embodiment, as an example, the mobile body B1 is an automobile (passenger car) driven by a person. The mobile body B1 may also be an autonomous vehicle capable of driving automatically. In this case, the user U1 who views the image displayed on the display system 300 is an occupant of the mobile body B1, and in this embodiment, as an example, it is assumed that the driver of the automobile as the mobile body B1 is the user U1.

[0030] In this embodiment, the display system 300 is used, for example, as a head-up display (HUD) mounted on a mobile vehicle B1. The display system 300 is used to display, for example, driving assistance information related to the speed information, condition information, and driving information of the mobile vehicle B1 in the field of view of the user U1. The driving information of the mobile vehicle B1 includes, for example, navigation-related information that displays the driving route, and ACC (Adaptive Cruise Control)-related information that maintains a constant driving speed and distance between vehicles.

[0031] As shown in Figures 5 and 6, the display system 300 comprises an image display unit 310, an optical system 320, and a control unit 330. The display system 300 further comprises a housing 340 that accommodates the image display unit 310, the optical system 320, and the control unit 330.

[0032] The housing 340 is made of, for example, a molded product of synthetic resin. The housing 340 houses the image display unit 310, the optical system 320, and the control unit 330, etc. The housing 340 is mounted on the dashboard B13 of the mobile body B11. Light reflected by the second mirror 322 (described later) of the optical system 320 is emitted through an opening on the top surface of the housing 340 to a reflective member (windshield B12), and the light reflected by the windshield B12 is focused onto the eye box C1. The reflective member is not limited to the windshield B12, but may be realized by, for example, a combiner placed on the dashboard B13 of the mobile body B11.

[0033] With such a display system 300, user U1 will view a virtual image projected into the space in front of the mobile body B1 (outside the vehicle) through the windshield B12. In this disclosure, "virtual image" means an image formed as if an actual object were present when light emitted from the display system 300 is diverged by a reflective material such as the windshield B12. Therefore, user U1, who is driving the mobile body B1, views the image as a virtual image projected by the display system 300 superimposed on the real space extending in front of the mobile body B1. In short, the display system 300 according to this embodiment displays a virtual image as an image. The images (virtual images) that the display system 300 can display include a virtual image E1 superimposed along the driving surface D1 of the mobile body B1, and a virtual image drawn three-dimensionally along a plane PL1 perpendicular to the driving surface D1.

[0034] The image display unit 310 includes a case 311. The image display unit 310 has the function of displaying a stereoscopic image using a light field method, which reproduces light emitted from an object in an image in multiple directions to make the object appear three-dimensional. However, the method by which the image display unit 310 displays the virtual image of the object being drawn in three dimensions is not limited to the light field method. The image display unit 310 may also employ a parallax method, which projects images with parallax to the left and right eyes of the user U1, respectively, to allow the user U1 to see the virtual image of the object being drawn in three dimensions.

[0035] The image display unit 310 comprises a display unit 5 and an illumination system 200 including an optical system 100. The display unit 5 is, for example, a liquid crystal display, and displays an image by receiving light emitted from the illumination system 200. In other words, the illumination system 200 emits light from behind the display unit 5 toward the display unit 5, and the display unit 5 displays an image as the light from the illumination system 200 passes through the display unit 5. To put it another way, the illumination system 200 functions as a backlight for the display unit 5.

[0036] The image display unit 310 comprises a case 311. The case 311 houses an illumination system 200 including an optical system 100 and a light source 4, and a display unit 5. The illumination system 200 and the display unit 5 are held in place by the case 311. Here, the display unit 5 is positioned along the top surface of the case 311, with one side of the display unit 5 exposed from the top surface of the case 311. The illumination system 200 is positioned below the display unit 5 within the case 311 and emits light from below the display unit 5 toward the display unit 5. As a result, the top surface of the case 311 constitutes a display surface 312 on which an image is displayed.

[0037] The image display unit 310 is housed inside the housing 340 with its display surface 312 facing the first mirror 321 (described later). The display surface 312 of the image display unit 310 is shaped to match the range of the image to be projected onto the user U1, that is, the shape of the windshield B12 (for example, rectangular). 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 according to the control unit 330, and an image is displayed on the display surface 312 by the light output from the display surface 312 of the image display unit 310.

[0038] The image displayed on the display surface 312 of the image display unit 310 is emitted to the windshield B12, and the light reflected by the windshield B12 is focused onto the eye box C1. In other words, the image displayed on the display surface 312 is viewed by the user U1, whose viewpoint is inside the eye box C1, through the optical system 320. At this time, the user U1 will be viewing a virtual image projected into the space in front of the moving object B1 (outside the vehicle) through the windshield B12.

[0039] The optical system 320 focuses the light output from the display surface 312 of the image display unit 310 onto the eye box C1. In this embodiment, the optical system 320 includes, for example, a first mirror 321 which is a convex mirror, a second mirror 322 which is a concave mirror, and a windshield B12.

[0040] The first mirror 321 reflects the light output from the image display unit 310 and directs it to the second mirror 322. The second mirror 322 reflects the light incident from the first mirror 321 toward the windshield B12. The windshield B12 reflects the light incident from the second mirror 322 and directs it to the eye box C1.

[0041] The control unit 330 includes, for example, a computer system. The computer system mainly consists of one or more processors and one or more memories as hardware. The functions of the control unit 330 (for example, functions of the drawing control unit 331, image data creation unit 332, and output unit 333, etc.) are realized by one or more processors executing a program recorded in one or more memories or storage units 334 of the computer system. The program is pre-recorded in one or more memories or storage units 334 of the computer system. The program may be provided via a telecommunications line, or it may be provided recorded on a non-temporary recording medium such as a memory card, optical disk, or hard disk drive that can be read by the computer system.

[0042] The memory unit 334 is implemented using, for example, a non-temporary recording medium such as a rewritable non-volatile semiconductor memory. The memory unit 334 stores programs and the like that executed by the control unit 330. As already mentioned, the display system 300 is used to display driving support information related to the speed information, condition information, and driving information of the mobile body B1 in the field of view of the user U1. For this reason, the types of virtual images displayed by the display system 300 are predetermined. The memory unit 334 has image data for displaying virtual images (virtual image E1 which is the object to be drawn in planar form, and virtual image which is the object to be drawn in three dimensions) stored in advance.

[0043] The drawing control unit 331 receives detection signals from various sensors 350 mounted on the mobile body B1. The sensors 350 are, for example, sensors for detecting various types of information used in an Advanced Driver Assistance System (ADAS). The sensors 350 include, for example, at least one of a sensor for detecting the state of the mobile body B1 and a sensor for detecting the state of the surroundings of the mobile body B1. The sensor for detecting the state of the mobile body B1 includes, for example, a sensor for measuring the vehicle speed, temperature, or remaining fuel of the mobile body B1. The sensor for detecting the state of the surroundings of the mobile body B1 includes an image sensor that captures images of the surroundings of the mobile body B1, a millimeter-wave radar, or LiDAR (Light Detection and Ranging), etc.

