JP3387247B2 - LCD display - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display suitable for displaying, for example, pressure, speed, current and the like in vehicles, ships, aircrafts, and the like. 2. Description of the Related Art Conventionally, liquid crystal displays have been used as meters for vehicles and the like. A conventional liquid crystal display uses a halogen lamp or a cold cathode tube as a backlight, arranges a color filter between the liquid crystal display section and the backlight light source, and emits light of a color corresponding to the transmitted light wavelength of the color filter. Was displayed. The display colors are considered to be beautiful and have good visibility, with emphasis on vehicle design and the like. [0003] Since a conventional liquid crystal display uses a halogen lamp or a cold cathode tube as a backlight, the wavelength of the light contained in the backlight is constant over a wide range or has many peaks. Therefore, a beautiful color with good visibility can be realized only by slightly changing the color of the color filter. [0004] Liquid crystal displays used in commercial vehicles and ships are required to have a long life light source that can withstand continuous operation, rather than beautiful colors. Therefore, it has been considered to use a light emitting diode (LED) as a backlight instead of a halogen lamp or a cold cathode tube. [0005] However, for example, in a railway vehicle, the display pressure is required to simultaneously check the outlet pressure of the air compressor and the outlet pressure of the regulator, or to simultaneously check the pressure of the reservoir tank of the compressed air and the cylinder pressure of the air brake. A liquid crystal display having a plurality of liquid crystal display units having different colors is used. When a light emitting diode is used as a backlight light source in such a liquid crystal display, the light emitting diode has a narrow half-width of an emission wavelength, and therefore, the liquid crystal display portion of a display color corresponding to the emission wavelength can be brightened. There is a problem that the liquid crystal display portion of the display color becomes dark. An object of the present invention is to provide a liquid crystal display capable of solving the above problems. The liquid crystal display of the present invention comprises:
A plurality of liquid crystal display portions having different display colors are illuminated by light emitting diodes having an emission wavelength corresponding to the display color via a color filter that transmits light having a wavelength corresponding to the display color, and each color filter is It is characterized by transmitting a part of the wavelength light of the display color of each liquid crystal display part and reflecting a part thereof. For example, in the case where the liquid crystal display section has a fixed color arrangement pattern and displays two colors, one of the liquid crystal display sections is passed through a color filter which transmits the wavelength light of one display color, and the wavelength of light of one display color is transmitted. The other liquid crystal display unit is illuminated from the back with a light emitting diode emitting wavelength light of the other display color through a color filter transmitting the wavelength light of the other display color. The corresponding color filter and light emitting diode are
Since the transmission wavelength and the emission wavelength do not need to completely match, and it is difficult to make them completely match in practice, the configuration of the color filter according to the emission wavelength of the light emitting diode is to be as close as possible. A dye may be selected. According to the liquid crystal display of the present invention, the color filter that transmits light having the wavelength corresponding to the display color of each liquid crystal display section is formed by a light emitting diode having a wavelength corresponding to each display color. Light from the light-emitting diodes with different wavelengths from the display colors, so that the light from the light-emitting diodes with the wavelengths corresponding to the display colors in each liquid crystal display section is selected by wavelength selection. It becomes bright light,
It is possible to prevent the occurrence of uneven brightness due to light from the light emitting diode having a wavelength different from each display color, and to make the display brightness uniform. Thereby, each liquid crystal display unit can be brightly illuminated with light from the light emitting diode having a wavelength corresponding to each display color, the backlight can have a long life, and the display colors can be beautiful and have good visibility. Furthermore, since each color filter transmits a part of the wavelength light of the display color of each liquid crystal display part and reflects a part thereof, when light from the outside of the liquid crystal display irradiates the liquid crystal display part, the display color is changed. External light other than the light having the wavelength of passes through the color filter, and the external light having the wavelength of the display color can be reflected and scattered by the color filter. Therefore, the display on the liquid crystal display unit can be easily visually recognized even in a place where direct sunlight is applied. Embodiments of the present invention will be described below with reference to the drawings. The liquid crystal display 1 shown in FIGS. 1 and 2 is mounted on a railway car and has different pressures such as an outlet pressure of an air compressor and an outlet pressure of a regulator, a pressure of a reservoir tank of compressed air, a cylinder pressure of an air brake, and the like. 7 is a fixed segment display pressure gauge used to indicate two pressures. This liquid crystal display 1 has two concentrically arranged liquid crystal displays.
Liquid crystal display unit 2 composed of a plurality of fixed segments 2 arranged on the display panel 3 along each of the two arcs
A and 2B, one liquid crystal display 2A along one arc displays one pressure value, and the other liquid crystal display 2B along the other arc displays the other pressure value. The number of segments 2 forming one liquid crystal display 2A and the number of segments 2 forming the other liquid crystal display 2B are the same, and correspond to the same pressure value in one liquid crystal display 2A and the other liquid crystal display 2B. The segments 2 are arranged to face each other in the radial direction. On the display panel 3, two digital liquid crystal display units 4A and 4B composed of 7 segments 4 are provided, and digitally display the pressure values displayed by the liquid crystal display units 2A and 2B along each arc. A substrate 6 and a liquid crystal driver 14 constituting the liquid crystal driving device are built in a housing 11 of the liquid crystal display 1. As shown in FIG.
