Vehicle-mounted information display device and system with solid light source

Abstract

The present invention provides an in-vehicle information display device and system having a solid-state light source, the in-vehicle information display device having a virtual image-type image display device including an optical system including an image display device that displays an image, and a light source that supplies light to the image display device. A light source device having a surface-emitting solid light source; and an optical module for receiving image light from the image display device. The light source device comprises a light source unit, an optical film and an image display device, wherein the light source unit is formed by two-dimensionally arranging a plurality of single light source modules. A single light source module is formed by exciting a yellow phosphor containing green and red light by blue light of a blue solid light source, mixing the yellow phosphor with the blue light to obtain a white surface light-emitting solid light source emitting white light, and an optical element capable of reducing the divergence angle of a light beam diverged by the white surface light-emitting solid light source. The present invention improves the performance of an optical assembly by considering the diffusion characteristics of image light emitted by an image display device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of projecting images on the front windshield or combination screen of a vehicle, such as a car, train, airplane, etc. (hereinafter collectively referred to as "vehicle"), and in particular to a vehicle-mounted information display device and system having a solid light source. BACKGROUND

[0002] Known vehicle-mounted information display systems (Head-Up Display Device) enlarge the image of an image source by a concave mirror and provide the image to the driver through the front windshield. The light emitted by the image source used in the information display device is completely diffused light, and in order to sufficiently ensure the brightness of the enlarged image in the projection optical system with the concave mirror, a large concave mirror is required to capture the image light beam diffused over a large area.

[0003] In the optical system that uses a concave mirror to enlarge the image displayed by the image source and obtain a virtual image, conventional image sources, such as organic EL (Electric Luminescent), emit image light that is completely diffused, and thus a large-diameter concave mirror is required to capture all of the image light. In addition, in order to achieve a large diameter and good focusing performance of the virtual image optical assembly with the concave mirror, multiple concave mirrors or a combination with lens elements are required.

[0004] However, in the design of the optical assembly that uses the above-mentioned conventional technology to obtain a virtual image enlarged image using a concave mirror, the diffusion characteristics and directional characteristics of the image light emitted by the image source, as well as the construction and implementation technology of the optimal optical system including these characteristics, are not considered. SUMMARY

[0005] To solve the above problems, the present application aims to provide an optical assembly structure and its implementation technology that can improve the utilization efficiency of light. In this optical assembly that uses a concave mirror to obtain an enlarged virtual image, the utilization efficiency of light is improved by optimizing the emission direction and diffusion characteristics of the image light emitted by the image source, without increasing the diameter of the optical assembly or the number of lenses.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a vehicle-mounted information display device and system having a solid light source, having a virtual image mode image display device, the virtual image mode image display device having an optical system, the optical system including an image display device that displays an image, a light source device having a surface-emitting solid light source that provides light for the image display device, and an optical assembly for receiving image light from the image display device;

[0007] The aforementioned light source device has a light source unit composed of a plurality of single light source modules arranged two-dimensionally, an optical film, and an image display device. The single light source module is composed of a blue light of a blue solid light source, a yellow phosphor containing green and red light, a white surface-emitting solid light source which emits white light by mixing the blue light and the yellow light, and an optical element which can reduce the divergence angle of the light beam emitted by the white surface-emitting solid light source;

[0008] The aforementioned image display device receives the white light beam emitted by the aforementioned light source unit, and adjusts the intensity of the light according to the image signal to display an image on the screen.

[0009] The aforementioned light source module is provided with a cylindrical hole near the focal point of the end surface of the reflective optical element, and the white surface-emitting solid light source is installed in the hole. The optical film is placed between the light source unit and the aforementioned image display device.

[0010] The cylindrical lens is designed on the surface of the aforementioned optical film on the side of the image display device, and the reflective polarizer is attached to the other surface.

[0011] Further, the aforementioned light source device provides light to the aforementioned image display device. The light source device has a light source unit composed of a plurality of single light source modules arranged two-dimensionally. The end surface of the single light source module is provided with a hole, and the hole has an approximate cylindrical shape along the direction of the optical axis containing the focal point of the reflective optical element. A part of the divergent light emitted by the surface-emitting solid light source is refracted by the cylindrical side surface.

[0012] The aforementioned reflective optical element of the aforementioned single light source module can reflect the divergent light beam emitted by the aforementioned surface-emitting solid light source by reflecting the light at different positions of the reflective surface, and convert the divergent light beam into a divergent light beam with a narrow angle.

[0013] The aforementioned light source device has a light source unit composed of a plurality of single light source modules arranged two-dimensionally. The end surface of the single light source module is provided with a hole, and the hole has an approximate cylindrical shape along the direction of the optical axis containing the focal point of the reflective optical element. A part of the divergent light emitted by the surface-emitting solid light source is refracted by the cylindrical side surface.

[0014] The hole designed on the end surface of the single light source module has an approximate cylindrical shape along the optical axis containing the focal point of the reflective optical element. A part of the divergent light emitted by the surface-emitting solid light source is refracted by the cylindrical side surface.

[0015] The divergent light beam emitted by the surface-emitting solid light source is reflected by the reflective surface of the aforementioned reflective optical element at different positions, and is diverged along the optical axis of the reflective optical element through multiple focal points, and is converted into a divergent light beam with a narrow angle.

[0016] The aforementioned single light source module is not provided with a shape for generating diffused light, but emits a light beam in the form of approximately parallel light through the reflective optical element, and the S-polarized light beam among the incident light source light is reflected by the reflective polarizing plate; the fluorescent material of the white solid light source element is returned and excited by the fluorescent material through the reflection on the reflection surface of the reflective optical element.

[0017] The aforementioned light source device has a light source unit composed of a plurality of single light source modules arranged two-dimensionally, an optical film, and an image display device;

[0018] The single light source module is composed of a yellow fluorescent material containing green and red light excited by the blue light of a blue solid light source, a white surface-emitting solid light source emitting white light obtained by mixing the blue light, and an optical element capable of reducing the divergence angle of the light beam emitted by the white surface-emitting solid light source;

[0019] The aforementioned image display device is configured to cause the white light beam emitted from the aforementioned light source unit to be incident on the image display device, and to adjust the intensity of the light according to an image signal to display an image on a screen;

[0020] The aforementioned light source module is provided with a cylindrical hole near the focal point of the end surface of the reflective optical element, for reflecting the light beam emitted by the white surface-emitting solid light source into approximately parallel light through the reflection surface, and the white surface-emitting solid light source is installed in the aforementioned hole;

[0021] The aforementioned optical film is installed between the aforementioned light source unit and the aforementioned image display device, the pitch of the cylindrical lenses designed on the side of the image display device of the aforementioned optical film is selected to be a value other than an integer multiple of the pixel pitch of the image display device, and a reflective polarizing plate is attached to the side of the light source unit.

[0022] The pitch of the cylindrical lenses designed on the side of the image display device of the aforementioned optical film is selected to be a value other than an integer multiple of the pixel pitch of the image display device, and is within the range of 100 micrometers to 200 micrometers.

[0023] The aforementioned virtual image type image display device has an optical system,

[0024] The aforementioned optical system includes an image display device for displaying an image, a light source device having a surface-emitting solid light source for providing light to the aforementioned image display device, and an optical assembly for receiving image light from the aforementioned image display device;

[0025] The aforementioned light source device has a light source unit composed of a plurality of single light source modules arranged two-dimensionally, an optical film, and an image display device;

[0026] The single light source module is composed of a white surface light emitting solid light source which obtains white light by exciting a yellow fluorescent body containing green and red light with blue solid light source light and mixing the blue light, and an optical element which narrows the divergence angle of the divergent light beam of the white surface light emitting solid light source;

[0027] The aforementioned image display device is characterized in that a white light beam emitted from a light source unit is incident on the image display device, and the intensity of the light is adjusted according to an image signal to display an image on a screen.

[0028] The aforementioned light source module is characterized in that a cylindrical hole is designed near the focal point of the end surface of the reflective optical element to reflect the divergent light beam of the white surface light emitting solid light source into almost parallel light by the reflecting surface, and the white surface light emitting solid light source is installed in the hole.

[0029] The aforementioned optical film is characterized in that the light source light of a specific polarization direction is selectively incident on the cylindrical lens designed on the image display device side of the optical film, and the image display device side of the optical film is attached to the reflective polarizer.

[0030] The aforementioned optical film is characterized in that the lens corresponding to the long axis direction of the cylindrical lens designed on the image display device side of the optical film has an inclination angle with respect to the pixel of the image display device.

