JP2007086387A - On-vehicle display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle display device capable of preventing the damage of a display unit by restraining the temperature rise of the display unit. <P>SOLUTION: The on-vehicle display device is equipped with: a liquid crystal display element 31 constituted by providing a liquid crystal cell 31a between a pair of polarizing films 31b and 31c; and a light source 32 radiating illuminating light to the liquid crystal display element 31, and projects and displays a display image L obtained by transmitting the illuminating light through the liquid crystal display element 31 on a display member comprising a windshield provided in driver's front field. The incident side polarizing film 31b provided on the light source 32 side is held on a light control member 34 provided by leaving space between the liquid crystal cell 31a and the light control member 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device for a vehicle, and is particularly suitable for a display device for a vehicle that displays a virtual image by reflecting display light emitted from a light-emitting display.

  Conventionally, various display devices such as head-up displays as shown in Patent Documents 1 and 2 have been proposed. In these display devices, as shown in FIG. 3, the display image L projected by the display device B provided on the dashboard A of the vehicle is reflected by the windshield C toward the driver D to display a virtual image V. There is something to do.

In addition, the display device B is configured by, for example, a display E that includes a light source and a liquid crystal display element and displays and displays a display image L, and a concave mirror F housed in a housing G (see FIG. 4). The display image L emitted from the display device E is reflected by the concave mirror F and projected onto the windshield C. The driver D can visually recognize the virtual image V superimposed on the landscape.
Japanese Utility Model Publication No. 63-9041 JP-A-9-15555

  The display device B as described above needs to perform display with high luminance using a light source that performs high-luminance output in order to provide a vehicle display device with good visibility even in the daytime. There is a possibility that the display E is heated to a high temperature and damaged by the light energy. Therefore, there has been a demand for a structure that prevents the display E from exceeding the heat-resistant temperature upon receiving light energy from the light source.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle display device capable of preventing the display device from being damaged by suppressing an increase in the temperature of the display device. .

  In order to solve the above-described problems, a vehicle display device according to the present invention has a display element having a liquid crystal cell between a pair of polarizing members, and illumination light to the display element. A vehicle display device for projecting and displaying a display image obtained by transmitting the illumination light through the display element on a display member provided in a driver's front visual field, The vehicle display device, wherein the polarizing member provided on the light source side is held by a translucent member provided through a space with the liquid crystal cell.

  In addition, as described in claim 2, in the vehicle display device according to claim 1, the translucent member is provided between the liquid crystal cell and the light source, and is a flat translucent substrate. And a trim filter provided on one surface of the translucent substrate, and the polarizing member is held on the other surface of the translucent substrate.

  In addition, as described in claim 3, in the vehicle display device according to claim 2, the trim filter is provided on a surface on the light source side of the translucent substrate, and the liquid crystal of the translucent substrate is provided. The polarizing member is held on a cell side surface.

  According to a fourth aspect of the present invention, in the vehicle display device according to the first aspect, the translucent member is held in contact with a casing made of a metal material.

  In addition, as described in claim 5, in the vehicle display device according to claim 1, the translucent member is provided between the liquid crystal cell and the light source, and is a flat translucent substrate. And a trim filter provided on at least one surface of the translucent substrate, and the polarizing member is held by the trim filter.

  The present invention relates to a display device for a vehicle that displays a virtual image by reflecting display light emitted from a light-emitting display device, and relates to a display device for a vehicle that can suppress a temperature rise of the display device and prevent damage to the display device. Can provide.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a vehicle display device according to an embodiment of the present invention applied to a head-up display will be described as an example with reference to the accompanying drawings. The head-up display reflects a display image L projected by a display device provided on a dashboard of the vehicle by a windshield (display member) serving as a display object in the direction of the driver to display a virtual image. .

  As shown in FIG. 1, the display device includes a concave mirror 2 and a display 3 in a housing 1 provided so as to be embedded in an upper part of a dashboard of a vehicle.

