JP2005340823A - Luminous electronic element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminous electronic element in which light emitted by the element shows an optical spectral distribution and the color of the emitted light can be adjusted easily during the operation of the luminous electronic element. <P>SOLUTION: The luminous electronic element includes at least one light-emitting element which emits light having a given spectral distribution, and at least one filter element which is arranged in a path of a beam of the light having the given spectral distribution. In this luminous electronic element, the transmittance characteristic of the filter element regarding the light having the given spectral distribution determines the spectral distribution of the light emitted by the light-emitting element, and can be adjusted during the operation of the luminous electronic element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting electronic device, at least one light emitting element for emitting light having a predetermined spectral distribution, and at least one filter element arranged in a beam path of light having a predetermined spectral distribution. The transmission characteristic of the filter element relating to light having a predetermined spectral distribution relates to a light emitting electronic device of a type that defines a spectral distribution of light emitted by the light emitting device.

  Today, light-emitting electronic elements (especially photoelectric elements) are often manufactured to emit colored light according to unique customer requirements (color on demand).

  For this purpose, light-emitting electronic devices having a relatively broad spectral distribution (eg a suitable white source) are often used. With the color filter, the color of the light emitted by the element is produced according to customer requirements. The “customized” color of a light emitting electronic device is completely determined by the spectral distribution of the light emitted by the device, combined with the absorption characteristics of the color filter. The absorption characteristics of such filters are usually fixed, for example by the dyes used, so it is difficult for the customer to change the color of the light emitted by the electronic element.

  The object of the present invention is therefore to provide a light emitting electronic device with a spectral distribution of the light emitted by the device, in particular the color of the emitted light can be easily adjusted during operation of the device.

  The above problem is solved by a light emitting electronic device characterized in that the transmission characteristics of the filter element can be adjusted during operation of the light emitting electronic device. Advantageous improvements of the invention are described in the dependent claims.

  A light emitting electronic device according to the invention comprises at least one light emitting element for emitting light having a predetermined spectral distribution and at least one filter element arranged in a beam path of light having a predetermined spectral distribution. The transmission characteristics of the filter element with respect to light having a predetermined spectral distribution are of a type that determines the spectral distribution of the light emitted by the light emitting element, the transmission characteristics of the filter element being adjustable during operation of the light emitting electronic element It is.

  Adjusting or changing the transmission characteristics of the filter element advantageously results in a change in the spectral distribution of the light emitted by the light emitting element during operation of the element. The adjustment of the transmission characteristics of the filter element is advantageously reversible.

  In this way, the color of the light emitted by the electronic element can advantageously be adjusted or changed continuously by means of changing the transmission characteristics of the filter element. In this way, different colors or nuances of colors are realized by a single light emitting electronic device.

  In the context of the present invention, the term “color” refers to a pure color or a mixed color, in particular white. Purely colored light has color coordinates x and y in the CIE chromaticity diagram, which refers to a point on the diagram boundary. Mixed and colored light has color coordinates inside the area limited by this boundary.

  The predetermined spectral distribution preferably has a wide bandwidth or a wide spectral distribution, particularly preferably in the visible spectral region. This results in the opportunity to realize different colors of light emitted by the device. This is achieved by using a single light with a predetermined spectral distribution in combination with filter elements having different transmission and / or tuning characteristics.

  More preferably, the predetermined spectral distribution has an essentially continuous shape.

  It is particularly advantageous to have bands in the red, green and / or blue spectral region for a given spectral distribution. By superimposing such bands, a predetermined spectral distribution with a continuous and / or appropriate level of breadth is advantageously obtained. For example, a given spectral distribution produces white or white with a slight tint.

  In a first advantageous embodiment of the invention, the light emitting element comprises at least one photoelectric element. This emits light by electroluminescence in at least one functional material or functional layer. The photoelectric element may be formed corresponding to, for example, an LED structure (light emitting diode) or an OLED structure (in particular an organic light emitting device which is an organic light emitting diode). The OLED structure advantageously comprises at least one organic light emitting material.

