(12) United States Patent
`Tokito et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,259,423 B1
`*Jul. 10, 2001
`
`US006259423B1
`
`(54) DISPLAY DEVICE USING ORGANIC
`ELECTROLUMINESCENT ELEMENTS
`
`(75)
`
`Inventors: Shizuo Tokito; Yasunori Taga, both of
`AiChi_ken (JP)
`.
`.
`.
`.
`(73) Assignee: Kabushlkl Kalsha Toyoto Chuo
`Kenkyusho, AiChi_gun (JP)
`
`................... .. 359/630
`5/1990 Banbury etal.
`4,927,234 *
`4/1995 Dodabalapur et al.
`428/690
`5,405,710 *
`
`............ .. 428/690
`5,478,658 * 12/1995 Dodabalapur et al.
`
`5554911
`
`9/1996 Nakayama 6‘ a1~ ~
`.............. 428/690
`1l?(§)1:lizt1(l))aelzt1pi111ret al.
`*
`5,828,181 * 10/1998 Okuda ............................. .. 315/169.3
`*
`’
`’
`6,005,651
`12/1999 Takahara et al.
`.................... 349/137
`FOREIGN PATENT DOCUMENTS
`
`(*) Notice:
`
`This. patent issued on a continued pros-
`ecution application filed under 37 CFR
`1.53(d), and is subject to the twenty year
`patent
`term provisions of 35 U.S.C.
`154(a)(2).
`
`9/1994 (JP) .
`06275381
`8/1996 (JP)
`08213174
`7/1997 (JP)
`9480883
`* cited by examiner
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/134,830
`
`(22)
`
`Filed:
`
`Aug. 17, 1998
`
`(30)
`
`Foreign Application Priority Data
`
`Aug. 26, 1997
`
`(JP) ................................................. .. 9230091
`
`Int. Cl.7 ..................................................... .. G09G 3/22
`(51)
`(52) U.s. Cl.
`.......................... .. 345/76; 313/504, 313/506;
`313/509
`
`(58) Field of Search ................................ .. 345/7, 8, 9, 76;
`359/630; 313/498, 501, 504, 506, 507,
`508, 509
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`.
`9/1985 Vanslyke et al.
`4,539,507
`...................... .. 345/77
`7/1989 Kuwata et al.
`4,847,609 *
`4,876,594 * 10/1989 Schiffman .......................... .. 348/115
`
`Primary Examiner—Richard Hjerpe
`Assistant Examiner—Ronald Laneau
`
`(74) Attorney, Agent, or Firm—Oblon, Spivak, McClelland,
`Maier & Neustadt, P.C.
`
`(57)
`
`ABSTRACT
`
`For use in a display device, a simple-matrix-drive-type
`luminescent panel is formed by stacking a dielectric mirror
`layer, a transparent electrode, a hole transport
`layer, a
`luminous layer, and a metal electrode on a glass substrate,
`wherein the transparent electrode is formed as a plurality of
`stripes equally spaced apart a specified distance from each
`other, and the metal electrode is formed as a plurality of
`stripes equally spaced apart a specified distance from each
`other and arranged at right angles with the transparent
`electrode stripes, and pixels are formed at intersections of
`the metal electrodes and the transparent electrodes and
`wherein in order for the pixels of the panel to emit light to
`display information, the application of a voltage to the pixels
`is controlled by selection of the electrodes according to
`information. This luminescent panel contributes to reduc-
`tions in size and weight of the display device.
`
`25 Claims, 10 Drawing Sheets
`
`
`
`Valeo Exhibit 1006_001
`
`Valeo Exhibit 1006_001
`
`

`
`U.S. Patent
`
`J U ~ . 10,2001
`
`Sheet 1 of 10
`
`US 6,259,423 BI
`
`I METAL ELECTRODE b 2 0
`I LUMINOUS LAYER LI8
`,, 16
`I ELECTRODE
`
`HOLE TRANSPORT
`LAYER
`TRANSPARENT
`
`>I2 DIELECTRIC
`MIRROR
`
`GLASS
`SUBSTRATE
`
`Fig. 1
`
`Fig. 2
`
`Valeo Exhibit 1006_002
`
`

