EP1510995A2 - Display apparatus - Google Patents

Abstract

The device (1) has a display (4) switchable at least temporarily into a transparent state, at least over part of its area, to enable the observer (3) to observe the background (31) behind the display. The display has a first switchable filter at least over part of its area that can be switched between an essentially diffuse, at least partial transmission state and an essentially transparent, at least partial transmission state. An independent claim is also included for the following: (a) a method of operating an inventive device.

Description

The invention relates to a display device with a display, which display at least temporarily at least partially is transparent switchable and in this way on the from a viewer behind the display device located Background in the transparent area the display shows.

Display devices of the aforementioned type sometimes find Application for articles of the consumer goods industry, eg. B. at electronic grandfather clocks, which by means of this arrangement have a special design. Despite the strong desire in the field of equipment of motor vehicles, find such transparent displays so far no application, because the usually changing lighting conditions during operation a motor vehicle, a poor readability of such Ads result. For example, is the ad on the transparent display for a good readability designed in strong ambient light by, for example black numbers on the otherwise transparent display field can be generated, the motor vehicle driver in a Driving in an environment of weak extraneous light, for example when driving through a tunnel, the ad is not read more. The lack of readability of conventional transparent display fields is already fluctuating Light conditions recorded, for example, at a ordinary cornering in a backlit situation or off a backlight situation out. Already here it is possible human eye the information presented due to the strongly fluctuating contrast and the considerable brightness difference no longer satisfying to capture.

Based on the problems and disadvantages of the state of Technique is the invention of the object, a display device with one at least partially and at times to create transparent display, which is also changing Light is easy to read.

According to the invention the object is achieved in that the display at least partially a switchable first filter which is between a substantially diffuse, at least partial transmission and one essentially transparent at least partial transmission back and forth is switchable. The possibility of diffuse transmission eliminated the disturbing influence of changing ambient light conditions on the readability of the display as needed. Thus, for example, in daylight by means of circuit of the first filter in the diffusely scattering mode homogeneous luminous background are generated on which the information to be conveyed is displayed. Increases the Brightness of the ambient light will be equally beneficial also the homogeneous glowing background brighter. The Contrast ratios remain due to the diffuse scattering the backlight remains highly consistent despite changing light conditions. For an operation in the dark or at night, when brightness variations of the background less strong, it is appropriate to the first To operate filters substantially transparent and optionally in addition to illuminate.

An advantageous development of the invention provides that the first filter is a polymer-dispersed liquid crystal cell or a polymer dispersed liquid crystal display (PDLCD). A PDLCD is extremely easy to read because it does not require a polarizing filter and therefore especially bright. In addition, PDLCD's are because of it's one high accuracy in the thickness of the liquid crystal dispersion layer not needed, compared to other known Display devices are relatively inexpensive produced.

Advantageously, the PDLCD in the display device according to the invention designed to be controlled matrix, so that the information to be displayed directly on this can. In addition or instead, the PDLCD can also be controlled Have segments, by means of which symbols can be displayed are, for example, in the style of a 7-segment display.

When using the display device according to the invention in one Motor vehicle as an information system it makes sense when the display device is arranged so that from the outside incoming ambient light pass through and from the viewer can be perceived and the viewer of the him from behind the display device located landscape image on request in the transparent areas recognize the ad. Should just the landscape be perceived as disturbing, the readability means switching to the diffusely scattering mode of the first Filters are improved.

A particularly expedient development of the invention sees before that in series with the first filter, a second filter is arranged, which at least partially between a first state in which he is essentially transmissive is and a second state in which he is essentially is not transmissive, is switchable back and forth. As well as in the switchability of the first filter is also in the Switchability of the second filter not only the purely binary Setting two different states makes sense but also prefers a gradual adjustment of transparency or the scattering effect in the first filter and the transmission at the second filter. In this way can always be optimal Adaptation to the environmental situation and the user can depending on his preference, for example by means of a controller, desired brightness and scattering effects each one more or less sharp Provide contrast. Preferably, instead or additionally to the adjustment for the user an automatic Adjustment of the scattering effect and the brightness the ambient light is preferred.

Suitably, the second filter is a liquid crystal cell (LCD), in particular as a positive LCD. Come here in particular all types of transparent and graphic-enabled Liquid crystal displays in question, preferably also displays with the ability to color representation. Here is It makes sense if the second filter is in the first state not just transmissive but essentially is transparent. If necessary, this can be the background through the display.

For excellent readability in all ambient light conditions, especially in the dark, it makes sense if from the viewer behind the display a Backlight is arranged. Taking advantage of the special properties of the first filter is beneficial the arrangement of at least one illumination possible, which in Essentially perpendicular to the viewing direction laterally in irradiates the first filter. Is the beam path this Light source substantially parallel to the display plane, finds a decoupling in the direction of the viewer only in the areas where the first filter diffused is switched to scattering. In other areas, the viewer takes no lighting true. Let that way makes sense the information to be presented in the form of Show symbols and similar designs. In an arrangement a lighting behind the display, this is appropriate transparent, for example, as a flat organic light emitting diode (OLED).

