JP2010064633A - Head-up display device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head-up display device for a vehicle, capable of preventing a user of the vehicle from recognizing an erroneous display image. <P>SOLUTION: The head-up display device irradiates the displayed light emitted from a plurality of pixels (liquid crystal display device 23) during light emission of a light source 22 into a windshield 13 and makes the user 14 recognize a display image V obtained by the light irradiation. The display unit includes control means 53 for controlling a driving voltage applied to each of the plurality of pixels based on a predetermined input signal, and a device drive circuit 54 in which a command signal from the control means 53 is input and which applies the driving voltage corresponding to the command signal to each of the plurality of pixels. The device drive circuit 54 includes a pixel state determination function which determines whether all pixel driving signals are in proper states when the all pixel driving signals are input as command signals and which outputs an abnormal-state signal into the control means 53 under an abnormal state. The control means 53 controls the light source 22 to execute turning-off operation when an abnormal-state signal is received. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle head-up display device that irradiates a projection member with display light emitted from a display element as light is emitted from a light source, and causes a vehicle user to visually recognize a display image (virtual image) obtained by the irradiation. It is.

  2. Description of the Related Art Conventionally, in this type of vehicle head-up display device, as described in Patent Document 1, for example, a display unit (display device) disposed inside an instrument panel (hereinafter referred to as instrument panel) of a vehicle. ) Is reflected on the windshield of the vehicle, which is a projection member, in the direction of the vehicle user (driver) to display a virtual image.

  Specifically, the vehicle head-up display device mounts a liquid crystal display element (display element) having a plurality of pixels arranged in a matrix, a light source located behind the liquid crystal display element, and the light source. The display unit is mainly composed of a circuit board, and display light (virtual image) obtained by irradiating (projecting) display light emitted from the liquid crystal display element to the windshield (projection member) when the light source emits light. ) Is visually recognized by the vehicle user. Thus, the vehicle user can observe a display image (for example, a display image including a vehicle speed display and a gear position display) displayed in front of the driver's seat in a superimposed manner with the scenery.

  In this case, the display unit includes a wiring board which is another circuit board different from the circuit board, and the wiring board includes, for example, an element driving circuit (driving unit) for driving a liquid crystal display element, Various circuit components such as a light source control circuit for controlling light emission of a light source, a microcomputer (control means), a resistor, and a capacitor are mounted.

For the electrical connection between the wiring board and the liquid crystal display element, a flexible wiring board (FPC) having a signal transmission line including a power line, a signal line, and a ground line is used. In this FPC, one end side of the FPC on the wiring board side is mounted inside an FPC connector mounted on the wiring board, whereby a signal transmission line located on one end side of the FPC is provided inside the connector. Each is electrically connected to a plurality of electrode terminals.
JP 2003-25871 A

  By the way, the above-described vehicle head-up display device (particularly the display unit) may be used in a harsh environment such as −40 degrees to 100 degrees. For the purpose of protection, the resin outer case provided in the connector is thermally deformed, and thus, for example, a part of the signal transmission line located on one end side of the FPC may not be electrically connected to the electrode terminal.

  As a result, the FPC and the wiring board are disconnected (in other words, a part of the signal transmission line is not connected to the electrode terminal of the connector), so that some of the plurality of pixels The drive voltage output from the element drive circuit via the signal transmission line is not applied to these pixels.

And when displaying a vehicle speed display, a gear position display, etc. on a liquid crystal display element, it originates in the said drive voltage not being applied to a part of these pixels (that is, disconnection of the said signal transmission line and a connector). For example, a part of display light (in this case, vehicle speed display light or gear position display light) emitted from the liquid crystal display element due to light emission of the light source is irradiated on the windshield in a state having a display defect, thereby There is a possibility that the user may visually recognize an incorrect display image (an incorrect vehicle speed display image, a gear position display image) due to the display defect, and there is room for further improvement in this respect.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle head-up display device that does not cause a vehicle user to visually recognize an erroneous display image in order to cope with the above-described problems.

  The present invention includes a display element having a plurality of pixels arranged in a matrix, and a light source located behind the display element, and projects display light emitted from the display element as the light source emits light. Control means for controlling a driving voltage applied to the pixel based on a predetermined input signal in a vehicle head-up display device for irradiating a member and allowing a vehicle user to visually recognize a display image obtained by the irradiation; A command signal from the control means, and a drive means for applying the drive voltage in accordance with the command signal to the pixels. The drive means receives all the pixel drive signals for driving all the pixels. When input as a command signal, it is determined whether or not the all-pixel drive signal is in a normal state, and if it is in an abnormal state, an abnormal state signal is output to the control means, Receives the abnormal condition signal, and performs control for turning off operation of the light source.

