Abstract:
Disclosed is a display device capable of achieving a decorative effect by utilizing a color filter at the front of a light-emitting display unit. Also disclosed is a meter device using the display device. Specifically disclosed is a display device comprising a light-emitting display unit and a color filter, which is arranged at the front of the light-emitting display unit. A light-emitting element for decoration is provided on the outside of the light-emitting display unit. The color filter is provided with a light-discharging surface for discharging the light from the light-emitting element for a decorative appearance in the forward direction.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a display device used in a meter device, which displays travelling states such as vehicle speed in a passenger vehicle or the like, and a meter device using the display device. 
     BACKGROUND OF THE INVENTION 
     Conventionally, for this type of display devices, configurations as disclosed in Patent Documents 1 to 3 have been proposed. 
     In a conventional configuration described in Patent Document 1, a plurality of panel switches are arranged around a liquid crystal panel, and a light guide lens is arranged between the liquid crystal panel and the panel switches. Light from the liquid crystal panel is guided to the panel switches via the light guide lens to illuminate the panel switches. Thus, in Patent Document 1, a light source dedicated to illuminate the panel switches is not required. 
     In a conventional configuration described in Patent Document 2, a light control means is provided between a plurality of light sources for vehicle speed display and a plurality of light sources for a shift range display. The light control means allows light from the light sources for vehicle speed display to be radiated to a shift range display, which serves as backlight for the shift range display. In contrast, light from the light sources for the shift range display is prevented from being radiated to the vehicle speed display, thereby preventing illumination unevenness in the vehicle speed display. 
     In a conventional configuration described in Patent Document 3, a front surface of a light shielding case having a meter therein is coated with a transparent case. A corner portion between a front wall portion and a side wall portion of the transparent case has a reflection portion for reflecting external light (light of a head lamp) entering from an edge of the side wall portion outward without allowing the light to pass to the front wall portion. This reflection portion shields the external light entering the light shielding case through the transparent case, thereby suppressing illumination unevenness in a meter display. 
     In a conventional configuration described in Patent Document 4, light from a light source is reflected on two reflection portions through an air layer to allow a front panel of a meter to perform surface-emitting. With this configuration, since an illumination chamber formed of an air layer can be formed, the whole of the front panel can be illuminated without using any planar illuminant, achieving cost reduction. 
     In the conventional configuration described in Patent Document 5, a reflecting mirror is provided at the rotational center of an indicator of a tachometer, and display light indicating vehicle travelling speed is emitted from a display to the reflecting mirror through a smoke glass so that the driver can see the travelling speed from display reflected by reflected light. With this configuration, since there is no need to provide a smoke glass in front of the meter, visibility of the tachometer indicator is ensured.
     Patent Document 1: Japanese Laid-Open Patent Publication No. 2006-59565   Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-145334   Patent Document 3: Japanese Laid-Open Patent Publication No. 2000-16118   Patent Document 4: Japanese Laid-Open Patent Publication No. 2001-281007   Patent Document 5: Japanese Laid-Open Patent Publication No. 2005-233276   

     However, each of the conventional configurations has the following problems. 
     In the configuration described in Patent Document 1, the whole of the panel switches is illuminated by light from the liquid crystal panel. Illumination of the panel switches in Patent Document 1 utilizes light of a liquid crystal display screen. Accordingly, the light amount of the switches depends on the light amount of the backlight for the liquid crystal screen to display the switches. Thus, when it is attempted to increase the light amount of the switches, the liquid crystal display screen becomes too bright. Accordingly, in the case of adopting this configuration for decorative illumination, it is difficult to obtain a desired decorative design due to limitations by brightness of the liquid crystal display screen or the like. Moreover, in the configuration described in Patent Document 1, an area for ensuring switch light is required in the liquid crystal screen, resulting in an increase in the whole of the liquid crystal display device in size. Further, in the case where this configuration is adopted to perform decorative illumination away from the liquid crystal screen, a long light guide lens is needed, and it is difficult to incorporate such a light guide lens in the limited space in the display device. 
     In the configuration described in Patent Document 2, the whole of the shift range display is illuminated by light from the light sources for vehicle speed display, which is effective in preventing illumination unevenness. However, it is difficult to satisfactorily display the vehicle speed and supply decorative illumination at the same time. Moreover, in the configuration described in Patent Document 2, the light control means for controlling light is needed to be provided between the plurality of light sources for vehicle speed display and the plurality of light sources for the shift range display, which makes the configuration complicated. 