[0031] The aforementioned optical film is characterized in that the inclination angle of the lens corresponding to the long axis direction of the cylindrical lens designed on the image display device side of the optical film with respect to the pixel of the image display device is 5 degrees or more.

[0032] The aforementioned optical film is characterized in that the light source light of a specific polarization direction is selectively incident on the cylindrical lens designed on the image display device side of the optical film, and the image display device side of the optical film is attached to the reflective polarizer.

[0033] The aforementioned optical film is characterized in that the light source light of a specific polarization direction is selectively incident on the cylindrical lens designed on the image display device side of the optical film, and the image display device side of the optical film is attached to the reflective polarizer.

[0034] The light source device is characterized in that the light source unit is composed of a plurality of single light source modules arranged in two dimensions, and the single light source module is formed of a heat-resistant plastic material.

[0035] The light source device is characterized in that the single light source module uses a heat-resistant plastic material with a heat-resistant temperature of 120 degrees or more.

[0036] Compared with the prior art, the present application has the following advantages: in a virtual image type image display device, an optical system is provided, which includes a display panel for displaying an image, a light source device for providing light to the display panel, an optical assembly for receiving image light emitted from the display panel, and a light source device for controlling the emission direction of the image light entering the optical assembly. The diffusion characteristics of the light emitted by the light source to the viewer through the display screen are controlled by the light source unit designed inside the light source device and the optical film designed between the light source unit and the display screen, so as to control the diffusion characteristics and emission direction of the image light from the liquid crystal screen. In this way, the emission direction of the image light whose light intensity is modulated according to the image signal of the image display device can be controlled, and the incident position and incident angle of the incident image light entering the rear optical assembly can also be controlled. Therefore, in this optical system, the efficiency of the image light entering the optical assembly can be improved by controlling the intensity and diffusion characteristics of the image light emitted by the image display panel as the display panel of the image display device, and an enlarged projected image can be formed. According to the present application, as the light source device of the image display device, by controlling the pointing characteristics and diffusion characteristics of the image light, in the design of the optical assembly using a concave mirror to obtain an enlarged virtual image, the performance of the optical assembly can be improved by considering the diffusion characteristics of the image light emitted by the image display device, and a high-performance optical assembly can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a schematic structural diagram of an information image device and its peripheral equipment related to an embodiment of the present application;

[0038] Figure 2 is a schematic structural diagram of an information display device, a front windshield and a driver's eye point position related to an embodiment of the present application;

[0039] Figure 3 is a schematic structural diagram of an information display device, a front windshield and a driver's eye point position related to another embodiment of the present application;

[0040] Figure 4A is a top view of a car equipped with an information display device;

[0041] Figure 4B is a diagram illustrating the difference in the radius of curvature of a front windshield;

[0042] Figure 5 is a characteristic diagram illustrating the diffusion characteristics of a surface-emitting LED light source;

[0043] Figure 6 is a first characteristic diagram of the light emission characteristics of a general white surface-emitting LED;

[0044] Figure 7 is a second characteristic diagram of the light emission characteristics of a general white surface-emitting LED;

[0045] Figure 8 A schematic diagram illustrating the general shape of the white surface light emitting LED according to the embodiment of the present application;

[0046] Figure 9 A schematic diagram illustrating the internal structure of the general white surface light emitting LED;

[0047] Figure 10 A schematic diagram illustrating the general shape of the light source optical assembly of the image display device according to the embodiment of the present application;

[0048] Figure 11 A schematic diagram illustrating the intensity variation characteristics of the refractive index of the light rays of the main components of the light source optical assembly of the image display device according to the embodiment of the present application along the optical axis;

[0049] Figure 12 A schematic diagram illustrating the cross section of the light rays tracing results of the LED light source and the main components of the light source optical assembly of the image display device according to the embodiment of the present application;

[0050] Figure 13 A schematic diagram illustrating the cross section of the divergent light state of the partial main components and the LED light source of the light source optical assembly of the image display device according to the embodiment of the present application;

[0051] Figure 14 A schematic diagram illustrating the cross section of the main component structure of the light source optical assembly of the image display device according to the embodiment of the present application;

[0052] Figure 15 A schematic diagram illustrating the general plane of the main component structure of the light source optical assembly of the image display device according to the embodiment of the present application;

[0053] Figure 16 A schematic diagram illustrating the cross section of the image display device according to the embodiment of the present application;

[0054] Figure 17 A schematic diagram illustrating the shape of the optical components of the light source optical assembly of the image display device according to the embodiment of the present application;

[0055] Figure 18 A transmittance characteristic diagram of the emission type polarizing plate according to the embodiment of the present application at an incident angle of 10 degrees ± 10 degrees;

[0056] Figure 19 A transmittance characteristic diagram of the emission type polarizing plate according to the embodiment of the present application at an incident angle of 50 degrees ± 10 degrees;

[0057] Figure 20 A conceptual cross section diagram illustrating the function of the optical components of the conventional light source device;

[0058] Figure 21 A conceptual cross section diagram illustrating the function of the optical components of the other conventional light source device;

[0059] Figure 22 FIG. 1 is a diagram illustrating a diffusion characteristic of a light source device according to an embodiment of the present application;

[0060] Figure 23A FIG. 2 is a diagram illustrating a coordinate system for testing a visual characteristic of a liquid crystal panel as an image source according to an embodiment of the present application;

[0061] Figure 23B FIG. 3 is a diagram illustrating a coordinate system for testing a visual characteristic of a liquid crystal panel as an image source according to an embodiment of the present application;

[0062] Figure 24A FIG. 4 is a diagram illustrating a coordinate system for testing a visual characteristic of a liquid crystal panel as an image source according to an embodiment of the present application;

[0063] Figure 24B FIG. 5 is a diagram illustrating a coordinate system for testing a visual characteristic of a liquid crystal panel as an image source according to an embodiment of the present application;

[0064] Figure 25 FIG. 6 is a diagram illustrating a principle of a virtual image optical system using a concave mirror according to an embodiment of the present application;

[0065] Figure 26 FIG. 7 is a diagram illustrating a light diffusion invariant;

[0066] Figure 27A FIG. 8 is a diagram illustrating a configuration of an optical assembly according to an embodiment of the present application and a design environment of an optical assembly including a concave mirror;

[0067] Figure 27B FIG. 9 is a diagram illustrating a change in an amount of stigmation generated by a projection lens constituting an optical assembly according to an embodiment of the present application or an optical assembly including a concave lens, with respect to a diffusion characteristic of image light. DETAILED DESCRIPTION

[0068] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, the present application is not limited to the embodiments described below (hereinafter, also referred to as "disclosure"). The present application also relates to the scope or equivalent range of the technical idea recited in the spirit or claims. In addition, the configuration of the embodiments (examples) described below is merely an example, and those skilled in the art can make various changes and modifications as long as they are within the scope of the technical idea disclosed in the present specification.

[0069] In addition, in the drawings illustrating the present application, the same symbols are used for elements having the same or similar functions, and the description of the repeated functions and the like will be omitted even if different names are used, as appropriate.

[0070] In the following description of embodiments, the term "magnified virtual image" is used to refer to a virtual image formed in space by an optical assembly using a concave mirror. The term "magnified real image" is used to refer to a real image formed in space by an optical assembly using a lens group or a convex lens. These terms can also be referred to as "magnified image", "virtual image", "real image", etc. In the description of embodiments, the term "magnified virtual image" is used as a representative example of these terms.

[0071] The present disclosure relates to an optimal design method of an optical assembly for displaying an image of a small-sized image light source that generates an image light beam with a narrow divergence angle in the form of a magnified image of a virtual image or a real image, and embodiments of a virtual image optical assembly obtained thereby and an optical system to which the optical assembly is applied. According to the present disclosure, in an optical assembly using a projection lens to obtain a magnified real image and an optical assembly using a concave mirror to obtain a magnified virtual image, optimal design is performed by considering the divergence characteristics of image light emitted from an image source, thereby reducing the large-diameter of the optical assembly, reducing the number of lenses and mirrors, and thus obtaining an optical assembly structure with high cost performance. In particular, since the brightness of the magnified virtual image is equal to the brightness of the light source, the optical assembly has superior light energy conversion efficiency.

