US20220057335A1

US20220057335A1 - Optical state monitor with an indicator-sensor

Info

Publication number: US20220057335A1
Application number: US17/491,796
Authority: US
Inventors: Paul Atkinson; John Rilum; Edzer Huitema
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-01-17
Filing date: 2021-10-01
Publication date: 2022-02-24
Also published as: US20190219514A1; US10613035B2; US20200309712A1; US11204331B2

Abstract

In one configuration, an optical state monitor is augmented or comprises one or more indicator-sensors that self-generate different optical profiles (signatures) in response to an item or its environment; wherein wherein the indicator-sensors cooperate with the electromagnetic radiation detectors of the optical state monitor in the detection and determination of the condition(s) of the item or its environment, or of the indicator-sensor and its environment. Of particular interest are indicator-sensors that are thin, flexible, patternable and printable (or otherwise deposited) as films or additive layers to electromagnetic detection layers or other structures of the optical state monitor.

Description

RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application No. 63/086,175, filed Oct. 1, 2020 and entitled “An Optical State Monitor with an Indicator-Sensor”. This application is also a continuation-in-part of U.S. patent application Ser. No. 16/840,409 filed Apr. 5, 2020 which is a continuation of U.S. patent application Ser. No. 15/873,132, filed Jan. 17, 2018, now U.S. Pat. No. 10,613,035, and entitled “Optically Determining the Condition of a Good”. This application is also a continuation-in-part to U.S. patent application Ser. No. 15/368,622, filed Dec. 4, 2016, and entitled “Optically Determining Messages on a display,” which claims priority to U.S. provisional patent application No. 62/263,053, filed Dec. 4, 2015 and entitled “Optically Determining Messages on a Display;” to U.S. provisional patent application No. 62/341,768, filed May 26, 2016 and entitled “Systems and Methods for Independently Determining Visible Messages on Intelligent Visual Devices;” and to U.S. provisional patent application No. 62/365,108, filed Jul. 21, 2016 and entitled “Devices, Systems, and Methods for Optical Detection of Visual Displays;” all of which are incorporated herein by reference as if set for in their entirety. This application is also related to U.S. patent application Ser. No. 14/927,098, filed Oct. 29, 2015 and entitled “Symbol Verification for an Intelligent Label Device,” which is also incorporated herein as if set forth in its entirety.

FIELD OF THE INVENTION

The field of the present invention is the design, manufacture, and use of electronic sensors for detecting electromagnetic radiation from a good, and using the detected radiation to determine a quality of the good.

BACKGROUND

U.S Pat. No. 10,613,035, entitled “Optically Determining the Condition of Goods,” teaches means and methods of optically determining the condition of a good wherein electromagnetic radiation illuminates/interrogates the good, an optical state monitor detects the reflected or transmitted radiation by or through the good at one or more sites of the good, and uses the detected radiation to determine the optical state of the good; wherein the determined optical state of the good is indicative of a condition, characteristic, quality, utility of the good etc. Among their benefits are their ability to autonomously and cost-effectively monitor large areas of a good or environment (multiple sites) that may be subject to modest and non-uniform changes.
In some applications it is desirable to optically detect/determine changes in one or more conditions in a proximate material(s) that correlates to the state of a good, or more generally an item, or an environment: wherein changes in the optical state of the material are different from those of the item or environment or may be easier to detect/determine (e.g., given the illuminating/interrogating radiation).

SUMMARY OF THE INVENTION

Disclosed herein are optical state-monitors augmented with or comprising indicator-sensors that comprise a material or combination of materials that self-generate different optical profiles (signatures) in response to an item or its environment; wherein the indicator-sensors cooperate with the electromagnetic radiation (e.g., light) detectors of the optical state monitor in the detection and determination of the condition(s) of the item or its environment, or of the indicator-sensor and its environment. Of particular interest are indicator-sensors that are thin, flexible, patternable and printable (or otherwise deposited) as films or additive layers to electromagnetic detection layers or other structures of the optical state monitor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a display in accord with the present invention.

FIG. 2 is an illustration of a display in accord with the present invention.

FIGS. 3A and 3B are illustrations of a display in accord with the present invention.

FIG. 4 is an illustration of a display in accord with the present invention.

FIG. 5 is an illustration of a display in accord with the present invention.

FIG. 6 is an illustration of a display in accord with the present invention.

FIG. 7A is a diagram of an emissive display with the photosensitive detector in front of display in accord with the present invention.

FIG. 7B is a diagram of an emissive display with the photosensitive detector behind the display in accord with the present invention.

FIG. 8 is a diagram of an emissive display using a backlight and a shutter, like an LC layer with the detector placed on top of the display in accord with the present invention.

FIG. 9 is a block diagram of an intelligent label in accord with the present invention.

FIG. 10 is illustrates a light-sensing in-cell touch integrates optical sensors into the thin film transistor layer in accord with the present invention.

FIG. 11 is a cross-section of readout and photo a-Si TFT with opening in black matrix in accord with the present invention.

FIG. 12 is a circuit diagram of four LCD pixels and one sensor circuit in accord with the present invention.

FIG. 13A is a schematic diagram of AMOLED pixel circuit in accord with the present invention.

FIG. 13B is a timing diagram for a AMOLED pixel circuit in accord with the present invention.

FIG. 14 is measured photo-current under varying light intensity for an a-Si TFT with gate shorted to source and W\L=36 μm/6 μm in accord with the present invention.

FIG. 15 is a-Si:H optical feedback pixel circuit in accord with the present invention.

FIG. 16 is a reflective display using a light source (e.g. a backlight) and an integrated optical sensor in accord with the present invention.

FIG. 17 is a reflective display in accord with the present invention.

FIG. 18 is an emissive display in accord with the present invention.

FIG. 19 is an emissive display in accord with the present invention.

FIG. 20 is a shutter display with an integrated optical sensor in accord with the present invention.

FIG. 21 is a reflective display in accord with the present invention.

FIG. 22 is a reflective display in accord with the present invention.

FIG. 23 is a reflective display in accord with the present invention.

FIG. 24 is a reflective display with shutter in accord with the present invention.

FIG. 25 is a reflective display with shutter in accord with the present invention.

FIG. 26 is a reflective display with shutter in accord with the present invention.

FIG. 27 is a reflective display with shutter in accord with the present invention.

FIG. 28 is a reflective display with shutter in accord with the present invention.

FIG. 29 is a reflective display with shutter in accord with the present invention.

FIG. 30 is a verifiable display in accord with the present invention.

FIG. 31 is an alphanumeric display in accord with the present invention.

FIG. 32 is a verifiable display in accord with the present invention.

FIG. 33 is a back lit display with a shutter in accord with the present invention.

FIG. 34 is a verifiable display in accord with the present invention.

FIG. 35 is a verifiable display in accord with the present invention.

FIG. 36 is a verifiable display in accord with the present invention.

FIG. 37 illustrates measurements of a verifiable display in accord with the present invention.

FIG. 38 illustrates measurements of a verifiable display in accord with the present invention.

FIG. 39 illustrates measurements of a verifiable display in accord with the present invention.

FIG. 40 illustrates measurements of a verifiable display in accord with the present invention.

FIG. 41 is a switching curve of a pixel that is switched from white to black and back to white again in accord with the present invention.

FIG. 42 is a switching curve of a pixel that is switched from white to black and back to white again in accord with the present invention.

FIG. 43 shows a side view and a top view of an optical state monitor in accordance with the present invention

FIG. 44 shows a side view of an optical state monitor in accordance with the present invention

FIG. 45 shows a top view of an optical state monitor in accordance with the present invention

FIG. 46 shows a top view of an optical state monitor in accordance with the present invention

FIG. 47 shows a side view of an optical state monitor in accordance with the present invention

FIG. 48 shows a top view of an optical state monitor in accordance with the present invention

FIG. 49 shows a planar view of an optical state monitor in accordance with the present invention

FIG. 50 shows a side perspective view of an optical state monitor in accordance with the present invention

FIG. 51 is a method of using an optical state monitor in accordance with the present invention.

FIG. 52 is a method of using an optical state monitor in accordance with the present invention.

FIG. 53 is a method of using an optical state monitor in accordance with the present invention.

FIG. 54 is an exemplary configuration of a vertically integrated (reflection mode) optical state monitor with an indicator-sensor in accordance with the present invention.

FIG. 55 is an exemplary configuration of a vertically distinct (reflection mode) optical state monitor with an indicator-sensor in accordance with the present invention.

FIG. 56 is an exemplary configuration of a laterally integrated (TIR mode) optical state monitor with an indicator-sensor in accordance with the present invention.

FIG. 57 is an exemplary configuration of a vertically integrated optical state monitor with an indicator-sensor for detection of an environmental condition in accordance with the present invention.

FIG. 58 is an exemplary configuration of a optical state monitor with a plurality of indicator-sensors in accordance with the present invention.