  ADVANTAGE OF THE INVENTION According to this invention, the initial objective can be achieved and the vehicle head-up display apparatus which does not have a possibility of making a vehicle user visually recognize a wrong display image can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 to 4 show an embodiment of the present invention, FIG. 1 is a schematic diagram of a vehicle head-up display device according to an embodiment of the present invention, and FIG. 2 is a vehicle head-up according to the embodiment. 3 is a cross-sectional view of the display device, FIG. 3 is a cross-sectional view of the display element according to the embodiment, and FIG. 4 is a block diagram illustrating an electrical configuration of the vehicle head-up display device according to the embodiment.

  As shown in FIG. 1, the vehicle head-up display device uses the windshield 13 of the vehicle 10, which is a projection member, to display light L projected by the display device 12 that is a display unit disposed inside the instrument panel 11 of the vehicle 10. The virtual image V is displayed by reflecting in the direction of the user (driver) 14 of the vehicle 10. In other words, the vehicle head-up display device irradiates (projects) the front glass 13 (the projection member) with the display light L emitted from a display device (to be described later) of the display device 12, and a display image obtained by the irradiation. (Virtual image) The user 14 is made to visually recognize V. Thereby, the user 14 can observe the virtual image V displayed in front of the driver's seat in a superimposed manner with the scenery.

  As shown in FIG. 2, the display device 12 mainly includes a display device 20, a reflector 30, and a housing 40.

  The display 20 includes a circuit board 21, a light source 22 mounted on the circuit board 21, and a liquid crystal display element (display element) 23 that transmits illumination light from the light source 22 and forms display light L. It becomes.

  The circuit board 21 is a hard circuit board on which a predetermined circuit pattern is applied, and a light source 22 is mounted on the circuit pattern.

  The light source 22 is composed of, for example, a chip-type light emitting diode, is located behind the liquid crystal display element 23, and is a light emitter that supplies illumination light to the liquid crystal display element 23.

  The liquid crystal display element 23 includes a known dot matrix type liquid crystal panel having a plurality of pixels arranged in a matrix, and a pair of glass substrates 24 and 25 and a space between these glass substrates 24 and 25 as shown in FIG. Liquid crystal molecules 26, a pair of transparent electrodes 27 and 28 formed on the inner surfaces of the glass substrates 24 and 25, and a color filter 29 attached to the surface of the glass substrate 24, respectively. . In the liquid crystal display element 23, polarizing plates are provided on the front surface of the glass substrate 24 (color filter 29) and the back surface of the glass substrate 25, but these are not shown.

  The transparent electrodes 27 and 28 are composed of a plurality of parallel stripe electrodes in units of the transparent electrodes 27 and 28, and the matrix electrodes (the plurality of pixels) intersecting in the vertical direction by combining the glass substrates 24 and 25. The liquid crystal molecules 26 corresponding to the pixel region sandwiched between the transparent electrodes 27 and 28 are driven by applying a selective voltage (drive voltage) between the transparent electrodes 27 and 28, and the pixel region It switches between transmission and non-transmission states and displays various information such as vehicle speed display and gear position display.

  The color filter 29 is provided with minute colored portions of R (red), G (green), and B (blue) corresponding to each pixel. Accordingly, the various information can be displayed in full color, and the liquid crystal display element 23 emits the various information as display light L as the light source 22 emits light.

  The reflector 30 includes a concave mirror (reflecting member) 31, a holding member 32, and a stepping motor 33. The concave mirror 31 is formed by depositing a metal (for example, aluminum) on a resin (for example, polycarbonate) to form a reflective surface 31a. The reflective surface 31a is a concave surface, and the display light L emitted from the display device 20 (that is, the display light L emitted from the liquid crystal display element 23 as the light source 22 emits light) is enlarged to display the virtual image V. The concave mirror 31 is bonded to the holding member 32 with a double-sided adhesive tape. The holding member 32 is made of resin (for example, ABS), and the gear portion 34 and the shaft portion 35 are integrally formed. The shaft portion 35 of the holding member 32 is pivotally supported by the housing 40.