[0044] The drawing control unit 331 acquires one or more image data from the storage unit 334 for displaying information related to the detection signal input from the sensor 350. When displaying multiple types of information on the image display unit 310, the drawing control unit 331 acquires multiple image data for displaying multiple types of information. The drawing control unit 331 also determines positional information regarding the position where the virtual image is displayed in the target space where the virtual image is displayed, based on the detection signal input from the sensor 350. The drawing control unit 331 then outputs the image data and positional information of the virtual image to be displayed to the image data creation unit 332.

[0045] The image data creation unit 332 creates image data for displaying a virtual image of the object to be displayed, based on the image data and position information input from the drawing control unit 331.

[0046] The output unit 333 outputs the image data created by the image data creation unit 332 to the image display unit 310, and displays an image based on the created image data on the display surface 312 of the image display unit 310. The image displayed on the display surface 312 is projected onto the windshield B12, so that the display system 300 displays an image (virtual image). In this way, the image (virtual image) displayed by the display system 300 is visible to the user U1.

[0047] (2.3) Optical Systems Next, the optical system 100 will be described with reference to Figures 1A to 4 and Figures 7A to 10.

[0048] In this embodiment, the optical system 100 comprises a light guide member 1, a plurality of light control units 2 (light control units 2A to 2G), and a plurality of prisms 3. That is, the optical system 100 according to this embodiment comprises a plurality of light control units 2, and further comprises a plurality of prisms 3.

[0049] Furthermore, in this embodiment, the optical system 100, together with the light sources 4A to 4G, constitutes the illumination system 200. That is, the illumination system 200 according to this embodiment comprises the optical system 100 and the light sources 4A to 4G.

[0050] Since the multiple light sources 4 (light sources 4A to 4G) employ a common configuration, unless otherwise specified, the configuration described for one light source 4 is also applicable to the other light sources 4.

[0051] The light source 4 is a solid-state light-emitting element such as a light-emitting diode (LED) or an organic electro-luminescence (OEL) element. In this embodiment, as an example, the light source 4 is a chip-shaped light-emitting diode element. In reality, such a light source 4 emits light over a certain area of ​​its surface (light-emitting surface), but ideally, it can be considered a point light source that emits light from a single point on its surface. Therefore, in the following explanation, the light source 4 will be described assuming that it is an ideal point light source.

[0052] In this embodiment, as shown in Figure 2, the light source 4 is positioned opposite the incident surface 10 of the light guide member 1 at a predetermined distance. The light control unit 2 is positioned between the light source 4 and the incident surface 10 of the light guide member 1.

[0053] In this embodiment, the light control body 2 is integrated with the light guide member 1. In this disclosure, "integrated" means a configuration in which multiple elements (parts) can be treated as a single physical unit. In other words, multiple elements being integrated means that multiple elements are combined into one and can be treated as a single component. In this case, the multiple elements may be inseparable, like a single molded product, or multiple elements created separately may be mechanically joined together, for example, by welding, bonding, or crimping. That is, the light guide member 1 and the light control body 2 can be integrated in any appropriate manner.

[0054] 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. In other words, in this embodiment, the light guide member 1 and the light control body 2 are a single molded product and are inseparable. Therefore, as described above, the incident surface 10 of the light guide member 1 is a "virtual surface" defined inside the single molded product of the light guide member 1 and the light control body 2, and does not have a physical body.

[0055] Here, the light sources 4A to 4G are arranged in a line with a predetermined interval in the X-axis direction, as shown in Figure 4. The light sources 4A to 4G correspond one-to-one with the multiple light control units 2A to 2G. In other words, the light control units 2A to 2G are also arranged in a line in the X-axis direction, similar to the light sources 4A to 4G. Here, the pitch of the light sources 4A to 4G in the X-axis direction is equal to the pitch of the light control units 2A to 2G.

[0056] The light guide member 1 is a member that guides light from the light source 4, taking it into the light guide member 1 from the incident surface 10 and guiding it through the light guide member 1 to the second surface 12, which is the exit surface. In this embodiment, the light guide member 1 is, for example, a molded product of a light-transmitting resin material such as acrylic resin, and is formed in the shape of a plate. In other words, the light guide member 1 is a light guide plate having a certain thickness.

[0057] As described above, the light guide member 1 has an incident surface 10 into which light is incident, and a first surface 11 and a second surface 12 (exit surface) that face each other. Furthermore, the light guide member 1 has an end surface 13 that faces the incident surface 10.

[0058] Specifically, in this embodiment, as shown in Figures 7A to 7D, the light guide member 1 is rectangular in shape, and the two opposing surfaces in the thickness direction of the light guide member 1 are the first surface 11 and the second surface 12, respectively. In addition, one of the four end faces (circumferential surfaces) of the light guide member 1 is the incident surface 10. In other words, the light guide member 1 is formed in a rectangular shape in a plan view (viewed from one side in the Z-axis direction). Here, as an example, the light guide member 1 is formed in a rectangular shape in which the dimension in the Y-axis direction is smaller than the dimension in the X-axis direction. Furthermore, both surfaces in the thickness direction (Z-axis direction) of the light guide member 1 constitute the first surface 11 and the second surface 12, respectively. In addition, both 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.

[0059] Thus, one of the two end faces of the light guide member 1 that face each other in the Y-axis direction (the left face in Figure 1A) is the incident surface 10 through which the first incident light LT1 (first incident light LT1A to first incident light LT1G) emitted from light sources 4A to 4G respectively passes through the light control units 2A to 2G and is incident as the second incident light LT2 (second incident light LT2A to second incident light LT2G). The two faces of the light guide member 1 that face each other in the Z-axis direction are the first surface 11 and the second surface 12, respectively. The first surface 11 is the bottom surface in Figure 1A, and the second surface 12 is the top surface in Figure 1A. The second surface 12 is the exit surface that emits light from the inside to the outside of the light guide member 1. Therefore, when the second incident light LT2 is incident on the end face that is the incident surface 10 of the light guide member 1, the second surface 12, which is the exit surface, emits light from the surface.

[0060] Furthermore, in this embodiment, the second surface 12 is a plane parallel to the XY plane. Also, the incident surface 10 is a plane parallel to the XZ plane. Here, the "XY plane" is a plane that includes the X and Y axes and is perpendicular to the Z axis. Similarly, the "XZ plane" is a plane that includes the X and Z axes and is perpendicular to the Y axis. Since the second surface 12 is a plane perpendicular to the Z axis and the incident surface 10 is a plane perpendicular to the Y axis, the second surface 12 and the incident surface 10 are perpendicular to each other.