So that it is not a permanent one for a good readability manual correction is required by the viewer, it is expedient if the display device at least one sensor and a controller, the sensor is the ambient brightness measures and the result of the measurement to the controller the display device is transmitted. The control of Indicator accordingly fits the scattering effect of first filter and the transmission of the second filter in areas on the ambient light conditions and the displayed Information.

In addition to the display device and its advantageous developments proposes the invention to solve the problem Method for operating such a display device, in which the ambient brightness is measured and at Exceeding a certain brightness of the first filter is essentially switched to diffuse and on a display the display device to be displayed by means of information a viewing direction in series with the first filter arranged second filter, which at least partially between a substantially transmissive and a substantially Non-transmissive state switchable back and forth is and by means of switching these areas to be displayed Information is displayed to be displayed. This kind of Control helps the display device according to the invention Tasks in changing light conditions to a excellent readability. In development of the invention Method, the readability is improved in the dark, when falling below the measured ambient brightness under a certain brightness the second filter essentially transmissive or transparent is switched and on the display information to be displayed by means of the first filter, which partially to display the displayed Information is displayed. Here, the lighting, as previously described, means a transparent backlighting of the display or a laterally incident in the first filter light source appropriate.

Figur 1:

eine schematische Darstellung einer Einbausituation einer erfindungsgemäßen Anzeigevorrichtung in einem Kraftfahrzeug und die Wirkungsweise,

Figur 2:

eine schematische Darstellung des Aufbaus einer erfindungsgemäßen Anzeigevorrichtung im vom Umgebungslicht gespeisten Durchlichtbetrieb,

Figur 3:

eine schematische Darstellung einer erfindungsgemäßen Anzeigevorrichtung mit einer transparenten Hintergrundbeleuchtung,

Figur 4:

eine schematische Darstellung einer erfindungsgemäßen Anzeigevorrichtung mit einer seitlich in den ersten Filter einstrahlenden Lichtquelle,

Figur 5:

eine schematische Darstellung des erfindungsgemäßen Verfahrens zum Betrieb einer erfindungsgemäßen Anzeigevorrichtung.

In the following, the invention with reference to embodiments with reference to drawings for the sake of clarity only without limitation to the described examples is explained in more detail. Show it:

FIG. 1:

a schematic representation of a mounting situation of a display device according to the invention in a motor vehicle and the mode of action,

FIG. 2:

a schematic representation of the structure of a display device according to the invention in the transmitted by ambient light transmitted light mode,

FIG. 3:

a schematic representation of a display device according to the invention with a transparent backlight,

FIG. 4:

a schematic representation of a display device according to the invention with a laterally irradiating in the first filter light source,

FIG. 5:

a schematic representation of the inventive method for operating a display device according to the invention.

In the illustration of Figure 1 is a display device according to the invention 1 provided with the reference numeral 1 and in a motor vehicle 2 installed. A motor vehicle 2 leading Viewer 3 of the display device 1 takes on the Display 4 the information shown in detail extracts 5 true. The information 5 is the display the current driving speed of the motor vehicle 2, the display 4 due to its transparency in the background recognize the display 4 located landscape image 6 leaves.

Figure 2 shows a simple design of an inventive Display device 1 schematically. The display 4 of the display device 1 consists essentially of a first Filter 10 and a second filter 12, wherein the first filter 10 as a polymer disperse display (PDLCD) and the second filter 12 is formed as a liquid crystal display 13. The polymer-dispersed liquid crystal display 11 can be considered change the transparency or the scattering effect in such a way that, for example, a complete transparency adjustable is, in which the landscape image 6 by means of Ambient light 7 can be clearly seen by the display 4 or that, for example, with completely diffuse scattering the display 54, except for any information presented as homogeneously illuminated by the ambient light 7 display area appears.

The illustrated in Figure 3 training an inventive Display device 1 has in addition to the first filter 10 and the viewing direction following second filter 12 a transparent, areal backlight 14 on, by means of which in the dark by means of the polymer-dispersed liquid crystal display 11 trained first Filter or designed as a liquid crystal display 13 second filter 12 information shown to the viewer 5 3 can be displayed.

The illustrated in Figure 4 embodiment of an inventive Display device 1 provides that by means of a side arranged illumination 15 due to the matrix Control of the first filter 10 or the second filter 12, which is used as polymer dispersed liquid crystal display 11, or are formed as a liquid crystal display 13, shown Information 5 the viewer 3 brought to the display become. The essentially parallel beam path of the illumination 15 is driven in to display the information 5 Scattered areas and in this way in the eye the viewer 3 steered. Unscattered light of the lighting 15 does not reach the eye of the observer 3.