DETAILED DESCRIPTION

Messages displayed by bi-stable displays such as electrophoretic displays manufactured by E Ink and certain LCDs (e.g., zenithal bistable and cholesteric) are to varying degrees stable without the continuous application of power. By design, they are however reversible and the displayed messages are therefore subject to accidental or intentional erasure or alteration. It can't be certain therefore whether the displayed information is as intended or otherwise determined (unlike irreversible displays such as those described in U.S. Pat. No. 9,030,724 B2).
Of particular interest here are reflective displays that are illuminated with ambient light and read from the same side in reflection. However, the example displays described herein can be extended to other types of displays including, but not limited to, transmissive, transreflective or emissive (e.g. back or front lit) configurations. The inventions described herein cover determination and verification systems for reflective electrophoretic and reflective bistable liquid crystal displays, however, they are also applicable to other types of bi-stable or multi-stable displays and to electro-optic displays in general.
For the purposes of these example descriptions, pixels are single addressable visual elements of the display. In some instances, a pixel may be a ‘dot’ and in others it maybe a shape such as a ‘segment’ used in the formation of a ‘seven segment’ alphanumeric display. Pixels may also be a variety of shapes, symbols or images that are determined by the surface areas of the electrodes used to signal them. A shape of course may be comprised of multiple pixels.
Note that in many applications such as intelligent labels, the density, variety and resolution of the displayed messages is not typical of that required for consumer electronics. As such the messages may be generated using comparatively large pixels in shapes optimized for messages appropriate for the application instead of arrays of much larger numbers of significantly smaller pixels.
As used herein, a message consists of the ‘state’ of one or more pixels. In a monochrome display for example, a pixel typically has at least two intended states, one each of two distinct colors (e.g. black and white) and depending on the display, a third state which is not one of the distinct colors (e.g., gray or semi-transparent).
The intended state of a pixel may be different from its actual displayed state however due to damage, hardware or software malfunction, loss of power, age, radiation, tampering, being subjected to environmental conditions outside of allowed operating or storage conditions, etc. By extension, an intended message also maybe different from the corresponding displayed message.
The visible state of pixels that make up a message (message pixels), and by extension the visible state of the displayed message, depends on available light (intensity, wavelengths etc.). The perceptibility of a visible message further may depend on other variables that affect its understandability or interpretability. The perceptibility of a message for example, may depend on the contrast between the pixels comprising a message and their areas surrounding them. The clarity and sharpness of the pixels, individually and in combination, may also impact the perceptibility of a message.
Accordingly, a message may have an intended display state, a visible state, and a perceptible state. The displayed state is the state of the message pixels independent of the available light. The displayed state of a message corresponds to what could have been visible to man or machine (observable, seen) if light was available. The visible state is the state of the message pixels visible (by man or machine) with available light. The visible state of a message corresponds to what could be observed (seen) with available light. The perceptible state is the state of a set of message pixels that is understandable or interpretable (by man or machine) with available light. The perceptible state of a message corresponds to what could be understood or interpreted with the available light.
Note that it may be advantageous to determine the states of pixels and messages independent of (without reference to) their intended state (if any). For example, it may be advantageous to know exactly what message was viewable or perceptible even if it wasn't the intended one.
Described herein are devices, methods and systems for verifying and determining displayed messages and their corresponding states, either by human or with automation. And further, for enabling transactions, analytics, monitoring conditions and outcomes, and managing outcomes based on access to, receipt of, and access to information that is verifiable, verified or enhanced by being a product of, a component of, or an outcome of such devices, methods or systems.
The terms ‘verify’ and ‘determine’ may sometimes be used herein interchangeably, particularly in the different context of the users' and systems' perspectives. From a system perspective for example, the term verify typically implies a comparison between a displayed message and a known dataset—e.g. an intended message. The term determine typically implies determining the displayed messages or patterns independent of an intended message. Reference data however may be used to make sense of the patterns. From the user's perspective, verify typically implies being able to confirm ‘what’ the user saw (or thought they saw) and was the basis of their decision or action.
A display device, as defined hereinafter, comprises a display layer and a light detection layer. Devices may also have a light source layer. These functional ‘layers’ may be configured in different ways and in different combinations depending in part on their respective reflective, transreflective or transmissive properties. They may also share common elements (e.g. common electrodes). The term ‘layer’ should be construed broadly to encompass configurations other than those where the functions ascribed to the terms above are literally layered. Of particular interest are configurations where the display layer, light detection layer and light source layer, as well as, the assembled device, are flexible. Devices however, and their components, may also be semi-rigid and rigid. Devices may also include electronics, methods and systems described herein.
The display layer displays the message and may be any of different types including, but not limited to, electrophoretic, liquid crystal, plasma, OLED, and electrochromic. Of particular interest are displays (display layers) that are bi-stable or irreversible. Display layers may be further distinguished in accordance with their ability to reflect/absorb or pass/block light. An example of the latter that is of particular interest are electrophoretic displays comprising transparent electrodes where the charged particles may be positioned so that in one state they block light from passing, and in a second state they are moved out of the light path, and allow light to pass.
A light detection layer is typically sized appropriately to detect/measure light associated with the state of the display pixels and optionally, other areas such as that for detecting/measuring ambient light. A light detection layer (photoactive sensor) can be made of photovoltaic materials, light harvesting proteins, or other photoactive compounds. Preferred photovoltaic materials include organic photovoltaic materials (OPV) for ease of roll-to-roll manufacturing and optical properties (e.g. high transparency).
An exemplary embodiment of a light detection layer consists of a transparent electrode layer of ITO, an organic photovoltaic material based on for example Poly 3-hexylthiophene (P3HT) and an electrode layer (transparent or non-transparent) such as ITO, PEDOT:PSS, graphene, a metal conductor (e.g. Al), or a combination thereof. Of particular interest are organic photovoltaic devices that are near transparent or semitransparent (see e.g. US Pub. No. US20140084266 “Semi-transparent, transparent, stacked and top-illuminated organic photovoltaic devices,” and US20120186623 “Transparent Photovoltaic Cells,” and U.S. Pat. No. 5,176,758 “Translucent Photovoltaic Sheet Materials and Panels”). Bacteriorhodopsin (see, e.g., “Photoelectric response of polarization sensitive bacteriorhodopsin films,” Q. Li et al., Biosensors and Bioelectronics 19 (2004) 869-874, and included references) is a preferred light harvesting protein for the photoactive layer. In certain devices a light detection layer (e.g. photovoltaic photoactive sensor) also may serve a dual purpose and be used for message determination/verification and for energy harvesting.
In bistable liquid crystal display layers the pixel state corresponds to a change in the polarization of the light transmitting through the reflective display. This polarization change is in many configurations converted into a display reflectivity change by means of a linear polarization filter at the front (viewable) side of the display layer. Thus, as ambient light is typically randomly polarized, the maximum brightness of such a display, assuming an otherwise ideal display and polarizer, would be only ½ of that of a non-polarizing display. Furthermore, in the configuration illustrated in FIG. 1, a polarizing display layer 15 would also generate a smaller detected contrast ratio between bright and dark pixels in the light sensing layer 11. To first order and for an ideal polarizing liquid crystal display layer, the sensor (light sensing layer) would see 100% of the ambient light illuminating the sensor, for both bright and dark pixels, and 50% of the reflected light in a bright pixel (the other 50% is absorbed by the polarizer) versus 0% in a dark pixel, resulting in a maximum detected optical contrast ratio of 1.5:1 by the light sensing layer.
A display device may include a light source layer to improve the effectiveness and/or efficiency of light detection or measurement. The light source layer may be a thin film such as an OLED or transparent OLED (T-OLED) that generates light in the viewable area of the device. Alternatively the source of light in a light source layer may be outside the viewable area although the light is emitted in the viewable area. An exemplary embodiment of such a light source layer is an LED and a lightguide. Other techniques and processes are also know to one skilled in the art.
The light source layer is preferably optimized to emit light in wavelengths to which the light detection layer is most sensitive. For example, an LED that outputs light in a wavelength range of approximately 450-600 nm for a photovoltaic light detection layer consisting of P3HT. The light source layer and light detection layer may be optimized for, or intentionally limited to, wavelengths outside the visible light spectrum (e.g. to be machine but not human readable).
The display layer also may be optimized to absorb/reflect/transmit particular wavelengths of light in conjunction with the light source layer and/or light detection layer to enhance performance (detection, measurement, visibility, power etc.). The ink particles in an electrophoretic display (or the fluid in which they are suspended) for example, may be colored or otherwise optimized for that purpose. An example of an electrophoretic display with ink particles possessing photoluminescence is shown in FIG. 4.
Display layers, light detection layers and light source layers require electrodes typically configured on the top and the bottom of each layer. Each electrode layer may be configured with multiple electrodes. Depending on the display layer, light detection layer, or light source layer one or both of the electrode layers may be patterned. The pattern determines the shape and addressability of the display pixels, detection pixels and less often, light source pixels (typically the light source consists of two non-patterned electrodes effectively creating a single light pixel or layer).
Depending on the configuration of the device (and its composite structure), one or both of the electrode layers may be a transparent conductor such as ITO and other transparent conductive oxide, PEDOT:PSS and other conductive polymers, nanoparticle inks etc.). Typically, the electrodes in the light detection layer are configured so that they are in electrical contact with the photovoltaic material. Similarly, electrodes in light source layers consisting of a photoactive layer in the viewing area (e.g. OLED or T-OLED) are typically in electrical contact with the photoactive layer.
The electrodes in the certain display layers however, may be positioned on the outward facing surfaces of the display (e.g. on the outward facing surface of a barrier film). In some device configurations, an electrode layer can be used in more than one of the display, light detection and light source layers. For example, a single non-patterned electrode layer may be used when setting the display message, and separately used when activating a T-OLED light source layer.
