JP7390546B2 - Optical systems, lighting systems, display systems and moving objects - Google Patents

Description

TECHNICAL FIELD The present disclosure generally relates to optical systems, illumination systems, display systems, and moving objects. More specifically, the present disclosure relates to an optical system, an illumination system, a display system, and a moving object that control light that has entered from an incident surface and causes it to exit from an exit surface.

Patent Document 1 discloses an image display device (display system) that projects a virtual image onto a target space. This image display device is an automotive HUD (Head-Up Display) device. Projected light, which is image light, emitted from an automobile HUD device (optical system) in the dashboard is reflected by the windshield and directed toward the driver, who is the viewer. Thereby, the user (driver) can visually recognize an image such as a navigation image as a virtual image, and visually recognize the virtual image as if it were superimposed on a background such as a road surface.

Japanese Patent Application Publication No. 2017-142491

An object of the present disclosure is to provide an optical system, a lighting system, a display system, and a moving object that can improve light extraction efficiency.

An optical system according to one aspect of the present disclosure includes a light guide member, a prism, and a light control body. The light guide member has an entrance surface on which light from a light source enters, and a first surface and a second surface that face each other. The second surface of the light guide member is a light exit surface. The prism is provided on the first surface and reflects light passing through the light guide member toward the second surface. The light controller is located between a light source and the incident surface, and controls light output from the light source and incident on the incident surface. The light guide member includes a direct optical path that directly reflects the light incident from the incident surface on the prism and outputs it from the second surface. The optical axis of the light incident from the incident surface is inclined with respect to the first surface such that the distance to the first surface decreases as the distance from the incident surface increases. The light control body is integrated with the light guide member. The light control body includes a path generating section that extends along a straight line that is inclined with respect to the first surface when viewed from the incident surface, and forms a light path between the light source and the incident surface. . The light control body includes an entrance lens. The optical axis of the light source is inclined toward the first surface with respect to the optical axis of the incident surface. The entrance lens has a main entrance surface and a sub-incident surface. The main entrance surface is arranged to face the main entrance surface and the light source. The sub-incidence surface is located on at least a portion of the periphery of the main entrance surface, and is oriented toward a normal to the main entrance surface. The entrance lens has the sub-incidence surface on the first surface side, and is open on the second surface side.

An illumination system according to one aspect of the present disclosure includes the optical system and a light source that outputs light that is incident on the incident surface.

A display system according to one aspect of the present disclosure includes the illumination system, and a display that receives light emitted from the illumination system and displays an image.

A moving object according to an aspect of the present disclosure includes the display system and a moving object main body on which the display system is mounted.

According to the present disclosure, there is an advantage that light extraction efficiency can be improved.

FIG. 1A is a cross-sectional view schematically showing an optical system according to the first embodiment. FIG. 1B is an enlarged schematic diagram of region A1 in FIG. 1A. FIG. 2 is a conceptual diagram showing an outline of the light control body of the optical system. FIG. 3 is a perspective view showing an outline of the optical system as described above. FIG. 4 is an explanatory diagram of a display system using the same optical system. FIG. 5 is an explanatory diagram of a mobile body equipped with the display system as described above. FIG. 6A is a plan view of the above optical system. FIG. 6B is a front view of the optical system same as above. FIG. 6C is a bottom view of the above optical system. FIG. 6D is a side view of the same optical system. FIG. 7A is an enlarged schematic diagram of region A1 in FIG. 6C. FIG. 7B is a sectional view taken along the line B1-B1 in FIG. 7A. FIG. 8A is a perspective view showing the shape of the light control body same as above. FIG. 8B is a sectional view taken along the line B1-B1 in FIG. 8A. FIG. 8C is a sectional view taken along the line C1-C1 in FIG. 8A. FIG. 9A is an explanatory diagram showing the light intensity distribution of the light control body same as above. FIG. 9B is an explanatory diagram showing the light intensity distribution of the light control body according to the comparative example. FIG. 10A is an explanatory diagram showing the light intensity distribution of the light controller same as above. FIG. 10B is an explanatory diagram showing the light intensity distribution of the light control body according to the comparative example. FIG. 11A is an explanatory diagram showing the intensity distribution of light when the light guide member is viewed from one side in the thickness direction when light is emitted from the light control body to the light guide member. FIG. 11B is an explanatory diagram showing the intensity distribution of light when the light guide member is viewed from one side in the thickness direction when light is emitted from the light control body according to the comparative example to the light guide member. FIG. 12A is an explanatory diagram schematically showing light rays passing through the inside of the light control body same as above. FIG. 12B is an explanatory diagram schematically showing light rays passing through the inside of the light control body according to the comparative example. FIG. 12C is an explanatory diagram schematically showing light rays passing through the inside of a light control body according to another comparative example. FIG. 13A is a side view schematically showing an optical system according to a first modification. FIG. 13B is an enlarged schematic diagram of region A1 in FIG. 13A. FIG. 13C is an enlarged schematic diagram of area A2 in FIG. 13A. FIG. 14A is a side view schematically showing an optical system according to a second modification. FIG. 14B is a cross-sectional view showing an outline of the above optical system. FIG. 15 is a front view schematically showing a light control body according to a third modification. FIG. 16A is an explanatory diagram of an illumination system using an optical system according to a fourth modification. FIG. 16B is an enlarged schematic diagram of region A1 in FIG. 16A. FIG. 17A is a plan view of essential parts of an example of an optical system according to a fifth modification. FIG. 17B is a plan view of main parts showing another example of the optical system according to the fifth modification. FIG. 18A is a schematic diagram showing an example of a prism according to a sixth modification. FIG. 18B is a schematic diagram showing another example of the prism according to the sixth modification. FIG. 19A is a schematic diagram showing still another example of the prism according to the sixth modification. FIG. 19B is a schematic diagram showing still another example of the prism according to the sixth modification. FIG. 20A is a schematic diagram showing still another example of the prism according to the sixth modification. FIG. 20B is a schematic diagram showing still another example of the prism according to the sixth modification. FIG. 21A is a schematic diagram showing an example of a prism according to a seventh modification. FIG. 21B is a schematic diagram showing another example of the prism according to the seventh modification. FIG. 21C is a schematic diagram showing still another example of the prism according to the seventh modification. FIG. 22A is a bottom view showing an overview of the optical system according to the second embodiment. FIG. 22B is an enlarged schematic diagram of the first region of the optical system. FIG. 22C is an enlarged schematic diagram of the mixed area of the optical system same as above. FIG. 22D is an enlarged schematic diagram of the second region of the optical system.

(Embodiment 1)
(1) Overview First, an overview of an optical system 100 according to the present embodiment and an illumination system 200 using the optical system 100 will be described with reference to FIGS. 1A to 3.

The optical system 100 (see FIGS. 1A and 1B) according to the present embodiment has a function of controlling light that has entered from the entrance surface 10 and outputting it from the exit surface (second surface 12). The optical system 100 includes a light guide member 1, a light control body 2, and a prism 3, as shown in FIGS. 1A and 1B.

Optical system 100 together with light source 4 constitutes 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 that is incident on the entrance surface 10 . As will be described in detail later, when the optical system 100 includes the light controller 2, the light from the light source 4 does not enter the light guide member 1 directly, but enters the light guide member 1 through the light controller 2. do. That is, the light source 4 emits light to the incident surface 10 (of the light guide member 1) through the light controller 2.

In this way, in this embodiment, the optical system 100 further includes the light control body 2 in addition to the light guide member 1 and the prism 3. The light controller 2 is located between the light source 4 and the entrance surface 10 of the light guide member 1, and controls the light output from the light source 4 and incident on the entrance surface 10. In particular, in this embodiment, the light guide member 1 and the light control body 2 are integrated as an integrally molded product. That is, in this embodiment, the light guide member 1 and the light control body 2 are integrally molded and are inseparable from each other. In other words, the light control body 2 is seamlessly continuous with the incident surface 10 of the light guide member 1, and the light guide member 1 and the light control body 2 are seamlessly integrated. Therefore, in the present embodiment, the incident surface 10 of the light guide member 1 is a "virtual surface" defined inside the integrally molded product of the light guide member 1 and the light control body 2, and has no substance.

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

Here, the light guide member 1 includes a direct optical path L1 (see FIGS. 1A and 1B). The direct optical path L1 is an optical path in which light that enters from the entrance surface 10 is directly reflected by the prism 3 and output from the second surface 12. More specifically, the light guide member 1 causes the light that enters the light guide member 1 from the incident surface 10 to exit from the second surface 12 by only one reflection at the prism 3 inside the light guide member 1. It includes an optical path (direct optical path L1). When the light passing through the direct optical path L1 enters the light guide member 1 from the incident surface 10, it is not reflected by anything other than the prism 3, and reaches the second surface 12 with only one reflection from the prism 3, and then directly passes through the second surface 12. The light is emitted from the second surface 12 to the outside of the light guide member 1 .

In this embodiment, most of the light that enters the light guide member 1 from the entrance surface 10 and exits 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 that enters the light guide member 1 from the incident surface 10 is not reflected by anything other than the prism 3, and is reflected only once by the prism 3, and is reflected only once by the second surface 12. The light is emitted from the light guide member 1.

By the way, in the optical system 100 according to the present embodiment, as shown in FIG. 1A, the optical axis Ax1 of the light incident from the entrance surface 10 is such that the distance to the first surface 11 becomes smaller as the distance from the entrance surface 10 increases. , are inclined with respect to the first surface 11. That is, in the present embodiment, the optical axis Ax1 of the light incident from the entrance surface 10 is not parallel to the first surface 11 but is inclined, and due to the inclination, the farther from the entrance surface 10 the more the optical axis Ax1 of the light enters the first surface 11. It will get closer.

As a result, the light incident from the entrance surface 10 approaches the first surface 11 as it moves away from the entrance surface 10, that is, as it travels inside the light guide member 1, the first surface 11 (including the prism 3) It is easy to be incident on the Therefore, most of the light that has entered from the entrance surface 10 is likely to enter the first surface 11 before reaching the end surface 13 of the light guide member 1 that faces the entrance surface 10 . In other words, most of the light incident from the entrance surface 10 is difficult to reach the end surface 13 of the light guide member 1 on the opposite side to the entrance surface 10, so that light is difficult to leak from the end surface 13. As a result, it is easy to increase the proportion of the light emitted from the second surface 12 to the outside of the light guide member 1 through the direct optical path L1 relative to the light incident from the entrance surface 10, and it is possible to improve the light extraction efficiency. .

Furthermore, in the optical system 100 according to the present embodiment, the light control body 2 has a shape conversion function, as shown in FIG. The shape conversion function converts the shape projected onto the projection surface S1 parallel to the entrance surface 10 from the first shape F1 of the light output from the light source 4 to the second shape F2 of the light incident on the entrance surface 10. It is a function. Here, the projection surface S1 is a "virtual surface" defined inside the light control body 2, and has no substance. In this embodiment, as an example, the projection plane S1 is assumed to be the same plane as the entrance plane 10. That is, in this embodiment, the light control body 2 located between the light source 4 and the entrance surface 10 of the light guide member 1 projects light onto the projection surface S1 (incidence surface 10) parallel to the entrance surface 10. is converted from the first shape F1 to the second shape F2.

Thereby, it is possible to control the range within the light guide member 1 that the light incident from the entrance surface 10 reaches without depending on the first shape F1 that is the shape of the light output from the light source 4. That is, the range within the light guide member 1 that the light incident on the incident surface 10 reaches is due to the second shape F2, which is the shape of the light incident on the incident surface 10, but in the optical system 100, the range that the light incident on the incident surface 10 reaches is due to the second shape F2, which is the shape of the light incident on the incident surface 10. It is possible to transform the shape from F2 to the second shape F2. Therefore, according to this optical system 100, it is possible to control the light that enters from the entrance surface 10 so that the light reaches a relatively wide area inside the light guide member 1. As a result, in the optical system 100, it becomes easier for light to reach the entire area of the first surface 11, and it becomes easier to uniformly extract light from the entire area of the second surface 12, which is the output surface.

Further, in the optical system 100 according to the present embodiment, as shown in FIG. 3, at least one of the first surface 11 and the second surface 12 includes a light distribution control section 14. The light distribution control unit 14 controls the distribution of light extracted from the second surface 12. In this embodiment, as an example, only the second surface 12 of the first surface 11 and the second surface 12 has the light distribution control section 14. That is, the light distribution control section 14 is provided on the second surface 12.

Thereby, the light distribution of the light extracted from the second surface 12 of the light guide member 1 can be controlled by the light distribution control section 14 provided in the light guide member 1. In particular, the light guide member 1 is configured such that light entering the light guide member 1 from the incident surface 10 is emitted from the second surface 12 by only one reflection at the prism 3 inside the light guide member 1. It includes a direct optical path L1. In other words, after the light passing through the direct optical path L1 enters the light guide member 1 from the incident surface 10, it is not reflected by anything other than the prism 3, and is reflected only once by the prism 3, and then from the second surface 12. The light is emitted to the outside of the light guide member 1. Therefore, the shapes of the first surface 11 and the second surface 12 do not contribute to the light guide inside the light guide member 1, and even if the light distribution control section 14 is provided in the light guide member 1, The light guiding performance of the optical member 1 is less likely to deteriorate. As a result, while making light distribution control possible, light can be efficiently extracted from the second surface 12 to the outside of the light guide member 1 through the direct optical path L1, and the light extraction efficiency can be improved.