Figure 5 shows an operation of the display device according to the invention 1 according to the inventive method for Control of the display device 1 both in day mode 21st as synonymous in the night mode 22 synoptic. The illustrated display device 1 essentially comprises in an order from the viewer 3 of a positive liquid crystal display 23, a polymer dispersed liquid crystal display 24 and a transparently formed backlight 25. In addition the display device 1 comprises a controller 26, which in cooperation with a sensor 27 for measuring the Ambient brightness of the control of the display 4 is used.

In the case of the daytime operation 21, the controller 26 shuts off the measured brightness of the ambient light 7 the Backlight 25 off. For the most part unattenuated The incident ambient light 7 penetrates the backlight 25 and hits the first filter 10 or the Polymer Dispersive Liquid Crystal Display 11, available from the Control 26 is switched to the diffuse-scattering mode. Of the first filter 10 diffused scattered meets the transmitted Light on the positive liquid crystal display 23, the from the controller 26, the matrix control commands to graphic representation of a symbol 30 has received. The Symbol 30 shows the viewer 3 on the display 4 of Display device 1 according to the invention as a dark representation against a light background 31.

During nighttime operation 22, controller 26 shuts off the measured by the sensor 27 darkness the transparently formed backlight 25. The light emitted from the backlight 25 passes the first filter 10, which of the controller 26 matrix segmented graphic commands for representing a symbol 30 receives. The area of representation of the symbol 30 of the Polymer Dispersive Liquid Crystal Displays 24 is due to the Control commands transmissive switched transparent and the area of the background 31 transmissive diffusely scattering. The from the polymer dispersed liquid crystal display 24 Light hits the positive liquid crystal display 23, which is transmissively transparent by the controller 26 is, so that the viewer 3 in the display 4 a Appears representation, which has a bright icon 30 and one darker due to diffuse scattering Background 31. Will, instead of a background irradiation a lighting 14, 25 from a lateral coupling a lateral illumination 15 in the first filter 10 or the polymer-dispersed liquid crystal display 11, 24 is selected, the result is a substantially dark background 31 and a bright symbol 30 with good contrast for the viewer 3.

Claims (16)

Display device (1) with a display (4), which display (4) at least temporarily, at least partially transparent switchable and in this way from a viewer (3) from behind the display device (1) located background (31) in the transparently connected Detect areas of the display (4)
characterized in that the display (4) at least partially a switchable first filter (10) which is switchable between a substantially diffuse at least partial transmission and a substantially transparent at least partial transmission back and forth. A display device according to claim 1, characterized in that the first filter (10) is a polymer dispersed liquid crystal display (11). Display device according to claim 2, characterized in that the polymer-dispersed liquid-crystal display (11) can be driven in matrix form. Display device according to claim 2, characterized in that the polymer-dispersed liquid-crystal display (11) has controllable segments, in particular for the display of symbols. Motor vehicle information system with a display device (1) according to at least one of the preceding claims, characterized in that the display device (1) is arranged so that outside incoming ambient light (7) can pass through and be perceived by the viewer (3) and the viewer (3) which can detect the landscape image (6) located behind it from the display device (1) in the transparently switched areas of the display (4). Display device (1) according to at least one of the preceding claims, characterized in that in series with the first filter (10), a second filter (12) is arranged, which at least partially between a first state in which it is substantially transmissive and a second state in which it is substantially non-transmissive, switchable back and forth. Display device according to claim 6, characterized in that the second filter (12) is a liquid crystal display. Display device according to at least one of the preceding claims 6, 7, characterized in that the second filter (12) is a positive liquid crystal display LCD (23). Display device according to at least one of the preceding claims 6, 7, 8, characterized in that the second filter (12) is controllable in terms of matrix. Display device according to at least one of the preceding claims 6, 7, 8, 9, characterized in that the second filter (12) in the first state is substantially transparent. Display device according to at least one of the preceding claims, characterized in that from the observer (3) from behind the display (4), a backlight (14) is arranged. Display device according to at least one of the preceding claims, characterized in that at least one illumination (15) radiates laterally into the first filter (10) substantially perpendicular to the viewing direction. Display device according to claim 10, characterized in that the illumination (15) generates a substantially parallel beam path to the display plane. Display device according to at least one of the preceding claims, characterized in that the display device (1) at least one sensor (27) and a controller (26), the sensor (27) measures the ambient brightness and the result of the measurement to the controller (26) the display device (1) is transmitted. Method for operating a display device (1) according to at least one of the preceding claims, characterized in that the ambient brightness is measured, when a certain brightness is exceeded, the first filter (10) is switched substantially diffusely and information (5) to be displayed on the display (4) is arranged by means of a second filter (12) arranged in the viewing direction in series with the first filter (10) is selectively switched back and forth between a substantially transmissive and a substantially non-transmissive state and by means of switching these areas, the information (5) to be displayed can be displayed. A method according to claim 14, characterized in that the ambient brightness is measured, when a certain brightness is not reached, the second filter is switched essentially transmissively or transparently, and information (5) to be displayed on the display (4) is displayed by means of the first filter, which is locally activated to display (4) the information to be displayed.

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