JP2019174519A - Display unit, display system, moving body, display intensity control method, and program - Google Patents

Abstract

To improve visibility of display information by suppressing variation in display intensity which is undesirable to an observer 3.SOLUTION: A display unit according to one embodiment of the present invention is a display unit 10A which displays a virtual image 45 (one example of display information) in front of a moving body, and acquires intensity information 450 representing intensity of an intensity detection region 300 (one example of a circumferential region) including at least a part of a display background region 350 (one example of a display region) as a background of the virtual image 45, and stores the acquired intensity information 450 in an intensity information management table 400 (one example of a storage region). Then the display unit 10A determines, based upon a representative value of the stored intensity information 450, display intensity information 500 representing display intensity of the virtual image 45, and uses the determined display intensity information 500 to display the virtual image 45.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a display device, a display system, a moving body, a display luminance control method, and a program.

  In a moving body such as a vehicle, a display device such as a HUD (head-up display) is used as an application that allows a driver (observer) to visually recognize various information (vehicle information, warning information, navigation information, etc.) with a small amount of line of sight. ing. In a display device mounted on a vehicle, a technique for controlling the display luminance is known so that the driver can easily recognize it according to the luminance around the vehicle.

  On the other hand, when the display brightness is made to follow the change in the brightness around the vehicle, the display flickers due to a sudden change in the surrounding brightness (for example, when sunlight enters), and so on. It is conceivable that the visibility of the display is impaired. Therefore, a technique is known in which the visibility of a driver's display is improved by reducing the flickering of the display due to a sudden change in luminance around the vehicle.

  For example, in Patent Document 1, in order to prevent the visibility of visual information from deteriorating, the brightness of a plurality of points in the driver's front landscape is estimated, and the driver's front is determined based on the estimated brightness of the plurality of points. The content which controls the brightness | luminance of the display image displayed within a visual field is disclosed.

  However, for example, a region (for example, a peripheral region) for estimating the luminance in the front landscape of the driver (for example, an observer) and a region (for example, a display region) for displaying a display image (for example, display information) are completely present. May not match. In such a case, according to the conventional method, the change in display luminance is affected by the change in luminance outside the display area. Therefore, although the brightness in the display area has not changed, the display brightness also changes following the change in brightness due to the peripheral area, so that the visibility of display information is impaired.

  A display device according to the present invention is a display device that displays display information in front of a moving body, and acquires luminance information indicating luminance of a peripheral region including at least a part of a display region that is a background of the display information. An acquisition unit; a storage control unit that stores the acquired luminance information in a storage area; and a determination unit that determines display luminance information indicating the display luminance of the display information based on a representative value of the stored luminance information. The display information is displayed using the determined display luminance information.

  ADVANTAGE OF THE INVENTION According to this invention, the visibility of display information can be improved by suppressing the change of the display brightness undesirable for an observer.

It is a figure which shows an example of the system configuration | structure of the display system which concerns on embodiment. It is a figure which shows an example of the specific structure of the light source device which concerns on embodiment. It is a figure which shows an example of the specific structure of the optical deflection | deviation apparatus which concerns on embodiment. It is a figure which shows an example of the specific structure of the screen which concerns on embodiment. It is a figure for demonstrating the difference in the effect | action by the difference in the magnitude relationship of an incident light beam diameter and a lens diameter in a microlens array. It is a figure for demonstrating the correspondence of the mirror of an optical deflection | deviation apparatus, and a scanning range. It is a figure which shows an example of the scanning line locus | trajectory at the time of two-dimensional scanning. It is a figure for demonstrating the outline of the display system which concerns on 1st Embodiment. It is a figure for demonstrating the outline of the brightness | luminance detection area | region in the display system which concerns on 1st Embodiment. It is a figure for demonstrating an example of the relationship between the brightness | luminance detection area | region and display background area | region in the display system which concerns on 1st Embodiment. It is a figure which shows an example of the hardware constitutions of the display apparatus which concerns on 1st Embodiment. It is a figure which shows an example of a function structure of the display apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the detailed functional structure of the display brightness control part which concerns on 1st Embodiment. It is a figure which shows an example of the brightness | luminance information management table which concerns on 1st Embodiment. It is a flowchart which shows an example of the control process of the display brightness in the display apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the specific example of the influence of the periodic noise in an observer's visual field. It is a figure for demonstrating an example of the relationship between the brightness | luminance detection area | region and display background area which concern on the modification of 1st Embodiment. It is a flowchart which shows an example of the control process of the display brightness in the display apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

● Embodiment ●
System Configuration FIG. 1 is a diagram illustrating an example of a system configuration of a display system according to the embodiment. The display system 1 shown in FIG. 1 is a system that causes the observer 3 to visually recognize display information by projecting projection light projected from the display device 10 onto a transmission / reflection member. The display information is image information that is superimposed and displayed as a virtual image 45 in the field of view of the observer 3.

  The display system 1 is provided in, for example, a moving body such as a vehicle, an aircraft, or a ship, or a non-moving body such as an operation simulation system or a home theater system. This embodiment demonstrates the case where the display system 1 is equipped with the motor vehicle which is an example of a mobile body. The usage pattern of the display system 1 is not limited to this.

  The display system 1 is, for example, navigation information (for example, vehicle speed, route information, distance to a destination, current location name, presence / absence of an object (object) in front of the vehicle, and the like necessary for maneuvering the vehicle via the windshield 50. The viewer 3 (operator) visually recognizes the position, a speed limit sign, and information such as traffic jam information. In this case, the windshield 50 functions as a transmission / reflection member that transmits a part of the incident light and reflects at least a part of the remaining part. The distance from the viewpoint position of the observer 3 to the windshield 50 is about several tens of cm to 1 m.

  The display system 1 includes a display device 10, a free-form curved mirror 30, and a windshield 50. The display device 10 is, for example, a head-up display device (HUD device) mounted on an automobile that is an example of a moving object. The display device 10 is arranged at an arbitrary position in accordance with the interior design of the automobile. The display apparatus 10 may be arrange | positioned under the dashboard of a motor vehicle, for example, and may be embedded in the dashboard.

  The display device 10 includes a light source device 11, a light deflection device 13, and a screen 15. The light source device 11 is a device that irradiates laser light emitted from a light source to the outside of the device. For example, the light source device 11 may irradiate a laser beam obtained by combining laser beams of three colors of R, G, and B. The laser light emitted from the light source device 11 is guided to the reflection surface of the light deflection device 13. The light source device 11 includes a semiconductor light emitting element such as an LD (Laser Diode) as a light source. The light source is not limited to this, and may include a semiconductor light emitting element such as an LED (light emitting diode).

  The optical deflection device 13 is a device that changes the traveling direction of laser light using MEMS (Micro Electro Mechanical Systems) or the like. The optical deflector 13 includes scanning means such as a single minute MEMS mirror that swings about two orthogonal axes, or a mirror system that includes two MEMS mirrors that swing or rotate about one axis. Configured using. The laser beam emitted from the light deflecting device 13 is scanned on the screen 15. The light deflecting device 13 is not limited to the MEMS mirror, and may be configured using a polygon mirror or the like.