[0072] The vehicle information display system of the present invention is summarized as follows, Figure 4A is a top view of an information display device 1000 according to an embodiment of the present invention mounted on a vehicle such as an automobile, a train, an airplane, etc. In front of the driver's seat of an automobile 1010, there is a front windshield glass 6 as a projection member. The inclination angle of this front windshield glass 6 with respect to the vehicle body varies depending on the type of automobile. In addition, the inventors have investigated the radius of curvature thereof in order to realize an optimal virtual image optical assembly. As a result, it has been found that, as shown in Figure 4B , the radius of curvature of the front windshield glass 6 with respect to the horizontal direction of the ground surface of the automobile, i.e., the horizontal radius of curvature Rh, and the radius of curvature with respect to the vertical direction of the ground surface of the automobile, i.e., the vertical radius of curvature Rv, are different from each other, and they generally satisfy the following relationship:

[0073] Rh > Rv

[0074] In addition, it has been found that the difference between these radii of curvature, i.e., the ratio of Rh to Rv, is generally in the range of 1.5 to 2.5 times.

[0075] In the present invention, the reflected display of image information is performed by the front windshield glass observed by the driver in order to observe the outside scenery during driving. The information display device provides a high-brightness virtual image that can be properly displayed by emitting an image light beam with a narrow divergence angle and adjusting the emission direction thereof in accordance with the position of the screen, so that the optical assembly of the head-up display device can effectively capture the incident light beam.

[0076] One embodiment of the head-up display device is an information display device that displays a virtual image on a projection surface. Inside a housing with a partial opening, it comprises an image light generating component that generates the displayed image information and a light source device that provides light to the image light generating component. This light source device has an optical element disposed between the surface light source and the image display device (liquid crystal panel) that converts the light generated by the surface light source into light with a desired divergence angle, and has means for controlling the divergence angle and pointing characteristics.

[0077] The present invention relates to a first information display device for a vehicle information display system. Figure 1 This is a schematic diagram of the peripheral equipment structure of the first type of information display device for a vehicle information display system of the present invention. Here, an example is given of an information display device 100 that projects an image onto the windshield 6 of a car. The head-up display device of the information display device 100 of the first embodiment of the present invention is a device that forms a virtual image V1 on the driver's line of sight (the viewpoint to be described in detail later) 8 in front of the vehicle and displays various information reflected by the projection component (in this embodiment, the inner surface of the windshield 6) in the form of a virtual image VI, also known as a HUD (Head-Up Display). The diagram shows the control device 40 that constitutes the related HUD, which obtains various information such as the road speed limit, the number of lanes, and the planned driving route of the vehicle set in the navigation system 61 corresponding to the current position of the vehicle as foreground information (i.e., the information displayed in front of the car by the virtual image mentioned above).

[0078] Furthermore, the illustrated driver assistance ECU 62 is a control device that controls the drive system and control system based on obstacles detected by the surrounding monitoring device 63 to achieve driver assistance control. Such driver assistance control includes well-known technologies such as cruise control, adaptive cruise control, pre-collision safety systems, and lane keeping assist.

[0079] The surrounding monitoring device 63 shown in the figure is a device for monitoring the situation around the vehicle, such as a camera that detects objects around the vehicle based on images taken of the vehicle's surroundings, or a detection device that detects objects around the vehicle based on the results of transmitting and receiving detection waves.

[0080] The control unit 40 of the aforementioned HUD device acquires foreground information from information obtained from the driver assistance ECU 62 (e.g., distance to the vehicle ahead, orientation of the vehicle ahead, location of obstacles or signs, etc.). Furthermore, the control unit 40 also receives ignition (IG) signals and vehicle status information. This vehicle status information refers to information acquired as vehicle information that does not require high-resolution display, such as fuel remaining and coolant temperature related to internal combustion, including pre-defined abnormal status warnings. It also includes the operation result of the steering indicator, the vehicle's speed, and gear shift position information. The control unit 40 is activated upon receiving the IG signal. This concludes the description of the overall information display device system of this embodiment.

[0081] Furthermore, the projected component can be any component used for projecting information, not just the aforementioned windshield 6, but also other components, such as a combination screen. In other words, as long as the information display device 100 of this embodiment can form a virtual image in front of the vehicle so that the driver can see it in their line of sight 8, it is acceptable.

[0082] In the information display device 100 with the above structure, the image displayed by the image display device 104, which projects image light to display information, forms a virtual image through concave (freeform) mirrors 105 and 106, and the resulting distortion and aberration are corrected by the shape of the two mirrors. The image beam emitted by this information display device 100 is directed to the windshield 6 from the opening (not shown).

[0083] Furthermore, as a second embodiment of the information display device 100, such as Figure 1 As shown, the image displayed by the image display device 103 can be directly reflected into the driver's line of sight. Its structure and function will be explained below. Figure 3 Detailed Description. The image display device 4 has a control device 40 (not shown) for controlling the backlight. Furthermore, in the first embodiment described above, the optical components including the image display device 104 and the backlight 102 are a virtual image optical system, which will also be described below, and includes a concave mirror 1 for reflecting light. On the other hand, the second embodiment directly reflects the high-brightness displayed image of the image display device 4 onto the windshield 6 and towards the driver's line of sight 8.

[0084] In addition, such as Figure 1 As shown, image display devices 103, 104 and Figure 3 The image display device 4 shown can be, for example, a backlit LCD (Liquid Crystal Display), or a self-emissive VFD (Vacuum Fluorescent Display).

[0085] On the other hand, such as Figure 2As shown, the image from the image display device 403 can be reflected as a virtual image by the concave mirror 1a to the driver's viewpoint 8 via the projection component, i.e., the windshield 6 or the combination screen (not shown).

[0086] Here, in order to reduce the distortion of the virtual image, the shape of the concave mirror 1a is as follows: Figure 2 The upper part (the light-reflecting area below the windshield 6, which is relatively close to the driver's viewpoint 8) has a smaller radius of curvature, resulting in a larger magnification. The lower part (the light-reflecting area above the windshield 6, which is relatively close to the driver's viewpoint), on the other hand, has a relatively larger radius of curvature, resulting in a relatively smaller magnification. Furthermore, the image display device 4 is tilted relative to the optical axis of the concave mirror 1a, which can correct for differences in virtual image magnification, thereby reducing distortion and achieving a better correction effect.

[0087] On the one hand, the windshield of a passenger car, such as Figure 4B As shown, the radius of curvature Rv in the vertical direction and the radius of curvature Rh in the horizontal direction of the main body are different, generally Rh > Rv. Therefore, if the windshield 6 is considered as a reflective surface, it is the same as the concave surface of the concave mirror 1. Therefore, in the information display device 100 of this embodiment, the shape of the concave mirror 1 should be adjusted according to the shape of the windshield to correct the virtual image magnification, that is, different average radii of curvature are used in the horizontal and vertical directions to correct the difference in the radius of curvature of the windshield 6 in the vertical and horizontal directions. At this time, the shape of the concave mirror 1 is a spherical or aspherical surface with optical axis symmetry, which is a function of distance from the optical axis r. Since the shape of the horizontal and vertical cross sections at a distance cannot be controlled independently, it is best to use a freeform surface as shown below, with the optical axis plane coordinates (x, y) function of the mirror surface for compensation.

[0088] According to the following implementation methods, for example, Figure 25 As shown, a high-resolution magnified image BB' can be displayed behind the concave mirror. In this case, by reducing the scattering angle of the image light emission to an acute angle and adjusting it to a specific polarization, the concave mirror can effectively reflect only normal reflected light.

[0089] When using a liquid crystal display panel (LCD panel or display panel) as an image display device to obtain image light with specific polarization, a polarization cancellation element can be placed on the observer side of the LCD panel, i.e., the side with the optical components. Through optical transformation, a portion of the image light is converted to polarization in other directions, thus converting it into near-natural light. In this way, even if the observer is wearing polarized sunglasses, they can view a high-quality magnified virtual image.

[0090] Commercially available polarization elimination elements include CosmoShine SRF (manufactured by Toyobo Co., Ltd.) and polarization-removing adhesive (manufactured by Hase Kogyo Co., Ltd.). CosmoShine SRF reduces interface reflection and increases brightness by applying an adhesive to the image display device. Additionally, the polarization-removing adhesive can be applied between the liquid crystal panel image display device and a colorless transparent plate as an adhesive. In this embodiment, as described above, the image display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light with narrow-angle diffusion characteristics and specific polarization. Therefore, efficient light utilization can be achieved, and an optical system realized by a low-power, portable, and small image display device can be obtained, enabling outdoor viewing of magnified virtual images—something unattainable with conventional virtual image technology.

[0091] Furthermore, the energy consumption can be significantly reduced through the light source device and optical components disclosed herein. Combined with a novel small image display device (liquid crystal display panel), a low-power, portable magnified virtual image display system can be provided. According to the technology disclosed herein, an image display device capable of displaying a unidirectional magnified virtual image visible from a specific direction inside a vehicle, for example through the windshield, rearview glass, and side windows, can be provided.