Further, as shown in FIG. 2, the optical member 20 used as the light control body 2 in the optical system 100 according to the present embodiment includes an entrance lens 21 and an output section 22. The optical member 20 emits the light that has entered the input lens 21 from the light source 4 from the output section 22 . The entrance lens 21 has a main entrance surface 211 and a sub entrance surface 212. The main entrance surface 211 is arranged to face the light source 4 . The sub-incidence surface 212 is oriented toward the normal L21 of the main entrance surface 211. The sub-incidence surface 212 is located on at least a portion of the periphery of the main entrance surface 211 . The optical axis Ax2 of the light source 4 is inclined with respect to the normal L21 of the main entrance surface 211. Here, the normal L21 to the main entrance surface 211 is, for example, the normal to the main entrance surface 211 at the tip (the apex of the dome) if the main entrance surface 211 is dome-shaped. The normal line L21 to the main entrance surface 211 is a "virtual line" and has no substance.

As a result, the optical axis Ax2 of the light source 4 is inclined with respect to the normal L21 of the main entrance surface 211, so that the optical axis Ax2 of the optical member 20 is inclined with respect to the normal L21 of the main entrance surface 211. Light from the light source 4 enters in an asymmetrical manner. Therefore, it is possible to unbalance the intensity of the light incident from the light source 4 onto the main entrance surface 211 of the entrance lens 21 and the sub-incident surface 212 located around it. As a result, the light intake efficiency in the optical member 20 can be improved.

(2) Details Below, the optical system 100 according to the present embodiment, the illumination system 200 using the optical system 100, the display system 300 using the illumination system 200, and the moving object B1 will be explained with reference to FIGS. 1A to 12C. explain in detail.

(2.1) Premise In the following explanation, the width direction of the light guide member 1 (the direction in which the plurality of light sources 4 are lined up in FIG. 3) is the "X-axis direction", and the depth direction of the light guide member 1 (the optical axis in FIG. 1A) The direction in which Ax1 extends) is defined as the "Y-axis direction." 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 lined up in FIG. 1A) is referred to as the "Z-axis direction." The X-axis, Y-axis, and Z-axis that define these directions are orthogonal to each other. Arrows indicating "X-axis direction,""Y-axisdirection," and "Z-axis direction" in the drawings are only shown for explanation and have no substance.

In addition, "extraction efficiency" as used in the present disclosure refers to the amount of light that exits from the second surface 12 (output surface) of the light guide member 1 relative to the amount of light that enters the incident surface 10 of the light guide member 1. refers to the proportion of 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 will increase. become higher (larger). As an example, if the amount of light that enters the incident surface 10 of the light guide member 1 is "100", and the amount of light that exits from the second surface 12 of the light guide member 1 is "10", then , the light extraction efficiency in the light guide member 1 is 10%.

Furthermore, the term "capture efficiency" as used in the present disclosure refers to the ratio of the amount of light taken into the optical member 20 (light controller 2) to the amount of light output from the light source 4. That is, as the relative ratio of the amount of light taken into the optical member 20 to the amount of light output from the light source 4 increases, the light taking efficiency becomes higher (larger). As an example, if the amount of light output from the light source 4 is "100" and the amount of light taken into the optical member 20 is "10", the light intake efficiency in the optical member 20 is 10%. .

Furthermore, the term "optical axis" as used in the present disclosure means a virtual light ray that is representative of the light flux that passes through the entire system. As an example, the optical axis Ax2 of the light source 4 coincides with the rotational symmetry axis of the light emitted from the light source 4.

In addition, "parallel" as used in the present disclosure refers to not only the case where two parties are substantially parallel, that is, the two parties are strictly parallel, but also the case where the angle between the two parties is within a range of several degrees (for example, less than 5 degrees). It means being in a compatible relationship.

In addition, "orthogonal" as used in the present disclosure refers to the case where two parties are substantially orthogonal, that is, the two parties are strictly orthogonal, and the angle between the two parties is several degrees (for example, less than 5 degrees) with respect to 90 degrees. ) refers to a relationship that falls within a range of degrees.

(2.2) Display System First, the display system 300 will be explained with reference to FIGS. 4 and 5.

The illumination system 200 according to this embodiment constitutes a display system 300 together with the display 5, as shown in FIG. In other words, the display system 300 according to this embodiment includes the lighting system 200 and the display 5. The display device 5 receives light emitted from the illumination system 200 and displays an image. The "image" here is an image displayed in a manner that is visible to the user U1 (see FIG. 5), and may be a figure, symbol, character, number, design, photograph, etc., or a combination thereof. . Images displayed on the display system 300 include moving images (moving images) and still images (still images). Furthermore, "video" includes images composed of a plurality of still images obtained by time-lapse photography or the like.

Further, as shown in FIG. 5, the display system 300 according to the present embodiment constitutes a moving body B1 such as a car together with a moving body main body B11. In other words, the mobile body B1 according to this embodiment includes the display system 300 and the mobile body B11. The mobile body B11 is equipped with a display system 300. In this embodiment, as an example, it is assumed that the moving body B1 is a car (passenger car) driven by a person. In this case, the user U1 who visually recognizes the image displayed on the display system 300 is a passenger of the moving body B1, and in this embodiment, as an example, the user U1 is the driver of the automobile as the moving body B1. Assume that U1.

In this embodiment, the display system 300 is used for, for example, a head-up display (HUD) mounted on the moving body B1. The display system 300 is used, for example, to display driving support information related to speed information, condition information, driving information, etc. of the moving body B1 in the field of view of the user U1. The driving information of the mobile body B1 includes, for example, navigation-related information that displays a driving route and the like, and ACC (Adaptive Cruise Control)-related information that keeps the traveling speed and inter-vehicle distance constant.

The display system 300 includes an image display section 310, an optical system 320, and a control section 330, as shown in FIGS. 4 and 5. The display system 300 further includes a housing 340 that houses the image display section 310, the optical system 320, and the control section 330.

The housing 340 is made of, for example, a synthetic resin molded product. The housing 340 accommodates an image display section 310, an optical system 320, a control section 330, and the like. The housing 340 is attached to the dashboard B13 of the mobile body B11. The light reflected by the second mirror 322 (described later) of the optical system 320 is emitted to the reflecting member (windshield B12) through an opening in the upper surface of the housing 340, and the light reflected by the windshield B12 is reflected by the eye box C1. The light is focused on. The reflecting member is not limited to the windshield B12, but may be realized, for example, by a combiner or the like arranged on the dashboard B13 of the mobile body B11.

According to such a display system 300, the user U1 visually recognizes the virtual image projected in the space in front of the moving body B1 (outside the vehicle) through the windshield B12. A "virtual image" as used in the present disclosure means an image formed by the diverging light rays to look like an actual object when the light emitted from the display system 300 diverges at a reflective member such as the windshield B12. Therefore, the user U1 driving the mobile body B1 visually recognizes the image as a virtual image projected by the display system 300, superimposed on the real space spreading in front of the mobile body B1. In short, the display system 300 according to this embodiment displays a virtual image as an image. Images (virtual images) that can be displayed by the display system 300 include a virtual image E1 superimposed along the running surface D1 of the moving body B1, and a virtual image three-dimensionally drawn along a plane PL1 orthogonal to the running surface D1. .

The image display section 310 includes a case 311. The image display unit 310 has a function of displaying a three-dimensional image using a light field method that makes an object appear three-dimensional by reproducing light emitted from the object in a plurality of directions. ing. However, the method by which the image display unit 310 stereoscopically displays a virtual image of the object to be rendered three-dimensionally is not limited to the light field method. The image display unit 310 may employ a parallax method that allows the user U1 to visually recognize a virtual image of a three-dimensionally rendered object by projecting images that are disparate from each other onto the left and right eyes of the user U1.

The image display unit 310 includes a display 5 and an illumination system 200 including an optical system 100. The display device 5 is, for example, a liquid crystal display or the like, and displays an image upon receiving the light emitted from the illumination system 200. That is, the lighting system 200 emits light from behind the display 5 toward the display 5, and the light from the lighting system 200 passes through the display 5, so that the display 5 displays an image. . In other words, the lighting system 200 functions as a backlight for the display 5.

The image display section 310 includes a case 311. The case 311 houses the optical system 100, the illumination system 200 including the light source 4, and the display 5. The lighting system 200 and the display 5 are held in a case 311. Here, the display device 5 is arranged along the top surface of the case 311, and one surface of the display device 5 is exposed from the top surface of the case 311. The lighting system 200 is disposed below the display device 5 in the case 311 and outputs light toward the display device 5 from below the display device 5 . Thereby, the upper surface of the case 311 constitutes a display surface 312 on which an image is displayed.

The image display section 310 is housed inside the housing 340 with the display surface 312 facing a first mirror 321 (described later). The display surface 312 of the image display unit 310 has a shape (for example, a rectangular shape) that matches the range of the image projected onto the user U1, that is, the shape of the windshield B12. On the display surface 312 of the image display section 310, a plurality of pixels are arranged in an array. The plurality of pixels of the image display section 310 emit light under the control of the control section 330, and an image is displayed on the display surface 312 by light output from the display surface 312 of the image display section 310.

The image displayed on the display surface 312 of the image display section 310 is emitted to the windshield B12, and the light reflected by the windshield B12 is focused on the eyebox C1. That is, the image displayed on the display surface 312 is viewed through the optical system 320 by the user U1 who has a viewpoint within the eyebox C1. 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) through the windshield B12.

The optical system 320 focuses the light output from the display surface 312 of the image display section 310 onto the eyebox C1. In this embodiment, the optical system 320 includes, for example, a first mirror 321 that is a convex mirror, a second mirror 322 that is a concave mirror, and a windshield B12.

The first mirror 321 reflects the light output from the image display section 310 and makes it enter 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 makes it enter the eyebox C1.

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

The storage unit 334 is realized, for example, by a non-temporary recording medium such as a rewritable nonvolatile semiconductor memory. The storage unit 334 stores programs and the like executed by the control unit 330. Moreover, as already mentioned, the display system 300 is used to display driving support information related to the speed information, condition information, driving information, etc. of the moving object B1 in the field of view of the user U1. Therefore, the type of virtual image displayed by the display system 300 is determined in advance. The storage unit 334 stores in advance image data for displaying virtual images (the virtual image E1, which is the object of two-dimensional drawing, and the virtual image, which is the object of three-dimensional drawing).

The drawing control unit 331 receives detection signals from various sensors 350 mounted on the moving body B1. The sensor 350 is a sensor for detecting various information used in, for example, an advanced driver assistance system (ADAS). The sensor 350 includes, for example, at least one of a sensor for detecting the state of the moving body B1 and a sensor for detecting the state around the moving body B1. The sensor for detecting the state of the moving body B1 includes, for example, a sensor that measures the vehicle speed, temperature, remaining fuel, etc. of the moving body B1. Sensors for detecting the state around the moving body B1 include an image sensor that photographs the surroundings of the moving body B1, a millimeter wave radar, LiDAR (Light Detection and Ranging), or the like.

Based on the detection signal input from the sensor 350, the drawing control unit 331 acquires one or more pieces of image data for displaying information regarding the detection signal from the storage unit 334. Here, when displaying multiple types of information on the image display unit 310, the drawing control unit 331 acquires multiple image data for displaying the multiple types of information. Further, the drawing control unit 331 obtains position 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 position information of the virtual image to be displayed to the image data creation unit 332.

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

The output unit 333 outputs the image data created by the image data creation unit 332 to the image display unit 310, and causes the display surface 312 of the image display unit 310 to display an image based on the created image data. An image (virtual image) is displayed by the display system 300 by projecting the image displayed on the display surface 312 onto the windshield B12. In this way, the image (virtual image) displayed by the display system 300 is visually recognized by the user U1.

(2.3) Optical System Next, the optical system 100 will be described with reference to FIGS. 1A to 3 and 6A to 7B.

In this embodiment, the optical system 100 includes a light guide member 1, a plurality of light control bodies 2, and a plurality of prisms 3. That is, the optical system 100 according to the present embodiment includes a plurality of light control bodies 2 and further includes a plurality of prisms 3.

Further, in this embodiment, the optical system 100 constitutes the illumination system 200 together with the plurality of light sources 4. That is, the illumination system 200 according to this embodiment includes an optical system 100 and a plurality of light sources 4.

Since the plurality of light control bodies 2 employ a common configuration, hereinafter, unless otherwise specified, the configuration described for one light control body 2 is the same for the other light control bodies 2. Furthermore, since the plurality of prisms 3 have a common configuration, the configuration described below for one prism 3 is the same for the other prisms 3 unless otherwise specified. Further, since the plurality of light sources 4 have a common configuration, the configuration described below for one light source 4 is the same for the other light sources 4 unless otherwise specified.

The light source 4 is, for example, a solid-state light emitting device such as a light emitting diode (LED) device or an organic electro-luminescence (OEL) device. In this embodiment, as an example, the light source 4 is a chip-shaped light emitting diode element. Although such a light source 4 actually emits light over a certain area of its surface (light-emitting surface), it can ideally be regarded as a point light source that emits light from one point on its surface. Therefore, in the following description, it is assumed that the light source 4 is an ideal point light source.

In this embodiment, the light source 4 is arranged to face the entrance surface 10 of the light guide member 1 with a predetermined distance therebetween, as shown in FIG. 2 . A light control body 2 is located between the light source 4 and the entrance surface 10 of the light guide member 1.

In this embodiment, the light control body 2 is integrated with the light guide member 1. "Integrated" in the present disclosure means an aspect in which a plurality of elements (parts) can be physically handled as one. In other words, the phrase "a plurality of elements are integrated" means that the plurality of elements are integrated into one and can be handled as one member. In this case, the plurality of elements may be inseparable, such as an integrally molded product, or the plurality of separately produced elements may be mechanically bonded, for example by welding, gluing, caulking, etc. may be combined with That is, the light guide member 1 and the light control body 2 may be integrated in any suitable manner.

