JP2012058690A - Display unit of head-up display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display unit of a head-up display capable of preventing an image as display light from being visually recognized as a ghost light by a driver, by regulating emission of the display light outside the range of a prescribed emission angle out of display light emitted from a back light through an indicator onto a windshield.SOLUTION: A display unit 20 of a head-up display enables an image made to be formed outside of a windshield by display light reflected on an inner surface of a windshield to be visually recognized by a driver in a vehicle compartment. A housing 21 of the display unit 20 has light shielding pieces 25 for obstructing propagation of light propagated to directions L3 different from a prescribed direction L1 out of light emitted from a lens array 24.

Description

  The present invention relates to a display device for a head-up display that reflects display light on the inner surface of a windshield and allows a driver to view the reflected light as an image formed outside the windshield.

  In recent years, along with the increase and diversification of information required by the driver during driving, information that cannot be displayed due to space in the meter unit is displayed on the windshield, and through the outside of the windshield A projection-type display unit called a head-up display (HUD) device that allows the user to see an image tied to the head is used (see, for example, Patent Document 1).

  The display device (display unit) used for the head-up display device has reached a certain luminance in a specific viewing angle region, which is indispensable for maintaining the quality of the display image (image), brightness and darkness unevenness, etc. is there. In addition, the display optical path from the display device to the projection area in the windshield, combiner, etc. differs depending on the type of vehicle, but the direction of the light beam emitted from the display device is also determined by the display device. And the mounting angle is also limited. For this reason, it is necessary to design a display device corresponding to each vehicle, and the head-up display device cannot be made common to a plurality of types of vehicles.

  On the other hand, a display unit for a vehicle that maintains display quality and can be mounted on a plurality of types of vehicles is provided (see, for example, Patent Document 2). As shown in FIG. 5, the vehicle display unit 10 includes a display 11 and a backlight 12 that is provided on the back side of the display 11 and emits light for causing the display 11 to emit light. An image obtained by projecting an emitted light beam from a backlight 12 mounted on a vehicle and transmitted through a display 11 onto a projection area of the vehicle, and a foreground of the vehicle that is visually recognized through the projection area from the eye point of the vehicle. It is the structure made to superimpose visually.

  The vehicle display unit 10 includes a light beam restricting member (Fresnel lens) 15 that is interposed between the display 11 and the backlight 12 and restricts the direction of light from the backlight 12 toward the display 11. In the vehicle, the light beam regulating member 15 is placed on the display device 11 so that the emitted light beam that has passed through the display device 11 is directed to a predetermined display light path from the vehicle display unit 10 to the projection area. And a directivity adjusting member 16 that adjusts the directivity of the emitted light beam. Reference numeral 13 denotes a lens array that emits light from the backlight 12 at a wide angle, reference numeral 14 denotes a diffusion plate that diffuses light that has passed through the light beam restricting member 15 toward the display 11, and reference numeral 12 a is provided with the backlight 12. Printed circuit board.

  Therefore, the light beam restricting member 15 that restricts the direction of the light from the backlight 12 toward the display device 11 is transmitted through the display device 11 in the display light path from the vehicle display unit 10 to the projection area of the vehicle. The directivity adjusting member 16 positions the light beam regulating member 15 between the display 11 and the backlight 12 so that the directivity of the emitted light beam is adjusted so that the emitted light beam is directed. Thereby, even if the display optical path to the projection area differs depending on the type of vehicle, it can be dealt with only by changing the directivity adjusting member 16, so that the directivity characteristic of the emitted light can be adjusted.

  Moreover, since the light beam regulating member 15 regulates the direction of light traveling from the backlight 12 toward the display device 11, the viewing angle range of the emitted light beam can be set to a predetermined region and high luminance can be maintained. Therefore, it is not necessary to newly design and manufacture the components of the backlight 12 according to the type of vehicle, and the display quality can be maintained and mounted on a plurality of types of vehicles. The unit 10 can be shared.