`
`U.S. Patent
`
`Jul. 10,2001
`
`Sheet 2 of 10
`
`EMISSION PATTERN
`
`Fig. 3
`
`Valeo Exhibit 1006_003
`
`

`
`Z
`
`
`
` 111319cI°S'[1
`
`36
`
`
`
`°“"’E"“
`
`
`
`38d
`
`42
`
`44
`
`OSCILLATOR
`
`OSCILLATOR
`
`Fig. 4
`Fig. 4
`
`BOOSTER
`CIRCUIT
`
`40
`
`CLOCK
`GENERATOR
`CIRCUIT
`
`DRIVER
`
`ORGANIC
`
`I00z‘0I‘I111’
`
`EL PANEL 01J09193118
`
`
`
`IEI€ZI7‘6SZ‘9Sn
`
`Valeo Exhibit 1006_004
`
`Valeo Exhibit 1006_004
`
`

`
`U.S. Patent
`
`J U ~ . 10,2001
`
`Sheet 4 of 10
`
`Fig. 5
`
`Fig. 6
`
`Valeo Exhibit 1006_005
`
`

`
`U.S. Patent
`
`J U ~ . 10,2001
`
`Sheet 5 of 10
`
`US 6,259,423 BI
`
`BLUE COLOR EMISSION
`
`Fig. 7a
`
`Fig.
`
`WAVELENGTH
`
`RED COLOR EMISSION
`
`WAVELENGTH
`
`GREEN COLOR EMISSION
`
`MICRO-OPTICAL
`RESONATOR TYPE ELEMENT 1 *
`MICRO-OPTICA
`RESONATOR TYPE ELE
`Fig. 7c
`
`I
`
`ORIGINAL EMlSSlO
`
`WAVELENGTH
`
`Valeo Exhibit 1006_006
`
`

`
`U.S. Patent
`
`J U ~ . 10,2001
`
`Sheet 6 of 10
`
`Valeo Exhibit 1006_007
`
`

`
`U.S. Patent
`
`Jul. 10,2001
`
`Sheet 7 of 10
`
`Fig. 9
`
`Fig. 10
`
`Valeo Exhibit 1006_008
`
`

`
`Fig. 11 PRIOR ART
`
`Valeo Exhibit 1006_009
`
`

`
`U.S. Patent
`
`Jul. 10,2001
`
`Sheet 9 of 10
`
`Valeo Exhibit 1006_010
`
`

`
`U.S. Patent
`
`J U ~ . 10,2001
`
`Sheet 10 of 10
`
`Fig. 13 PRIOR ART
`
`Fig. 14A
`
`WAVELENGTH
`Fig. 148
`
`Valeo Exhibit 1006_011
`
`