More specifically, in this embodiment, as described above, the light guide member 1 and the light control body 2 are integrated as an integrally molded product. That is, in this embodiment, the light guide member 1 and the light control body 2 are integrally molded and are inseparable from each other. Therefore, as described above, the incident surface 10 of the light guide member 1 is a "virtual surface" defined inside the integrally molded product of the light guide member 1 and the light control body 2, and is not a real surface.

Here, as shown in FIG. 3, the plurality of light sources 4 are arranged at predetermined intervals in the X-axis direction. The plurality of light sources 4 correspond to the plurality of light control bodies 2 on a one-to-one basis. That is, the plurality of light control bodies 2 are also arranged so as to be lined up in the X-axis direction, similarly to the plurality of light sources 4. Here, the pitch of the plurality of light sources 4 and the pitch of the plurality of light control bodies 2 in the X-axis direction are equal.

The light guide member 1 is a member that takes the light from the light source 4 into the light guide member 1 from the incident surface 10 and guides it through the light guide member 1 to the second surface 12 that is the output surface. In this embodiment, the light guide member 1 is, for example, a molded product made of a resin material having translucency, such as acrylic resin, and is formed into a plate shape. That is, the light guide member 1 is a light guide plate having a certain degree of thickness.

As described above, the light guide member 1 has an entrance surface 10 into which light enters, and a first surface 11 and a second surface 12 (output surfaces) that face each other. Furthermore, the light guide member 1 has an end surface 13 facing the entrance surface 10.

Specifically, in this embodiment, as shown in FIGS. 6A to 6D, the light guide member 1 has a rectangular plate shape, and two opposing faces in the thickness direction of the light guide member 1 are the first faces. 11 and the second surface 12. Furthermore, one end surface of the four end surfaces (peripheral surfaces) of the light guide member 1 is the incident surface 10 . That is, the light guide member 1 is formed into a rectangular shape when viewed from above (viewed from one side in the Z-axis direction). Here, as an example, the light guide member 1 is formed in a rectangular shape, the dimension of which is smaller in the Y-axis direction than in the X-axis direction. Both surfaces of the light guide member 1 in the thickness direction (Z-axis direction) constitute a first surface 11 and a second surface 12, respectively. Furthermore, both sides of the light guide member 1 in the transverse direction (Y-axis direction) constitute an incident surface 10 and an end surface 13, respectively.

In this way, one end surface (the left surface in FIG. 1A) of the two end surfaces facing each other in the Y-axis direction of the light guide member 1 is arranged such that the light emitted from the plurality of light sources 4 is directed to the plurality of light controllers, respectively. 2 is the entrance plane 10 through which the light enters. Two surfaces of the light guide member 1 that face each other in the Z-axis direction are a first surface 11 and a second surface 12, respectively. The first surface 11 is the lower surface in FIG. 1A, and the second surface 12 is the upper surface in FIG. 1A. The second surface 12 is an output surface that outputs light from the inside of the light guide member 1 to the outside. Therefore, when light enters the light guide member 1 from one end surface, which is the incident surface 10, the second surface 12, which is the output surface, emits light from the surface.

Further, in this embodiment, the second surface 12 is a plane parallel to the XY plane. Further, the entrance plane 10 is a plane parallel to the XZ plane. The "XY plane" here is a plane that includes the X axis and the Y axis, and is perpendicular to the Z axis. Similarly, the "XZ plane" here is a plane that includes the X axis and the Z axis, and is perpendicular to the Y axis. In other words, the second surface 12 is a plane orthogonal to the Z-axis, and the entrance surface 10 is a plane orthogonal to the Y-axis. Therefore, the second surface 12 and the entrance surface 10 are orthogonal to each other.

On the other hand, the first surface 11 is not parallel to the XY plane, but is a plane inclined to the XY plane. That is, the first surface 11 and the entrance surface 10 are not perpendicular to each other. Specifically, the first surface 11 is inclined with respect to the XY plane so that it approaches the second surface 12 as it moves away from the entrance surface 10. That is, in this embodiment, the first surface 11 and the second surface 12 are inclined to each other.

Further, in this embodiment, a light distribution control section 14 is provided on the second surface 12. The light distribution control section 14 includes a lens. This embodiment includes a cylindrical lens as an example. The light distribution control unit 14 will be described in detail in the section “(2.7) Light distribution control unit”.

The light controller 2 is arranged between the light source 4 and the entrance surface 10 of the light guide member 1 . The light controller 2 controls the light output from the light source 4 and incident on the entrance surface 10 . In this embodiment, the light controller 2 has a collimating function that brings the light output from the light source 4 closer to parallel light. That is, the light control body 2 is a collimating lens that, when light that spreads radially from the light source 4 is incident, condenses the light toward the entrance surface 10 to make it approach parallel light. Here, the light emitted from the light source 4 enters the incident surface 10 of the light guide member 1 through the light control body 2. Therefore, the light from the light source 4 is controlled to narrow the spread angle by the light control body 2 having a collimating function, and is emitted toward the incident surface 10 of the light guide member 1. The present embodiment will be described on the assumption that light from a light source 4 as an ideal point light source is controlled by the light control body 2 into ideal parallel light.

The details will be explained in the section “(2.4) Oblique light incidence”, but in this embodiment, as shown in FIG. 1A, the optical axis Ax1 of the light incident from the incident surface 10 of the light guide member 1 is It is inclined with respect to the first surface 11 so that the distance to the first surface 11 becomes smaller as the distance from the surface 10 increases. Therefore, the parallel light emitted from the light control body 2 to the incident surface 10 of the light guide member 1 is inclined with respect to the first surface 11 such that the distance to the first surface 11 becomes smaller as the distance from the incident surface 10 increases. The result is parallel light. Moreover, the dotted arrows in the drawings conceptually represent light rays (or optical paths), and do not involve any substance.

In this embodiment, as shown in FIG. 3, the plurality of light control bodies 2 are formed so as to be lined up in the X-axis direction at the end forming the entrance surface 10 of the light guide member 1. That is, in this embodiment, the light control body 2 is integrated with the light guide member 1. Moreover, as already mentioned, the plurality of light controllers 2 correspond one-to-one with the plurality of light sources 4, respectively. Therefore, the plurality of light controllers 2 control the spread angle of the light emitted by the corresponding light sources 4, and emit the light to the entrance surface 10. The shape of the light control body 2 will be described in detail in the sections "(2.5) Shape conversion function" and "(2.6) Asymmetric shape."

The prism 3 is provided on the first surface 11 and reflects light passing through the interior of the light guide member 1 toward the second surface 12 . In this embodiment, a plurality of prisms 3 are provided on the first surface 11. The prism 3 is configured to totally reflect the incident light. Of course, the prism 3 is not limited to a mode in which all incident light is totally reflected, but may also include a mode in which some light passes through the interior of the prism 3 without being totally reflected.

In the light guide member 1, most of the light incident from the incident surface 10 is reflected at the prism 3 without being reflected at the first surface 11 or the second surface 12 except for the prism 3. , are emitted from the second surface 12. In other words, the light guide member 1 includes a direct optical path L1 in which light that enters from the entrance surface 10 is directly reflected by the prism 3 and exits from the second surface 12.

In this embodiment, the prism 3 is formed on the first surface 11 so that the cross section 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 FIG. 1B, the prism 3 has a reflective surface 30 that reflects light incident through the interior of the light guide member 1 toward the second surface 12. FIG. 1B is an enlarged schematic end view of region A1 in FIG. 1A.

The angle θ1 between the reflective surface 30 and the first surface 11 (that is, the inclination angle of the reflective surface 30) is such that the incident angle θ0 of light incident on the reflective surface 30 is equal to or greater than the critical angle. That is, the reflective surface 30 is inclined with respect to the first surface 11 so that the incident light is totally reflected. Further, the inclination angle θ1 of the reflective surface 30 is set such that the light totally reflected by the reflective surface 30 is incident on the second surface 12 in a direction perpendicular to the second surface 12.

In this embodiment, as shown in FIGS. 7A and 7B, the plurality of prisms 3 are arranged in a zigzag pattern on the first surface 11 when viewed from one side in the Z-axis direction. Here, FIG. 7A is an enlarged schematic plan view of region A1 in FIG. 6C. FIG. 7B is a drawing schematically showing an end surface taken along line B1-B1 in FIG. 7A. Although only a part of the first surface 11 is shown in FIG. 7A, a plurality of prisms 3 are actually formed over substantially the entire first surface 11.

Specifically, each prism 3 has a length in the X-axis direction, and a plurality of prisms 3 are lined up at intervals in the longitudinal direction (X-axis direction). Furthermore, the plurality of prisms 3 are formed so as to be spaced apart from each other in the Y-axis direction as well. When the rows of prisms lined up in the X-axis direction are the first row, second row, third row, etc. counting from the entrance surface 10 side in the Y-axis direction, the plurality of prisms included in the even-numbered rows 3 and the plurality of prisms 3 included in the odd-numbered rows are located at positions shifted from each other in the X-axis direction. Here, the plurality of prisms 3 included in the even-numbered rows and the plurality of prisms 3 included in the odd-numbered rows are arranged so that their longitudinal direction (X-axis direction) ends overlap in the Y-axis direction. has been done. According to this arrangement, the plurality of prisms 3 are lined up in the X-axis direction without gaps when viewed from the entrance surface 10, and the light that enters the inside of the light guide member 1 from the entrance surface 10 is transmitted through the plurality of prisms 3. The light will be reflected by one of the three prisms 3.

In this embodiment, as an example, the plurality of prisms 3 all have the same shape. Therefore, as shown in FIG. 7B, in the plurality of prisms 3 lined up in the Y-axis direction, the inclination angle θ1 of the reflective surface 30 is the same angle. Further, the sizes of the prisms 3, such as the longitudinal dimension of the prisms 3 and the depth of the recess as the prisms 3 (in other words, the height of the prisms 3), are also the same for the plurality of prisms 3. That is, in this embodiment, a plurality of prisms 3 are provided so as to be lined up in the direction in which light enters the entrance surface 10 (Y-axis direction). Here, the plurality of prisms 3 have the same shape. Therefore, if the incident angle θ0 of the light incident on the reflective surface 30 is constant, no matter which prism 3 among the plurality of prisms 3 the light is incident on, the light reflected on the reflective surface 30 of the prism 3 will be The directions will be the same. Therefore, all the light reflected by the plurality of prisms 3 can be made to enter the second surface 12 in a direction perpendicular to the second surface 12.

Furthermore, as an example, the depth of the concave portion as the prism 3 (in other words, the height of the prism 3) is 1 μm or more and 100 μm or less. Similarly, as an example, the pitch of the plurality of prisms 3 in the Y-axis direction is 1 μm or more and 1000 μm or less. As a specific example, the depth of the concave portion as the prism 3 is more than 10 μm, and the pitch of the plurality of prisms 3 in the Y-axis direction is more than 100 μm.

Hereinafter, the light emission principle of the optical system 100 of this embodiment will be explained using FIG. 1A and FIG. 1B.

First, as shown in FIG. 1A, the light emitted from the light source 4 passes through the corresponding light control body 2 to have its spread angle controlled. Then, light whose spread angle is controlled is emitted from the light control body 2 toward the entrance 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 enters the incident surface 10 perpendicularly.

Moreover, as already mentioned, the optical axis Ax1 of the light entering from the entrance surface 10 of the light guide member 1 is set to the first surface 11 such that the distance to the first surface 11 becomes smaller as the distance from the entrance surface 10 increases. It is slanted against. Therefore, most of the light that enters the incident surface 10 reaches the first surface 11 without reaching the second surface 12 and the end surface 13 of the light guide member 1 that faces the incident surface 10 .

As shown in FIG. 1B, most of the light incident on the incident surface 10 is not reflected on the first surface 11 and the second surface 12, and is reflected by the plurality of prisms 3 provided on the first surface 11. The light is totally reflected by the reflecting surface 30 of one of the prisms 3. That is, the light guide member 1 includes a direct optical path L1 in which light that enters from the incident surface 10 is directly reflected by the prism 3 and exits from the second surface 12. Furthermore, in this embodiment, the direct optical path L1 includes an optical path of light that is totally reflected by the prism 3. The light totally reflected by the reflective surface 30 of the prism 3 follows an optical path orthogonal to the second surface 12 and is emitted from the second surface 12 .

Here, in this embodiment, as described above, the inclination angles θ1 of the reflective surfaces 30 in the plurality of prisms 3 are the same angle. When parallel light parallel to the second surface 12 is incident on such a plurality of prisms 3, the incident angle θ0 of the light incident on the reflective surface 30 is also constant. Therefore, in any prism 3 among the plurality of prisms 3, the direction of the light reflected by the reflective surface 30 is the same. Therefore, in this embodiment, all the light that reaches the second surface 12 on the direct optical path L1 is incident on the second surface 12 at the same angle. The "same angle" as used herein is not limited to strictly the same angle, but may include an error of up to about 2 or 3 degrees. Ideally, all the light that reaches the second surface 12 on the direct optical path L1 is incident on the second surface 12 at 90 degrees, that is, in a perpendicular direction.

In this embodiment, since the plurality of prisms 3 are arranged over the entire second surface 12, the light that has passed through the direct optical path L1 as described above is distributed throughout the entire second surface 12 of the light guide member 1. It is emitted without any problem. As a result, the entire second surface 12 emits surface light.