[0061] On the other hand, the first surface 11 is not parallel to the XY plane, but is inclined with respect to the XY plane. In other words, the first surface 11 and the incident surface 10 are not orthogonal to each other. Specifically, the first surface 11 is inclined with respect to the XY plane such that it approaches the second surface 12 as it moves away from the incident surface 10. In other words, in this embodiment, the first surface 11 and the second surface 12 are inclined to each other.

[0062] Furthermore, in this embodiment, as shown in Figure 1A, the end face 13 is, for example, parallel to the incident surface 10.

[0063] Furthermore, in this embodiment, a light distribution control unit 14 is provided on the second surface 12. The light distribution control unit 14 includes a lens. In this embodiment, as an example, it includes a cylindrical lens. The light distribution control unit 14 will be described in detail in the section "(2.7) Light Distribution Control Unit". Note that the light distribution control unit 14 is not an essential component of the optical system 100 and can be omitted as appropriate.

[0064] The light control unit 2 is positioned 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 that enters the incident surface 10. In this embodiment, the light control unit 2 has a collimating function that brings the first incident light LT1 output from the light source 4 closer to parallel light. That is, when the first incident light LT1, which spreads radially from the light source 4, enters the light control unit 2, it is a collimating lens that focuses this first incident light LT1 toward the incident surface 10, thereby bringing it closer to parallel light. Here, the first incident light LT1 emitted from the light source 4 enters the incident surface 10 of the light guide member 1 through the light control unit 2. Therefore, the first incident light LT1 from the light source 4 is controlled by the light control unit 2, which has a collimating function, to narrow its divergence angle, and is emitted toward the incident surface 10 of the light guide member 1 as the second incident light LT2. In this embodiment, we will explain assuming that the first incident light LT1 from the light source 4, which is an ideal point light source, is converted by the light control unit 2 into the second incident light LT2, which is an ideal parallel light.

[0065] In this embodiment, as shown in Figure 4, multiple light control units 2 (light control units 2A to 2G) are formed so as to be aligned in the X-axis direction at the end portion constituting the incident surface 10 of the light guide member 1. In other words, in this embodiment, the light control units 2 are integrated with the light guide member 1. Furthermore, as already mentioned, each of the light control units 2A to 2G corresponds one-to-one with one of the multiple light sources 4 (light sources 4A to 4G). Therefore, each of the light control units 2A to 2G controls the divergence angle of the first incident light LT1 (first incident light LT1A to first incident light LT1G) emitted by the corresponding light source 4, and causes the parallel light, the second incident light LT2 (second incident light LT2A to second incident light LT2G), to be incident on the incident surface 10. Also, as described above, in this embodiment, the directions of the optical axes P2 (optical axis P2A to optical axis P2G) of the second incident light LT2A to second incident light LT2G are different from each other.

[0066] In this embodiment, the angles between optical axis P2A and optical axes P2B to P2G are preferably greater than 0 degrees and within 15 degrees, and more preferably between 1 degree and 10 degrees. Details of the function of the optical control unit 2 will be explained in the section "(2.4) Optical Control Unit".

[0067] The prism 3 is provided on the first surface 11 and reflects the light passing through the inside of the light guide member 1 toward the second surface 12. In this embodiment, multiple prisms 3 are provided on the first surface 11. The prism 3 is configured to totally reflect the incoming second incident light LT2. Of course, the prism 3 is not limited to totally reflecting all of the incoming second incident light LT2, but may also include a configuration in which a portion of the second incident light LT2 passes through the inside of the prism 3 without totally reflecting and exits to the outside of the light guide member 1.

[0068] In the light guide member 1, most of the second incident light LT2 incident from the incident surface 10 is not reflected by the portion of the first surface 11 or the second surface 12 excluding the prism 3, but is reflected by the prism 3 and emitted from the second surface 12. In other words, the light guide member 1 includes a direct optical path L1 that directly reflects the second incident light LT2 incident from the incident surface 10 by the prism 3 and emits it as emitted light from the second surface 12.

[0069] In this embodiment, the prism 3 is formed on the first surface 11 such that its cross-section, when viewed from one side in the X-axis direction, is a triangular recess. The prism 3 is formed, for example, by processing the first surface 11 of the light guide member 1. As shown in Figure 1B, the prism 3 has a reflective surface 30 that reflects the second incident light LT2, which enters through the inside of the light guide member 1, toward the second surface 12. Figure 1B is a schematic end view that enlarges region F1 of Figure 1A.

[0070] The angle θ1 between the reflective surface 30 and the first surface 11 (i.e., the inclination angle of the reflective surface 30) is such that the incident angle θ0 of the second incident light LT2 incident on the reflective surface 30 is greater than or equal to the critical angle. In other words, the reflective surface 30 is inclined with respect to the first surface 11 so that the incident second incident light LT2 undergoes total internal reflection. In this embodiment, the inclination angle θ1 of the reflective surface 30 is set so that the light totally reflected by the reflective surface 30 is incident on the second surface 12 in a direction perpendicular to it, for example. In this embodiment, multiple second incident light LT2 (second incident light LT2A to second incident light LT2G) are incident on the first surface 11. Since the optical axes P2A and P2G of the second incident light LT2A and LT2G are in different directions, the tilt angle θ1 differs for each of the multiple regions A0 (regions A01 to A07) into which the second incident light LT2A and LT2G are incident on the first surface 11. Furthermore, the direction in which the light totally reflected by the reflective surface 30 is incident on the second surface 12 is not limited to perpendicular; the light totally reflected by the reflective surface 30 may be incident on the second surface 12 at an oblique angle.

[0071] In this embodiment, as shown in Figures 8A and 8B, the multiple prisms 3 are arranged in a zigzag pattern on the first surface 11 when viewed from one side in the Z-axis direction. Here, Figure 8A is a schematic plan view that is an enlarged view of region A1 in Figure 7C. Here, region A1 is a part of region A01 into which the second incident light LT2A, which is parallel light incident perpendicular to the incident surface 10, is incident. Figure 8B is a schematic drawing showing the end face of the line B1-B1 in Figure 8A. Although only a part of the first surface 11 is shown in Figure 8A, in reality, the multiple prisms 3 are formed over almost the entire surface 11.

[0072] Specifically, each prism 3 has a length in the X-axis direction, and multiple prisms 3 are arranged in a row with spacing between them in the longitudinal direction (X-axis direction). Furthermore, multiple prisms 3 are also arranged with spacing between them in the Y-axis direction. When the rows of multiple prisms arranged in the X-axis direction are counted from the incident surface 10 side in the Y-axis direction as the 1st row, 2nd row, 3rd row, etc., the multiple prisms 3 in the even-numbered rows and the multiple prisms 3 in the odd-numbered rows are offset from each other in the X-axis direction. In this embodiment, the multiple prisms 3 in the even-numbered rows and the multiple prisms 3 in the odd-numbered rows are arranged such that their respective longitudinal ends (in the X-axis direction) overlap, for example, in the Y-axis direction. With this arrangement, when viewed from the incident surface 10, the multiple prisms 3 are arranged without gaps in the X-axis direction, and the second incident light LT2 that enters the interior of the light guide member 1 from the incident surface 10 will be reflected by one of the multiple prisms 3. Furthermore, multiple prisms 3 included in even-numbered rows may be arranged such that their respective ends in the longitudinal direction (X-axis direction) are tilted differently with respect to the Y-axis direction. Similarly, multiple prisms 3 included in odd-numbered rows may be arranged such that their respective ends in the longitudinal direction (X-axis direction) are tilted differently with respect to the Y-axis direction.

