JP2004037535A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device in which faster temperature control is feasible. <P>SOLUTION: A display device utilizing light transmitted by a light emitting diode 5B for display is provided with: a first polarizing member 4B; a liquid crystal cell 4A with the first polarizing member 4B disposed on one surface side thereof; a translucent panel heater 4C with a heating surface placed opposite to the other surface side of the liquid crystal cell 4A; and a second polarizing member 4D disposed on the surface of the panel heater 4C opposite to the heating surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device that performs display using transmitted light from a light source.
[0002]
[Prior art]
Conventionally, there is a liquid crystal display device using a liquid crystal cell as a display device. This liquid crystal cell is configured by sealing liquid crystal between both electrode substrates, and performs display under driving by a driving device.
[0003]
In addition, in the liquid crystal display device, when the temperature of the liquid crystal is not within an appropriate operating temperature range, the operation of the liquid crystal deteriorates. For this reason, it is difficult to perform good display by the liquid crystal display device. In particular, when the temperature of the liquid crystal becomes lower than the temperature within an appropriate operating temperature range, the response of the liquid crystal sharply decreases due to the increase in the viscosity of the liquid crystal.
[0004]
Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. H11-38391, there is known one that controls the temperature of the liquid crystal to be within an appropriate operating temperature range. Such a display device uses a panel heater, a cooling fan, or the like to control the temperature of the liquid crystal within an appropriate operating temperature range by using a panel heater, a cooling fan, or the like in order to immediately perform good display after turning on a power switch. Is what you do.
[0005]
[Problems to be solved by the invention]
However, when the device is used in a severe environment where the temperature is intense, such as when mounted on a vehicle, an appropriate operating temperature range of the liquid crystal may be significantly different from the actual temperature of the liquid crystal. Temperature control was needed.
[0006]
In particular, in these temperature controls, when using a panel heater to raise the temperature of the liquid crystal to within an appropriate operating temperature range, it takes time to conduct heat from the panel heater to the liquid crystal. In addition, since the temperature is gradually increased at the heat generation temperature in consideration of the heat resistance temperature of various parts in contact with the heat generation portion of the panel heater, the temperature of the liquid crystal is raised to an appropriate temperature range for the liquid crystal in a very low temperature state. It took a long time to make it work. Therefore, during this time, it has been a problem because good display by the liquid crystal display device has been difficult.
[0007]
Accordingly, the present invention has been made in view of the above-described problem, and has as its object to provide a display device capable of performing more rapid temperature control.
[0008]
[Means for Solving the Problems]
As described in claim 1, the lighting device of the present invention includes a first polarizing member, a liquid crystal cell provided with the first polarizing member on one surface side, and the other surface side of the liquid crystal cell. Characterized by comprising a translucent panel heater having a heat-generating surface so as to face the panel, and a second polarizing member provided on the surface opposite to the heat-generating surface of the panel heater. .
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, taking a display device provided in a vehicular head-up display for displaying a vehicle speed, an engine speed, and the like as an example.
[0010]
FIG. 1 shows a vehicle head-up display mounted on a vehicle. A display image projected by a head-up display C provided on a dashboard B of a vehicle A is directed to a viewer E by a windshield D. It is a structure that is reflected by The observer E can observe the display image as a virtual image F by superimposing it on a landscape.
[0011]
The head-up display C according to the embodiment of the present invention includes a concave mirror 2, a liquid crystal display 3, and the like in a housing 1 provided so as to be embedded in an upper portion of a dashboard B. 2 will be described.
[0012]
The housing 1 is made of a light-shielding synthetic resin material, and has a first opening 1A that opens an upper part (front glass D side) of a position where the concave mirror 2 is provided, and a second opening 1B that projects a heat sink described later. Is provided, and a light-shielding wall 1C is provided in the housing 1 for preventing sunlight from being incident on the liquid crystal display 3 to make it difficult to see the virtual image F (washout). 1 and molded integrally. Further, a light-transmitting cover 1D made of a light-transmitting synthetic resin material (for example, acrylic) is provided on an upper portion of the housing 1, and is disposed so as to close the first opening 1A.
[0013]
The concave mirror 2 is provided in the housing 1 and reflects a display image projected from the liquid crystal display 3 toward the windshield D. The concave mirror 2 is provided so that the angle can be adjusted so that the observer E can easily view the displayed image.
[0014]
Hereinafter, the liquid crystal display 3 will be described with reference to FIGS.
[0015]