  The screen 15 is a diverging member having a function of diverging laser light at a predetermined divergence angle. The screen 15 is configured by a transmissive optical element having a light diffusing effect such as a microlens array (MLA) or a diffusing plate in the form of EPE (Exit Pupil Expander), for example. The screen 15 may be configured by a reflective optical element having a light diffusion effect such as a micromirror array. The screen 15 scans the screen 15 with the laser beam emitted from the light deflecting device 13, thereby forming an intermediate image 40 that is a two-dimensional image on the screen 15.

  Here, the projection method of the display device 10 is a “panel method” in which the intermediate image 40 is formed by an imaging device such as a liquid crystal panel, a DMD panel (digital mirror device panel), or a fluorescent display tube (VFD), and the light source device 11 emits light. There is a “laser scanning method” in which an intermediate image 40 is formed by scanning the laser beam with a scanning unit.

  The display device 10 according to the embodiment employs the latter “laser scanning method”. In the “laser scanning method”, light emission or non-light emission can be assigned to each pixel, so that generally a high-contrast image can be formed. The display device 10 may use a “panel method” as a projection method.

  The virtual image 45 projected onto the free-form surface mirror 30 and the windshield 50 by the laser light (light beam) emitted from the screen 15 is enlarged from the intermediate image 40 and displayed. The free-form surface mirror 30 is designed and arranged so as to cancel out the inclination, distortion, misalignment and the like of the image due to the curved shape of the windshield 50. The free-form surface mirror 30 may be installed to be rotatable about a predetermined rotation axis. Thereby, the free-form surface mirror 30 can adjust the reflection direction of the laser beam (light beam) emitted from the screen 15 and change the display position of the virtual image 45.

  Here, the free-form surface mirror 30 is designed using existing optical design simulation software so as to have a constant light condensing power so that the imaging position of the virtual image 45 becomes a desired position. The display device 10 sets the condensing power of the free-form surface mirror 30 so that the virtual image 45 is displayed at a position (depth position) of 1 m or more and 30 m or less (preferably 10 m or less) from the viewpoint position of the observer 3. Is done. Note that the free-form surface mirror 30 may be a concave mirror or other element having a condensing power. The free-form curved mirror 30 is an example of an imaging optical system.

  The windshield 50 is a transmission / reflection member having a function (partial reflection function) of transmitting a part of the laser light (light beam) and reflecting at least a part of the remaining part. The windshield 50 functions as a semi-transparent mirror that allows the observer 3 to visually recognize the scenery in front and the virtual image 45. The virtual image 45 is image information for causing the observer 3 to visually recognize vehicle information (speed, travel distance, etc.), navigation information (route guidance, traffic information, etc.), warning information (collision warning, etc.), and the like. The transmission / reflection member may be a front windshield provided separately from the windshield 50. The windshield 50 is an example of a reflecting member.

  The virtual image 45 may be displayed so as to overlap the scenery in front of the windshield 50. Further, the windshield 50 is not flat but curved. Therefore, the imaging position of the virtual image 45 is determined by the curved surface of the free-form surface mirror 30 and the windshield 50. The windshield 50 may use a semi-transmission mirror (combiner) as an individual transmission reflection member having a partial reflection function.

  With such a configuration, the laser light (light beam) emitted from the screen 15 is projected toward the free-form surface mirror 30 and reflected by the windshield 50. The observer 3 can visually recognize the virtual image 45 in which the intermediate image 40 formed on the screen 15 is enlarged by the light reflected by the windshield 50.

Light Source Device FIG. 2 is a diagram illustrating an example of a specific configuration of the light source device according to the embodiment. The light source device 11 includes light source elements 111R, 111G, and 111B (hereinafter referred to as the light source element 111 when there is no need to distinguish them), coupling lenses 112R, 112G, and 112B, apertures 113R, 113G, and 113B, and a combining element 114. , 115 and 116, and the lens 117.

  The three color (R, G, B) light source elements 111R, 111G, 111B are, for example, LDs (Laser Diodes) each having one or a plurality of light emitting points. The light source elements 111R, 111G, and 111B emit laser beams (light beams) having different wavelengths λR, λG, and λB (for example, λR = 640 nm, λG = 530 nm, and λB = 445 nm).

  Each emitted laser beam (light beam) is coupled by coupling lenses 112R, 112G, and 112B, respectively. The coupled lasers (light beams) are shaped by the apertures 113R, 113G, and 113B, respectively. The apertures 113R, 113G, and 113B have shapes (for example, a circle, an ellipse, a rectangle, and a square) according to predetermined conditions such as a divergence angle of laser light (light flux).

  Each laser beam (light beam) shaped by the apertures 113R, 113G, and 113B is synthesized by the three synthesis elements 114, 115, and 116. The synthesizing elements 114, 115, and 116 are plate-like or prism-like dichroic mirrors that reflect or transmit laser light (light flux) according to the wavelength, and synthesize them into one light flux. The synthesized light flux passes through the lens 117 and is guided to the light deflecting device 13.

FIG. 3 is a diagram illustrating an example of a specific configuration of the light deflection apparatus according to the embodiment. The optical deflection device 13 is a MEMS mirror manufactured by a semiconductor process, and includes a mirror 130, a meandering beam portion 132, a frame member 134, and a piezoelectric member 136. The light deflection device 13 is an example of a scanning unit.

  The mirror 130 has a reflection surface that reflects the laser light emitted from the light source device 11 toward the screen 15. The light deflecting device 13 forms a pair of meandering beam portions 132 with the mirror 130 interposed therebetween. The meandering beam portion 132 has a plurality of folded portions. The folded portion is composed of first beam portions 132a and second beam portions 132b that are alternately arranged. The meandering beam portion 132 is supported by the frame member 134. The piezoelectric member 136 is disposed so as to connect the adjacent first beam portion 132a and the second beam portion 132b. The piezoelectric member 136 applies different voltages to the first beam portion 132a and the second beam portion 132b, and generates warpage in each of the beam portions 132a and 132b.

  Thereby, the adjacent beam parts 132a and 132b bend in different directions. The mirror 130 rotates in the vertical direction about the left-right axis as the deflection is accumulated. With such a configuration, the optical deflecting device 13 can perform optical scanning in the vertical direction with a low voltage. Optical scanning in the horizontal direction with the vertical axis as the center is performed by resonance using a torsion bar or the like connected to the mirror 130.

Screen FIG. 4 is a diagram illustrating an example of a specific configuration of the screen according to the embodiment. The screen 15 forms an image of the laser light emitted from the LD 1007 constituting a part of the light source device 11. The screen 15 is a diverging member that diverges at a predetermined divergence angle. The screen 15 is an example of an optical element.

  The screen 15 shown in FIG. 4 has a microlens array structure in which a plurality of hexagonal microlenses 150 are arranged without gaps. The width of the microlens 150 (distance between two opposing sides) is about 200 μm. The screen 15 can arrange a plurality of microlenses 150 at a high density by making the shape of the microlenses 150 hexagonal.