`
`US 6,259,423 B1
`
`BACKGROUND OF THE INVENTION
`
`1
`DISPLAY DEVICE USING ORGANIC
`ELECTROLUMINESCENT ELEMENTS
`
`2
`is injected into a liquid crystal panel 162 that includes a
`polarizing plate. The light, modulated by the liquid crystal
`panel 162, passes through an aberration-corrected lens sys-
`tem 164 and a mirror 166, and is projected onto a hologram
`s optical element (a diffraction grating) 168 provided on the
`1. Field of the Invention
`windshield glass. Accordingly, a virtual image of an image
`The Present invention relates to a display device using
`formed in the liquid crystal panel 162 is made to appear in
`organic electroluminescent (EL) elements.
`front of the windshield glass.
`2. Description of the Related Art
`Incidentally, in the display mentioned above, light loses
`Various types of display devices are known, one of which 10 its power greatly when it passes through the liquid crystal
`is a projector type display. This projector type display
`panel. To produce color images, three primaries are gener-
`normally uses a liquid crystal panel. More specifically, a
`ated from white light emitted from a light source, and the
`transmitted light is obtained by controlling each liquid
`rays of three primaries are transmitted through the three
`crystal element of the liquid crystal panel according to video
`liquid crystal panels, respectively. In this case, the utilization
`information and also by controlling the transmitted light by 15 factor of light is 10% or so. Therefore, to produce bright
`using a polarizing plate. Then, by projecting the transmitted
`images, it is required to irradiate the liquid crystal panel with
`light at a high luminance of about 10000 cd/m2. Normally,
`light controlled according to the video information onto a
`screen, a video image is displayed.
`a metal halide lamp or a halogen lamp is used as the light
`Source. A high voltage needs to be used for the light source,
`FIG. 11 shows an example of the conventional full-color
`illustrated, a reflector 104 is 20 and in this case, there is a problem that high heat is generated
`projector type display,
`disposed behind a light source 102, with the result that a
`by the light source. To obtain an adequate transmitted light,
`beam of white light is emitted fornard, ~h~
`it is necessary to irradiate the liquid crystal panel with light
`beam is first reflected by a mirror 106 and is then incident
`with sufficient parallelism. To this end, it is necessary to
`on a dichroic mirror 108, which is arranged tilted 450 from
`provide the light source with a large reflector, which is a
`the optical path, and only yellow light is reflected by the 25 hindrance to the movement toward weight and size reduc-
`mirror 108 in a direction at right angles with the optical path
`tions of the device itself. Another problem is the need to
`before reflection. Therefore, the transmitted light of the
`provide a large cooling fan for the light source.
`mirror 108 is red light. This red light is reflected in a
`With regard to the HUD in automobiles or airplanes, there
`specified direction by a mirror 110. When the yellow light
`are requirements to decrease the size, weight and energy
`reflected by the dichroic mirror 108 is incident on a dichroic 30 consumption. Those problems with the projector type dis-
`mirror 112, green light is separated and reflected in a
`play have been obstacles to the widespread use of HUD.
`right-angle direction, and blue light Passes through the
`In the area of devices for information display, there are
`mirror 112. The blue light reflects through mirrors 114 and
`CRT, the liquid crystal display, the plasma display, the
`116 and goes on to a specified direction. Liquid crystal
