JP3613867B2 - Display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a display device suitable for a head-up display device used for vehicles such as vehicles such as automobiles, ships, and aircraft.
[0002]
[Prior art]
For example, a head-up display device (HUD) for an automobile can be used as a terminal for displaying car navigation information, so that route information can be obtained while looking forward while driving.
[0003]
Such a head-up display device includes an image display light beam emitting device, and a combiner that changes the optical path to guide the image display light beam to the observer's visual field and transmits the light beam from the observer's front visual field. Prepare.
[0004]
Conventionally, as the image display light beam emitting device, a device that emits a fixed pattern image display light beam using a VFD (fluorescent display tube) capable of obtaining sufficient display brightness has been mainly used. An apparatus has been proposed that emits image display light of various patterns using a dot matrix liquid crystal display and a backlight.
[0005]
[Problems to be solved by the invention]
The dot matrix liquid crystal display includes a simple matrix type in which the liquid crystal of each pixel is directly driven from a scanning electrode and an active matrix type having a switching element such as a TFT corresponding to each pixel.
[0006]
In a simple matrix type liquid crystal display, an STN mode is generally used as a liquid crystal operation mode. However, when performing color display in the STN mode, there is a problem in that the structure becomes complicated because it is necessary to use a D-STN (Double Layered-STN) mode in which reverse twisted STN for optical phase compensation is stacked. In addition, since a simple matrix type liquid crystal display has a slow response speed when switching display images, it is not possible to immediately display an information image clearly.
[0007]
An active matrix liquid crystal display has a low aperture ratio because a switching element such as a TFT needs to be provided on the display panel. For this reason, when a color filter is stacked on a display panel to perform color display, the light transmittance as a whole is as low as about 5%, coupled with the low transmittance of the color filter. Therefore, in order to ensure sufficient display brightness as a head-up display device, an LED light source with a small amount of heat cannot be used due to insufficient light amount, and a high-power light source is required and the amount of heat generated is enormous. It is not practical. Further, since switching elements such as TFTs are provided corresponding to the respective pixels, the cost increases.
[0008]
It is an object of the present invention to provide a display device that can solve the above problems.
[0009]
[Means for Solving the Problems]
The present invention, in a display device comprising an image display light beam emitting device, and a combiner that changes the optical path of the image display light beam and guides it to the viewer's field of view, and transmits light from the viewer's front field of view, The image display beam emitting device includes a transmission-type monochrome simple matrix liquid crystal display whose liquid crystal operation mode is a BTN (bistable twisted nematic) mode, and a backlight device capable of changing the emission wavelength peak of irradiation light of the liquid crystal display And means capable of synchronizing the image display timing of the liquid crystal display and the light emission timing due to a desired light emission wavelength peak of the backlight device.
[0010]
According to the configuration of the present invention, a plurality of images constituting one piece of information are repeatedly displayed on a liquid crystal display in a time-sharing manner, and the display timing of the display image is synchronized with the emission timing due to a desired emission wavelength peak of the backlight device. By doing so, it is possible to make the observer recognize that one piece of information as a multicolor image without using a color filter. In addition, the liquid crystal operation mode of the liquid crystal display is a BTN mode that utilizes the fact that liquid crystal molecules maintain a constant arrangement at two twist angles for several seconds, so that switching of images can be performed without using a switching element such as a TFT. It can be performed at high speed, and time division display of a plurality of images, which is impossible in the D-STN mode, becomes possible.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 shows a display device 1 that constitutes a vehicle head-up display device. The display device 1 emits an image display light beam L1 built in a housing 2 such as a dashboard of the vehicle, and is provided on the housing 2. It is provided with a combiner 4 and is used as a terminal for displaying car navigation information.
[0013]
The combiner 4 changes the optical path of the image display light beam L1 to guide the observer A's visual field, and transmits the light beam L2 from the front visual field of the observer A that passes through the windshield 5 of the vehicle. Thereby, the observer A can visually recognize the virtual image and the actual scenery formed in the far distance by the image display light beam L1.
The combiner 4 is not limited to be coaxial with the optical path of the image display light beam L1 before and after the change, and may be any device that can transmit the light beam L2 from the front field of view of the observer A. A half mirror that reflects the light beam L1 or a diffracting hologram element can be used. Note that another optical system such as a mirror may be interposed between the emission device 3 and the combiner 4.
[0014]
As shown in FIG. 2, the emission device 3 includes a transmission-type monochrome simple matrix liquid crystal display 11, a backlight device 12 capable of changing the wavelength of light emitted from the liquid crystal display 11, the liquid crystal display 11 and the backlight. And a control device 13 of the device 12.
[0015]
The liquid crystal operation mode of the liquid crystal display 11 is a BTN mode that utilizes the fact that liquid crystal molecules maintain a constant alignment at two twist angles for several seconds. By directly driving the liquid crystal of each pixel from each scan electrode, Each pixel can be switched between a light transmission state and a non-transmission state.