[0092] Next, as an embodiment of the invention disclosed in this application, the function of the optical system for obtaining a magnified virtual image and specific embodiments of the optical system will be described. Figure 26 The basic structure of an optical system for obtaining a magnified virtual image is shown. The object (AA') is placed on one side of the mirror surface at the focal point F of the concave mirror 1'.

[0093] At this time, PB” / AA’=PF / AF=f / (fa), PB”=BB’, therefore, BB′ / AA′=f / (fa) (1)

[0094] Due to the similarity between △PA”F and △BB'F

[0095] BB′ / PA′′=BF / PF=(b+f) / f (2)

[0096] Because PA” = AA’, therefore: BB′ / AA′ = (b+f) / f

[0097] Since the left-hand sides of formulas (1) and (2) are the same, we obtain:

[0098] (f / (fa))=(b+f) / f

[0099] f2 = (b + f)(fa)

[0100] f2 = bf + f2 - ab - af

[0101] 0 = bf - ab - af, we get: bf - af = ab. Dividing both sides of this equation by abf:

[0102] (bf / abf)-(af / abf)=(ab / abf)

[0103] (1 / a)-(1 / b)=(1 / f) (3)

[0104] Formula (3) is derived from the coordinate definition of the optical components:

[0105] (1 / a) + (1 / (-b)) = (1 / f)

[0106] At this point, the magnification m of the virtual image is: m = b / a

[0107] Therefore, by reducing the distance b (object-point distance) from the object to the concave mirror and increasing the distance from the concave mirror to the virtual image, i.e., the image distance, a high-magnification virtual image can be obtained.

[0108] In the optical system using the aforementioned virtual image optical components, the focal length f must be shortened to reduce the distance from the object point AA' to the concave mirror 1. However, to shorten the focal length, the refractive index of the concave mirror must be increased, which, through conventional optical design methods, would lead to an increase in aberrations in the magnified virtual image, resulting in a blurred magnified virtual image.

[0109] The following figures illustrate a novel design method for a small, high-brightness, and high-resolution virtual image magnification optical assembly. Figure 22 , Figure 23A and Figure 23B These are explanatory diagrams used to illustrate the scattering characteristics of image light emitted from the center of the display screen of an image display device. These diagrams are used to illustrate the scattering characteristics when the liquid crystal panel 104 is used as a display element in an image display device. Figure 23A The image shows an oblique view with the light-emitting surface of the LCD panel 11 facing upwards. For ease of explanation later, the long direction of the image is defined as the X-axis, the short direction as the Y-axis, and the direction perpendicular to the XY plane is defined as the Z-axis. When explaining the scattering angle of the image light, the Z-axis will be used as the axis for displaying relative brightness.

[0110] Figure 27AThis illustrates the basic design environment used in optical system design. The LCD panel is defined as the object plane, and the line segment connecting the center of the screen and the center of the entrance pupil of the optical components is defined as the Z-axis. The LCD panel is positioned on a plane perpendicular to the Z-axis (XY plane). In optical system design, for example, a ray is emitted from the object point Pa at the center of the screen towards the current coordinates of the entrance pupil (which is a virtual plane), relative to the pupil height (-1.0 to +1.0 on the Y-axis, -1.0 to +1.0 on the X-axis). The displacement of the principal ray from its endpoint on the image plane towards the center of the object point and the entrance pupil (relative pupil height (0.0, 0.0)) on the XY plane is defined as the aberration. The optical system is designed to make this aberration zero.

[0111] Traditional optical component design parameters include the configuration and shape of the optical elements between the liquid crystal panel (as the object point) and the magnified virtual image (as the image plane), and the refractive index. In virtual image optical components using concave mirrors, the position and shape of the concave mirrors are the main design parameters. Furthermore, because the diameter of the human eye's pupil varies depending on the amount of incident light entering the retina (the pupil diameter can vary between 4mm and 8mm depending on the amount of incident light entering the retina), unwanted light can be blocked. Image light exceeding the distance from the image plane to the viewer and the angle covered by the pupil diameter cannot reach the retina. Therefore, when designing this optical component, the role of the human eye's retina as a light-blocking material must be fully considered.

[0112] In this invention, a liquid crystal panel is used as the image display device, and the diffusion characteristics of the light source device are made to have a narrow angle. The diffusion of image light is adjusted by the shape and surface roughness of the reflective light guide of the light source, which are used as new optical component design parameters. In the embodiments of the invention described below, the horizontal (longitudinal) diffusion characteristics of the screen are designed to be ±9 degrees at 50% relative brightness and ±16 degrees at 0% relative brightness; the vertical (width) diffusion characteristics of the screen are designed to be ±7.5 degrees at 50% relative brightness and ±13 degrees at 0% relative brightness. The optical component that emits the image beam from the object point Pa at the center of the screen is as follows: Figure 24A As shown, the coordinates corresponding to the relative pupil height and the resulting aberrations are as follows: Figure 24B As shown, the aberration region of the image beam generated by the image light source of the present invention is range B, which is closer to the principal ray than the range A corresponding to the divergence angle of the beam required to obtain the same brightness in conventional designs. Therefore, the amount of aberration itself is greatly reduced.

[0113] In addition, such as Figure 27B As shown in (2), regarding the image beam emitted from the object point Pb around the screen, and Figure 27B(2) The aberrations in the meridian section direction shown are the same as those in the spherical segment section direction shown in the figure. The aberration region of the image beam generated by the image light source of the present invention, which has a narrow divergence angle diffusion characteristic, is in the B range. Therefore, compared with the A range corresponding to the beam divergence angle required to obtain the same brightness in the conventional design, it is closer to the principal ray, so the aberration amount itself is greatly reduced.

[0114] In traditional optical systems, if aberration correction capabilities are insufficient, good focusing performance can be achieved by optimizing the diameter of the lens barrel used to fix the lens elements in the optical components, determining the effective diameter of the lens by configuring the lens group, adjusting the width of the imaging beam at the center of the image to determine the brightness (F-number), and blocking the parts with larger aberrations. Furthermore, for beams imaging around the perimeter of the image, the effective diameter of the lens is determined by configuring the lens group, and focusing performance that is not problematic in practical use is achieved by blocking the light with larger aberrations. On the other hand, to ensure sufficient brightness both in the center and around the screen, the number of transmitted beams must be increased as much as possible.

[0115] This is because the cosθ between the object plane and the magnified projected image plane... 4 As a rule, the relative brightness of the surrounding image surfaces will further decrease, making it more difficult to make them equal to the brightness of the center of the screen.

[0116] In contrast, the optical system of the present invention, as described above, is equipped with a light source device that can control the image beam emitted by the image display device having narrow-angle scattering characteristics, causing it to be emitted in the direction required by the optical components. The light source device having narrow-angle scattering characteristics and controllable light emission direction, and its surface light source LED (Light Emitting Diode), will be described in detail below.

[0117] The present invention describes a surface-emitting LED and its light diffusion characteristics. A typical surface-emitting white LED involves coating a yellow phosphor (containing both green and red light) onto the surface of a blue LED. Yellow light is emitted by exciting the yellow phosphor, thus mixing to produce white light. The light diffusion characteristics of a typical surface-emitting white LED are such that, when the emitting surface of the LED light source faces upwards, the relative brightness corresponding to the divergence angle of the light emitted from its emitting point is as follows: Figure 5 The complete diffusion distribution shown is typically achieved through the following structure of a light source device: To capture light with a large divergence angle, optical components are usually positioned close to the surface light source LED. To more easily control the diffusion characteristics and directionality of the LED's emitted beam, the emitted beam is first converted into a parallel beam by optical components (optical elements). Then, optical elements installed between the liquid crystal panel and the optical components control the diffusion and directionality.

[0118] The optical components used in traditional light source devices, such asFigure 20 and Figure 21 As shown, multiple LEDs are positioned close to their corresponding plano-convex lenses LA to convert the diverging beams emitted by the LEDs into approximately parallel light. The directional characteristics of the beams are controlled by optical elements LB and FL located between the LCD panel and the LEDs, and the diffusion angle of the beams is controlled by diffuser plates DF1 and DF2. In traditional optical systems, the incident beam angle of each optical element is relatively large, resulting in increased reflection loss.