  Note that the shape of the microlens 150 is not limited to a hexagon, and may be, for example, a quadrangle, a triangle, or the like. Further, the structure in which the plurality of microlenses 150 are regularly arranged is illustrated, but the arrangement of the microlenses 150 is not limited to this, and for example, the centers of the microlenses 150 are eccentric to each other and irregularly arranged. It is good also as an arrangement. When such an eccentric arrangement is adopted, the microlenses 150 have different shapes.

  FIG. 5 is a diagram for explaining the difference in action due to the difference in the magnitude relationship between the incident light beam diameter and the lens diameter in the microlens array. In FIG. 5A, the screen 15 includes an optical plate 151 in which microlenses 150 are arranged. When the incident light 152 is scanned on the optical plate 151, the incident light 152 is diverged by the microlens 150 to become divergent light 153. The screen 15 can diverge the incident light 152 at a desired divergence angle 154 by the structure of the microlens 150. The period 155 of the microlens 150 is designed to be larger than the diameter 156 a of the incident light 152. Thereby, the screen 15 suppresses generation | occurrence | production of interference noise, without causing interference between lenses.

  FIG. 5B shows an optical path of diverging light when the diameter 156 b of the incident light 152 is twice as large as the period 155 of the microlens 150. Incident light 152 is incident on two microlenses 150a and 150b to generate diverging light 157 and 158, respectively. At this time, since two divergent lights exist in the region 159, light interference may occur. When this interference light enters the observer's eyes, it is visually recognized as interference noise.

  Considering the above, in order to reduce speckle, the period 155 of the microlens 150 is designed to be larger than the diameter 156 of the incident light. In addition, although FIG. 5 demonstrated in the form of the convex lens, the same effect shall also be obtained in the form of a concave lens.

  FIG. 6 is a diagram for explaining the correspondence between the mirror of the optical deflector and the scanning range. The light emission intensity, lighting timing, and optical waveform of each light source element of the light source device 11 are controlled by the FPGA 1001. Each light source element of the light source device 11 is driven by an LD driver 1008 to emit laser light. As shown in FIG. 6, the laser light emitted from each light source element and combined in the optical path is two-dimensionally deflected around the α axis and the β axis by the mirror 130 of the optical deflector 13 and scanned through the mirror 130. The screen 15 is irradiated as light. That is, the screen 15 is two-dimensionally scanned by main scanning and sub-scanning by the light deflecting device 13.

  The scanning range is the entire range that can be scanned by the light deflecting device 13. Scanning light scans the scanning range of the screen 15 in the main scanning direction (X-axis direction) at a fast frequency of about 2 to 40,000 Hz, and in the sub-scanning direction at a slow frequency of about several tens of Hz. One-way scanning is performed in the (Y-axis direction). That is, the light deflecting device 13 performs a raster scan on the screen 15. In this case, the display device 10 can perform drawing or display of a virtual image for each pixel by performing light emission control of each light source element according to the scanning position (scanning light position).

  The time for drawing one screen, that is, the scanning time for one frame (one cycle of two-dimensional scanning) is several tens of msec because the sub-scanning cycle is several tens Hz as described above. For example, when the main scanning period is 20000 Hz and the sub-scanning period is 50 Hz, the scanning time for one frame is 20 msec.

  FIG. 7 is a diagram illustrating an example of a scanning line locus during two-dimensional scanning. As shown in FIG. 7, the screen 15 has an image area 61 (effective scanning area) on which the intermediate image 40 is drawn (irradiated with light modulated according to image data) and a frame area surrounding the image area 61. 62.

  The scanning range is a range in which the image area 61 and a part of the frame area 62 on the screen 15 (a part near the outer edge of the image area 61) are combined. In FIG. 7, the trajectory of the scanning line in the scanning range is indicated by a zigzag line. In FIG. 7, for the sake of convenience, the number of scanning lines is made smaller than the actual number.

  As described above, the screen 15 is composed of a transmissive optical element having a light diffusion effect such as a microlens array. The image area 61 does not have to be a rectangle or a plane, but may be a polygon or a curved surface. The screen 15 may be a flat plate or a curved plate that does not have a light diffusion effect. Furthermore, the image area 61 can be a reflective element having a light diffusion effect, such as a micromirror array, according to the device layout.

  The screen 15 includes a synchronization detection system 60 including a light receiving element in a peripheral region of the image region 61 in the scanning range (a part of the frame region 62). In FIG. 7, the synchronization detection system 60 is arranged at the corner of the image area 61 on the −X side and the + Y side. The synchronization detection system 60 detects the operation of the optical deflecting device 13 and outputs a synchronization signal for determining the scan start timing and the scan end timing to the FPGA 1001.

● First embodiment ●
Overview The configuration of the display system 1A according to the first embodiment will be described next with reference to FIGS. First, the outline of the display system 1A according to the first embodiment will be described with reference to FIGS.

  FIG. 8 is a diagram for explaining the outline of the display system according to the first embodiment. The display system 1A illustrated in FIG. 8 can improve the visibility of display information (virtual image 45) by suppressing a change in display luminance that is undesirable for the observer 3.

  The display system 1A includes a luminance sensor 70 in addition to the configuration of the display system 1 shown in FIG. The luminance sensor 70 is a sensing device provided to detect the luminance (illuminance) of the road surface in front of the vehicle constituting the display system 1. As shown in FIG. 8, the luminance sensor 70 is installed, for example, on an upper part of a windshield 50 of an automobile.

  The luminance sensor 70 may be a single photoelectric conversion element or the like, may be a two-dimensional array sensor, or may be an imaging element such as an in-vehicle camera. As shown in FIG. 9, the luminance sensor 70 is installed at a position where the luminance (illuminance) of an area including the road surface ahead of the vehicle (luminance detection area 300) can be detected.

  Note that the installation position of the luminance sensor 70 is not limited to the example illustrated in FIG. 8, and may be installed on a dashboard of an automobile, for example. In addition, the luminance sensor 70 may be replaced by an illuminance sensor provided to realize an autolight function of the automobile or a rain sensor provided to operate the wiper of the automobile in response to raindrops. Furthermore, although this embodiment demonstrates the example in which the luminance sensor 70 is provided separately from 10 A of display apparatuses, the luminance sensor 70 may be incorporated in 10 A of display apparatuses.

  FIG. 10 is a diagram for explaining an example of the relationship between the luminance detection region and the display background region in the display system according to the first embodiment. The image shown in FIG. 10 is a landscape image in front of the automobile viewed by the driver (observer 3) of the automobile through the windshield 50. FIG. 10 shows the relationship between the luminance detection area 300 and the display background area 350 on the landscape image visually recognized by the observer 3.

  The display background area 350 is an area in which display information (virtual image 45) output from the display device 10A is displayed superimposed on a landscape image (background image). That is, the driver of the automobile (observer 3) can visually recognize the virtual image 45 in the area of the display background area 350. The display background area 350 includes display information displayed by the display device 10A and a road surface in front of the vehicle that serves as a background image of the display information. The background image of the display information is not limited to the road surface, and may be a landscape around the vehicle such as an outer wall of a building located in front of the vehicle, a sign, or the sky.