The liquid crystal display 3 projects a display image of the transmissive display element onto the windshield D via the concave mirror 2, and includes a liquid crystal display element (display device) 4, a wiring board 5, and a heat radiating member 6. ing. The liquid crystal display element 4 includes a calculation circuit for measuring a vehicle speed and an engine speed based on output signals from a vehicle speed sensor and an ignition coil provided in the vehicle A, and a liquid crystal drive circuit for driving the liquid crystal based on the calculation result. This is for expressing the measured values of the speed A and the engine speed as numerical values. The wiring board 5 has a light emitting diode 5B as a light source mounted on a hard wiring board 5A made of an insulating glass cloth base epoxy resin material so as to face the liquid crystal display element 4. The heat radiating member 6 is formed of a heat sink, is provided on the rear surface side of the wiring board 5, and is provided so as to face from the second opening 1B.
[0016]
According to the above configuration, the illumination light of the light emitting diode 5B illuminates the display image formed by the liquid crystal display element 4 so that the display indicating the vehicle state can be projected. A virtual image F can be displayed on the glass D.
[0017]
Further, the liquid crystal display element 4 which is a main part of the present invention will be described in detail with reference to FIG.
[0018]
As shown in FIG. 3, the liquid crystal display element 4 includes a liquid crystal cell 4A, a first polarizing member 4B, a panel heater 4C, and a second polarizing member 4D. The liquid crystal cell 4A is adhered at regular intervals so that two transparent substrates are parallel to each other, and a liquid crystal is sandwiched between the two transparent substrates. Pixel electrodes are provided in a matrix on the opposing surfaces of the two transparent substrates. On one transparent substrate, a TFT (thin film transistor) for switching the pixel electrodes and a voltage applied to the pixel electrodes are applied. An auxiliary capacitor or the like for holding is provided. The first polarizing member 4B is attached to the front side of the liquid crystal cell 4A (the output side of the display image). The panel heater 4C is provided at a predetermined interval on the back surface side of the liquid crystal cell 4A (incident side of the illumination light), and is provided on the surface of the translucent substrate 4E (on the surface facing the liquid crystal cell 4A) by ITO (Indium Tin Oxide). ) Is formed. The second polarizing member 4D is attached on the back surface of the transparent substrate 4E (the side surface on which the illumination light from the light emitting diode 5B is incident).
[0019]
The liquid crystal display element 4 includes a first polarizing member 4B, a liquid crystal cell 4A having the first polarizing member 4B provided on one surface side, and a heating surface facing the other surface side of the liquid crystal cell 4A. And a second polarizing member 4D provided on the surface opposite to the heat-generating surface of the panel heater 4C. Since the heat generating layer 4F and the liquid crystal cell 4A having a liquid crystal can be arranged close to each other, the liquid crystal cell can be efficiently warmed without an extra member. Therefore, the display device can perform more rapid temperature control on the liquid crystal.
[0020]
Further, since the light-transmitting heat generating layer 4F does not come into contact with other components (for example, the polarizing members 4B and 4D) other than the light-transmitting substrate 4E, the heat-generating layer 4F is heated to a higher temperature without considering the heat resistance temperature of the other components. Since heat can be generated, a large amount of heat can be transmitted to the liquid crystal in a short time. Therefore, the display device can perform more rapid temperature control on the liquid crystal.
[0021]
In the embodiment of the present invention, the heat generating surface of the panel heater 4C and the liquid crystal cell 4A are provided so as to be adjacent to each other at a predetermined interval. However, the present invention is not limited to this. Instead, the heating surface of the panel heater 4C and the surface of the liquid crystal cell 4A can be provided in contact with each other, and a greater effect can be expected.
[0022]
Further, in the embodiment of the present invention, a TFT type liquid crystal cell 4A having a thin film transistor has been described as an example. However, the present invention is not limited to this, and for example, an STN (Super Twisted Nematic) type. A liquid crystal cell may be used, and effects similar to those of the above-described embodiment can be obtained.
[0023]
【The invention's effect】
The display device of the present invention relates to a display device that performs display using transmitted light from a light source, and can perform more rapid temperature control.
[Brief description of the drawings]
FIG. 1 is a side view of a vehicle showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the head-up display showing the embodiment.
FIG. 3 is an essential part side view showing a part of the embodiment in a cross section;
[Explanation of symbols]
4A Liquid crystal cell 4B First polarizing member 4C Panel heater 4D Second polarizing member

Claims (1)

A first polarizing member, a liquid crystal cell provided with the first polarizing member on one surface side, and a translucent panel heater having a heating surface facing the other surface side of the liquid crystal cell. A second polarizing member provided on a surface side opposite to a heating surface of the panel heater.

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