[0119] also, Figure 20 and Figure 21 The conventional light source device shown uses optical components composed of multiple optical parts (elements) arranged together. Figure 20 In the first conventional example shown, there are 5 reflective surfaces. Figure 21 In the second conventional example shown, there are seven reflecting surfaces. When light is incident perpendicularly on an optical element with a refractive index of 1.5, the reflectivity is 5% per surface. As mentioned earlier, due to the larger incident angle of the conventional light source device, the reflectivity is further increased, with an average reflectivity exceeding 8%. In the first conventional example, there are five reflecting surfaces, and the reflection loss of the entire optical assembly is over 40%. On the other hand, in... Figure 21 In the second example shown, there are 7 reflective surfaces, so the reflection loss of the entire optical system is more than 56%, which greatly reduces the light utilization efficiency of the light source device.

[0120] A first embodiment of the optical components used in the light source device of the present invention:

[0121] The following examples are used to illustrate this. Figure 6 and Figure 7 Based on the white LED shown, an image display device is described. Figure 6 The first white LED shown and Figure 7 The difference between the second white LED shown is that, in the first embodiment, the peak wavelength of the emitted light from the blue LED, which excites yellow phosphors containing green and red, is on the shorter wavelength side, thus obtaining white light with a high color temperature. The light source device of this image display apparatus has an optical assembly with optical elements that can control the divergence angle and direction of the divergent light emitted by this white LED. The intensity of the obtained light source can be modulated according to an image signal, and an image can be displayed on a color-filtered LCD, which serves as the image display element.

[0122] In the following embodiments, a light source device using a color-filtered LCD screen as an image display element and a light source optical assembly equipped with this light source device will be described. As the light source optical assembly of the embodiments of the present invention, the LCD screen light source can also serve as a highly efficient light source, and therefore can be used in projection-type image display devices and other HUD image display devices.

[0123] The following describes the characteristics of the light source device, optical components, and their respective optical parts in the image display apparatus that implements the embodiments of the present invention.

[0124] The light source in the optical component of this invention is a surface-emitting solid-state light source, using a blue LED, which is mixed with yellow light generated by exciting a yellow phosphor containing green and red light to obtain a white LED that emits white light. Its diffusion characteristics are as follows... Figure 1 The diagram shows a completely diffused distribution. To capture and efficiently utilize light from a source with a large divergence angle, the lighting optics require a plano-convex lens with a large-aperture receiving surface near the LED emitting surface. In the design of the lighting components, the area and divergence angle of the emitting surface must satisfy the same luminance invariant characteristic as the area and focusing angle of the receiving surface (e.g., ...). Figure 26 As shown, traditional light source optical components suffer from the problem of inefficiently utilizing the divergent beam of an LED. This invention solves these problems through the following technical means.

[0125] In an embodiment of the present invention, the divergence angle of the light source is shown in Figure 23, exhibiting a narrow-angle divergence characteristic. Compared to the complete diffusion characteristic of a typical surface-emitting LED shown in the figure, the divergence angle of the emitted light beam is narrow, thereby increasing the light energy density and improving the brightness of the image displayed on the subsequent LCD. Figure 14 and Figure 15 As shown, the narrowing of the diverging beam and the control of its directivity are achieved through the function of a single light source module containing a reflective optical element 11. The narrowing of the diverging beam is controlled by the shape of the reflective surface of the reflective optical element 11, while the directivity can be easily adjusted by optimizing the relationship between the focal position of the reflective surface and the luminous center position of the surface-emitting white LED in the XY plane.

[0126] As described above, in embodiments of the present invention, by arranging a diverging beam with a narrow divergence angle and a single light source module with controllable directivity in the surface direction, the diverging beam of the surface-emitting LED can be precisely controlled like a laser (LASER, Light Amplification by Stimulated Emission of Radiation).

[0127] In an embodiment of the present invention, the surface-emitting LED is placed Figure 10 At the focal point of the reflective surface shown, the divergent light from the surface light source is converted into a beam approximately parallel to the optical axis (Z-axis) of the reflective surface. In this case, since the reflective surface primarily controls the diffusion characteristics of the diffused light, even a white light source will not produce chromatic aberration. The surface light source 1 cannot be spatially arranged and cannot capture the light in region a; therefore, it is necessary to cut off the corresponding reflective surface, such as... Figure 12 and Figure 13As shown, the end face is designed to be approximately flat so that the LED driver substrates can be arranged close together.

[0128] The composite focusing of reflective optical elements, and the shape of surface-emitting LED elements as shown in... Figure 8 As shown, it is encased inside a shell containing a blue LED, and the phosphor is encapsulated around it with inorganic encapsulation material. Figure 9 This is a cross-sectional schematic diagram of a standard surface-emitting white LED. The blue LED chip (component) 5 is mounted on the substrate 6. The blue light emitted from it is used as excitation light by the surrounding encapsulated green and red light-emitting yellow phosphors to achieve [the desired effect]. Figure 6 and Figure 7 The image shows white light containing the three primary colors of blue, green, and red. In a typical surface-emitting white LED, due to the surrounding area of ​​the blue LED element (…),… Figure 9 Region 2) has the strongest light intensity, therefore it generates the highest proportion of white light in the encapsulated phosphor.

[0129] In an embodiment of the present invention, by Figure 16 and Figure 17 The reflective polarizer 19a is equipped in the optical assembly of the light source shown. Figure 17 (A)) can reflect P-polarized light. The blue component of the P-polarized light returned by the surface-emitting white LED serves again as the excitation light for the phosphor, thus causing it to emit light on the phosphor surface. Figure 9 Region 3). Therefore, the surface-emitting white LED used in this embodiment not only has a high luminous intensity in region 2, but also has a high luminous intensity in the region near the phosphor coating surface (region 3 in the figure).

[0130] As a result, multiple high-intensity light-emitting points are formed along the Z-axis in the embodiment, thereby increasing the degree of freedom in controlling the topological properties of the reflective optical element. This is the first unique advantage of this invention.

[0131] In embodiments of the present invention, multiple focal points can be achieved along the aforementioned Z-axis direction. Specifically, when optimizing the focal point position of the reflective optical element 11, a surface-emitting white LED is configured in... Figure 10 The parabolic focal point is shown. This results in multiple luminous points along the Z-axis, necessitating a new design concept for the composite focal reflector.

[0132] Furthermore, a common method to improve the light utilization efficiency of surface-emitting white LEDs is to reduce the emitting area. Therefore, the emitting area of ​​surface-emitting white LEDs with high light output has decreased rapidly in recent years. In embodiments of the present invention, it is necessary not only to optimize the optimal shape of the multiple emitting points formed by the reflective optical element 11 along the Z-axis, but also to consider the assembly precision of the miniaturized surface-emitting LED. Figure 8 As shown, even if the light-emitting point moves along the XY direction within the light-emitting surface, the light receiving efficiency will not decrease significantly as long as there is a light-emitting point within a specific range. That is, in order to reduce assembly precision, it is necessary to design a composite focal reflection optical element 11 with multiple focal surfaces in the XY plane.

[0133] The following is a design description of the reflective surface of a reflective optical element 11 with multiple focal points in the horizontal and vertical directions. Figure 10 This is a schematic diagram of the vertical cross-section of the reflective optical element 11, showing the vertical cross-section of the element along the Z-axis. In region a along the Z-axis, since the divergent light from the surface-emitting white LED located at the focal point cannot be captured, therefore... Figure 12 On the cross-section of the optical element 11 shown, a hole is provided in a portion of its end face (e.g. Figure 13 (As shown), the refraction effect created by the shape of this aperture allows the surface-emitting white LED to be positioned optimally along the Z-axis of the reflective optical element. At this point, as... Figure 13 As shown, a nearly cylindrical aperture is provided on the end face of the reflective optical element 11 (also known as a single light source module) at the portion aligned with the optical axis, and a surface light source white LED is arranged within this space. Since the reflective optical element and the light-emitting LED are arranged close together in the nearly cylindrical aperture, it is recommended to select a high-temperature resistant plastic material (heat distortion temperature above 120 degrees Celsius). Furthermore, when manufacturing the aperture, a draft angle of at least 2 degrees should be provided between the end and the tip of the mold to facilitate easy removal from the mold during molding, thereby significantly improving the demolding performance of the molded part.

[0134] Figure 13 The diverging light emitted by the surface-emitting white LED, after being refracted by the wall of an approximately cylindrical aperture, originally diverged in the direction shown by the dashed line (incident angle θ5 relative to the wall). However, due to refraction at the wall, the divergence direction changed to the direction shown by the solid line (incident angle θ4 relative to the wall). Therefore, relative to... Figure 13The first focal point of the single light source module at the intersection of the dashed lines (i.e., the LED light source placement position) generates a second focal point (distance L1) slightly further away in space. The position of this second focal point can be arbitrarily designed based on the inner diameter of the approximately cylindrical shape, the inclination angle of the wall surface, and the refractive index of the material; these parameters are all valid design parameters in the shape design of a single optical module. The light beams refracted by the aforementioned cylindrical side surface and reflected by the reflecting surface of the single optical module (region b in the figure) are converted into approximately parallel beams and emitted towards the LED because their respective focal points are parabolic. The region c, farthest from the LED light source, is designed to cause the light to diverge on the parabolic surface.

