JP2019008090A - Head-up display device - Google Patents

Abstract

To provide a head-up display device that can improve visibility of a virtual image seen with naked eyes.SOLUTION: A head-up display device comprises: a display unit 30 that emits display light L; a concave mirror 51 that reflects the display light L; and a housing 60 that accommodates the display unit 30 and concave mirror 51. The head-up display device is provided, as the display unit 30, with a liquid crystal display 31 emitting the display light L and a hot mirror 32 arranged in front of the liquid crystal display 31 are provided, and projects the display light L reflected on the concave mirror 51 on a windshield 13 through a translucent part 65 formed in the housing 60 to display a virtual image to a driver 14. A high retardation film 35 is disposed in the middle of a light path of the display light L from the hot mirror 32 reaching the windshield 13.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a head-up display device that projects display light emitted from a display onto a projection member such as a windshield of a vehicle and displays a virtual image to a viewer.

  Conventionally, as this type of head-up display device, for example, one described in Patent Document 1 below is known. The head-up display device disclosed in Patent Document 1 includes a display that emits display light, a plane mirror that reflects display light emitted from the display, and a concave mirror that further reflects the display light reflected by the plane mirror (reflective member). ), A housing that accommodates the display, the plane mirror, and the concave mirror, and the display includes a liquid crystal display element (display element) that emits display light, and a hot mirror disposed on the front side of the liquid crystal display element. The display light provided and reflected by the concave mirror is projected onto the windshield (projection member) of the vehicle through a translucent cover (translucent part) formed in the housing to display a virtual image to the viewer (driver). Is.

JP 2013-174855 A

  In the head-up display device described in Patent Document 1 described above, a λ / 4 plate (retardation plate) having a retardation value of several tens of nanometers is attached to one surface of the hot mirror opposite to the liquid crystal display element. Sometimes. At this time, the display light emitted from the λ / 4 plate includes both the P wave component and the S wave component, and is irradiated onto the windshield through the plane mirror and the concave mirror.

  By the way, when a viewer who visually recognizes a virtual image wears polarized sunglasses, the polarized sunglasses generally cuts the S wave component from its function, but the P wave component is added to the display light irradiated to the windshield. Since it is included, the viewer can visually recognize the virtual image.

On the other hand, when the viewer removes the polarized sunglasses that the viewer has been wearing, the value of the brightness of the virtual image (at the time of naked eyes) is due to the pasting of the λ / 4 plate on one surface described above. Thus, it has been found that it does not exceed a certain luminance value. Therefore, it is desired to provide a head-up display device capable of improving the visibility of the virtual image when the naked eye is in order to make the luminance of the virtual image exceed the predetermined luminance value.
Accordingly, the present invention is directed to providing a head-up display device capable of improving the visibility of a virtual image when the naked eye is present in order to cope with the above-described problems.

  The present invention includes a display that emits display light, a reflective member that reflects the display light, a housing that houses the display and the reflective member, and the display element that emits the display light as the display. A hot mirror disposed on the front side of the display element is provided, and the display light reflected by the reflecting member is projected onto a projection member through a light transmitting portion formed in the housing to display a virtual image to a viewer In the head-up display device that performs the above, a high retardation film is disposed in the optical path of the display light from the hot mirror to the projection member.

  In the invention, it is preferable that the high retardation film is attached to one surface of the hot mirror which is opposite to the display element side.

  According to the present invention, it is possible to provide a head-up display device that can achieve the intended purpose and can improve the visibility of a virtual image with the naked eye.

1 is a schematic view of a head-up display device according to an embodiment of the present invention. Sectional drawing of the display apparatus by the embodiment. Sectional drawing which shows the indicator and backlight unit by the embodiment. Sectional drawing of the display apparatus by the 1st modification of the embodiment. Sectional drawing of the display apparatus by the 2nd modification of the embodiment. Sectional drawing of the display apparatus by the 3rd modification of the embodiment.

  Hereinafter, an embodiment in which the present invention is applied to a head-up display device for a vehicle will be described with reference to FIGS.

  As shown in FIG. 1, the head-up display device is configured such that the display light L projected by the display device 12, which is a display unit disposed on the instrument panel 11 of the vehicle 10, is generated by the windshield 13 of the vehicle 10 that is a projection member. It is reflected in the direction of the driver (viewer) 14 to display a virtual image. In other words, the head-up display device irradiates (projects) the display light L emitted from a display device (described later) of the display device 12 onto the windshield 13 (the projection member), and a display image (virtual image) obtained by the irradiation. ) V is made visible to the driver 14. Thus, the driver 14 can observe the virtual image V superimposed on the landscape.

  As shown in FIG. 2, the display device 12 mainly includes a backlight unit 20, a display 30, a first reflector 40, a second reflector 50, and a housing 60.