`inorganic EL display and so on, H
`~
`~these kinds of
`
`panels 120, 122 and 124, each including a polarizing plate, 35 displays are designed to provide a wide angle of field, and
`are disposed close to the three sides of a dichroic lens 126
`make it possible for the viewers to look at the displayed
`and accept red light, green light and blue light, respectively.
`information from a diagonal direction. On the other hand,
`The liquid crystal panels 120, 122 and 124 cause the red,
`with some displays, it is desired that the angle of field be
`green and blue light, modulated by the control of the liquid
`limited. In the liquid crystal displays, which are not spon-
`crystals, to fall on the dichroic lens 126. The dichroic lens 40 taneous luminescent type displays, the angle of field can be
`126 combines those rays that go into the above-mentioned
`narrowed easily, but there is a problem that it is difficult to
`three sides to form a parallel beam, which is emitted from
`achieve an image display with high luminance, with display
`the one other side. A screen 130 is installed across a lens 128
`on the instrument panel of a car, it is required that an
`in front of the one other side of the dichroic lens 126. The
`information display should be visible to the driver only and
`red, green and blue rays, which have been n~odulated 45 that high luminance should be provided to secure enough
`separately by the liquid crystal panels 120,122 and 124, are
`visibility even when there is direct sunlight coming into the
`combined, and a full-color image is displayed on the screen
`car. Therefore, in view of the above requirements, the liquid
`130.
`crystal display device was not preferable. There are displays
`Among the projector type display devices are audio-visual
`that use LED or a fluorescent indicator tube (a magic eye),
`displays to show a TV screen or the like and head up
`but they are only capable of simple display, and are not
`displays (HUD) used in automobiles or airplanes. In the
`suitable for display with high resolution.
`HUD, light rays that have passed through the liquid crystal
`SUMMARY OF THE INVENTION
`panel are projected by means of a dichroic filter or a
`hologram optical element.
`It is an object of the present invention to provide a display
`FIG. 12 shows an example of the structure of a conven-
`device simple in structure and easy to reduce the size and
`tional dichroic system HUD. In front of a light source 140
`weight.
`formed by a halogen lamp (or a xenon lamp), there is a liquid
`According to the present invention, a display device
`crystal panel 142. A transmitted light of the liquid crystal
`comprises a luminescent panel (organic EL panel) having
`panel 142 passes through a shutter 144, a mirror 146 and a 60 organic electroluminescent elements (organic EL elements)
`collimating lens 148, and is applied to a dichroic filter 150
`arranged in a matrix, and a driver for driving the individual
`attached to the inner surface of the windshield glass. Thus,
`organic EL elements of the luminescent panel on the basis of
`a virtual image of an image modulated by the liquid crystal
`video information.
`panel 142 appears in front of the windshield glass.
`As described above, in the present invention, the lumi-
`FIG. 13 shows an example of the conventional hologram 65 nescent panel is formed by arranging the organic EL ele-
`system HUD. A light from a light source 160 formed by a
`ments in a matrix formation. Therefore, an image can be
`halogen lamp (or a xenon lamp) or a CRT (cathode ray tube)
`displayed according to video information, that is, by causing
`
`~
`
`~
`
`~
`
`55
`
`Valeo Exhibit 1006_012
`
`

