JP2020510236A - Split exit pupil head-up display system and method - Google Patents

Abstract

Split exit pupil (or split eyebox) head-up display (HUD) systems and methods. The HUD system method of the present invention utilizes a split exit pupil design method that allows for a modular HUD system, allowing the field size of the HUD system to be adjusted while reducing the overall HUD volume aspect. The HUD module utilizes a high brightness, small size, micropixel imager to generate (one) or multiple HUD virtual images with one (1) or multiple given view box segment sizes. A number of such HUD modules that display the same image when integrated into a HUD system have an integrated HUD that has an eyebox size that is substantially larger than the eyebox size of the HUD module that enables such display. Provide the system. The volume of the resulting integrated HUD system is substantially smaller than that of a HUD system using a single larger imager. In addition, the integrated HUD system may consist of multiple HUD modules to scale the eyebox size to fit the intended application while maintaining the brightness of a given desired total HUD system. it can.

Description

  The present invention relates generally to a head-up display (HUD), and more particularly, to an image forming apparatus for a HUD system that generates one or more virtual images.

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B. H. Walker, Optical Design of Visual Systems, Tutorial tests in optical engineering, published by the International Society of Optical Engineering, Optical Society. 139-150, ISBN 0-8194-3886-3, 2000, C. Guillaux et al, Varilux S Series Breaking the Limits [18] Born, Principles of Optics, 7th Edition, Cambridge University Press 1999, Section 5.3, pp. 236-244,

  As a visual aide technology that contributes to vehicle safety by making the driver of the vehicle more visually aware, notifying the driver's gaze and notifying the dashboard information of the vehicle without paying attention to the road, There is a need for a head-up display. However, currently available heads-up displays are bulky and too expensive to be a viable option for use in most vehicles, and in applications for heads-up displays in aircraft and helicopters, cost factors Are smaller, but these same obstacles are encountered. For head-up display automotive applications, volume and cost constraints are further exacerbated by a wide range of vehicle sizes, types and cost requirements. Accordingly, there is a need for a low cost, non-bulk head-up display suitable for use in small vehicles such as automobiles, small aircraft, and helicopters.

  Prior art HUD systems can generally be grouped into two types: pupil imaging HUDs and non-pupil imaging HUDs. Typically, the pupil imaging HUD includes an optical system configured of a relay module, which causes transmission of an intermediate image and pupil formation, and a collimation module. The collimation module of the pupil imaging HUD is typically implemented as a slanted curved or planar reflector or holographic optical element (HOE). The relay module is typically tilted to bend the optical path to compensate for optical aberrations. Non-pupil imaging HUD defines the system aperture by the light cone angle or the intermediate image position in the display. In an intermediate image HUD system, a relay module is also required, but the HUD aperture is determined only by the collimating optics. Collimating optics typically have axial symmetry, but have folding mirrors to meet the required volume constraints. This is determined by the need for aberration correction and the volume aspect of the system.

  The prior art described in Ref [8] shown in FIG. 1-1 uses a collimating optical system as a concave hoe reflector (using (1) in FIG. 1-1) and a collimator. And reduce the volume aspect of the HUD system. The resulting HUD system requires complex tilt relay optics ((10) in Figure 1-1) to correct aberrations and deliver intermediate images. In addition, the HUD system has a narrow spectrum. Only works for

  The prior art described in ref [9] shown in FIG. 1-2 uses a relay optics (REL) module, and a converging coupler (CMB) mirror (cmb in FIG. 1-2). (Providing an intermediate image at the focal plane of the lens). The cmb mirror focuses the system pupil on the observer's eye to collimate the intermediate image and facilitate observation. This pupil imaging HUD approach necessarily involves complex rel modules for packaging and aberration correction.

  In the prior art described in Ref [10] shown in FIG. 1-3, an intermediate image is projected using a projection lens (3) on a diffusion surface (projected on the diffusion surface (51) in FIG. 1-3); And a translucent collimating lens ((7) in FIG. 1-3). The collimating lens forms an image at infinity, and the aperture of the collimating optics is defined by the angular width of the diffuser.

  The prior art shown in FIGS. 1-4 uses an image forming source consisting of two liquid crystal displays (LCDs). A panel (23 in FIG. 1-4) displays an intermediate image on a diffusion screen (FIG. 1-4). (5) is disposed on the focal plane of the collimating optical module (1 in FIG. (1-4)). The main purpose of the two LCD panels in the imaging source is to achieve sufficient brightness for the visibility of the formed image. To this end, the two LCD panels of the imaging source are: Side images, characterized in that they are configured to form two consecutive side faces t, are characterized in that they are arranged to be shifted one above the other in the horizontal and vertical directions by half a pixel of the diffusing screen. To be

  The prior art described in Ref [12] implements holographic dispersion correction (using a pair of reflective holographic optics (HOE)) and projects a virtual image of a broadband display source within the field of view of the observer. The prior art described in Ref [13] also uses a pair of holographic optical elements (HOE), one of which is transmissive and the other is reflective, which renders an image on a vehicle windshield. Project

  The prior art described in ref [14] shown in FIGS. 1 to 5 uses an image projector (shown in FIGS. 1 to 5) for a vehicle windshield configured to project an image. On the top surface, a facet-reflecting surface (attached to a vehicle dashboard with facet-reflecting surface (18) in figure (1-5)) configured to reflect an image from an image projector onto the windshield of the vehicle Have been. The vehicle windshield surface is oriented to reflect the image from the dashboard facet reflective surface toward the viewer

  The briefly described prior art HUD system and many others described in the cited prior art are the high cost and large volume size of the system. In addition, none of the discovered prior art HUD systems can increase size and cost in order to match the size and price range of a wide range of vehicles and other vehicles. Accordingly, it is an object of the present invention to provide a head-up display using multiple light-emitting microscale pixel array imagers to achieve a HUD system having a substantially smaller volume than a HUD system using a single imaging source. Is to introduce a method. It is an object of the present invention to provide a modular HUD system with volume and cost aspects that can be scaled to fit a wide range of vehicles and small vehicle sizes and price ranges. And a new split exit pupil HUD system design method utilizing the light emitting microscale pixel array imager. Further objects and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES
In the following description, similar reference numbers are used for similar elements in different drawings. Matters defined in the description, such as detailed structures and design elements, are provided to aid a comprehensive understanding of the exemplary embodiments. However, the present invention is not particularly limited, but the present invention can be implemented. In other instances, well-known functions or constructions are not described in detail as they may obscure the present invention in unnecessary detail. For a better understanding of the invention and how it may be implemented, certain embodiments of the invention are described by way of non-limiting example with reference to the accompanying drawings.

1 shows a prior art head-up display (HUD) system. The HUD system uses concave hoe reflectors as combiners and collimators to minimize collimation optics and reduce the volume aspect of the HUD system. A prior art head-up display (HUD) system using relay optics (REL)) module provides an intermediate image at the focal plane of a converging combiner (CMB) mirror and defines the system pupil. FIG. 3 shows a prior art head-up display (HUD) system using a projection lens. (3) Project an intermediate image as an image source on a diffusing surface. A prior art head-up display (HUD) system that uses an imaging source composed of a liquid crystal display (LCD) (shown in a panel) displays an intermediate image on a diffusing screen located at the focal plane of a collimating optics module. Form. Using an image projector configured to project an image onto a vehicle dashboard with faceted reflective surfaces using an image projector mounted on top of a screen (showing a prior art head-up display (HUD)) A system configured to reflect an image from an image projector onto a windshield of a vehicle. FIG. 1 illustrates an exemplary modular HUD (MHUD) system of the present invention. FIG. 3 is a diagram illustrating a relationship between design parameters and constraints of the MHUD system of FIG. 2. FIG. 3 illustrates an optical design surface and a ray trace diagram of a HUD module including the MHUD assembly of the embodiment of FIG. 2. FIG. 3 illustrates the optical performance of a HUD module including the MHUD assembly of the embodiment of FIG. FIG. 3 is a cross-sectional perspective view of an MHUD assembly design example of the MHUD system of the embodiment in FIG. 2. 3 shows a functional block diagram of the interface and control electronics design elements (boards) of the MHUD system of the embodiment of FIG. 2; FIG. 3 illustrates a novel split eyebox design method for the MHUD system of the embodiment of FIG. FIG. 3 shows the actual volume of the MHUD assembly design example shown in the figure installed on the dashboard of the subcompact vehicle. Fig. 3 shows the ray paths of the MHUD system of the present invention including the solar load Drawing an odd number of rows of pixels having an output that produces a first image, showing a front view and a side view of a solid state light emitting pixel array imager (ie, display element) in an embodiment of the multi-image HUD system of the present invention; Depicting the even rows of pixels having an output that produces a second image that is projected substantially downwardly with respect to the first image. The front and side views of the solid state pixel array imager in an embodiment of the multi-image HUD system of the present invention show a solid state pixel array imager (ie, showing pixels in the upper region of the display element) as described above. 2 has an output for generating the second image, and a pixel in a lower region of the solid-state light emitting pixel array imaging device having an output for generating the first image as described above. FIG. 3 is a diagram illustrating a plurality of ray paths of an embodiment of the multi-image HUD system of the present invention. FIG. 4 is a diagram illustrating the nominal positions of a near-field virtual image and a far-field virtual image in a low-volume package design in an embodiment of the multi-image HUD system of the present invention installed on a dashboard of a subcompact vehicle. 1 is a side view of a display element of the present invention including a plurality of non-telecentric refractive micro-optical elements. FIG. 2 is a side view of a display element of the present invention including a plurality of tilted refractive micro-optical elements.

  Reference to "one embodiment" or "an embodiment" in the following detailed description of the invention means that there is a particular feature in at least one embodiment of the invention. Structures or characteristics described in connection with are included. The appearances of the phrase "in one embodiment" in various places in this detailed description are not necessarily referring to the same embodiment.

  Recently, a new class of emissive microscale pixel array imagers has been introduced. These devices feature high brightness, very fast polychromatic light intensity and spatial modulation capabilities in a very small single device size that includes all the necessary image processing drive circuits. The solid state light (SSL) of one such device may be either a light emitting diode (LED) or a laser diode (LD)). The off state is the light emitting microscale of the imaging device. pixel. The array is controlled by a drive circuit contained within the cmos chip (or device) to which it is coupled. The size of the pixels that make up the light emitting array of such an imager is typically in the range of about 5-20 microns, and the typical light emitting surface area of the device is in the range of about 15-150 square millimeters. . Luminescent microscale. pixel. array. Pixels within the device are individually spatially, chromatically and temporally addressable, typically via the driver circuitry of the cmos chip. The brightness of light generated by such an imaging device can reach a plurality of 100,000 cd / m2 with moderately low power consumption. One example of such a device is the QPI imager (see Ref [1-7]) referenced in the exemplary embodiment described below. However, it should be understood that a QPI® imager is merely an example of the type of device that can be used with the present invention. “QPI” is a trademark of Ostedo Technologies, Inc. Is a registered trademark of Microsoft Corporation. In the following description, any reference to a QPI® imager should be understood to be for specificity in the present invention. For purposes of limiting the present invention, the disclosed embodiments are disclosed as a specific example of a solid state light emitting pixel array imaging device (hereinafter simply referred to as an "imaging device") that can be used.

  The present invention relates to a low cost, compact modular HUD (which combines the inherent capabilities of such a light emitting micro-pixel array device of an imaging device with a novel split exit pupil HUD system architecture to achieve MHUD), such as a vehicle HUD. And a system that can be easily used for applications where cost and volume constraints are parametric. The combination of a light emitting high brightness micro-emitter pixel array of an imager, such as a QPI® imager, with the split exit pupil HUD architecture of the present invention enables a HUD system to operate effectively in high brightness ambient sunlight, and Volumetrically small enough to fit behind dashboards or instrument panels in a wide range of vehicle sizes and types. As used herein, the term "vehicle" is used in its most general sense and includes, but is not limited to, any means by which someone travels, on land, in water, in water and in air. Including moving. The low cost and modularity of the split exit pupil HUD architecture enabled by such an imager allows for a modular HUD system that can be tailored to accommodate a wide range of vehicle volume constraints. The virtualization of the split exit pupil HUD system will become more apparent from the detailed description provided herein within the context of the embodiments described in the following paragraphs.

  FIG. 2 illustrates a design concept of a modular HUD (MHUD) system according to an embodiment of the present invention. In a preferred embodiment, as shown, the MHUD system (200) of the present invention is comprised of an MHUD assembly (210), wherein the MHUD assembly (210) is assembled together to form an MHUD 210. Each module (215) is composed of a single imager having an associated optical system (220) and a concave mirror (230), and as shown in FIG. Images emitted from each single imager having (220) are collimated, magnified and reflected by its associated concave mirror (230), partially reflected from the vehicle windshield (240) and displayed. Eyebox segment located at the nominal head position of the driver of the vehicle that is within the range of forming a possible virtual image (260) 255)), each module (215) of the MHUD assembly (210) is arranged to form the same virtual image (260) at once and at the same location as the vehicle windshield (240). Of each corresponding eyebox segment (255) such that multiple modules (215) of the MHUD assembly (210) collectively form the collective eyebox (250) of the MHUD system (200). Corresponding to each. That is, the virtual image (260) is partially visible from each of the eyebox segments (255), but is fully visible in the aggregated eyebox (250), and the eyebox segment of the MHUD system (200). The overall size of (255) can be adjusted by selecting an appropriate number of modules (215) that make up the MHUD assembly (210), multiple eyebox segments and modules are user definable. It is characterized by the following. Each module (215), including each module (215) of the MHUD assembly, 210 is arranged to form the same virtual image (260) at any one time, and of course, these images may change over time. Configured to display the image, such as in the display of a display image of a gps navigation system, which may change slowly, such as a fuel gauge image, or may change more rapidly. The MHUD system of the present invention is capable of operating at frequencies up to at least typical video rates when image data is available at such rates.

  In a preferred embodiment of the MHUD system (200), the eyebox segments (255) of the module (215) of the MHUD assembly (210) are respectively located at the exit pupils of the light bundle reflected by the corresponding concave mirror (230). The collective eyebox (250) of the existing MHUD system (200) is a split exit pupil eyebox formed by the overlap of the eyebox segments (255) of the module (215) of the MHUD assembly (210). The split exit pupil design method of the MHUD system of the present invention is described in further detail in the following paragraphs.

  In a preferred embodiment, the MHUD system of the present invention and the MHUD system of the present invention comprise a MHUD assembly comprising a number of modules assembled together to form an MHUD assembly, each module comprising a QPI® Consisting of an imaging device, such as an imager, or other suitable light emitting structure, such as an oled device having associated optics and a concave mirror. The method of designing the MHUD assembly of the MHUD system of this embodiment of the present invention and its respective modules are described in more detail in the following paragraphs, preceded by a description of the relevant advantages of the MHUD system of the present invention and the trade-offs of the relevant design parameters. It is explained in.