JP 2002-293162 A JP 2008-189021 A

The conventional display device (display unit) 10 described above has the following problems to be solved.
That is, when the same head-up display is mounted on a vehicle of a different vehicle type, the emission angle of the light beam from the backlight 12 can be adjusted (enlarged) by installing the directivity adjusting member 16, so that the driver ( Although a certain display brightness and an effect of eliminating unevenness in brightness and darkness can be obtained from the eye range), a part of the light that has passed through the directivity adjusting member 16 in the housing 10A is reflected by the inner surface of the side wall of the housing 10A. L2 is directly reflected on the display 11 from the backlight without being reflected by the inner surface of the side wall, and this light is reflected by the windshield after passing through the display 11 and reaches the driver. This reflected light reaching the driver is regarded as a ghost image (virtual image) that is formed outside the windshield.

  This will be described with reference to FIG. 6. In the housing 10A, the optical system K including the diffuser plate 14, the Fresnel lens 15, the lens array 13, and the directivity adjusting member 16, the backlight 12, and the display 11 are provided. The light L1 after being installed and receiving the light of the backlight 12 and subjected to the directivity adjustment by the directivity adjusting member 16 is emitted in a substantially vertical direction with respect to the display 11, whereas the directivity adjustment is insufficient. Or a part of the light L2 diffused after the orientation adjustment is reflected by the inner surface of the side wall of the housing 10A and passes through the display 11 in an oblique direction.

  Therefore, as shown in FIG. 7, the display light L1 emitted from the display device 11 in the substantially vertical direction is reflected by the inner surface of the windshield 17 and reaches the driver, and an image of the display light is displayed on the windshield 17. It can be viewed as an image formed outward. On the other hand, the light reflected on the inner surface of the side wall in the housing 10A is incident and reflected on another part of the inner surface of the windshield 17 and reaches the driver. The light beam L2 is a light beam having an emission angle shifted from the display light L1, and is regarded as a ghost (image) that does not completely overlap the display image (display information) that is the display light L1, and is shown in FIG. 8, for example. It becomes like this. As a result, the display information held by the display light is misread, and the driver has an inconvenience such as wrong operation. FIG. 8 shows the ghost lights (ghost images) G1 and G2 that are displaced from the normal display lights (display images) F1 and F2 of the vehicle speed display and the direction indication display (left turn instruction display) on the display 11. An example is shown.

  The present invention has been made in view of the above-described circumstances, and an object thereof is display light propagating out of a predetermined emission angle range out of display light emitted from a backlight through a display toward a windshield. By restricting the emission of the display light before it is emitted from the display device, the image based on the display light is prevented from being viewed by the driver as a ghost image. An object of the present invention is to provide a display device for a head-up display that can be grasped and ensure sufficient vehicle driving safety.

In order to achieve the above-mentioned object, a display device for a head-up display according to the present invention is characterized by the following (1) to (4).
(1) Backlight,
A lens array that collects light emitted from the backlight and emits light in a predetermined direction;
A display that receives the light emitted from the lens array and emits the display light toward the inner surface of the windshield;
A housing that houses the backlight, the lens array, and the display;
With
A display device for a head-up display that enables a driver in a vehicle compartment to view an image formed on the outside of the windshield by display light reflected from the inner surface of the windshield,
The housing includes a member that prevents propagation of light emitted from the lens array in a direction different from the predetermined direction.
thing.
(2) A head-up display device configured as described in (1) above,
Shading treatment means is applied to the inner surface of the housing.
(3) A head-up display device configured as described in (2) above,
The shading processing means is a coating layer of a matte black paint.
(4) A head-up display device configured as described in (2) above,
The light shielding means is a light shielding plate protruding on the inner surface of the housing.