  As shown in FIG. 3, the backlight unit 20 dissipates heat emitted from the light source 22 composed of white light emitting diodes arranged on the light source substrate 21 composed of an aluminum substrate with a space therebetween. A heat radiating member 23 that is in close contact (contact) with the back surface of the light source substrate 21, a lens member 24 that receives illumination light from the light source 22 and emits it toward the display 30, and the light source 22 and the lens member 24. A light source case 25 is provided, and the light source case 25 is made of, for example, milky white synthetic resin having good light reflectivity.

  The heat dissipating member 23 is made of a heat sink formed of a metal material having high thermal conductivity such as aluminum, and mounts a first mounting portion 23a for mounting the light source substrate 21 and a support body to be described later. A second placement portion 23b for placing the device and a plurality of heat radiation fins 23c that can come into contact with air (atmosphere) outside the housing 60. In this case, the second placement portion 23b is provided on the display 30 side. It is formed as a wall portion extending substantially in an L shape toward the surface. In addition, the heat radiating member 23 is being fixed to the housing 60 using the fixing means suitably.

  The display 30 is disposed on the front side of the backlight unit 20. In this case, the display 30 is a TFT-type liquid crystal display element (display) that transmits (illuminates) the display light L through the illumination light from the backlight unit 20 (that is, the illumination light emitted from the lens member 24). Element) 31, a hot mirror 32 as a transmissive reflection member that is inclinedly disposed on the front side (directly above) of the liquid crystal display element 31 so as to be separated from the liquid crystal display element 31, and the liquid crystal display element 31 and the hot mirror 32. A case member 33 to be disposed (stored or held), a support body 34 positioned at the peripheral edge of the back surface of the liquid crystal display element 31, and a high retardation film 35 attached to the surface (one surface) 32a of the hot mirror 32. And a polarizing member 36 attached to the back surface (the other surface) 32b of the hot mirror 32.

  Note that a light diffusing plate (not shown) for making the illumination light from the backlight unit 20 uniform may be disposed between the liquid crystal display element 31 and the support 34 as necessary.

  The liquid crystal display element 31 is, for example, a liquid crystal display panel in which a front-side polarizing plate and a rear-side polarizing plate are respectively attached to the front and back surfaces of a liquid crystal cell, and displays predetermined information by illumination light emitted from the backlight unit 20. It is. That is, the liquid crystal display element 31 emits the display light L by the illumination light from the light source 22 arranged (mounted) on the light source substrate 21 located behind the liquid crystal display element 31. The predetermined information includes, for example, vehicle speed, engine speed, fuel consumption, time, navigation, and the like.

  The hot mirror 32 is disposed in the optical path of the display light L from the liquid crystal display element 31 to a cold mirror (to be described later) of the first reflector 40. Specifically, the hot mirror 32 is disposed in the optical path of the display light L that extends from the liquid crystal display element 31 to the cold mirror in a state in which a front opening described later of the case member 33 is closed.

  Further, the hot mirror 32 efficiently transmits the display light L composed of visible light emitted from the liquid crystal display element 31 to the cold mirror side, and also includes a translucent cover and a second reflector, which will be described later, formed on the housing 60. 50 has a characteristic of absorbing (reflecting) infrared rays (heat rays) of sunlight (external light) irradiated to the display 30 (liquid crystal display element 31) inside the housing 60 through the concave mirror described later and the cold mirror. Yes.

  In addition, although detailed illustration here is abbreviate | omitted, the hot mirror 32 is a transparent glass substrate which is a substantially rectangular acrylic resin, and the surface (namely, surface which faces the said cold mirror in FIG. 2) of the said glass substrate. And a reflective layer made of a multilayer interference film.

  The case member 33 is formed in a substantially frame shape by a synthetic resin material or a metal material, and has a base portion 33a having a substantially frame shape that holds a peripheral portion on the back side of the hot mirror 32 that is arranged to be inclined, and a liquid crystal display element A cover portion 33b having a flange shape that covers the peripheral edge of the front surface of 31 and a drooping portion 33c that hangs behind the cover portion 33b so as to surround the support 34 are integrally formed.

  The base 33 a has a frame shape that penetrates the top and bottom, is positioned between the liquid crystal display element 31 and the hot mirror 32, and guides the display light L emitted from the liquid crystal display element 31 to the hot mirror 32. It has an opening 33d for the purpose.

  In this case, the hot mirror 32 is placed on the base 33a so as to close the front opening 33e located on the front side of the opening 33d, and the display light L emitted from the liquid crystal display element 31 is The light passes through the opening 33d and the hot mirror 32 and is guided to the first reflector 40 side.

  The support 34 is formed of a conductive material (metal material), has a function as a support member that supports the liquid crystal display element 31, and guides the illumination light emitted from the backlight unit 20 to the liquid crystal display element 31. Open hole 34a. In this example, the support 34 is configured such that a required portion on the bottom surface thereof is placed on the second placement portion 23 b provided in the heat dissipation member 23.

