DE102007029566A1 - Method for manufacturing electrophoretic indicator, involves providing electrode arrangement with two electrodes, where latter electrode is structured such that individual pixel is controlled by controlling unit - Google Patents

Abstract

The method involves providing an electrode arrangement (100) with two electrodes (102,104). The latter electrode is structured such that an individual pixel is controlled by a controlling unit (114). The electrode arrangement is inserted with a radiation (136). The radiation hit by the transparent electrode through cavities. Independent claims are also included for the following: (1) an electrophoretic indicator, which has electrode arrangement (2) a document, particularly a worth or a safety document, which has an electrophoretic indicator.

Description

The The invention relates to a method for producing an electrophoretic Display device, an electrophoretic display device and a document, in particular a value or security document.

deposited colored particles in a microcapsule or a microsphere so that the particles can move by applying an electric field. An electrophoretic display device may also be configured so that electrically charged particles of one color can move in a liquid of a different color within an embossed microstructure. Corresponding electrophoretic display devices are known, inter alia EP 1 500 970 A1 . DE 60107396 T2 . DE 69824746 T2 and WO / 2006/103605 ,

Of the The invention is based on the object, a improved process for producing an electrophoretic Display device, an electrophoretic display device and a document, in particular a value or security document create.

The The objects underlying the invention are each with the Characteristics of the independent claims solved. Embodiments of the invention are in the dependent Claims specified.

According to the invention a method for producing an electrophoretic display device created, which of an electrode assembly with a first Electrode and a second electrode, the second Electrode is structured so that individual pixels by a control unit are controllable, wherein at least one of the first and second electrodes is transparent. There are cavities between the first and second electrodes arranged, for example in the form of microcapsules, in particular Microspheres or microcups, each containing a medium include electrophoretic particles. The electrophoretic Particles are black or colored, for example.

A first subset of the cavities is arranged so that they is usable for generating the pixels, whereas a second Subset of cavities is arranged so that they pass through the control unit is not controllable. Due to the static Distribution of electrophoretic particles in the cavities For example, the second subset has a fixed one Gray or color value, which also affects the electrode arrangement does not change. This is due to the fact that the cavities the second subset outside of by controlling the Elektrodenan order by the control unit generated electric field are arranged, or that in the area of the cavities The second subset of producible electric field is not sufficient Strong is the electrophoretic particles in the cavities align the second subset.

The Electrode arrangement is acted upon by a radiation which the transparent electrode passes through the cavities. As a result, are facing to the transparent electrode Inside of the cavities located electrophoretic Particles rendered ineffective. This becomes the unchanging one Gray or color value of the electrophoretic particles of the Cavities of the second subset is generated permanently, reduced or eliminated.

The Invention is particularly advantageous because a precise alignment the structured electrode is not required on the cavities is to create a high quality electrophoretic display device manufacture. This is due to the fact that the cavities the second subset, for example, below the interstices between adjacent partial electrodes of the patterned electrode are arranged due to the ineffectiveness of their electrophoretic Particles which are located at the transparent electrode facing Inside of the cavities are none display permanent gray or color value. In contrast, the contrast the producible by the cavities of the first subset Pixels due to the ineffectiveness of the electrophoretic particles not or not significantly affected, as in the cavities typically a very large number of particles in the range of some Thousand or millions are available. Because the cavities the first subset controlled by the electrode assembly can be located in these cavities electrophoretic Medium mixed by movement of the electrophoretic particles so that a relatively small number are rendered ineffective electrophoretic particles for imaging not or not significant.

According to one embodiment of the invention, the partial electrodes of the structured electrode are formed in the form of a matrix or segment. The segments can have different sizes and in principle arbitrarily - depending on the content to be displayed - be arranged. The arrangement of the cavities, on the other hand, can be independent. In particular, the cavities can be arranged in a single layer in two dimensions. The cavities may also be distributed three-dimensionally between the electrodes of the electrode arrangement, either randomly distributed or in a crystal lattice arrangement, such as, for example, cubic pri mitiv, cubic or hexagonal closest packing. This has the advantage that the electrode arrangement with the cavities located therebetween can be produced particularly inexpensively, since it is not necessary to align the structured electrode with the cavities.

To an embodiment of the invention, the inaccuracy takes place of the electrophoretic particles in that the electrophoretic particles be faded by the radiation. For example, the electrophoretic particles coated with a paint by the radiation is faded.