According to the configuration of (1) above, the light beams other than the display light that directly passes through the display device through the optical system among the light beams emitted from the backlight are attenuated, absorbed, or scattered by the member of the housing, and displayed. The light energy passing through the vessel is suppressed to a slight level. Therefore, only the display light that directly passes through the display unit among the light beams emitted from the backlight can be emitted toward the inner surface of the windshield, and the image based on the display light reflected on the inner surface of the windshield. Only the driver can be clearly observed. As a result, it is possible to prevent misreading of display information (direction instruction, vehicle speed, etc.) possessed by the display light, and to secure the expected driving safety.
According to the configuration of (2) above, the reflected light other than the light traveling straight from the backlight toward the display is absorbed by the light shielding processing unit, so that the direct display of the light emitted from the backlight is Only the display light passing therethrough can be emitted toward the normal position on the inner surface of the windshield, and only the image of the display light based on the emitted light can be seen by the driver.
According to the configuration of (3) above, the reflected light beam other than the light beam that has traveled straight through the optical path on the surface of the black paint is obtained by using a matte black paint around the optical path of the light having display information that needs to be viewed. By absorbing the light, it is possible to emit only the display light directly passing through the display unit toward the inner surface of the windshield out of the light emitted from the backlight easily and at low cost, and the image based on the emitted light. Only the driver can be seen.
According to the configuration of (4) above, the light shielding plate reflects light rays other than the display light directly emitted to the display unit out of the light rays emitted from the backlight. Further, it is attenuated by secondary reflection in the housing, or attenuated by repeating third and subsequent reflections one after another. Accordingly, only the display light that directly passes through the display unit among the light beams emitted from the backlight can be emitted toward the inner surface of the windshield, and the driver can view only the image based on the emitted light. be able to.

  According to the present invention, the display light emitted from the backlight as the light source to the windshield through the display unit is controlled by emitting display light outside the predetermined emission angle range emitted from the backlight. Thus, it is possible to avoid viewing the regulated display light as ghost light by a person, thereby clearly viewing an image based on the display light, and ensuring the safety of driving the vehicle.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a longitudinal cross-sectional view which shows the display apparatus of the head-up display concerning embodiment of this invention. It is sectional drawing which expands and shows the side wall of the housing shown in FIG. (A), (b) is explanatory drawing which shows the cut surface of a light shielding piece. It is explanatory drawing which shows the image of the display light observed using the head-up display of FIG. It is a longitudinal cross-sectional view which shows the display apparatus of the conventional head-up display. It is a longitudinal cross-sectional view of the display apparatus used for description of the conventional head-up display display operation. It is a conceptual diagram which shows the whole conventional head-up display. It is explanatory drawing which shows the ghost image seen in FIG.

  A display device for a head-up display according to an embodiment of the present invention will be described below with reference to FIGS.

  A display device 20 of a head-up display according to the present embodiment shown in FIG. 1 includes a housing 21, a backlight 22, a display device 23, and a lens array 24. This display device 20 is installed on the dashboard (not shown) inside the windshield of the vehicle. The display device 20 is formed into a rectangular cylindrical body using, for example, a black or black synthetic resin material. This black synthetic resin material has a function as a light absorbing material. The housing 21 is not limited to a synthetic resin and may be made of metal or wood. In this case, a matte black paint or the like is applied to the inner side wall.

  One or a plurality of pleated light-shielding pieces 25 are provided in a horizontal direction toward the center of the housing 21 on the inner side wall of the housing 21 and above the lens array installation portion described later. Yes. The length of the light shielding piece 25 protruding from the inner side wall of the housing 21 does not prevent the display light L1 from being emitted directly from the backlight 22 through the lens array 24 and the display 23 to the upper side of the housing 21. The length is such that light L3 that passes through the lens array 24 and propagates through an optical path different from the display light L1 is reflected downward toward the lens array 24 side.

  The front end portion of the light shielding piece 25 has a cut surface 25a as shown in FIG. 2, which is scraped off at an oblique angle, for example, 45 degrees. The cut surface 25a may be provided over the entire width of the light shielding piece 25 (the entire length in the horizontal direction), and the cut angle may be an acute angle or an obtuse angle other than 45 degrees.

  The backlight 22 uses one or a plurality of various light sources such as a light emitting diode (LED) and a fluorescent tube, and is mounted on a circuit board 26 having a driving circuit for lighting. The circuit board 26 is a bottom plate that closes the lower end of the cylindrical housing 21.