[0016]
The backlight device 12 includes an LED array 22 formed on the substrate 21 as a light source, and a scattering plate 23 that scatters the emitted light of the LED array 22 so that the entire display surface of the liquid crystal display 11 can be uniformly irradiated. Have. The LED array 22 is configured by forming three types of LEDs 22 r, 22 g, and 22 b having different emission wavelength peaks so as to be uniformly distributed on the substrate 21. In the present embodiment, the colors corresponding to the emission wavelength peaks of the respective types of LEDs 22r, 22g, and 22b are the three primary colors of red, green, and blue.
[0017]
The control device 13 can synchronize the image display timing of the liquid crystal display 11 and the light emission timing due to the desired light emission wavelength peak of the backlight device 12, and includes a liquid crystal driver 31, a backlight driver 32, and both drivers. 31 and 32, a control computer 33, a memory 34 connected to the driver control computer 33, a navigation information determination computer 35 connected to the computer 22 and the memory 34, and a computer 35. And a GPS sensor 36.
[0018]
The GPS sensor 36 sends a signal from an artificial satellite constituting a GPS (Global Positioning System) to the navigation information determination computer 35.
[0019]
The navigation information determination computer 35 determines specific data for each of the red, green and blue images constituting the navigation information based on the signal from the artificial satellite and the stored program, and stores it in the memory 34. A display instruction signal is generated based on the display order of each data, display time, etc., and sent to the driver control computer 33.
[0020]
The memory 34 has a red image data storage area 34r, a green image data storage area 34g, and a blue image data storage area 34b.
[0021]
The driver control computer 33 reads the image specifying data from each of the storage areas 34r, 34g, 34b of the memory 34 by the display instruction signal, and the control signal corresponding to the shape of the image specified by the image specifying data to the liquid crystal driver 31. And a control signal corresponding to the color of the image specified by the image specifying data to the backlight driver 32 in synchronization with the control signal.
[0022]
The liquid crystal driver 31 sends a liquid crystal drive signal for each pixel of the liquid crystal display 11.
[0023]
The backlight driver 32 sends light emission drive signals for the LEDs 22 r, 22 g, and 22 b to the backlight device 12.
[0024]
3 (1), (2), (3), and FIG. 4 show examples of right-turn display by the display device 1. FIG.
[0025]
First, the navigation information decision computer 35 decides to perform a right turn display based on a signal from the GPS sensor 36, and stores the image data corresponding to the circular area in the red image data storage area 34r of the memory 34, so that the green color is displayed. The image data corresponding to the right turn instruction arrow is stored in the image data storage area 34g and the blue image data storage area 34b. Also, the red image data is first displayed for a predetermined unit time, then the right turn instruction arrow is displayed for twice the time of the red image data, and it is decided to repeat the display, and the display corresponding to the decision An instruction signal is generated and sent to the driver control computer 33.
[0026]
Thereby, the driver control computer 33 first reads out the image specifying data from the red image data storage area 34r of the memory 34 by the display instruction signal, and sends a control signal corresponding to the shape of the circular image to the liquid crystal driver 31. At the same time, a control signal corresponding to red is sent to the backlight driver 32 in synchronization with the control signal.
[0027]
The liquid crystal driver 31 sends a drive signal so that a pixel in a light transmission state and a pixel in a non-transmission state are formed so that a circular image can be displayed on the liquid crystal display 11. Thereby, as shown in (1) of FIG. 3, in the liquid crystal display 11, the pixels constituting the circular image 11 a are in a light transmissive state, and the other pixels are in a light non-transmissive state. Further, the backlight driver 32 sends a drive signal for causing the backlight device 12 to emit light from the LED 22r having an emission wavelength peak corresponding to red. Thereby, in synchronization with the display timing of the circular image of the liquid crystal display 11, the LED 22r having the emission wavelength peak corresponding to red of the backlight device 12 is turned on, and the LED 22g having the emission wavelength peak corresponding to green and blue is turned on. 22b is turned off.
[0028]
Next, the driver control computer 33 reads out the image specifying data from the blue image data storage area 34b of the memory 34 by the display instruction signal, and sends a control signal corresponding to the shape of the right turn arrow image to the liquid crystal driver 31. In synchronization with the control signal, a control signal corresponding to blue is sent to the backlight driver 32. The liquid crystal driver 31 sends a drive signal so that pixels that are in a light transmissive state and pixels that are in a non-transmissive state are formed so that a right-turn arrow image can be displayed on the liquid crystal display 11. As a result, as shown in (2) of FIG. 3, in the liquid crystal display 11, the pixels constituting the right turn instruction arrow image 11b are in a light transmissive state, and the other pixels are in a light non-transmissive state. . In synchronization with the display timing of the right turn instruction arrow image on the liquid crystal display 11, the light emission wavelength peak LED 22b corresponding to the blue color of the backlight device 12 is turned on, and the light emission wavelength peak LEDs 22r and 22g corresponding to red and green light. Is turned off.