To An embodiment of the invention is the electrophoretic particles around molecules passing through the radiation will be fragmented. By fragmenting lose the electrophoretic particles of their color. For example the molecules are transparent or due to fragmentation White.

To an embodiment of the invention leads the Particle radiation causes intra- or intermolecular reactions. In the case of an intramolecular reaction, the radiation to the Example, encourage a rearrangement or fragmentation so that Shape and or structure of the molecule are changed. In an intermolecular reaction, the radiation can be chemical Reactions hiss the particle and the molecules in it immediate environment, for example oxidation or addition reactions.

To An embodiment of the invention is the radiation around ultraviolet (UV) light, visible (VIS) light and / or infrared (IR) light. As inventive Radiation sources can be, for example, halogen lamps, UV lamps, arc lamps, Mercury lamps, high pressure lamps, gas discharge lamps, barrier discharge lamps, Plasma, thermal radiator, cathode ray tube with Converter layer, diodes and / or laser can be used. According to the invention filters, diffractive or reflective optics are used, so that individual wavelengths, wavelength ranges or continuous spectra of the light sources to Ausblei chung be used. The radiation dose to act on the electrode arrangement is chosen so that only the top layer or few of the upper layers of electrophoretic particles that on the inner side of the transparent electrode adjacent the Cavities are located, made ineffective. In deeper located layers to be located electrophoretic particles on the other hand remain as intact as possible, so that only a total a low percentage of, for example, at most 5% the electrophoretic particles per cavity ineffective is done.

To An embodiment of the invention is the electrode arrangement before the exposure to the radiation so controlled that the black or colored electrophoretic particles from the transparent Electrode be moved away. So there are only black or colored electrophoretic particles on the transparent electrode facing insides of the cavities of the second subset, which are not controllable. Because the black or colored electrophoretic particles in the cavities of the second Subset when exposed to the radiation relatively far are located away from the transparent electrode, are substantially only the unwanted black or colored electrophoretic Particles in the cavities of the second subset ineffective made.

To An embodiment of the invention is the electrode arrangement energized after exposure to the radiation to the in the Cavities of the first subset electrophoretic Particles move, causing a redistribution of the electrophoretic Particle comes. As a result, the medium is mixed, so the due the radiation rendered ineffective electrophoretic particles in be distributed to the volume of the medium.

To An embodiment of the invention is the electrode arrangement activated both before and after exposure to the radiation, around the electrophoretic particles in the cavities of the to move first subset. In this case, for example, the electrode arrangement before the exposure to the radiation so controlled that the black or colored electrophoretic particles from the transparent Electrode are moved away, whereas the electrode assembly is energized after exposure to the radiation so that the black or colored electrophoretic particles in one be moved in the opposite direction, so as to mix the medium.

To an embodiment of the invention are in the medium next to the first electrophoretic particles, which are black or a first color, second electrophoretic particles of opposite Charge present, which are white, for example.

In a further aspect, the invention relates to an electrophoretic display device having an electrode arrangement with a first electrode and a second electrode, wherein the second electrode is structured so that individual pixels can be controlled by a control unit, between the first and the second electrode disposed cavities, the a medium with first electrophoreti include a first subset of the cavities for generating the pixels, and a second subset of the cavities is arranged so that they are not controlled by the control unit, wherein the cavities of the second subset in each case below one between adjacent sub-electrodes the second electrode formed lateral distance.

A such electrophoretic display device may be used as an intermediate be prepared, which by the subsequent admission with the radiation is still to improve the quality the generatable with the electrophoretic display device To increase ads. After exposure to the radiation is the electrophoretic display device according to the invention characterized in that a part of the electrophoretic particles is faded or fragmented.

invention Electrophoretic display devices are suitable in principle for any application, such as for electronic paper, such as e-books, digital picture frames, as a display an electronic device, such as a mobile phone, or similar.

In In another aspect, the invention relates to a document, in particular a value or security document, with an electrophoretic display device, which is formed according to the invention. At the document For example, it may be an ID document, in particular a Identity document, such as an identity card, passport or company card, a credential, a credit card or the like. The document can be paper and / or plastic based be educated. In particular, the document may also to trade a chip card.

in the Further, embodiments of the invention will be referred to explained in more detail on the drawings. Show it:

1 an embodiment of an electrophoretic display device according to the invention,

2 the electrophoretic display device of 1 after exposure to radiation,

3 a flow chart of an embodiment of a method according to the invention,

4 a block diagram of an embodiment of a document according to the invention.

elements the following figures, which correspond to each other, are with them Reference number marked.