`
`US 6,259,423 B1
`
`3
`4
`up displays. With the head up displays, particularly those
`desired organic EL elements to emit light. Being spontane-
`ous luminescence elements, the organic EL elements do not
`attached to the windshield glass of vehicles, a sufficient
`require a light source. The organic EL panel, which gener-
`visibility of information displayed must be secured without
`ates light according to video information, does not require a
`sacrificing the visibility of the view in front of the car, and
`transmission type liquid crystal panel or the like, and there- 5 a light source for very high luminance of the screen is
`fore the generated light can be utilized one hundred percent.
`present, the luminance of the xenon lamp is
`required,
`As a result, the organic EL panel can make a high-luminance
`3000 cd/m2 and its service life is about 100 hours,
`an
`with ease. Furthermore, being
`image
`of
`ideal light source, a light source should desirably have a life
`outputting images only with the organic EL panel, the
`of lo000 hours when used at a luminance of 10000-15000
`display device according to the present invention can be
`10 cd/m2, but such a light source has yet to be developed. When
`formed in a simple structure, and can be produced in a
`a Fresnel lens or the like is used, because of its low light
`smaller size and with a lighter weight easily, If a liquid
`transmittance and the no directivity of the emitted light,
`crystal panel is used, a light source needs to be added, and
`there is a great loss of light.
`because of this, a problem of heat generation arises.
`With the organic E L ~ a n e l , since the panel generates light
`However, heat generation is less of a problem with the
`by itself, the produced light can be utilized one hundred
`organic ELpanel. On the contrary, there is a merit that its flat
`percent. Therefore, the organic EL panel can perform dis-
`panel is superior in heat dissipation.
`Suitable for this organic EL panel is a m ~ c r o - o p t ~ c a ~ play with high luminance while keeping light loss a mini-
`EL panel is used, the
`mum level. When the
`resonance type organic EL element disclosed in Japanese
`Can be structured in a
`form, thus offering chances of
`Patent Laid-Open Publication No, Hei-9-180883, By the use
`of an organic EL element such as this, it is possible to obtain 20 reductions in size and weight. When a display is mounted on
`light with high luminance, high directivity and better mono-
`a vehicle, the essential requirement of the display is a
`chromaticity, It also becomes possible to easily display an
`compact size, and to this end, it is most desirable to use the
`image with a high luminance of 10000 cd/m2.
`organic EL panel. Be it a dichroic system or a hologram
`system, an organic EL panel can preferably be used.
`An organic EL element such as this is formed by stacking 25
`In addition, the organic EL pane'
`preferably be
`a dielectric mirror, a transparent electrode, a hole transport
`used as is to achieve a high-directivity display. As described
`layer, a luminous layer, and a metal electrode on a glass
`EL
`the micrO-O~tical
`substrate. By placing the transparent electrodes and the
`type
`has high directivity. Therefore, an organic EL panel using
`metal electrodes so that their stripes perpendicularly inter-
`those organic EL elements provides better visibility to the
`sect each other, the pixels can be arranged at the intersec-
`faces the panel, but the
`tions of those electrodes in a matrix formation. Accordingly, 30 viewer
`decreases sharply when the viewer shifts to either side. With
`a display device with a simple matrix type drive can be
`a display on the instrument panel of a vehicle, the visibility
`realized by controlling the application of a voltage between
`should be secured only for the driver, so that this type of
`the transparent electrodes and the metal electrodes.
`preferably be used.
`arranging to provide
`The light from the organic EL panel is preferably pro-
`jetted through a projection lens to a screen, Being free from 35 a high visibility when the driver sits up straight, the driver
`EL panel,
`straighten up. With the
`Can be made
`power attenuation during transmission through the liquid
`with a high luminance
`images can be
`10000
`crystal or the polarizing plate, the present invention can
`cd/m2 or higher, as the result, the driver can easily view the
`realize a high-luminance projector type display.
`displayed information when the sun is shining in through the
`Preferably, three matrix type organic EL panels for dif-
`40 window or the driver is an elderly person.
`ferent luminescent colors are provided, the light emission of
`those panels is controlled according to information, and the
`rays of different colors are combined and projected onto a
`screen. By allotting the three organic EL panels to the three
`primary colors (R, G and B), a full color image can be 45 EL pane';
`FIG. 2 is a perspective view showing the structure of the
`displayed on the screen. In the case of a conventional
`organic EL panel;
`full-color projector type display, the light from the light
`FIG. 3 is a diagram showing a luminescence pattern;
`source must be separated by dichroic mirrors, for example,
`into primaries R, G and B, so that the device necessarily
`FIG. 4 is a block diagram showing the general composi-
`becomes large in size. Another problem is that because the 50 tion of the display, including driver circuits;
`light must be sufficiently parallel, the production of the
`FIG. 5 is a diagram showing the structure of a mono-color
`optical system is troublesome, and its weight becomes
`display;
`heavy. Moreover, the dichroic mirrors are very expensive. In
`FIG,
`is a diagram showing the composition of a full-
`order to produce a distinct image, the liquid crystal is
`color display;
`required to have a large contrast ratio (100:l to 1000:l). In 55
`FIGS. 7a, 7b and 7c are diagrams showing wavelengths of
`addition, the luminance of the light source is required to be
`luminescence;
`10000 cd/m2 or higher.
`is a diagram showing the structure of a
`In the above-mentioned structure according to the present
`'yStem HUD;
`invention, the organic EL panels generate primaries R, G
`is a diagram
`and B with high directivity, respectively, so that the structure 60
`HUD;
`of the device is simple and the optical system can be
`FIG. 10 is a diagram showing the arrangement of a direct
`obviated. Furthermore, the organic EL panel can produce a
`viewing type display;
`high luminance, for which reason a distinct image can be
`FIG. 11 is a diagram showing the structure of a conven-
`obtained easily, and not many problems, such as heat
`generation, will be encountered.
`65 tional full-color display;
`FIG. 12 is a diagram showing the structure of a conven-
`Preferably, the light, including video information, which
`is generated by the organic EL panel is utilized in the head
`tional dichroic system HUD; and
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`is a diagram showing the structure of the organic
`
`the structure
`
`a
`
`Valeo Exhibit 1006_013
`
`