  The luminance detection area 300 includes a display background area 350, a road surface around the display background area 350, an outer wall of a building located in front of the automobile, a landscape such as a sign or the sky. Here, the luminance detection region 300 is a region including a spatial section of a space where the viewer 3 visually recognizes display information displayed by the display device 10A.

  The display device 10A monitors the luminance change of the display background region 350, which is a region where display information is superimposed, by sampling the luminance around the automobile on which the display device 10A is mounted. The luminance detection area 300 is an example of a peripheral area. The display background area 350 is an example of a display area.

  A luminance detection area 300 shown in FIG. 10 includes a display background area 350. Further, an area outside the display background area 350 exists within the luminance detection area 300. Since the area outside the display background area 350 is not an area where display information is superimposed, it is an area that is not originally intended for sampling of luminance change.

  Here, for example, in a region within the luminance detection region 300 but outside the display background region 350, a change in luminance with a relatively short period (hereinafter, referred to as blinking of a direction indicator of a preceding vehicle) It is conceivable that a periodic noise) occurs. In this case, when the display brightness of the display information is determined based on the brightness data detected in the brightness detection area 300, the display information (virtual image 45) is displayed even though the background brightness in the display background area 350 is constant. ) Will change. Such a change in display luminance that does not match the change in the background luminance of the display background region 350 makes the viewer 3 feel uncomfortable, and as a result, impairs the visibility of display information.

  In addition, for example, when periodic noise that repeatedly blinks at high speed such as a direction indicator occurs in the display background area 350, the display brightness changes to the background brightness with respect to the actual background brightness change. It changes with a delay of a predetermined time required for the process for following. Therefore, even for periodic noise in the display background region 350, the viewer 3 feels uncomfortable due to the influence of the time lag of the change in display luminance with respect to the change in background luminance, and the visibility of display information is impaired.

  Therefore, the display system 1A according to the first embodiment does not intentionally follow the display brightness of the display information with respect to the periodic brightness noise detected in the brightness detection region 300. A change can be reduced and the visibility of display information can be improved.

Hardware Configuration FIG. 11 is a diagram illustrating an example of a hardware configuration of the display device according to the first embodiment. The hardware configuration shown in FIG. 11 may have the same configuration in each embodiment, and components may be added or deleted as necessary.

  The display device 10A includes a control device 17 for controlling the operation of the display device 10A. The control device 17 is a controller such as a substrate or an IC chip mounted inside the display device 10A. The control device 17 includes an FPGA (Field-Programmable Gate Array) 1001, a CPU (Central Processing Unit) 1002, a ROM (Read Only Memory) 1003, a RAM (Random Access Memory) 1004, an I / F (Interface) 1005, and a bus line 1006. , LD driver 1008, MEMS controller 1010, and motor driver 1012.

  The FPGA 1001 is an integrated circuit that can be changed by the designer of the display device 10A. The LD driver 1008, the MEMS controller 1010, and the motor driver 1012 generate drive signals in response to control signals from the FPGA 1001. The CPU 1002 is an integrated circuit that performs processing for controlling the entire display device 10A. The ROM 1003 is a storage device that stores a program for controlling the CPU 1002. For example, the display device 10A implements the display brightness control method according to the present invention by the CPU 1002 executing the program according to the present invention. The RAM 1004 is a storage device that functions as a work area for the CPU 1002.

  An I / F 1005 is an interface for communicating with an external device. The I / F 1005 is connected to a CAN (Controller Area Network) of an automobile, for example. The I / F 1005 is connected to the luminance sensor 70. The luminance sensor 70 transmits sensing data (luminance information) to the control device 17 via the I / F 1005.

  The LD 1007 is, for example, a semiconductor light emitting element that constitutes a part of the light source device 11. The LD driver 1008 is a circuit that generates a drive signal for driving the LD 1007. The MEMS 1009 is a device that constitutes a part of the light deflection apparatus 13 and displaces the scanning mirror. The MEMS controller 1010 is a circuit that generates a drive signal for driving the MEMS 1009. The motor 1011 is an electric motor that rotates the rotation shaft of the free-form curved mirror 30. The motor driver 1012 is a circuit that generates a drive signal for driving the motor 1011.

Functional Configuration FIG. 12 is a diagram illustrating an example of a functional configuration of the display device according to the first embodiment. Functions realized by the display device 10 </ b> A include a vehicle information receiving unit 171, an external information receiving unit 172, a display brightness control unit 178, an image generation unit 173, and an image display unit 174.

  The vehicle information receiving unit 171 has a function of receiving automobile information (information such as speed and travel distance) from CAN or the like. The vehicle information receiving unit 171 is realized by the processing of the I / F 1005 and the CPU 1002 illustrated in FIG. 11, a program stored in the ROM 1003, and the like.

  The external information receiving unit 172 has a function of receiving information outside the vehicle (position information from the GPS, route information from the navigation system, traffic information, etc.) from the external network. The external information receiving unit 172 is realized by the processing of the I / F 1005 and the CPU 1002 illustrated in FIG. 11, a program stored in the ROM 1003, and the like.

  The display brightness control unit 178 has a function of controlling the display brightness of display information output from the display device 10A. The display brightness control unit 178 is realized by the processing of the I / F 1005 and the CPU 1002 illustrated in FIG. 11, a program stored in the ROM 1003, and the like. The detailed configuration of the display brightness control unit 178 will be described later.

  The image generation unit 173 displays display information (image information) for displaying the intermediate image 40 and the virtual image 45 based on information input by the vehicle information reception unit 171, the external information reception unit 172, and the display luminance control unit 178. It is a function to generate. The image generation unit 173 is realized by the processing of the CPU 1002 illustrated in FIG. 11, a program stored in the ROM 1003, and the like.

  The image display unit 174 forms an intermediate image 40 on the screen 15 based on the display information generated by the image generation unit 173, and projects the laser light (light beam) constituting the intermediate image 40 toward the windshield 50. The virtual image 45 is displayed. The image display unit 174 is realized by the processing of the CPU 1002, the FPGA 1001, the LD driver 1008, the MEMS controller 1010 and the motor driver 1012 illustrated in FIG. 11, a program stored in the ROM 1003, and the like.

  The image display unit 174 includes a control unit 175, an intermediate image forming unit 176, and a projection unit 177. The control unit 175 generates a control signal for controlling operations of the light source device 11 and the light deflection device 13 in order to form the intermediate image 40. In addition, the control unit 175 generates a control signal for controlling the operation of the free-form curved mirror 30 in order to display the virtual image 45 at a predetermined position.

  The intermediate image forming unit 176 forms the intermediate image 40 on the screen 15 based on the control signal generated by the control unit 175. The projection unit 177 projects the laser light constituting the intermediate image 40 onto a transmission / reflection member (the windshield 50 or the like) in order to form the virtual image 45 that is visually recognized by the observer 3.

