JPH0417973Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a structure for changing the brightness of daytime and nighttime illumination in a display device, for example, a display device for a vehicle-mounted device.

[Prior Art] Conventionally, as a display device, there is a display section of a vehicle air conditioner as shown in FIG. 4, for example. In the figure, a display panel 1 is a transmissive liquid crystal panel, and displays a display according to an electric signal sent from a vehicle air conditioner main body (not shown). And lighting lamp 2
The light emitted from the display panel 1 is uniformly guided throughout the display panel 1 by a light guide 3 made of a transparent resin such as acrylic, so that the occupant can visually recognize the display.

By the way, in general, in display devices for in-vehicle equipment that have a light-emitting display section, if the brightness of the display section's illumination is made bright enough to be visible even during the day when the surroundings are bright, it will be too bright and dazzling at night; If the brightness is set to an appropriate level, it will be too dark to see during the day, so the lamp that illuminates the display section of the display device (illumination lamp 2) must be replaced with a night light switch (not shown) to turn on the headlight, etc. When the night light switch is off, the display part (display panel 1) is illuminated so brightly that it can be seen even during the day, and when it is on, the display part (display panel 1) is illuminated so darkly that it is not dazzling even at night.

[Problem that the invention aims to solve] However, as mentioned above, it is difficult to
If one lamp were used to illuminate the display panel brightly during the day and darkly at night, the color of the light illuminated at night would be more reddish than the color of the light illuminated during the day, which was not desirable in terms of the design of the display panel.

[Means for Solving the Problems] In order to solve the above problems, the display device of the present invention includes a display panel for displaying the operating status of equipment, and a daytime lighting device for illuminating the display panel during the daytime. a lamp, a night illumination lamp for illuminating the display panel at nighttime darker than during the daytime, and light from the daytime illumination lamp and the nighttime illumination lamp is uniformly applied to the display panel from the back side of the display panel. and a light guide for guiding the illumination.

Furthermore, in the display device of the present invention, the light guide has a light emitting surface that has approximately the same area as the display panel and faces the display panel, and a light emitting surface that is provided at approximately the center of the surface that faces the light emitting surface for night illumination. a lamp accommodating recess, a reflecting surface for guiding light from the night illumination lamp in the left-right direction, which is provided at a position opposite to the night illumination lamp accommodating recess on the light exit surface side, and the night illumination lamp accommodating recess. daytime lighting lamp housing recesses provided at two locations on the left and right sides of the lamp.

[Function/Effect] According to the display device of the present invention as described above, by lighting the two daytime lighting lamps during the day, the display panel can be illuminated sufficiently brightly to the extent that it can be seen. By turning on only one night lighting lamp, the brightness is not dazzling (sufficient brightness compared to the brightness of daytime lighting).
can illuminate the display panel. Furthermore, since the shape of the light guide and the arrangement of the illumination lamps are configured as described above, the display panel can be uniformly illuminated both during the day and at night.

In addition, since the display panel is illuminated by different lamps during the day and at night, by changing the type of lamp for daytime and nighttime use, it is possible to easily solve the problem that the color of illumination light at night becomes reddish. I can do it.

[Examples] Specific examples of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a vehicle air conditioner according to the present invention, and the front of the device is provided with a transmissive liquid crystal panel 10 as a display panel for displaying operating status and a switch knob 40 for switching the device. . Inside the device, two printed circuit boards 52 and 54 on which electrical elements such as resistors and capacitors are arranged and electrical wiring patterns are formed are fixed to a housing 60. The first printed circuit board 52 includes a switch body 42 that is switched by a switch knob 40 and a light guide 30 that has fixing parts 38 at both ends.
is fixed, and the light guide 30 is located on the back side of the liquid crystal panel 10. Further, the back side of the light guide 30 (the side not facing the liquid crystal plate 10) faces the second printed circuit board 54 through a through hole 53 provided in the first printed circuit board 52.

A characteristic feature of the present invention is that the second printed circuit board 54 includes two daytime lighting lamps 22, 2.
2 and one night lighting lamp 24 are fixed, and the daytime lighting lamps 22, 22 are connected to the light guide 30.
The lamp 24 for night illumination is housed in the lamp housing recess 32 for daytime illumination 32 of the light guide 30 .