[0073] In this embodiment, as an example, all of the prisms 3 have the same shape. Therefore, as shown in Figure 8B, the inclination angle θ1 of the reflective surface 30 is the same for the multiple prisms 3 arranged in the Y-axis direction. Furthermore, the dimensions of the prisms 3, such as the longitudinal dimension of the prism 3 and the depth of the recess as a prism 3 (in other words, the height of the prism 3), are also the same for all of the multiple prisms 3. That is, in this embodiment, the prisms 3 are arranged in a multiple-pronged configuration in the Y-axis direction. Here, in each of the regions A01 to A07, the multiple prisms 3 have the same shape. Therefore, if the incidence angle θ0 of the second incident light LT2 incident on the reflective surface 30 in the same region A0 is constant, the direction of the second incident light LT2 reflected by the reflective surface 30 of the prism 3 will be the same regardless of which of the multiple prisms 3 the light is incident on. Consequently, it is possible to cause all of the second incident light LT2 reflected by the multiple prisms 3 in the same region A0 to be incident in a direction perpendicular to the second surface 12.

[0074] Furthermore, as an example, the depth of the recess as prism 3 (in other words, the height of prism 3) is between 1 μm and 100 μm. Similarly, as an example, the pitch of multiple prisms 3 in the Y-axis direction is between 1 μm and 1000 μm. Specifically, the depth of the recess as prism 3 in region A01 is several tens of μm, and the pitch of multiple prisms 3 in the Y-axis direction is several hundred μm.

[0075] The light emission principle of the optical system 100 of this embodiment will be explained below with reference to Figures 1A, 3A, and 3B.

[0076] As shown in Figure 1A, for example, the first incident light LT1A emitted from the light source 4A has its divergence angle controlled as it passes through the light control unit 2A. Then, the second incident light LT2A, with its divergence angle controlled, is emitted from the light control unit 2A toward the incident surface 10 of the light guide member 1. In this embodiment, the second incident light LT2A emitted from the light control unit 2A becomes parallel light parallel to the second surface 12 and is incident perpendicular to the incident surface 10.

[0077] Next, as shown in Figure 1B, most of the second incident light LT2A incident on the incident surface 10 is totally reflected by the reflective surface 30 of one of the prisms 3 provided on the first surface 11, without being reflected by the first surface 11 and the second surface 12. In other words, the light guide member 1 includes a direct optical path L1 that directly reflects the second incident light LT2A incident on the incident surface 10 by the prism 3 and emits it from the second surface 12. Furthermore, in this embodiment, the direct optical path L1 includes the optical path of the second incident light LT2A that undergoes total internal reflection by the prism 3. The second incident light LT2A that undergoes total internal reflection by the reflective surface 30 of the prism 3 follows an optical path perpendicular to the second surface 12 and is emitted from the second surface 12.

[0078] Similarly, as shown in Figures 3A and 3B, the first incident light LT1B and LT1G emitted from light sources 4B and 4G respectively pass through the optical control units 2B and 2G, respectively, and are incident on the incident surface 10 as parallel light, the second incident light LT2B and LT2G. Here, the second incident light LT2B and LT2G become parallel light that intersects with the second incident light LT2A. Also, the second incident light LT2B and LT2G become parallel light that intersects each other. In other words, the directions of the optical axes P2A and P2G of the second incident light LT2A and LT2G are different from each other. Furthermore, the directions of optical axes P2A to P2G are not limited to being different from each other; if at least two of the optical axes P2 among optical axes P2A to P2G are in different directions, there may be optical axes P2 among optical axes P2A to P2G that are in the same direction.

[0079] Then, as shown in Figure 3B, the second incident light LT2B to LT2G, which are totally reflected by the reflective surface 30 of one of the multiple prisms 3 provided on the first surface 11, follow an optical path perpendicular to the second surface 12 and are emitted from the second surface 12.

[0080] In this embodiment, since multiple prisms 3 are arranged across the entire surface 11, the second incident light LT2A to LT2G are emitted as light from the second surface 12 of the light guide member 1 through the direct optical path L1 described above. As a result, the second surface 12 emits surface light, and the emitted light becomes planar light. In this embodiment, since the directions of the optical axes P2A to P2G are different, the brightness distribution of the second incident light LT2 incident on the first surface 11 is non-uniform. Furthermore, since the second incident light LT2 incident on the first surface 11 follows the direct optical path L1 and is emitted perpendicular to the second surface 12, the brightness distribution of the emitted light on the second surface 12 is non-uniform. In other words, by controlling the directions of the optical axes P2A to P2G of the second incident light LT2A to LT2G using the optical control units 2A to 2G, it is possible to obtain emitted light with a desired brightness distribution on the second surface 12.

[0081] The advantages of the optical system 100 of this embodiment, which includes optical control units 2A to 2G, will be described below with reference to Figures 3A to 3B and Figures 9 to 10.

[0082] In a typical optical system (hereinafter referred to as the comparative optical system 100A), the direction of the optical axis P2 of each of the multiple second incident light beams LT2 incident on the incident surface 10 from the multiple light control bodies (hereinafter referred to as the multiple light control bodies of the comparative example) is equal to that of the other. Figure 9 shows the luminance distribution of the emitted light in the comparative optical system 100A. In the comparative optical system 100A, the multiple second incident light beams LT2 incident on the incident surface 10 from the multiple light control bodies are parallel light beams that are parallel to each other and incident perpendicular to the incident surface 10. In this case, the luminance distribution of the second incident light beams LT2 incident on the first surface 11 from the incident surface 10 is uniform. Then, the second incident light beams LT2 incident on the first surface 11 follow the direct optical path L1 and are emitted perpendicular to the second surface 12, so the luminance distribution AR1 of the emitted light on the second surface 12 is uniform as shown in Figure 9. The luminance distributions AR1 and AR2 shown in Figures 9 and 10, respectively, schematically represent the luminance distribution on the second surface 12 of the emitted light. Here, luminance distributions AR1 and AR2 indicate regions where the amount of emitted light is relatively higher than outside the ranges of luminance distributions AR1 and AR2.

[0083] When an optical system 100 including a plurality of light control units 2 is applied to a head-up display mounted on a mobile body B1, as in the display system 300 according to this embodiment, it is required that the brightness distribution on the second surface 12 of the emitted light be controlled unevenly for the plurality of light control units 2 for the following reasons.