In another example, a single patterned electrode layer is used when setting the states of the display pixels and separately when sensing/measuring light via the detection pixels. In this case, the patterned electrode layer determines the shape, position and addressability of both the display pixels and the detection pixels. And importantly it assures they are near-perfectly aligned so that the reflected light from, or transmissive light through, one display pixel corresponds to that detected/measured by the appropriate (paired) light detection pixel.
Electrode layers (transparent or opaque, patterned or non-patterned) can be configured in a variety of ways and placed in contact with other layers of a device. This allows for simpler devices and considerable flexibility in manufacturing, particularly where different processes are involved (e.g. chemical etching, vapor deposition, printing etc.). In one example, a transparent electrode layer is applied to the surface of a lightguide that is then placed in contact with the surface of a display layer (e.g. a barrier film or adhesive layer without an electrode layer of its own). Depending on the overall design, the common electrode layer could be patterned or non-patterned.
Alternatively, a photovoltaic material is deposited directly on a transparent electrode layer previously deposited on a lightguide. A separate display layer with an outward facing patterned electrode layer could then be combined to create a device consisting of a display layer, a light detection layer, and a light source layer—and using only three electrode layers. In a variant of the previous example, the photovoltaic material is deposited directly on the outward facing transparent electrode layer on the barrier film of display layer to which a light guide with a transparent electrode layer is placed in contact.
To simplify the overall device design and manufacturing processes the display, light detection and light source layers may be separately manufactured and then combined. A shared common patterned electrode manufactured as part of either the display layer or the light detection layer for example would avoid alignment problems common to roll-to-roll manufacturing processes. Alternatively, the component layers that make-up the display layer, light detection layer and light source layer may be fabricated advantageously in part or in whole, directly onto adjacent device layers. Devices may incorporate light absorbing or light reflecting materials to enhance the performance of the light detecting layer and the light source layer.
In an exemplary embodiment FIG. 3A, a display device 50 consists of display layer 51 and a light detection layer 52 where the light detection layer 52 is on the back side of the display layer 51, which front side 54 is facing the viewer and ambient light 53 impinges (if present). Further, the display layer 51 is of an electrophoretic micro-cup 57 configuration where each micro-cup 57 corresponds to a single pixel with charged and reflective particles of a single type suspended in a clear liquid 58 (shutter mode).
In a first state 61 the charged particles 55 are set along the viewable surface of the micro-cup 57 (through the application of a voltage across the front and appropriate back electrode of the display layer) thus blocking light from reaching the light detection layer. In a second state 63 the charged particles are moved to one side of the micro-cup 57 allowing light to pass through to the light detection layer 52. In the first state 61 the display pixel is reflective and from the viewer's perspective ‘bright’ compared to the second state 63. In the second state 63 the display pixel is largely transmissive as the ink particles 56 collect in a corner, and the light detection layer absorbs most of the light. From the viewer's perspective the display pixel appears comparatively ‘dark’. The shutter mode of the display layer can also be implemented with other display technologies than that of electrophoretics including that of LCD technology.
In a preferred embodiment, the color of the charged particle is chosen to maximize the reflectivity of visible light (e.g. ‘white’) and the composition of the light detection layer (top and bottom electrodes, photovoltaic materials) is chosen to absorb visible light. In configurations where the light detection layer is semitransparent, a light-absorbing material (which may be part of or separate from and behind the back electrode 61 of the light detection layer) may be incorporated to maximize the absorption (or reflectivity in combination with light absorbing ink particles). FIG. 3B shows the device 75 similar to the device 50 of 3 A but with the addition of a T-OLED 76 light source layer. For pixels with high aspect ratios, in which the vertical to lateral dimensional ratio of the pixels is high, it is further advantageous to directionalize the typically Lambertian distribution of the OLED emission to minimize any lateral crosstalk from adjacent pixel illumination consequently reducing state detection contrast. For instance, by employing external films to the OLED, adding microstructures or diffractive optical elements, the normal incident directionality can be enhanced to reduce such crosstalk.
Electronics may be integral, proximate or local to a device (or devices), distributed or remote and advantageously include a processor and circuits for receiving signals from the light detection layer, for transmitting signals to the display layer or light source layer. The communications or signaling may be by electrical connection or wireless.
The processor may be a microprocessor, and in some cases may be an embedded RFID or other purpose built (fit for use) processor. The processor may also include signal processing units for improved efficiency in processing received signals. Such a signal processing unit may be useful for more efficient determination of messages or patterns, for verifying messages, for determining states of a message, and for determining displayed, visual, and perceptible states. The processor may also be used for monitoring conditions, for example absolute timing or elapsed timing, or for receiving inputs from environmental sensors. In this way, the processor will provide conditional rules for making decisions as to what may be displayed, and possibly what level of perception is needed for the particular environment. Also, the electronics may include memory for storing messages, and processes for determining a subset of critical messages to store to save power and memory space. Electronics may also include various clocks, timers, sensors, antennas, transmitters, and receivers as needed. For particular applications the communication paths may also include encryption and decryption capability. The device may be powered locally by a battery or a capacitor, and may have energy harvesting systems such as RF, optical, thermal, mechanical, or solar. A device may further have of a switch, button, toggle or control for scrolling or switching between multiple messages on the same screen.
Methods and systems for verifying a displayed message with an intended message and for determining the message (or displayed patterns) and associated message state independent of an intended message, with electrical signals corresponding to electrical properties of display pixels are described in U.S. provisional patent application Ser. No. 14/927,098, entitled “Symbol Verification for an Intelligent Label Device.”
Those methods and systems may be used with electrical signals that correspond to the optical states of display pixels that correspond to reflected and/or transmitted light that corresponds to the state of display pixels; wavelengths of reflected and/or transmissive light that corresponds to the state of display pixels; or polarization of reflected and/or transmitted light that corresponds to the state of display pixels. Those methods and systems may further use measures of ambient light and/or light emitted by a light source layer (e.g. reference pixels, calibrated measurements). Those methods and systems may use electrical signals corresponding to the optical states of display pixels with and without ambient light, pre and post activation of a light source layer or different combinations thereof.
Importantly, and especially in the case of display layers with limited message stability, electrical signals corresponding to the optical states of display pixels are preferably stored along with the time or period the measurements are taken. As with electrical measurements of the electrical properties of display pixels, optical measurements can be initiated in response to events such as the setting message pixels, time, change in monitored/detected condition, absolute or elapsed time, external signal (e.g. electrical, RF, human and machine readable light etc.) etc. Similarly, the light source layer can be activated in response to a variety of ‘events’ and as appropriate precede or follow the setting of message pixels.
In one exemplary embodiment, an event first initiates a measurement of ambient light to determine if it is sufficient to effectively detect/measure the optical states of the message pixels. If the ambient light is insufficient (or uncertain), then the light source layer is activated and the optical measurements taken. Further, the output of the light source layer may be regulated in response to the level and composition of the ambient light. In some applications, the light source layer may be activated (e.g. flash) to alert users to a changed condition that warrants their attention (and in low light environments allows them to see an appropriate message). The detection signals from the light detection layer may be compensated for (e.g., through a calibration procedure) temperature (e.g. the conductivity of many organic polymers increase with higher temperature), supply voltage variation, detector dark current, average ambient light level, uneven light source distribution, pixel or segment size, manufacturing defects, etc. This allows for a more precise determination of the optical state of the pixel/segment (consequently allowing, for example, for detection of smaller pixels or more grey levels). In some preferred embodiments the calibration procedure may involve pixels (e.g. stable black and stable white reference pixels) outside of the active display area which may or may not be shielded from receiving any ambient light. In some embodiments a set of messages may be displayed in a series, randomly, pseudo randomly, in response to user control (e.g. by scrolling through them) etc. In such embodiments the displayed messages and their states may be individually verified or as a set. In the case of user control, the user inputs and timing may be recorded along with the verification data to encourage users to view/perceive the complete message set.
The results of message verification (e.g. of a displayed message to an intended message) can be used to trigger a separate viewable message independent of the first/primary message. The second/separate message for example could alert the user as to uncertainty regarding to the accuracy, visibility, perceptibility etc. of the primary message despite it being sensible. Preferably this “state of the message”, message would be simple and thus robust, reliable and serve to alert the viewer as to a fault with, or uncertainty in regards to, the primary message.
Meta systems receive data from devices/electronics/methods/systems (collectively “device data”) capable of verifying displayed messages (e.g. electrically or optically) and combine/use it with data from other sources to transact, analyze, monitor, etc. items, events and outcomes. Knowing that messages (and patterns) can be, or have been, verified/determined increases participation and proper usage, and confidence in the data, outcomes and meta systems. Meta systems typically involve data from multiple, often independent, parties. Some meta systems are typically centered on the item to which the device is attached and associated events or monitored conditions. An insurance or payment system for example may use device data received from the buyer (condition of an item), the seller (customer information) and shipper information (time of delivery). Other meta systems are typically centered on outcomes from the human (or machine) use of device data (as well as the device data itself). Meta systems for example, can analyze the impact of human (or machine) usage of device data of outcomes. Meta systems can help identify device or system failures vs. those of humans, whether they have been tampered and appropriately ‘localized’ (e.g. messages displayed in languages and date format appropriate to the location, custodian or user).
