JPS6331080Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display device used as a panel meter or other instruments installed in automobiles and the like.

In general, automotive instruments have operating temperature standards that require accurate operation within an environmental temperature range of -30 to 80 degrees Celsius. When using liquid crystals for instrument displays, the problem is driving at low temperatures, and the lower the temperature, the slower the response speed tends to be. For example, in the low temperature range around -30°C, the display takes more than 1 second to rise, and the response is too slow to meet usage standards. Furthermore, since the liquid crystal itself does not emit light by itself, illumination from the front or rear is required. A light emitting device, an incandescent lamp, a fluorescent lamp, or the like is used as a light source, and a fluorescent lamp is relatively preferable in terms of brightness, selection of emitted light color, and economy. However, fluorescent lamps also have the drawback that when the temperature reaches a low temperature range, the discharge gas condenses, resulting in poor light emission and a decrease in illumination power.

An object of the present invention is to provide a liquid crystal display device that satisfies the above-mentioned environmental conditions and eliminates the above-mentioned drawbacks.

The present invention will be described in detail below with reference to the illustrated embodiments. Reference numeral 1 denotes a box-shaped case, and a transparent protective cover 2 is attached to the front surface of the case. A liquid crystal display panel 3 is disposed approximately in the middle of such a case, that is, at a fitting portion between the case and the protective cover, and the interior is divided into a front display chamber 4 and a rear light source chamber 5.

The liquid crystal display board 3 has various display sections 3a, 3b, 3.
The display section 3a is a graphical or graphical display, and the display sections 3b and 3c are numerical displays. In addition to these displays, a plurality of circulation holes 6 are formed at appropriate intervals in the lower part of the liquid crystal display panel 3 to communicate the front display chamber 4 and the back light source chamber 5.

In the back light source chamber 5, a fluorescent lamp 7 for backlighting is attached to a back wall 8, and the back wall is made up of, for example, a printed circuit board on which a circuit for driving the liquid crystal display panel 3 is provided. and the liquid crystal display board are electrically connected at a plurality of locations on the side surfaces by flexible conductive tapes 9, 10, etc.

Duct 1 is located on the top of case 1 and protective cover 2.
1 is provided to communicate the front display chamber 4 and the rear light source chamber 5, and a fan 12 for circulating hot air driven by a motor is installed in the duct, and a fan 12 for generating hot air is installed near the opening of the duct. heater 1
3 is installed. This heater may be mounted at any position or condition where the air circulated by the fan 12 is heated. Further, the power supplies for driving the fan 12 and the heater 13 are connected to a circuit completely different from that of the liquid crystal display, so that their driving can be freely selected.

In a liquid crystal display device configured in this way, when driving a car in winter or in a cold region,
Turn on the drive switches for the fan 12 and heater 13 together with the instrument drive switch, and use the fan 12 to move between the front display chamber 4 and the rear light source chamber 5 via the circulation hole 6 and the duct 11 in the direction of arrow a. Air circulates as shown. During this circulation, the air is heated by the heater 13, and the warm air is circulated, so that the liquid crystal display panel 3 and the fluorescent lamp 7, which is the light source, are heated to an appropriate temperature. In order to prevent overheating, for example, a thermostat or the like may be installed that turns off the current supply circuit to the heater 13 when the temperature exceeds a predetermined temperature.

As explained above, the liquid crystal display device according to the present invention is equipped with a hot air circulation means consisting of a heater and a fan, and when used in a low temperature range, by driving the heater and fan, the liquid crystal display panel and fluorescent lamp can be removed. is heated to a predetermined temperature, and in the case of a liquid crystal display panel, the start-up operation of the display is performed quickly without any delay in response speed, and in the case of fluorescent lamps, there is no condensation of the discharge gas, and It has the effect of not turning off or reducing illuminance, and complies with temperature standards for environmental conditions as a display device for automobile instruments. Furthermore, since it is a closed circulation type, dust from the outside does not enter, and the internal mechanism is not contaminated, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a liquid crystal display device according to the present invention, and FIG. 2 is a side view showing a main part of the device in cross section. 1... Case, 2... Protective cover, 3... Liquid crystal display board, 4... Front display chamber, 5... Rear light source chamber,
6... Circulation hole, 7... Fluorescent lamp, 8... Rear wall (printed circuit board), 9, 10... Flexible conductive tape, 11... Duct, 12... Fan, 13...
…heater.

Claims (1)

[Scope of utility model registration request] A liquid crystal display panel is placed approximately in the middle of the case with a transparent protective cover attached to the front, dividing it into a front display chamber and a rear light source chamber.A fluorescent lamp for back illumination is attached to the rear light source chamber, and the liquid crystal display is divided into a front display chamber and a rear light source chamber. A plurality of circulation holes are provided at appropriate intervals in the lower part of the plate, a duct is installed on the top surface of the case to communicate the front display chamber and the rear light source chamber, and a fan is installed in the duct to circulate air. A liquid crystal display device characterized in that a heater is provided at a position where the liquid crystal display device is heated.