[0084] The display surface 312 of the image display unit 310 of the head-up display receives emitted light from the second surface 12 via the light distribution control unit 14, which will be described later, and displays an image. The display surface 312 has a shape (for example, rectangular) that matches the range of the image projected onto the user U1, that is, the shape of the windshield B12. The second surface 12 is also provided with a shape that matches the display surface 312.

[0085] Here, the image displayed on the display surface 312 has a luminance distribution that changes before it is reflected by the windshield B12 and seen by the user U1. Therefore, it is necessary to pre-apply a luminance distribution to the emitted light that functions as the backlight of the display surface 312 so that it produces an optimal image when seen by the user U1.

[0086] For example, in this embodiment, the image displayed on the rectangular display surface 312 shows a decrease in the intensity of light from the upper left of the windshield B12 as seen by the user U1 by the time the user U1 sees it. This is partly because the length of the optical path between the display surface 312 and the user U1's eye box C1 is longer in the upper left region of the windshield B12, causing the light to scatter more strongly.

[0087] Therefore, in this embodiment, by controlling the directions of the optical axes P2A to P2G using the optical control units 2A to 2G respectively, the luminance distribution AR2 on the second surface 12 of the emitted light emitted from the emission surface (second surface 12) is controlled so that the lower right is relatively brighter and the upper left is darker, as shown in Figure 10. In this embodiment, the vertical direction of the windshield B12 as seen by the user U1 corresponds to the X-axis direction in Figures 9 and 10 with the top and bottom reversed, and the left and right direction of the windshield B12 as seen by the user U1 corresponds to the Y-axis direction with the left and right reversed. Therefore, by controlling the luminance distribution AR2 on the second surface 12 so that the lower right is relatively brighter and the upper left is darker, the decrease in light intensity in the upper left of the windshield B12 is corrected, and an image with uniform brightness can be viewed by the user U1.

[0088] In this embodiment, in order to obtain the luminance distribution AR2 shown in Figure 10, the directions of optical axes P2A to P2G are controlled such that the inclination of optical axes P2B to P2G with respect to optical axis P2A increases along the X-axis direction from light source 4A to light source 4G, as shown in Figure 3A. Also, as shown in Figure 3B, the directions of optical axes P2A to P2G are controlled such that, when viewed from the X-axis direction, the inclination of optical axes P2B to P2F with respect to optical axis P2A is equal, and the inclination of optical axis P2G with respect to optical axis P2A is greater than the inclination of optical axes P2B to P2F with respect to optical axis P2A. Note that the directions of optical axes P2A to P2G can be appropriately changed according to the desired luminance distribution AR2.

[0089] (2.4) Light control unit Next, the shape and function of the optical control unit 2 according to this embodiment will be described in detail with reference to Figures 2 and 11 to 13.

[0090] The optical control unit 2 is equipped with an incident lens 21. In this embodiment, the incident lens 21 of optical control units 2B to 2G includes a plurality of lens sections 22, each having different lens characteristics, such as the distribution of curvature on the lens. This allows optical control units 2B to 2G to change the direction of the optical axis P2 from the direction of the optical axis P1.

[0091] In an incident lens 21 provided by the optical control unit 2A, where the curvature distribution on the lens is, for example, rotationally symmetric with respect to the central axis of the lens, when a first incident light LT1 having an optical axis P1 that coincides with the normal L21 of the main incident surface 211 is incident, the direction of the optical axis P2 of the second incident light LT2 will be the same as the direction of the optical axis P1. Note that the incident lens 21 provided by the optical control unit 2A does not need to be rotationally symmetric with respect to the central axis of the lens, as long as the direction of the optical axis P2 can be controlled to be the same as the direction of the optical axis P1.

[0092] On the other hand, each of the optical control units 2B to 2G has different curvature distributions in each of its multiple lens sections 22, thereby allowing a second incident light LT2, which is parallel light with an optical axis P2 different from the direction of the optical axis P1, to be incident on the incident surface 10.

[0093] As shown in Figure 11, in this embodiment, for example, the incident lens 21 of the light control units 2B to 2G has four lens sections 22 (first lens section 221 to fourth lens section 224). The light control units 2B to 2G each direct the first incident light LT1, which is incident from the light source 4 onto the first lens section 221 to the fourth lens section 224, onto the incident surface 10.

[0094] Here, the area of ​​each of the first lens section 221 to the fourth lens section 224, as viewed from the direction of the optical axis P1 of the first incident light LT1, is equal. Furthermore, each of the first lens section 221 to the fourth lens section 224 is arranged in a fan shape that extends outward from the point Q1 where the incident lens 21 intersects the optical axis P1. The first lens section 221 and the third lens section 223, which are installed opposite each other in the radial direction of a circle centered on point Q1, are, for example, point symmetric with respect to point Q1 when viewed from the direction of the optical axis P1. Similarly, the second lens section 222 and the fourth lens section 224, which are installed opposite each other in the radial direction of a circle centered on point Q1, are, for example, point symmetric with respect to point Q1 when viewed from the direction of the optical axis P1. In other words, the incident lens 21 is equally divided into the first lens section 221 to the fourth lens section 224 by a plurality (two in this embodiment) of planes PL2 and PL3 that intersect each other. In this embodiment, the straight line formed by the two intersecting planes PL2 and PL3 coincides with the optical axis P1. Furthermore, the first lens portion 221 and the third lens portion 223 do not need to be point-symmetric with respect to point Q1, as long as their areas viewed from the direction of the optical axis P1 are equal. Similarly, the second lens portion 222 and the fourth lens portion 224 do not need to be point-symmetric with respect to point Q1, as long as their areas viewed from the direction of the optical axis P1 are equal.

[0095] Furthermore, the first lens section 221 to the fourth lens section 224 are smoothly continuous. In other words, the curvature of the incident lens 21 is greater than 0 at each boundary between the first lens section 221 to the fourth lens section 224.

[0096] Incidentally, as shown in Figure 2, the incident lens 21 comprises a refractive lens 23 and a reflective lens 24. In this embodiment, the refractive lens 23 is formed to be circular when viewed from the direction of the optical axis P1. The reflective lens 24 is formed in an annular shape that surrounds the outer circumference of the circular refractive lens 23 over its entire circumference.

[0097] The refractive lens 23 has a main incident surface 211. The main incident surface 211 is positioned opposite the light source 4, and at least a portion of the first incident light LT1 from the light source 4 enters the refractive lens 23 from the main incident surface 211. Here, since the first incident light LT1 is light that spreads radially from the light source 4, at least a portion of the first incident light LT1 entering the refractive lens 23 is refracted at the main incident surface 211 according to the angle of incidence of the light ray with respect to the main incident surface 211. At least a portion of the first incident light LT1 refracted at the main incident surface 211 enters the incident surface 10 as at least a portion of the second incident light LT2, which is parallel light.