The outcomes (results) of a clinical trial for example, may depend on displayed messages being not only correct but also used correctly by healthcare professionals and participants. A meta system may therefore analyze outcomes of a clinical trial (e.g. marginal efficacy, adverse reaction etc.) with “action data” (human or machine actions in response to device data) as well as received device data.
The financial performance of a grocer for example may depend on messages as to the state of perishable foods (e.g. as ordered/acceptable, not as ordered/unacceptable or not as ordered, but acceptable at discount) being correct, perceptible etc. and appropriately used (e.g. accept, reject or request a discount). A meta system may therefore analyze outcomes such as sales, cost of goods sold, shrinkage or profit figures with action data (rejected shipments or discounts requested) as well as received device data. The meta system may further analyze outcomes involving suppliers (e.g. shipment condition over time, discounts issued etc.) in context of received device data.
In an exemplary display device 10, shown in FIG. 1, a detector layer or photoactive thin film sensor 11 consisting of a light sensitive layer 12 sandwiched between two transparent conductive layers, a front layer 13 respectively back layer 14. This photoactive thin film sensor is inserted on the front (i.e., readout side) of a reflective display 15. The light sensitive layer, or photoactive layer, may consist of a single compound or many layers, in order to provide an electrical signal (16 a, 16 b), e.g., a voltage differential, between the respective transparent conductive layers, when ambient light (18 a, 18 b) impinges onto the photoactive sensor system. In the configuration shown in FIG. 1, the electrical signal is dependent on not only on the ambient lighting (18 a, 18 b) conditions (intensity over the visible and/or invisible part of the electromagnetic spectrum), but also on the amount of light reflected back from the reflective underlying display pixel (19 a, 19 b). In effect, the ambient light (17 a, 17 b) passing through the front electrode 13 will act as an electrical bias on the detected electrical (16 a, 16 b) originating from the display pixel. This electrical signal (16 a, 16 b) can, in a similar way to that of the electrophoretic display described above, be used to verify the state of the display, preferably by first subtracting out the electrical bias signal. In the example illustrated in FIG. 1, the reflective display layer 15 has two pixels, one dark 20 a and one bright 20 b, with corresponding sensor pixels (21 a, 21 b). A proper separation 22 between the electrode layer 14 of the sensing pixels must be provided in at least one of the transparent layers (e.g. through gaps), i.e. 14 or 13, in order to measure the states of the desired pixels of the bistable display. The detector layer (photoactive film sensor) 11 can be fabricated with proper alignment directly onto the reflective display layer 15 or onto a supporting carrier film 23 for subsequent transfer onto the display. Many of the examples/illustrations described thus far presume that at least one of transparent electrodes (e.g. 33 in FIG. 2) that drive the display layer (e.g. the photoactive material 12 in FIG. 1 or 31 in FIG. 2) are on the surface of the substrate opposite that facing the display material (e.g. 38 in FIG. 2). It will be appreciated that there may also be a transparent electrode facing the display material. E.g. the carrier film 23 may have patterned ITO on both sides, each aligned to the other.
The photoactive layer in the above configurations can be made of photovoltaic materials, light harvesting proteins, or other photoactive compounds. Preferred photovoltaic materials include organic photovoltaic materials (OPV) for ease of roll-to-roll manufacturing and with optical properties of high transparency (for configurations shown in FIGS. 1 and 2) to minimize the impact of the display readability. Of particular interest are organic photovoltaic devices that are near transparent or semitransparent developed primarily for automotive and building window applications (see e.g. US Pub. No. US20140084266 “Semi-transparent, transparent, stacked and top-illuminated organic photovoltaic devices,” and US20120186623 “Transparent Photovoltaic Cells,” and U.S. Pat. No. 5,176,758 “Translucent Photovoltaic Sheet Materials and Panels”). Bacteriorhodopsin (see, e.g., “Photoelectric response of polarization sensitive bacteriorhodopsin films,” Q. Li et al., Biosensors and Bioelectronics 19 (2004) 869-874, and included references) is a preferred light harvesting protein for the photoactive layer.
In an exemplary display device 30, illustrated in FIG. 2, the photoactive layer 31 of the light detection layer 35, sandwiched between its front 32 and back 33 electrodes, is polarization sensitive and integrated with the polarizing display layer 34. The polarization sensitive photoactive sensor (light detection layer) 35 is inserted between the polarizer 36 and the front alignment layer 37 (typically glass or polymer film) of the bistable liquid crystal display layer 34. A typical reflective bistable liquid display layer also includes the liquid crystal layer itself 38, a back alignment layer 39 and a reflector 40, which also acts at the back electrode. However, depending on the configuration it may also include additional layers, such as a quarter-wave plate and an additional back polarizer (not shown for simplicity). Furthermore, as shown in FIG. 2, the pixelated back transparent conductor layer 33 for the sensor signal (41 a, 41 b), also acts as the pixelated front electrode of the display and is used for the display switching signal (42 a, 42 b), thus eliminating one transparent conductive layer in the (integrated sensor) display device 51 (or 30). In this configuration, with an ideal polarizing liquid crystal display and an in-plane-only polarization sensitive sensor, the sensor would see 50% (43 a, 43 b) of the ambient light (44 a, 44 b) illuminating the sensor (the other 50% is absorbed by the polarizer), for both a dark (45 a) and a bright pixel (45 b), and 0% of the reflected light in a dark pixel (46 a) due to liquid crystal induced orthogonal polarization versus 50% in a bright pixel (46 b), resulting in a maximum optical sensing contrast ratio of 2:1. The polarization sensitive film 31 maybe made from incorporation of nanowire or nano-tube technology, or by preferentially photochemically bleaching of bacteriorhodopsin (see, e.g., “Photoelectric response of polarization sensitive bacteriorhodopsin films,” Q. Li et al., Biosensors and Bioelectronics 19 (2004) 869-874).
In this exemplary display 50, illustrated in FIG. 3A, the light detection layer 52 is located behind a bistable electrophoretic display layer 51. The electrophoretic display 51 illustrated contains visibly white ink particles (55, 56) in a clear fluid 58 contained in a segmented microcup 57 configuration. In a first state 61, corresponding to a bright segment from the viewing side 54, the white ink particles 55 are distributed at the front surface of the microcup 57 after applying an appropriate switching voltage to the electrodes 59 and front transparent conductor 65 of the display layer 51. In this state 61, the ambient light is reflected by the white ink particles 55 (creating a bright viewable segment) and largely blocked from going through the segment cup 57 and reaching the light detection layer 52. In the second state 63, corresponding to a viewable dark segment, the white ink particles 56 are displaced to a smaller lateral region at the side and toward the back of the segment cup 57 after applying an appropriate switching voltage to a smaller area-sized electrode 59 in the back and the front transparent conductor 65 of the display layer 51. In this mode most of the ambient light passes through the microcup cell 57 and further onto the light detection layer 52. A visible light absorbing conductor 61 is preferred on the back of the light detection layer 52, in order to yield a higher contrast of the displayed message. In this configuration the light detection layer 52 is exposed to the complementary light level of the segment state as compared to that viewable by the observer of the display.
In the exemplary display device, illustrated in FIG. 3B, a device 75 similar to the device 50 of FIG. 3A is shown. An integral light source layer 76 (e.g., as illustrated here: T-OLED) advantageously with normal incidence emission directionality, is added to the front face of the device configuration. The integral light source layer 76 allows for increased detection levels at the light detection layer and ability to discriminate between the states of the display. This exemplary configuration is preferred when the state detection takes place under low ambient lighting conditions or in a dark environment.
In the exemplary display device 125, illustrated in FIG. 4, a display is shown similar to devices of FIG. 3A/B, previously described, so only the differences will be highlighted. In device 125, an electrophoretic display layer 127 comprising a two ink particle system with the light source layer 129 emitting a shorter wavelength (e.g., UV illumination) and first ink particles 131 (e.g. visibly white) possessing a photoluminescent property in which the first ink particles 131 emit a longer wavelength(s) (e.g. in the visible spectrum) when subjected to the illumination of the light source layer through phosphorescence or fluorescence. This longer wavelength can further be used to illuminate the display layer 127 (front or back) and enhance the detection by the light detection layer 128. When illuminated from the front and detected from the back of the display as shown in FIG. 4, it may be advantageous to also select the second ink particles 133 (e.g., visibly black) to also transmit the shorter wavelength (e.g., UV) of the light source layer 129 such that the illumination can pass through the second ink particle layer 133 in order to reach the first ink particle 131 layer further allowing for the longer wavelength radiated light to be detected.
In the exemplary device, illustrated in FIG. 5, a display device 175 is shown similar to the devices of FIGS. 3AB and 4, previously described, so only the differences will be highlighted. In display device 175, both the light source layer 176 and the light detection layer 177 are situated in front of the display 179 (here illustrated as a microencapsulated electrophoretic display). This configuration allows for optical state detection, with or without the presence of ambient light, from the same side as the observer, and is particularly favorable for reflective displays that do not have a complementary optical state detection capability from the back side of the display. The exemplary light source layer 176 illustrated consists of an LED 181 edge-lit light guide plate 182 (see e.g. Planetech International or FLEx Lighting), which redirects and distributes the light from the LED towards the display layer 179. This particular configuration also allows the light source layer 176 to aid the observer in viewing the display under dark ambient lighting conditions. However, it should be noted that this front lit configuration also induces undesirable bias light (independent of the display state) onto the light detection layer 177. Furthermore, both the light source layer 176 and the light detection layer 177 must provide significant optical transmission as to not significantly deteriorate the brightness and contrast of the observed display. As in other configurations, the segmented (or patterned) transparent conductor 184 can favorably both be used to switch the state of the display segment, as well as, to determine the state of the corresponding segment by the light detection layer.
In the exemplary device, illustrated in FIG. 6, a display device 225 is shown similar to the devices of FIGS. 3A/B, 4 and 5, previously described, so only the differences will be highlighted. Device 225 has reverse stack configuration as compared to that in FIG. 5, and is shown with a two particle microencapsulated electrophoretic display layer 227. By using complementary optical state detection from the back side of the display, the display performance, including brightness and contrast, from the viewer side is uncompromised. Additionally, the common segmented transparent conductor is on the back side of the display further improving the displayed message, by reducing any potential visual ghosting effects from the (non-ideal) transmission of the conductor.