  Filter elements corresponding to the present invention may be used to adjust or change the peak wavelength and / or dominant wavelength of the light emitting element. In particular, the light-emitting elements have a relatively narrow predetermined spectral distribution, for example a single-chip LED element that exhibits a single-band emission spectrum with a spectral width often on the order of nanometers (eg 20 nm to 60 nm). is there.

  In a second advantageous embodiment of the invention, the transmission characteristics of the filter element are adjusted electrically. The filter element is a voltage-driven or current-driven element, for example, different currents, current densities or voltages are applied to the filter element, so that the transmission characteristics of the filter element advantageously change clearly. The color of the display illuminated by the light emitting electronic elements according to the invention may be adjusted or changed externally via an external terminal electrically connected to the filter element.

  In particular, the color of a monochrome display or an area color display (eg a partial color self-emitting OLED display or LCD) is adjusted or changed by adjusting the transmission characteristics of the filter element. Partial color self-emitting OLED displays are usually understood as displays that display different colors in different areas of the display. The colors of the different areas are usually fixed and / or defined in each area of the display, for example by the color of the light emitted by the OLED.

  A filter element corresponding to an advantageous improvement of the invention comprises at least one electrochromic material. The electrochromic material has the following transmission characteristics. That is, it has a transmission characteristic that depends on the current injected into the electrochromic material and / or the voltage applied to the electrochromic material.

  The electrochromic material is advantageously selected such that it exhibits a relatively high transmission in the visible spectral region. This permeability can be adjusted electrically. The local maximum or global maximum in electrochromic material permeability can be electrically shifted to a higher or lower wavelength. Shifting the transmission maxima to lower wavelengths results in increased absorption in higher wavelength regions (eg, red or orange spectral region). Correspondingly, shifting the transmission maxima to higher wavelengths results in increased absorption in lower wavelength regions (eg, the blue spectral region).

  The electrochromic material advantageously comprises at least one inorganic material or at least one organic material. Inorganic electrochromic materials include, for example, metal oxides (eg, tungsten oxide). Organic electrochromic materials include, for example, at least one polythiophene or other polymeric material. For organic materials, PEDOT-containing (polyethylenedioxythiophene) is particularly advantageous.

  In another embodiment of the invention, the light emitting elements and the filter elements are integrated in a common structure, preferably a common stack. This facilitates the construction of particularly small and / or compact light-emitting electronic elements.

  In an advantageous refinement of the invention, the light emitting element and / or the filter element are arranged in a housing. This housing comprises, for example, an LED or OLED package, a capsule part and / or a sealing means or consists of an LED or OLED package, a capsule part and / or a sealing means. The sealing means is particularly effective for light emitting elements containing organic light emitting materials. Since organic materials are often very sensitive to moisture or oxidants, it may be advantageous to be protected by sealing means. The housing advantageously protects the light emitting element and / or the filter element. Arranging in a common housing is particularly advantageous for the filter element and the light emitting element.

  In another advantageous embodiment of the invention, the light emitting electronic element comprises an electrical connection lead that is conductively connected to the light emitting element and / or the filter element. This lead wire is conductively connected to an external terminal, whereby electronic (preferably microelectronic) and / or photoelectric elements are operated from the outside. For example, after the electronic device is mounted on a circuit board and / or after the device has been integrated into an application for lighting of an LCD display, for example in an LCD display housing, or lighting of an automobile roof panel.

  The light emitting element and the filter element are operated independently of one another or in common during operation of the light emitting element.

  For the former purpose, the filter element and the light emitting element are preferably electrically isolated from each other and / or have separate means for electrical contact connection.

  For the latter purpose, the filter element and the light emitting element are advantageously electrically connected to each other and / or have a common electrode. This electrode is preferably arranged between the light emitting element and the filter element. This electrode may be arranged in a common stack together with the filter element and the light emitting element. The common electrode is used to actuate the filter element and the light emitting element.

  Further advantages and developments of the invention are explained in connection with the description of the embodiments in accordance with the drawings.

  FIG. 1 shows a schematic cross-sectional view of a first embodiment of a light-emitting electronic device according to the invention.