Hereinafter, the advantages of the optical system 100 of this embodiment will be explained with a comparison with a general light guide member (light guide plate).

In a general light guide member, the light that enters from the incident surface of the light guide member is reflected multiple times on both sides of the light guide member in the thickness direction (corresponding to the first surface 11 and the second surface 12). , the light is guided inside the light guiding member. The prism provided on one surface in the thickness direction of the light guide member (corresponding to the first surface 11) breaks the condition for total reflection (that is, angle of incidence ≧ critical angle), so that the prism serves as the light emitting surface. Light is emitted from the other surface (corresponding to the second surface 12) of the optical member in the thickness direction. As a result, even in a general light guide member, the entire emission surface emits light from the surface.

However, in the general light guide member described above, the light that enters from the incident surface of the light guide member is reflected multiple times on both sides of the light guide member in the thickness direction, so that the light is reflected from the incident surface in the light guide member. Light is guided to distant areas. Therefore, as the number of total reflections of light increases, the conditions for total reflection (that is, angle of incidence ≧ critical angle) are likely to collapse, and light from one surface in the thickness direction of the light guide member (corresponding to the first surface 11) is more likely to leak.

In particular, when an optical system including a light guide member is applied to a head-up display mounted on the moving body B1 like the display system 300 according to the present embodiment, the light guide member has a relatively narrow viewing angle. , high light intensity is required. That is, in a head-up display, it is preferable that the light distribution is controlled from the light guide member in accordance with the optical system 320, so the viewing angle is narrower than that of the light guide member for the backlight of a general liquid crystal display. required. Since it is difficult to narrow the viewing angle with a general light guide member, when a general light guide member is used in a head-up display, light is likely to be emitted in unnecessary directions.

On the other hand, since the optical system 100 according to the present embodiment includes the light controller 2 and the prism 3 as described above, most of the light that enters the incident surface 10 of the light guide member 1 follows the direct optical path L1. I will follow it. That is, in this embodiment, most of the light that enters the incident surface 10 of the light guide member 1 directly enters the prism 3 without repeating total reflection at the first surface 11 and the second surface 12. The light will be emitted from the second surface 12. Therefore, in this embodiment, unlike general light guiding members, the conditions for total reflection are not disrupted, so light is less likely to leak from the first surface 11, and as a result, the light extraction efficiency is improved. can be achieved. Furthermore, since most of the light that enters the incident surface 10 is parallel light, the light is difficult to spread, and even for the light that is reflected by the prism 3 and exits from the second surface 12, a relatively narrow exit angle can be maintained. In the optical system 100 according to the present embodiment, a relatively large light intensity can be achieved by using the direct optical path L1 while emitting most of the light incident on the entrance surface 10 at such a narrow angle.

In this embodiment, the light emitted from the second surface 12 in the direct optical path L1 is 50% or more of the light that enters the light guide member 1 from the entrance surface 10. That is, although some of the light that enters the entrance surface 10 of the light guide member 1 may not pass through the direct optical path L1, in this embodiment, most (more than half) of the light that enters the entrance surface 10, The light is emitted from the second surface 12 through the direct optical path L1. Thereby, the light extraction efficiency in the light guide member 1 is at least 50%. The light extraction efficiency in the light guide member 1 is more preferably 70% or more, and may further be 80% or more.

In this way, by improving the light extraction efficiency in the light guide member 1, on the first surface 11 side of the light guide member 1, a reflective sheet, a prism sheet, a reflective polarizing film (DBEF: Dual Brightness Enhancement Film) , optical elements such as Fresnel lens sheets become unnecessary. In other words, since light is difficult to leak from the first surface 11, sufficient light extraction efficiency can be achieved without the need to arrange these optical elements on the first surface 11 side of the light guide member 1.

(2.4) Oblique Light Entry Next, the configuration regarding light entry (light incidence) from the entrance surface 10 of the light guide member 1 will be described in detail with reference to FIGS. 1A and 1B.

That is, in the optical system 100 according to the present embodiment, as shown in FIG. 1A, the optical axis Ax1 of the light incident from the entrance surface 10 is such that the distance to the first surface 11 becomes smaller as the distance from the entrance surface 10 increases. , are inclined with respect to the first surface 11. In particular, in this embodiment, parallel light enters the incident surface 10 of the light guide member 1 from the light control body 2, so that all light rays included in this parallel light are inclined with respect to the first surface 11. It turns out. Moreover, in this embodiment, the first surface 11 is a flat surface, and the light rays included in the parallel light incident on the incident surface 10 of the light guide member 1 are inclined at the same angle with respect to the first surface 11.

Specifically, the first surface 11 and the second surface 12 are non-parallel and inclined to each other. That is, as described above, the second surface 12 is a plane parallel to the XY plane, whereas the first surface 11 is not parallel to the XY plane, but is parallel to the XY plane. It is a plane inclined to the opposite side. Here, the first surface 11 is inclined with respect to the XY plane so that it approaches the second surface 12 as it moves away from the entrance surface 10. In short, in the light guide member 1, the first surface 11 and the second surface 12, which are both surfaces in the thickness direction, are inclined to each other, so that the thickness is not constant, but gradually becomes thinner in a certain direction. Change. In this embodiment, the first surface 11 is inclined with respect to the second surface 12 in the Y-axis direction so that it approaches the second surface 12 as it moves away from the entrance surface 10. Therefore, the thickness of the light guide member 1 is greatest at the end on the side of the incident surface 10, and gradually decreases as it moves away from the incident surface 10, that is, as it approaches the end surface 13 in the Y-axis direction.

On the other hand, the light that enters from the entrance surface 10 is controlled by the light control body 2 into parallel light that is parallel to the second surface 12 . That is, the optical axis Ax1 of the light entering from the entrance surface 10 is parallel to the second surface 12. Therefore, the optical axis Ax1 of the light incident from the incident surface 10 is inclined at a predetermined inclination angle with respect to the first surface 11, and the inclination angle is The angle of inclination of the first surface 11 is the same as that of the first surface 11.

More specifically, as shown in FIG. 1A, the light controller 2 includes a path generating section 23 that forms light paths L31, L32, and L33 between the light source 4 and the entrance surface 10. The path generation unit 23 extends along a straight line (here, the optical axis Ax1) that is inclined with respect to the first surface 11 when viewed from the entrance surface 10, and creates a light path L31 between the light source 4 and the entrance surface 10. , L32, and L33. That is, in this embodiment, the light control body 2 is integrated with the light guide member 1, as described above.

In other words, the light control body 2 includes a portion (path generation portion 23) that protrudes along the optical axis Ax1 that is inclined with respect to the first surface 11 when viewed from the entrance surface 10 of the light guide member 1. The light control body 2 forms light paths L31, L32, and L33 between the light source 4 and the entrance surface 10 in the path generation section 23. Therefore, the light from the light source 4 passes through the path generation section 23 of the light control body 2 and enters the entrance surface 10 along the optical axis Ax1 that is inclined with respect to the first surface 11. That is, the light from the light source 4 passes through the inside of the light control body 2 (the path generation section 23) and enters the incident surface 10 of the light guide member 1. In this way, the optical axis Ax1 of the light incident from the entrance surface 10 is inclined with respect to the first surface 11 at a predetermined angle of inclination.

According to the configuration described above, the light that enters the light guide member 1 from the entrance surface 10 passes through the inside of the light guide member 1 and enters the first surface 11 obliquely. In other words, the light that enters the light guide member 1 from the entrance surface 10 actively enters the first surface 11 . At this time, as the light enters the plurality of prisms 3 formed on the first surface 11, the light is reflected toward the second surface 12 at the reflective surface 30 of the prism 3, as shown in FIG. 1B. be done. Thereby, the light that has entered the light guide member 1 from the entrance surface 10 will be emitted from the second surface 12 through the direct optical path L1.

In this way, the light incident from the incident surface 10 approaches the first surface 11 as it moves away from the incident surface 10, that is, as it travels inside the light guide member 1, ). Therefore, most of the light that has entered from the entrance surface 10 is likely to enter the first surface 11 before reaching the end surface 13 of the light guide member 1 that faces the entrance surface 10 . In particular, by actively directing the incident light toward the first surface 11, while reducing the dimension of the light guide member 1 in the Y-axis direction, most of the light incident from the incident surface 10 can be directed to the direct optical path L1. The light can be emitted from the second surface 12. In other words, it is possible to efficiently emit light from the second surface 12 while suppressing light leakage from the end surface 13. As a result, it is easy to increase the proportion of the light emitted from the second surface 12 to the outside of the light guide member 1 through the direct optical path L1 to the light incident from the entrance surface 10, and it is possible to improve the light extraction efficiency. .

Moreover, in this embodiment, as shown in FIG. 1A, the end surface 13 is divided into two parts, an inclined surface 131 and a vertical surface 132, in the Z-axis direction. In other words, the end surface 13 includes an inclined surface 131 and a vertical surface 132. The inclined surface 131 is a plane that is inclined with respect to the entrance surface 10 such that the distance from the entrance 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 plane 132 is a plane parallel to the entrance plane 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.

Because the end surface 13 has such an inclined surface 131, even if some of the light incident from the entrance surface 10 reaches the end surface 13 without entering the first surface 11, this light can be emitted from the second surface 12. That is, when a part of the light incident from the incident surface 10 enters the inclined surface 131 of the end surface 13, this light is totally reflected by the inclined surface 131 toward the second surface 12, and is emitted from the second surface 12. be done. As a result, in addition to the light emitted from the second surface 12 to the outside of the light guide member 1 through the direct optical path L1, even the light that has reached the end surface 13 can be effectively extracted from the second surface 12. Further improvement in efficiency can be achieved.

(2.5) Shape Conversion Function Next, the shape conversion function of the light control body 2 will be explained in detail with reference to FIG. 2 and FIGS. 8A to 11B.

That is, in the optical system 100 according to the present embodiment, as shown in FIG. It has a shape conversion function of converting the first shape F1 of light incident on the entrance surface 10 into the second shape F2. In FIG. 2, a shape (first shape F1) projected onto the projection surface S1 for light output from the light source 4, and a shape projected onto the projection surface S1 (second shape F1) for light incident on the incident surface 10 are shown. Shape F2) is schematically depicted in each balloon. In this way, in this embodiment, the light controller 2 has a collimating function that brings the light output from the light source 4 closer to parallel light, and also controls the projection shape of the light onto the projection surface S1 (here, the incident surface 10). It has a shape conversion function.

According to the shape conversion function, the projection shape of the light output from the light source 4 on the projection surface S1 is transformed from the first shape F1 to the second shape F2, and the light is incident on the entrance surface 10. The second shape F2 is a shape converted by the shape conversion function based on the first shape F1, and is a different shape from the first shape F1. In this embodiment, as an example, as shown in FIG. 2, the first shape F1 is a shape based on a circle, whereas the second shape F2 is a shape based on a square.

More specifically, the second shape F2 is a shape obtained by deforming the first shape F1, which is based on a circle, so as to approximate a quadrangle by protruding at least one corner F21. In other words, the second shape F2 is a shape obtained by expanding the first shape F1 so as to stretch it in all directions. According to such a shape conversion function, the first shape F1 is approximated by the inscribed circle of the second shape F2. Therefore, the circumscribed circle of the second shape F2 is larger than the circumscribed circle of the first shape F1.

In other words, the second shape F2 is a shape in which at least one corner F21 is added to the first shape F1 so that the first shape F1 approaches a polygonal shape. According to such a shape conversion function, light is incident on the incident surface 10 such that its projection (irradiation) area becomes the second shape F2, which is less rounded than the first shape F1. become. Therefore, by allowing the light to enter near the corners of the incident surface 10, more uniform light will be incident over the entire area of the incident surface 10.

In this embodiment, as described above, a plurality of light sources 4 and a plurality of light control bodies 2 are provided. Therefore, by using the shape conversion function of the plurality of light controllers 2 to convert the shape of the light incident on the incident surface 10 for the light incident from the corresponding light source 4, the shape of the light incident on the incident surface 10 can be more uniformly distributed over the entire area of the incident surface 10. light will be incident. For example, when light having a first shape F1 based on a circle is incident on the incident surface 10, a gap or an overlapping portion is likely to occur between the lights incident on the incident surface 10 from two adjacent light sources 4. On the other hand, when the light having the second shape F2 based on a rectangle enters the entrance surface 10, there is a gap or an overlapping area between the lights that enter the entrance surface 10 from two adjacent light sources 4. Hard to occur.

The shape conversion function as described above can be realized, for example, by the configuration of the light control body 2 described below.

That is, in this embodiment, as shown in FIGS. 8A to 8C, the light control body 2 (optical member 20) includes an entrance lens 21. FIG. 8B is a sectional view taken along the line B1-B1 in FIG. 8A. FIG. 8C is a sectional view taken along the line C1-C1 in FIG. 8A.

The entrance lens 21 has a main entrance surface 211 and a sub entrance surface 212. The main entrance surface 211 is arranged to face the light source 4 . The sub-incidence surface 212 is oriented toward the normal L21 of the main entrance surface 211. The sub-incidence surface 212 is located on at least a portion of the periphery of the main entrance surface 211 . The sub-incidence surface 212 may be parallel to the normal L21 of the main entrance surface 211 (that is, not inclined) or may be inclined.