  The housing 1 is made of a light-shielding synthetic resin material, and is provided with a window portion 11 that opens an upper portion (a windshield side) where the concave mirror 2 is disposed, and a hole portion 12 for projecting a heat sink described later. ing. In addition, a light shielding wall 13 is provided in the housing 1 to prevent the sunlight from directly entering the display device and making it difficult to see the virtual image V (washout). In this embodiment, the light shielding wall 13 is integrated with the housing 1. Is formed. Further, a cover 14 made of a light-transmitting synthetic resin material (for example, acrylic) is provided on the upper portion of the housing 1 so as to close the window portion 11.

  The concave mirror 2 is formed by vapor-depositing a reflective layer on a synthetic resin substrate made of polycarbonate having a concave surface 21. The concave mirror 2 is provided so that the concave surface 21 faces the display device 3 and the cover 14, and reflects the display image L projected from the display device 3 while enlarging it to the windshield side. The concave mirror 2 is provided so that the angle can be adjusted so that an observer (for example, a driver) can easily view the display image L projected on the windshield.

  The display 3 emits and outputs information to be displayed as a display image L. The display 3 is provided in the housing 1 so that the surface on the emission side of the display image L faces the concave mirror 2, and the optical axis of the display image L is displayed. Is fixed and held at such a position and orientation as to intersect the concave surface 21 of the concave mirror 2. As shown in FIG. 2, the display 3 includes a liquid crystal display element (display element) 31, a light source 32, a diffusion plate 33, a light control member (translucent member) 34, a hot mirror 35, a heat sink 36, and a housing. 37, mainly.

  The liquid crystal display element 31 includes a liquid crystal cell 31a in which liquid crystal is sealed between a pair of glass substrates provided with transparent electrodes, and polarizing films (polarizing members) 31b and 31c provided on the front and rear sides of the liquid crystal cell 31a. This is for transmitting the illumination light from the light source 32 and outputting the display image L. In this case, the polarizing films 31b and 31c include the incident-side polarizing film (polarizing member) 31b held by the heater 34 provided on the illumination light incident side (light source 32 side) in the liquid crystal cell 31a and the illumination light in the liquid crystal cell 31a. Output side polarizing film (polarizing member) 31c held by a hot mirror 35 provided on the output side (concave mirror 2 side). As the liquid crystal display element 31, for example, a transmissive TFT type liquid crystal display element can be applied, and information (for example, vehicle speed, engine speed, etc.) to be displayed by a drive circuit (not shown) is in the form of numerical values or bar graphs. Can be displayed.

  In addition, a light reflection preventing layer (not shown) is formed on both end faces of the liquid crystal cell 31a to reduce the loss of light at the interface between the liquid crystal cell 31a and the air as well as reducing the reflected light. The illumination light (display image L) can be transmitted well.

  A plurality of light emitting diodes can be applied to the light source 32 and is held on the wiring board 38. The light source 32 is provided in such a direction and position as to transmit and illuminate the liquid crystal display element 31 and the illumination light (display image L) reaches the concave mirror 2.

  The light diffusing plate 33 can be formed of a light-transmitting synthetic resin member having at least one surface subjected to uneven processing, and is provided between the light source 32 and the liquid crystal display element 31. In this case, the diffuser plate 33 is applied with an uneven shape on the surface through which the illumination light is transmitted. However, by further providing a lens array in consideration of the directivity and arrangement of the light source 32, the diffuser plate 33 may be provided integrally or separately. , Display output with more uniform illumination can be expected.

  The light control member 34 is provided on the back side (light source 32 side) of the liquid crystal cell 31a at a predetermined interval, and a trim filter 34b is formed on the back side (on the light source 32 side) of the transparent substrate 34a. The incident side polarizing film 31b is stuck and held on the surface of the transparent substrate 34a (the surface facing the liquid crystal cell 31a). Therefore, the incident-side polarizing film 31b heated by the light source 32 is not the liquid crystal cell 31a provided through the space, but the translucency of the light control member 34 held in contact with the incident-side polarizing film 31b. It can be efficiently transmitted to the substrate 34a. The dimming member 34 reflects light in a predetermined wavelength region (for example, light in the blue wavelength region and light in the vicinity of 590 nm) out of the illumination light from the light source 32 by the trim fill 34b. Light can be transmitted and illumination with a desired color can be performed.