  The light-emitting electronic element 1 has a window 2 and a first electrode 3 disposed on the window 2. The first electrode 3 is followed by a light emitting layer 4, which is electrically connected to the first electrode 3. The second electrode 5 is disposed on the light emitting layer 4 and is electrically connected to the light emitting layer 4. Furthermore, the capsule part 6 is provided in order to protect a light emitting layer more firmly from the influence of a harmful environment.

  The filter element is arranged on the window 2 in the opposite direction to the light emitting element. The filter element includes a first contact 7 disposed on the window, a filter layer 8 conductively connected to the first contact, and a filter layer disposed on the filter layer. The filter element is electrically conductive with the filter layer. And a second contact 9 connected to the. The second contacts are in turn arranged on the carrier 10.

  The light-emitting element has a light-emitting layer 4 and electrodes 3, 5, which may be formed, for example, corresponding to an OLED structure, and / or the light-emitting layer 4 comprises an organic light-emitting material or an organic light-emitting material It may consist of For example, the light emitting layer may comprise an organic polymer material, such as a polyspiro material.

  The light emitting layer may be arranged in a laminate comprising at least one additional light emitting layer and / or other additional layers. In the case of an organic light-emitting layer, this stack is advantageously formed, for example, as an organic stack additionally comprising a hole transport layer. This hole transport layer advantageously increases the efficiency of light generation in the organic stack, particularly in the light emitting layer, by increasing the efficiency of holes injected into the light emitting layer. In the light emitting layer, electrons and holes recombine to generate light by electroluminescence.

  The carrier 10 and the window 2 each or individually advantageously comprise an essentially permeable and / or electrically insulating material. This is for example a glass material or a flexible substrate material, for example PES (polyether sulfone) or PET (polyethylene terephthalate). The carrier 10 and the window 2 preferably comprise the same material. The window 2 functions as a window for light having a predetermined spectral distribution generated in the light-emitting layer, and functions as a carrier that mechanically stabilizes the light-emitting element structure disposed on the window 2.

  The carrier 10 advantageously functions as a carrier for the filter elements including the contacts 7, 9 and the filter layer 8, and the light emitting element 1 is mechanically corresponding to the light emitting element structure arranged on the filter element carrier 10. Functions as a carrier to stabilize. Particularly preferably, the carrier 10 protects the filter element. Additional protection means (eg sealing means or capsules) may be provided for the filter element. However, this is not shown.

  The electrodes 3, 5 and / or the contacts 7, 9 comprise, for example, a transparent material or consist of a transparent material. This is preferably a TCO material (transparent conductive oxide), for example ITO (indium tin oxide).

  The capsule part 6 is made of a suitable material. This is for example a suitable sealing material for organic materials known in the area of organic light emitting devices.

At least one inorganic electrochromic material filter layer 8 is preferably includes, for example, or consists of WO _3.

  Light having a predetermined spectral distribution generated through electroluminescence in the light emitting layer 4 is emitted through the electrode 3, the window 2 and the first contact 7, the filter layer 8, the second contact 9 and the carrier 10. By applying a voltage to the filter layer 8, a current injected into the filter layer 8 is generated, and the transmission characteristics of the filter material are changed. This change in transmission characteristics results in a change in the spectral distribution of the light 11 emitted by the electronic element 1.

  Advantageously, the light of the predetermined spectral distribution is white light or other color light having a suitably broad spectral distribution. White light can be obtained, for example, by mixing light of different wavelengths emitted by a suitable chromophore provided in an organic light emitting material. In the case of polyspiro materials emitting in the blue wavelength region, red and green chromophores are integrated into the copolymer structure and the white light emission of the light-emitting element can be achieved by mixing these basic colors (eg red, green and blue). Is realized.

  The spectral distribution and / or color of the light emitted by the electronic element is affected by electrically changing or adjusting the transmission characteristics of the filter material.

  The intensity of light emitted by the electronic element is affected by the proper formation of the filter element. In particular, the thickness of the filter layer 8 determines the absorption of light and thus the intensity transmitted through the filter element. In this way, the filter element is tailored to the specific needs of various embodiments of light emitting electronic elements.