The 1 schematically shows a portion of an electrode assembly 100 an electrophoretic display device in a version as a segment display. The electrode arrangement 100 has a first electrode 102 that is transparent. Through the electrode 102 Thus, a display generated by the electrophoretic display device becomes visible to a viewer. To the electrode assembly 100 further includes a second structured electrode 104 , which in several partial electrodes 106 . 108 . 110 , ... is subdivided. The individual partial electrodes 106 . 108 . 110 , ... are for example via control lines 112 with a control unit 114 connected. Through the control unit 114 can be between the electrode 102 and the partial electrodes 106 . 108 . 110 , ... different voltages are applied so that corresponding electric fields in the area between the electrode 102 and the respective partial electrodes 106 . 108 . 110 , ... result.

Between the electrode 102 and the electrode 104 There are a large number of cavities, of which in the 1 the cavities 116 . 118 . 120 . 122 and 124 are shown by way of example. The cavities 116 . 118 . 120 . 122 . 124 are spherical in the embodiment considered here. However, the cavities can also have a different spherical shape or they can be designed, for example, as microcups. The cavities are each with an electrophoretic medium 126 filled. In the medium 126 are electrophoretic particles 128 that have a black color, and electrophoretic particles 130 that are white. The electrophoretic particles 128 and 130 have different electrical charges. For example, the electrophoretic particles 128 positively charged while the electrophoretic particles 130 are negatively charged.

Suitable materials for the electrophoretic medium 126 and for the electrophoretic particles 128 . 130 are, for example, from the EP 1 500 970 A1 known. For example, the particles have 128 . 130 a size in the micrometer range or they are molecules. In the latter case, the cavities can have a very large number of particles 128 . 130 involve, on the order of a few thousand to billions of such particles.

The 1 For the sake of clarity, only the outermost layers of the particles are shown 128 . 130 on the inner walls of the cavities. The cavities 116 . 118 . 120 . 122 . 124 , ... each have the transparent electrode 102 facing insides 132 closer to the electrode 102 lie as the on the opposite side of the cavities located inside pages 134 ,

The cavities 116 . 118 . 120 . 122 . 124 , ... are in the space between the electrode 102 and the electrode 104 preferably arranged directly adjacent to one another in a matrix. The structuring of the electrode 104 is not congruent with the rows and columns of this array. In this case, the number of partial electrodes 106 . 108 . 110 , ... be larger or smaller than the number of cavities. Further, the rows and columns, in which the sub-electrodes are arranged, ge compared to the matrix in which the cavities are arranged, be offset and / or have different rows and / or column spacing. Furthermore, electrode and cavity arrangements can have completely different structures, for example cubic packing and hexagonal closest packing. In a segment display, the electrode arrangement may also be completely different from the cavity arrangement. Instead of a two-dimensional arrangement, as in the 1 and 2 As shown, the cavities may also be distributed three-dimensionally randomly or in a regular grid arrangement. This has the advantage that the electrode arrangement 100 With the intervening cavities can be produced particularly inexpensive, since a precise alignment of the patterned electrode on the cavities is not required.

As the structuring of the electrode 104 So is not congruent with the arrangement of the cavities, some of the cavities are in areas within which no or only a weak electric field by driving the sub-electrodes by the control unit 114 which is not responsible for the movement of the particles 128 . 130 in the medium 126 is sufficient. In the section of the electrode arrangement considered here 100 this affects the cavities 118 and 122 extending below the interstices 135 between the partial electrodes 106 and 108 respectively. 108 and 110 are located.

The cavities 116 . 120 and 124 So can from the control unit 114 are driven to produce a black or white pixel, whereas the cavities 118 and 122 can not be fully controlled. As a result, whatever the between the electrode 102 and the sub-electrode applied voltages, the static distribution of the particles 128 . 130 within the cavities 118 . 122 remains essentially unchanged. This has the consequence that the cavities 118 . 122 or subsets of these cavities permanently provide an invariable gray value, due to the statistical distribution of the particles 128 . 130 results.

In the section of the electrode arrangement considered here 100 So are between the by controlling the cavities 116 . 120 and 124 can be generated pixels transition areas through the cavities 118 and 122 be formed; These transition areas between the pixels each have an unchangeable gray value. The transition regions of constant gray level lead to an impairment of the brilliance and the reproduction quality of a display output via the display device.