  As the high retardation film 35, a high retardation film having a retardation value of 3000 nanometers or more, preferably 3000 to 30000 nanometers can be applied, and is arranged in the optical path of the display light L from the hot mirror 32 to the windshield 13. (Arrangement). Specifically, in this embodiment, the high retardation film 35 is affixed to the surface 32a of the hot mirror 32 on the side opposite to the liquid crystal display element 31 side. In addition, when the retardation value is less than 3000 nanometers, when a display (virtual image) is observed through polarized sunglasses, a strong interference color is exhibited, and thus good visibility cannot be ensured.

  Further, the high retardation film 35 further increases the light reflection efficiency of the display light L reflected from the windshield 13 toward the driver 14 (that is, the S wave component of the P wave component and the S wave component included in the display light L). It has a function as a retardation film to enhance. In addition, although detailed illustration here is abbreviate | omitted, the high retardation film 35 has a slow axis of 0 degree | times, 30 degree | times, 45 degree | times, and 90 degree | times with respect to the absorption axis (polarization axis | shaft) of the polarizing member 36, for example. .

  The polarizing member 36 is a polarizing plate configured such that its polarizing axis is the same as the polarizing axis of the front side polarizing plate. Here, like the hot mirror 32, the polarizing member 36 has a function of blocking external light applied to the liquid crystal display element 31.

  The first reflector 40 includes a cold mirror 41 as a plane mirror located above (directly above) the hot mirror 32, and an attachment member 42 for attaching and fixing the cold mirror 41 using predetermined attachment means. have.

  The cold mirror 41 includes a substantially rectangular glass substrate 41a and a first reflecting layer 41b formed on one surface of the glass substrate 41a (a surface facing a concave mirror described later of the second reflector 50). The first reflective layer 41b is composed of multilayer interference films having different film thicknesses, and is formed by a method such as vapor deposition.

  The cold mirror 41 is arranged in an inclined state at a position where the display light L emitted from the liquid crystal display element 31 and transmitted through the hot mirror 32 is reflected toward the second reflector 50 (the concave mirror). Established. The attachment member 42 is made of, for example, a black synthetic resin material, and is fixed to the housing 60 using an appropriate fixing means.

  The second reflector 50 includes a concave mirror 51 as a reflecting member that reflects the display light L from the cold mirror 41 (that is, the liquid crystal display element 31), and a mirror holder 52 that holds the concave mirror 51.

  The concave mirror 51 is formed by vapor-depositing a second reflective layer 51a on a resin substrate made of polycarbonate having a concave surface. The concave mirror 51 is disposed in an inclined state at a position where the second reflecting layer 51a faces the cold mirror 41 and a translucent cover (to be described later) of the housing 60 and faces the translucent cover.

  The concave mirror 51 reflects (projects) the display light L from the cold mirror 41 toward the translucent cover side (the windshield 13 side of the vehicle 10). This means that the concave mirror 51 enlarges the display light L reflected by the cold mirror 41 and projects the enlarged display light L onto the windshield 13 through the translucent cover. The concave mirror 51 is bonded to the mirror holder 52 with a double-sided adhesive tape. The mirror holder 52 is made of a synthetic resin material, and is fixed to the housing 60 using appropriate fixing means.

  The housing 60 is formed of, for example, a black synthetic resin material or aluminum die cast, and includes an upper case body 61 and a lower case body 62 each having a substantially concave shape in cross section, and the upper case body 61 and the lower case body. In the space 63 that is an internal space formed by the body 62, the backlight unit 20, the display 30, the first reflector 40 including the cold mirror 41, the second reflector 50 including the concave mirror 51, and the like are stored (accommodated). )doing.

  The upper case body 61 is formed with an opening window portion 64 that opens at the upper portion (the windshield 13 side of the vehicle 10) where the concave mirror 51 is disposed, and the display light L reflected by the concave mirror 51 is an opening window. It will pass through part 64.

  The housing 60 is provided with a translucent cover 65 which is a translucent part so as to close the opening window part 64. The translucent cover 65 is formed of a translucent synthetic resin material (for example, acrylic resin) and has a function as a light transmissive member that transmits (passes) the display light L reflected by the concave mirror 51. Yes.

  In other words, the display light L reflected by the cold mirror 41 and the concave mirror 51 is projected onto the windshield 13 through the translucent cover 65 formed on the housing 60, whereby a virtual image V display (virtual image display) is displayed on the driver 14. Will be done. Reference numeral 66 denotes a hole formed in the bottom of the lower case body 62, and the heat radiating member 23 is disposed in the hole 66 so as to close the hole 66.