  The indicator 23 is horizontally held by a protruding edge 21 a formed on the inner surface of the opening at the upper end of the housing 21. The display 23 is a thin display device such as a liquid crystal display (LCD) or an EL display. The display 23 displays various information necessary for vehicle travel, such as vehicle speed during actual travel, engine speed, and direction indication display.

  The lens array 24 is an optical element in which a plurality of substantially hemispherical lenses are arranged side by side, and the convex portions of these lenses protrude toward the display 23 side, and the opposite side plane is provided to face the backlight 22. It has been. The lens array 24 condenses the light emitted from the backlight 22 and emits the light toward the display 23 in a predetermined direction, that is, the direction in which the light L1 propagates. Here, the lens array 24 is sandwiched between a pair of upper and lower mounting pieces 27, 27 protruding from the inner surface of the side wall of the housing 21. In FIG. 1, reference numeral 28 denotes an attachment piece protruding from the inner surface of the side wall of the housing 21 and protruding to attach the circuit board 26 to the housing 21 with screws or the like.

  The display device of the head-up display having such a configuration operates as follows. As described above, the housing 21 constituting the display device 20 is installed on the dashboard of the vehicle, and the backlight 22 at the bottom of the housing 21 is turned on so that the display device receives the lighting light. The image information of the display light displayed on 23 is projected onto the windshield 17. The display light reflected by the windshield 17 is incident on the driver in the passenger compartment.

  In this case, the light emitted from the backlight 22 is collected by a large number of hemispherical lenses in the lens array 24 before reaching the display 23, and is emitted toward the display 23. Of the light emitted from the lens array 24, the display light L 1 that directly enters the display 23 passes through a region (optical path) surrounded by the protruding edge 21 a of the housing 21 and is emitted toward the windshield 17. Then, the driver can observe an image formed on the outside of the windshield 17 based on the display light.

  On the other hand, of the display light emitted from the backlight 22 and passing through the lens array 24, the light rays that are not directly incident on the display 23 and are directed to the inner side wall of the housing 21 are black because the side wall is black. Since 21 itself is a light absorber made of a black synthetic resin material, light energy is absorbed and greatly attenuated, that is, the amount of light is drastically reduced. For this reason, the light incident on the inner side wall of the housing 21 hardly reaches the display 23 or does not enter the windshield 17 even if it reaches the display 23. Thus, the incident level of the light whose light energy is attenuated to the display 23 becomes small, and the light hardly reaches the windshield 17, so that a virtual image (ghost image) due to the display light having a low incident level is formed. It is not formed and the driver will not see it.

  Further, the light shielding piece 25 projecting from the inner side wall of the housing 21 reflects the light L3 that passes through the lens array 24 toward the inner surface of the side wall of the housing 21 downward as shown in FIG. reflect. For this reason, the primary reflected light is secondarily reflected downward on the inner surface of the side wall. For this reason, in addition to the housing 21 itself being black (light absorbing member) that hardly causes light reflection as described above, the light is directed downward (in the direction of the backlight 22) by primary, secondary,... The energy level of the light in the upper region of the lens array 24 becomes zero or close to zero. Therefore, it is possible to more reliably avoid the ghost image as described above.

  Further, the light shielding piece 25 has a cut surface 25a directed obliquely downward. When the cut surface is a vertical surface 25b as shown in FIG. 3B, a part of the light passing through the lens array 24 is reflected upward by hitting the vertical surface 25b. Tries to pass through the display 23 at a predetermined angle. In this case, since the reflected light reaches the inner surface of the windshield via the display 23, it is not preferable as described above. However, in this embodiment, since the cut surface 25a is directed obliquely downward, the display light directed toward the inner surface of the side wall of the housing 21 out of the light passing through the lens array 24 is obliquely downward as shown in FIG. By reflecting the display light, it is possible to reliably avoid the display light from being transmitted through the display unit 23. As a result, it is possible to more reliably avoid viewing the ghost image as described above.