  Next, a detailed functional configuration of the display brightness control unit 178 will be described. FIG. 13 is a diagram illustrating an example of a detailed functional configuration of the display brightness control unit according to the first embodiment. Display luminance control unit 178 includes luminance information acquisition unit 81, sampling cycle management unit 82, storage / readout unit 83, display luminance determination unit 84, and storage unit 800.

  The luminance information acquisition unit 81 has a function of acquiring luminance information 450 including luminance data detected by the luminance sensor 70 from the luminance sensor 70. The brightness data detected by the brightness sensor 70 is data indicating a brightness value (illuminance value) in the brightness detection area 300. The luminance information acquisition unit 81 is an example of an acquisition unit.

  The sampling cycle management unit 82 is a function that manages a sampling cycle in which luminance data is detected by the luminance sensor 70. The sampling period is preset as a design value. The sampling cycle is preferably shorter than the periodic noise cycle of the background luminance.

  The period of the periodic noise of the background luminance is, for example, a blinking period of a direction indicator (blinker) of an automobile. Further, the periodic noise period of the background luminance may be a blinking period of a light blinking on a shoulder belt, a driving period of an automobile wiper, or the like. The periodic noise is not limited to this, and may be a sudden change in luminance that occurs at a relatively short period detected by the luminance sensor 70. The brightness sensor 70 can detect a change in brightness that is undesirable for the observer 3 by sampling the brightness data at intervals shorter than the period of such periodic noise. The luminance information acquisition unit 81 acquires luminance information 450 including luminance data detected based on the set sampling period from the luminance sensor 70.

  The storage / reading unit 83 has a function of storing various data in the storage unit 800 or reading various data from the storage unit 800. The storage / reading unit 83 has a function of storing the luminance information 450 acquired by the luminance information acquisition unit 81 in the luminance information management table 400 of the storage unit 800. The storage / reading unit 83 is an example of a storage control unit. In addition, the storage unit 800 stores a luminance information management table 400. Details of the luminance information management table 400 will be described later.

  The display brightness determination unit 84 is a function that determines the display brightness of the display information output from the display device 10A. For example, the display luminance determining unit 84 determines display luminance information 500 indicating the display luminance of the display information (virtual image 45) based on the representative value of the luminance information 450 stored in the luminance information management table 400. The representative value of the luminance information 450 is a numerical value that serves as a scale indicating the characteristics and trends of the values of all the luminance information 450 stored in the luminance information management table 400. The representative value of the luminance information 450 is, for example, an average value or a median value of all the luminance information 450 stored in the luminance information management table 400. The display luminance determining unit 84 is an example of a determining unit.

Here, the details of the luminance information management table stored in the storage unit 800 will be described with reference to FIG. FIG. 14 is a diagram illustrating an example of a luminance information management table according to the first embodiment. The luminance information management table 400 is a buffer area having a fixed size for storing the luminance information 450 acquired by the luminance information acquisition unit 81. The luminance information management table 400 is an example of a storage area.

  The luminance information management table 400 stores the luminance information 450 acquired by the luminance information acquisition unit 81 along the acquired time series. In the luminance information management table 400 shown in FIG. 14, the storage / readout unit 83 stores the acquired luminance information 450 in order from the area of the sampling number (n) “1”.

  Since the luminance information management table 400 has a finite size, there is no free space when the sampling number (n) reaches the upper limit. For this reason, the storage / reading unit 83 deletes the oldest luminance information 450 when determining that there is no free space in the luminance information management table 400. That is, the storage / reading unit 83 deletes the luminance information 450 stored in the area of the sampling number (n) “1” in the luminance information management table 400 and stores it in the area after the sampling number (n) “2”. The sampling number (n) of the luminance information 450 is incremented by one.

  Then, the storage / reading unit 83 stores the newly acquired luminance information 450 in the last area of the sampling number (n). For example, when the upper limit of the sampling number (n) in the luminance information management table 400 is “4”. The storage / reading unit 83 stores the newly acquired luminance information 450 in the area of the sampling number (n) “4”.

14 illustrates an example in which the luminance information 450 includes the luminance value [cd / m ² ] in the luminance information management table 400, the luminance information 450 may include an illuminance value [mlx (millilux)]. . In this case, the display device 10A acquires the luminance information 450 including the illuminance value [mlx] (illuminance data) of the luminance detection region 300 detected by the luminance sensor 70, and the acquired luminance information 450 is stored in the luminance information management table 400. Remember.

Display Brightness Control Processing Next, display brightness control processing of display information (virtual image 45) in the display device 10A will be described with reference to FIG. FIG. 15 is a flowchart illustrating an example of display brightness control processing in the display device according to the first embodiment. FIG. 15 shows the case where the positional relationship between the luminance detection area 300 and the display background area 350 by the luminance sensor 70 is as shown in FIG. An example in the case where periodic noise of background luminance occurs in a certain area will be described. The display luminance control process shown in FIG. 15 may be started when periodic noise is detected in the display device 10A, or the display luminance is controlled by always sampling the luminance information 450. May be.

In step S101, the luminance information acquisition unit 81 of the display device 10A acquires the luminance information 450 from the luminance sensor 70 (an example of an acquisition step). Specifically, the luminance sensor 70 detects the luminance data in the luminance detection region 300 at a sampling cycle that is predetermined by the sampling cycle management unit 82. The brightness data is a brightness value [cd / m ² ] in the brightness detection area 300. The luminance data may be an illuminance value [mlx] in the luminance detection region 300. The luminance information acquisition unit 81 acquires luminance information 450 including luminance data detected by the luminance sensor 70 from the luminance sensor 70.

  In step S102, the storage / reading unit 83 of the display device 10A shifts the processing to step S104 when there is a free area in the luminance information management table 400. On the other hand, when there is no free area in the luminance information management table 400, the storage / reading unit 83 shifts the process to step S103.

  Since the luminance information management table 400 is a buffer area having a fixed size, when the stored luminance information 450 reaches the upper limit of the number of samplings, there is no empty area. Therefore, the display device 10 </ b> A needs to create a new area for storing the luminance information 450, and therefore determines whether there is an empty area in the luminance information management table 400. For example, when the upper limit of the number of samplings is four, the luminance information management table 400 shown in FIG. 14 stores the luminance information 450 up to the area of sampling number (n) “4”, so there is no free area. State.

  In step S103, the storage / reading unit 83 of the display device 10A deletes the oldest luminance information 450 stored in the luminance information management table 400. Specifically, the storage / reading unit 83 stores the empty area in the luminance information management table 400 and stores it in the area of the sampling number (n) “1” included in the luminance information management table 400 shown in FIG. The brightness information 450 is deleted. When the luminance information 450 is deleted from the luminance information management table 400, the storage / reading unit 83 shifts the processing to step S104.

  In step S104, the storage / reading unit 83 of the display device 10A stores the luminance information 450 acquired by the luminance information acquisition unit 81 in the luminance information management table 400 (an example of a storage control step). At this time, the new luminance information 450 is stored at the end of the luminance information management table 400 in order to clarify the time series of the acquired luminance information 450. For example, in the luminance information management table 400 shown in FIG. 14, when the luminance information 450 is stored up to the area of the sampling number (n) “3”, the storage / reading unit 83 stores the newly acquired luminance information 450. And stored in the area of sampling number (n) "4".