FIGS. 7A and 7B show two configurations for an emissive display device 250 with a photosensitive detector 251. Detector 251 has the same general structures as already discussed with reference to FIGS. 3-6, so will not be discussed in detail in this section. Detector 251 and display layer 255 both have their own top and bottom substrates, 252 a/b and 256 a/b respectively, but it is also possible that they share a substrate or are even integrated without a substrate separating the two. In FIG. 7A, configuration 250 shows the detector layer 251 configured in front of the display layer 255. As will be understood, the top of device 250 is the front side that is positioned toward a viewer, and the bottom of the device 250 is the back side that is positioned away from a viewer. In FIG. 7B, configuration 260 uses the fact that emissive displays in general emit light in both directions. By placing the detector 251 under the display 255 the back emission is detected. The amount of back emission can be tuned by the reflectivity of the back electrode of the emissive display. The additional advantage of this configuration is that the sensor receives less ambient light. The abbreviations in FIGS. 7A, 7B and 8 are defined as follows: SUB (substrate); DTE (Display Top Electrode); EM (Emissive Layer); PE (Pixel Electrodes); STE (Sensor Top Electrode); PS (Photo Sensitive Layer); CF (Color Filter); SU (Shutter); BL (Backlight); and SBE (Sensor Bottom Electrode).
FIG. 8 shows an exemplary embodiment of a display device 275 with a backlight 276, a shutter 277 (for example an LC layer with polarizers) and a front detector 279. The middle substrate 281 can again be shared, or the detector 279 and the display 283 can even integrated without a separating substrate and the color filter 285 is optional.
The exemplary embodiments of display devices 250, 260, and 275 require power in order to show the image. An intelligent label that is directly connected to a large power source or to the power grid could operate continuously or for extended periods of time. This could be possible in for example a store setting where the intelligent label is showing the price of an item. The intelligent label can be continuously powered in that case and can show the information continuously. The exemplary embodiments make it possible to also continuously verify if the information is displayed correctly or verify this whenever needed.
An intelligent label may have an actuator that activates the display temporarily from time to time responsive to an activation signal, for example a signal from an environmental sensor. The sensor could be a proximity sensor, an (IR) movement sensor, a push button, a touch interface, a bend sensor (strain gage), a microphone or an accelerometer, etc. The message actuator ensures that the display is mostly off in order to conserve power. The display could be activated for a certain amount of time or until the sensor does not detect movement, touch, finger push or bending (movement) or sound for a certain amount of time. Detecting the state of the display now becomes more energy efficient, as the display is only on for certain short periods of time. Detecting the state just at the start of an activation period may be sufficient, instead of detecting the state of the display at various moments in time for a permanent (bistable) display as used in selected other embodiments.
A block diagram 300 of the intelligent label 305 with the message actuator 306 is show in FIG. 9. The different elements have the same function as outlined in co-pending U.S. patent application Ser. No. 14/586,672, filed Dec. 30, 2014 and entitled “Intelligent Label Device and Method,” which is incorporated herein by reference as if set forth in its entirety. The message actuator 306 communicates with the state detector (sensor) 307 as described above that sends the activation signal to the electronics of the intelligent label to activate the display (i.e. the message indicators 308 and 309) and shows the message and also sends a deactivation signal based upon a timer or a sensor deactivation signal, or a combination of these two.
Compensating for ambient light with an emissive display is possible by inserting short periods of time where the display is not emitting light. During that time the sensor only senses the ambient light. That measurement can be used to correct for any bias, such as high ambient light intensity or spatially or temporal changes in ambient light intensity over the display. For the OLED or Quantum Dot (QD) displays the emission can be turned off by powering off the pixels. In a backlit LC display this can either be done by changing all pixels to the black state or by turning off the backlight.
Typically, emissive displays, such as OLED, LC (with integrated light), or QD can switch very fast. For example, OLED or QD can switch between on and off within microseconds, while modern LC can switch within 1 millisecond. A scheme can thus preferably be implemented for each image frame update (of for example 20 ms (50 Hz)) wherein a small portion (e.g., a few milliseconds) would be reserved for ambient light sensing. As this can be done very fast, the viewer will not see any flickering. Alternatively, ambient light sensing could be done at the start and/or at the end of displaying the information in case the display is not always on. Further, it is also possible to insert the off-period per row, column, pixel, etc instead of for the whole display at the same time. This could have the advantage of being more pleasing to the viewer.
It is desirable that an emissive display is almost always visible, even in dark environments as it does not rely on an external light source. Also, the state detection of the display could become more easy for a display that only show the information when activated. Further, due to the fast switching capabilities of most emissive displays, efficient compensation of the ambient light is possible.
Integrated Optical Detection of Content on Displays
Optical touch solutions. Touch systems are interesting to use for inspiration as they are used to detect an object touching (or being in proximity) to the display. Especially in-cell optical touch systems are interesting as they are using light to detect an object. The following optical in-cell touch solutions currently exist.
Light-sensing in-cell touch. The basic principle for sensing of light within the display 325 in shown in FIG. 10. Typically, a backlight 327 is used behind the display 325, usually an LCD, where an object, e.g. a finger 329, on the display 325 reflects the light from the backlight 327 back to a detector 331 that is integrated on the backplane 333 of the LCD. One of the major difficulties with this technology is sensitivity under all lighting conditions. Therefore high intensity IR light is added to the backlight 327 and an IR sensitive sensor 331 is used.
In FIG. 11, a structure 350 using a photo TFT 351 (thin film transistor) and a readout TFT 352 that is used to read-out the photo sensor is shown. The photo TFT 351 can receive reflected light through the opening 355 in the black matrix 357 laterally offset from the color filter 359, while the read-out TFT 352 is under the black matrix 357. The photo TFT 351 typically has a light blocking layer as a first (bottom) layer in order to avoid direct illumination from the back light. As the photo diodes are typically sensitive to temperature as well, the accuracy of the light sensing can be increased by adding a 2nd diode that only measures the effect of the local temperature (i.e. has a bottom and top light blocking layer) and is subtracted from the photo diode signal.
In FIG. 12 a backplane circuit 400 for an active-matrix LCD with integrated light sensors is shown. One light sensor is implemented for every 4 pixels, although it is possible to implement more or less light sensors as well. The light sensing circuit is a simple 2 TFT circuit as shown in FIG. 11. The sensing circuit shares a number of line with the pixel circuits to simplify the external wiring. The circuits works by first putting a bias on the capacitor Cst2 that leaks away through the photo TFT depending on the light intensity. By reading the remaining bias on the storage capacitor after a certain amount of time (e.g. 20 ms) the average light intensity on the photo TFT can be calculated.
In FIG. 13A a pixel circuit 425 for an AMOLED is shown with integrated scanner function. The photodiode is made from a p-i-m amorphous silicon diode. FIG. 13B illustrates a timing diagram 450 for the circuit of FIG. 13A.
In FIG. 14, the relationship 475 between the drain-source current through the photo TFT as a function of the light intensity is shown. It is clear that an a-Si photo diode can be used very effectively for light sensing.
OLED compensation circuits using optical sensors. In FIG. 15, an OLED compensation circuit 500 based on optical feedback is shown. The photo TFT is an a-Si NIP diode integrated on the backplane. The photo TFT detects the light coming from the OLED. The drain-source current from the photo TFT determines the amount of time the OLED is on during a frame. This compensates for degradation of the OLED by making the on-time of a degraded OLED longer such that the integrated light output over one frame is equal to that of a fresh OLED.
In one embodiment, the general implementation consists of integration of or adding a light sensitive element to the display. For an active matrix display the optimal solution is to integrate the light sensitive element directly in the active matrix as already proposed for in-cell touch and OLED compensation. For a segmented or passive matrix display the light sensitive element can be incorporated into one of the substrates or can be created on a separate substrate and adhered to the bottom or the top of the display as already proposed for the light sensitive layer in previous embodiments.
In the various embodiments below a light blocking layer is proposed to shield contribution from the ambient light falling onto the photo detector. This light shielding layer can also be used in various embodiments as previously described in order to improve the signal to noise ratio.
Integrated light sensitive element in a back lit reflective display. In this embodiment 525 illustrated in FIG. 16, a reflective display 526, such as an electrophoretic E Ink display, is used in combination with a backlight 527 as a light source and an integrated optical sensor 528, such as a photo diode or a photo transistor as the detector. The optical display (from the back side) will scatter the light back onto the light sensor, with a light level indicative of the optical state of the display (pixel). In case of an E Ink electrophoretic display, the sensor 528 will sense the inverse image as it is sensing on the backside. When the backside of the display is black only a fraction of the light impinges on the sensor as compared to a white state. Intermediary grey states can also be detected.
Especially for an E Ink display this is preferable as the E Ink medium needs a transistor backplane for matrix displays. The optical sensor 528 can then be implemented as a light sensitive transistor in the same technology as already used for the matrix backplane. The light shield 531 under the sensor 528 can easily be implemented by using one of the metal layers underneath the sensor 528. Of course it is possible to use the sensor 528 without a light shield 531, but the optical contrast will then be much lower. The backlight 527 can also only emit non-visible light, such as IR or UV, in order to avoid light leakage through the reflective display impacting the viewer. The sensor 528 can be tuned to be sensitive to the particular wavelength of the backlight. In this embodiment vertical separation (e.g. a spacer layer) of the optical sensor 528 and the reflective display 526 is desirable in case larger pixel areas are employed.
Separate light sensitive element in a back lit reflective display. It is also possible to add the light sensitive element as a separate layer to the display, as shown in FIG. 17. This could be useful in case a simple display structure, such as a few segments, is used or when a separate add-on is more economical. The bottom display substrate and electrode structure must be transparent enough to be able to sense the switching state of the display medium through these layers. This can be done by using ITO or other transparent metals for the pixel electrode.
In display 600 of FIG. 17, a backlight 601 is used in combination with a light sensor sheet 602. Depending on the required pixel resolution the light sensor sheet 602 can be made with light sensitive transistors or diodes build by photolithography. In cases where the resolution is lower it is also possible to mount discrete light sensors to a flex foil, as long as the flex foil has enough transparency for the backlight. This embodiment is similar to the embodiment shown in FIG. 6, but is now using an optical sensor with a light shielding element instead of a photosensitive layer.