[0098] The reflective lens 24 has a secondary incident surface 212 and an outer peripheral surface 213.

[0099] The secondary incident surface 212 is directed toward the normal L21 of the main incident surface 211. In this embodiment, the secondary incident surface 212 is provided in an annular shape surrounding the main incident surface 211. However, the secondary incident surface 212 is not limited to an annular shape surrounding the main incident surface 211, and may be located in at least a part of the periphery of the main incident surface 211. Furthermore, the secondary incident surface 212 may be parallel to (i.e., not inclined) or inclined with respect to the normal L21 of the main incident surface 211.

[0100] The outer peripheral surface 213 is located on the opposite side from the normal L21 of the main incident surface 211 when viewed from the sub-incident surface 212.

[0101] At least a portion of the first incident light LT1 enters the reflective lens 24 from the sub-incidence surface 212. At least a portion of the first incident light LT1 entering the reflective lens 24 is refracted at the sub-incidence surface 212 according to the angle of incidence of the light ray with respect to the sub-incidence surface 212. At least a portion of the first incident light LT1 refracted at the sub-incidence surface 212 is totally reflected by the outer circumferential surface 213 and enters the incident surface 10 as at least a portion of the second incident light LT2.

[0102] For example, as shown in Figure 12, in the case of an optical control unit 2A that controls the first incident light LT1 so that the optical axis P2 is on the optical axis P1, at least a portion of the first incident light LT1A refracted at the main incident surface 211 is incident perpendicular to the incident surface 10 as at least a portion of the second incident light LT2A, which is parallel light. Also, at least a portion of the first incident light LT1A refracted at the secondary incident surface 212 is totally reflected by the outer peripheral surface 213 and incident perpendicular to the incident surface 10 as at least a portion of the second incident light LT2A.

[0103] Furthermore, as shown in Figure 13, for example, in the case of an optical control unit 2G that controls the first incident light LT1 so that the optical axes P1 and P2 intersect (form an angle of 0 degrees or more), at least a portion of the first incident light LT1G refracted at the main incident surface 211 is incident on the incident surface 10 at an angle as at least a portion of the second incident light LT2G, which is parallel light. Also, at least a portion of the first incident light LT1G refracted at the secondary incident surface 212 is totally reflected by the outer peripheral surface 213 and incident on the incident surface 10 at an angle as at least a portion of the second incident light LT2G. Here, at least a portion of the first incident light LT1G is refracted in the same direction, for example, regardless of its position on the main incident surface 211 of the optical control unit 2G. Also, at least a portion of the first incident light LT1G is reflected in the same direction, for example, regardless of its position on the outer peripheral surface 213. Furthermore, the direction in which at least a portion of the first incident light LT1G is refracted at the main incident surface 211 and the direction in which it is reflected at the outer peripheral portion 213 are, for example, the same direction. The lens portion 21 may be configured such that at least a portion of the first incident light LT1G is refracted in different directions depending on its position on the main incident surface 211, or at least a portion of the first incident light LT1G is reflected in different directions depending on its position on the outer peripheral surface 213. The lens portion 21 may also be configured such that the direction in which at least a portion of the first incident light LT1G is refracted at the main incident surface 211 and the direction in which it is reflected at the outer peripheral portion 213 are different.

[0104] Here, as described above, the incident lens 21 possessed by the optical control units 2B to 2G includes the first lens section 221 to the fourth lens section 224. Also as described above, the incident lens 21 comprises a refractive lens 23 and a reflective lens 24 (see Figure 2). The refractive lens 23 is formed to be circular, for example, when viewed from the direction of the optical axis P1. The reflective lens 24 is formed in an annular shape, for example, surrounding the outer circumference of the circular refractive lens 23 over its entire circumference. Therefore, as shown in Figure 11, each of the first lens section 221 to the fourth lens section 224 includes, for example, a refractive lens section (first refractive lens section 231 to fourth refractive lens section 234) which is part of the circular refractive lens 23, and a reflective lens section (first reflective lens section 241 to fourth reflective lens section 244) which is part of the annular reflective lens 24 that surrounds the outer circumference of the refractive lens 23. Furthermore, each of the first refractive lens sections 231 to the fourth refractive lens section 234 has a first main incident surface 2111 to the fourth main incident surface 2114, which is part of the main incident surface 211. Each of the first reflective lens sections 241 to the fourth reflective lens section 244 has a first sub-incident surface 2121 to the fourth sub-incident surface 2124, which is part of the sub-incident surface 212, and a first outer peripheral surface 2131 to the fourth outer peripheral surface 2134, which is part of the outer peripheral surface 213.

[0105] At least a portion of the first incident light LT1 that enters each of the first refractive lens sections 231 to 234 from each of the first main incident surfaces 2111 to 2114 is refracted at each of the first main incident surfaces 2111 to 2114. At least a portion of the first incident light LT1 that has been refracted at each of the first main incident surfaces 2111 to 2114 enters the incident surface 10 as at least a portion of the second incident light LT2, which is parallel light.

[0106] Furthermore, at least a portion of the first incident light LT1 that enters each of the first reflective lens sections 241 to 244 from each of the first sub-incidence surfaces 2121 to 2124 is refracted at each of the first sub-incidence surfaces 2121 to 244. At least a portion of the first incident light LT1 that has been refracted at each of the first sub-incidence surfaces 2121 to 2124 is totally reflected by each of the first outer peripheral surfaces 2131 to 4 outer peripheral surfaces 2134 and enters the incident surface 10 as at least a portion of the second incident light LT2.

[0107] In other words, at least a portion of the first incident light LT1 that enters the first lens section 221 to the fourth lens section 224 becomes the second incident light LT21 to the second incident light LT24, which are at least a portion of the second incident light LT2, and enters the incident surface 10 from each of the first lens section 221 to the fourth lens section 224.

[0108] Here, each of the second incident light beams LT21 to LT24 is, for example, parallel light. Also, the optical axes of each of the second incident light beams LT21 to LT24 are, for example, parallel to each other. In other words, the second incident light beam LT2 that each of the light control units 2B to 2G incidents onto the incident surface 10 includes, for example, the parallel second incident light beams LT21 to LT24.

[0109] (2.5) Light distribution control unit Next, the light distribution control unit 14 will be described in detail with reference to Figure 4.

[0110] In this embodiment, at least one of the first surface 11 and the second surface 12 has a light distribution control unit 14. The light distribution control unit 14 controls the light distribution of the emitted light taken out from the second surface 12, which is the emission surface. Here, "light distribution of emitted light" refers to the spread of the emitted light. In this embodiment, as an example, the light distribution control unit 14 is provided on the second surface 12. Furthermore, in this embodiment, the light distribution control unit 14 is integrated with the light guide member 1 as an integrally molded product. In other words, in this embodiment, the light guide member 1 and the light distribution control unit 14 are integrally molded products and are inseparable.