[0135] The cylindrical vertex facet has a lens shape, and the divergence angle of the surface-emitting white LED is controlled by refraction over a small range of divergence angles. This shape design, as illustrated, allows for more precise control of the light distribution due to the different refractive forces in regions a and b around the optical axis. The divergence angle of the beam incident on these regions is approximately ±15 degrees, and according to Snell's law, the refracted light can be effectively controlled. As described above, the diverging light from the surface-emitting white LED positioned at the first focal point, after passing through the reflective surface shape of the single optical module in this embodiment of the invention, is as follows... Figure 8 The dashed lines shown form almost parallel beams of light that then shine down onto the color filter LEDs in the lower section.

[0136] On the other hand, the lens effect of the cylindrical sidewalls generates divergent light at the second focal point, as shown by the solid lines in the figure, with several divergent beams emanating from a single optical module. This result allows for... Figure 15 The arrangement of individual light source modules shown can reduce the change in light intensity at the boundary between adjacent optical units, thereby improving the technological potential.

[0137] Next, as Figure 11 As shown in this embodiment of the invention, the refractive power variation of the reflective optical element 11 (single light source module) along the optical axis in different regions is illustrated. During design, compared to region b, the refractive power in region c gradually decreases, while the divergence effect increases. This can mitigate... Figure 15 The brightness of the connecting portion between adjacent individual light source modules in the final configuration shown. During the design process, a uniform light source is observed when the brightness ratio of the image light emitted by the LCD panel with the color filter at the connecting portion of the individual light source modules is less than 3%. In this case, in addition to the shape of the individual light source modules, the influence of design parameters can be mitigated by the action of the optical thin film controlling the diffusion angle, as described later.

[0138] Regarding the description of the versatility of the single light source module of the present invention, the final light source unit 12 is as follows: Figure 15As shown, it is composed of multiple individual light source modules 13 arranged together. Table 1 shows a representative example of a commercially available automotive LCD with a color filter. To ensure component compatibility, individual light source modules of the same shape (hexagonal circumcircle diameter of 16mm) were arranged together. The results show that individual light source modules can use inserts of the same shape in the mold used for molding the light source unit, thereby improving development efficiency.

[0139]

[0140] Table 1

[0141] When viewed from the opening, a single light source module 13, having a parabolic surface symmetrical with respect to the optical axis, appears as follows: Figure 14 As shown in the plan view on the right, it is circular. The light source unit, composed of multiple such units, is arranged to minimize space loss, as... Figure 15 As shown, the elliptical shapes containing the reflective region c should be arranged into a hexahedron that appears circular when viewed from above.

[0142] In addition, such as Figure 14 As shown in the plan view on the right, the maximum diameter of the reflecting surface b is aligned with the inscribed circle of the aforementioned hexahedron, and the diffusion characteristics of the regions corresponding to the six vertices of the hexahedron are controlled by the shape of region c. In this way, by arranging individual optical units to form the light source unit 12, good brightness uniformity can be achieved, thereby granting new design freedom.

[0143] Meanwhile, if inexpensive surface-emitting white LEDs can be obtained, and the outer diameter of a single light source module can be reduced while increasing the number of individual light source modules arranged, it will be easier to improve the brightness uniformity of the light source unit.

[0144] In embodiments of the present invention, Figure 16 The diagram shows the cross-sectional structure of the image display device. Below the light source unit 12, which consists of multiple individual light source modules 13, surface-emitting white LEDs corresponding to each individual light source module 13 are arranged, and an LED driver substrate 16 connected in series is configured. This substrate is made of metal to address heat dissipation issues. To reduce differences in luminous intensity, a series connection is preferable for driving the LEDs. However, if the number of connected LEDs is too large, the total voltage will increase, leading to problems in circuit insulation design, etc. Therefore, it is best to limit the number to a maximum of about 10, using a combination of series and parallel connections. When using a combination of inline and parallel connections, the challenge is the difference in driving current between parallel circuits, which can be solved by setting matching impedance circuits on each branch circuit. In this way, the difference in luminous intensity of the surface-emitting white LEDs can be reduced, thereby achieving a high-brightness and uniformly bright image display device.

[0145] Regarding the description of the optical thin film for controlling diffusion characteristics of the present invention, the following section introduces the structure and function of the optical thin film 19 (hereinafter referred to as the light diffusion control film) disposed between the light source unit 12 and the LCD panel 20 with a color filter. Figure 17 The cross-sectional shape of the optical thin film controlling the light diffusion angle is shown. A reflective polarizing plate 19a is provided on the surface in contact with the light source unit 12 to reflect specific polarized light. As mentioned above, the specific polarized light emitted by the light source unit 12 is reflected back to the phosphor of the LED light source 1 in the single light source module 12 and used as excitation light again, thereby increasing the amount of light emitted and improving the luminous efficiency of the input power.

[0146] like Figure 16 As shown, the composite surface of the LCD panel 20 with the light diffusion control film 19 forms a shape like... Figure 17 (A) shows the fine pattern 19b used to control light diffusion. In this embodiment, in order to control the diffusion angle in the horizontal direction of the screen, a structure (H-type cylindrical lens) is provided in which cylindrical lenses are arranged in the horizontal direction of the LCD display screen, thereby controlling the diffusion characteristics in the horizontal direction of the screen (i.e., the left-right direction in the figure) and improving the brightness uniformity of the image displayed on the LCD panel.

[0147] As shown in the enlarged view in section A, the cylindrical lens structure has a convex surface in the light emission direction. By reducing the shape change of the connecting portion between adjacent convex surfaces, a gentle concave surface or a flat concave surface is formed, with no abrupt change in lensing effect between it and the plane. Furthermore, the light diffusion film 19 is arranged relative to the shape of the LCD panel 20 at an angle θ as shown in view B, using cylindrical lenses. This not only avoids moiré patterns caused by pixel interference but also controls light diffusion in the vertical direction, greatly improving the brightness uniformity of the image light emitted from the LCD panel 20.

[0148] The second technique mentioned above to avoid moiré patterns caused by interference with the LCD panel is to choose a lenticular lens spacing that is not an integer multiple of 80μm if the pixel pitch is 80μm. Smaller pitch results in higher screen brightness uniformity. However, due to manufacturing limitations, there are limits to this refinement; choosing a pitch between 100μm and 200μm can achieve good diffusion characteristics without producing moiré patterns.

[0149] The first method to reduce moiré patterns is to tilt the cylindrical lens, with an angle θ between 5 and 15 degrees. According to experimental results, the effect is best within the range of 10 degrees ± 3 degrees.

[0150] The description of the reflective polarizing film reflecting specifically polarized light in this invention involves studying the angular dependence of the transmittance of the reflective polarizing film reflecting specifically polarized light on the transmittance of an optical film controlling the light diffusion angle attached to the side of an LCD. The actual product studied is 3M. TM DBEF-QV2, in addition to studying the wavelength characteristics of the incident light, also investigated the effect of the incident angle on the characteristics. First Figure 18 The characteristics of reflective polarizing films under perpendicular and near-angle incidence are summarized.

[0151] Compared to the transmittance of a specific polarized light (S-polarized light), the transmittance of another polarized light (P-polarized light) varies considerably, but the absolute value of the change is small when the amount of change is less than 5%, making the reflection of P-polarized light feasible. Furthermore, at incident angles of 10 degrees and 20 degrees, there is no significant difference in characteristics; some light from the light source unit 12 with a diffusion angle will also be reflected without angle dependence. For characteristics close to an incident angle of 45 degrees, such as... Figure 19 As shown, it also has good properties.

[0152] In an embodiment of the present invention, a reflective polarizing film is attached to the light source side of the light-diffusing film for testing, similar to the reflection of S-polarized light. The result is that the S-polarized light is reflected back to the light source side, while the P-polarized light enters the cylindrical lens of the light-diffusing film. Because the P-polarized beam has a Brewster angle (0% reflectivity) at approximately 33 degrees of incident angle compared to the S-polarized beam, its refractive index is lower before and after this angle (±15 degrees). Therefore, even without an anti-reflective coating on the cylindrical lens surface, a beam with the desired diffusion angle can be obtained without angle dependence.