In the display 625 of the embodiment shown in FIG. 17, a separate sheet 626 with light sources and light sensors in a side-by-side configuration is integrated. This is typically a low resolution solution build with discrete components (e.g. LEDs and photo detectors) on a flex foil, although it is also possible to build such a layer with high resolution OLED with integrated photo diodes or transistors. As in this embodiment an array of light sources and detectors is used, it is possible to switch light sources and detectors sequentially or in groups in order to get the best possible optical contrast for the display state verification.
In display 650 of FIG. 17, a separate sheet 651 only contains the light sources in a side-by-side configuration, while a photosensitive layer 652 is positioned behind the display and the light source layer. By switching one light source on at-a-time the detector will detect the switching state of the illuminated part of the display. This works well for low resolution segmented displays or, in case the light sources are made in a high resolution technology, like a matrix OLED array, this could even be used for high resolution matrix displays. Of course the photosensitive layer could contain multiple discrete sensors for a faster response time, like in display 626 or be processed in a grid with row and column electrodes.
Emissive display (e.g. OLED) with light sensitive element. In FIG. 18, an emissive display 700 embodiment with an integrated optical sensor is shown. The emissive layer emits light in all directions. The light that is emitted down is sensed by the optical sensor. The optical sensor can be integrated into the active matrix using the same layers and technology. The optional light shield layer shields the ambient light from the sensor in order to reduce bias. Instead of an absorbing layer it is also possible to make it a reflective layer as that increases the amount of light falling on the optical sensor even further, but it will also decrease the display optical performance for the viewer. Advantageously, the shield layer can be reflective on the back side and absorbing on the front side In another embodiment the optical sensor is positioned just below the light shielding layer and above the emissive layer, but the disadvantage of that is that the sensor now needs to be processed separately and cannot be made at the same time as the electrodes and transistors on the bottom substrate.
In FIG. 19 a similar structure 725 is shown, but now with the light sensor implemented in a separate sheet. This could be beneficial for simple segmented emissive displays or when it is more economical to separate the display and sensing functions. In this case it is important to have enough light emitting towards the back of the display in order to sense the state of the display. This can be achieved by making the bottom display electrode semitransparent. This embodiment is similar to the embodiment shown in FIG. 7A, but is now using an optical sensor with a light shielding element instead of a photosensitive layer.
It is also possible to position the separate substrate with the optical sensor on top of the display, that is, with the optical detector on the front side of the substrate and in front of the display layer. In that case the optical sensor could have an additional ambient light blocking layer. The disadvantage of that configuration is the decreased optical performance of the display and the requirement for optical transparency on the sensor layers and substrate. This configuration would be similar to the embodiment shown in FIG. 8, but is now using an optical sensor with a light shielding element instead of a photosensitive layer.
Integrated light sensitive element in shutter display. In FIG. 20, a shutter display 750 with an integrated optical sensor is shown. A shutter display has various degrees of transparency depending on the switching state of the material. For example, in case liquid crystal (LC) is used, the LC can be switched between a semitransparent state and a dark state by sandwiching the LC material between crossed polarizers. In case the display has a backlight it is advantageous to use a light shield layer just below the light sensor to reduce signal bias induced by the backlight. By using a front light, the light sensor can detect the state of the pixels even without ambient light. Further, by using non-visible (IR) light in the front light the optical performance in the visible wavelength range is largely unaffected, while the signal level for the optical detector could be further increased. In case the shutter display is a reflective display (with a reflective bottom electrode), a backlight is not functional, but the front light could provide additional visibility for the user and the sensor when the ambient light is poor. Again, it is also possible to add a separate detector sheet behind or in front of the display and in case the resolution is low it is also possible to add discrete light sensors on a flex foil to the display. Accordingly, a simple way to integrate light sensing is provided by using the active-matrix transistors to sense the state of the display.
Optical Shutter for Blocking Ambient Light During State Detection
In general, in the following embodiments an optical shutter is added to the display, such that the photo sensitive layer only receives the reflection, transmission, or emission from one pixel at a time. The advantage is that this allows the photo sensitive layer to be unpatterned (i.e. not have any pixels) which makes it much easier to manufacture. As the shutter can be a simple LC display, the shutter and the display can be made with the same manufacturing infrastructure which makes it easy to manufacture with matching pixel size and shape. LC displays are now extremely cheap, thus adding only marginally to the cost of the display system. Also, it is possible to make the shutter normally transparent (i.e. normally white) in order to make the transparent state the state without any power to the shutter.
The photo sensitive layer is preferably made by a solar cell type of manufacturing infrastructure, having much larger feature sizes compared to displays. By adding the shutter, the photo sensitive layer does not need to be pixelated anymore, something that is very compatible with the general structure of solar cells. Of course it is also possible to use other materials for the photo sensitive layer, such as photosensitive transistor or diode structures, or even use discrete photo sensitive components mounted on a flex board, as also previously described.
Reflective display with shutter and photo sensitive layer. In FIG. 21, a reflective display device 800, with an exemplary electrophoretic display layer 801, is shown with a photo sensitive layer 802 in front. A shutter 803 is positioned in front of the photo sensitive layer 802. The shutter 803 has a pixelation that is such that it can pass or block light per pixel of the display. Depending on the type of display (e.g. high resolution matrix or segments) the pixelation of the shutter 803 can be identical to the display or it can be different (larger or smaller than one pixel), but still allowing the passing or blocking of the light per (part of a) display pixel.
The photosensitive layer 802 is not pixelated and only registers the amount of light that is passing through its light sensitive layer. By switching the shutter from pixel to pixel, the state of each pixel can be registered.
The front light 804 and color filter 805 are optional. Substrates can be shared or some of the components could even by monolithically integrated on top of each other.
Of course the user looking at the display will see the shutter 803 blocking part of the image depending on the speed of the shutter and the way the shutter 803 is driven. This can be addressed by operating the shutter 803 at a high speed, for example 50 Hz or higher. When all pixels are scanned once every 20 ms, the user cannot see the shutter 803 operating the individual pixels anymore; it will only see that the average brightness is lower. In order to get a good measurement of the switching state of the pixels, the pixels can be opened by the shutter multiple times, for example 50 times. This would result in a total measurement time of 1 second, where each pixel is measured 50 times for short periods of time. It is also possible to use more complex shutter addressing schemes, such as blocking only one pixel at a time in order to measure the loss of light on the sensor per pixel that is blocked. This has the advantage that the user will still see most of the image. When this way of measuring the state is performed at a high speed as described above, the user will hardly notice the measurement. Even more complex measurement schemes can be used, where (orthogonal) blocks of pixels are blocked at a time, such that the sum of the blocks of pixels that are measured give the information about all the individual pixels. Again this can be done at high speed by scanning multiple times.
An alternative embodiment 810 is shown in FIG. 22, where now both the shutter 813 and the photo sensitive layer 812 are pixelated, such that the combination of the two allows a per display pixel measurement of the switching state. Any trade-off is possible between the two layers in order to find the optimal solution from a manufacturability and cost standpoint. This same embodiment can be used for all other embodiments below, where this is not specifically added as a separate embodiment.
In FIG. 23 an alternative embodiment 820 is shown where the shutter 823 is positioned in-between the back light 826 and the photo sensitive layer 822. The photo sensitive layer 822 now senses the switching state of the backside of the display. For some reflective displays, such as electrophoretic E Ink 821, this results in a detection of the inverse state as compared to the state at the viewing side. This embodiment can also be well used for shutter like display effects, such as LC, instead of reflective E Ink. In that case the front light is omitted, but the rest of the stack is the same. Again, it is also possible to pixelate both the photo sensor and the shutter, such that the combined resolution allows for per display pixel sensing.
In FIG. 24 an embodiment 830 using a shutter 833 is shown for a reflective display that is switched between a reflective state and a transparent state, such as a Cholesteric Texture Liquid Crystal (CTLC) display layer 835. The shutter again selects the pixel to be measured. When the display pixel is in its reflective state the photo sensor will not detect light, while it does detect light when it is in its transparent state. The reflectivity curve 839 for the CTLC display 838 is also illustrated.
In FIG. 25 the shutter embodiment is shown for an emissive display 840. Compared to the embodiments above the emissive display is not bi-stable, so it only emits light when it is powered. As the emissive display typically emits light in both directions, the light emitted towards the back is used to detect the state of the display. The amount of light that is emitted towards the back can be tuned by optimizing the layer thickness of the back electrodes of the display layer. There is a back absorber or reflector 847 added at the far back layer of the stack. Typically, this will be an absorber, as reflection of the light can, on the one hand, create unwanted interference effects, but reflection, can on the other hand, increase the light intensity impinging on the photosensitive layer allowing for a stronger detection signal.
In FIG. 26 a simplified embodiment 850 is shown where the shutter function 853 has been integrated into the emissive display layer. When the emissive layer is showing the image to the viewer, it can modulate each pixel at a high speed, such that the photo sensitive layer can detect the change in light and thereby can detect the correct switching state of the pixel. This can be done with the same methods described for drive schemes of the shutter above.
In FIG. 27 the embodiment 860 of the emissive display with the shutter 863 and photo sensitive layer 862 in front of the display is shown. The advantage of this embodiment is that the emission of the display is unidirectional towards the viewer. The disadvantage is that more layers are now between the display and the viewer including the shutter that needs to be operated. Of course the integrated shutter function into the emissive layer can be used here as well, as shown in device 850.