  The intensity of light of a given spectral distribution is also affected by changing the current density at which the light emitting element is driven. Reducing the current density usually corresponds to reducing the intensity of light generated in the light emitting layer. In this way, the intensity of light emitted by the electronic element is changed.

  The light emitting element and the filter element are actuated independently by electrodes 3, 5 and contacts 7, 9, respectively. The contacts 7 and 9 and the electrodes 3 and 5 are insulated from each other by the window 2. The brightness and color coordinates of the light 11 emitted by the electronic element 1 can be adjusted or adjusted independently. The brightness is adjusted or adjusted by adjusting the operating current of the light emitting element via the electrodes 3, 5, and the color coordinates are adjusted or adjusted by the filter element via the contacts 7, 9.

  In this embodiment, the light emitting element is formed corresponding to a conventional light emitting electronic device, and the filter element is provided in an external manner, ie for example outside the light emitting element structure. This light emitting element structure is arranged inside the capsule part or on the window of the light emitting element. This provides a relatively high variability in light emitting element applications. This is because the filter element is provided after the manufacture of the light emitting element is completed.

In FIG. 4, the dependence of the WO ₃ containing filter element on the relative transmission T from the wavelength λ is shown quantitatively for two different voltages. This relative permeability is normalized to a value of 1 with a corresponding maximum value in permeability.

Graph 12 shows the permeability of the WO ₃ containing filter element when zero voltage is applied to the contacts 7, 9. The transmission shown in graph 12 has a relatively high value in the visible spectral region above about 0.6 or 0.6, and has a particularly high value in the green or yellow region, about 550 nm. And has a maximum value.

Graph 13 shows the permeability of the WO ₃ containing filter element when a voltage of 5V is applied and current is flowing through the filter element. Compared with graph 12, the transmission in graph 13 is much lower in the visible spectral region, especially in the orange and red spectral regions. For wavelengths above about 600 nm, the transmission is 50% or less. The transmission maximum in graph 13 is located at about 460 nm.

  In the case of essentially pure white light (eg, white light generated by electroluminescence in an organic polyspirocopolymer light-emitting layer with a suitable chromophore) having an appropriate broad spectral distribution, The amount of light transmitted through a filter element having transmission characteristics and transmitted in the green and yellow spectral regions is preferred compared to blue and red outside the visible spectral region. As a result, the initial essentially pure white color that is transmitted has a white color with a greenish, yellowish hue.

The color of light emitted by an electronic device (for example, the electronic device shown in FIG. 1) is such that 0 voltage is applied to the WO ₃ electrochromic filter layer 8 having transmission characteristics as shown in FIG. Is represented by point 120 in the CIE chromaticity diagram shown in FIG. Point 120 has coordinates x = 0.31 and y = 0.39. This corresponds to white light with a yellow or green tint.

  Pure white light is indicated by white dots 14. This has the coordinates x = y = 1/3 in the CIE chromaticity diagram which is limited by the boundary 15. The colors on the interior region of the triangle 150 or the border of the triangle 150 are mixed by using two or three colors with coordinates corresponding to the corners of the triangle.

  When the voltage rises from 0V to 5V, the light emitted by the electronic element changes as indicated by the arrow, and its color coordinates continuously from point 120 through point 121, point 122, and point 123. Point 130 is reached. Point 130 has color coordinates x = 0.26 and y = 0.33 and appears as white with a turquoise hue. This is due to the higher absorption in the red and orange spectral regions, corresponding to graph 13.

The color coordinates of the light emitted by the electronic element 1 can be changed according to the invention. When an electronic device according to the invention is used as an ambient light source, the color of the ambient light is adjusted. For example, when WO ₃ is used as an electrochromic filter material, the color of the initial white light emitted by the emissive layer is changed from white with a relatively cold blue-green hue to a relatively warm yellow or green Changes to white with a hue of V, and vice versa. Thus, a single ambient light emitting electronic device is used to produce different ambient light due to the atmosphere. Cold light, for example, is particularly useful as workplace lighting and increases employee work efficiency. On the other hand, warm light is rather suitable for a leisure atmosphere.