Here, the entrance lens 21 takes in the light output from the light source 4 through the main entrance surface 211 and the sub-incident surface 212 . Therefore, at least a part of the light from the light source 4, when passing through the entrance lens 21, hits the main entrance surface 211 or the sub-incidence surface 212 depending on the angle of incidence of the light beam with respect to the main entrance surface 211 or the sub-incidence surface 212. It is refracted. In this manner, the light control body 2 refracts at least a portion of the light that has entered the main entrance surface 211 or the sub-incidence surface 212, thereby emitting the light toward the entrance surface 10 of the light guide member 1.

Further, the light control body 2 further includes an outer circumferential surface 213. The outer circumferential surface 213 is located on the opposite side to the normal L21 of the main entrance surface 211 when viewed from the sub-incidence surface 212. The outer circumferential surface 213 totally reflects the light that has entered the light control body 2 from the sub-incident surface 212 toward the incident surface 10 of the light guide member 1 . That is, at least a portion of the light that has entered the light control body 2 from the sub-incidence surface 212 is totally reflected by the outer circumferential surface 213 and is emitted toward the incidence surface 10 of the light guide member 1 .

By the way, the light control body 2 has a plurality of lens surfaces 201 to 205 on the surface facing the light source 4. The "opposing surface" here means the opposing surface, that is, the surface of the light control body 2 facing the light source 4, which is the surface of the light control body 2 that faces the light source 4. In this embodiment, as an example, the surface of the light control body 2 facing the light source 4 is made up of the entrance lens 21 of the light control body 2 . As described above, the entrance lens 21 has a main entrance surface 211 and a sub-incident surface 212. In this embodiment, for example, the sub-incident surface 212 is divided into a plurality of lens surfaces 201 to 205. There is. The sub-incidence surface 212 is divided into a plurality of (here, five) lens surfaces 201 to 205 in the circumferential direction centered on the axis of the light control body 2 facing the light source 4. The "opposing axes" herein mean virtual axes extending in opposing directions. That is, the axis of the light control body 2 facing the light source 4 is a virtual axis extending from the light control body 2 along the direction in which the light control body 2 and the light source 4 face each other. In this embodiment, as an example, the axis of the light controller 2 facing the light source 4 is the normal L21 of the main entrance surface 211 (see FIG. 2).

The angle of inclination of the surface of the light controller 2 facing the light source 4 with respect to the axis facing the light source 4 differs in the circumferential direction around the facing axis. Specifically, the surface of the light control body 2 facing the light source 4 (here, the entrance lens 21) includes a plurality of lens surfaces 201 to 205, as described above. The inclination angles of the plurality of lens surfaces 201 to 205 with respect to the opposing axis (here, the normal L21) are not constant in the circumferential direction around the opposing axis. Specifically, the angle of inclination of the lens surfaces 202, 204 with respect to the opposing axis is greater than the angle of inclination of the lens surfaces 201, 203, 205 with respect to the opposing axis. In other words, the lens surfaces 202 and 204 are configured to have a larger inclination with respect to the normal L21 than the lens surfaces 201, 203, and 205.

Further, the surface of the light control body 2 facing the light source 4 has an asymmetrical shape in one direction perpendicular to the axis of facing the light source 4 (here, the normal line L21). In this embodiment, the entrance lens 21, which is the surface of the light control body 2 facing the light source 4, has an asymmetric shape in the Z-axis direction. Specifically, when viewed from the main entrance surface 211, the entrance lens 21 has a sub-incidence surface 212 (lens surfaces 202, 203, 204) only on one side in the Z-axis direction, and the other side in the Z-axis direction has It's open.

According to the configuration described above, the shape conversion function can be realized in the light control body 2, and the range where the light incident from the incident surface 10 reaches inside the light guide member 1 is covered by the light output from the light source 4. It is possible to control without depending on the first shape F1 which is the shape of .

9A to 11B are drawings showing comparison results between the light control body 2 of the optical system 100 according to the present embodiment and the light control body 2X according to the comparative example. In the light control body 2X according to the comparative example, the sub-incidence surface 212 is not divided into a plurality of lens surfaces 201 to 205, but consists of one continuous curved surface.

In FIGS. 9A to 11B, the range where the light from the light source 4 reaches is schematically represented by a shaded area (dot). Here, the shaded areas are set in three levels depending on the intensity of light from the light source 4, and the areas with higher light intensity are shaded darker. FIG. 11A shows the light guide member 1 when viewed from the first surface 11 side in the thickness direction (Z-axis direction) when light is emitted from the light controller 2 to the light guide member 1 according to the present embodiment. It represents the intensity distribution of light (strictly speaking, the illuminance distribution) on one surface 11. FIG. 11B shows the first light guide member 1 when viewed from the first surface 11 side in the thickness direction (Z-axis direction) when light is emitted from the light controller 2X according to the comparative example to the light guide member 1. It represents the intensity distribution (strictly speaking, illuminance distribution) of light on the surface 11. FIGS. 11A and 11B both represent the intensity distribution (illuminance distribution) of light incident on the light guide member 1 from one light control body 2, 2X.

That is, in the light control body 2 according to this embodiment, as shown in FIG. 9A and FIG. It spreads over a relatively wide area. In particular, according to the shape conversion function of the light control body 2, the projected shape on the projection surface S1 (incidence surface 10) changes from a first shape F1 (see FIG. 2) based on a circle to a second shape F1 based on a square. It is converted into shape F2 (see FIG. 2). Specifically, compared to the light incident on the lens surfaces 201, 203, and 205, the light incident on the lens surfaces 202 and 204 has a normal A position further away from line L21 is reached. In other words, since the lens surfaces 202 and 204 have a larger inclination angle with respect to the opposing axis (here, the normal L21) than the lens surfaces 201, 203, and 205, the light rays incident on the lens surfaces 202 and 204 are It is refracted so that the angle of inclination to the As a result, the light entering from the lens surfaces 202 and 204 of the sub-incidence surface 212 can easily reach the corners of the light control body 2.

On the other hand, in the light control body 2X according to the comparative example, as shown in FIGS. 9B and 10B, the light output from the light source 4 enters the light control body 2X from the entrance lens 21, and the light control body 2X It remains within a relatively narrow range. Specifically, the light incident on the sub-incidence surface 212 spreads uniformly when viewed from one of the extending directions of the normal line L21 of the main incidence surface 211, and only within a certain range from the normal line L21. not reached. As a result, it is difficult for the light to reach the corners of the light control body 2X, and compared to the light control body 2 according to the present embodiment, the range that the light reaches when viewed from one of the extending directions of the normal line L21 of the main entrance surface 211 is becomes narrower.

Therefore, according to the light control body 2 according to this embodiment, the light that enters from the entrance surface 10 spreads over a relatively wide range even inside the light guide member 1, as shown in FIG. 11A. On the other hand, according to the light control body 2X according to the comparative example, as shown in FIG. 11B, the range where the light incident from the entrance surface 10 reaches is limited to a relatively narrow range even inside the light guide member 1. become. More specifically, according to the light control body 2 according to the present embodiment, as shown in FIG. 11A, when the light guide member 1 is viewed from one side in the thickness direction (Z-axis direction), a substantially rectangular region light reaches. On the other hand, according to the light control body 2X according to the comparative example, as shown in FIG. 11B, when the light guide member 1 is viewed from one side in the thickness direction (Z-axis direction), the light control body 2 Light arrives. Therefore, when light enters the light guide member 1 from a plurality of light controllers 2, in this embodiment, compared to the comparative example, the light reaches the entire first surface 11 more easily and the second surface 12 It becomes easier to extract light uniformly from the entire area.

(2.6) Asymmetrical Shape Next, the asymmetrical shape of the light control body 2 will be explained in detail with reference to FIG. 2 and FIGS. 12A to 12C.

That is, the optical member 20 used as the light control body 2 in the optical system 100 according to the present embodiment includes an entrance lens 21 and an output section 22, as shown in FIG. The optical member 20 emits the light that has entered the input lens 21 from the light source 4 from the output section 22 . The entrance lens 21 has a main entrance surface 211 and a sub entrance surface 212. The main entrance surface 211 is arranged to face the light source 4 . The sub-incidence surface 212 is oriented toward the normal L21 of the main entrance surface 211. The sub-incidence surface 212 is located on at least a portion of the periphery of the main entrance surface 211 . The optical axis Ax2 of the light source 4 is inclined with respect to the normal L21 of the main entrance surface 211.

In the example of FIG. 2, the optical axis Ax2 of the light source 4 is inclined by an inclination angle θ2 toward the first surface 11 with respect to the normal L21 of the main entrance surface 211 when viewed from one side in the X-axis direction. There is. Here, the optical axis Ax2 of the light source 4 and the normal L21 to the main entrance surface 211 are both parallel to the YZ plane. The "YZ plane" here is a plane that includes the Y axis and the Z axis, and is perpendicular to the X axis. In other words, the optical axis Ax2 of the light source 4 and the normal L21 to the main entrance surface 211 are both orthogonal to the X-axis.

More specifically, the optical axis Ax2 of the light source 4 and the normal L21 to the main entrance surface 211 intersect on the surface (light emitting surface) of the light source 4. In other words, the light source 4 is arranged such that the center point of its light emitting surface is located on the normal L21 of the main entrance surface 211. In addition, the light source 4 is held in a posture inclined toward the first surface 11 by an inclination angle θ2. As a result, the light from the light source 4 enters the entrance lens 21 of the optical member 20 in an asymmetric manner with respect to the normal L21 of the main entrance surface 211.

By the way, the light source 4 has directivity, and the intensity of the light output from the light source 4 changes depending on the direction seen from the light source 4. For example, if the maximum intensity of the light rays emitted from the light source 4 is "100%" and the intensity of each light ray from the light source 4 is expressed as a percentage of the maximum intensity, the light emitted from the light source 4 will be: Rays of varying intensities are included, such as 10%, 20% or 30%. In the following, it is assumed that the intensity of the light beam on the optical axis Ax2 of the light source 4 is the maximum intensity, that is, the intensity is 100%, and that the intensity of the light beam becomes smaller as the angle with respect to the optical axis Ax2 becomes larger.

The light beam that has entered the entrance lens 21 from the light source 4 includes a principal ray L11, a first auxiliary ray L12, and a second auxiliary ray L13, as shown in FIG. 12A. The first auxiliary ray L12 and the second auxiliary ray L13 both have lower intensity than the principal ray L11. Here, the principal ray L11, the first auxiliary ray L12, and the second auxiliary ray L13 are arranged in the direction orthogonal to the normal L21 of the main entrance surface 211. Line up in order. The first auxiliary ray L12 and the second auxiliary ray L13 only need to have a lower intensity than the principal ray L11. For example, if the intensity of the principal ray L11 is 90%, the first auxiliary ray L12 and the second auxiliary ray L13 The intensities of L13 are all less than 90%. The intensities of the first auxiliary light beam L12 and the second auxiliary light beam L13 may be the same or may be different from each other.

Specifically, in the Z-axis direction perpendicular to the normal L21 of the main entrance surface 211, these light rays are transmitted from the first surface 11 side (downward in FIG. 12A) to the principal ray L11, the first auxiliary ray L12, and the The two auxiliary light beams L13 are arranged in this order. That is, the principal ray L11, the first auxiliary ray L12, and the second auxiliary ray L13 are arranged from the first surface 11 side in descending order of intensity.

Here, in this embodiment, the intensity of the chief ray L11 is the maximum intensity among the light rays that entered the entrance lens 21 from the light source 4. That is, the intensity of the chief ray L11 is 100%. In contrast, the intensities of the first auxiliary light beam L12 and the second auxiliary light beam L13 are both less than 100%. In this embodiment, as an example, it is assumed that the intensities of the first auxiliary light ray L12 and the second auxiliary light ray L13 are both 70%. That is, the intensities of the first auxiliary light beam L12 and the second auxiliary light beam L13 are the same.

On the other hand, as shown in FIG. 12A, the light rays emitted from the light source 4 include a principal ray L11, a first auxiliary ray L12, and a second auxiliary ray L13, as well as a third auxiliary ray L14 and a fourth auxiliary ray L15. . The third auxiliary ray L14 and the fourth auxiliary ray L15 each have a lower intensity than both the first auxiliary ray L12 and the second auxiliary ray L13. The intensities of the third auxiliary light ray L14 and the fourth auxiliary light ray L15 may be the same or different from each other. In this embodiment, as an example, it is assumed that the intensities of the third auxiliary light ray L14 and the fourth auxiliary light ray L15 are both 10%. That is, the intensities of the third auxiliary light beam L14 and the fourth auxiliary light beam L15 are the same.

In the example of FIG. 12A, neither the third auxiliary ray L14 nor the fourth auxiliary ray L15 enters the optical member 20. That is, the third auxiliary light ray L14 and the fourth auxiliary light ray L15 do not reach the entrance surface 10 of the light guide member 1. However, the third auxiliary ray L14 and the fourth auxiliary ray L15 have sufficiently low intensity compared to the principal ray L11, the first auxiliary ray L12, and the second auxiliary ray L13, so they do not reach the incident surface 10. Losses are small.

Furthermore, in this embodiment, the chief ray L11 is incident on the sub-incidence surface 212. That is, the principal ray L11 is incident on the sub-incidence surface 212 of the main-incidence surface 211 and the sub-incidence surface 212 of the entrance lens 21. The principal ray L11 that has entered the sub-incidence surface 212 is refracted by the sub-incidence surface 212, and is totally reflected at the outer circumferential surface 213 toward the entrance surface 10, as shown in FIG. 12A. Thereby, the chief ray L11 is emitted from the emitting section 22 toward the incident surface 10.