  The display device 12 is configured by the above-described units. In such a configuration, the illumination light emitted from the light source 22 includes the P wave component and the S wave component before entering the liquid crystal display element 31, and the P wave component is emitted at the stage emitted from the liquid crystal display element 31. It is completely cut to have only the S wave component.

  After that, when only the S wave component illumination light passes through the polarizing member 36, the hot mirror 32 and the high retardation film 35 and is emitted as the display light L from the high retardation film 35 (display 30), the P wave component is changed. The P wave component and the S wave component are generated again. Then, the display light L including the P wave component and the S wave component is sequentially reflected by the cold mirror 41 and the concave mirror 51, then passes through the translucent cover 65 and is projected onto the windshield 13. Reflected in the direction of 14.

  Here, when the display light L including the P wave component and the S wave component is reflected by the windshield 13 toward the driver 14, the surface 32a of the hot mirror 32 has a high height of 3000 nanometers or more in this example. A retardation film 35 is pasted.

  And, due to this, the light reflection efficiency of the S wave component on the windshield 13 becomes dramatically better (improved) than the λ / 4 plate that has been conventionally adopted, As a result, it has been found that the luminance value of the virtual image V when the driver 14 is not wearing polarized sunglasses exceeds the certain predetermined luminance value. Specifically, it has been found that the luminance value of the virtual image V when the naked eye is used when the high retardation film 35 is adopted is several thousand candela higher than the predetermined luminance value, thereby the virtual image V when the naked eye is naked. Visibility can be improved.

  As described above, in the present embodiment, the display 30 is provided with the liquid crystal display element 31 that emits the display light L and the hot mirror 32 disposed on the front side of the liquid crystal display element 31. Since the high retardation film 35 is disposed in the optical path of the display light L reaching the glass 13 (for example, the surface 32a of the hot mirror 32), the light reflection characteristics of the high retardation film 35 are utilized. It is possible to provide a head-up display device capable of improving the visibility of the virtual image V when the naked eye is present.

  In addition, this invention is not limited by the above-mentioned embodiment and drawing. Changes (including deletion of constituent elements) can be added to the embodiments and the drawings as appropriate without departing from the scope of the present invention. For example, in the above-described embodiment, the high retardation film 35 is disposed (attached) on the surface 32a of the hot mirror 32. However, the high retardation film 35 is formed from the hot mirror 32 to the windshield. Any configuration may be employed as long as it is disposed in the optical path of the display light L reaching 13.

  Specifically, as shown in FIG. 4, as a first modification, the high retardation film 35 is disposed on the back surface 65a of the translucent cover 65 in a positional relationship facing the concave mirror 51 (second reflective layer 51a). As a second modification, as shown in FIG. 5, the high retardation film 35 is applied to the surface 41c of the first reflective layer 41b in a positional relationship facing the second reflective layer 51a. Alternatively, the high retardation film 35 may be replaced with a cold mirror 41 (first reflector 40) and a concave mirror 51 (second reflector) as shown in FIG. 50) (in an inclined state). In the case of this third modification, the high retardation film 35 may be attached to the translucent substrate 70 fixed to the housing 60 using an appropriate fixing means.

  Further, although not shown in detail here, the high retardation film 35 is disposed on the surface of the translucent cover 65 which is in a positional relationship facing the windshield 13 (that is, the surface opposite to the back surface 65a). The high retardation film 35 may be disposed on the surface of the second reflective layer 51a in a positional relationship facing the first reflective layer 41b (may be pasted). ).

  Moreover, although embodiment mentioned above demonstrated the example in which the display light L emitted from the indicator 30 is projected on the windshield 13, for example, the display light L is favorably reflected in the driver | operator 14 direction on the windshield 13. FIG. A combiner film may be provided, or the display light L may be projected onto a dedicated reflector (for example, a combiner) different from the windshield 13.

12 Display device 13 Windshield (projection member)
14 Driver (viewer)
20 Backlight Unit 22 Light Source 30 Display 31 Liquid Crystal Display Element (Display Element)
32 Hot mirror 35 High retardation film 36 Polarizing member 40 First reflector 41 Cold mirror 50 Second reflector 51 Concave mirror (reflecting member)
60 Housing 65 Translucent cover (translucent part)
L Display light V Virtual image (display image)

Claims (2)

A display that emits display light; a reflection member that reflects the display light; and a housing that houses the display and the reflection member.
As the display, a display element that emits the display light, and a hot mirror disposed on the front side of the display element are provided,
In a head-up display device that displays a virtual image for a viewer by projecting the display light reflected by the reflecting member onto a projection member through a light transmitting portion formed in the housing.
A head-up display device, wherein a high retardation film is disposed in an optical path of the display light from the hot mirror to the projection member. The head-up display device according to claim 1, wherein the high retardation film is attached to one surface of the hot mirror that is opposite to the display element side.

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