  A gear 36 is attached to the rotation shaft of the stepping motor 33, and the gear 36 is engaged with the gear portion 34 of the holding member 32. The concave mirror 31 is supported so as to be rotatable together with the holding member 32, and the projection direction of the display light L can be adjusted by rotating the concave mirror 31 by the stepping motor 33.

  The housing 40 is made of, for example, a black light-shielding synthetic resin material, and is formed in a substantially box shape. The housing 40 holds and holds the display 20 and the reflector 30 in a space 41 that is an internal space thereof. An opening window portion 42 is provided in which an upper portion (front glass 13 side) of the arrangement position of the concave mirror 31 in the container 30 is opened.

  Further, the housing 40 is provided with a translucent cover 43 that is an emission part so as to close the opening window 42. The translucent cover 43 is made of a translucent synthetic resin material (for example, acrylic resin), is formed in a curved shape (curved surface shape), and transmits light that transmits (passes) the display light L reflected by the concave mirror 31. It has a function as a sex member. In other words, the display light L reflected by the concave mirror 31 is projected onto the windshield 13 through the translucent cover 43 formed on the housing 40, whereby the virtual image V is displayed to the user 14.

  Reference numeral 44 denotes a light shielding wall for preventing a phenomenon (washout) in which external light such as sunlight enters the display 20 and the virtual image V becomes difficult to see. The light shielding wall 44 has a flat plate shape. And is formed so as to hang obliquely from the top of the housing 40.

  In FIG. 2, F is a wiring board, G is a flexible wiring board, H is a connector, and J is a covering member. The wiring board F is made of, for example, a hard wiring board provided with a predetermined wiring pattern, is accommodated in the space 41 of the housing 40, and is appropriately fixed to the housing 40 by fixing means. The wiring board F includes a connector H, an element driving circuit to be described later for driving the liquid crystal display element 23, a light source driving circuit to be described later for controlling light emission of the light source 22, a motor driving circuit to be described later for driving the stepping motor 33, and a control to be described later. Means are mounted.

  The flexible wiring board G is used for electrical connection between the liquid crystal display element 23 and the wiring board F, and includes a signal transmission line (not shown) including a power line, a signal line, and a ground line. .

  In such a flexible wiring board G, one end side of the flexible wiring board G on the wiring board F side is mounted inside the connector H, whereby a signal transmission line located on one end side of the flexible wiring board G is placed inside the connector H. Each of the plurality of electrode terminals (not shown) provided is electrically connected. Here, the said electrode terminal shall be the structure protected by the resin-made exterior case with which the connector H is equipped.

  The covering member J is made of, for example, a black synthetic resin material, and is positioned on the upper side of the circuit board F so as to cover the circuit board F. In this example, the lower end portion of the concave mirror 31 and the liquid crystal display element 23 in FIG. It is arrange | positioned between the lower end parts of. Like the wiring board F, the covering member J is accommodated in the space 41 of the housing 40 and is fixed to the housing 40 by appropriate fixing means.

  Next, the electrical configuration of the vehicle head-up display device in this embodiment will be described with reference to FIG. In FIG. 4, 51 is a vehicle speed sensor, 52 is a gear position sensor, 53 is control means, 54 is an element drive circuit (drive means), 55 is a light source drive circuit, 56 is a motor drive circuit, 23 is a liquid crystal display element, 22 Is a light source, and 33 is a stepping motor.

  The vehicle speed sensor 51 outputs a pulse signal proportional to the vehicle speed.

  The gear position sensor 52 detects the gear position of the vehicle. In this example, the gear position is assumed to be operated in the “P” range. The operation position information from the gear position sensor 52 is input to the control means 53.

  The control means 53 is composed of a ROM having a processing operation program stored therein, a RAM for temporarily storing calculation values, a microcomputer having a CPU for executing the program, and the like, and is mounted on the wiring board F. In this example, it is assumed that the control means 53 is composed of a microcomputer with a built-in graphic controller.

  The control means 53 operates in response to the turning on of the power for starting the vehicle head-up display device, and is based on an input signal composed of a pulse signal from the vehicle speed sensor 51 and operation position information from the gear position sensor 52. A command signal (control signal) for controlling operations of the liquid crystal display element 23, the light source 22, and the stepping motor 33 is output.

  The control signal output from the control means 53 is input to individual drivers (drive circuit) corresponding to the liquid crystal display element 23, the light source 22, and the stepping motor 33. These drivers are connected to the liquid crystal display element according to the signal input. 23, the light source 22, and the stepping motor 33 are operated.