The daytime lighting lamps 22, 22 and the nighttime lighting lamp 24 are connected as shown in FIG.
When the night light switch 72 of the night light device 70 is off (the state shown in FIG. 2), the resistor R3,
Since current flows through the transistor Tr and the resistor R2, the transistor Tr is activated and the daytime lighting lamp 22 is connected from the power supply B through the resistor R3 and the transistor Tr.
22, and the daytime illumination lamps 22, 22 are turned on.

On the other hand, the night light switch 7 of the night light device 70
2 is on, current flows from the power supply B to the night illumination lamp 24 via the resistor R1 and the night illumination device 70, and the night illumination lamp 24 lights up.
Resistor from the night illumination device 70 via diode D
Since current also flows through R2 and voltage is applied to the base of the transistor Tr, the transistor Tr does not operate and the daytime illumination lamps 22, 22 do not light up. Therefore, in the liquid crystal panel 10, the relatively bright daytime illumination lamps 22, 22 are not turned on during the daytime. Therefore, the liquid crystal plate 10 is illuminated by the relatively bright daytime illumination lamps 22, 22 during the day, and is illuminated by the relatively dark nighttime illumination lamp 24 at night.

Furthermore, in the present invention, the light guide 30 has fixing parts 38 at both ends for fixing it to the first printed circuit board 52, as shown in FIG. It has a shape that widens at the end. The light guide 30 of the present invention is characterized by a light emitting surface 36 facing the liquid crystal plate 10, a night illumination lamp accommodating recess 34 provided approximately at the center of the surface opposite to the light emitting surface 36, and a light emitting surface 36. Reflective surfaces 37, 37 provided on the surface 36 at positions opposite to the night lighting lamp accommodating recess 34, and daytime lighting lamp accommodating recesses 32 provided at two locations on the left and right sides of the night lighting lamp accommodating recess 34. ,3
2. According to such a light guide, since there is one lamp storage recess 34 for night lighting and two lamp storage recesses 32, 32 for daytime lighting, the difference in brightness between nighttime and daytime lighting can be greatly reduced. can do. Furthermore, since the light from the night lighting lamp is distributed to the left and right by the reflective surfaces 37, 37, and the light from the daytime lighting lamp is emitted from two places, the liquid crystal panel 10 is uniformly illuminated both at night and during the day. be able to.

In addition, although the case where a liquid crystal board was used as a display panel was explained in this Example, this invention is not limited to these in any way, but can be applied to any display board that is illuminated from the back side. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a display device for an on-vehicle device according to the present invention, in which FIG. 1 a is a front view, FIG. An electrical circuit diagram for switching between the daytime lighting lamp and the nighttime lighting lamp of the device, FIG. 3 is a diagram of the light guide used in the present invention, FIG. 3a is a rear view,
3b is a plan view, FIG. 3c is a sectional view taken from FIG. 3a, FIG. 3d is a side view, and FIG. 4 is an exploded perspective view showing the main parts of a conventional display device. 1, 10...display panel (liquid crystal board), 22...
Daytime lighting lamp, 24...Night lighting lamp,
30...Light guide.

Claims (1)

[Claims for Utility Model Registration] A display panel for displaying the operating status of equipment, a daytime illumination lamp for illuminating the display panel during the day, and a lamp for illuminating the display panel darker than during the day at night. A display device comprising: a nighttime lighting lamp; and a light guide that guides light from the daytime lighting lamp and the nighttime lighting lamp so as to uniformly illuminate the display panel from the back surface of the display panel. The conductor has a light emitting surface facing the display panel and having approximately the same area as the display panel, a night illumination lamp accommodating recess provided approximately at the center of the surface facing the light emitting surface, and a recess on the side of the light emitting surface. a reflective surface for guiding light from the night-light lamp in the left-right direction, which is provided at a position opposite to the night-light lamp-accommodating recess; A display device comprising: a recess for accommodating a daytime lighting lamp;