`
`US 6,259,423 B1
`
`5
`FIG. 13 is a diagram showing the structure of a conven-
`tional hologram system HUD;
`
`FIGS. 14A and 14B are diagrams showing a structure that
`enables a full-color display by a single luminescent panel.
`
`DESCRIPTION OF PREFERRED EMBODIMENT
`
`An embodiment of the present invention will be described 10
`with reference to the accompanying drawings.
`
`6
`-continued
`
`!<,(')$,
`ON-----?
`0 "0
`
`ALUMIQUINOLINOL COMPLEX
`
`o
`H
`QUINACRIDONE
`
`[Structure of the Organic EL Panel]
`FIG. 1 is a diagram showing the structure of an example
`of an organic ELpanel according to a preferred embodiment
`of the present invention. The basic structure of a piece of
`electroluminescent element is the same as in Japanese Patent
`Laid-Open Publication No. Hei-9-180883. This element is
`organized by forming a dielectric mirror 12, a transparent 20
`electrode 14, a hole transport layer 16, a luminous layer 18,
`The organic EL panel according to the present embodi-
`and a metal electrode 20 in this order on a glass substrate.
`ment includes the transparent electrodes 14 and the metal
`The glass substrate lo is in a
`form with
`electrodes arranged so as to intersect each other as shown in
`2.5-inch diagonal lines. The dielectric mirror 12 is obtained 25 FIG. 2, and the organic EL elements are located at the
`by alternately forming a SiO, layer and a TiO, layer. Each
`intersections of the two kinds of electrodes. More
`layer of SiO, and TiO, of the dielectric layer 12 is deter-
`
`s~ecificall~, the organic EL panel is a simple matrix type
`Of a 580-nm wavelength of the center
`panel, which includes 20 horizontal lines of the 2-mm-wide
`mined so as to be
`transparent electrodes 14 and 30 vertical lines of the 2-mm-
`frequency of the stop band. The transparent electrode 14 is
`wide metal electrodes 20.
`formed of IT0 (indium tin oxide), and the space between the 30
` hi^ organic EL panel is formed as follows, ~h~ dielectric
`metal mirror and the dielectric mirror is set at about % of or
`,irrOr 12 and the transparent electrode 14 are deposited by
`about the same as the wavelength of light that is made to
`the RF magnetron sputtering process. The transparent elec-
`trode 14 is etched so as t~ be in stripes by wet etching. Then,
`resonate. In this example, the thickness of the transparent
`the hole transport layer 16 and the luminous layer 18 and the
`electrode 14 is 40 nm.
`35 metal electrode 20 are deposited in this order by the vacuum
`For the hole transport layer 16, a triphenyldiamine deriva-
`evaporation process. The metal electrode 20 is formed in
`stripes by using a mechanical mask. Subsequently, the
`tive is used, and its thickness is set at 55 nm. For the
`organic EL panel is encapsulated by a glass plate and a
`luminous layer 18, an alumiquinolinol complex is used, and
`ultraviolet cured resin. If necessary, the panel may be fitted
`its thickness is set at 40 nm, hi^ luminous layer 18 is doped
`quinacridone in order to improve luminous 40 on its rear side with a radiator plate or a cooling fan to
`with about
`restrain the temperature rise of the panel.
`efficiency. The thickness of an organic layer consisting of the
`In the organic EL panel according to the present
`transport layer l6 and the luminous layer l8 is set such
`embodiment, the dielectric mirror 12 and the metal electrode
`that the
`a
`20
`535
`a micro-optical resonator, This micro-optical
`which is close to a peak on the short wavelength side of 45 resonator causes resonance of a ray of a specific wavelength
`the emission spectrum of quinacridone to prevent other
`among the rays output from the organic layer made of the
`resonance wavelengths from occurring in the spectrum of
`hole transport layer 16 and the luminous layer 18, and this
`quinacridone. For the metal electrode 20, MgAg is used.
`ray is radiated with high directivity in the direction of the
`front face of the panel. FIG. 3 is a schematic diagram of the
`The structures of the triphenyldiamine derivative, the
`SO emission pattern. As depicted, a ray with high directivity is
`alumiquinolinol complex, and quinacridone are shown
`emitted in the direction of the front face.
`below.
`Therefore, by increasing the luminance in the direction of
`the front face, a high-luminance panel can be realized. The
`above-mentioned structure is an example, and thus for the
`55 materials of the layers of the organic ELpanel, various kinds
`of materials described in Japanese Patent Laid-Open Publi-
`cation No. Hei-9-180883 may be adopted. The material and
`the thickness are varied with different kinds of luminescent
`color.
`60 [Structure of the Driver Circuit]
`FIG. 4 shows an example of the structure of the organic
`luminescent panel, which also shows driver circuits. Two
`booster circuits 32, 34 are connected to a 4.5V DC power
`source 30. The booster circuit 32 can output voltages in the
`65 range of 5V to 12V. The output voltage of this booster circuit
`32 is supplied to a driver 36. The booster circuit 34 outputs
`a constant voltage of 5V. The output voltage of the booster
`
`[Chemical Formula 11
`
`CH3
`CH3
`TRIPHENYLDIAMINE DERIVATIVE
`
`Valeo Exhibit 1006_014
`
`