MHUD System 200 Optical Design Parameter Tradeoffs
Parameters that are considered important to explain the basic design trade-offs of a typical HUD system, and the relationship between its associated designs, in order to understand the advantages of the MHUD system of the present invention. A HUD system that generates a virtual image generated by the virtual image generation unit t typically has a viewer operating a vehicle visually recognizing an operation parameter of the vehicle, such as a navigation system. It is intended to provide important information such as information without being superimposed on natural scenes, and to be able to draw attention from around the road and outside of the vehicle Important parameters to consider in the design of the HUD system include the target size of the collective eye box, the desired field of view (FOV), the formed virtual image size, the virtual image resolution, and the system volume constraints. Including. FIG. 3 shows the relationship between these design parameters and constraints.

Method for implementing modular HUD (MHUD) reduced volume of the present invention
Referring to FIG. 3, reducing the size of the MHUD system 200 imager 220 leads to a smaller effective focal length (EFL)), which is a characteristic optical track length of the system and generally contributes to a reduction in system volume. I do. However, if the eyebox size is maintained, reducing the imager aperture size will result in a lower system f / # with increased optical complexity. This generally refers to the design concept of the MHUD system shown in FIG. 2, which results in greater system capacity. The size of the eyebox segment (255) for each module 215 is to avoid increasing optical complexity. The size of the imager (220). This results in a scaling of the volume of each of the modules (215) by the size ratio of the imager (220). A number of modules (215) combine to form an MHUD assembly (210) that can provide a collection eyebox (250) of any size. The novel multi-segment eyebox design concept of the MHUD system (200) of the present invention is realized by dividing the exit pupil of the system formed in the viewer's eyebox into multiple segments. This corresponds to (one) of the eyebox segments (255) that constitute the collection eyebox (250) of (200). Thus, the split exit pupil design method of the MHUD system (200) of the present invention achieves a smaller overall volume surface than prior art HUD systems that provide the same size eyebox. This leads to a reduction in overall HUD volume, complexity and cost. Other advantages of the disclosed split exit pupil design method of the MHUD system (200) of the present invention are described in the following description. Of course, each module emits the same image at any one time, so that the vehicle operator will see the same virtual image at the same location, independent of each eyebox segment (255) or eyebox segment (255). Then, it is configured so that the operator can see it.

A major factor for the volume of prior art HUD systems that use a mirror reflector ref [8-10] has been identified as a concave mirror. In addition to the large size of the mirror itself, the size of the image source is proportionately large, which may dictate the use of a large imager or form a large intermediate image projected on a diffusing screen. it can. projector. Add more volume to incorporate the imager and its associated projection optics. As explained in the preceding description, the MHUD system of the present invention achieves a plurality of features that achieve substantially smaller volumetric surfaces than prior art HUD systems that use a single concave mirror as the main reflector. Using an MHUD assembly (210) composed of modules (215), 235 using a small concave mirror (230) assembled together to form an overall reflector, the MHUD assembly (210) Among them, the size is much smaller and achieves much smaller optical track length. An MHUD assembly using a smaller aperture size imager allows the use of smaller aperture size concave mirrors, thereby having a smaller optical track length,
Substantially small volume and volume efficient MHUD system of the present invention

  The design of the MHUD system of the present invention works by splitting a large collimated beam that would typically be created by a single large mirror, in an exemplary embodiment three equal sized collimators Sub beam. Each sub-beam is generated by the optical subsystem of module (215), which results in reduced F #, optical complexity and focal length (EFL) (or optical track length), so that: The physical volume envelope of the system is reduced. As shown in FIG. 4, the module (215) of the preferred embodiment, showing the optical design surface and ray tracing of the module including the MHUD assembly, includes (one) with associated optics (220) and concave mirror (230). In the embodiment shown in FIG. 4 comprising an imager of the present invention, the optical system (420) associated with the imager (410) is shown as a separate lens optic, another embodiment of the present invention. In embodiments, the imager-related optics may be mounted directly on top of the light-emitting surface of the imager, as shown, to form an integrated imager assembly, each module (215) In the reflective concave mirror (230), the image generated by the corresponding imager (or other imager) (220) is Forming a eyeboxes segment (255), FIG. (4) optical element (420) associated with the imaging device (410) of the balance the off-axis distortion and tilt aberration resulting from the reflection concave mirror (230).

FIG. 5 illustrates the optical performance of the module of the MHUD assembly, as shown in FIG. The reflective concave mirror (230), which is to balance, is such that the image swimming effect is typically reduced to a minimum, while maintaining the modulation transfer function (MTF) at a sufficiently high level. Prevents optical distortion due to mirror aberrations caused by a change in the direction of light incident on the observer's pupil due to t, and allows perceived spurious perception of virtual images (known as "swimming effects"). Movement), causing the observer's head to move (or gaze) within the HUD system eye box [Ref6].
It is very important to minimize swimming effects in binocular optical systems such as HUDs, and in extreme cases, excessive swimming effects in virtual images can lead to motion sickness in the human visual system. Vertigo or nausea caused by competition between the vestibular and perceptual systems, the vestibular and octuple motor aspects of Ref [16, 17].

  Another advantage of the split exit pupil method of the MHUD system of the present invention is that it achieves a substantially reduced swimming effect compared to prior art HUD systems that use a single mirror with a larger optical aperture. That is. The aberration of the smaller optical aperture of the reflective concave mirror (230) is much smaller than the aberration of the relatively large optical aperture reflective mirror used in prior art single mirror HUD systems, and the swimming effect is directly proportional to the size of the light. The distortion (or ray direction deviation) due to aberrations arising from the reflecting HUD mirror, the large number of miniature optical aperture concave mirrors (230) of the MHUD system (200) of the present invention is substantially less than prior art HUD systems. To achieve a small swimming effect. In addition, the angular overlap between the eyebox segments (255) of the MHUD module (215) can be used to determine the perception of any point in the virtual image 260 described in more detail in the description of FIG. As a result of incorporating the optical contribution from 215), the optical distortion (or ray direction shift) aberrations of the individual concave mirrors (230) of the plurality of MHUD modules (215) can be adjusted at any point in the virtual image 260. , Resulting in a reduction in the overall swimming effect perceived by a viewer of the MHUD system (200).

  In another embodiment of the present invention, the imager of the MHUD assembly has a higher residual resolution than the human visual system (HVS) in a typical HUD viewing experience due to aberrations arising from the concave mirror (230). A virtual image can be solved at an additional resolution dedicated to digital image warping for optical distortion pre-compensation, with a Hvs lateral vision of about 200 microradians formed at a distance of about 25 m. At such a distance, hvs can resolve approximately 2500 x 0.0002 = 0.5 mm pixels, which corresponds to a resolution of approximately 450 x 250 pixels for a virtual image (260) with a 10 "diagonal. The imager (220) used in the MHUD assembly (210) can provide a much higher resolution than this limit, for example, providing a 640x360 resolution or an even (1280x720) with the same size optical aperture. An imager (220) that provides a higher resolution with the same size optical aperture allows the use of a concave mirror (230) with the same size optical aperture, thereby allowing the MHUD assembly (200) to be used. Added imager (220) that can maintain volumetric advantages The image resolution enables the use of a digital image pre-warping compensation that virtually eliminates the optical distortion due to the concave mirror (230) and the resulting swimming effect while maintaining the maximum achievable virtual image (230). 260) resolution and same volume advantages.

  Each of the reflective concave mirrors (230) may be aspherical or free-shaped, such that the concave mirror (230) whose aspherical surface or aspherical coefficient is the aspherical or free-form factor of the lens t is The position of each imager (220) selected to minimize the optical aberrations of the concave mirror (230) and, if necessary, to minimize the curvature of the windshield is determined by its associated concave mirror (230). Note that this is preferably axially symmetrical to ensure optimal balance (somewhat equal).) An important design aspect of the MHUD system (200) of the present invention is The MH of the present invention assures a uniform view transition of the virtual image (260) between the plurality of eyebox segments (255) of the collection eyebox (250) of the MHUD system (200). An important design aspects of the UD system (200)

  FIG. 6 shows a multi-faceted perspective view of the MHUD assembly, as shown in FIG. 6, wherein the MHUD assembly (210) is comprised of three reflective concave mirrors (230) assembled together in an enclosure 600; The three concave mirrors (230) may be made separately and mounted together within the housing 600, or may be manufactured as a single piece mounted within the housing 600. The three concave mirrors (230), whether assembled separately or as a single optical component, can be manufactured using an embossed polycarbonate plastic whose optical surface is coated with a thin layer of reflective metal. A material such as silver or aluminum can be used by using a sputtering technique. As shown in FIG. 6, the rear side wall of the housing is composed of three separate sections (610), each section (610) having a rear side wall (610) with a respective concave mirror (230). When assembled, they are positioned to coincide with the optical axis of (230), including the optical window (615), and as shown in the side view of FIG. 6, the optical axis of each concave mirror (230). 6, the upper edge (617) of each back side wall (610) is inclined toward the concave mirror (230) to enable the imager (220). It is mounted on the inclined end surface (617) of the section (610) and is configured to coincide with the optical axis of each concave mirror (230).

  As shown in the rear side view of FIG. 6, the back side wall portion includes control and interface electronics (assembled together on one side of the back plate with printed circuit board) (620) and the back plate. The back plate (630) also incorporates thermal cooling fins to interface the imager (220) and the MHUD assembly (210) with the MHUD assembly (210) mounted on the opposite side of the (63030). Each imager is typically mounted on a flexible electrical board that connects the imager to control and interface electronics, as shown in the rear view of FIG. 6, which dissipates the heat generated by the element (620).

  As shown in the rear side view of FIG. 6, the center of the interface end of each pair of concave mirror (230) and back side wall (610) may incorporate a photodetector (PD) (640), typically. Are photodiodes, each including a respective concave mirror (230) positioned and oriented to detect light emitted from the imager (220) on t (s); Typically, three photodiodes are used in each module, one for each color of light (one) is used to control the output of the photodetector (PD) (640) and the MHUD assembly (210). Realized in the hardware and software design elements of the interface electronics (620) that are connected to the interface electronics (620) and used as inputs to the uniformity control loop (described below). Also provided as input to the control and interface electronics (620) of the MHUD assembly (210) is the output of the ambient light detector sensor (660), which is typically Is an integral part of the vehicle dashboard brightness control.

  The control and interface electronics of the MHUD assembly incorporates the hardware and software design functional elements shown in the block diagram of the MHUD interface function (710), the control function (720), and the uniformity loop function (730). The control and interface of the MHUD assembly (210) including the MHUD interface function (710) of the electronics (620), typically implemented in a combination of hardware and software, includes a vehicle driver assistance system (DAS). ) Receives the image input (715) from the control unit (720) and incorporates the color and brightness correction (735) provided by the control function (720) into the image to convert the image input (744), (745), (746) into the MHUD assembly. Provided to (210) imager (220) The same image input 715 data can be provided to the three imagers (220) of the MHUD assembly (210). The MHUD interface function (710) receives each imager (220) from the control function (720). Based on the color and brightness corrections (735), include specific color and brightness corrections in the respective image inputs (744), (745), and (746).

  The uniformity loop function (730) of the control and interface electronics (620) converts the input signal (754) to ensure color and brightness uniformity over multiple segments (255) of the collective eye box (250). Calculating the color and brightness from the photodetector (PD) (640) of each module (215) of the MHUD assembly (210) to receive, the module of each MHUD assembly then calculates the color and brightness Calculate the necessary color and luminance corrections to be more uniform across multiple segments of the collective eyebox. This is as follows. This is accomplished when the MHUD assembly (210) is first assembled using an initial calibration look-up table that is executed and stored in the memory of the control and interface electronics (620). The color and brightness corrections calculated by the uniformity loop function are then provided to the control function, which receives these corrections from the ambient light sensor and the external color and brightness adjustment input commands. Generating a color and brightness correction (735) to be incorporated into the image data by the MHUD interface function (710) before the corrected image data associated with the input is provided as an image input (744); Incorporating the input received from (650) into the color and brightness corrections, the control function (720) determines the brightness of the virtual image of the heads-up display in proportion to the brightness of the ambient light of the vehicle. Or in relation to it. As used herein, image data is either received as input to a heads-up display, such as provided to an imaging device, or is received in any other form. Note that the image information has the following form.

  As described above, one embodiment of the MHUD system uses an imager having a resolution higher than the maximum hvs resolvable resolution in the virtual image and incorporates means for removing or substantially reducing optical distortion. The MHUD interface function (710) of the MHUD assembly (210) of the existing MHUD system (200) is also incorporated into the MHUD interface function (710) of the MHUD assembly (210) of the MHUD system (200). The MHUD interface function (710) includes a plurality of look-up tables that include data identifying digital image warping parameters needed to pre-compensate for residual optical distortion of each concave mirror (230), where these parameters are t Featured to be used The MHUD interface function (710) warps the digital image input of each imager (220) such that the image data input to each imager (220) pre-compensates for the residual distortion of the corresponding concave mirror (230). The digital image warping parameters incorporated in the look-up table of the MHUD interface function (710) functioning in advance are generated in advance from an optical design simulation of the MHUD assembly (210), and the digital image pre-warping compensation is performed by the MHUD interface function (710). ) Is extended with optical test data based on measurements of the residual optical distortion of each module (215) after being applied. The resulting digitally distorted image data is then combined with the color and brightness corrections provided by the control function as image inputs (744), (745), (746) as image inputs (744). ), (745), and (746) are provided to the imaging device (220) of the MHUD assembly (210). In the design method of the MHUD system (200), the residual optical distortion and the resulting swimming effect due to the concave mirror (230) can be substantially reduced or completely eliminated, and the distortion-free MHUD system (200) can be used. 200)

  As shown in the perspective view of FIG. 6, on the upper side of the MHUD assembly is a glass cover 430, the optical interface of the MHUD assembly (210) at the top of the vehicle dashboard. The glass used, which acts as a window and attenuates sunlight infrared light and prevents the heat load of sunlight in the imager (220), is substantially used for the wavelength of light of interest. Should be selected to be transparent.

  The method of designing the MHUD assembly (210) takes advantage of the characteristics of the human visual system (HVS). To simplify the design implementation and assembly tolerances of the MHUD assembly (210), first the pupil of the eye is Observing the virtual image (260) with a diameter of about 5 mm ((3-5 mm during the day, 4-9 mm at night)), the resulting lateral vision is about 1 mm wide with the MHUD assembly (210). It allows for a non-discriminatingly small gap between the concave mirror (230) that can be reached. Second, the accommodation limit for an eye angle difference of about 0.5 degrees allows for a small angular tilt between the MHUD assembly and the concave mirror, which can reach about 0.15 degrees. These tilt and gap tolerances show significantly relaxed mechanical alignment tolerances for the MHUD assembly 210 concave mirror 230, thus enabling a very costly manufacturing and assembly method for the MHUD assembly (210). I do. Any additional tilt and / or alignment requirements can usually be easily accommodated in software.