[0111] In short, in this embodiment, the light guide member 1 includes a direct optical path L1 that causes the second incident light LT2, which enters the light guide member 1 from the incident surface 10, to exit from the second surface 12 after only one reflection by the prism 3 inside the light guide member 1. Therefore, the shapes of the first surface 11 and the second surface 12 do not contribute to the guidance of the second incident light LT2 inside the light guide member 1, and even if a light distribution control unit 14 is provided on the first surface 11 or the second surface 12, the light guidance performance of the light guide member 1 is unlikely to deteriorate.

[0112] Specifically, the light distribution control unit 14 in this embodiment includes a lens. In other words, the light distribution control unit 14 has the function of a lens as an optical element for refracting, diverging, or focusing light. As a result, the light distribution control unit 14 can control the light distribution by refracting, diverging, or focusing the emitted light taken out from the second surface 12, which is the emission surface.

[0113] More specifically, the light distribution control unit 14 includes a multi-lens system consisting of a group of multiple small lenses 141. In this embodiment, each of the multiple small lenses 141 is formed in a semi-cylindrical shape. These multiple small lenses 141 are arranged in a line along the X-axis. Here, the multiple small lenses 141 are formed without gaps across the entire area of ​​the second surface 12. A multi-lens system consisting of a group of multiple small lenses 141 of this shape constitutes a so-called cylindrical lens.

[0114] For example, in this embodiment, the light distribution control unit 14 maintains the relative brightness distribution on the second surface 12 of the emitted light and controls the light distribution of the emitted light so that the emitted light is projected onto the display surface 312 of the image display unit 310 with an appropriate size.

[0115] (3) Variant Modifications of the above embodiment will be described below. However, components common to the above embodiment will be given the same reference numerals, and their descriptions will be omitted as appropriate. Furthermore, each of the modifications described below can be applied in appropriate combination with each of the components described in the above embodiment.

[0116] (3.1) Variation 1 In the optical system 100 of the above embodiment, the refractive lens 23 is formed to be circular when viewed from the direction of the optical axis P1. The reflective lens 24 is formed to surround the entire circumference of the circular refractive lens 23. On the other hand, the optical system 100 of Modification 1 differs from the above embodiment in that, as shown in Figure 14, the refractive lens 23 is formed to be a circular shape with a portion missing (partially circular) when viewed from the direction of the optical axis P1. The refractive lens 23 of Modification 1 includes an arc portion 235 and a chord portion 236 on its partial circular outer circumference, and the reflective lens 24 is formed along the arc portion 235 of the refractive lens 23.

[0117] In this case, among the refractive lenses 23A to 23G provided by each of the optical control units 2A to 2G, the refractive lenses 23 adjacent to each other in the X-axis direction share a common chord 236 and are continuous at the common chord 236.

[0118] (3.2) Variation 2 In the optical system 100 of the above embodiment, the optical axes of the second incident light LT21 to the second incident light LT24 are parallel to each other. On the other hand, the optical system 100 of Modified Example 2 differs from the above embodiment in that at least two of the optical axes of the second incident light LT21 to the second incident light LT24 are in different directions. In other words, the optical control body 2 of Modified Example 2 can separately control the emission directions of the parallel light second incident light LT21 to the second incident light LT24. This allows for more precise control of the brightness distribution of the emitted light on the second surface 12 compared to the case in the above embodiment where the emission direction of the second incident light LT2 is controlled for each of the multiple optical control bodies 2.

[0119] (3.3) Other variations The first refractive lens sections 231 to the fourth refractive lens sections 234 and the first reflective lens sections 241 to the fourth reflective lens sections 244 may each independently control the direction of refraction of the first incident light LT1 incident on each of them, and the directions of refraction of the first incident light LT1 incident on each of the first refractive lens sections 231 to the fourth refractive lens sections 234 and the first reflective lens sections 241 to the fourth reflective lens sections 244 do not all have to be the same.

[0120] The first surface 11 may be a surface perpendicular to the incident surface 10, and the second surface 12 may be a surface that is not perpendicular to the incident surface 10 but is inclined with respect to the XY plane. Alternatively, both the first surface 11 and the second surface 12 may be surfaces that are not perpendicular to the incident surface 10 but are inclined with respect to the XY plane.

[0121] The light guide member 1 only needs to include a direct optical path L1, and it is not essential that all of the second incident light LT2 incident from the incident surface 10 passes through the direct optical path L1. In other words, the light guide member 1 may include, for example, an indirect optical path that reflects once or more times on the first surface 11 or the second surface 12, and then reflects off the prism 3 to exit from the second surface 12.

[0122] Furthermore, the first surface 11 may be provided with only one prism 3 instead of multiple prisms 3. In this case, the prism 3 may be formed across the entire surface of the first surface 11 and may have multiple reflective surfaces 30 with different inclination angles.

[0123] In Embodiment 1, the prism 3 is formed by processing the first surface 11 of the light guide member 1, but the embodiment is not limited to this. For example, the prism 3 may be provided on the first surface 11 by attaching a prism sheet on which the prism 3 is formed to the first surface 11. In this case, the prism sheet may have one prism 3 or multiple prisms 3 formed on it.

[0124] The prism 3 is not limited to a concave shape relative to the first surface 11, that is, a shape recessed from the first surface 11, but may also be convex, that is, a shape protruding from the first surface 11.

[0125] The end face 13 of the light guide member 1 may be an inclined surface that is tilted with respect 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. Because the end face 13 is such an inclined surface, even if a portion of the second incident light LT2 incident from the incident surface 10 reaches the end face 13 without being incident on the first surface 11, it is possible to emit this portion of the second incident light LT2 from the second surface 12. That is, when a portion of the second incident light LT2 incident from the incident surface 10 is incident on the end face 13, a portion of the second incident light LT2 is totally reflected at the end face 13 toward the second surface 12 and emitted from the second surface 12. As a result, in addition to the light emitted out of the light guide member 1 from the second surface 12 through the direct optical path L1, even a portion of the second incident light LT2 that reached the end face 13 can be effectively extracted from the second surface 12.

[0126] The light distribution control unit 14 only needs to control the light distribution of the light extracted from the second surface 12, and only needs to be provided on at least one of the first surface 11 and the second surface 12. That is, in the above embodiment, the light distribution control unit 14 is provided on the second surface 12 as the emission surface, but the configuration is not limited to this, and the light distribution control unit 14 may be provided on the first surface 11, or on both the first surface 11 and the second surface 12. Furthermore, in the above embodiment, the light distribution control unit 14 is integrated with the light guide member 1 as an integrally molded product, but the configuration is not limited to this. For example, the light distribution control unit 14 may be provided on the second surface 12 by attaching a light distribution sheet on which the light distribution control unit 14 is formed to the second surface 12.

[0127] The light distribution control unit 14 is not limited to a lens; for example, it may be a diffusion sheet, a prism, or a diffraction grating. Furthermore, the light distribution control unit 14 is not an essential component of the optical system 100 and can be omitted as appropriate.