`
`US 6,259,423 B1
`
`2s
`
`
`
`8
`7
`circuit 34 is supplied as a source voltage to a microcomputer
`better monochromaticity, the luminance on the organic EL
`38. The microcomputer 38 comprises an 110 interface 38a
`panel 48 was 10000 cd/m2, the luminance on the screen 52
`for exchange of signals with outside devices, a ROM 38b for
`was 200 cd/m2, and a distinct image was projected on the
`storing programs, a RAM 38c for storing various items of
`screen 52,
`data, and a CPU 38d for performing various operations. A s
`the organic EL
`According to the present
`clock generator circuit 40, connected to the microcomputer
`panel emits light by itself, and also serves as information
`38, supplies clock signals to set timing of actions at a
`conversion means for converting video information into
`frequency of 8 M H ~ , T~~ oscillators 42, 44 are connected
`light. Therefore, the organic EL panel 48 performs two
`to the microcomputer 38. The oscillator 42 supplies signals
`of 5 MHz to 50 MHz to control displaying speed, and the 10 functions as a light source in a projector type display that
`oscillator 44 supplies signals of 0.2 kHz to 2 kHz to control
`uses a liquid crystal panel, and also as a liquid crystal panel.
`scanning frequency.
`Accordingly, the organic EL panel 48 is very simple in
`An organic EL panel 48 is connected through two drivers
`,tructure, since the organic EL panel 48
`light
`to the microcomputer 38. The driver 36 is a circuit to control
`spontaneous~y, there is no light loss that would occur when
`whether or not to apply a voltage, supplied from the booster 1s light is passed through a liquid crystal panel or a polarizing
`circuit 32 as described above, to the organic EL panel, and
`plate, for which reason the light utilization factor is high,
`is formed of transistors respectively connected to the vertical
`Thus, it is easy to produce bright images, and heat genera-
`electrodes in the organic EL panel 48. When a transistor in
`tion is relatively low, On the flat organic EL panel 48, a
`the driver 36 is turned on, a voltage from the booster circuit
`radiator plate or the like can be installed easily and will
`32 is applied to a vertical electrode connected to this 20
`eficienc~. Therefore, the
`exhibit great
`transistor, On the other hand, the driver 46 is formed of
`device can be reduced in size and weight
`the
`transistors respectively connected to the horizontal elec-
`general configuration of the device, and therefore clear
`trodes in the organic EL panel 48, When a transistor in the
`images can be produced.
`driver 46 is turned on, a horizontal electrode connected to
`For the screen 52, a reflection type screen or a transmis-
`this transistor is connected to earth.
`In the display device structured as described, when the
`sion type screen can be applied. The screen can be used also
`microcomputer 38 controls the drivers 36 and 46 to turn on
`for a display device on a vehicle with a limited display area.
`[structure
`one transistor each, voltage is applied across one vertical
`of the ~ ~ l
`
`
`l~
`- ~ ~ l ~ ~ i ~ ~ l ~
`
`
`
`
`~
`l
`electrode and one horizontal electrode, with the result that an
`organic EL element at the intersection of the two electrodes 30 . FIG. 6 shows a full-color projection type display. As
`three organic EL panels 48R,
`lllustrated, this
`light, Therefore, when one horizontal line is selected
`48G and 48B for red, green and
`rays. Those three
`by a transistor of the driver 46 and under this condition the
`48G and 48B are arranged
`EL panels 48R3
`driver 36 turns on the transistors specified by data for that
`the three sides of a dichroic prism 56. Aprojection lens 50
`line, the display of data is effected at the pixels of one
`horizontal line, B~ repeating this scanning action in the 35 is arranged in front of the one other side of the dichroic
`prism 56. A screen 52 is disposed further ahead of the
`vertical direction, the display of one picture can be achieved.
`Preferably, the horizontal driver 36 is provided with a data
`projection lens 50.
`register for one line to thereby drive the transistors accord-
`The dichroic prism 56 combines the rays coming in from
`ing to stored data.
`the three sides, and emits the rays toward the projection lens
`Video data for display may be supplied externally in step 40 50. Therefore, the rays generated in the three organic EL
`with the internal display cycle. Prearranged Patterns of
`panels 48R, 48G and 48B are combined to form a full-color
`in ROM 38B and
`characters Or the like may be
`picture on the screen 52. The three organic EL panels 48R,
`displayed. In ordinary NTSC-system television broadcast, a
`48G and 48B may be driven according to display data of R,
`video signal is sent at horizontal and vertical scanning
`and
`colors,
`frequencies specified by a standard. The horizontal and 45
`The organic EL pane' 48G for green light may be strut-
`vertical synchronizing signals are separated from the video
`tured as described above. The organic EL panel 48B for blue
`signal, and the video component is converted into digital
`light may be formed by making the luminous layer of a
`signals corresponding to the number of pixels of the organic
`benzoxazole zinc complex and setting the resonance wave-
`EL panel, As those signals are supplied to the microcom-
`puter 38, the video signal is displayed on the organic EL so length at 450 nm. The organic EL panel 48R for red light
`panel 48 in step with the horizontal and vertical synchro-
`may be realized by forming the luminous layer of DCM and
`nizing signals.
`setting the resonance wavelength at 610 nm. The structures
`[Structure of the Mono-color Display]
`of a benzoxazole zinc complex and DCM are shown below.
`FIG. 5 shows an example of a projector type display
`utilizing the above-mentioned organic EL panel 48. In this ss
`example, a mono-color display is performed. A projection
`lens 50 is placed in front of the organic ELpanel48. Further
`ahead of the panel 48, a screen 52 is set. Thus, a displayed
`image on the organic EL panel 48 is magnified by the
`projection lens 50, and brought to a focus on the screen 52. 60
`In other words, the image on the organic EL panel 48 is
`projected onto the screen 52. The radiator plate 54 is used to
`dissipate the heat of the organic EL panel 48.
`In the display structured as described, characters were
`displayed by driving the organic EL panel 48 with a matrix 65
`of 30 horizontal lines x20 vertical lines, a duty ratio of l432,
`and a voltage of 15V. The luminescent color was green with
`
`BENZOXAZOLE ZINC COMPLEX
`
`[Chemical Formula Z]
`
`Valeo Exhibit 1006_015
`
`