  FIG. 8 shows a novel divided eyebox design method of the MHUD system of the present invention. FIG. 8 is meant to show the relationship between the collective eye box (250) and the virtual image (260) of the MHUD system (200). FIG. (8) shows an exemplary object (810), and the arrow shown in the virtual image (260) is displayed by the MHUD system (200). In the design of the MHUD system, each of the eyebox segments is typically located at the exit pupil of its respective module, and the image information presented to the viewer's eyes in each eyebox segment 255 is represented by an angle In space. Thus, the virtual image 260 arrow object presented to the viewer in each eyebox segment 255 typically shows to the viewer when the viewer's head is located in the central region of each eyebox segment. The leading or trailing edge of the arrow object (810) of the virtual image (260) will be gradually vignetted (fade out) so that it becomes completely visible. Moving to the left, the module (215), each of the designs of the MHUD system (200), is integrated into the MHUD assembly (210), as shown in the perspective view of FIG. 6, as shown in FIG. , The eye box segment (255) of the module (215) is overlapped, and the collective ivoc of the MHUD system (200) The production of (250). Thus, the collective eyebox (250) of the MHUD system (200) is viewed in the entire eyebox 250, formed by the overlap of the exit pupil areas forming the eyebox segments (255) of the plurality of modules (215). As shown in FIG. 8, the image information presented to the human eye is an angle multiplexed view of a virtual image (260) extending over the combined angular field of view of the MHUD module (215). , The arrow object (810) of the virtual image (260) is such that the arrow object (810) of the fully visible (or visible) virtual image (260) gradually becomes vignetting (or fading). Overlap area of eyebox segment (255) defining aggregate eyebox (250) of (200) Is moved to the right or left of the peripheral area of the collective eye box (250), the observer's head is moved to the right or left of the peripheral area of the collective eye box (250). It is characterized by the following.

  The size of the overlap between the module's eyebox segments 255 determines the ultimate size of the collective eyebox (250) of the MHUD system (200), depending on their angular vignetting profile in the figure, the latter being a virtual The image (260) is configured to provide the desired brightness uniformity (defined as the area boundaries or dimensions of the collective eyebox (250)) that is fully visible (or visible). Also, as shown in FIG. 8, a virtual image perceived by an observer (260) showing the angular vignetting profile shield resulting from the MHUD assembly over the entire area of the overlapping eyebox segments of the module. ) Includes the ar, ac, and al (left, center, and right) luminance contributions from each module (215), respectively. The criterion for defining the boundary of the set eye box (250) is that the luminance of the virtual image (260) within the area a of the overlap a of the eye box segments (255) and 255t is a predetermined threshold value λ (for example, (Less than 25%) is the desired uniformity threshold over a selected area, ie, VarA (AR + Ac + AL) ≦ λ. The perceived brightness across the virtual image, with the criterion for defining the boundary of the set eye box (250) and the overlap of the eye box segment (255) of the module (215) shown in FIG. , At least 50% of the modules. This means that somewhere within the boundaries of the collective eyebox defined by the defined criteria, each module (215) has at least 50% of the perceived brightness of the virtual image (260). To contribute. In this design approach for the MHUD system (200), the desired luminance uniformity of the virtual image (260) is a criterion that defines the size of the aggregate eye box (250), and this design criterion is shown in FIG. As shown in FIG. (8), a uniformity threshold λ = 37.5% is used to indicate that a 120 mm wide aggregate eye box (250) is manufactured using the uniformity threshold λ = 25%. , Define an approximately 25% wide collective eye box (250) measuring approximately 150 mm.

As shown in FIG. 8, the arrow object (810) of the virtual image, which is an eye box segment area extending beyond the left and right of the collective eye box of the MHUD system, moves the observer's head to these areas. At that time, gradually vignetting or fading out. In the design approach of the MHUD system (200), adding a module (215) to either the right or left side of the MHUD assembly (210) is shown in FIG. The arrow object (810) of the virtual image (260), which extends the width of the collective eye box (250) of the MHUD system (200), as defined by the design criteria defined earlier, has the desired brightness uniformity. When it becomes completely visible, the arrow object (810) of the virtual image (260) is made completely visible with the desired brightness uniformity. When another row of modules (215) is added to the MHUD assembly (210), a similar effect of extending the height of the collective eye box (250) occurs in the orthogonal direction. Thus, in the modular design method of the MHUD system (200) of the present invention, the present invention allows the collection eyebox (250) of any size with the selected width and height dimensions of any design to be more This can be achieved by adding a module (215) to the MHUD assembly (210).

  In essence, the split exit pupil module design method of the MHUD system of the present invention has relatively small apertures, each achieving a short optical track length, allowing the use of multiple imagers and concave mirrors. Can replace the much longer optical length of the larger image source and the single mirror used in prior art HUD systems. Thus, the smaller aperture imager and concave mirror of the MHUD module can be achieved by prior art HUD systems that use a larger single image source and a single mirror to achieve the same size eyebox. , Collectively allowing substantially smaller volumetric aspects. Further, the achieved size of the collective eyebox (250) of the MHUD system (200) can be adjusted by using an appropriate number of basic design elements of the modules (215). Conversely, the volume configuration of the MHUD system (200) can fit the same available volume that can be made to match the available volume in the dashboard area of the vehicle while achieving t. It provides a larger sized collective eyebox (250) that can be achieved by a state-of-the-art HUD system.

  To illustrate the volume advantages of the MHUD system of the present invention, the perspective view of FIG. 6 uses three imagers (220), shown at t in the figure, each with an optical aperture size of 6.4 × 3.6 mm. Brightness uniformity threshold of λ = 25%, comprising three concave mirrors, each having an optical aperture size of (60100 mm), which determines the design dimensions of the MHUD assembly (210) having Based on the above, a collective eye box 250 size of 120 × 60 mm is realized. Based on the design dimensions shown in FIG. 6, the total volume of the MHUD assembly is approximately 1.350 cc (1.35 liters) as follows: For comparison, the overall volume of a prior art HUD system using a single large aperture mirror is that a single larger image source to achieve the same eyebox size with (one) t is: Over 5000cc (5 liters). Therefore, the design method of the MHUD system (200) of the present invention is a HUD system that is a factor of volumetric efficiency (or smaller) than the prior art HUD system. To visualize this three-dimensional advantage, FIG. 9 is shown in FIG. 6 installed on the dashboard of a subcompact vehicle showing the volume of the design example t of the MHUD assembly. As shown in FIG. 9, the volumetrically efficient design of the MHUD system of the present invention makes it possible to add HUD functionality in vehicles with very constrained dashboard volumes where prior art HUD systems simply do not fit. to enable.

  FIG. 10 shows the ray paths of the MHUD system as shown, and the three imagers (220) with the MHUD assembly (210), already described and shown in FIG. 2, each have the same resolution ( Three concave mirrors after being reflected by three concave mirrors (230), after being reflected by three images, after being reflected by three concave mirrors (230) that generate the same image at 640 × 360 pixels) After being reflected at (230), the entire 120 × 60 mm set eye box (250) of the previously described design example will be angularly addressed, and the 125 × 225 mm virtual image of the previously described design example will be addressed. Collectively provide 640x360 spatial resolution over (260).

  FIG. 10 shows the design requirements for producing 10,000 cd / m 2 brightness in a virtual image, which is typical of a windshield reflectivity of about 20% and the collective eyebox described above. Each of the three imagers (220), with 250 boundary definition criteria, produces a luminance of about 25,000 cd / m2. A prior art HUD system in which the three imagers (220) and the control and interface electronics (620) of the MHUD assembly (210) collectively consume about 2w and produce a brightness of 25,000 cd / m2. Power consumption is about 25%.

  Referring to the performance of the MHUD system shown in FIG. 5, the enclosed energy plot of FIG. 5 shows the geometric blur radius of the collimated light beam from the optical aperture of the concave mirror (230) of size 180 microns. Show. Each module (215) designs the example shown in FIG. 6 with an effective focal length of 72 mm. The magnitude of the 180 micron blur shown in the enclosed energy plot of FIG. The 0.143 deg for the light beam generated at the pixel of the imager (220) that provides the spread and the light beam collimated by that light beam, the corresponding concave mirror (230) is 0.1 mm for the total beam width from the pixel. A swimming effect associated with an angular spread of 143 °, where the resolution (MTF) is determined by the effective beam width sampled by the eye pupil size. The MTF plot of FIG. 5 shows the MTF of each module calculated for a typical eye pupil diameter of diameter. The smaller the angle spread angle, the smaller the swimming radius of the virtual image (260) in the virtual image (260). For m from the collective eyebox of the MHUD system, the corresponding swimming radius of the MHUD system design example is 62 mm. Having an optical aperture size equal to the full aperture size of the prior art HUD system MHUD assembly (210) using a single mirror and 2t, the design example is about 2 / 4x larger than the optical aperture of the module (215). It will have a large optical aperture. Prior art single mirror HUD having an optical aperture size equal to the full aperture size of the MHUD assembly (210) design example, wherein the magnitude of the aberration blur is directly proportional to the aperture size raised to the third power Ref [18]. The system has a corresponding swimming radius of about 14.3 mm. If fifth order aberrations occur to compensate for large third order aberrations that cannot be intentionally achieved by design, otherwise prior art single mirror HUD systems typically have a. The corresponding swimming radius is about 390.7 mm, which is 1.2 × larger than the swimming radius achieved by the design example (50t), but should also be mentioned using the previously described pre-aberration correction method. Certain, the swimming radius of the MHUD system (200) can be substantially reduced or even entirely eliminated from the stated values of this design example.

  FIG. 10 also shows the ray path of the MHUD system including the solar load. As shown in FIG. 10, the reverse optical path of sunlight colliding with the windshield of the vehicle can cause glare in the virtual image (260) in the design of the MHUD system (200) of the present invention reaching time t. The amount of sunlight that can reach the collective eyebox (250), including the potential collective eyebox (250) area, is much less than in prior art HUD systems. First, assuming that the windshield 240 light transmission is 80%, light rays from the sun are attenuated by the windshield (240) to a maximum of 80% of its brightness. Secondly, the transmitted sunlight through the windshield (240), while the reflected sunlight is further attenuated by the anti-reflection (AR) concave mirror to the corresponding imaging device 220) imaging device (220) The coating on the optical aperture of the lens ranges up to 5% of its brightness before being reflected towards the concave mirror 230 assembly. Third, this reverse path sunlight is further attenuated to at least 20% of its brightness as it is reflected by the windshield (240) toward the collective eye box (250). As described earlier, the imager and concave mirror of each module contributes up to 50% to the brightness of the virtual image, the glare of sunlight reflected from the module (215) defined by sunlight, , Is attenuated by 50% in the virtual image (260).

  Thus, based on this path attenuation analysis, sunlight arriving at the collective eye box is attenuated to a maximum of 0.4% (less than 1%) of its brightness. By enabling the MHUD system (200) to generate 10,000 cd / m2 brightness and 0.4% sunlight glare in the virtual image (260), the MHUD system (200) becomes more 000 cd / m 2, which corresponds to a unified glare rating (UGR) (or glare-to-image intensity ratio) of 250, about 28 db, which can tolerate much sunlight brightness. It should be noted that the glass cover (430) is infrared-absorbing, transparent to light of the wavelength used in the head-up display of the present invention, and the solar load heat is reduced by the concave mirror (230) to the imager. Returning to (220) prevents concentration.

  In the embodiments described above, a plurality of modules are arranged side by side to provide overlapping eyebox segments to provide a collective eyebox that is wider than eyebox segment 255 itself. However, if desired, alternatively or additionally, the module's eyebox segments can also be stacked to display the same virtual image, where the modules can be arranged to provide a higher collective eyebox. All of the modules are in the same position in front of the vehicle. Note that the stacking to provide a higher collective eyebox is generally not due to the stacking of modules, but rather to the inclination of the typical windshield. This can be achieved by simply using a larger, substantially horizontal area of the dashboard for the application.

Also, as mentioned earlier,
"As shown in FIG. 2, the image emitted from each single imager with associated optics is magnified and reflected by its associated concave mirror (230) and then the vehicle windshield ( 240) can be seen in the eyebox segment 255 located at the nominal head position of the driver of the vehicle, forming a virtual image 260 that is partially reflected. "

  In either embodiment, the degree of collimation achieved by the concave mirror is not necessarily perfect, but is intentionally set and intentionally set to limit the front of the vehicle where the virtual image is formed. Is also good. In some examples, the concave mirror may, in fact, be intentionally designed to actually distort the collimation and offset the next source of aberrations, if any. Another example is the curvature of the windshield.

  It has previously been shown that control and interface electronics (620) of the MHUD assembly (210) of FIG. 2 can provide for off-axis distortion and tilt aberrations and color and brightness correction (see also FIG. 6). ). Of course, the lateral position correction of each image or image segment from each module ensures that control and interface electronics 620 (which can also be performed mechanically) double images or double image portions are not displayed. Furthermore, it should be noted that "brightness correction" has at least the main aspects. The first and most obvious are brightness changes, module and module corrections so that the brightness (and color) of images from different modules does not differ. However, in connection therewith, the change in pixel spacing due to warpage is visible, which is related to the fact that image warping and other factors may possibly cause variations in the brightness of image parts within individual modules. Brightness aberration may occur. When this is encountered, the brightness of each individual pixel in each module is individually controllable, and in areas where pixel separation increases, the locally required pixel brightness can be increased and areas where pixel separation decreases Then it decreases. Finally, it should be noted that typical solid state light emitting pixel array imagers are typically rectangular with non-uniform dimensions, rather than square imagers. As a result, selection of the orientation of the imaging device can also provide additional variables that can be useful in designing the heads-up display of the present invention.

  Table 1 below shows the salient performance characteristics of the imager-based MHUD system of certain embodiments of the present invention, a prior art HUD system using a single larger mirror and a single larger image source. Demonstrate their performance advantages as compared to. As shown in Table 1, the split exit pupil MHUD system of the present invention enhances the prior art HUD system by a number of factors in all performance categories. It has also been eased. As mentioned above, the MHUD system of the present invention is expected to be much more cost effective than the prior art with comparable eyebox sizes.

Multi-image head-up display system with near-field and far-field virtual images
In many HUD system applications, it is desirable for the HUD system to display a plurality of virtual images to the viewer, preferably placed directly in front of the viewer, while simultaneously taking care of the viewer's attention from driving Provide secure visibility of additional information to avoid. In this context, for example, a first virtual image can be displayed at a far-field distance generally used in a conventional HUD system, and a plurality of virtual images can be displayed by a HUD system. A second virtual image is displayed. Preferably, both virtual images are visible to the HUD system viewer without requiring the viewer to leave the road, allowing the driver to continue to pay attention to driving conditions.

  In another preferred embodiment of the present invention of the present disclosure, the split exit pupil design architecture described above can be used in combination with multiple display elements, i.e., an imager and associated optics (220). As shown in FIG. 2, each display element (220) is configured to modulate a plurality of images at different output angles.