Further, the sub-incidence surface 212 has an asymmetrical shape with respect to the normal L21 of the main entrance surface 211. In this embodiment, the entrance lens 21 has an asymmetric shape in the Z-axis direction. Specifically, when viewed from the main entrance surface 211, the entrance lens 21 has a sub-incidence surface 212 (lens surfaces 202, 203, 204) only on one side in the Z-axis direction, and the other side in the Z-axis direction has It's open.

In other words, light rays with relatively high intensity including the principal ray L11, the first auxiliary ray L12, and the second auxiliary ray L13 are and concentrate on the first surface 11 side (lower side in FIG. 12A). Therefore, the optical member 20 (light control body 2) has an asymmetrical shape in which the input lens 21 is concentrated only in the part where relatively high-intensity light rays are concentrated, and the opposite side (upper part of FIG. 12A) is simplified. By employing this, it is easy to keep the dimension t1 in the Z-axis direction small.

On the other hand, FIG. 12B shows an optical system 100Y as a comparative example including an optical member 20Y, and an illumination system 200Y including the optical system 100Y. In the illumination system 200Y according to this comparative example, the optical member 20Y has a symmetrical shape with respect to the normal L21 of the main entrance surface 211 in the Z-axis direction. Specifically, the optical member 20Y has a configuration that is symmetrical to the configuration on the first surface 11 side (lower side in FIG. 12A) when viewed from the normal L21 of the main entrance surface 211 in the optical member 20 according to the present embodiment. , is adopted on the opposite side (upper part of FIG. 12A).

Furthermore, in the illumination system 200Y according to the comparative example, the optical axis Ax2 of the light source 4 is located on the normal line L21 of the main entrance surface 211. That is, in the comparative example, the optical axis Ax2 of the light source 4 is parallel to the normal L21 of the main entrance surface 211.

In such a comparative example, the principal ray L11 is located on the optical axis Ax2 of the light source 4, as shown in FIG. 12B. Further, in the Z-axis direction, a third auxiliary ray L14 and a fourth auxiliary ray L15 are located on both sides of the principal ray L11, and a first auxiliary ray L12 and a second auxiliary ray L13 are located further on both sides thereof. As a result, in the illumination system 200Y according to the comparative example, all light rays with relatively high intensity, including the principal ray L11, the first auxiliary ray L12, and the second auxiliary ray L13, reach the incident surface 10 of the light guide member 1. incident. However, since the optical member 20Y according to the comparative example adopts a symmetrical shape in the Z-axis direction, the dimension t2 in the Z-axis direction is larger than the dimension t1 of the optical member 20 according to the present embodiment.

On the other hand, FIG. 12C shows an optical system 100Z as a comparative example including another optical member 20Z, and an illumination system 200Z including the same. In the illumination system 200Z according to this comparative example, the optical member 20Z has a configuration in which both ends of the optical member 20Y according to the above comparative example in the Z-axis direction are removed to make the optical member 20Z thinner. The dimension t3 of this optical member 20Z in the Z-axis direction is the same as the dimension t1 of the optical member 20 according to this embodiment.

Furthermore, in the illumination system 200Z according to the comparative example, the optical axis Ax2 of the light source 4 is located on the normal line L21 of the main entrance surface 211. That is, in the comparative example, the optical axis Ax2 of the light source 4 is parallel to the normal L21 of the main entrance surface 211.

In such a comparative example, the chief ray L11 is located on the optical axis Ax2 of the light source 4, as shown in FIG. 12C. Further, in the Z-axis direction, a third auxiliary ray L14 and a fourth auxiliary ray L15 are located on both sides of the principal ray L11. However, the first auxiliary ray L12 and the second auxiliary ray L13 leak from the optical member 20Z and do not enter the incident surface 10 of the light guide member 1. As a result, in the illumination system 200Z according to the comparative example, light rays with relatively high intensity, including the first auxiliary light ray L12 and the second auxiliary light ray L13, do not enter the entrance surface 10 of the light guide member 1, and the light The extraction efficiency is significantly lower than in this embodiment.

As explained above, in the optical member 20 according to the present embodiment, it is possible to improve the light intake efficiency in the optical member 20 while reducing the size compared to the comparative examples shown in FIGS. 12B and 12C. can.

(2.7) Light Distribution Control Unit Next, the light distribution control unit 14 will be described in detail with reference to FIG. 3.

That is, in this embodiment, at least one of the first surface 11 and the second surface 12 includes the light distribution control section 14. The light distribution control unit 14 controls the light distribution of light extracted from the second surface 12, which is the output surface. In this embodiment, as an example, the light distribution control section 14 is provided on the second surface 12. Furthermore, in this embodiment, the light distribution control section 14 is integrated with the light guide member 1 as an integrally molded product. That is, in this embodiment, the light guide member 1 and the light distribution control section 14 are integrally molded and are inseparable from each other.

In short, in this embodiment, the light guide member 1 allows the light that enters the light guide member 1 from the incident surface 10 to pass through the second surface 12 with only one reflection at the prism 3 inside the light guide member 1. It includes a direct optical path L1 that allows the light to be emitted from the light source. Therefore, the shapes of the first surface 11 and the second surface 12 do not contribute to the light guide inside the light guide member 1, and the light distribution control section 14 is not provided on the first surface 11 or the second surface 12. Even if provided, the light guide performance of the light guide member 1 is unlikely to deteriorate.

Specifically, the light distribution control section 14 in this embodiment includes a lens. In other words, the light distribution control unit 14 has a lens function as an optical element that refracts and diverges or converges light. Thereby, the light distribution control unit 14 can control the light distribution by refracting and diverging or converging the light extracted from the second surface 12, which is the output surface.

More specifically, the light distribution control unit 14 includes a multi-lens consisting of a group of a plurality of small lenses 141. In this embodiment, each of the plurality of small lenses 141 is formed in a semi-cylindrical shape. Such a plurality of small lenses 141 are arranged side by side in the X-axis direction. Here, the plurality of small lenses 141 are formed over the entire second surface 12 without gaps. A multi-lens made up of a group of a plurality of small lenses 141 having such a shape constitutes a so-called cylindrical lens.

(3) Modifications Embodiment 1 is only one of various embodiments of the present disclosure. Embodiment 1 can be modified in various ways depending on the design, etc., as long as the objective of the present disclosure can be achieved. Each of the figures described in the first embodiment is a schematic diagram, and the size and thickness ratios of the constituent elements in the figures do not necessarily reflect the actual size ratios.

Modifications of the first embodiment will be listed below. The modified examples described below can be applied in combination with the first embodiment as appropriate.

(3.1) First Modification In the optical system 100A according to the first modification, as shown in FIGS. 13A to 13C, the inclination angle θ3 of the reflective surface 30 of the prism 3A with respect to the first surface 11 is different from that of the first embodiment. This is different from the optical system 100 according to .

That is, as shown in FIG. 13B, the inclination angle θ3 of the reflective surface 30 of the prism 3A with respect to the first surface 11 is such that when the light incident from the incident surface 10 is totally reflected toward the second surface 12 on the direct optical path L1. less than the maximum angle of In other words, the inclination angle θ3 of the reflective surface 30 of the prism 3A in this modification is smaller than the inclination angle θ1 of the reflective surface 30 of the prism 3 in the first embodiment (see FIG. 1B). This makes it difficult for the incident angle θ4 to fall below the critical angle even if the incident angle θ4 of light incident on the reflective surface 30 varies somewhat. In other words, even if the incident angle θ4 of light incident on the reflective surface 30 varies somewhat, the light incident on the reflective surface 30 is likely to be totally reflected by the reflective surface 30. As a result, the amount of light that passes through the reflective surface 30 and leaks from the light guide member 1 can be reduced, leading to an improvement in light extraction efficiency.

However, in this modification, the light beam that enters the second surface 12 on the direct optical path L1 follows an optical path that is inclined with respect to the Z axis. As a result, as shown in FIG. 13A, the light emitted from the second surface 12 is emitted not in a direction perpendicular to the second surface 12 (Z-axis direction) but obliquely with respect to the normal to the second surface 12. will be done.

Therefore, as shown in FIG. 13C, the normal L22 to the second surface 12A may be inclined with respect to the optical axis of the light that enters the second surface 12A on the direct optical path L1. In the example of FIG. 13C, the second surface 12A is not parallel to the XY plane, but is a plane inclined at an angle θ5 with respect to the XY plane. Here, the second surface 12A is inclined with respect to the XY plane so that it approaches the first surface 11 as it moves away from the entrance surface 10. Thereby, the normal L22 of the second surface 12A is inclined with respect to the optical axis of the light that enters the second surface 12A on the direct optical path L1. Therefore, the light beam incident on the second surface 12A on the direct optical path L1 is refracted at the second surface 12A and emitted in a direction perpendicular to the XY plane. That is, light that enters the second surface 12A at an incident angle θ6 is emitted from the second surface 12A at an exit angle θ7 (>θ6).

(3.2) Second Modification The optical system 100B according to the second modification has the point that the entire light control body 2B is inclined with respect to the light guide member 1, as shown in FIGS. 14A and 14B. , is different from the optical system 100 according to the first embodiment.

That is, in order to realize the configuration described in the section "(2.4) Oblique light incidence", the optical axis Ax1 of the light incident from the incident surface 10 of the light guide member 1 is It suffices if it is inclined with respect to the first surface 11 so that the distance to the first surface 11 is small. According to this modification, both sides of the light control body 2B in the thickness direction (Z-axis direction) are tilted with respect to the light guide member 1, so that the entire light control body 2B is tilted with respect to the light guide member 1. do. Even with such a configuration, it is easy to increase the proportion of the light emitted from the second surface 12 to the outside of the light guide member 1 through the direct optical path L1 to the light incident from the entrance surface 10, and the light extraction efficiency is improved. can be achieved.

In particular, in this modification, as shown in FIG. 14B, the optical axis Ax1 of the light incident from the incident surface 10 of the light guide member 1 is not only directed toward the first surface 11 but also relative to the second surface 12. It also slopes. Here, the optical axis Ax1 is inclined with respect to the second surface 12 such that the distance to the second surface 12 increases as the distance from the entrance surface 10 increases. If the optical axis Ax1 is inclined with respect to the second surface 12 in this way, as shown in FIG. 14B, it becomes more difficult for the light incident on the entrance surface 10 to reach the end surface 13. As a result, light can be efficiently emitted from the second surface 12 while suppressing light leakage from the end surface 13.

Furthermore, in this modification, as shown in FIG. 14B, the light emitted from the second surface 12 is not directed in a direction perpendicular to the second surface 12 (Z-axis direction) but in a direction normal to the second surface 12. The beam is emitted diagonally. That is, even in this modification, as in the first modification shown in FIG. 13A, the light beam incident on the second surface 12 on the direct optical path L1 follows an optical path inclined with respect to the Z axis. Therefore, the light enters the second surface 12 obliquely.

In this way, the light emitted from the second surface 12 through the direct optical path L1 is not limited to the configuration in which the light is emitted in the direction perpendicular to the second surface 12, but can be emitted at an appropriate angle with respect to the normal to the second surface 12. It may be inclined. Furthermore, the direction of the light emitted from the second surface 12 through the direct optical path L1 may or may not be uniform over the entire second surface 12. If the direction of the light emitted from the second surface 12 is not uniform over the entire second surface 12, the light will be emitted in different directions for different parts of the second surface 12.

In particular, when applying the optical system 100B including the light guide member 1 to a head-up display mounted on the moving body B1, the light distribution from the light guide member 1 is controlled according to the optical system 320, as described above. It is preferable that In other words, it is preferable to spread the light emitted from the optical system 100B to the range where it enters the optical system 320 in accordance with the optical system 320. That is, in accordance with the optical system 320, it is preferable that the viewing angle of the emitted light is narrow, that is, the directivity is high, at each location on the second surface 12, which is the emitting surface of the light guide member 1. On the other hand, it is preferable that the direction of the emitted light differs depending on the optical system 320 for each part on the second surface 12, which is the emitting surface of the light guide member 1.

However, the reason why the light emitted from the second surface 12 through the direct optical path L1 is inclined with respect to the normal line of the second surface 12 is based on the premise that the optical axis Ax1 is inclined with respect to the second surface 12. Not that I will. In other words, when the optical axis Ax1 is parallel to the second surface 12 as in the first embodiment, the light emitted from the second surface 12 through the direct optical path L1 is at an appropriate angle with respect to the normal to the second surface 12. It may be tilted. Conversely, in a configuration in which the optical axis Ax1 is inclined with respect to the second surface 12, the light emitted from the second surface 12 through the direct optical path L1 may be emitted in a direction perpendicular to the second surface 12. .

(3.3) Third Modified Example As shown in FIG. 15, the light control body 2C according to the third modified example differs from the first embodiment in that it has a symmetrical shape in the thickness direction (Z-axis direction). This is different from the optical system 100.

That is, in this modification, the surface of the light controller 2C facing the light source 4 is symmetrical in one direction (Z-axis direction) perpendicular to the axis facing the light source 4 (here, the normal L21 of the main entrance surface 211). It has a shape. That is, the entrance lens 21, which is the surface of the light control body 2C facing the light source 4, has a symmetrical shape. Specifically, the entrance lens 21 has a sub-incidence surface 212 around the entire circumference of a main entrance surface 211 . The sub-incidence surface 212 is divided into a plurality of (eight in this case) lens surfaces 201 to 208.

(3.4) Fourth Modification In the illumination system 200 using the optical system 100 according to the fourth modification, the illumination system 200 is arranged parallel to the display 5, as shown in FIGS. 16A and 16B. This is different from the lighting system 200 according to the first embodiment.