  Since the transmission characteristics of the filter element are changed electrically and reversibly, the light emitted by the element can be switched between different colors and / or continuously adjusted. The intensity of light emitted by the electronic element is also additionally influenced via the operating current of the light emitting element. As a result, the light emitting element can be adjusted in color and dimmed.

  FIG. 2 shows a schematic cross-sectional view of a second embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. Compared to the embodiment of FIG. 1, in the embodiment corresponding to FIG. 2, the light-emitting layer 4 and the filter layer 8 are integrated in a common stack. As a result, the light emitting device is manufactured in a small and compact shape.

  The filter layer 8 and the light emitting layer 4 may be formed separately from each other and may be combined after completion of each manufacture. An insulating layer 16 is disposed between the light emitting layer and the filter layer, which electrically insulates the electrodes 3 and 5 and the contacts 7 and 9 from each other. The light emitting element and the filter element are thus actuated separately.

  The insulating layer 16 comprises or consists of, for example, silicon oxide (SiOx) or titanium-silicon oxide (TiSiOx), where x is preferably a value, particularly preferably a positive value, and the condition 1 ≦ x ≦ 4 is satisfied.

  The laminate is mechanically stabilized by the window 2 and protected by the capsule part 6.

  By integrating the filter element and the light emitting element in a common laminate, it becomes easy to protect the filter element and the light emitting element by a common protection means, for example, the capsule portion 6.

  FIG. 3 shows a schematic cross-sectional view of a third embodiment of the present invention. This embodiment is similar to the embodiment shown in FIGS. In the embodiment of FIG. 3, the common electrode 17 is disposed between the filter layer 8 and the light emitting layer 4 and is conductively connected thereto. The light emitting element is operated by the second electrode 5 and the common electrode 17. The transmission characteristics of the filter element can be changed by applying an electrode to the filter element via the common electrode 17 and the second contact 9. The difference in electrical potential between the common electrode 17 (eg, the anode of an organic light emitting diode structure) and the contact 9 is adjusted by appropriately changing the electrical potential at the contact 9.

  A light emitting device corresponding to this embodiment is formed with and operated by three external electrodes. Two for the light emitting elements are connected to the second electrode 5 and the common electrode 17, and one terminal is connected to the second contact 9 to electrically adjust the transmission characteristics of the filter element. Compared to the embodiment of FIGS. 1 and 2, one external electrical terminal, ie the terminal connected to the first contact 7 shown in FIGS. 1 and 2, is omitted.

  FIG. 6 shows a schematic cross-sectional view of a fourth embodiment of a light-emitting electronic device according to the present invention.

  The light emitting electronic device has at least one LED chip 18. This preferably comprises at least one semiconductor material, particularly preferably a III-V-semiconductor material and / or a crystalline semiconductor material, which LED chip is arranged in the recess 24 of the housing 22. . This housing comprises, for example, a plastic material. The LED chip is electrically connected to the leads 20 and 21 by appropriately attaching and / or fixing the LED chip on the lead 20 by, for example, a conductive adhesive or soldering, and electrically connecting the bonding wire 23 to the lead 21. Connected to sex. The wall 25 of the recess 24 is completely or partially covered by a reflection enhancing material, such as metal. Accordingly, the light emitting element may be formed in accordance with a surface mount device (SMD) and can be mounted on a circuit board by, for example, leads 20 and 21.

  Lights 11 a and 11 b generated in the LED chip 18 by electroluminescence are emitted by the element 1 after passing through the filter element 19. The filter element comprises contacts 7, 9 and a filter layer 8 comprising, for example, an electrochromic material. The light 11b is reflected by the wall 25 of the recess 24 before entering the filter element. The transmission characteristics of the filter layer 8 are electrically adjusted via leads 26 and 27 that are conductively connected to the filter layer.

  The light of the predetermined spectral distribution produced by the light emitting element is advantageously essentially white or a mixed color.

  White light is generated, for example, by suitably mixing light emitted by a plurality of LED chips, which are advantageously arranged in a common housing and / or emitting in the spectral region of red, green and blue, for example. For LED chips, it is particularly advantageous to have separate leads that allow individual operation of each LED chip.