In FIG. 28 an embodiment 870 is shown where a shutter 873 display effect is used, both to display the image and to function as the shutter for the photo sensitive layer 872. By using the high-speed per pixel switching as described above the user will not see the per pixel sensing while the image is displayed. This is very similar to the embodiment proposed in FIG. 26, but now using a shutter display effect with a backlight. The sensing is now done as follows: while the (static) image is displayed the shutter display effect switches every pixel individually to the inverse state and back again to the original state at high speed (50 Hz or higher). By doing this multiple times (50 times for example) the photo sensitive layer registers the state of the pixel by a change in the light falling on the sensor. Other drive schemes, as discussed above are also possible. This way the user still sees the (static) image, while the sensor registers what is displayed. Of course the sensor will also be exposed to ambient light. Therefore, using a specific wavelength, such as IR, in the backlight with the sensitivity of the photosensitive layer tuned for the same wavelength, would minimize the effect of ambient light. Further advantageously, the backlight could be modulated (or strobed) from two light sources, e.g. one emitting in the visible wavelength range for viewing the emissive display and one emitting at a wavelength range outside of the visible range (e.g. in the IR or UV) for detection purposes with a corresponding wavelength-tuned detector.
In FIG. 29 a similar embodiment 880 is shown, but now using a reflective shutter 883 type display effect. In this case the photo sensor 882 will always be subjected to the bias light from the front light while detecting the pixel state at high speed. This is possible by the polarization sensitive sensors as previously discussed with the front side polarizer of the display layer placed in front of the detection layer. Accordingly, an unpatterned or coarsely patterned photo sensor can be used in combination with a low-cost off-the-shelf shutter.
Addressing Schemes and Electrode Structures for Verification of Displays
Display pixel state verification by a detector generally requires a detector that has at least the same resolution as the pixels of the display itself. Especially for high resolution displays this would require an expensive optical detection system. Further, large area optical sensors, such as solar cells, are manufactured with different (low resolution) infrastructure than displays. The applicability of an optical sensor it is therefore highest when the resolution requirements on the sensor are low.
In one embodiment a lower resolution optical sensor in combination with a consecutive update of the display in matching orthogonal blocks can be employed to determine the optical state of the display pixels. Alternatively, in another embodiment, a scanning front or backlight can be used. These systems and methods can be applied to not only bi-stable displays, such as electrophoretic and CTLC displays, but also to non bi-stable displays, such as LCD, OLED, QD or micro LED. It is applicable to segmented displays, passive matrix displays and active matrix displays. In all cases a differential signal is recorded by the sensor, meaning that the pixels are switched to a reference state and the final state, where the difference is recorded for verification of the state of the pixel. The sensor can be a solar cell, a (integrated) transistor sensor, a discrete grid of optical sensors, a capacitive sensor or any other kind of sensor that can record the (change of the) switching state of a pixel or a group of pixels.
Consecutive display addressing. In FIG. 30 an embodiment 900 is shown where the display 901 is updated directionally. The new content is written to the display 901 from left to right, i.e. pixel column by pixel column in this case. This makes it possible to use a simplified, low-resolution optical sensor 902 that only has electrode stripes from left to right instead of a matrix that matches the pixel structure. Every time a new pixel column is updated, the sensor detects the change in optical state per pixel in the column, as the rest of the pixels in the rows are static.
In general, the display 901 does not have to be updated from left to right or top to bottom as long as every group of pixels that is updated at the same time only triggers a response on one of the optical detector segments. Therefore, this same approach can also be used for segmented displays or displays with other shapes. An example 910 is shown in FIG. 31. Note that in FIG. 31, the figure on left can also be achieved with only three sensor stripes as illustrated in the figure on the right.
An example of an alternative 920 approach would be to have an optical sensor array 922 consisting of rectangular pixels that are large enough to overlap with 5×5 display pixels 921, as shown in FIG. 32. By updating the display such that in 25 steps every pixel in the 5×5 blocks is updated sequentially, the sensor pixels detect only the change per pixel resulting in a verification of the display state.
In the case of a bi-stable display, such as an electrophoretic or CTLC display, the display is always showing information, even when it is not powered. It is therefore best if the pixels are first switched to a known reference state (e.g. black) followed by switching them to the new state. That way the detector can detect the change in optical signal when the pixels are refreshed. Even when the image is static and does not need to change the information that is displayed, the verification action should trigger this update in order to correctly verify the state of the pixels by detecting a difference per pixel. In the case of a non bi-stable display, such as an LCD, the display is only showing information when it is powered and scanned. LCDs can either be segmented, passive matrix, or active matrix.
Segmented LCDs are direct-driven with each segment directly coupled to an output of a driver chip. Such displays can be driven in the same way as indicated in FIG. 31, where each group of segments is put in its on-state (or in its off-state) sequentially. It is also possible to use another defined grey state instead of the off or on state. When the scanning is done fast enough (e.g. >=50 Hz) the viewer just sees the image on the display, but the sensor can still sense the optical changes of the individual groups of segments.
Passive matrix LCDs are usually driven by scanning in a certain direction, for example from left to right. During the activation of a certain column of pixels, the pixels are put into a switching state that generates the right grey level for the frame time. After that all other columns are selected and addressed. By scanning fast enough (e.g. >=50 Hz) the viewer does not see the scanning per column anymore but just the complete image. By combining the passive matrix addressing scheme with a simplified optical sensor, as shown in FIGS. 30 and 32, the sensor will detect the switching of every individual pixel during the addressing. Through this scheme the optical state of every pixel can be verified.
Active matrix LCDs use a transistor circuit per pixel in order to generate a substantially constant switching state (i.e. light output) per pixel during a frame time. The pixels are refreshed a row-at-a-time at high speed in order to show moving or static images. In order to use the simplified detector as shown in FIG. 30 and FIG. 32, it is advantageous to insert a short pixel-off interval (or alternatively a reference pixel switching state) per row during every scan to detect the difference between the off-state and the new state for all the pixels by the simplified detector. This method requires a fast LC switching effect and detector.
Scanning front or back light. In FIG. 33, example display 950 cross sections are shown with either a back light 951 or a front light 952. In these configurations it is possible to combine the resolution of the front light 951 or back light 952 with that of the optical sensor 953 such that the resolution requirement of the sensor is reduced.
In FIG. 34 an example 975 is shown where the front or back light 976 is scanning from left to right over time, resulting in a simplified structure for the optical sensor 977. The scanning frequency can be so high that the viewer cannot perceive the scanning of the front of back light 976, while the optical sensor 977 can now detect the (change of) light per area of the display 978 that is lit by the front of back light. Important to note is that the combination of the front or back light 976 resolution and the optical detector 977 resolution must be equal to the pixel resolution of the display 978 in order to verify the pixels individually.
Again several configurations are possible that can be used for segmented, as well as, matrix displays. It is also possible to create back or front lights that scan in a different pattern, such as a block pattern instead of a stripe pattern. The scan pattern of the front or back light can be different than just a walking 1 (i.e. only one of the front or back light “pixels” on). It is also possible to have a walking 0 (i.e. all but one of the front or backlight “pixels” is on) or even a more complex pattern where also dimming between on and off can be used. It is advantageous to have at least a state where the complete back or front light is either on and off in order to detect the complete signal and the ambient only signal, respectively. These signals in combination with the scanning signals can then be used to create the per pixel verification of the state of the display.
It is also possible to combine a consecutive update of the display with a scanning front or backlight in order to simplify the optical sensor. An example 980 is shown in FIG. 35, where the combination of the scanning front or back light 981 with the consecutive update of the display 982 results in the possibility to use an unpatterned optical detector 983. In order to sense the optical change of every pixel individually, the front or back light 981 has to do at least one complete scan per row of pixels that is addressed. As scanning front or back lights can typically scan at a high frequency (>=50 Hz) this is generally possible.
Emissive displays. In the case of an emissive display device 990, essentially the front or backlight and the display are integrated into one. By using a fast scanning update scheme, as discussed with reference to FIG. 26, it is possible to simplify the optical sensor 991 electrode structure, as shown in FIG. 36. The emissive display 992 is showing the image by emitting light from the pixels. Typically, this can be achieved by OLED, QD, or micro LED type of displays. There are generally 3 types of emissive displays: segmented, passive-matrix and active-matrix. Segmented emissive displays are direct-driven with each segment directly coupled to an output of a driver chip. These can be driven in the same way as indicated in FIG. 31, where each group of segments is put in its on-state (or in its off-state) sequentially. It is also possible to use another defined grey state instead of the off or on state. When the scanning is done fast enough (e.g. >=50 Hz) the viewing cannot see it, but the sensor can still sense the difference in light output per pixel.
Passive matrix emissive displays are usually driven by scanning in a certain direction, for example from left to right. During the activation of a certain column of pixels, the pixels are flashed to a high intensity level. During the time all other columns are selected, the column does not emit light. By scanning fast enough (e.g. >=50 Hz) the viewer does not see the flashing anymore but just the complete image. By combining the passive matrix emissive addressing scheme with a simplified optical sensor, as shown in FIG. 36, the sensor will detect the flashing of every individual pixel during the addressing. Through this method the optical state of every pixel can be verified.
Active matrix emissive displays use a transistor circuit per pixel in order to generate a substantially constant light output per pixel during a frame time. The pixels are refreshed row-at-a-time at high speed in order to show moving or static images. In order to use the simplified detector as shown in FIG. 36, it is advantageous to insert a short pixel-off interval (or generally a reference state interval) per row during every scan to detect the difference between the off-state and the new state for all the pixels by the simplified detector.
It is also possible to use other scan methods for the active matrix emissive display, such as putting the pixels to the reference state individually while scanning the display, for example by putting one pixel to the reference state per frame. Accordingly, an unpatterned optical detector can be used to detect the optical state of each pixel by detecting the difference between the light output in the reference state and the actual state of the pixel. Verifying the state of all pixels takes longer in that case. Other patterns can also be used. Accordingly, by using smart addressing schemes, the sensor can be simplified resulting in a total system that is easier to manufacture.
Compensation for Ambient Light in Front or Backlit Systems