In step S105, the display luminance determining unit 84 of the display device 10A uses the luminance information 450 stored in the luminance information management table 400 to determine the display luminance information 500 indicating the display luminance of the display information (virtual image 45) ( An example of a determination step). Specifically, for example, the display luminance determination unit 84 calculates an average value of luminance values [cd / m ² ] included in the luminance information 450 stored in the luminance information management table 400, and displays the calculated average value. The luminance information 500 is determined. In addition, the display luminance determination unit 84 calculates, for example, a median value of luminance values [cd / m ² ] included in the luminance information 450 stored in the luminance information management table 400, and the calculated median value is displayed on the display luminance information 500. Determine as.

  Here, when the processing up to step S104 is performed, the display device 10A stores the number of samplings (buffer size) in the luminance information management table 400 in the sampling period of the luminance sensor 70 from the time when the luminance information 450 is acquired this time. ), The luminance information 450 up to the time that goes back by the amount of time multiplied by () is held. The display luminance determining unit 84 determines display luminance information 500 indicating the display luminance of the display information based on the representative values of all the luminance information 450 during the time.

When the luminance data detected by the luminance sensor 70 is an illuminance value [mlx], the display luminance determining unit 84 calculates a representative value of the illuminance value [mlx] included in the luminance information 450, and the calculated value is , And converted into a luminance value [cd / m ² ]. The conversion process from the illuminance value [mlx] to the luminance value [cd / m ² ] is performed, for example, by a method of adding a predetermined constant to the illuminance value [mlx] calculated as the representative value. When the luminance data detected by the luminance sensor 70 is the illuminance value [mlx], the display luminance determination unit 84 converts the illuminance value [mlx] included in the luminance information 450 into the luminance value [cd / m ² ]. After that, a representative value of the converted luminance value [cd / m ² ] may be calculated.

  In step S <b> 106, the display brightness determination unit 84 of the display device 10 </ b> A outputs the determined display brightness information 500 to the image generation unit 173. The image generation unit 173 reflects the display luminance value indicated by the display luminance information 500 on the display luminance of the display information (virtual image 45). And the image display part 174 displays display information using the display brightness | luminance which the display brightness information 50 shows (an example of a display step).

  In step S107, the display brightness control unit 178 of the display device 10A repeats the process from step S101 when the display brightness control is continued. On the other hand, when the display brightness control unit 178 does not continue the control of the display brightness, the process ends.

  As described above, the display device 10A controls the display brightness of the display information based on the representative value of the brightness information 450 acquired along the time series, so that the periodic noise of the background brightness that is not desirable for the observer 3 can be obtained. The influence can be reduced. Further, the display device 10A can suppress the delay until the acquired luminance information 450 is reflected in the display luminance by repeating the addition or deletion of the acquired luminance information 450 in time series, and the background luminance The influence of periodic noise can be reduced.

  Although FIG. 15 illustrates an example in which all the luminance information 450 stored in the luminance information management table 400 is used, the display luminance determining unit 84 uses only the luminance information 450 stored in a specific sampling number (n). You may make it the structure to use. FIG. 15 illustrates an example in which the average value of the luminance information 450 is calculated. However, the average value of the luminance information 450 is not limited to the average value of the luminance information 450. Further, the display luminance determining unit 84 may calculate a value obtained by adding a predetermined constant to the calculated average value or median value as the display luminance information 50.

Specific Example Here, a specific example of luminance periodic noise in the driver's field of view will be described with reference to FIG. The image shown in FIG. 16A is an image obtained by adding a luminance detection region 300 and a display background region 350 to a front landscape image (background image) taken using a drive recorder attached to a car. FIG. 16A shows a situation in which the front vehicle blinks the direction indicator 370.

  In the image shown in FIG. 16A, the luminance detection area 300 includes the direction indicator 370 of the preceding vehicle, but the display background area 350 does not include the direction indicator 370. In this case, there is no change in the background brightness in the display background area 350, but the display brightness determined based on the brightness data in the brightness detection area 300 may be affected by the blinking of the direction indicator 370.

FIG. 16B shows luminance data 600 detected in the luminance detection region 300 in the image state shown in FIG. 16A and processing data 650 obtained by performing display luminance control processing based on the luminance data 600. Show. In the graph of FIG. 16B, the vertical axis indicates the luminance value [cd / m ² ], which is the magnitude of the detected luminance, and the horizontal axis indicates the time when the luminance value is acquired.

  The processing data 650 shows that the influence of an undesirable periodic luminance change due to the direction indicator 370 entering the luminance detection region 300 is reduced with respect to the detected luminance data 600. This is because, in the display device 10A, as shown in FIG. 15, representative values of the plurality of luminance information 450 are calculated and the acquired luminance data 600 is smoothed.

  Here, in Japan, the direction indicator 370 of an automobile is required to blink at a constant cycle of 60 to 120 times per minute. Therefore, since the shortest interval of the blinking cycle of the direction indicator 370 is 500 msec, it is preferable that the display device 10A acquires the luminance information 450 (sets the sampling cycle) at a cycle shorter than this cycle.

  In FIG. 16, an example of periodic noise caused by the direction indicator of the automobile is shown. However, the display brightness control processing according to the present embodiment is performed by a cycle caused by a blinking lamp or the like installed in a road branch or roadside zone. It is also effective against static noise. In addition, the display brightness control process according to the present embodiment is also effective for the entry of light from a streetlight that is running at a constant speed. Furthermore, the display brightness control process according to the present embodiment is applicable not only to the night but also to the brightness change of the brightness detection region 300 caused by the shadow of the roadside tree in the daytime.

Effect of First Embodiment As described above, the display system 1A according to the first embodiment detects the luminance including at least a part of the display background region 350 that displays the display information (virtual image 45) in a superimposed manner. A change in display luminance that is unpleasant for the observer 3 following a periodic luminance change in a short period in the region 300 is suppressed. Therefore, the display system 1A can improve the visibility of the display information (virtual image 45).

● Modification of the first embodiment ●
Subsequently, a configuration of a modified example of the first embodiment will be described. The same configurations and functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The display system according to the modification according to the first embodiment is a system in which the positional relationship between the luminance detection region 300 and the display background region 350 by the luminance sensor 70 is different from that of the first embodiment.

  FIG. 17 is a diagram for explaining an example of the relationship between the luminance detection region and the display background region according to the modification of the first embodiment. In the first embodiment, as illustrated in FIG. 10, the luminance detection area 300 includes the display background area 350. However, the positional relationship between the luminance detection area 300 and the display background area 350 is not necessarily limited. It is not limited to this example.