[0153] Image light diffusion characteristics of the image display device of the present invention: In order to realize a small and high-brightness image display device, it is necessary to control the directionality of light and obtain image output light with a narrow divergence angle. Figure 23A This is an explanatory diagram illustrating the diffusion characteristics of image light emitted from the center of the display screen of an image display device. It is also an explanatory diagram illustrating the diffusion characteristics of the display element of the image display device using the liquid crystal panel 20.

[0154] In Figure 23, the liquid crystal panel 20 is shown in an oblique view with the light-emitting surface facing upwards. For ease of subsequent explanation, Figure 23A The coordinate axes will be defined with the long side of the screen as the Y-axis, the short side as the X-axis, and the direction perpendicular to the plane formed by the X and Y axes as the Z-axis. In the description of the image light divergence angle in 23B, the Z-axis is described as an axis representing relative brightness.

[0155] In this invention, as an image display device, while using a liquid crystal display panel, the image light is controlled over a wide range by narrowing the angle of the light source device through its diffusion characteristics. To this end, design parameters for a new optical component constituting the light source unit 12 were determined, adjusted by the shape of the reflective optical element and the surface shape of the light diffuser sheet, which is set as needed.

[0156] In the implementation of this invention, the characteristic design values ​​are as follows: the horizontal (long side direction) diffusion characteristics of the screen are ±9 degrees at a relative brightness of 50% and ±16 degrees at a relative brightness of 0%. The vertical (short side direction) diffusion characteristics of the screen are ±7.5 degrees at a relative brightness of 50% and ±13 degrees at a relative brightness of 0%.

[0157] At this point, the brightness of the image displayed on the image display device is approximately 10 times that of a standard image with near-perfect diffusion characteristics, achieved by characteristic C of the present invention. Furthermore, characteristic A, with its narrow-angle diffusion characteristic, further enhances the brightness. However, it should be noted that the pointing characteristics of the light source device need to be adjusted according to the observer's viewing angle, which presents new challenges for the light source device.

[0158] The eccentricity invariant is specified for the brightness of optical components.

[0159] Finally, a description of the light diffusion for rotationally symmetric planar apertures applicable to lighting systems is provided, as follows: Figure 26 As shown. When the refractive index is equal:

[0160] D in SIN in =D out SIN out ,

[0161] This indicates that there is a trade-off between angle and area.

[0162] In other words, reducing the angular distribution to form a collimated beam expands the space, while concentrating the light increases the angular distribution but shrinks the space, which remains constant. Therefore, once the image display area S1 of the LCOS panel, which serves as the light-receiving surface, is determined, the emission angle that can be captured is also determined.

[0163] Therefore, this invention realizes an optical component based on a new design concept, namely, by superimposing the focal position of the reflective optical element 11 on the optical axis to realize a single light source unit, the optical component of which is not governed by the invariant of equidistant luminance.

[0164] Various embodiments have been described in detail above, but the present invention is not limited to the embodiments described above, and includes a wide variety of different variations. For example, the above embodiments have provided a detailed description and explanation of the entire system for easier understanding, but are not limited to products that must have all of the aforementioned components.

[0165] Furthermore, some components of certain embodiments can be replaced with components of other embodiments, or the components of one embodiment can be combined with the components of other embodiments. In other words, for a part of the components of each embodiment, other components can be added, deleted, or replaced.

[0166] Control of the diffusion and pointing characteristics of light emitted from a liquid crystal panel: In typical television applications, the light emitted from a liquid crystal display panel, for example... Figure 24A "Traditional characteristics (X direction)" and Figure 24B As shown by the curve of "Traditional Characteristics (Y Direction)" in the image, in the horizontal direction ( Figure 24A The display direction corresponding to the X-axis of the curve and the vertical direction of the screen ( Figure 24B The curves exhibit similar diffusion characteristics in the direction corresponding to the Y-axis of the curve.

[0167] In comparison, the diffusion characteristics of the emitted light beam of the liquid crystal display panel in this embodiment are as follows: Figure 24A "Example 1 (X direction)" and Figure 24B The diffusion characteristics are shown by the curve in "Example 1 (Y direction)".

[0168] In a specific example, when the brightness is set to 50% of that at a relative frontal viewing angle (0 degrees) (brightness reduced by about half), the field of view is set to 13 degrees. Compared to the scattering characteristics of a typical home television device (62 degrees), this field of view is about 1 / 5. Similarly, in examples where the vertical field of view is not uniformly set, by optimizing the reflection angle and reflective area of ​​the reflective light guide, the upper field of view can be suppressed to about 1 / 3 of the lower field of view (reduced).

[0169] By adjusting the field of view as described above, the amount of image light in the direction of the user's viewing (the direction of the user's line of sight) is greatly increased compared to traditional LCD TVs (significantly improving image brightness), with the image brightness reaching more than 50 times.

[0170] Furthermore, in the case of the field of view characteristics shown in "Example 2" of Figure 24, when the field of view is set to 5 degrees, which is 50% of the brightness when viewed from the front (angle 0 degrees) (the brightness is reduced by about half), the field of view is about 1 / 12 of the diffusion characteristics (angle 62 degrees) of a typical home television device (narrow field of view). Similarly, in the example where the upper and lower field of view are set equally in the vertical direction, by optimizing the reflection angle and reflection area of ​​the reflective light guide, the relevant vertical field of view can be controlled (narrowed) to about 1 / 12 of that in the conventional method.

[0171] By making such settings, the image brightness (light intensity) in the viewing direction (the user's line of sight) is significantly improved compared to traditional LCD TVs, with the brightness of the relevant image reaching more than 100 times.

[0172] Optical component design suitable for image light with narrow divergence angles: As mentioned above, by making the field of view narrow, the light beam can be concentrated on the optical component. Therefore, using the aforementioned optical components for image sources not only significantly improves the utilization efficiency of image light but also gives the image beams emanating from each image source a narrow divergence angle and high-density light energy. Thus, even small-aperture optical components can obtain real or virtual images with sufficient brightness. The aberrations produced by small-aperture optical components are reduced, simplifying correction and enabling bright and high-resolution magnified images. Consequently, an image display device with low power consumption, high precision, and high brightness magnified images can be achieved using a few lenses and concave mirrors.

[0173] When using a large-size LCD panel as an image source, it is advisable to direct the light around the screen towards the optical components when the center of the image is directly facing the viewer to improve the overall brightness of the screen. On the other hand, when the panel size (16:10 aspect ratio) of the image display device is 3 inches or less, the image of the LCD panel described in this embodiment can be used vertically (hereinafter also referred to as "vertical use"), which can significantly narrow the horizontal pointing characteristic angle, thereby realizing a high-brightness or low-power image display device.

[0174] Furthermore, through the aforementioned light source device, and... Figure 24A and 24B Compared to the light diffusion characteristics (referred to as "conventional characteristics" in the figure) of a conventional liquid crystal display panel, the pointing characteristics in the X and Y directions can be significantly narrowed. In this embodiment, by having such narrow-angle pointing characteristics, an image display device can be realized that emits approximately parallel image beams in a specific direction, thus emitting light with a specific polarization and a narrow divergence angle.

[0175] The second type of information display device for vehicle information display systems: as described above, Figure 3(This is an embodiment of a second vehicle information display system with a narrow divergence angle high-efficiency light source device). A specific polarized image beam obtained by a compact and lightweight narrow divergence angle high-brightness image display device 4 is reflected through the windshield 6, allowing the driver to see a virtual image. Because the information display device of the second embodiment has the aforementioned light source device, it has high light conversion efficiency and low power consumption. It can be powered by a portable battery, is portable, and can be placed on the dashboard 42 when needed. By adjusting its orientation and height relative to the windshield 6, it can be positioned in the optimal viewing position for the driver.

[0176] Sunlight entering the car is reflected after passing through the windshield (6), with S-polarized light being almost entirely P-polarized light. The polarizer on the incident surface of the LCD panel is typically an absorptive polarizer that absorbs P-polarized light. Therefore, placing an optical film or glass capable of reflecting P-polarized light on the windshield side of the absorptive polarizer can significantly improve the reliability of components including the LCD panel.

[0177] When using the liquid crystal panel described in this embodiment as a specific polarization image light emitting device, the brightness is significantly reduced when polarized sunglasses are used due to the high surface reflection of the sunglasses. To solve this problem, by attaching a polarization cancellation element to the emitting surface of the liquid crystal panel, the image light can be converted into a mixture of P-polarized and S-polarized light. In this way, even if the driver wears polarized sunglasses, a virtual image with sufficient brightness can still be obtained.