`
`/CH3
`
`N I
`
`CH3
`
`DCM
`
`10
`
`30
`
`US 6,259,423 B1
`
`9
`-continued
`
`H3C
`
`J?&
`
`10
`With this kind of display device, rays of light for projec-
`tion were conventionally obtained by passing light from a
`light source through a liquid crystal panel. In this conven-
`tional device structure, the light attenuation by the liquid
`5 crystal panel is great, so that it is necessary to provide a light
`source of large light quantity to obtain a high luminance.
`Therefore, the heat generated by the light source is large and
`heat dissipation has been a troublesome problem.
`In the present embodiment, not much heat is generated
`because the organic EL panel 48 emits light by itself, and
`heat can be dissipated relatively easily because the organic
`EL panel 48 is flat in shape. Its structure is simpler than in
`a type of device that has a light source and a liquid crystal
`panel provided separately. Therefore, the general device
`structure can be made in a compact form. In an application
`The number of layers and the reflectance of the dielectric 1s as a full-color display, because of its very simple structure,
`mirror 12 can be varied, with the result that the spectral
`it can be preferably mounted on a vehicle.
`half-width of an emission wavelength (corresponding to
`[Dichroic System HUD]
`color purity) and the degree of light amplification can be
`FIG. 9 shows a structural example of a dichroic system
`controlled. Furthermore, fine adjustment of an emission
`head up display (HUD) mounted on a vehicle. A mirror 70
`wavelength is possible by varying a resonance wavelength. 20 is arranged in front of an organic ELdisplay 48, and the light
`In other words, by providing a resonator, each luminescent
`reflected from the mirror 70 passes through a collimating
`lens 72, and is applied to a dichroic filter 74 attached to the
`color can be made to have better monochromaticity than the
`luminescent color from the organic layer as shown in FIGS,
`inner su