To remedy this technical problem, the electrode assembly is irradiated 136 on the transparent electrode 102 applied. The radiation 136 is from a radiation source 138 delivered, which may be, for example, UV radiation or laser radiation.

If a particle 128 is acted upon by a sufficient dose of radiation, this is made ineffective, for example, by the color of the particle 128 is bleached, or by the particle 128 fragmented and destroyed. The dose of radiation 136 is therefore chosen so that these after passing through the electrode 102 in the cavities just enough to on the insides 132 located particles 128 to render ineffective. This is to ensure that only those close to the electrode 102 arranged particles 128 be made ineffective, but not more distant particles 128 , for example, deeper inside the cavities or on the insides 134 are located. By exposure to the radiation 136 especially the two in the cavities 118 and 122 located particles 128.1 and 128.2 this is done by fragmentation in the embodiment considered here.

Before exposure to the radiation 136 It is beneficial that the particles 128 from the electrode 102 be moved away so as to be against the subsequent incident radiation 136 to protect. In the embodiment considered here, this is for the cavity 124 takes place so that only their white particles 130 on the inside 132 whereas the black particles are 128 on the opposite inside 134 have collected.

The 2 shows the view of 1 after the application of the electrode arrangement 100 with the radiation 136 , Like from the 2 As can be seen, the particles are 128.1 and 128.2 the cavities 118 . 122 due to their fragmentation no longer exist. This has reduced the number of insides 132 arranged Par tikel 128 the cavit th 118 and 122 , which contribute to the permanent gray value, reduced, so that this gray value near white and thus less disturbing.

By exposure to the radiation 136 also become particles 128 at least in the cavities 116 and 120 fragmented, what in the 2 not shown. To the resulting fragments of the insides 132 To transport away, the cavities can 116 and 120 be controlled so that the medium 126 in the cavities concerned by movement of the particles 128 . 130 is mixed. Due to the large number of particles present in the cavities 128 . 130 So is the ineffectiveness of a small part of the particles 128 by exposure to the radiation 136 completely or almost without influence on the contrast with the cavities 116 . 120 and 124 whereas the disturbing permanent gray value in the transition region between the pixels is due to fragmentation of the particles shown by way of example 128.1 and 128.2 has been reduced towards white.

The 3 shows a corresponding flow chart. In the optional step 200 becomes the electrode arrangement (compare electrode arrangement 100 of the 1 and 2 ) is controlled by a control unit so that a predefined image is displayed. For example, the control takes place in such a way that all the pixels are white. This means that the white particles 130 in each of the cavities of the first subset accumulate at the adjacent to the transparent electrode inside of the respective cavity, as for example for in the 1 shown cavity 124 the case is. The static distribution of the particles 128 and 130 in the cavities of the second subset, which can not be controlled by the electrode arrangement, this does not change, so that transition areas with a medium, constant gray value are located between the white image pixels.

In the step 202 the electrode arrangement is then exposed to radiation which reaches the cavities of the first and second subsets through the transparent electrode of the electrode arrangement. Thereby the black particles (particles 128 , especially the particles 128.1 and 128.2 in the 1 ) in the cavities of the second subset, which are close to the transparent electrode, rendered wholly or partly inactive by the radiation, for example by being bleached or destroyed by fragmentation.

Upon reaching a predetermined maximum radiation dose, the radiation source is turned off and in the optional but preferred step 204 For example, the electrode assembly may be redirected by the control unit to the particles 128 . 130 to move in the cavities of the first subset, so that the medium is mixed. As a result, particles which have been made inactive or their fragments are possibly distributed in the medium due to the action of the radiation in the cavities of the first subset.

The 4 shows a block diagram of a document 303 This is, for example, a value or security document, in particular an ID document or a means of payment, such as a credit card. The document 303 includes an electrophoretic display device according to the invention 301 that the embodiment of the 1 and 2 equivalent. The control unit 314 is here designed as a driver, by an integrated circuit 340 that in the document 303 embedded, can be controlled. In the integrated circuit 340 are for example image data 342 a picture or a sequence of pictures. By controlling the control unit 314 through the integrated circuit 340 can the image data 342 over the display device 301 be reproduced. For example, the image data includes 342 one or more views of a carrier of the document 303 to enable authentication.