  In the example shown in FIG. 17A, a part of the luminance detection area 301 and a part of the display background area 351 are superimposed. Similarly, in the example shown in FIG. 17B, a part of the luminance detection area 302 and a part of the display background area 352 are superimposed. In the example shown in FIG. 17B, the range of the luminance detection region 302 outside the display background region 352 is smaller than that in FIG. 17A compared to FIG. When the positional relationship shown in FIG. 17B is applied, the display device 10 </ b> A has a possibility of detecting periodic noise that does not contribute to the luminance change in the display background region 352 compared to the example of FIG. Can be reduced.

  In the example shown in FIG. 17C, the luminance detection area 303 is included in the display background area 353. When the positional relationship shown in FIG. 17C is applied to the display device 10A, the luminance data detected in the luminance detection region 303 indicates the luminance of the background luminance in the display background region 353. A change in the background luminance of the display background area 353 can be accurately reflected.

  The display system 1A can apply the display luminance control process shown in FIG. 15 in any case shown in FIGS. 17 (a) to 17 (c). 10 and 17 show an example in which at least a part of the luminance detection region and the display background region overlap, the luminance detection region and the display background region do not necessarily overlap.

● Second embodiment ●
Next, the configuration of the second embodiment will be described. The same configurations and functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. When the display system 1B according to the second embodiment detects periodic noise, the display system 1B does not determine the display luminance information 500 using all the luminance information 450 stored in the luminance information management table 400, but periodically Display luminance information 500 is determined in a state where luminance values corresponding to noise are thinned out.

  Here, in the usage scene shown in FIG. 16, the display background area 350 is an area where the direction indicator 370 does not exist. That is, the actual brightness of the display background area 350 is the brightness when the direction indicator 370 is turned off. However, in the case of the usage scene shown in FIG. 16, since the lighting light of the direction indicator 370 is included in the luminance detection area 300 for sampling the luminance data for determining the display luminance, the determined display luminance is the display background. It becomes higher than the actual brightness of the region 350.

  Therefore, the display device 10B according to the second embodiment sets the display brightness close to the actual brightness of the display background region 350 by setting the display brightness to a value lower than the average value of the brightness information 450. Can do.

  FIG. 18 is a flowchart illustrating an example of display brightness control processing in the display device according to the second embodiment. Note that the processing from step 201 to step S204 shown in FIG. 18 is the same as the processing from step S101 to step S104 shown in FIG.

  In step S205, when the display brightness determination unit 84 of the display device 10B determines that there is a periodic change in the brightness information 450 included in the brightness information management table 400, the process proceeds to step S206. The periodic change is, for example, a change in luminance (illuminance) based on the blinking cycle by the direction indicator 370 or a change in luminance (illuminance) based on the lighting interval of the roadside trees.

In step S206, the display luminance determining unit 84 of the display device 10B determines the display luminance information 500 using the luminance information 450 excluding the highest luminance value [cd / m ² ] stored in the luminance information management table 400. . For example, if the display luminance determination unit 84 determines that the luminance information 450 acquired by the luminance information acquisition unit 81 has a periodic change, the display luminance determination unit 84 sets the maximum value of the luminance value [cd / m ² ] in a certain sampling period. The average value is calculated by thinning out, and the calculated value is set as display luminance information 500. As in the first embodiment, the value included in the luminance information 450 may be an illuminance value [mlx]. In this case, the display luminance determining unit 84 determines the display luminance information 500 using the luminance information 450 excluding the largest illuminance value [mlx] stored in the luminance information management table 400.

In step S208, the display brightness determination unit 84 of the display device 10B outputs the calculated display brightness information 500 to the image generation unit 173. Then, the image generation unit 173 reflects the luminance value [cd / m ² ] included in the display luminance information 500 on the display luminance of the virtual image 45.

  In step S209, the display luminance control unit 178 of the display device 10B repeats the processing from step S201 when the display luminance control is continued. On the other hand, when the display brightness control unit 178 does not continue the control of the display brightness, the process ends.

  On the other hand, when the display brightness determination unit 84 of the display device 10B determines in step S205 that there is no periodic change in the brightness information 450 included in the brightness information management table 400, the process proceeds to step S207. When it is determined that the luminance information 450 has no periodic change, the display luminance determining unit 84 uses the representative values of all the luminance information 450 stored in the luminance information management table 400 as in the first embodiment. Thus, the display luminance information 500 is determined. The processing after step S207 is the same as the processing from step S105 to step S107 shown in FIG.

  In addition, although FIG. 18 demonstrated the example which determines the average value of the luminance information 450 after thinning out the luminance value resulting from a periodic noise as the display luminance information 500, the display luminance information 500 is not restricted to an average value. Any value that is lower than the simple average of the luminance information 450 stored in the luminance information management table 400 may be used. The display luminance determining unit 84 may determine, for example, the median value of the luminance information 450 after thinning out luminance values due to periodic noise as the display luminance information 500 or stored in the luminance information management table 400. A predetermined value (a constant value) corresponding to the value of the luminance information 450 may be determined as the display luminance information 500.

● Effect of the second embodiment ●
As described above, when the generation of the periodic noise is detected, the display system according to the second embodiment does not use the simple average of the luminance information 450 but displays a value lower than the simple average value as the display luminance information 500. As a result, it is possible to realize display with display luminance with reduced influence of periodic noise. In addition, when occurrence of periodic noise is not detected, display luminance information 500 is determined using a simple average of luminance information 450, so that display luminance control processing is performed regardless of the presence or absence of periodic noise. Can be carried out continuously.

● Summary ●
As described above, the display device according to the embodiment of the present invention is the display device 10 </ b> A that displays the virtual image 45 (an example of display information) in front of the moving body, and the display background region that is the background of the virtual image 45. The brightness information 450 indicating the brightness of the brightness detection area 300 (an example of the peripheral area) including at least a part of 350 (an example of the display area) is acquired, and the acquired brightness information 450 is stored in the brightness information management table 400 (an example of the storage area). ). Then, the display device 10A determines display luminance information 500 indicating the display luminance of the virtual image 45 based on the representative value of the stored luminance information 450, and displays the virtual image 45 using the determined display luminance information 500. . Therefore, the display device 10 </ b> A can improve the visibility of display information by suppressing a change in display luminance that is undesirable for the observer 3.

  In addition, the display device according to the embodiment of the present invention stores the luminance information 450 obtained from the luminance information management table 400 (an example of a storage area) in time series, and the luminance information management table 400 includes an empty area. If not, the oldest luminance information 450 is deleted. Therefore, the display device 10A can suppress a delay until the acquired luminance information 450 is reflected in the display luminance by repeating addition or deletion of the acquired luminance information 450 in time series. The influence of periodic noise on luminance can be reduced.

  Furthermore, the display device according to the embodiment of the present invention acquires luminance information 450 indicating the luminance of the luminance detection region 300 (an example of the peripheral region) that includes the display background region 350 (an example of the display region). Therefore, the display device 10 </ b> A can reflect the change in the background luminance of the display background region 350 on which the virtual image 45 (an example of display information) is superimposed without any omission in the display luminance of the virtual image 45.