  Here, the control means 53 first drives the stepping motor 33 among the liquid crystal display element 23, the light source 22, and the stepping motor 33. That is, the control means 53 outputs a drive control signal for driving and controlling the stepping motor 33 in order to rotate the concave mirror 31 from the initial setting position to the predetermined setting position, and the motor drive circuit that has received this drive control signal. 56 outputs a signal for driving the stepping motor 33, whereby the stepping motor 33 is driven.

  Then, the rotation shaft of the stepping motor 33 is rotationally driven by the driving of the stepping motor 33, and the rotational driving force is transmitted through the gear 36 attached to the rotation shaft and the gear portion 34 of the holding member 32 that meshes with the gear 36. It is transmitted to the holding member 32, and the holding member 32 rotates about the rotation axis R. Thereby, the angular position of the concave mirror 31 is adjusted to be the predetermined set position. Here, the initial setting position is a position where the inclination angle θ formed by the bottom surface of the holding member 32 and the virtual horizontal line Y is approximately 10 degrees in FIG. 3, and the predetermined setting position is the inclination angle θ is substantially the same. The position is 45 degrees.

  The control means 53 is an element drive that is a drive means for controlling the drive voltage applied to each of the plurality of pixels based on the input signal after the angular position of the concave mirror 31 is adjusted to the predetermined set position. When the command signal is output to the circuit 54 and the command signal from the control means 53 (the graphic controller) is input, the element driving circuit 54 responds to the command signal to the liquid crystal display element 23 (the plurality of pixels). A drive voltage is applied, whereby various information is displayed on the liquid crystal display element 23. Here, in this example, it is assumed that the vehicle speed information is displayed in the central region of the liquid crystal display element 23 and the gear position information “P” is displayed in another region different from the central region.

  After the vehicle speed and gear position are displayed on the liquid crystal display element 23, the control unit 53 outputs a lighting control signal for lighting the light source 22 to the light source driving circuit 55, and receives the lighting control signal to receive the lighting control signal. 55 turns on the light source 22, whereby the display light L is emitted from the liquid crystal display element 23.

  After the display light L is emitted from the liquid crystal display element 23, it is irradiated to the windshield 13 through the concave mirror 31 whose inclination angle θ is set to about 45 degrees, and a display image (virtual image) obtained by this irradiation. V can be visually recognized by the user 14. The display image V is formed with a vehicle speed display image and a gear position display image in the normal display mode.

  In the present embodiment, the element drive circuit 54 drives all of the plurality of pixels before the user 14 visually recognizes the normal display mode as the display image V (for example, all the plurality of pixels are displayed). When an all-pixel drive signal is input as the command signal from the control means 53 (the graphic controller) to display white, it is determined whether or not the all-pixel drive signal is in a normal state, and is not in a normal state ( In the abnormal state), an abnormal state signal is output to the control means 53.

  Specifically, the operation of the control means 53 at this time will be described in detail. The control means 53 (the graphic controller) moves the concave mirror 31 to the predetermined setting position by driving control of the stepping motor 33 from the time of turning on the power. In order to display and drive all the plurality of pixels in white (mixed color of R pixel, G pixel, and B pixel) using the period until the position is adjusted, the element driving circuit 54 drives all pixels as the command signal. A signal is output.

  Then, in response to this all-pixel drive signal, the element drive circuit 54 applies a drive voltage corresponding to the command signal to each of the plurality of pixels, and if the plurality of pixels are all in a normal state, the liquid crystal display element 23. The plurality of pixels are all displayed in white.

  However, since the display device 12 described above is installed inside the instrument panel 11 of the vehicle 10, the exterior case of the connector H mounted on the wiring board F is thermally deformed particularly in a high temperature environment. As a result, a part of the signal transmission line of the flexible wiring board G may not be electrically connected to the electrode terminal located in the outer case.

  This means that the flexible wiring board G (part of the signal transmission line) is disconnected from the connector H (wiring board F). In this case, the element driving circuit 54 is It is determined (recognized) that there is abnormal data in a part of the data of the signal (all pixel drive signal) sent from the control means 53 (the graphic controller). In other words, in the disconnected state, the element drive circuit 54 is based on the input of all pixel drive signals, and all of the plurality of pixels are not in a normal state (in this case, white display) and some of the pixels are in an abnormal state (for example, It is determined (recognized) that the display is black. At this time, since it is assumed that a display defect is formed in a part of the display content of the display image V in the normal display mode, the element driving circuit 54 is one of the plurality of pixels as described above. When it is determined (recognized) that the pixels in the unit are in an abnormal state, an abnormal state signal indicating that the pixel is in an abnormal state is output to the control means 53.