100

electrode assembly

102

electrode

104

electrode

106

Partial electrode

108

Partial electrode

110

Partial electrode

112

drive line

114

control unit

116

cavity

118

cavity

120

cavity

122

cavity

124

cavity

126

medium

128

particle

128.1

particle

128.2

particle

130

particle

132

inside

134

inside

135

gap

136

radiation

138

radiation source

300

electrode assembly

301

display device

303

document

314

control unit

340

integrated circuit

342

image data

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1500970 A1 [0002, 0030]
• - DE 60107396 T2 [0002]
• - DE 69824746 T2 [0002]
• - WO 2006/103605 [0002]

Claims (14)

Process for producing an electrophoretic display device comprising the following steps: - providing an electrode arrangement ( 100 ; 300 ) with a first electrode ( 102 ) and a second electrode ( 104 ), wherein the second electrode is structured ( 106 . 108 . 110 , ...) that individual pixels are controlled by a control unit ( 114 ; 314 ), wherein at least one of the first and second electrodes is transparent, and with cavities arranged between the first and second electrodes ( 116 . 118 . 120 . 122 . 124 , ...), each one medium ( 126 ) with first electrophoretic particles ( 128 ), wherein the first electrophoretic particles are black or have a first color, wherein a first subset ( 116 . 120 . 124 , ...) of the cavities serves to generate the pixels, and a second subset ( 118 . 122 , ...) of the cavities is arranged so that they are not controllable by the control unit, - exposure of the electrode assembly with a radiation ( 136 ), which impinge through the transparent electrode on the cavities, so that at the transparent electrode facing inner sides ( 132 ) the first electrophoretic particles ( 128.1 . 128.2 ) be made ineffective. The method of claim 1, wherein the radiation the first electrophoretic particles are faded. The method of claim 1, wherein the first electrophoretic particles are molecules, which are rearranged or fragmented by the radiation or be chemically reacted with other molecules. The method of claim 1, 2 or 3, wherein it is at the radiation to ultraviolet (UV) light, visible (VIS) Light and / or infrared (IR) light is, preferably one of the following radiation sources halogen lamps, UV lamps, arc lamps, Mercury lamps, high pressure lamps, gas discharge lamps, barrier discharge lamps, plasma, thermal radiator, cathode ray tube with converter layer, Diodes and / or lasers are used, and preferably Filter, diffractive or reflective optics are used, so that single wavelengths, wavelength ranges or continuous spectra of the radiation source for application the electrode assembly can be used. Method according to one of the preceding claims, wherein prior to the application of the electrode arrangement with the radiation the electrode assembly is driven so that the first electrophoretic Particles of the first subset of the cavities of the transparent electrode are moved away. Method according to one of the preceding claims, wherein after the application of the electrode arrangement with the radiation the electrode assembly is driven so that the first electrophoretic Particles of the first subset of cavities redistributed to mix the medium. Method according to one of the preceding claims, wherein the electrode assembly prior to exposure to the radiation and after exposure to the radiation for redistribution of the first electrophoretic particles in the cavities of the first Subset is controlled. Method according to one of the preceding claims, wherein the medium second white electrophoretic particles ( 130 ) having a charge opposite to the first electrophoretic particles. Electrophoretic display device with - an electrode arrangement ( 100 ; 300 ) with a first electrode ( 102 ) and a second electrode ( 104 ), wherein the second electrode is structured so that individual pixels by a control unit ( 114 ; 314 ), - between the first and the second electrode disposed cavities ( 116 . 118 . 120 . 122 . 124 , ...), which is a medium ( 126 ) with first electrophoretic particles ( 128 ), wherein a first subset ( 116 . 120 . 124 , ...) of the cavities serves to generate the pixels, and a second subset of the cavities ( 118 . 122 , ...) is arranged so that they are not controllable by the control unit, wherein the cavities of the second subset in each case below a formed between adjacent sub-electrodes of the second electrode lateral gap ( 135 ) are located. An electrophoretic display device according to claim 9, wherein a part of the first electrophoretic particles faded or fragmented. An electrophoretic display device according to claim 10, wherein the faded or fragmented portion of the first electrophoretic particles of the second subset of the cavities is located on the insides (FIG. 132 ) of the cavities of the second subset is located. An electrophoretic display device according to claim 9, 10 or 11, wherein the medium comprises second white electrophoretic particles ( 130 ) having a charge opposite to the first electrophoretic particles. Electrophoretic display device according to of claims 9 to 12, wherein the cavities between The first and second electrodes are statistically distributed three-dimensionally or arranged in an at least two-layer grid arrangement are. Document, in particular value or security document, with an electrophoretic display device according to one of Claims 9 to 13.