That is, in this modification, the second surface 12 of the light guide member 1, which is the output surface of the illumination system 200, is arranged parallel to the back surface of the display 5. However, in this arrangement, since the second surface 12 is inclined with respect to the horizontal plane, the light emitted straight from the second surface 12 is directed diagonally upward from the image display section 310, as shown in FIG. 16A. It will be emitted. Therefore, as shown in FIG. 16B, the shape of the light distribution control section 14 provided on the second surface 12 is changed, and the light distribution control section 14 controls the light distribution of the light emitted from the second surface 12. It is preferable to do so. That is, according to the light distribution control section 14 as shown in FIG. 16B, the light emitted from the second surface 12 is emitted upward from the image display section 310.

(3.5) Fifth Modification In the optical system 100 according to the fifth modification, as shown in FIGS. 17A and 17B, the configuration of the light distribution control section 14A (or 14B) is different from that of the optical system 100 according to the first embodiment. Different from 100.

In the example of FIG. 17A, the light distribution control unit 14A includes a lens array. The lens array referred to here is a type of multi-lens consisting of a group of multiple small lenses. In the light distribution control unit 14A, a plurality of small lenses are arranged in a matrix so that a plurality of small lenses are lined up in the vertical direction (Y-axis direction) and the horizontal direction (X-axis direction) of the second surface 12. Each of the plurality of small lenses may be a convex lens or a concave lens.

In the example of FIG. 17B, the light distribution control unit 14B includes a Fresnel lens. The Fresnel lens referred to here is a lens in which the amount of protrusion (or amount of recess) in the lens is kept small by dividing a single lens into concentric areas. Here, as an example, the light distribution control unit 14B is a Fresnel lens formed by dividing a convex lens into concentric areas around the center of the second surface 12.

(3.6) Sixth Modification In the optical system 100 according to the sixth modification, as shown in FIGS. 18A to 20B, the shapes of the prisms 3B, 3C, 3D, 3E, 3F, and 3G are the same as in the first embodiment. This is different from the optical system 100.

In the example of FIG. 18A, the plurality of prisms 3B are arranged along an arc when viewed from one side in the Z-axis direction. Here, the plurality of prisms 3B are arranged in an arc shape convex on the side opposite to the entrance surface 10. That is, in this modification, at least some of the prisms 3B are inclined with respect to the entrance surface 10 when viewed from the direction in which the first surface 11 and the second surface 12 are lined up (Z-axis direction).

In the example of FIG. 18B, the ends of the plurality of prisms 3C included in the even-numbered rows and the plurality of prisms 3C included in the odd-numbered rows in the longitudinal direction (X-axis direction) do not overlap in the Y-axis direction. It is placed in such a position. According to such an arrangement, when viewed from the entrance surface 10, the plurality of prisms 3C are lined up with a slight gap in the X-axis direction. The plurality of prisms 3C arranged in this manner may also be arranged so as to line up along an arc when viewed from one side in the Z-axis direction, similarly to the example of FIG. 18A.

In the example of FIG. 19A, each of the plurality of prisms 3D is formed in a straight line parallel to the X-axis when viewed from one side in the Z-axis direction. In the example of FIG. 19A, the plurality of prisms 3D are formed on the first surface 11 of the light guide member 1 so as to be spaced apart from each other in the Y-axis direction. That is, in the example of FIG. 19A, a plurality of prisms 3D are provided so as to be lined up in the direction in which light enters the entrance surface 10 (Y-axis direction).

In the example of FIG. 19B, each of the plurality of prisms 3E is formed in a curved shape extending in an arc shape when viewed from one side in the Z-axis direction. Here, the prism 3E is formed in an arcuate shape convex on the side opposite to the entrance surface 10. In the example of FIG. 19B, the plurality of prisms 3E are formed on the first surface 11 of the light guide member 1 so as to be spaced apart from each other in the Y-axis direction. That is, in the example of FIG. 19B, a plurality of prisms 3E are provided so as to be lined up in the direction in which light enters the entrance surface 10 (Y-axis direction).

In the example of FIG. 20A, the ends of the plurality of prisms 3F included in the even-numbered columns and the plurality of prisms 3F included in the odd-numbered columns in the longitudinal direction (X-axis direction) do not overlap in the Y-axis direction. It is placed in such a position. Moreover, the plurality of prisms 3F are arranged in a free curved line when viewed from one side in the Z-axis direction. The "free curve" here includes various free curves such as a C-shape, a U-shape, a J-shape, or an S-shape. Here, the plurality of prisms 3F are arranged in a free curve shape convex on the side opposite to the entrance surface 10. That is, in this modification, at least some of the prisms 3F are inclined with respect to the entrance surface 10 when viewed from the direction in which the first surface 11 and the second surface 12 are lined up (Z-axis direction).

In the example of FIG. 20B as well, similarly to the example of FIG. 20A, the plurality of prisms 3G are arranged in a free curved line when viewed from one side in the Z-axis direction. Here, the plurality of prisms 3G are arranged in a free curve shape convex toward the entrance surface 10 side. That is, in this modification, at least some of the prisms 3G are inclined with respect to the entrance surface 10 when viewed from the direction in which the first surface 11 and the second surface 12 are lined up (Z-axis direction).

By the way, in order to realize a narrow viewing angle in the optical system, it is preferable that the optical path of the light emitted from the second surface 12 be as perpendicular to the second surface 12 as possible. Here, the light emitted from the light source 4 has a spread angle narrowed by the light control body 2. However, in the XY plane, not all of the light incident on the entrance surface 10 follows an optical path perpendicular to the entrance surface 10, and some light follows an optical path that spreads in the X-axis direction. Therefore, if the prism 3 is linear parallel to the X-axis, a portion of the light incident on the incident surface 10 will be obliquely incident on the reflective surface 30 of the prism 3 in the XY plane. In this case, the light totally reflected by the reflective surface 30 of the prism 3 follows an optical path at an angle to the second surface 12, rather than an optical path perpendicular to the second surface 12, resulting in a narrow viewing angle. This may become difficult to achieve.

On the other hand, in the modified examples shown in FIGS. 18A, 19B, 20A, and 20B, at least some of the prisms 3B, 3E, 3F, and 3G are inclined with respect to the entrance surface 10 when viewed from the Z-axis direction. That is, in this modification, the light incident on the entrance surface 10 tends to be incident perpendicularly to the reflective surfaces 30 of the prisms 3B, 3E, 3F, and 3G in the XY plane. Therefore, in these modified examples, the light totally reflected by the reflective surfaces 30 of the prisms 3B, 3E, 3F, and 3G tends to follow an optical path perpendicular to the second surface 12, resulting in a narrow viewing angle. It has the advantage of being easy to do.

Further, in the modification shown in FIG. 18A, the plurality of prisms 3B may be arranged in an arc shape convex toward the entrance surface 10 side. In the modification shown in FIG. 19B, the prism 3E may be formed in an arcuate shape convex toward the entrance surface 10 side. Furthermore, as shown in FIGS. 20A and 20B, the plurality of prisms 3F and 3G arranged in a free curve when viewed from one side in the Z-axis direction may have a continuous shape in the longitudinal direction as shown in FIG. 19B. good.

(3.7) Seventh Modification In the optical system 100 according to the seventh modification, as shown in FIGS. 21A to 21C, the cross-sectional shapes of the prisms 3H, 3I, and 3J are different from the optical system 100 according to the first embodiment. differ. 21A to 21C are schematic diagrams corresponding to FIG. 1B, which are enlarged views of essential parts of the optical system 100 (area A1 in FIG. 1A).

In the example of FIG. 21A, the reflective surface 30 of the prism 3H is formed not in a flat shape but in a curved shape. In the example of FIG. 21A, the reflective surface 30 of the prism 3H is a convex curved surface that is curved to be convex on the side opposite to the second surface 12, that is, the side opposite to the incident surface 10, when viewed from one side in the X-axis direction. It is. Here, the reflective surface 30 of the prism 3H is curved only in a cross section parallel to the YZ plane, that is, a cross section perpendicular to the X axis, and curved only in a cross section parallel to the XY plane, that is, perpendicular to the Z axis. It is straight in cross section. However, the reflective surface 30 of the prism 3H is not limited to the example of FIG. 21A, and is a concave curved surface that is convex toward the second surface 12 side, that is, toward the incident surface 10 side when viewed from one side in the X-axis direction. You can. Further, the reflective surface 30 of the prism 3H may be curved only in a cross section parallel to the XY plane, that is, a cross section orthogonal to the Z axis, or may be curved only in a cross section parallel to the YZ plane and parallel to the XY plane. It may be curved in both cross sections.

Moreover, in the example of FIG. 21B, the reflective surface 30 of the prism 3I is formed not in a plane but in a polygonal shape. The "polygonal surface" here is a so-called curved surface, which is a surface formed by combining a plurality of planes with different orientations, like the surface of a part of a polyhedron. In the example of FIG. 21B, the reflective surface 30 of the prism 3I is a polygonal surface bent so as to be convex on the side opposite to the second surface 12, that is, the side opposite to the incident surface 10 when viewed from one side in the X-axis direction. (convex). Here, the reflective surface 30 of the prism 3I is bent only in a cross section parallel to the YZ plane, that is, a cross section perpendicular to the X axis, and only in a cross section parallel to the XY plane, that is, perpendicular to the Z axis. It is straight in cross section. However, the reflective surface 30 of the prism 3I is not limited to the example of FIG. 21B, and the reflective surface 30 of the prism 3I is a polygonal surface (a concave ). Further, the reflective surface 30 of the prism 3I may be bent only in a cross section parallel to the XY plane, that is, a cross section orthogonal to the Z axis, or may be bent only in a cross section parallel to the YZ plane and parallel to the XY plane. It may be bent in both cross sections.

Furthermore, in the example of FIG. 21C, the side surface 31 of the prism 3J is not flat but curved. The side surface 31 is a surface of the inner surface of the prism 3J that intersects with the reflective surface 30, that is, a surface opposite to the incident surface 10 when viewed from the reflective surface 30. In the example of FIG. 21C, the side surface 31 of the prism 3J is a concave curved surface that is convex toward the side opposite to the reflective surface 30, that is, the side opposite to the incident surface 10, when viewed from one side in the X-axis direction. . Here, the side surface 31 of the prism 3J is curved only in a cross section parallel to the YZ plane, that is, a cross section perpendicular to the X axis, and curved only in a cross section parallel to the XY plane, that is, a cross section perpendicular to the Z axis. It becomes a straight line. However, the side surface 31 of the prism 3J is not limited to the example shown in FIG. good. Furthermore, the side surface 31 of the prism 3J may be curved only in a cross section parallel to the XY plane, that is, a cross section orthogonal to the Z axis, or may be curved only in a cross section parallel to the YZ plane and in a cross section parallel to the XY plane. It may also be curved in both cross sections.

Further, the side surface 31 of the prism 3J is not limited to a curved shape, and may be formed in a polygonal shape similar to the reflective surface 30 of the prism 3I in FIG. 21B. In this case, as in the case of a curved surface, the side surface 31 of the prism 3J may be a polygonal surface (concave surface) bent so as to be convex on the side opposite to the reflective surface 30 when viewed from one side in the X-axis direction. Alternatively, it may be a polygonal surface (convex surface) bent so as to be convex toward the reflective surface 30 side.

As in this modification, the prism 3 is not limited to having a triangular cross section when viewed from one side in the X-axis direction, but may have an appropriate shape. Furthermore, the cross-sectional shapes of the prisms 3H, 3I, and 3J described above may be employed in combination with each other, or in combination with the shapes of the prisms 3B, 3C, 3D, 3E, 3F, and 3G described in the sixth modification. Good too.

If the reflective surface 30 is curved or polygonal, the distribution of light reflected by the prism 3 (reflective surface 30) and emitted from the second surface 12, specifically, the spread angle or The direction etc. can be controlled by the reflective surface 30. Therefore, depending on the shape of the prism 3 (reflecting surface 30), it is possible to match the light distribution of the light emitted from the second surface 12 to the optical characteristics of the display 5, the optical system 320, etc., for example. In addition, by adopting an appropriate shape such as a curved surface or a polygonal surface for at least one of the reflective surface 30 and the side surface 31, mold releasability can be improved during molding (manufacturing process) of the light guide member 1, for example. It is also possible to improve production efficiency by

(3.8) Other modifications The first surface 11 is a surface perpendicular to the entrance surface 10, and the second surface 12 is not perpendicular to the entrance surface 10 but is inclined with respect to the XY plane. Good too. Furthermore, 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.

Furthermore, the plurality of prisms 3 may not all have the same shape. For example, the plurality of prisms 3 may have different inclination angles θ1 of the reflective surfaces 30, longitudinal dimensions of the prisms 3, depths of recesses as the prisms 3 (in other words, heights of the prisms 3), etc. The prism 3 may include various types of prisms 3. In particular, in the display system 300 as a head-up display, the intensity of light emitted from the second surface 12, which is the exit surface of the light guide member 1, is made uniform in order to make the brightness of the displayed virtual image uniform. It is preferable. In this case, if the intensity distribution (strictly speaking, illuminance distribution) of the light on the first surface 11 is not uniform, the shape of the prism 3 can be made different for each part of the first surface 11 so that the light can be emitted from the second surface 12. It is preferable to make the intensity of the emitted light uniform. In this way, the plurality of prisms 3 may have different shapes for each portion of the first surface 11.

Further, the light guide member 1 only needs to include the direct optical path L1, and it is not essential that all of the light incident from the entrance surface 10 passes through the direct optical path L1. That is, the light guide member 1 includes, for example, an indirect optical path in which the light is reflected at least once on the first surface 11 or the second surface 12, and then reflected on the prism 3 and emitted from the second surface 12. Good too.