     In the configuration described in Patent Document 3, the transparent case is provided with the reflection portion for shielding external light. That is, the configuration in Patent Document 3 serves to prevent light from entering into the case, not to utilize light, and therefore, the decorative effect of illumination cannot be expected. 
     In the configuration described in Patent Document 4, the reflection portion (in this embodiment, the prism-like portion) dedicated to guide light from the light source to the front panel of the meter is required. Despite the fact that cost reduction can be achieved, the number of components increases and the configuration becomes complicated. Moreover, in the configuration described in Patent Document 4, in the case of performing a decorative function, decorative and display functions need to be satisfied at the same time and thus, as described above, a desired decorative design cannot be ensured. 
     In the configuration described in Patent Document 5, since it is needed to provide the dedicated large and expensive reflecting mirror at the rotational center of the indicator of the tachometer, the number of components increases and moreover, unless the reflection angle of the reflecting mirror is accurately set, the display screen may be distorted. For this reason, the configuration described in Patent Document 5 inevitably leads to high costs. Also in the configuration described in Patent Document 5, in the case of performing a decorative function, decorative and display functions need to be satisfied at the same time and thus, as described above, a desired decorative design cannot be ensured. 
     The present invention is made in consideration of the problems in such conventional techniques. An objective of the present invention is to provide a display device capable of effectively achieving a decorative effect by utilizing a portion of a color filter at the front of a light-emitting display unit with a simple configuration, and a meter device using the display device. 
     SUMMARY OF THE INVENTION 
     To achieve the foregoing objective and in accordance with one aspect of the present invention, a display device is provided that includes a light-emitting display unit and a color filter arranged at the front of the light-emitting display unit. The device is characterized in that a light-emitting element is provided in the outside of the light-emitting display unit, and a light-discharging surface for discharging light from the light-emitting element in a forward direction is formed at an end of the color filter. 
     Therefore, in the display device according to the present invention, when the light-emitting element emits light, the light-discharging surface of the color filter discharges light received from the light-emitting element. Since the color filter arranged at the front of the light-emitting display unit is locally utilized to perform decorative illumination, the decorative effect can be obtained without increasing the number of components. Moreover, since decorative illumination can be made independent from display illumination, a desired decorative effect can be obtained. 
     In the above described display device, a reflecting surface is preferably provided in a light path of the light-emitting element, and light from the light-emitting element preferably reaches the light-discharging surface through the reflecting surface. 
     In the above described display device, the light-discharging surface is preferably formed by roughening an end of the color filter. 
     A meter device according to the present invention is characterized in that the above described display device is incorporated in an opening of a vehicle instrument panel, the light-emitting display unit displays the vehicle travelling state, and a transparent front plate is provided in the opening so as to cover the color filter. 
     Therefore, the meter device according to the present invention can improve the decorative effect in displaying the vehicle driving state. 
     In the above described meter device, the reflecting surface is preferably provided at a portion of the display device or a vehicle component. 
     In the above described meter device, the color filter is preferably provided with a wall portion for preventing light from the reflecting surface from leaking to a back surface of the color filter. 
     In the above described meter device, the color filter and the front plate are preferably subjected to smoke processing. 
     Effects of the Invention 
     As described above, according to the present invention, in decorative illumination, a highly decorative effect can be obtained even with a simple configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view showing a display device according to one embodiment of the present invention; 
         FIG. 2  is an enlarged cross-sectional view taken along a line  2 - 2  in  FIG. 1 , showing a state where the display device is incorporated in a vehicle instrument panel; 
         FIG. 3  is an enlarged partial cross-sectional view showing a part in  FIG. 2 ; and 
         FIG. 4  is a partial cross-sectional view showing a modification. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A vehicle meter device according to one embodiment of the present invention will be described with reference to the drawings. 
     As shown in  FIGS. 1 and 2 , a meter device  10  in this embodiment is installed in an opening  11   a  of a vehicle instrument panel  11 , and a display device  12  is incorporated thereinto. The meter device is located in the opening  11   a  below a hood portion  11   b  of the instrument panel  11 , and a front plate  13  formed of a transparent plate is arranged at a front frame  16  of the meter device  10  so as to cover a color filter  19  of the display device  12 . The front plate  13  is subjected to smoke processing for setting a predetermined transmittance (for example, 33%) with respect to the brightness of a luminous source. 