  White light is luminescence from a first wavelength of light emitted by a single LED chip into longer wavelength light by a suitable luminescence conversion material (eg, a phosphor material) disposed in the recess. It is also generated through sense conversion. Mixing these two lights results in white light. For this purpose, it is advantageous for LED chips to emit in the blue or ultraviolet spectral region and for light re-emitted by the conversion material is in the yellow or orange spectral region. Is advantageous.

  The filter elements are arranged in layers on the housing 22 of the light emitting element, preferably mechanically fixed. The light emitting element and the filter element are independently actuated by terminals connected to leads 20, 21 and 26, 27, respectively. The recess is partially or completely filled with a protective material (eg silicone) to enhance the protection of the LED chip. If luminescence conversion is to take place, this protective material is advantageously simultaneously formed as a carrier material for the luminescence conversion particles arranged in or on the material.

  The protection scope of the present invention is not limited to the embodiments described above. The invention is realized by combinations of these features, including each new feature and each combination of all the features specifically recited in the claims (even if such features or these features). Combinations of specific configurations are not explicitly recited in the claims or examples).

  In particular, the light-emitting electronic element according to the invention may comprise more than one filter element. The light emitting element may for example be arranged between two layered filter elements, or a plurality of filter elements may be arranged successively in the beam path of light emitted by the light emitting element. Furthermore, the filter material does not have to be provided in layers and is suitably provided by liquids in other shapes, for example with particles of filter material preferably having electrically adjustable filter particle transmission characteristics. May be.

1 is a schematic cross-sectional view of a first embodiment of a light-emitting electronic device according to the present invention. Schematic cross-sectional view of a second embodiment of a light-emitting electronic device according to the present invention Schematic cross-sectional view of a third embodiment of a light-emitting electronic device according to the present invention Diagram of wavelength dependence of filter element transmission for two different voltages A diagram showing, in a CIE chromaticity diagram, the change in the color of light emitted by an electronic device according to the invention as a result of adjusting the transmission characteristics of the filter element. Schematic cross-sectional view of a fourth embodiment of a light-emitting electronic device according to the present invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Light emitting element, 2 Window, 3 1st electrode, 4 Light emitting layer, 5 2nd electrode, 6 Capsule part, 7 1st contact, 8 Filter layer, 9 2nd contact, 10 Carrier, 11 Light, 11a Light, 11b light, 18 LED chip, 19 filter element, 20 lead, 21 lead, 22 housing, 23 bonding wire, 24 recess, 25 wall part, 26 lead, 27 lead

Claims (14)

A light emitting electronic device,
At least one light emitting element for emitting light having a predetermined spectral distribution;
Including at least one filter element disposed in a beam path of light having a predetermined spectral distribution;
The transmission characteristic of the filter element with respect to light having a predetermined spectral distribution is of a type that defines the spectral distribution of light emitted by the light emitting element
A light-emitting electronic device, wherein the transmission characteristics of the filter element can be adjusted during operation of the light-emitting electronic device.   The element of claim 1, wherein a color of light emitted by the element is adjustable by adjusting a transmission characteristic of the filter element.   The device of claim 1, wherein the light emitting element comprises at least one photoelectric element.   The device of claim 1, wherein the light emitting element comprises at least one organic light emitting material.   The device of claim 1, wherein the light emitting element comprises an organic light emitting diode structure.   The element of claim 1, wherein the transmission characteristics of the filter element are electrically adjustable.   The device of claim 1, wherein the filter element comprises at least one electrochromic material.   The device of claim 7, wherein the electrochromic material comprises at least one inorganic material.   The element according to claim 8, wherein the inorganic material is tungsten oxide.   The device of claim 7, wherein the electrochromic material comprises at least one organic material.   The element according to claim 1, wherein the light emitting element and the filter element are integrated in a common laminate.   The element of claim 1, wherein the light emitting element and the filter element are disposed within a common housing.   The device of claim 1, wherein the light emitting element and the filter element are operated independently of each other during operation of the light emitting device.   The element according to claim 1, wherein the light emitting element and the filter element are operated in common during operation of the light emitting element.

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