  Further, as the light control member 34, for example, when only red or green illumination is required, a trim filter that reflects light in the blue wavelength region or light in the middle region between red and green and transmits light that is not reflected is used. Therefore, it is possible to reduce light in an unnecessary wavelength range that reaches the incident-side polarizing film 31b. Therefore, by providing the trim filter 34b on the light source 32 side of the transparent substrate 34a and holding the incident side polarizing film 31b on the liquid crystal cell 31a side, the incident side polarizing film is caused by extra light energy from the light source 32 that is not necessary for illumination. It is possible to prevent the temperature of 31b and the liquid crystal cell 31a from rising.

  The hot mirror 35 efficiently transmits the display image L (visible light) emitted from the display 3, and among infrared rays incident on the display 3 through the windshield, the cover 14, and the concave mirror 2, infrared rays (heat rays) ) To reduce the temperature rise of the liquid crystal display element 31. The hot mirror 35 is provided between the liquid crystal cell 31 c and the concave mirror 2 so that the transmission surface (reflection surface) is perpendicular or inclined with respect to the optical path of the display image L. Further, on the surface of the hot mirror 35 facing the liquid crystal display element 31, the exit side polarizing film 31 c is stuck and held. Therefore, the exit-side polarizing film 31c heated by sunlight efficiently transmits the heat not to the liquid crystal cell 31a provided through the space but to the hot mirror 35 held in contact with the exit-side polarizing film 31c. be able to.

  A metal material having high thermal conductivity such as aluminum can be applied to the heat sink 36, and the wiring board 39 is held by screwing a fixing member (not shown) made of screws or bolts. Further, the heat sink 36 can transmit the heat generated by the light source 32 through the wiring board 39, and can dissipate (heat radiate) heat to the air outside the housing 1 by the heat radiating fins 36 a protruding from the hole 12 of the housing 1.

  The housing 37 is for holding the liquid crystal cell 31, the light control member 34, the hot mirror 35, and the heat sink 36 at predetermined positions of the housing 1, and in this case, is formed in a cylindrical shape that opens at both ends. Made of synthetic resin material. The housing 37 can also be made of a material having a high heat transfer coefficient, such as a metal material. In this case, not only the above-described components but also the components heated by the light source 32 or sunlight are used. It can be expected that heat is efficiently transmitted and radiated to the outside of the housing 1 through the heat sink 36.

  Such a display device includes a liquid crystal display element 31 having a liquid crystal cell 31a between a pair of polarizing films 31b and 31c, and a light source 32 for irradiating the liquid crystal display element 31 with illumination light, and the illumination light. Is a vehicle display device that projects and displays a display image L obtained by passing through the liquid crystal display element 31 on a display member made of a windshield provided in the driver's front visual field, and is provided on the light source 32 side. The incident-side polarizing film 31b is held by a light control member 34 provided through a space with the liquid crystal cell 31a.

  Therefore, by holding the incident side polarizing film 31b on the light control member 34, the heat of the emission side polarizing film 31c heated by the light source 32 is efficiently transmitted from the contact portion of the light transmitting substrate 34a to the light transmitting substrate 34a. Therefore, the liquid crystal cell 31a provided through the space has a structure in which heat is not easily transmitted. For this reason, the liquid crystal cell 31a can be prevented from being heated by the light source 32, and damage to the liquid crystal can be prevented.