  In addition, the display device according to the embodiment of the present invention includes the luminance information 450 at intervals shorter than the specific luminance change cycle or less than the specific luminance change cycle that occurs in the luminance detection region 300 (an example of the peripheral region). To get. Therefore, the display device 10A can further reduce the influence of the periodic noise on the display luminance by detecting the periodic noise of the background luminance that is undesirable for the observer 3.

  Furthermore, the display device according to the embodiment of the present invention has a specific brightness generated in the brightness detection area 300 (an example of the peripheral area) in the brightness information 450 stored in the brightness information management table 400 (an example of the storage area). When there is a change, the display luminance information 500 is determined based on the representative value excluding the luminance information 450 having the highest luminance among the luminance information 450 stored in the luminance information management table 400. Therefore, when the generation of periodic noise is detected, the display device 10B does not use a simple average of the luminance information 450, but determines a value lower than the simple average value as the display luminance information 500, thereby periodically It is possible to realize display with display luminance with reduced influence of noise.

  In addition, the display system according to the embodiment of the present invention two-dimensionally scans the screen 15 with light emitted from the screen 15 (an example of an optical element) that diverges light and the light source device 11 (an example of a light source). And a display device 10 </ b> A that displays a virtual image 45 formed by diverging light diverged from the screen 15. In addition, the display system 1A includes a luminance sensor 70 (an example of a detection device) that detects the luminance of the luminance detection region 300 (an example of a peripheral region), and a windshield 50 (a reflective member) that reflects the divergent light emitted from the screen 15. And a free-form surface mirror 30 (an example of an imaging optical system) that projects the diverging light emitted from the screen 15 toward the windshield 50 to form a virtual image 45. Therefore, the display system 1 </ b> A can improve the visibility of display information by suppressing a change in display luminance that is undesirable for the observer 3.

  In addition, the display luminance control method according to an embodiment of the present invention is a display luminance control method executed by the display device 10A that displays a virtual image 45 (an example of display information) in front of a moving object, and the background of the virtual image 45 An acquisition step of acquiring luminance information indicating the luminance of the luminance detection region 300 (an example of the peripheral region) including at least a part of the display background region 350 (an example of the display region), and the acquired luminance information 450 as the luminance information A storage control step to be stored in the management table 400 (an example of a storage area), and a determination step to determine display luminance information 500 indicating the display luminance of the virtual image 45 based on the representative value of the stored luminance information 450. The display step of displaying the virtual image 45 using the display luminance information 500 is executed. Therefore, the display brightness control method according to an embodiment of the present invention can improve the visibility of display information by suppressing a change in display brightness that is undesirable for the observer 3.

● Supplement ●
Although the display device, display system, moving body, display luminance control method, and program according to an embodiment of the present invention have been described, the present invention is not limited to the above-described embodiment, and those skilled in the art will understand. It can be changed within the range that can be conceived.

  In addition, the display device according to the embodiment of the present invention has been described as an example of a HUD device mounted on an automobile that is an example of a moving body. However, the display device according to the embodiment of the present invention is, for example, a head It may be a mount display device or the like. In this case, the display device according to the embodiment of the present invention applied to the head mounted display device displays the external world and the virtual image in a superimposed manner. Furthermore, the display device according to an embodiment of the present invention can also be applied to a device having a display method that allows a display surface to be transmitted so that an external scenery (background) can be seen, such as a see-through display.

  Furthermore, the function of each embodiment can be realized by a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark), an object-oriented programming language, or the like. The program for executing the function can be distributed through a telecommunication line.

  The programs for executing the functions of the embodiments are ROM, EEPROM (Electrically Erasable Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), flash memory, flexible disk, CD (Compact Disc)- Store and distribute in device-readable recording media such as ROM, CD-RW (Re-Writable), DVD-ROM, DVD-RAM, DVD-RW, Blu-ray Disc, SD card, MO (Magneto-Optical disc), etc. You can also.

  Furthermore, part or all of the functions of each embodiment can be mounted on a programmable device (PD) such as an FPGA (Field Programmable Gate Array), or can be mounted as an ASIC. Circuit configuration data (bitstream data) downloaded to the PD in order to realize the above functions on the PD, HDL (Hardware Description Language) for generating the circuit configuration data, VHDL (Very High Speed Integrated Circuits Hardware Description Language), It can be distributed on a recording medium as data described in Verilog-HDL or the like.

1, 1A, 1B Display system 10, 10A, 10B Display device 11 Light source device 13 Optical deflection device (an example of a scanning unit)
15 screen (example of optical element)
30 Free-form surface mirror (an example of an imaging optical system)
50 Windshield (an example of a reflective member)
70 Luminance sensor (an example of a detection device)
81 Luminance information acquisition unit (an example of acquisition means)
83 Storage / reading unit (an example of storage control means)
84. Display luminance determining unit (an example of determining means)
400 Luminance information management table (an example of a storage area)

JP 2008-1182 A

Claims (12)

A display device that displays display information in front of a moving body,
Obtaining means for obtaining luminance information indicating luminance of a peripheral area including at least a part of a display area serving as a background of the display information;
Storage control means for storing the acquired luminance information in a storage area;
Determining means for determining display luminance information indicating the display luminance of the display information based on a representative value of the stored luminance information;
A display device that displays the display information using the determined display luminance information. The storage area stores the acquired luminance information along a time series,
The display device according to claim 1, wherein the storage control unit deletes the oldest luminance information when there is no empty area in the storage area.   The display device according to claim 1, wherein the determining unit determines an average value of the stored luminance information as the display luminance information.   The display device according to claim 1, wherein the determining unit determines a median value of the stored luminance information as the display luminance information.   The display device according to claim 1, wherein the acquisition unit acquires luminance information indicating luminance of the peripheral region that includes the display region.   6. The display device according to claim 1, wherein the acquisition unit acquires the luminance information at an interval shorter than or less than a period of a specific luminance change occurring in the peripheral region. .   When the specific luminance change is present in the stored luminance information, the determination unit is configured to determine the representative value based on the representative value excluding the luminance information having the highest luminance among the stored luminance information. The display device according to claim 6, wherein display luminance information is determined. The display device according to claim 1, further comprising:
An optical element that emits light;
A scanning unit that two-dimensionally scans the optical element with light emitted from a light source,
A display device that displays a virtual image formed by divergent light diverged from the optical element. A display device according to claim 8;
A detection device for detecting the luminance of the peripheral area;
A reflecting member that reflects diverging light emitted from the optical element;
An imaging optical system that forms a virtual image by projecting diverging light emitted from the optical element toward the reflecting member;
A display system comprising: A display system according to claim 9,
The reflecting member is a moving body that is a windshield that reflects the diverging light. A display brightness control method executed by a display device that displays display information in front of a moving body,
An acquisition step of acquiring luminance information indicating the luminance of a peripheral region including at least a part of a display region serving as a background of the display information;
A storage control step of storing the acquired luminance information in a storage area;
A determination step of determining display luminance information indicating a display luminance of the display information based on a representative value of the stored luminance information;
A display step of displaying the display information using the determined display luminance information;
Display brightness control method to execute.   A program for causing a computer to execute the display luminance control method according to claim 11.