A / D converter 12 and a microcomputer 13 are formed. The analog current signal corresponding to the measured pressure sent from the pressure sensor 15 is subjected to I / V conversion and A / D conversion by the A / D converter 12 to be converted into a digital voltage signal. The microcomputer 13 performs an operation based on the digital voltage signal to determine a display, and sends a control signal to the driver circuit 14. In response to the control signal, the driver circuit 14 controls the liquid crystal display units 2A, 2B, 4
A drive signal is sent to the electrodes formed in segments 2 and 4 of A and 4B. The segments 2 and 4 are turned on and off by the drive signal. As a result, the liquid crystal of the segment corresponding to the measured pressure is turned off to transmit light, the remaining liquid crystal is turned on to transmit no light, and the measured pressure value is displayed. A backlight source for illuminating the liquid crystal display units 2A, 2B, 4A and 4B from the back is built in the housing 11. The backlight light source is constituted by a plurality of light emitting diodes 21A and 21B, and is arranged on the substrate 20 so as to face the rear surfaces of the liquid crystal display units 2A, 2B, 4A and 4B. In this embodiment, the light emitting diode 21A that illuminates the liquid crystal display unit 2A along one arc and the digital liquid crystal display unit 4A corresponding to the liquid crystal display unit 2A has an emission wavelength of green, and the liquid crystal along the other arc. Display 2B
Then, the light emitting wavelength of the light emitting diode 21B for illuminating the digital liquid crystal display unit 4B corresponding to the liquid crystal display unit 2B is amber. In a liquid crystal display section 2A along one arc and a digital liquid crystal display section 4A corresponding to the liquid crystal display section 2A (a region surrounded by a virtual line in FIG. 2), a green color is formed on the back surface of the display panel 3. A color filter 25A that transmits light of a wavelength is attached. In addition, in the liquid crystal display portion 2B along the other arc and the formation region of the digital liquid crystal display portion 4B corresponding to the liquid crystal display portion 2B (the region surrounded by the virtual line in FIG. 2), the back surface of the display panel 3 has an amber color. A color filter 25B that transmits light of a wavelength is attached. Thus, each of the liquid crystal display units 2A, 2B, 4A, 4
B is illuminated by light-emitting diodes 21A and 21B having emission wavelengths corresponding to the display color via color filters 25A and 25B that transmit light having a wavelength corresponding to the display color, and a liquid crystal display section along one arc. 2A and a digital liquid crystal display 4A corresponding to the liquid crystal display 2A have a display color of green, a liquid crystal display 2B along the other arc, and a digital liquid crystal display 4B corresponding to the liquid crystal display 2B. Means that the display color is amber. Furthermore, each color filter 25A, 25
B is a semi-reflective type, and one color filter 25A transmits a part of the green wavelength light and reflects and scatters a part of it, and the other color filter 25B transmits a part of the amber wavelength light. Along with it, it reflects and scatters a part.
Thus, when light from the outside of the liquid crystal display 1 irradiates the liquid crystal display units 2A, 2B, 4A, and 4B, external light other than the wavelength of the display color is applied to the color filters 25A and 25B in the off segments 2 and 4. And the external light having the wavelength of the display color is reflected and scattered by the color filters 25A and 25B. Therefore, the display of the liquid crystal display units 2A, 2B, 4A, and 4B can be easily visually recognized even in a place exposed to direct sunlight. According to the liquid crystal display 1, the color filters 25A and 25B transmitting the wavelength light corresponding to the display colors of the liquid crystal display units 2A, 2B, 4A and 4B emit light of the wavelength corresponding to each display color. Only the light from the diodes 21A and 21B is transmitted, and the transmission of light from the light emitting diodes 21A and 21B having a wavelength different from each display color is prevented. The light from the light emitting diodes 21A and 21B having a wavelength corresponding to the above becomes vivid light by the wavelength selection, and it is possible to prevent the occurrence of uneven brightness due to the light from the light emitting diodes 21A and 21B having a wavelength different from each display color, The display brightness can be made uniform. Thus, each of the liquid crystal display units 2A, 2B, 4A, 4
B can be brightly illuminated by light from the light emitting diode having a wavelength corresponding to each display color, so that the backlight has a long life,
In addition, the color of the display can be made beautiful and highly visible. Moreover, since the color filters 25A and 25B are of a semi-reflective type, the display of the liquid crystal display units 2A, 2B, 4A and 4B can be easily visually recognized even in a place where direct sunlight is applied. The present invention is not limited to the above embodiment. For example, the present invention can be applied to other instruments and indicators that display values other than pressure. Further, although the liquid crystal display section has a fixed segment display, it may be a dot matrix display. The display color of the liquid crystal display is not limited to green or amber, and may be three or more colors. The color filter may be of a transmissive type instead of a semi-reflective type. Each color filter preferably transmits a part of the wavelength light of the display color of each liquid crystal display part and reflects a part of the light. Thus, when light from the outside of the liquid crystal display irradiates the liquid crystal display unit, external light other than the display color wavelength light passes through the color filter, and the external light of the display color wavelength is reflected by the color filter. It becomes possible to scatter. Therefore, the display on the liquid crystal display unit can be easily visually recognized even in a place where direct sunlight is applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a liquid crystal display according to an embodiment of the present invention in a partially broken state. FIG. 2 is a front view of a display unit of the liquid crystal display. FIG. Block diagram for explaining the configuration of the display [Description of reference numerals] 1 Liquid crystal display 2A, 2B, 4A, 4B Liquid crystal display 21A, 21B Light emitting diode 25A, 25B Color filter

Claims (1)

(57) [Claims 1] A plurality of liquid crystal display units having different display colors emit light of a wavelength corresponding to the display color by light emitting diodes having an emission wavelength corresponding to the display color. A liquid crystal display, which is illuminated through a transmitting color filter, wherein each color filter transmits a part of the wavelength light of the display color of each liquid crystal display unit and reflects a part thereof.