Further, only one prism 3 may be provided on the first surface 11 instead of a plurality of prisms 3. In this case, the prism 3 may have a plurality of reflective surfaces 30 formed over the entire first surface 11 and having different inclination angles.

Further, in the first embodiment, the prism 3 is formed by processing the first surface 11 of the light guide member 1, but the prism 3 is not limited to this aspect. For example, the prisms 3 may be provided on the first surface 11 by pasting a prism sheet on which the prisms 3 are formed. In this case, one prism 3 may be formed on the prism sheet, or a plurality of prisms 3 may be formed on the prism sheet.

Further, the prism 3 is not limited to a concave shape with respect to the first surface 11, that is, a shape that is depressed from the first surface 11, but a convex shape with respect to the first surface 11, that is, a shape that protrudes from the first surface 11. You can. Even if the prism 3 has a convex shape with respect to the first surface 11, various shapes can be adopted as illustrated in the sixth modification and the seventh modification.

Further, the light distribution control unit 14 only needs to control the light distribution of the light extracted from the second surface 12 and may be provided on at least one of the first surface 11 and the second surface 12. That is, in the first embodiment, the light distribution control section 14 is provided on the second surface 12 as the output surface, but the structure is not limited to this, and the light distribution control section 14 may be provided on the first surface 11. Alternatively, it may be provided on both the first surface 11 and the second surface 12. Furthermore, in the first embodiment, the light distribution control section 14 is integrated with the light guide member 1 as an integrally molded product, but the present invention is not limited to this embodiment. For example, the light distribution control section 14 may be provided on the second surface 12 by attaching a light distribution sheet on which the light distribution control section 14 is formed to the second surface 12 .

Further, the light distribution control section 14 is not limited to a lens, and may be, for example, a diffusion sheet, a prism, a diffraction grating, or the like.

Further, the mobile body B1 on which the display system 300 is mounted is not limited to a car (passenger car), but may also be a large vehicle such as a truck or a bus, a motorcycle, a train, an electric cart, a construction machine, an aircraft, a ship, etc. good.

Further, the display system 300 is not limited to a configuration that displays a virtual image like a head-up display. For example, display system 300 may be a liquid crystal display or a projector device. Further, the display system 300 may be a car navigation system, an electronic mirror system, or a multi-information display mounted on the mobile body B11.

Furthermore, the lighting system 200 is not limited to the configuration used in the display system 300, and may be used for, for example, industrial applications such as resin curing or plant cultivation, or lighting applications including guide lights.

Further, the light control body 2 is not an essential component of the optical system 100 and may be omitted. That is, the optical system 100 only needs to include the light guide member 1 and the prism 3, and the light controller 2 can be omitted as appropriate.

(Embodiment 2)
The optical system 100C according to the present embodiment differs from the optical system 100 according to the first embodiment in that it includes a plurality of types of prisms 301 and 302 having mutually different shapes, as shown in FIGS. 22A to 22D. Hereinafter, configurations similar to those in Embodiment 1 will be given the same reference numerals and descriptions will be omitted as appropriate.

That is, in this embodiment, a plurality of prisms 301 and 302 are provided so as to be lined up in the direction in which light enters the entrance surface 10 (Y-axis direction). The plurality of prisms 301 and 302 include a first prism 301 and a second prism 302. The first prism 301 and the second prism 302 have different inclination angles θ11 and θ12 of the reflective surface 30 with respect to the first surface 11. Specifically, the reflective surface 30 of the first prism 301 is inclined with respect to the first surface 11 at an inclination angle θ11, and the reflective surface 30 of the second prism 302 is inclined with respect to the first surface 11 at an inclination angle θ12. . The inclination angle θ11 is larger than the inclination angle θ12. In other words, the first prism 301 has a larger inclination angle of the reflective surface 30 with respect to the first surface 11 than the second prism 302 .

Here, the first surface 11 includes a first region Z1 and a second region Z3. The first area Z1 is an area where a plurality of first prisms 301 are arranged. The second area Z3 is an area where a plurality of second prisms 302 are arranged. That is, the first prism 301 and the second prism 302, which have different shapes from each other, are basically arranged separately in a first region Z1 and a second region Z3. In the first region Z1, as shown in FIG. 22B, a plurality of first prisms 301 are arranged side by side. On the other hand, in the second region Z3, as shown in FIG. 22D, a plurality of second prisms 302 are arranged side by side.

Moreover, the first surface 11 further includes a mixed region Z2 between the first region Z1 and the second region Z3. The mixed area Z2 is an area where both the first prism 301 and the second prism 302 are mixed. That is, in the mixed area Z2, as shown in FIG. 22C, the first prism 301 and the second prism 302 are mixed.

"Mixed" as used in this disclosure means to exist in a mixed manner. In other words, in the mixed region Z2, the second prism 302 exists between the first prisms 301 and 301, or the first prism 301 exists between the second prisms 302 and the second prisms 302. do. In this way, in the mixed region Z2, the first prism 301 and the second prism 302 exist in a mixed manner. Due to the existence of such a mixed region Z2, near the boundary between the first prism 301 and the second prism 302, there is a region where the first prism 301 exists (first region Z1) and a region where the second prism 302 exists. (Second region Z3) is not completely divided into two.

Furthermore, the mixed area Z2 includes a first mixed area Z21 and a second mixed area Z22. The first mixed area Z21 is located on the first area Z1 side when viewed from the intermediate position C10 between the first area Z1 and the second area Z3. The second mixed area Z22 is located on the second area Z3 side when viewed from the intermediate position C10. In the first mixed region Z21, the density of the first prisms 301 is higher than in the second mixed region Z22.

Specifically, as shown in FIG. 22A, the first surface 11 is divided into a first region Z1, a mixed region Z2, and a second region Z3 in the Y-axis direction. The first region Z1, the mixed region Z2, and the second region Z3 are arranged in this order from the light control body 2 side (the incident surface 10 side): the first region Z1, the mixed region Z2, and the second region Z3. The mixed region Z2 is divided into a first mixed region Z21 and a second mixed region Z22 at an intermediate position C10 in the Y-axis direction. The first mixed region Z21 and the second mixed region Z22 are arranged in the order of the first mixed region Z21 and the second mixed region Z22 from the light control body 2 side (the incident surface 10 side).

In the first mixed region Z21, the first prisms 301 are arranged more densely than in the second mixed region Z22. As an example, assume that a plurality of prisms 301 and 302 are arranged at equal pitches. In this case, in the second mixed area Z22, the ratio of the second prism 302 to the first prism 301 is 2:1, whereas in the first mixed area Z21, the ratio of the second prism 302 to the first prism 301 is 2:1. The ratio is 1:2.

Further, as a modification of the second embodiment, the plurality of prisms 301 and 302 may further include a third prism in addition to the first prism 301 and the second prism 302. That is, the plurality of prisms 301 and 302 may include three or more types of prisms 301 and 302 in which the inclination angles θ11 and θ12 of the reflective surface 30 with respect to the first surface 11 are different from each other.

The various configurations (including modified examples) described in Embodiment 2 can be employed in appropriate combination with the various configurations (including modified examples) described in Embodiment 1.

(summary)
As described above, the optical system (100, 100A to 100C) according to the first aspect includes the light guide member (1) and the prism (3, 3A to 3J). The light guide member (1) has an entrance surface (10) through which light enters, and a first surface (11) and a second surface (12, 12A) that face each other. The second surface (12, 12A) of the light guide member (1) is a light exit surface. The prisms (3, 3A to 3J) are provided on the first surface (11) and reflect light passing through the interior of the light guide member (1) toward the second surface (12, 12A). The light guide member (1) includes a direct optical path (L1) that directly reflects the light incident from the incident surface (10) on the prism (3, 3A to 3J) and outputs it from the second surface (12, 12A). . The optical axis (Ax1) of the light incident from the entrance surface (10) is inclined with respect to the first surface (11) so that the distance to the first surface (11) decreases as the distance from the entrance surface (10) increases. are doing.

According to this aspect, the light incident from the entrance surface (10) approaches the first surface (11) as it moves away from the entrance surface (10), that is, as it travels inside the light guide member (1). , it is easy to enter the prism (3, 3A to 3J). Therefore, most of the light incident from the entrance surface (10) becomes difficult to reach the end surface of the light guide member (1) on the opposite side to the entrance surface (10), so that light is difficult to leak from the end surface. As a result, it is easy to increase the proportion of the light emitted from the second surface (12, 12A) to the outside of the light guide member (1) through the direct optical path (L1) to the light incident from the entrance surface (10), and the light The extraction efficiency can be improved.

The optical system (100, 100A to 100C) according to the second aspect further includes a light control body (2, 2B, 2C) in the first aspect. The light control body (2, 2B, 2C) is located between the light source (4) and the entrance surface (10), and controls the light that is output from the light source (4) and enters the entrance surface (10).

According to this aspect, by controlling the light incident on the incident surface (10) with the light control body (2, 2B, 2C), it is possible to further improve the light extraction efficiency.

In the optical system (100, 100A to 100C) according to the third aspect, in the second aspect, the light controller (2, 2B, 2C) is a collimator that brings the light output from the light source (4) closer to parallel light. Has a function.

According to this aspect, the light incident on the entrance surface (10) can be brought closer to parallel light, so that the light extraction efficiency can be further improved.

In the optical system (100, 100A to 100C) according to the fourth aspect, in the second or third aspect, the light control body (2, 2B, 2C) is integrated with the light guide member (1). The light control body (2, 2B, 2C) has a path generation section (23). The path generation unit (23) extends along a straight line inclined with respect to the first surface (11) when viewed from the entrance surface (10), and transmits light between the light source (4) and the entrance surface (10). form a route.

According to this aspect, since the light from the light source (4) enters the entrance surface (10) through the inside of the path generation section (23), the light from the light source (4) until reaching the entrance surface (10) is Loss can be reduced.

In the optical system (100, 100A to 100C) according to the fifth aspect, in any of the first to fourth aspects, all the light that reaches the second surface (12, 12A) on the direct optical path (L1) is The light is incident on the two surfaces (12, 12A) at the same angle.

According to this aspect, the direction of the light emitted from the second surface (12, 12A) can be aligned.

In the optical system (100, 100A to 100C) according to the sixth aspect, in any of the first to fifth aspects, the light emitted from the second surface (12, 12A) in the direct optical path (L1) is This is 50% or more of the light that enters the light guide member (1) from the surface (10).

According to this aspect, the light extraction efficiency can be significantly improved.

An illumination system (200) according to a seventh aspect includes an optical system (100, 100A to 100C) according to any one of the first to sixth aspects, and a light source (4) that outputs light incident on an incident surface (10). ) and.

According to this aspect, it is possible to improve the light extraction efficiency.

A display system (300) according to an eighth aspect includes: an illumination system (200) according to the seventh aspect; a display device (5) that receives light emitted from the illumination system (200) and displays an image; Equipped with

According to this aspect, it is possible to improve the light extraction efficiency.

The mobile body (B1) according to the ninth aspect includes the display system (300) according to the eighth aspect and a mobile body main body (B11) on which the display system (300) is mounted.

According to this aspect, it is possible to improve the light extraction efficiency.

The configurations according to the second to sixth aspects are not essential to the optical system (100, 100A to 100C) and can be omitted as appropriate.

1 Light guide member 2, 2B, 2C Light controller 3, 3A to 3J Prism 4 Light source 5 Display 10 Incident surface 11 First surface 12, 12A Second surface 23 Path generation unit 100, 100A to 100C Optical system 200 Illumination system 300 Display system Ax1 Optical axis Ax2 Optical axis B1 Moving body B11 Moving body main body L1 Direct optical path

Claims (7)

a light guide member having an entrance surface into which light from a light source enters, and a first surface and a second surface facing each other, the second surface being a light exit surface;
a prism provided on the first surface and reflecting light passing through the interior of the light guide member toward the second surface;
a light control body located between a light source and the incident surface and controlling light output from the light source and incident on the incident surface,
The light guide member includes a direct optical path in which the light incident from the incident surface is directly reflected by the prism and exits from the second surface,
The optical axis of the light incident from the incident surface is inclined with respect to the first surface such that the distance to the first surface decreases as the distance from the incident surface increases;
The light control body is integrated with the light guide member,
The light control body includes a path generating section that extends along a straight line inclined with respect to the first surface when viewed from the incident surface, and forms a light path between the light source and the incident surface. death ,
The light control body includes an entrance lens,
The optical axis of the light source is inclined toward the first surface with respect to the optical axis of the incident surface,
The entrance lens is
a main incidence surface arranged to face the light source;
a sub-incident surface located on at least a portion of the periphery of the main-incident surface and oriented in the normal line of the main-incident surface;
The entrance lens has the sub-incidence surface on the first surface side and is open on the second surface side.
optical system. The light controller has a collimating function that brings the light output from the light source closer to parallel light.
Optical system according to claim 1. All the light that reaches the second surface in the direct optical path is incident on the second surface at the same angle.
The optical system according to claim 1 or 2. The light emitted from the second surface in the direct optical path is 50% or more of the light that enters the light guide member from the incident surface.
Optical system according to any one of claims 1 to 3. The optical system according to any one of claims 1 to 4,
the light source outputting light incident on the incident surface;
lighting system. A lighting system according to claim 5,
a display that receives light emitted from the illumination system and displays an image;
display system. The display system according to claim 6,
a mobile body body equipped with the display system;
mobile object.

Images