  The light control member 34 is provided between the liquid crystal cell 31a and the light source 32, and is configured by a flat plate-like transparent substrate 34a and a trim filter 34b provided on one surface of the transparent substrate 34a. The incident side polarizing film 31b is held on the other surface of the translucent substrate 34a. Therefore, since the incident side polarizing film 31b can be held at a position away from the liquid crystal cell 31a in the optical path of the illumination light of the light source 32, the heat of the incident side polarizing film 31b heated by the light source 32 is transmitted to the liquid crystal cell 31a. It becomes a difficult structure, and the temperature rise of the liquid crystal cell 31a can be reduced.

  Further, by providing a light reflection preventing layer on both end faces of the liquid crystal cell 31a, reflection of light between the liquid crystal cell 31a and the space is reduced, and illumination light from the light source 32 is efficiently output as a display image L. Therefore, illumination with high luminance can be performed without increasing the luminance of the light source 32 excessively. For this reason, since heat generation due to extra luminance can be reduced, the liquid crystal cell 31a can be prevented from being heated to a high temperature by the heat of the light source 32. In the embodiment of the present invention, the liquid crystal cell 31a is provided with the light reflection preventing layers on both end faces. For example, illumination light (display image L) from the hot mirror 35 and the polarizing films 31b and 31c is shown. A light reflection preventing layer can be provided between the member that transmits light and the space, and the same effect can be obtained.

  In the embodiment of the present invention, the head-up display composed of the above-described components has been described as an example. However, the present invention is not limited to this, and the configuration and processing have the same effects. For example, the incident-side polarizing film 31b may be held by the trim filter 34b, or held by a translucent member such as a transparent glass substrate instead of the light control member 34. It may be done. Further, in the optical path of the illumination light from the light source 32, another member such as a translucent panel heater may be interposed between the incident side polarizing film 31b and the liquid crystal cell 31a.

  Further, in the embodiment of the present invention, the trim filter that reflects the light in the blue wavelength region or the light in the middle region between red and green and transmits the light that is not reflected has been described as an example. It is also possible to provide a structure in which trim filters are provided on both sides of the filter, and the incident side polarizing film is held by the trim filter on one side. For example, a trim filter that reflects light in the blue wavelength region is provided on one surface of the translucent substrate, and a trim filter that reflects light in the middle region between red and green is provided on the other surface, and any one of the trim filters The incident-side polarizing film can be attached to and held on the substrate.

  Further, in the embodiment of the present invention, the head-up display in which the driver visually recognizes the display image L by reflecting the display image L on the windshield as a display member is described as an example. (Combiner) may be used.

The side view which shows embodiment of this invention by a partial cross section. Sectional drawing which shows the indicator of embodiment same as the above. The schematic block diagram of the head-up display which shows a prior art example. The side view which shows a prior art example same as the above.

Explanation of symbols

2 Concave mirror 3 Display 31 Liquid crystal display element (display element)
31a Liquid crystal cell 31b Incident side polarizing film (polarizing member)
31c Output side polarizing film (polarizing member)
32 Light source 34 Light control member (translucent member)
35 hot mirror

Claims (5)

A display element having a liquid crystal cell between a pair of polarizing members, and a light source for irradiating the display element with illumination light, and operating a display image obtained by transmitting the illumination light through the display element A vehicle display device that projects and displays on a display member provided in the front view of the person,
The vehicle display device, wherein the polarizing member provided on the light source side is held by a translucent member provided through a space with the liquid crystal cell.   The translucent member is provided between the liquid crystal cell and the light source, and is constituted by a flat translucent substrate and a trim filter provided on one surface of the translucent substrate, The vehicle display device according to claim 1, wherein the polarizing member is held on the other surface of the conductive substrate.   3. The trim filter is provided on a surface on the light source side of the translucent substrate, and the polarizing member is held on a surface on the liquid crystal cell side of the translucent substrate. Vehicle display device.   The vehicle display device according to claim 1, wherein the translucent member is held in contact with a casing made of a metal material.   The translucent member is provided between the liquid crystal cell and the light source, and is configured by a flat translucent substrate and a trim filter provided on at least one surface of the translucent substrate, and the trim The vehicle display device according to claim 1, wherein the polarizing member is held in a filter.

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