[0128] The mobile body B1 on which the display system 300 is installed is not limited to automobiles (passenger cars), but may also be, for example, large vehicles such as trucks or buses, motorcycles, trains, electric carts, construction machinery, aircraft, or ships.

[0129] The display system 300 is not limited to a configuration that displays a virtual image, such as a head-up display. For example, the display system 300 may be a liquid crystal display or a projector device. Alternatively, the display system 300 may be a display unit of a car navigation system, electronic mirror system, or multi-information display mounted on the mobile body B11.

[0130] The lighting system 200 is not limited to the configuration used in the display system 300, but may also be used for industrial applications such as resin curing or plant cultivation, or for lighting applications including emergency lights.

[0131] (4) Summary As described above, the optical system (100) according to the first embodiment comprises a light guide member (1), a prism (3), and a plurality of light control units (2). The light guide member (1) has an incident surface (10) into which light is incident, and a first surface (11) and a second surface (12) that face each other. The second surface (12) of the light guide member (1) is the light exit surface. The prism (3) is provided on the first surface (11) and reflects the light passing through the inside of the light guide member (1) toward the second surface (12). The plurality of light control units (2) are located between the light source (4) and the incident surface (10). The plurality of light control units (2) control the light output from the light source (4) that is incident on the incident surface (10). Each of the plurality of light control units (2) is equipped with an incident lens (21). Each of the multiple light control units (2) directs the light incident from the light source (4) to the incident lens (21) onto the incident surface (10). At least two of the multiple light control units (2) direct the light incident on the incident surface (10) in directions of the optical axes of each unit that are different from each other.

[0132] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled by controlling the optical axis of the light incident on the incident surface (10) for each of the multiple light control units (2).

[0133] In the optical system (100) according to the second embodiment, in the first embodiment, the angle formed by the optical axes of the light incident on the incident surface (10) by each of the two optical control bodies (2) is greater than 0 degrees and 15 degrees or less.

[0134] According to this embodiment, the luminance distribution of the light emitted from the second surface (12) can be controlled within an appropriate range on the second surface (12).

[0135] In the optical system (100) according to the third embodiment, in the first or second embodiment, the incident lens (21) includes a plurality of lens sections (22) with different lens characteristics. Each of the plurality of optical control units (2) causes the light incident from the light source (4) on each of the plurality of lens sections (22) to be incident on the incident surface (10). At least two of the plurality of lens sections (22) have different directions for the optical axes of the light incident on the incident surface (10).

[0136] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled more precisely.

[0137] In the optical system (100) according to the fourth embodiment, in the third embodiment, the incident lens (21) is equally divided into a plurality of lens portions (22) by a plurality of planes that intersect each other.

[0138] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled more precisely.

[0139] In the optical system (100) according to the fifth embodiment, in the third or fourth embodiment, each of the multiple lens sections (22) is smoothly continuous.

[0140] According to this embodiment, the light incident from the light source (4) on the multiple lens parts (22) can be effectively incident on the incident surface (10).

[0141] In the optical system (100) according to the sixth embodiment, in any of the third to fifth embodiments, the incident lens (21) has four lens sections (22).

[0142] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled more precisely.

[0143] In the optical system (100) according to the seventh embodiment, in any of the third to sixth embodiments, the plurality of lens portions (22) include refractive lens portions that refract light and reflective lens portions that reflect light.

[0144] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled more precisely.

[0145] In the optical system (100) according to the eighth embodiment, in any of the first to seventh embodiments, the light guide member (1) includes a direct optical path (L1) that directs light incident from the incident surface (10) to the second surface (12) by the prism (3).

[0146] According to this embodiment, it is possible to improve the efficiency of light intake.

[0147] The ninth aspect of the illumination system (200) comprises an optical system (100) according to any of the first to eighth aspects, and a light source (4) that outputs light incident on the incident surface (10).

[0148] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled.

[0149] The display system (300) according to the tenth embodiment comprises a lighting system (200) according to the ninth embodiment and a display unit (5) that receives light emitted from the lighting system (200) and displays an image.

[0150] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled.

[0151] The mobile body (B1) according to the 11th embodiment comprises a display system (300) according to the 10th embodiment and a mobile body (B11) on which the display system (300) is mounted.

[0152] According to this embodiment, the brightness distribution of the light emitted from the second surface (12) can be controlled.

[0153] According to this disclosure, there is an advantage in that it can reduce unevenness in the brightness of images viewed by the user. [Explanation of symbols]

[0154] 1. Light guide member 2. Light control unit 3 prisms 4 light source 5 Display 10 Entrance plane 11 Page 1 12 Side 2 21 Incident lens 22 Lens section 100 Optical Systems 200 Lighting Systems 300 Display Systems B1 Mobile Unit B11 Mobile Unit L1 Direct Optical Path

Claims

1. A light guide member having an incident surface into which light is incident, and a first surface and a second surface facing each other, wherein the second surface is the light emission surface, A prism provided on the first surface reflects light passing through the inside of the light guide member toward the second surface, The system comprises a plurality of light control units positioned between the light source and the incident surface, which control the light output from the light source and incident on the incident surface, Each of the aforementioned plurality of light control units is equipped with an incident lens, Each of the plurality of light control units causes the light incident on the incident lens from the light source to be incident on the incident surface. Of the plurality of light control units, at least two of the light control units have different directions for the optical axis of the light incident on the incident surface. The incident lens includes a plurality of lens sections with different curvature distributions from each other. Each of the plurality of light control units causes the light incident from the light source to each of the plurality of lens sections to be incident on the incident surface, At least two of the aforementioned plurality of lens portions have different optical axis directions for the light that each lens portion directs into the incident surface. Optical system.

2. The angle formed by the optical axes of the light incident on the incident surface by each of the at least two light control units is greater than 0 degrees and less than or equal to 15 degrees. The optical system according to claim 1.

3. The incident lens is divided into a plurality of lens portions equally by a plurality of planes that intersect each other. The optical system according to claim 1 or 2.

4. Each of the plurality of lens portions is smoothly continuous. The optical system according to any one of claims 1 to 3.

5. The incident lens has four lens portions The optical system according to any one of claims 1 to 4.

6. The plurality of lens portions include a refractive lens portion that refracts light and a reflective lens portion that reflects light. The optical system according to any one of claims 1 to 5.

7. The light guide member includes a direct optical path that causes light incident from the incident surface to be directly reflected by the prism and emitted from the second surface. The optical system according to any one of claims 1 to 6.

8. The optical system according to any one of claims 1 to 7, The system includes a light source that outputs light incident on the incident surface. Lighting system.

9. The lighting system according to claim 8, The system includes a display unit that receives light emitted from the aforementioned lighting system and displays an image. Display system.

10. The display system according to claim 9, A mobile body equipped with the aforementioned display system, A mobile object.

Images