  Upon receiving the abnormal state signal, the control means 53 outputs a light-off control signal to the light source drive circuit 55 to turn off the light source 22, and the light source drive circuit 55 turns off the light source 22 in response to the light-off control signal. To control. Therefore, when the pixel is in an abnormal state, the display light L is not emitted from the liquid crystal display element 23 (in other words, the display contents of the display image V in the normal display mode are not visually recognized by the user 14). Therefore, there is no possibility that the user 14 visually recognizes an erroneous display image V that is displayed and formed due to an abnormal state of the pixel (the display defect).

  As described above, in the present embodiment, the liquid crystal display element 23 having the plurality of pixels arranged in a matrix and the light source 22 located behind the liquid crystal display element 23 are provided. In the vehicle head-up display device that irradiates the front glass 13 with display light emitted from the liquid crystal display element 23 and causes the user 14 to visually recognize the display image V obtained by the irradiation, the plurality of the plurality of light sources are based on the input signal. A control unit 53 for controlling a driving voltage applied to each pixel; and an element driving circuit 54 for receiving a command signal from the control unit 53 and applying the driving voltage corresponding to the command signal to each of the plurality of pixels. When the all pixel drive signal is input as the command signal, the element drive circuit 54 determines whether or not all the pixel drive signals are in a normal state, and an abnormal state In some cases, the abnormal state signal is output to the control unit 53, and when the abnormal state signal is received, the control unit 53 performs a control to turn off the light source 22, for example, in a high temperature environment, the plurality of pixels. To provide a vehicle head-up display device that does not cause the user 14 to visually recognize an erroneous display image V caused by an abnormal state of a pixel even when some of the pixels are in an abnormal state. Can do.

  Further, in the present embodiment, the control unit 53 has been described as an example of performing control to turn off the light source 22 when the abnormal state signal is received from the element driving circuit 54. For example, the control unit 53 performs the abnormal state signal. On the basis of the above, the light source 22 may be turned off, and at the same time, a predetermined notification means for warning (notifying) that the vehicle head-up display device is not in a normal state may be operated.

  In this case, although the detailed illustration is omitted as the predetermined notification means, for example, a buzzer (sounding means) mounted on a meter board of a vehicle meter mounted on the vehicle 10 or provided in the vehicle meter. The indicator (light emission display part) etc. which were displayed can be employ | adopted. Moreover, it is also possible to employ both the buzzer and the indicator as the predetermined notification means.

  In the present embodiment, an example in which the display light L emitted from the display device 12 is projected onto the windshield 13 has been described. For example, a combiner film that reflects the display light L in the direction of the user 14 on the windshield 13 favorably. Alternatively, the display light L may be projected onto a dedicated reflector different from the windshield 13.

1 is a schematic view of a vehicle head-up display device according to an embodiment of the present invention. Sectional drawing of the head-up display apparatus for vehicles by the embodiment. Sectional drawing of the display element by the embodiment. The block diagram which shows the electrical constitution of the head-up display apparatus for vehicles by the embodiment.

Explanation of symbols

12 Display device 13 Windshield (projection member)
14 User 22 Light source 23 Liquid crystal display element (display element)
31 Concave mirror 33 Stepping motor 53 Control means 54 Element drive circuit (drive means)
55 Light source drive circuit 56 Motor drive circuit F Wiring board G Flexible wiring board H Connector V Display image (virtual image)

Claims (1)

A display element having a plurality of pixels arranged in a matrix, and a light source located behind the display element,
In a vehicle head-up display device that irradiates a projection member with display light emitted from the display element along with light emission of the light source, and causes a vehicle user to visually recognize a display image obtained by the irradiation.
Control means for controlling a driving voltage applied to the pixel based on a predetermined input signal;
A command signal from the control unit is input, and a drive unit that applies the drive voltage according to the command signal to the pixel is provided.
When an all-pixel drive signal for driving all of the pixels is input as the command signal, the drive unit determines whether or not the all-pixel drive signal is in a normal state, and the control is performed in a case of an abnormal state. Output an abnormal condition signal to the means,
When the control means receives the abnormal state signal, the control means performs control to turn off the light source.

Images