  In one aspect of the multi-image head-up display system of the present invention, the system comprises a solid state light emitting pixel array imager (i.e., can include a plurality of modules (215) with display elements) (220); Viewing the first and second images generated by the emissive pixel array imager (220) in an eyebox segment including a concave mirror (230) configured to expand and reflect toward (50t). It is configured to form possible first and second virtual images. The plurality of modules are arranged such that the eyebox segments (255) combine to provide a heads-up display such that each module (215) has a larger aggregated eyebox (250) than the eyebox segment (255). The collective eye box (250) is positioned to be at the nominal head position of the driver of the vehicle. In a first aspect of an embodiment of the multi-image head-up display system of the present invention, a solid state light emitting pixel array imager (220) includes a first set of pixels associated with a respective first set of micro-optical elements. , A second set of pixels associated with each second set of micro-optical elements. A first set of micro-optics is configured to direct output from each first set of pixels to generate the first image described above, thereby providing a collection eye box (250). A first virtual image is generated that can be viewed at a first distance from. The second set of micro-optics generates a second virtual image configured to direct the output from each second set of pixels to generate the second image described above, wherein the second virtual image is generated. Generates a second virtual image, the second virtual image is visible at a second distance from the first virtual image, and the micro-optics are substantially tilted with respect to the surface of the solid state light emitting pixel array imager. Non-telecentric lenses or non-telecentric optics configured to allow pixel output may be included.

  In a first aspect of the embodiment of the multi-image head-up display system of the present invention, the first distance may be a far-field distance and the second distance may be a near-field distance. The first set of pixels may be a user-defined first set of pixels of the solid-state pixel array imager, and the second set of pixels may be a user-defined set of pixels of the solid-state pixel array imager. It can be a second set. The first set of pixels can be an odd row of pixels of the solid state pixel array imager, the second set of pixels can be an even row of the solid state pixel array imager, The second set of pixels may be an even-numbered row of the solid state pixel array imager, and the first set of pixels may be an even-numbered row of the solid state pixel array imager. Preferably, the second set of pixels may be an odd row of the solid state light emitting pixel array imager (220). The first set of pixels may be pixels that make up at least 50% of the pixel area of the solid state pixel array imager (22), and the second set of pixels may be pixels of the solid state pixel array imager (220). The first set of pixels, which may be a balance of the remaining pixel area, may be an upper region or portion of the solid state light emitting pixel array imager (220), and the second set of pixels may be solid state light emitting pixels. It may be a lower area or part of the array imaging device (220).

  FIGS. 11A-B and 11C-D show non-limiting examples of such multi-image light modulation display elements configured to constitute a predetermined set of individual pixels. Or in a 2d array of pixels on the display element 220, including a plurality of pixel columns, such as pixel columns, each of which directs or directionally modulates the light emitted from each pixel in a predetermined unique direction. Micro optical elements are individually incorporated.

  FIGS. 11A-B and 11C-D show examples in which a multi-image display element is designed to simultaneously modulate an image of each, where each first and second image is emitted in a different direction from the surface of the display element 220. It is configured to be. If such a display element (220) is used within the context of the split exit pupil HUD design architecture of FIG. 2, the first image (described above) will be a far-field distance (eg, far-field distance) ) Produces a first virtual image that can be viewed at about 2.5 m from the HUD system eye box (250). For example, a second virtual image that can be seen at about 0.5 m) is generated. These two viewable virtual images are simultaneously modulated by the multi-image split exit pupil HUD system and the HUD system. The viewer can selectively view either the first or the second virtual image by turning the line of sight in the plane of the vertical axis by an angle. It is proportional to the angle inclination (or separation) of the modulation direction of two virtual images modulated by the plurality of display elements (220) of the split exit pupil HUD system.

11A and 11B are a top view and a side view of a display element (220) according to an embodiment of the present invention, in which a plurality of display elements (220) of a split exit pupil HUD system display first and second images. By comparing the odd and even rows of display pixels, which are configured to modulate by dividing their optical apertures into two display pixel groups. Generate a pixel group. The odd-numbered rows of pixels modulate the first image, and the second group of pixels modulates the even-numbered rows of pixels. Modulate the second image. The directional modulation capability of such a HUD type display element (220) is associated with each image modulation pixel group which can be realized by designing a micro optical element or tft, and the relation between them in a predetermined image direction. A microlens element that modulates the light emitted from the pixel to be emitted in a directional manner. For example, in the case shown in FIGS. 11A and 11B, the micro-optical element associated with the odd row of pixels directly converts the light emitted from the associated pixel group to form one t. The step of generating one image and the micro-optical elements associated with the even-numbered pixel rows direct light emitted from the pixels of the group to form a second image. Note that the rays are shown as being parallel to each image in the figure. FIGS. 11A-11D may actually be used to enlarge or enlarge the image size as needed. , Generally fan out from the imaging device. As will be described in more detail below, the use of non-telecentric micro-optical lens elements in the form of non-telecentric QPI® imagers can enable pixel emission angles.

  In utilizing the single image split exit pupil HUD design architecture described above, note that multiple imagers each modulate the same image in different directions, the collective eye box of the split exit pupil HUD system. Each modulated two virtual images, which provide both virtual images to reside at (250), can be viewed over the collective eyebox (250) but in different vertical (or azimuthal) directions. Can see

The multiple display elements (220) of the split exit pupil multi-image HUD system, which is a preferred embodiment of the further multi-image HUD system shown in FIGS. 11C and 11D, are each divided into two regions or regions of pixels. That is, in the illustrated example, an upper region of the pixel and a lower region of the pixel are formed. In this embodiment, the two images modulated in different directions are each modulated by a single dedicated pixel area. For example, as shown in the figures and figures, the light emitted from each of the display element 220 optical aperture upper regions (which may be any user-defined portion of the imaging pixel set) pixels It has a micro-optical element designed to guide the pixels that make up the upper region, and is configured to form a first image as described above. The display element (220) directs light emitted from each of the pixels forming the lower region of the pixel from the pixels forming the lower region of the pixel so as to form the second image as described above. It has a micro-optical element designed in. Non-telecentric, as described in more detail below. Non-telecentric in the form of an imager. Pixel by using micro optics. Emissions. Angle can be provided.

  FIG. 12 shows a preferred embodiment of the multi-image split exit pupil HUD system of the present invention. As shown in FIG. 12, the plurality of display elements (imagers) (220) can modulate two virtual images, respectively, and the first image has the second image modulated downward. In the meantime, it is modulated upward.

  After the plurality of display elements are collimated by the concave mirror and reflected by the windshield to the eye box, as shown in FIG. 8, the first is to angularly fill the multi-image split exit pupil HUD system eye box. And a plurality of display elements (220) for generating (generating) a collimated light beam comprising two first and second images modulated simultaneously of both the second image and the second image. The multi-image split exit pupil HUD system viewer, which can be seen at two different tilt angles, sees the first virtual image, which can be seen in the far field (260-1), and the near field (260-2) Can focus on two independently simultaneously modulated virtual images with a second virtual image and the two virtual images can be Angle (220-3), which is proportional to the direction separation angle (220￣4), between two images modulated by the plurality of display elements (220). It is proportional to the direction separation angle (220-4).

  The two virtual images are at different first and second virtual distances. This is because those rays are collimated at different levels (different ranges). The concave mirror (230) is designed to achieve a far-field virtual image distance from the eye box (250). Designed to introduce additional collimation of light emitted from each pixel associated with the non-telecentric QPI (r) element associated with the non-telecentric QPI (R) imager described below as a specific example of a specific embodiment. Have been. Thus, the combined collimation achieved by the non-telecentric micro-optics in cooperation with the concave mirror achieves the far-field and near-field virtual image distances from the eyebox, and the far-field and near-field Enables a multi-image HUD that displays both virtual images simultaneously.

  As shown in FIG. 13, the observer of the multi-image split exit pupil HUD system (or can see in focus) has two first or second virtual modulated by the HUD system. Either one of the images can simply redirect its line of sight vertically (azimuthally), causing either one of the two first or second virtual images modulated by the HUD system to have an angle 220 degrees in the direction. -3 (see FIG. 12). Each of the first and second images displayed to the viewer (the two virtual images are independently modulated and separately modulated by two separate groups of pixels making up a display element (imager)) May include different information that may be of interest to the viewer

  FIG. 13 also shows the nominal positions of the virtual first and second images modulated by the multi-image split exit pupil HUD system, wherein the far-field virtual image is a non-limiting illustrated example (vehicle Near-field virtual image can be observed at a distance of about 0.5 m (outer lower edge of the windshield of the vehicle) at a distance of about 2.5 m (approximately at the end of the front hood). Focusing by a person.

  Note that the described HUD multi-image function cannot provide an increase in the volume of the multi-image split exit pupil HUD system outlined in FIG. The display element '(imager) (220), control functions, and uniformity loop also remain unchanged as shown.

The main differences in the implementation and design method of the multi-image split exit pupil HUD system are as follows compared with the described single image split exit pupil HUD system:
1. The plurality of display elements (imagers) (220) have a function of modulating a plurality of images in different directions as described in the previous embodiment,
2. To enable simultaneous modulation of two angularly separated images, the multi-image splitting exit pupil HUD system is angle-divided into directional regions of
3. The image input (715) is a corresponding group of pixels as described in the previous embodiment, consisting of two images (digitally) addressed to a plurality of display images (imagers) (220).

  FIG. 14 shows a selected pixel light output showing an exemplary instantiation of the non-telecentric QP imager referred to above, where the non-telecentric micro-optics can be implemented as a refractive optical element (ROE). 220 is configured to output directly at an approximately oblique angle to the surface to provide a near-field virtual image.

  In this embodiment of FIG. 14, the pixel-level refractive non-telecentric micro-optical element and the directional modulation aspect of 1250-1 are dielectric materials with different refractive indices (1310), which can be realized using t, (1320) including non-centered microlenses (1250-1) formed by successive layers. FIG. 14 is a schematic cross-sectional view of a display element (220) including a plurality of non-telecentric refractive micro-optical elements (1250-1). In this embodiment, an array of pixel-level non-telecentric micro-optical elements can be fabricated monolithically at the wafer level as multiple layers of semiconductor dielectric material, with silicon oxide and high refractive index for the low index layer (1310). Using silicon nitride, semiconductor lithography, etching and deposition techniques for the rate layer (1320). As shown in FIG. 14, a micro-optical element (1250-1) at the array pixel level is realized using a plurality of layers, and dielectric materials (1310) and (1320) have different refractive indices (sequential). The entire microlens array, as needed to obtain the desired non-telecentric characteristics and image projection direction, forming the refractive surface of the pixel-level micro-optical element (1250-1) including body materials (1310) and (1320) Over time, the central position of the refractive microlens element is progressively changed.

  FIG. 15 shows an alternative exemplary example of the non-telecentric QPI® imager described above, wherein the non-telecentric micro-optics has the desired non-telecentric properties and tilted refractive optics (implemented as a ROE). Imaging a selected pixel light output to provide a near field or a second image, characterized by a gradual change across the microlens array as needed to obtain an image projection direction. Can be used to select directly at an approximately oblique angle to the surface of the vessel 220. In this embodiment, a continuous layer of dielectric materials (1410), (1420) having different refractive indices realized using the directional modulation aspect of the pixel-level refractive non-telecentric micro-optical element (1250-2). Includes the formed tilt microlens (1250-2).

  FIG. 15 is a side view of a display element including a plurality of tilted refraction micro-optical elements according to the present embodiment. An array of pixel-level non-telecentric micro-optical elements (1250) has a wafer level as a plurality of layers of semiconductor dielectric material. Silicon oxides such as silicon oxide for the low refractive index layer (1410) and silicon nitride for the high refractive index layer (1420) can be manufactured monolithically with semiconductor lithography, etching and deposition techniques. It is formed by using. As shown in FIG. 15, an array of pixel-level non-telecentric micro-optics can be implemented using multiple layers of dielectric material and 1420. Different refractive indices are deposited successively (continuously) to form the refractive surface of a pixel-level non-telecentric micro-optical element

  Thus, the present invention has several aspects, which may be implemented alone or in various combinations or sub-combinations, as desired. Certain preferred embodiments of the present invention have been disclosed and described herein by way of explanation, but not by way of limitation. It will be understood by those skilled in the art that various changes in form and detail can be made without departing from the spirit and scope of the invention.

  The present invention relates generally to a heads-up display (HUD), and more particularly, to a HUD system that generates one or more virtual images.

  A head-up display is a visual aid that contributes to vehicle safety by allowing a driver of the vehicle to more visually recognize and notify the dashboard information of the vehicle without distracting the driver's view and attention from the road. It is required as an assistive technology. However, currently available head-up displays are bulky and too expensive to be a viable option for use in most vehicles. These same obstacles also occur, albeit to a lesser extent, in applications for aircraft and helicopter head-up displays. For automotive applications of head-up displays, volume and cost constraints are further exacerbated by varying vehicle size, type and cost requirements. Accordingly, there is a need for a low cost, low bulk head-up display suitable for use in small vehicles such as automobiles, small aircraft, and helicopters.

  Prior art HUD systems can be generally categorized into two types: pupil imaging HUDs and non-pupil imaging HUDs. The pupil imaging HUD typically includes a relay module that is responsible for the distribution of intermediate images and pupil formation, image collimation and viewer eye position (here, an "eye-box"). And a collimation module that is responsible for imaging the pupil. The collimation module of the pupil imaging HUD is typically implemented as an inclined curved or planar reflector, or a holographic optical element (HOE), and the relay module is typically used to bend the optical path and reduce optical aberrations. Inclined to compensate. Non-pupil imaging HUD defines the aperture of the system by the light cone angle at the display or at the location of the intermediate image due to diffusion. Also for the intermediate image HUD system, a relay module is required, but the HUD aperture is determined only by the collimation optics. Collimation optics typically have axial symmetry, but are equipped with folding mirrors to meet the required constraints on volume. This is determined by the need for aberration correction and the volume aspects of the system.

  The prior art described in Patent Document 8 and illustrated in FIG. 1-1 minimizes the collimation optics by using a concave HOE reflector (11 in FIG. 1-1) as a combiner and a collimator, and reduces the HUD system. The aspect related to the volume. The resulting HUD system requires complex tilt relay optics (10 in FIG. 1-1) to compensate for aberrations and deliver intermediate images. Further, this HUD system operates only in a narrow spectrum.

  The prior art described in Patent Document 9 and illustrated in FIG. 1-2 uses a relay optics (REL) module and uses a convergent combiner (CMB) mirror (CMB in FIG. 1-2). B) deliver an intermediate image to the focal plane and define the pupil of the system. The CMB mirror collimates the intermediate image and images the pupil of the system to the viewer's eye to facilitate viewing. This pupil imaging HUD approach entails complex REL modules for packaging and aberration correction.

  The prior art, described in US Pat. No. 6,037,045 and illustrated in FIGS. 1-3, uses a projection lens (3) as an image source for projecting onto a diffusing surface (51 in FIGS. A transparent collimating mirror (7 in FIGS. 1-3) is used. The collimating mirror forms an image at infinity, and the aperture of the collimating optics is defined by the angular width of the diffuser.