  As described above, in this embodiment, the light reflected by the inner side wall of the housing 21 is not incident on the windshield 17 through the display unit 23, and therefore, it is possible to avoid viewing the ghost image by the driver. Can do. In the above-described embodiment, the housing 21 itself is formed of black synthetic resin. However, when the housing 21 is formed of, for example, white synthetic resin other than black, a matte black paint is evaporated or deposited on the inner side wall. By applying, light energy can be attenuated by light absorption. Further, the light energy generated by the light absorption function can be obtained by forming a fine protrusion structure in which a large number of fine protrusions are provided on the inner side wall of the housing 21, performing a flocking coating process, or attaching a sheet with flocking. Can be realized.

  As described above, according to the display device of the head-up display according to the present embodiment, among the light beams emitted from the backlight 22, light beams other than the display light directly incident on the display device 23 via the lens array 24 are The light is absorbed without being reflected by the inner side wall of the housing 21 made of a light absorbing member, or the reflection is suppressed, and the light energy passing through the display 23 is also reduced. Therefore, only the display light that directly passes through the display unit 23 through the lens array 24 among the light beams emitted from the backlight 22 can be emitted toward the inner surface of the windshield 17, and an image based on this emission light can be emitted. Only the driver can be seen. As a result, it is possible to prevent erroneous reading of display information included in the display light.

  Further, since the light shielding means is provided on the inner surface of the housing 21, the optical path of light having display information that mainly needs to be monitored, not the entire housing 21 that houses the backlight 22 and the display 23. Display light that directly passes through the display unit 23 out of the light emitted from the backlight 22 by absorbing the reflected light other than the light traveling straight in this optical path in the light shielding main stage. Can be emitted toward the inner surface of the windshield 17.

  Further, the light shielding treatment means is matted as a black paint coating layer, and the reflected light other than the light traveling straight in the optical path is absorbed by the black paint surface, so that the light emitted from the backlight 22 can be easily and low-cost. Only the display light that directly passes through the display 23 can be emitted toward the inner surface of the windshield 17.

  Further, the light shielding means is projected on the inner side wall of the housing 21 to shield light L3 having a propagation direction different from the light L1 propagating in a predetermined direction out of the light emitted from the backlight 22. By using a plurality of light shielding pieces 25, light reflected by the light shielding pieces 25 from the backlight 22 other than the display light directly emitted to the display unit 23 is reflected downward or obliquely downward. The light is further attenuated by the secondary reflection in the housing 21 or attenuated by repeating the third and subsequent reflections one after another. Accordingly, only the display light that directly passes through the display unit 23 via the lens array 24 among the light beams emitted from the backlight 22 can be emitted toward the inner surface of the windshield 17, and the above-described light emission based on the emission light can be emitted. Only the image can be seen by the driver.

  The light shielding means is provided on the inner side wall of the housing 21 and absorbs light L3 having a propagation direction different from the light L1 propagating in a predetermined direction out of the light emitted from the backlight 22. It is supposed to be flocked. Since the flocked portion is around the optical path of the light having display information that needs to be viewed, reflected light other than the optical path that travels straight through the optical path can be effectively and inexpensively absorbed by the flocked portion.

DESCRIPTION OF SYMBOLS 20 Display apparatus 21 Housing 22 Backlight 23 Display 24 Lens array 25 Light-shielding piece 26 Circuit board 27, 28 Attaching piece

Claims (4)

With backlight,
A lens array that collects light emitted from the backlight and emits light in a predetermined direction;
A display that receives the light emitted from the lens array and emits the display light toward the inner surface of the windshield;
A housing that houses the backlight, the lens array, and the display;
With
A display device for a head-up display that enables a driver in a vehicle compartment to view an image formed on the outside of the windshield by display light reflected from the inner surface of the windshield,
The housing includes a member that prevents propagation of light emitted from the lens array in a direction different from the predetermined direction.
A display device for a head-up display.   The display device for a head-up display according to claim 1, wherein a light shielding unit is provided on an inner side wall of the housing.   The display device for a head-up display according to claim 2, wherein the light-shielding processing means is a coating layer of a matte black paint.   The display device for a head-up display according to claim 2, wherein the light-shielding processing means is a light-shielding plate protruding on the inner side wall of the housing.

Images