     The display device  12  includes a case  15  configured of a horizontally long box-like rear case member  14   a , the front of which is opened, and a front case member  14   b  assembled to the front opened portion of the rear case member  14   a . A plurality of light guiding portions  15   a  are formed in a front upper portion of the front case member  14   b  so as to arrange the light guiding portions  15   a  at intervals in a horizontal direction when viewed from the front. The front frame  16  is attached to the front of the front case member  14   b . A horizontally long display window  16   a  is formed in a front lower portion of the front frame  16 . A display hole  16   b  corresponding to each of the light guiding portions  15   a  of the front case member  14   b  is formed in the front upper portion of the front frame  16 . 
     As shown in  FIG. 2 , a circuit board  17 , which mounts control components and operating components for the display device  12 , is arranged in the case  15 . A light-emitting display unit  18  formed of a VFD (Vacuum Fluorescent Display) is arranged at the front of the circuit board  17  so as to correspond to the display window  16   a  of the front frame  16 . As shown in  FIG. 1 , the light-emitting display unit  18  is provided with a plurality of displays formed of light-emitting elements for displaying the vehicle driving state, and in this embodiment, a vehicle speed display  18   a , a shift position display  18   b , a fuel level display  18   c  and a time display  18   d  are provided. The color filter  19  (e.g. pale red) for converting light of the display elements of the light-emitting display unit  18  (e.g. green) into light of color with less stimulus (e.g. white) is arranged at the front of the light-emitting display unit  18 . The color filter  19  is subjected to smoke processing for setting a predetermined transmittance (for example, about 25%) with respect to brightness of a luminous source. 
     As shown in  FIG. 2 , a display plate  20  is arranged between the light guiding portions  15   a  of the front case member  14   b  and the display hole  16   b  of the front frame  16 . The display plate  20  is colored black except for display marks, which will be discussed below. As shown in  FIG. 1 , a plurality of translucent display marks for displaying the vehicle driving state, such as a lamp illumination mark  20   a , a seatbelt reminder mark  20   b , a left blinker mark  20   c  and a right blinker mark  20   d , are assigned at positions corresponding to each of the light guiding portions  15   a  of the display plate  20 . A plurality of display light-emitting elements  21  are arranged at the front of the circuit board  17  so as to correspond to the light guiding portions  15   a  of the front case member  14   b . The display light-emitting elements  21  emit light, thereby displaying the display marks  20   a  to  20   d  on the display plate  20  in a standing out manner. The display marks  20   a  to  20   d  are invisible in the state where the display light-emitting elements  21  do not emit light. The front frame  16  is jet-black and thus, is almost invisible, and the boundary between the front frame  16  and the display plate  20  is also invisible. 
     As shown in  FIGS. 2 and 3 , in an outer lower portion of the light-emitting display unit  18 , a plurality of decorative (illumination) light-emitting elements  22  are horizontally arranged at the front of the circuit board  17 . An inclined portion  23  is formed at a lower end of the color filter  19 , and a light-discharging surface  23   a  for discharging light from the decorative light-emitting elements  22  is formed at the front of the inclined portion  23  so as extend in the horizontal direction. The light-discharging surface  23   a  is formed by roughening the front surface of the inclined portion  23 , for example, by applying fine grain finishing. 
     An inclined reflection portion  24  is formed at lower front end of the front case member  14   b  so as to be located in a light path from the decorative light-emitting elements  22  to the light-discharging surface  23   a . A reflecting surface  24   a  for reflecting light from the decorative light-emitting elements  22  and allowing the light to reach the light-discharging surface  23   a  is formed in the inner surface of the reflection portion  24 . The reflecting surface  24   a  is formed by applying mirror-like finishing such as metal evaporation and metal plating to the inner surface of the reflection portion  24 . A barrier portion  24   b  protrudes from an upper end of the reflection portion  24 , preventing excessive light from the decorative light-emitting elements  22  from leaking in the forward direction. 
     A wall portion  25  protruding downward is provided at a lower end of the color filter  19  so as to be connected to the inclined portion  23 . The existence of the wall portion  25  prevents light from the reflecting surface  24   a  from leaking to the back surface of the color filter  19 . 
     Next, operation of the vehicle meter device thus configured will be described. 