  The prior art described in Patent Literature 11 and illustrated in FIGS. 1 to 4 employs an image forming source including two liquid crystal display (LCD) panels (23 in FIGS. 1-4) to perform collimation. An intermediate image is formed on a diffusion screen (5 in FIGS. 1-4) arranged at the focal plane of the optical system module (1 in FIGS. 1-4). The main purpose of the two LCD panels of the imaging source is to achieve sufficient brightness for the visibility of the formed image. To this end, the two LCD panels of the imaging source are configured to form, or overlap, two consecutive side-by-side images on the diffuser screen, and halve the horizontal and vertical directions on the diffuser screen. It is configured to form two images that are shifted by pixels.

  The prior art described in U.S. Pat. No. 6,037,056 uses a pair of reflective holographic optical elements (HOEs) to achieve holographic dispersion correction and to place a virtual image of a broadband display source within the observer's field of view. Project. The prior art described in U.S. Pat. No. 6,037,064 also projects an image onto a vehicle windshield using a pair of holographic optical elements (HOE), one transmissive and the other reflective.

  The prior art described in U.S. Pat. No. 6,047,045 and illustrated in FIGS. 1-5, discloses a vehicle that is configured to project an image onto a vehicle dashboard (18 in FIGS. 1-5) with a faceted reflective surface. An image projector (14 in FIGS. 1-5) is used located above the windshield, wherein the faceted reflective surface is configured to reflect the image from the image projector to the vehicle windshield. The surface of the vehicle windshield is oriented to reflect images from each of the dashboard facet surfaces toward the viewer.

U.S. Patent No. 7,623,560, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabrication Thereof, Nov. 24, 2009. U.S. Patent No. 7,767,479, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabrication Thereof. U.S. Patent No. 7,829,902, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabrication Thereof. U.S. Patent No. 8,049,231, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabrication Thereof. U.S. Patent No. 8,098,265, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabrication Thereof. U.S. Patent Publication No. 2010/0066921, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabric Thereof. U.S. Patent Publication 2012/0033113, El-Gouroury et al, Quantum Photonic Imager and Methods of Fabrication Thereof. U.S. Pat. No. 4,218,111, Withrington et al, Holographic Heads-up Displays, August. 19, 1980 U.S. Patent No. 6,813,086, Bignoles et al, Head Up Display Adaptable to Given Type of Equipment, Nov. 2, 2004 U.S. Patent No. 7,391,574, Fredriksson, Heads-up Displays, June 24, 2008. U.S. Patent No. 7,982,959, Lvovskiy et al, Heads-up Displays, Jul. 19, 2011 U.S. Pat. No. 4,613,200, Hartman, Heads-Up Display System with Holographic Dispersion Correcting, Sep. 23, 1986 U.S. Patent No. 5,729,366, Yang, Heads-Up Display for Vehicle Using Holographic Optical Elements, Mar. 17, 1998 U.S. Patent No. 8,553,334, Lambert et al, Heads-Up Display System Utilizing Controlled Reflection from Dashboard Surface Surface, Oct. 8, 2013 U.S. Pat. No. 8,629,903, Seder et al, Enhanced Vision System Full-Windshield HUD, Jan. 14, 2014

B. H. Walker, Optical Design of Visual System, Tutorial tests in optical engineering, published by The International Society of Optical Engineering. 139-150, ISBN 0-8194-3886-3, 2000 C. Guillaux et al, Varilux S Series Breaking the Limits M. Born, Principles of Optics, 7th Edition, Cambridge University Press 1999, Section 5.3, pp. 236-244

  Common to the briefly described prior art HUD system, and several other HUD systems described in the cited prior art, are the high cost and large volume size of the system. Further, none of the prior art HUD systems can be scaled in size and cost to accommodate various automobile and other vehicle sizes and price points. Accordingly, it is an object of the present invention to provide a method for a head-up display that uses a plurality of emissive microscale pixel array imagers to achieve a HUD system that is significantly smaller in volume than a HUD system using a single imaging source. Is to introduce. It is a further object of the present invention to provide a modular HUD system having a volume and cost aspect that can be scaled to accommodate various automobile and light vehicle sizes and price points. The purpose of the present invention is to introduce a method of designing a novel split exit pupil HUD system using a micro-scale pixel array imager. Further objects and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of the invention, which proceeds with reference to the accompanying drawings.

  In the following description, the same reference numerals are used for similar elements in different drawings. The matters defined in this description, such as the detailed structures and design elements, are provided to aid a comprehensive understanding of the exemplary embodiments. However, the invention can be practiced without these specifically defined things. In other instances, well-known functions or constructions are not described in detail as these would obscure the present invention with unnecessary detail. To understand the present invention and to see how it can be carried out in practice, some embodiments of the present invention will be described, by way of example only, with reference to the accompanying drawings, in which: This will be described below.

FIG. 1-1 illustrates a prior art head-up display (HUD) system that uses a concave HOE reflector as a combiner and collimator to minimize collimation optics and reduce the volumetric aspects of the HUD system. FIG. 1-2 illustrates a prior art head-up display (HUD) system that uses a relay optics (REL) module to deliver an intermediate image to the focal plane of a converging combiner (CMB) mirror and define the pupil of the system. Is shown. FIGS. 1-3 show a prior art head-up display (HUD) system using a projection lens (3) as an image source for projecting onto a diffusing surface and using a translucent collimating mirror. FIGS. 1-4 are prior art head-up displays that use an imaging source consisting of two liquid crystal display (LCD) panels to form an intermediate image on a diffusing screen located at the focal plane of a collimation optics module. 1 shows a (HUD) system. FIGS. 1-5 use an image projector mounted above a windshield of a vehicle configured to project an image onto a dashboard of the vehicle having a faceted reflective surface, wherein the faceted reflective surface comprises: 1 illustrates a prior art head-up display (HUD) system configured to reflect an image from an image projector to a vehicle windshield. FIG. 2 illustrates an exemplary modular HUD (MHUD) system of the present invention. FIG. 3 shows the relationship between design parameters and constraints for the MHUD system of FIG. FIG. 4 shows an optical design and a ray trace diagram of a HUD module comprising the MHUD assembly of the embodiment of FIG. FIG. 5 shows the optical performance of a HUD module comprising the MHUD assembly of the embodiment of FIG. FIG. 6 shows a multi-view perspective view of an example MHUD assembly design of the MHUD system of the embodiment of FIG. FIG. 7 is a functional block diagram of an interface and control electronic component design element (substrate) of the MHUD system of the embodiment of FIG. FIG. 8 illustrates a new split eyebox design method for the MHUD system 200 of the embodiment of FIG. FIG. 9 shows the actual volume of the example MHUD assembly design shown in FIG. 6 installed on the dashboard of a subminiature vehicle. FIG. 10 shows the ray paths of the MHUD system of the present invention, including the solar load. 11A and 11B show front and side views, respectively, of a solid state emissive pixel array imager (ie, display element) of an embodiment of the multi-image HUD system of the present invention, wherein the odd rows of pixels are generally Has an output that will produce a first image that is projected outwardly from the surface of the second image, and an even number of rows of pixels are generally projected to some extent below the first image. Indicates that it has an output that will produce an image. 11C and 11D show front and side views, respectively, of a solid state emissive pixel array imager (ie, a display element) of an embodiment of the multi-image HUD system of the present invention. The pixels in the upper region have an output that will produce the second image described above, and the pixels in the lower region of the solid state emissive pixel array imager will produce the first image described above. Indicates that it has an output. FIG. 12 illustrates multiple ray paths for an embodiment of the multi-image HUD system of the present invention. FIG. 13 shows the nominal positions of the near-field virtual image and the far-field virtual image in the low volume package design of the embodiment of the multi-image HUD system of the present invention installed on the dashboard of a subminiature vehicle. FIG. 14 shows a side view of a display element of the present invention comprising a plurality of non-telecentric refractive micro-optics. FIG. 15 shows a side view of a display element of the invention comprising a plurality of tilted refractive micro-optical elements.

  References to “one embodiment” or “an embodiment” in the following detailed description of the invention refer to certain features, structures, or structures described in connection with that embodiment. A feature is meant to be included in at least one embodiment of the present invention. The appearances of the phrase "in one embodiment" in various places in the detailed description are not necessarily all referring to the same embodiment.

Recently, a new class of emissive microscale pixel array imager devices has been introduced. These devices have high brightness, very fast polychromatic light intensity, and spatial modulation capabilities in a very small device size that includes all the necessary image processing drive circuits. The solid state light (SSL) emitting pixels of one such device may be light emitting diodes (LEDs) or laser diodes (LDs), whose on / off state depends on the light emission of the imager. It is controlled by a drive circuit contained in a CMOS chip (or device) to which the microscale pixel array is coupled. The size of the pixels that make up the emissive array of such an imager device is typically in the range of approximately 5 to 20 micrometers, and the typical emissive surface area of the device is approximately 15 to 150 square millimeters . Pixels in a luminescent microscale pixel array device are typically individually addressable in space, color, and time by the drive circuitry of the CMOS chip. The brightness of the light generated by such an imager device can reach millions of cd / m ² at significantly lower power consumption. One example of such a device is the QPI® imager referred to in the exemplary embodiments described below. However, it should be understood that a QPI® imager is merely one example of a type of device that can be used with the present invention. (“QPI” is a registered trademark of Ostend Technologies, Inc.) Thus, in the following description, any reference to a QPI® imager will refer to any available solid state emissive pixel array imager (hereafter referred to as “QPI®”). It is to be understood that the present invention is for the purpose of identifying embodiments disclosed as merely one specific example of an "imager" and is not intended to limit the invention in any way.

  The present invention combines the inherent capabilities of an imager's emissive micropixel array device, as described above, with a novel split exit pupil HUD system architecture to facilitate cost and volume constrained applications such as automotive HUDs. A low-cost, small-volume modular HUD (MHUD) system can be used. The combination of the luminous high-brightness micro-emitter pixel array of an imager such as the QPI® imager and the split exit pupil HUD architecture of the present invention operates effectively even in high-brightness ambient sunlight. The HUD system can be of sufficiently small volume to fit behind dashboards or instrument panels of various vehicle sizes and types. (As used herein, the term "vehicle" is used in its most general sense, including, but not limited to, land, water, underwater, and air travel. The low cost and modularity of the split exit pupil HUD architecture achievable by such an imager allows for a modular HUD that can be adjusted to fit various vehicle volume constraints. The system can be realized. The advantages of the HUD system will become more apparent from the detailed description provided herein in the context of the embodiments described in the following paragraphs.

  FIG. 2 illustrates the design concept of a modular HUD (MHUD) system 200 according to one embodiment of the present invention. As shown in FIG. 2, in this preferred embodiment, the MHUD system 200 of the present invention comprises an MHUD assembly 210 composed of a plurality of modules 215, which are assembled together to form the MHUD assembly 210. Thus, each module 215 is comprised of a single imager and associated optics 220 and concave mirror 230. As shown in FIG. 2, light emitted from each of the single imagers with associated optics 220 is partially collimated, magnified and reflected by the associated concave mirror 230 and then partially to the front of the vehicle. Reflected away from the glass 240 to form a virtual image 260 that is visible within the eyebox segment 255 at the nominal head position of the vehicle driver. As shown in FIG. 2, each module 215 of the MHUD assembly 210 at any one time places the same virtual image 260 at the same location from the vehicle's windshield 240, but in each corresponding eyebox segment 255. The plurality of modules 215 of the MHUD assembly 210 together form a collective eye box 250 of the MHUD system 200. That is, the virtual image 260 is partially visible from each eye box segment 255 and is entirely visible in the collective eye box 250. Accordingly, the overall size of the eyebox segment 255 of the MHUD system 200 can be adjusted by selecting an appropriate number of modules 215 that make up the MHUD assembly 210, and the number of eyebox segments and modules can be user-defined. Things. Although each module 215 of the MHUD assembly 210 is arranged to form the same virtual image 260 at any one time, these images will of course change over time, such as a fuel gauge image. The MHUD system 200 of the present invention allows the image data to be available at a typical video rate, although it may change slowly or quickly as in the display of the displayed images of a GPS navigation system. In some cases, it may operate at frequencies up to at least such a rate.

  In this preferred embodiment of MHUD system 200, each eyebox segment 255 of module 215 of MHUD assembly 210 is located at the exit pupil of the bundle of rays reflected by corresponding concave mirror 230. The collective eyebox 250 of the MHUD system 200 is effectively a single split exit pupil eyebox formed by the overlap of the eyebox segments 255 of the module 215 of the MHUD assembly 210. The method of designing the split exit pupil of the MHUD system 200 of the present invention will be described in more detail in the following paragraphs.

  In this preferred embodiment of the MHUD system 200 of the present invention, the MHUD assembly 210 is comprised of a plurality of modules 215, which are assembled together to form the MHUD assembly 210, whereby each module 215 has a QPI ( An imager such as a registered trademark imager or other suitable light emitting structure such as an OLED device, and associated optics 220 and concave mirror 230. The method of designing the MHUD assembly 210 and its respective modules 215 of the MHUD system 200 of this embodiment of the present invention will be described in more detail in the following paragraphs, but before that, the related advantages of the MHUD system 200 of the present invention and A trade-off between related design parameters will be described.

Optical Design Parameter Trade-Offs of MHUD System 200 To understand the advantages of the MHUD system 200 of the present invention, the underlying design trade-offs of a typical HUD system and the relationships between the related design parameters are described. Is considered important. The virtual image generated by the HUD system is typically superimposed on a natural scene, which allows the viewer to steer the vehicle without having to remove his view and attention from the road or the outside environment of the vehicle. To visually recognize the operating parameters of the vehicle and provide important information such as, for example, navigation information. Important parameters to consider in the design of the HUD system include: target size of the assembled eye box; desired field of view (FOV); size of the virtual image to be formed; resolution of the virtual image; The relationship between these design parameters and constraints is shown in FIG.

How the Modular HUD (MHUD) of the Present Invention Implements Volume Reduction Referring to FIG. 3, reducing the size of the imager 220 of the MHUD system 200 leads to a smaller effective focal length (EFL); This is the characteristic optical track length of the system and generally contributes to a reduction in system volume. However, if the size of the eyebox is maintained, reducing the size of the aperture of the imager leads to a lower system F / #, which is accompanied by an increase in optical complexity. This generally results in a larger system volume. With respect to the design concept of the MHUD system 200 shown in FIG. 2, scaling the size of the eyebox segment 255 for each module 215 with the size of the imager 220 avoids increasing optical complexity. This leads to expansion and contraction of the volume of each module 215 depending on the size ratio of the imager 220. The plurality of modules 215 combine to form an MHUD assembly 210 that can provide an arbitrarily sized aggregate eye box 250. The novel design concept of the segmented eyebox of the MHUD system 200 of the present invention is realized by dividing the exit pupil of the system formed in the viewer's eyebox into segments. Each segment corresponds to one of the eyebox segments 255 that make up the collective eyebox 250 of the MHUD system 200 of the present invention. Thus, such a split exit pupil design method of the MHUD system 200 of the present invention achieves a smaller overall volume aspect compared to prior art HUD systems that provide the same size eyebox. This desirably leads to a reduction in the overall volume, complexity and cost of the HUD. Other advantages of the disclosed split exit pupil design method of the MHUD system 200 of the present invention disclosed herein will be described in the following description. Of course, since each module emits the same image at any one time, the driver of the vehicle will have the same position regardless of which one or more eyebox segments 255 he is viewing. Will see the same virtual image.