[0178] The various embodiments or examples (i.e., specific examples) of applying the present invention have been described in detail above. On the one hand, the present invention is not limited to the embodiments (specific examples) described above, but also includes various modifications. For example, the above embodiments have described the entire system in detail for the purpose of more clearly illustrating the present invention, and are not limited to having all the structures described. Furthermore, a part of the structure of one embodiment can be replaced with the structure of another embodiment, and the structure of one embodiment can be added, deleted, or replaced in the structure of another embodiment. The above-described light source device is not limited to optical systems with image sources having narrow divergence angle characteristics and virtual image display devices having the above-described optical systems, but is also applicable to display devices such as HUDs, tablet computers, and digital signage.

Claims

1. A vehicle-mounted information display device and system with a solid-state light source, characterized in that: A virtual image display device is provided, wherein the virtual image display device includes an optical system, the optical system including an image display device for displaying an image, a light source device having a surface-emitting solid-state light source for providing light to the image display device, and an optical component for receiving image light from the image display device. The aforementioned light source device comprises a light source unit consisting of multiple individual light source modules arranged in a two-dimensional arrangement, an optical film, and an image display device. Its individual light source module consists of a blue solid-state light source that excites a yellow phosphor containing green and red light to produce a white surface-emitting solid-state light source that emits white light by mixing with the blue light, and an optical element that can reduce the divergence angle of the beam emitted by the white surface-emitting solid-state light source. The aforementioned image display device directs a white light beam emitted by the aforementioned light source unit onto the image display device and adjusts the intensity of the light according to the image signal to display an image on the screen; The aforementioned light source module has a cylindrical hole near the focal point of the reflective optical element end face to reflect the beam of light emitted by the white surface-emitting solid light source into almost parallel light through the reflective surface; the white surface-emitting solid light source is installed in the aforementioned hole, and the optical film is placed between the light source unit and the aforementioned image display device; A cylindrical lens is designed on one side of the image display device of the aforementioned optical film, and a reflective polarizer is attached to the other side.

2. The vehicle information display device and system with a solid-state light source according to claim 1, characterized in that: Light is provided to the aforementioned image display device by the aforementioned light source device. The light source device has an optical unit composed of multiple individual light source modules arranged in two dimensions. Each individual light source module has a hole on its end face and presents an approximately cylindrical shape along the optical axis direction containing the focal point of the reflective optical element. Part of the divergent light emitted by the surface-emitting solid light source is refracted by the cylindrical side surface. The aforementioned reflective optical element of the aforementioned single light source module can reflect light at different positions of the reflective surface and convert the diverging beam of the aforementioned surface-emitting solid light source into a narrow diverging angle beam.

3. The vehicle information display device and system with a solid-state light source according to claim 2, characterized in that: The light source device has a light source unit composed of multiple individual light source modules arranged in two dimensions. The end face of each individual light source module is provided with a hole and is approximately cylindrical in shape along the direction of the focal point and optical axis of the reflective optical element. Part of the divergent light emitted by the surface-emitting solid light source is refracted by the cylindrical side surface. The hole designed on the end face of a single light source module is approximately cylindrical in shape along the optical axis containing the focal point of the reflective optical element. A portion of the diffused light from the surface-emitting solid-state light source is refracted through the side of this cylindrical shape. By reflecting the light at different positions on the reflective surface of the aforementioned reflective optical element, the divergent beam emitted from the surface-emitting solid-state light source diverges along the optical axis of the reflective optical element through multiple focal points and is converted into a divergent beam with a narrow divergence angle.

4. The vehicle information display device and system with a solid-state light source according to claim 3, characterized in that: The aforementioned single light source module is equipped with a reflective optical element that does not have a shape for generating diffused light. Instead, it emits a beam of light in an approximately parallel light form through the reflective optical element. The S-polarized beam in the incident light source light is reflected by the reflective polarizer. The light is reflected again by the reflective surface of the reflective optical element and returns to the phosphor of the white solid light source element, thus exciting the phosphor.

5. A vehicle information display device and system with a solid-state light source according to claim 4, characterized in that: The aforementioned light source device includes a light source unit composed of multiple individual light source modules arranged in a two-dimensional manner, an optical film, and an image display device; Its individual light source module consists of a blue solid-state light source that excites a yellow phosphor containing green and red light to produce a white surface-emitting solid-state light source that emits white light by mixing with the blue light, and an optical element that can reduce the divergence angle of the beam emitted by the white surface-emitting solid-state light source. The aforementioned image display device directs a white light beam emitted by the aforementioned light source unit onto the image display device and adjusts the intensity of the light according to the image signal to display an image on the screen; The aforementioned light source module has a cylindrical hole near the focal point of the reflective optical element end face to reflect the beam of light emitted by the white surface-emitting solid light source into almost parallel light through the reflective surface. The white surface-emitting solid light source is installed in the aforementioned hole. The aforementioned optical film is installed between the aforementioned light source unit and the aforementioned image display device. The spacing of the cylindrical lenses designed on the side of the aforementioned optical film on the image display device side should be selected as a value other than an integer multiple of the pixel spacing of the image display device. A reflective polarizer is attached to the side of the light source unit.

6. A vehicle information display device and system with a solid-state light source according to claim 5, characterized in that: The spacing of the cylindrical lenses designed on one side of the aforementioned optical film image display device is selected as a value other than an integer multiple of the pixel spacing of the image display device, and is in the range of 100 micrometers to 200 micrometers.

7. A vehicle-mounted information display device and system with a solid-state light source, characterized in that: A virtual image display device is provided, wherein the aforementioned virtual image display device includes an optical system. The aforementioned optical system includes an image display device for displaying images, a light source device having a surface-emitting solid-state light source for providing light to the aforementioned image display device, and an optical component for receiving image light from the aforementioned image display device; The aforementioned light source device comprises a light source unit consisting of multiple individual light source modules arranged in two dimensions, an optical film, and an image display device; Its single light source module consists of a white surface-emitting solid-state light source, which excites a yellow phosphor containing green and red light and mixes the blue light to obtain white light, and an optical element that narrows the divergence angle of the diverging beam of the white surface-emitting solid-state light source. The aforementioned image display device directs a white light beam emitted from a light source unit onto the image display device and adjusts the intensity of the light according to the image signal to display an image on the screen; The aforementioned light source module has a cylindrical hole designed near the focal point of the reflective optical element end face to reflect the beam of light emitted by the white surface-emitting solid light source into almost parallel light through the reflective surface. The white surface-emitting solid light source is installed in the hole. The aforementioned optical film is placed between the light source unit and the image display device. Light from a specific polarization source can selectively enter the cylindrical lens designed on the image display device side of the optical film. A reflective polarizer is attached to the light source unit side of the aforementioned optical film.

8. A vehicle information display device and system with a solid-state light source according to claim 6 or 7, characterized in that: The cylindrical lens designed on the primary side of the aforementioned optical film image display device has an angle of inclination relative to the pixels of the image display device, with the lens in the vertical direction corresponding to its long side.

9. A vehicle information display device and system with a solid-state light source according to claim 8, characterized in that: The tilt angle of the cylindrical lens designed on one side of the image display device of the aforementioned optical film, corresponding to its long axis direction in the vertical direction of the image, is more than 5 degrees relative to the pixel of the image display device.

10. A vehicle information display device and system with a solid-state light source according to claim 7, characterized in that: The aforementioned optical film is disposed between the light source unit and the image display device. A cylindrical lens is provided on the image display device side of the optical film. P-polarized light can selectively enter the cylindrical lens. A reflective polarizer is attached to the primary side of the light source unit of the optical film to reflect S-polarized light.

11. A vehicle information display device and system with a solid-state light source according to claim 7, characterized in that: The aforementioned optical film is disposed between the light source unit and the image display device. A cylindrical lens is provided on the image display device side of the optical film. The cylindrical lens has no anti-reflection film on its surface. P-polarized light from the light source can selectively enter the cylindrical lens. A reflective polarizer is attached to the light source unit side of the optical film to reflect S-polarized light.

12. A vehicle information display device and system with a solid-state light source according to claim 5, characterized in that: The light source device has a light source unit composed of multiple individual light source modules arranged in a two-dimensional manner, and each individual light source module needs to be molded from heat-resistant plastic material.

13. A vehicle information display device and system with a solid-state light source according to claim 12, characterized in that: The light source device described above requires that each light source module be made of heat-resistant plastic with a heat resistance temperature of 120 degrees Celsius or higher.

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