[0029]
Next, the driver control computer 33 reads the image specifying data from the storage area 34g of the green image data in the memory 34 according to the display instruction signal, and sends a control signal corresponding to the shape of the right turn arrow image to the liquid crystal driver 31. In synchronization with the control signal, a control signal corresponding to green is sent to the backlight driver 32. The liquid crystal driver 31 sends a drive signal so that pixels that are in a light transmissive state and pixels that are in a non-transmissive state are formed so that a right-turn arrow image can be displayed on the liquid crystal display 11. As a result, as shown in FIG. 3 (3), the pixels constituting the right turn instruction arrow image 11b in the liquid crystal display 11 are continuously set to the light transmitting state, and the other pixels are set to the light non-transmitting state. Is done. In synchronization with the display timing of the right turn instruction arrow image on the liquid crystal display 11, the LED 22g of the emission wavelength peak corresponding to green of the backlight device 12 is turned on, and the LEDs 22r and 22b of emission wavelength peaks corresponding to red and blue are turned on. Is turned off.
[0030]
The images shown in (1) to (3) of FIG. 3 are repeatedly displayed in a time-sharing manner, and the display timing of the light emission wavelength peak of the desired color in the LEDs 22r, 22g, 22b of the backlight device 12 is displayed. The light emission timing is synchronized. As a result, as shown in FIG. 4, the viewer A visually recognizes that the red circular image R has the white right turn instruction arrow image W.
[0031]
According to the above configuration, a plurality of images 11a and 11b constituting one information are repeatedly displayed on the liquid crystal display 11 in a time-sharing manner, and the display timing of the display images 11a and 11b and a desired emission wavelength peak of the backlight device 12 are displayed. By synchronizing with the light emission timing by, the observer A can recognize the one piece of information as multicolor images R and W without using a color filter. The liquid crystal operation mode of the liquid crystal display 11 is a BTN mode that utilizes the fact that liquid crystal molecules maintain a constant alignment at two twist angles for several seconds, so that switching of images without using a switching element such as a TFT is possible. The time division display of a plurality of images, which is impossible in the D-STN mode, becomes possible.
[0032]
In addition, this invention is not limited to the said embodiment. For example, the emission wavelength peak of the light emitted from the liquid crystal display by the backlight device is not limited to those corresponding to the three primary colors, but may correspond to other colors, and may correspond to two colors or four or more colors. It is sufficient that the light can be emitted with at least two types of wavelength peaks. Further, the content of the display image is not limited to that corresponding to the navigation information, and can be any content. In addition, the use of the display device of the present invention is not limited to a head-up display device mounted on an automobile, for example, a head-up mounted on another vehicle, motorcycle, ship, aircraft, etc. that require clear information outdoors. It can also be used as a display device. Further, instead of the driver control computer 33, a programmable logic device (PLD) that can be written and erased may be used. In addition, the plurality of types of LEDs serving as the light source of the backlight device are not limited to those that are uniformly distributed and arranged, but are arranged in a certain pattern according to the display image, and the LEDs of each pattern are controlled by independent circuits. May be. Further, the light source is not limited to the LED, and any light source having a relatively small calorific value can be used.
[0033]
【The invention's effect】
According to the display device of the present invention, it is possible to perform color display without using a color filter and it is not necessary to provide a switching element for driving a liquid crystal. Even if a small amount of LED light source or the like is used, sufficient display luminance can be secured. Further, since it is not necessary to provide a switching element for driving liquid crystal corresponding to each pixel, the cost can be reduced. Furthermore, since the images can be switched at high speed, the information image can be displayed clearly and the eyestrain of the observer can be prevented.
[0034]
[Embodiments of the present invention]
The backlight device in the display device of the present invention is preferably three types of light emitting elements having different emission wavelength peaks, and the colors corresponding to the emission wavelength peaks of each type of light emitting element are preferably three primary colors. Thereby, an image of an arbitrary color can be displayed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a display device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of a main part of the display device according to an embodiment of the present invention. FIG. 4 is a diagram showing a display example by the display device according to the embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Display apparatus 3 Emitting apparatus 4 Combiner 11 Liquid crystal display 12 Backlight apparatus 13 Control apparatus A Observer L1 Image display light beam

Claims (1)

An image display beam emitting device;
In a display device comprising a combiner that changes the optical path to guide the image display light beam to the observer's visual field and transmits the light beam from the observer's front visual field,
The image display beam emitting device is:
A transmissive monochrome simple matrix liquid crystal display whose liquid crystal operation mode is BTN mode;
A backlight device capable of changing the emission wavelength peak of the irradiation light of the liquid crystal display;
A display device comprising means capable of synchronizing the image display timing of the liquid crystal display and the light emission timing due to a desired light emission wavelength peak of the backlight device.

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