  A major contributor to the volume of prior art HUD systems using mirror reflectors (U.S. Patent Nos. 6,059,009 to 6,087,059) has been identified as concave mirrors. In addition to the large size of the mirror itself, the size of the image source also grows proportionately, either by using a large size imager, such as an LCD panel, or by forming a large size intermediate image that is projected onto a diffusing screen. The latter adds a larger volume to incorporate a projector imager and associated projection optics. As explained in the above description, the MHUD system 200 of the present invention is assembled together to form an overall reflector 235 (which is very small in size and achieves a very small optical track length) of the MHUD assembly 210. By using the MHUD assembly 210 composed of a plurality of modules 215 each using a relatively small sized concave mirror 230, a significant improvement over prior art HUD systems using a single concave mirror as the main reflector. A small volume aspect is achieved. The MHUD assembly 210 using the imager 220 having a small aperture allows the use of a concave mirror 230 having a small aperture, and the concave mirror 230 has a small optical track length. Resulting in a MHUD system 200 that is very small and volume efficient.

  The design of the MHUD system 200 of the present invention works by splitting a large collimated beam, typically created by a single large mirror, into three equal sized collimated sub-beams in the exemplary embodiment. . Each sub-beam is generated by the optical subsystem of module 215. As a result, F / #, optical complexity, and focal length (EFL) (or optical track length) are reduced, resulting in a reduction in the physical volume envelope of the system. FIG. 4 shows an optical design and a ray trace diagram of the module 215 constituting the MHUD assembly 210. As shown in FIG. 4, the module 215 of one preferred embodiment comprises one imager and its associated optics 220 and concave mirror 230. In the embodiment shown in FIG. 4, the optical system 420 associated with the imager 410 is shown as a separate lens optic, but in an alternative embodiment of the invention, the optical system 420 associated with the imager is replaced by the imager 410. The integrated imager assembly 220 may be formed by mounting directly on top of the light emitting surface. As shown in FIG. 4, in each module 215, the reflective concave mirror 230 magnifies and collimates the image generated by the corresponding imager (or other imager) 220 to form one eyebox of the collection eyebox 250. The optical element 420 associated with the imager 410 of FIG. 4, which forms the segment 255, balances off-axis distortion and tilt aberration due to the reflective concave mirror 230.

  FIG. 5 shows the optical performance of the module 215 of the MHUD assembly 210. As shown in FIG. 5, the role of the optical element 420 associated with the imager 410 is to balance off-axis distortion and tilt aberration caused by the reflective concave mirror 230, thereby reducing the modulation transfer function (MTF). The goal is to minimize the swimming effect of the image while maintaining it at a sufficiently high level. For completeness, the swimming effect of an image is typically caused by fluctuations in the direction of light entering the viewer's pupil, due to optical distortions caused by mirror aberrations, and this is caused by the viewer's head Moving around (or staring at) the eye box of a HUD system results in perceivable erroneous movement of the virtual image (known as the "swimming effect") (US Pat. No. 6,037,037). In extreme cases, the excessive swimming effects of virtual images can lead to motion sickness-like sensations, dizziness or nausea caused by collisions between the vestibular and eye movement aspects of the human visual and perceptual system. In some cases, it is extremely important to minimize the swimming effect in a binocular optical system such as a HUD, since the connection may be made (Non-Patent Documents 1 and 2).

  Another advantage of the split exit pupil method of the MHUD system 200 of the present invention is that the method described above significantly reduces the swimming effect compared to prior art HUD systems that use a single mirror with a large optical aperture. Is to achieve. The aberration of the small optical aperture of the reflective concave mirror 230 is much smaller than the aberration of a relatively large optical aperture mirror used in conventional single mirror HUD systems. Since the swimming effect is directly proportional to the magnitude of the optical distortion (or beam direction deflection) caused by the aberrations caused by the HUD reflecting mirror, the multiple light concave mirrors 230 of the MHUD system 200 of the present invention have a small optical aperture. Achieves a significantly smaller swimming effect compared to technology HUD systems. In addition, due to the angular overlap between the eyebox segments 255 of the MHUD module 215 (described in more detail in the description of FIG. 8), the perception of any point in the virtual image 260 causes the optical contribution from the plurality of MHUD modules 215 to increase. Incorporated. As a result, optical distortions (or ray direction deflections) caused by aberrations of the individual concave mirrors 230 of the plurality of MHUD modules 215 have a tendency to average out at any point in the virtual image 260, The overall swimming effect perceived by the viewer of the MHUD system 200 is reduced.

  In another embodiment of the present invention, the imager 220 of the MHUD assembly 210 has a higher resolution than is possible with the human visual system (HVS), and this additional resolution is due to the concave mirror 230. It is dedicated to digital image warping pre-compensation for residual optical distortion caused by aberrations. In a typical HUD viewing experience, virtual images are formed at a distance of approximately 2.5 m. The lateral vision of HVS is approximately 200 microradians. At such a distance, the HVS may have a resolution of approximately 2500 × 0.0002 = 0.5 mm pixels, which corresponds to a resolution of approximately 450 × 250 pixels for a virtual image 260 having a 10 inch diagonal. I do. The imager 220 used in the exemplary MHUD assembly 210 can provide a much higher resolution than this limit, eg, 640 × 360 pixels, or even 1280 × 720 pixels, with the same size optical aperture. The imager 220, which provides higher resolution with the same size optical aperture, allows the use of a concave mirror 230 having the same size optical aperture, thus maintaining the volume advantages of the MHUD assembly 200. The additional resolution of the imager 220 allows for the use of digital image warping pre-compensation, but this allows for the maximum achievable resolution in the virtual image 260, and the concave surface, while maintaining the same advantages as described above for volume. Optical distortion due to the aberration of the mirror 230 and the resulting swimming effect are substantially eliminated.

  Each reflective concave mirror 230 may be aspheric or free-form, whereby the aspherical or free-form factor of the concave mirror 230 is dependent on the optical aberrations of the concave mirror 230 and, if necessary, the curvature of the windshield. It is chosen to be minimal. It should be noted that the position of each imager 220 is preferably axially symmetric with respect to the concave mirror 230 associated therewith, thereby optimizing the balance of aberrations at any two adjacent edges of the concave mirror 230 ( To some extent). This is an important aspect of the design of the MHUD system 200 of the present invention because it guarantees a uniform viewing transition of the virtual image 260 between the plurality of eyebox segments 255 of the collective eyebox 250 of the MHUD system 200. is there.

  FIG. 6 shows a multi-view perspective view of the MHUD assembly 210. As shown in FIG. 6, the MHUD assembly 210 is composed of three reflective concave mirrors 230 assembled together in an enclosure 600. The three concave mirrors 230 can be fabricated separately and then assembled together in the enclosure 600, or they can be fabricated as a single part and assembled into the enclosure 600. The three concave mirrors 230, whether assembled separately or as a single optical component, may be fabricated using embossed polycarbonate plastic, and the optical surface may then be fabricated using a sputtering technique. , Coated with a thin layer of a reflective metal such as silver or aluminum. As shown in FIG. 6, the rear side wall of the enclosure is composed of three separate sections 610, each incorporating an optical window 615, which incorporates the rear side wall section 610 and each of the concave mirror 230. Are assembled with the optical axis of each concave mirror 230 when assembled together. As shown in the side perspective view of FIG. 6, the upper edge 617 of each rear sidewall section 610 is angled toward the concave mirror 230, thereby providing the angled edge surface of the rear sidewall section 610. The imager 220 mounted on 617 can be aligned with the optical axis of each concave mirror 230.

  As shown in the rear perspective view of FIG. 6, the rear side wall section 610 is assembled together on one side of the back plate 630, and the control and interface electronics (printed circuit board) 620 of the MHUD assembly 210 is attached to the back plate 630. Installed on the opposite side of In addition, the back plate 630 also incorporates temperature cooling fins to dissipate the heat generated by the imager 220 and interface electronics 620 of the MHUD assembly 210. As shown in the rear perspective view of FIG. 6, each imager 220 is mounted on a flexible electronic board 618 that connects the imager 220 to control and interface electronics 620.

  As shown in the rear perspective view of FIG. 6, a photodetector (PD) 640, typically a photodiode, is centrally located at the boundary edge of each pair of concave mirror 230 and rear sidewall section 610. Each photodetector 640 may be incorporated and positioned and oriented to detect light emitted from imager 220 to each concave mirror 230. Typically, three photodiodes are used in each module, one for each color of emitted light. The output of the photodetector (PD) 640 is connected to the control and interface electronics 620 of the MHUD assembly 210 and is implemented in the hardware and software design elements of the interface electronics 620 (described below). Used as input to the uniformity control loop. Also provided as input to the control and interface electronics 620 of the MHUD assembly 210 is the output of an ambient light detector sensor 660, which is typically an integrated component of the brightness control of the dashboard of most vehicles. .

  The control and interface electronics 620 of the MHUD assembly 210 incorporates the hardware and software design functional elements shown in the block diagram of FIG. 7, which include an MHUD interface function 710, a control function 720, and uniformity. Includes a loop function 730. The MHUD interface function 710 of the control and interface electronics 620 of the MHUD assembly 210 is typically implemented in a combination of hardware and software, and provides an image input 715 from a vehicle driver assistance system (DAS). And incorporating the color and brightness correction 735 provided by the control function 720 into this image, and then providing the image inputs 744, 745, 746 to the imager 220 of the MHUD assembly 210. Although the same image input 715 may be provided to the three imagers 220 of the MHUD assembly 210, the MHUD interface function 710 uses the color and brightness correction 735 received from the control function 720 to determine the color and brightness specific to each imager 220. Brightness correction is incorporated into each image input 744, 745, 746.

  The uniformity loop function 730 of the control and interface electronics 620 includes a photodetector () of each module 215 of the MHUD assembly 210 to ensure color and brightness uniformity over the plurality of segments 255 of the collective eyebox 250. After receiving the input signals 754, 755, 756 from the PD 640 and calculating the color and luminance associated with each module 215 of the MHUD assembly 210, the color and luminance can be made more uniform across the multiple segments 255 of the collective eyebox 250. Calculate the color and brightness corrections needed to do so. This is achieved with the aid of an initial calibration look-up table that is implemented and stored in the memory of the control and interface electronics 620 when the MHUD assembly 210 is first assembled. Next, the color and brightness corrections calculated by the uniformity loop function 730 are provided to the control function 720, which applies these corrections to the input received from the ambient light sensor 650, and to the external color and brightness adjustment input commands. In combination with 725, a color and brightness correction 735 is generated, which is then incorporated into the image data by the MHUD interface function 710, and the corrected image data is then provided to the imager 220 as image inputs 744, 745, 746. Provided. In incorporating the input received from the ambient light sensor 650 into color and brightness correction, the control function 720 may control the virtualization of the heads-up display in proportion to, or in relation to, the brightness of the vehicle's external light. Adjust the brightness of the image. It should be noted that “image data” as used herein may be received as an input to a heads-up display, provided to an imager, or in any other form. Means any type of image information.

  As described above, one embodiment of the MHUD system 200 uses an imager 220 that has a higher resolution than the maximum resolution that the HVS can have in the virtual image 260 and digitally warps the image input to the imager 220. Incorporate means to eliminate or significantly reduce optical distortions and swimming effects caused by. The MHUD interface function 710 of the MHUD assembly 210 of the MHUD system 200 of the embodiment includes a plurality of data each incorporating data identifying digital image warping parameters required to pre-compensate for residual optical distortion of each concave mirror 230. A look-up table may also be incorporated. These parameters are used by the MHUD interface function 710 to warp the digital image input of each imager 220 such that the image data to each imager 220 pre-compensates for the residual distortion of the corresponding concave mirror 230. The digital image warping parameters embedded in the look-up table of the MHUD interface function 710 are generated in advance by the optical design simulation of the MHUD assembly 210, and then the digital image warping pre-compensation after the MHUD interface function 710 applies the digital image warping pre-compensation. Augmented by optical test data based on measurement of residual optical distortion of module 215. The resulting digitally warped data is then combined with the color and luminance correction 735 provided by the control function 720 to provide color and luminance corrected and distortion pre-compensated image data into the MHUD assembly. Provided as image inputs 744, 745, 746 to the imager 220 at 210. With this design method of the MHUD system 200, the residual optical distortion caused by the concave mirror 230 and the resulting swimming effect can be greatly reduced or completely eliminated, and thus the MHUD system 200 without distortion can be realized.

  As shown in the perspective view of FIG. 6, above the MHUD assembly 210 is a glass cover 430, which serves as an optical interface window for the MHUD assembly 210 on the top surface of the vehicle dashboard and is exposed to sunlight by the imager 220. Acts as a filter to attenuate the infrared emission of sunlight to prevent thermal loading. The glass used should be selected to also have significant transmission for the wavelength of light of interest.

  The above design method of the MHUD assembly 210 utilizes features of the human visual system (HVS) to simplify the design implementation and assembly tolerances of the MHUD assembly 210. First, the MHUD assembly 210 has a pupil diameter of approximately 5 mm (3-5 mm during the day and 4-9 mm at night) and the resulting lateral vision when viewing the virtual image 260. An indistinguishably small gap is allowed between the concave mirrors 230, which may be as wide as 1 mm. Second, the eye difference adjustment limit of approximately 0.5 ° allows for a small angular tilt between the concave mirrors 230 of the MHUD assembly 210, which can reach approximately 0.15 °. . This allowance for tilt and gap greatly relaxes the mechanical alignment tolerance requirements for the concave mirror 230 of the MHUD assembly 210, and thus provides a very cost-effective manufacturing and fabrication for the MHUD assembly 210. An assembly approach can be realized. Any additional tilt and / or alignment requirements can usually be easily accommodated by software.

  FIG. 8 shows the novel split eyebox design of the MHUD system 200 of the present invention. The diagram of FIG. 8 is intended to show the relationship between the aggregate eyebox 250 and the virtual image 260 of the MHUD system 200. FIG. 8 also shows an exemplary object 810 (arrows shown on virtual image 260) displayed by MHUD system 200. In the design of the MHUD system 200, each eyebox segment 255 will typically be positioned at the exit pupil of its respective module 215. As a result, the image information presented to the viewer's eyes within each eyebox segment 255 is in that angular space. Thus, the arrow-shaped object 810 of the virtual image 260 that is divided and presented to the viewer within each eyebox segment 255 typically has the viewer's head positioned within the central region of each eyebox segment 255. When the viewer's head is moved to the right or left of the eyebox segment 255, the tip or tail of the arrow-shaped object 810 of the virtual image 260 is gradually increased. It will blur (or fade away). In the design of the MHUD system 200, as shown in the perspective view of FIG. 6, when the module 215 is integrated into the MHUD assembly 210, the eyebox segments 255 of the module 215 are overlapped as shown in FIG. Thereby, the collective eye box 250 of the MHUD system 200 is generated. Thus, the collective eyebox 250 of the MHUD system 200 is formed by the overlap of the exit pupil areas forming the eyebox segments 255 of the plurality of modules 215, and is therefore presented to the viewer's eyes within the collective eyebox 250. The resulting image information results in an angular multiplexed view of the virtual image 260 that extends across the combined angular field of view of the MHUD module 215. As shown in FIG. 8, the arrow-shaped object 810 of the virtual image 260 is completely visible (or viewable) within the overlap area of the eyebox segment 255 that defines the collective eyebox 250 of the MHUD system 200. The arrow-shaped object 810 of the virtual image 260 gradually becomes blurred (or disappears) as the viewer's head moves to the right or left of the peripheral area of the collection eyebox 250, respectively.