     During driving of the vehicle, the driving state is displayed through light emission of the displays  18   a  to  18   d  of the light-emitting display unit  18  and light emission of the display marks  20   a  to  20   d  by the display light-emitting elements  21 . In this case, display light of the light-emitting display unit  18  is converted into light of color that has less visual stimulus but is highly visible through the color filter  19 . In displaying the driving state, the decorative light-emitting elements  22  emit light, and the light is guided to the light-discharging surface  23   a  below the color filter  19  through the reflecting surface  24   a  and then, the decorative light is discharged from the light-discharging surface  23   a  in the forward direction. Therefore, the display device  12  can achieve an excellent decorative effect. 
     This embodiment achieves the following advantages. 
     (1) In this embodiment, the light-discharging surface  23   a  for discharging light from the decorative light-emitting elements  22  through the reflecting surface  24   a  in the forward direction is formed at the lower end of the color filter  19  arranged at the light-emitting display unit  18 . For this reason, the decorative effect of the display device  12  can be obtained by utilizing the color filter  19  for the light-emitting display unit  18 . Further, since the decorative light-emitting elements  22  can be used only for decorative illumination, not for display, a highly decorative effect can be obtained. 
     (2) In this embodiment, since the barrier portion  24   b  of the reflection portion  24  prevents excessive light from the light-emitting display unit  18  to leak in the forward direction, loss of the decorative effect can be prevented. 
     (3) In this embodiment, the reflecting surface  24   a  is formed in the light path of the decorative light-emitting elements  22 , and light from the decorative light-emitting elements  22  reaches the light-discharging surface  23   a  through the reflecting surface  24   a . For this reason, even when the decorative light-emitting elements  22  are located separately from the light-discharging surface  23   a , light from the decorative light-emitting elements  22  can be guided to the light-discharging surface  23   a  through the reflecting surface  24   a . Accordingly, since the decorative light-emitting elements  22  can be incorporated at positions where they cannot be viewed from the outside and they can be easily mounted, excellent appearance can be obtained and the whole of the device can be reduced in size. 
     (4) In this embodiment, the light-discharging surface  23   a  is formed by roughening the inclined portion  23  arranged at the end of the color filter  19 . For this reason, the light-discharging surface can be formed without greatly changing the configuration of the color filter  19 . 
     (5) In this embodiment, the reflecting surface  24   a  is provided in a portion of the front case member  14   b  of the display device  12 . For this reason, there is no need to arrange a dedicated reflection member having a reflecting surface in the light path of the decorative light-emitting elements  22 , which contributes to a simple configuration. 
     (6) In this embodiment, the color filter  19  is provided with the wall portion  25  for preventing light from the reflecting surface  24   a  from leaking to the back surface of the color filter  19 . For this reason, the light from the reflecting surface  24   a  is prevented from leaking to the back surface of the color filter  19 . This reduces the possibility that display unevenness due to shading or contrast occurs in display of the vehicle driving state by the light-emitting display unit  18 . 
     (7) In this embodiment, the color filter  19  and the front plate  13  are subjected to smoke processing. For this reason, undesirable parts of the meter device  10  in appearance, for example, structures such as printing pattern on the light-emitting display unit  18  and fastening screws are hidden, and the vehicle driving state can be clearly displayed. In contrast, when the front plate  13 , which is not subjected to smoke processing, is used, the smoke opacity lacks and thus, the undesirable parts in appearance are visually recognized. This problem can be addressed only by increasing the smoke opacity of the color filter. However, in this case, the function of the color filter is degraded and the display brightness of each of the displays  18   a  to  18   d  in the light-emitting display unit  18  cannot be ensured. This embodiment can avoid these problems. 
     Modifications 
     The embodiment may be modified as follows. 
     As shown in  FIG. 4 , the light-discharging surface  28   a  may be provided in a lower end surface of the color filter  19 , and the wall portion  25  may be omitted. 
     Although the light-discharging surface  23   a  is formed by roughening the inclined portion  23  of the color filter  19  in the embodiment, the light-discharging surface  23   a  may be formed by applying metal plating to the inclined portion  23  or adhering a reflective sheet to the inclined portion  23 . 
     Although the reflecting surface  24   a  is provided at a part of the front case member  14   b  of the display device  12  in this embodiment, the reflecting surface  24   a  may be provided at a part of a vehicle component such as the instrument panel  12 . 
     Although the reflecting surface  24   a  is provided at a part of the front case  15  in this embodiment, the reflecting surface  24   a  may be provided at the reflecting plate. 
     The front plate  13  that is not subjected to smoke processing may be used in the meter device  10 .