The size of the overlap between the eyebox segments 255 of the module 215 depends on their angular blur profile (820 in FIG. 8) and determines the final size of the aggregate eyebox 250 of the MHUD system 200. The latter is defined as the area boundaries or dimensions of the collective eyebox 250 within which the virtual image 260 is fully visible (or viewable) with the desired brightness uniformity. FIG. 8 also shows the shielding of the resulting angular blur profile of the MHUD assembly 210 over the entire area of the overlapping eyebox segment 255 of the module 215. As shown in FIG. 8, the brightness of the virtual image 260 perceived by the viewer includes the brightness contribution components Λ _R , Λ _C , Λ _L (left, center, right) from each module 215. The criterion for defining the boundaries of the aggregate eyebox 250 is that of the eyebox segment 255 in which the brightness of the virtual image 260 is uniform within a given threshold λ (eg, less than 25%) over a selected area. Area of overlap A, ie Var _A (Λ _R + Λ _C + Λ _L ) ≦ λ (desired uniformity threshold). Due to the above criteria defining the boundaries of the collective eyebox 250 shown in FIG. 8 and the overlap of the eyebox segments 255 of the module 215, the perceived brightness over the virtual image 260 will be at least 50 from one of the modules 215. Includes% contributing components. This means that anywhere within the bounds of the aggregate eyebox 250 defined by the above criteria, each module 215 provides at least 50% of the perceived brightness of the virtual image 260. When using this design approach of the MHUD system 200, the desired luminance uniformity of the virtual image 260 is a criterion that defines the size of the aggregate eye box 250. This design criterion is illustrated in the design example of FIG. 8 using a uniformity threshold λ = 25% to form a collective eye box 250 having a width of 120 mm. As shown in FIG. 8, using a uniformity threshold λ = 37.5% defines an aggregate eyebox 250 that is approximately 25% wide, measuring approximately 150 mm.

  As shown in FIG. 8, in the area of the eyebox segment extending beyond the right and left sides of the collective eyebox 250 of the MHUD system 200, the arrow-shaped object 810 of the virtual image indicates that the viewer's head is As you move into the area, it gradually fades or disappears. Using the above design approach of the MHUD system 200, the addition of a module 215 to the right or left side of the MHUD assembly 210 shown in FIG. 6 allows the collection eye box 250 of the MHUD system 200 to be defined by the design criteria defined above. The lateral width is extended to the right or left, respectively, so that the arrow-shaped object 810 of the virtual image 260 is completely visible with the desired brightness uniformity. If another row of modules 215 is added to the MHUD assembly 210, a similar effect of extending the height of the collective eyebox 250 occurs in the orthogonal direction. Thus, using such a modular design method of the MHUD system 200 of the present invention, by adding additional modules 215 to the MHUD assembly 210, having any width and height dimensions selected by design Can be realized.

  In essence, the split exit pupil modular design method of the MHUD system 200 of the present invention allows the use of multiple imagers 220 and concave mirrors 230, each having a relatively small aperture and each having a short optical track. Achieving the length replaces the very long optical track length of a long image source and the single mirror used in prior art HUD systems. Thus, combining the small aperture imager 220 and concave mirror 230 of the MHUD module 215 achieves a prior art HUD system that uses a larger single image source and a single mirror to obtain the same size eyebox. Volumetric aspects can be realized that are significantly smaller than can be achieved. Further, the size of the collective eyebox 250 of the MHUD system 200 achieved can be adjusted by using an appropriate number of modules 215 (basic design elements). Conversely, the volume aspect of the MHUD system 200 is larger than what can be achieved with prior art HUD systems that can fit the same available volume while matching the volume available in the dashboard area of the vehicle. Can be achieved.

  To illustrate the above advantages with respect to the volume of the MHUD system 200 of the present invention, the perspective view of FIG. 6 shows three imagers 220 with an optical aperture size of 6.4 × 3.6 mm each and an optical aperture size of 60 mm each. FIG. 4 shows the design dimensions of the MHUD assembly 210 using three concave mirrors of 100 mm to achieve a size of the aggregate eye box 250 of 120 × 60 mm based on the brightness uniformity threshold λ = 25%. Based on the design dimensions shown in FIG. 6, the total volume of MHUD assembly 210 is approximately 1350 cc (1.35 liters). For comparison purposes, the total volume of a prior art HUD system using a single mirror with a larger aperture and a single larger image source to achieve the same eyebox size is 5000 cc ( 5 liters). Therefore, the above-described design method of the MHUD system 200 of the present invention can realize a HUD system having 3.7 times higher volumetric efficiency (that is, 3.7 times smaller) than the prior art HUD system. To visualize this advantage in terms of volume, FIG. 9 shows the volume of the example design of the MHUD assembly 210 shown in FIG. 6 installed on the dashboard of a subminiature vehicle. As shown in FIG. 9, the volume efficient design of the MHUD system 200 of the present invention adds the functionality of the HUD to a very limited dashboard volume that cannot be easily fitted to prior art HUD systems. it can.

  FIG. 10 shows the ray paths of the MHUD system 200. As shown in FIG. 10 and as already described and illustrated in FIG. 2, each of the three imagers 220 constituting the MHUD assembly 210 has the same image of the same resolution (for example, 640 × 360 pixels). After each reflection by three concave mirrors 230, the entire 120 × 60 mm collective eyebox 250 of the above design example is angularly addressed to span the 125 × 225 mm virtual image 260 of the above design example. , 640 × 360 pixels.

  FIG. 10 shows design requirements for generating a luminance of 10,000 cd / m 2 in the virtual image 260. With a typical windshield reflectivity of approximately 20%, and the criteria for defining the boundaries of the collective eyebox 250 described above, each of the three imagers 220 will produce a luminance of approximately 25,000 cd / m2. To conservatively estimate, the three imagers 220 of the MHUD assembly 210 and the control and interface electronics 620 consume approximately 2W in total to produce 25,000 cd / m2 of brightness, which That is approximately 25% of the power consumption of the prior art HUD system.

  Referring to the performance of the MHUD system 200 shown in FIG. 5, the enclosed energy plot of FIG. 5 shows the geometry of the collimated light beam from the optical aperture (size 180 micrometers) of the concave mirror 230. Indicates the target blur radius. Using the design example of each module 215 shown in FIG. 6 with an effective focal length of 72 mm, the blur size at 180 micrometers shown in the enclosed energy plot of FIG. For a light beam emitted from one pixel at 220 and collimated by a corresponding concave mirror 230, it gives an angular spread of 0.143 °. The swimming effect relates to an angular spread of 0.143 ° from one pixel to the entire beam width, while the resolution (MTF) is determined by the effective beam width sampled by the size of the pupil of the eye. The MTF plot of FIG. 5 shows the MTF of each module 215 calculated for a typical eye pupil aperture of 4 mm in diameter. The smaller the angle of the angular spread, the smaller the swimming radius in the virtual image 260. For a virtual image 260 viewed 2.5 m from the collective eyebox 250 of the MHUD system 200, the corresponding swimming radius for the MHUD system 200 design example would be 6.2 mm. A prior art HUD system that uses a single mirror and has an optical aperture size equal to the overall aperture size of the example design of the MHUD assembly 210 provides an optical aperture that is approximately 2.4 times larger than the optical aperture of the module 215. Have. Since the aberration blur size is directly proportional to the cube of the aperture size (Non-Patent Document 3), the prior art single-mirror HUD system having an optical aperture size equal to the size of the entire aperture in the MHUD assembly 210 design example has a If the second order accidentally compensated for a large third order aberration (which is intentionally not achievable by design), then it has a corresponding swimming radius of approximately 14.3 mm; Single mirror HUD systems typically have a corresponding swimming radius of approximately 39.7 mm, which is 6.2 times larger than the swimming radius achieved by the MHUD system 200 design example. Also, using the above-described aberration pre-compensation method, the swimming radius of the MHUD system 200 can be significantly reduced, or even completely eliminated, than specified for this design example.

  FIG. 10 also shows the ray path of the MHUD system 200, including the sunlight load. As shown in FIG. 10, the reverse light path of sunlight impinging on the windshield of the vehicle reaches the area of the collection eyebox 250, possibly causing glare in the virtual image 260. In the design of the MHUD system 200 of the present invention, the amount of sunlight that can reach the collective eyebox 250 is significantly smaller than in a conventional HUD system. First, assuming that the light transmittance of the windshield 240 is 80%, light rays from the sun are attenuated by the windshield 240 to a maximum of 80% of its brightness. Second, the sun rays transmitted through the windshield 240 and reflected by one of the concave mirrors 230 toward the corresponding imager 220 are anti-reflective (AR) of the optical aperture of the imager 220. The coating attenuates up to 5% of its brightness and is then reflected back toward the concave mirror 230 assembly. Third, sunlight in this reverse path is attenuated to a maximum of 20% of its brightness as it is reflected by windshield 240 toward collective eye box 250. As described above, the image glare 220 and concave mirror 230 of each module 215 contribute up to 50% to the brightness of the virtual image 260, so that sunlight glare reflected from the module 215 exposed to sunlight will It will appear to have been further attenuated by 50%.

  Thus, based on this path attenuation analysis, sunlight arriving at the collection eye box 250 is attenuated to a maximum of 0.4% (much less than 1%) of its brightness. The ability of the MHUD system 200 to generate 10,000 cd / m2 brightness and 0.4% daylight glare in the virtual image 260 allows the MHUD system 200 to tolerate daylight brightness in excess of 250,000 cd / m2, Equivalent to a unified glare rating (UGR) (or glare-to-image intensity ratio) of approximately 28 dB. It should be noted that while the glass cover 430 is infrared-absorbing, it is transparent to light of the wavelengths used in the head-up display of the present invention, so that heat from sunlight loading can be reduced. The concave mirror 230 assembly prevents concentration back into the imager 220.

  In the embodiments described above, a plurality of modules are arranged side by side to provide overlapping eyebox segments, thereby providing a collective eyebox 250 that is wider than the eyebox segment 255 itself. However, if desired, instead of or in addition to the above, the modules may be arranged such that the eyebox segments of module 215 are stacked to provide a higher collective eyebox 250. Again, again, all modules display the same virtual image at the same location in front of the vehicle. It should be noted that the lamination to provide the higher collective eyebox 250 is generally not a module lamination, but because of the typical windshield slope, the lamination of the eyebox segments is merely for additional modules. May be achieved by using a large, generally horizontal area of the dashboard.

  Also, as shown in FIG. 2, the light emitted from each of the single imagers with associated optics 220 is partially collimated, magnified, and reflected by the associated concave mirror 230 before being partially reflected. Reflected away from the vehicle windshield 240 to form a virtual image 260 that is visible within the eyebox segment 255 at the nominal head position of the vehicle driver. " However, in any of the embodiments, the degree of collimation achieved by the concave mirror is not always perfect and is intended to limit how far in front of the vehicle the virtual image will be formed. May be set to In some cases, by designing the concave mirror indeed to intentionally distort the collimation, this is the most prominent example of any subsequent source of aberration (if windshield curvature is present). ) May be offset.

  It has already been shown that off-axis distortion and tilt aberration, as well as color and brightness correction, can be implemented in the control and interface electronics 620 of the MHUD assembly 210 of FIG. Of course, the lateral position correction of each image or image segment from each module 215 may also be performed (or mechanically) in the control and interface electronics 620, thereby providing a double image or double image. The image part disappears. Further, it should be noted that "brightness correction" has at least two main aspects. The first and most prominent aspect is the correction of variations in brightness between modules, so that the brightness (and color) of images from different modules will not be different. Associated with this, however, is the fact that image warping and other factors can potentially cause variations in the brightness of multiple image portions within an individual module, where the change in pixel spacing due to warping is significant. Can cause visible brightness aberrations. When this occurs, the brightness of the individual pixels in each module can be individually controlled, so if necessary, locally increase the brightness of the pixels in areas where pixel separation increases, and In the decreasing area, the brightness of the pixel can be reduced locally. Finally, it is noted that typical solid-state emissive pixel array imagers are not square imagers, but are typically unequal-sized rectangles. Consequently, the choice of imager orientation can also provide additional variables that can be utilized in the design of the head-up display of the present invention.

  Table 1 below shows the salient performance characteristics of an imager-based MHUD system 200 for a particular embodiment of the present invention, which uses a single larger mirror and a single larger image source. 3 illustrates the performance advantages of certain embodiments of the present invention over prior art HUD systems. As shown in Table 1, the split exit pupil MHUD system of the present invention is many times better than the conventional HUD system in all performance categories. Further, due to reduced manufacturing tolerances and smaller mirror sizes, as described above, the MHUD system 200 of the present invention is much more cost-effective than prior art with comparable eyebox sizes. Expected to be higher.

Multi-image head-up display system using near-field and far-field virtual images In a number of HUD system applications, the HUD system allows the viewer to view multiple virtual images, preferably additional information, securely for the viewer. It is desirable to display in front of the viewer so as to provide the possibility but not divert the viewer's attention from driving. In this context, a plurality of virtual images may be displayed by the HUD system, for example, wherein a first virtual image is displayed at a far-field distance typically employed by conventional HUD systems, and a second virtual image is displayed at a second distance. Is displayed at a near-field distance. Preferably, both these virtual images are viewable for the viewer of the HUD system without having to keep his head away from the road and so that he can keep his attention on driving conditions.

  In certain preferred alternative embodiments of the disclosed invention, the split exit pupil design architecture described above may be used with a plurality of display elements 220 (ie, an imager and associated optics 220), as shown in FIG. , Each display element 220 is configured to modulate a plurality of images at different output angles.

  In one aspect of the multi-image head-up display system of the present invention, the system may include a plurality of modules 215, each module 215: a solid state emissive pixel array imager (ie, display element) 220; First and second virtual images viewable in the eyebox segment by collimating, magnifying, and reflecting toward the windshield of the vehicle, the first and second images generated by the neutral pixel array imager 220. A concave mirror 230 configured to form an image. The plurality of modules combine the eyebox segments 255 so that the heads-up display is provided as having a larger aggregate eyebox 250 than the eyebox segments 255 of each module 215, and the multiple eyebox 250 Is located at the nominal head position of the driver. In this first aspect of the multi-image head-up display system of the present invention, the solid state emissive pixel array imager 220 includes a first set of pixels associated with each of a first set of micro-optics, and a second set of pixels. A second set of pixels associated with each set of micro-optical elements. The first set of micro-optics is configured to orient the output from each of the first set of pixels to produce the first image described above, thereby providing a first distance from the collective eye box 250. A first virtual image that can be viewed at is generated. The second set of micro optics is configured to direct the output from each of the second set of pixels to produce the second image described above, thereby providing a second distance from the collective eye box 250 A second virtual image that can be viewed at is generated. The micro optics may include a non-telecentric lens or non-telecentric optics configured to provide a pixel output that is totally inclined with respect to the surface of the solid state emissive pixel array imager 220.

  In the first aspect of the embodiment of the multi-image head-up display system of the present invention, the first distance may be a far-field distance, and the second distance may be a near-field distance. . The first set of pixels may be a user-defined first set of pixels of the solid state emissive pixel array imager 220, and the second set of pixels may be a solid state emissive pixel array imager 220. , A second set of pixels of a user-defined type. The first set of pixels may be odd rows of pixels of the solid state emissive pixel array imager 220, and the second set of pixels may be even rows of pixels of the solid state emissive pixel array imager 220. Good. The first set of pixels may be the even rows of pixels of the solid state emissive pixel array imager 22, and the second set of pixels may be the odd rows of the solid state emissive pixel array imager 220. Good. The first set of pixels may be pixels that make up at least 50% of the pixel area of the solid state emissive pixel array imager 22, and the second set of pixels may be those of the solid state emissive pixel array imager 220. It may be the remainder of the pixel area. The first set of pixels may be an upper region or upper portion of the solid state emissive pixel array imager 220, and the second set of pixels may be a lower region or lower portion of the solid state emissive pixel array imager 220. May be a part.

  11A-B, 11C-D show a non-limiting example of such a multi-image light-modulating display element 220, which includes a predetermined pixel row or pixel in a 2D array of pixels on the display element 220. A predetermined set of individual pixels, such as a set of columns, is constructed by incorporating micro-optical elements that direct or modulate the light emitted from each pixel in a predetermined unique direction.

  FIGS. 11A-B, 11C-D show examples in which a multi-image display element 220 is designed to modulate two images simultaneously, with the first and second images being emitted in different directions from the surface of the display element 220, respectively. Show. If such a display element 220 is used in the context of the split exit pupil HUD design architecture of FIG. 2, the modulated (described above) first image will be in a far field distance (eg, from the eye box 250 of the HUD system) (eg, Generating a first virtual image viewable at approximately 2.5 m), while the second modulated image is a second virtual image viewable at near field distance (eg, approximately 0.5 m). Generate an image. These two viewable virtual images can be modulated simultaneously by the multi-image split exit pupil HUD system, and the viewer of the HUD system can view in the plane of the vertical axis the line of sight of the multiple exit pupil HUD system displays. By simply re-orienting the two virtual images modulated by the element 220 by an angle proportional to the angular inclination (or separation) of the modulation direction of the two virtual images, the first virtual image or the second virtual image can be selectively viewed.

  11A and 11B show top and side views of a display element 220 in one embodiment of the present invention, in which multiple display elements 220 of a split exit pupil HUD system have their light apertures divided by two. Partitioning the display pixels of a group, for example, odd and even rows (where one group of pixels, ie, the odd rows of pixels, modulates the first image and the second group of pixels, ie, the even number of pixels, The rows of pixels modulate the second image) to thereby modulate the first and second images. Such directional modulation capabilities of the display elements 220 of the HUD system cause the micro-optical or micro-lens elements associated with each image modulation pixel group to directionally modulate the light emitted from the associated pixels in a predetermined image direction. This can be achieved by designing For example, in the case shown in FIGS. 11A and 11B, the micro-optics associated with the odd rows of pixels form a first image by directing light emitted from the associated group of pixels; On the other hand, the micro-optical elements associated with the even rows of pixels form a second image by directing light emitted from the group of associated pixels. Note that, for each image in FIGS. 11A-11D, the light rays are shown as being parallel, but in practice the light rays generally fan out from the imager 220, thereby expanding the image size as needed. Or enlarged. Pixel emission angles can be achieved through the use of non-telecentric micro-optical lens elements in the form of non-telecentric QPI® imagers, as described in further detail below.

  When using the above-described single-image split exit pupil HUD design architecture, the plurality of imagers 220 modulate the same two images in different directions, respectively, and collectively modulate the same in the collective eye box 250 of the split exit pupil HUD system. Presents both virtual images, where each of the resulting two modulated virtual images is viewable over the collective eyebox 250, but in a different vertical (or azimuthal) direction.

  In a further multi-image HUD system shown in FIGS. 11C and 11D, the plurality of display elements 220 of the split exit pupil multi-image HUD system each include two regions or areas of pixels, i.e., pixels in the illustrated example. It has a light aperture that is divided into an upper region and a lower region of the pixel. In this embodiment, the two images that are modulated in different directions are each modulated by a single dedicated pixel area. For example, as shown in FIGS. 11C and 11D, the upper region of the pixels of the light aperture of the display element 220 (which may be any user-defined portion of the set of pixels of the imager) constitutes the upper region of the pixels. A micro-optical element designed to direct the light emitted from each pixel of the display element 220 to form a first image as defined above, while the display element The lower region of the pixel of the light aperture of 220 directs the light emitted from each pixel of the display element 220 that constitutes the lower region of the pixel to form a second image as defined above. It has a micro-optical element designed to form. Pixel emission angles can be provided by the use of non-telecentric micro-optics in the form of non-telecentric imagers 220, as described in more detail below.

  FIG. 12 illustrates one preferred embodiment of the multiple image split exit pupil HUD system of the present invention. As shown in FIG. 12, a plurality of display elements (or imagers) 220 may each modulate two virtual images, where a first image is modulated upward and a second image is modulated downward. Is done.

  The plurality of display elements 220 simultaneously modulate both the first and second images to angularly fill the multi-image split exit pupil HUD system eyebox 250 as shown in FIG. After being collimated by the concave mirror 230 and reflected by the windshield to the eyebox 250, the collimated light beams constituting the first and second two images modulated (generated) by the plurality of display elements 220 are , At two different tilt angles in the eyebox 250, which allows the viewer of the multi-image split exit pupil HUD system to focus on two separate and simultaneously modulated virtual images, where The first virtual image is viewable in the far field 260-1 and the second virtual image is viewable in the near field 260-2, so that the two virtual images can be viewed by the plurality of display elements 220. By an angle 220-3 proportional to the direction separation angle 220-4 between the two modulated images. (Azimuth) are angularly separated in the direction.

  These two virtual images are at different first and second virtual distances because their ray bundles are collimated at different levels (to different degrees). The collimation of the concave mirror 230 is designed to achieve a distance of the far-field virtual image from the eyebox 250. The micro-optics of the non-telecentric QPI® imager, described below as an example of a specific embodiment, provides additional collimation of the light emitted from each pixel associated with the non-telecentric QPI® element. Designed to be introduced. Thus, the complex collimation achieved by the non-telecentric micro-optics in cooperation with the concave mirror 230 achieves a far-field virtual image distance and a near-field virtual image distance from the eyebox 250, thereby providing a multi-image HUD Can simultaneously display both the far-field virtual image and the near-field virtual image.

  As shown in FIG. 13, the viewer of the multi-image split exit pupil HUD system simply reorients the line of sight by angle 220-3 in the vertical (azimuth) direction, and the first and second modulated by the HUD system. One of the two virtual images can be viewed (or focused on) (see also FIG. 12). Since these two virtual images are independently and separately modulated by two separate groups of pixels that make up the display element (imager) 220, the first and second images displayed to the viewer, respectively, , Different information that may be of interest to the viewer.

  FIG. 13 also shows the nominal position of the first and second two virtual images modulated by the multi-image split exit pupil HUD system, where the far-field virtual image shows the viewer. In a non-limiting example, focus can be achieved at a distance of approximately 2.5 m (approximately at the end of the front hood of the vehicle), and the near-field virtual image shows the viewer at a distance of approximately 0.5 m Focus can be achieved (approximately at the outer lower edge of the vehicle windshield).

  It should be noted that the multi-image handling capability of the HUD described above advantageously does not result in an increase in volume aspects of the multi-image split exit pupil HUD system outlined in FIG. The interface 710, control functions 720, and uniformity loop 730 of the display element (imager) 220 also remain unchanged, as shown in FIG.

The main differences in the implementation and design method of the multiple image split exit pupil HUD system compared to the described single image split exit pupil HUD system are as follows:
1. As described in the above embodiments, multiple display elements (imagers) 220 have the ability to modulate multiple images in different directions.
2. The vertical field of view (FOV) of the multi-image split exit pupil HUD system is angularly divided into two directional regions so that two angularly separated images can be modulated simultaneously.
3. An image input 715 to a plurality of display elements (imagers) 220 consists of two images, each (digitally) addressed to a corresponding pixel group described in the above embodiment.

  FIG. 14 illustrates an exemplary implementation of the non-telecentric QP imager referred to above, wherein the non-telecentric micro-optics 1250-1 can be implemented as a refractive optical element (ROE) and used therewith. Thus, a near-field virtual image can be provided by orienting the light output of selected pixels at a generally oblique angle with respect to the surface of the display element 220.

  In this embodiment of FIG. 14, the directional modulation aspect of the pixel-level refractive non-telecentric micro-optical element 1250-1 is a decentered microlens 1250 formed of a continuous layer of dielectric materials 1310, 1320 having different refractive indices. -1 can be realized. FIG. 14 is a schematic cross-sectional view of a display element 220 including a plurality of non-telecentric refractive micro-optical elements 1250-1. In this embodiment, the array of pixel-level non-telecentric micro-optics 1250-1 is formed using silicon lithography, etching, and deposition techniques, silicon oxide for the low index layer 1310 and silicon oxide for the high index layer 1320. May be monolithically fabricated at the wafer level as multiple layers of a semiconductor dielectric material such as silicon nitride. As shown in FIG. 14, an array of pixel-level micro-optics 1250-1 is sequentially (sequentially) deposited to form a plurality of layers, ie, refractive surfaces of pixel-level micro-optics 1250-1. The optical element is implemented using dielectric materials 1310, 1320 having different refractive indices, and the optical element can be refracted microscopically over the microlens array as needed to achieve the desired non-telecentricity and image projection direction. The center position of the lens element changes gradually.

  FIG. 15 shows another exemplary implementation of the non-telecentric QPI® imager referred to above, wherein the non-telecentric micro-optics 1250-2 is implemented as a tilted refractive optic (ROE). , Again, as needed, progressively across the microlens array to achieve the desired non-telecentricity and image projection direction, and use this to reduce the light output of the selected pixel. By orienting at a generally oblique angle with respect to the surface of the imager 220, a near-field image or a second image can be provided. In this embodiment, the directional modulation aspect of the pixel-level refractive non-telecentric micro-optical element 1250-2 is a tilted microlens 1250-2 formed of a continuous layer of dielectric materials 1410, 1420 having different refractive indices. It can be realized by using

  FIG. 15 is a side view of a display element 220 comprising a plurality of tilted refractive micro-optical elements 1250-2. In this embodiment, an array of pixel-level non-telecentric micro-optics 1250-2 is fabricated using semiconductor lithography, etching, and deposition techniques, using silicon oxide for the low index layer 1410 and silicon oxide for the high index layer 1420. It may be fabricated monolithically at the wafer level as multiple layers of a semiconductor dielectric material such as silicon nitride. As shown in FIG. 15, an array of pixel-level non-telecentric micro-optics 1250-2 is sequentially (sequentially) formed to form a plurality of layers, ie, refractive surfaces of pixel-level non-telecentric micro-optics 1250-2. ) Can be achieved using deposited dielectric materials 1410, 1420 having different indices of refraction.

  Thus, the present invention has a number of aspects, which may be implemented alone or in various combinations or sub-combinations as desired. While certain preferred embodiments of the invention have been disclosed and described by way of example, and not by way of limitation, those skilled in the art will appreciate that they do not depart from the spirit and scope of the invention as defined by the following claims. It will be understood that various changes in form and detail can be made to the above embodiments.

Claims (9)

Module electrical properties, each module has its own,
Solid-state light-emitting pixel array imaging device,
First and second virtual images viewable within an eyebox segment including a concave mirror arranged to collimate, magnify, and reflect the first and second images generated by the solid state pixel array imager. A vehicle windshield for forming a
A plurality of modules are arranged such that the eyebox segments combine to provide a head-up display having an aggregate eyebox that is larger than the eyebox segment of each module. The collective eyebox is located at the nominal head position of the driver of the vehicle,
The solid state light emitting pixel array imager includes a first set of pixels associated with a respective first set of micro-optical elements and a second set of pixels associated with a respective second set of micro-optical elements. Including
The first set of micro-optics is configured to project an image from a respective first set of pixels outwardly from a surface of the solid state light emitting pixel array imager, thereby providing a second image from the collective eyebox. A first virtual image that can be viewed at a distance of 1 is generated,
A second set of micro-optics configured to project the image from each second set of pixels in a direction tilted downward with respect to the first image, wherein a second virtual image is generated. And a vehicle head-up display configured to be viewed at a second distance from the collective eye box.   The head-up display according to claim 1, wherein the first distance is a far-field distance and the second distance is a near-field distance.   The first set of pixels comprises a user-defined first set of pixels of the solid state pixel array imaging device, and the second set of pixels comprises a user-defined second set of the solid state pixel array imaging device. The head-up display according to claim 1, wherein the head-up display is constituted by the following pixels.   The first set of pixels is composed of odd-numbered rows of pixels of the solid-state pixel array imager, and the second set of pixels is composed of even-numbered rows of the solid-state pixel array imager. The head-up display according to claim 1, wherein:   The first set of pixels is comprised of even-numbered rows of the solid-state pixel array imaging device, and the second set of pixels is comprised of odd-numbered rows of the solid-state pixel array imaging device. The head-up display according to claim 1, wherein:   The first set of pixels comprises pixels that make up at least 50% of the pixel area of the solid state light emitting pixel array imager, and the second set of pixels comprises the remaining pixels of the solid state light emitting pixel array imager. 2. The head-up display according to claim 1, wherein the head-up display is constituted by an area.   The first set of pixels is configured from an upper region of the solid-state light-emitting pixel array imaging device, and the second set of pixels is configured from a lower region of the solid-state light-emitting pixel array imaging device. The head-up display according to claim 1.   The head-up display of claim 1, wherein the number of eyebox segments and modules is a user defined number of eyebox segments and modules.   The first set of pixels is comprised of a first set of user-defined pixels of the solid state pixel array imager, and the second set of pixels is a user-defined set of pixels of the solid state pixel array imager. 2. The head-up display according to claim 1, wherein the head-up display is composed of a second set, wherein the number of eye box segments and modules is a user defined number of eye box segments and modules.