An issue may arise due to the dependence of the display state detection signal on the local or temporal fluctuations of the ambient light. This can lead to unreliable detection and verification of the pixel state.
In one example embodiment 1000 shown in FIG. 37, two consecutive measurements 1001, 1002 are made with a reflective display layer 1006 with a front light 1005. The first measurement 1001 is done with the lighting 1005 off, while the second measurement 1002 is done with the lighting 1005 on. The difference between the two signals corresponds to the ambient light contribution, which can thus be compensated for in the state detection signal (by subtracting a bias). In FIG. 37 the width of the arrow pointing towards the pixels represents the local amount of ambient light falling on the part of the display. Without these two consecutive measurements, the possible spatial fluctuations in ambient light intensity can easily lead to errors in the pixel state verification as there can only be a global ambient light sensor on the display that cannot take pixel to pixel variations of the ambient light intensity into account. This is eliminated by the consecutive measurement method described here.
The two measurements can be done closely space in time, where the front light 1005 is quickly flashed to the off state for the off measurement while it is on the remaining time or vice versa. Further is it also possible to use a scanning front light as proposed in FIG. 34 so that the measurement in the off- or on-state can be done in a scanning way to please the eye of the viewer. As a front light can generally be switched fast (i.e. 50 Hz or higher) the user does not need to see this as flashing, but more generally as a continuous light intensity (low if the front light is off or just below high when it is on).
Two consecutive measurements with a reflective system without a front light. In the case 1025 illustrated in FIG. 38, the first measurement 1026 is done with the regular image on the display, while the second measurement 1027 is done with the pixels switched to a known reference state. The second measurement 1027 where the pixels are switched to a known reference state result in a local measurement of the light intensity. This measurement can then be used to correct the first measurement for local fluctuations in the light intensity or to even discard a whole measurement if the lighting conditions were not good enough for a reliable state verification. It is also possible to even add more reference state measurements, such as a white and a black state reference measurement in order to increase the reliability of the verification. The measurements need to be done closely spaced in time in order to avoid temporal fluctuations in the light intensity to affect the pixel state verification. It is possible to make this multi-step verification measurement more pleasing to the eye of the viewer by doing the consecutive measurements pixel-by-pixel or in certain blocks of pixels in order to make the measurement less visible.
Two consecutive measurements with a transmissive system with a back light. In the case 1050 illustrated in FIG. 39, the first measurement 1051 is done with the lighting off, while the second measurement 1052 is done with the lighting on. The difference between the two signals corresponds to the ambient light contribution. This works similar to device 1000 described with reference to FIG. 37.
A combination of switching the front or back light on and off in two consecutive measurements (FIG. 37 and FIG. 39) with switching to reference states (FIG. 38) is also possible for transmissive or shutter based displays. This could further improve the ambient light measurement compensation on a pixel basis.
Two consecutive measurements with an emissive display. In the case of the display device 1075 illustrated in FIG. 40, the first measurement 1076 is done while all pixels are off (not emitting). During this measurement the local (pixel) intensity is of the ambient light. The second measurement 1077 is done while showing the image. In this case both the ambient light and the composite signals are measured. By subtracting the two measurements, the ambient light component can be compensated for. As emissive displays can typically be switched fast (i.e. 50 Hz or faster) the two measurements can be spaced closely in time. It is also possible to do the two measurements per pixel or per row or column of the display in order to make it more pleasing to the viewer.
Generally, the two (or more) measurements that can be used to subtract the ambient light contribution can also be used to detect lighting conditions that are not good enough to do a reliable measurement. In that case multiple actions can be taken. One of them could be to temporarily increase the intensity of the artificial lighting (front, back or self-lighting), in order to reduce the relative contribution from the ambient lighting. It is also possible to do the reference measurement of the ambient lighting multiple times instead of only one time in order to not only assess the spatial fluctuation of the ambient light, but also the temporal fluctuation. This can help to assess whether the lighting conditions are reliable enough. Accordingly, this also prevents tampering with the display by creating ambient light patterns that would result in errors in the pixel verification measurements.
Tamper-Proof Verification
In some cases, optical and electrical verification methods can be manipulated or distorted resulting in an ambiguous or even a wrong state indication to the tag or backend system while in fact the display was showing the correct information in a perceivable way.
Addition of a reference pixel. One or more reference pixels can be added that are switched in a predefined way during every verification cycle. For example, a display could have one reference pixel that is switched from white to black and back to white again during every measurement of the pixel state, as shown in FIG. 41. As this is a predefined switching cycle 1100 going through all possible optical states of a pixel, the measurement output for this pixel should also behave in a predicable way. By taking a measurement of the switching state at multiple points on the switching curve, the switching curve can be sampled. This should result in a smooth curve (i.e. the consecutive measurement should either be increasing or decreasing in value) with a certain minimum and maximum readout when the external conditions are good enough and constant enough for the measurements.
By doing the state verification of all other pixels in the display during the same time as the time it takes to measure the reference pixel, the quality of the external environment during the pixel verification can be verified. Of course it is possible to add multiple reference pixels at certain positions in the display. It is also possible to use certain pixels that are part of the display as reference pixels. In that case the pixels that are used as reference pixels should first be brought into a reference state and at the end of the measurement should be put back into the state that is part of the image that is displayed. Further, it is also possible to do the reference pixel measurement in different ways. For example, the switching curve could be sampled by switching the pixel to a number of states on the switching curve and keeping it in that state for a certain amount of time to do the measurement, before switching it to the next state to be measured, as shown in FIG. 42.
Switching curves. The switching curves of the pixels to be verified can be measured. This is especially useful for displays that are not bi-stable, such as LCD or OLED, as they are continuously driven. The pixels are switched from their current state to a certain reference state and then back to the current state again. The reference state can either be the full on or off state or a small difference compared to the current switching state such that the user can hardly notice the difference. During this time, not only the current state is measured, but also the reference state or even states in between the current state and the reference state. As the switching curve is known and smooth the multiple measurements should result in a predicable relative outcome. When the external environment is fluctuating in time or position or is in general not good enough to do the measurement reliably, the series of measurements will result in a switching curve that is not as predicted. The measurements can be done optically and/or electrically in ways already disclosed before.
Multiple consecutive measurements. By doing more than one measurement at different moments in time, it is possible to detect a fluctuating environment when the pixel state is constant. This can help to detect if external lighting or electrical conditions are fluctuating in time. For example, the verification of the pixel state can be done twice, closely spaced in time. When the two measurements differ too much the pixel state verification is not reliable. In that case another measurement could be done or a (error) message could be displayed, stored or sent.
Environmental sensors. By adding environmental sensors, such as optical sensors, electromagnetic radiation sensors, vibration sensors, acceleration sensors, etc. it is possible to sense if the environment is good enough to perform a reliable pixel verification and if the environment is not fluctuating in time. The sensors can be added to the display system and it is also possible to add multiple sensors of the same type at different locations. The sensors would be read-out before, during and/or after the pixel verification in order to ensure that during the whole verification measurement the environment was good enough and not fluctuating to reliably do the verification.
Combinations of measurement data. By combining multiple measurements, it is possible to greatly reduce the chance of tampering with the system. External sensor data, reference pixel data, optical pixel verification data, electrical pixel verification data, etc. could all be combined such the reliability of the measurement is increased. For example, sensors could be used before, during, and after the verification in order to detect if the external environment is good enough and stable during the verification. This could give data such as: the amount of external light is too low or too high or fluctuated over time or locally during the verification. Or it could detect a source of electromagnetic radiation that is too high to do reliable electrical measurements. Further, an optical verification system could be used to sense the amount of light reflected, emitted or transmitted per pixel, while an electrical verification system at the same time senses if the (switching or test) voltages put on the electrodes really reach the other end of these electrodes and also measures the capacitance of and/or the current flowing into each pixel. This combined information from multiple sources can make the system extremely robust against tampering.
Adding a static or dynamic watermark to the image. By adding a certain visible or even better an invisible pattern to the image that is displayed or to the update of the image, it is possible to detect tampering with the system. When the watermark cannot be detected, the system could well be hacked or be tampered with. As a response the system can then shutdown and/or a (error) message could be displayed, stored or sent.
The types of unique patterns can be any of:

- Final image watermark.
- A unique contrast modulation between parts (e.g. pixels or groups of pixels) of the display that could well be invisible to the viewer but measurable by the detection system.
- Watermark during the update of the image.
- A unique timing between the sequential update of several parts (e.g. pixels or groups of pixels) of the display.
- A unique modulation of the electrical signals (e.g. additional high frequency modulation, modulation in frame rate, AC/DC signal added to voltage levels, etc.).
- A sequence of image patterns displayed before displaying the final information. This sequence could also have a pattern of delays between the subsequent images.

For bi-stable displays especially the watermarking in the final image is useful. For non-bistable displays, such as LCD or OLED it is also very useful to add watermarking in the update. The unique patterns or watermarks can be stored in the system upon fabrication or be a generated pseudo random series that uses the unique system ID as seed. Alternatively, the unique pattern could be sent by the backend system to the system using any known way to make a unique one-time sequence.
Accordingly, the disclosed embodiments result in a display device where tampering can become virtually impossible during the verification process. For example, placing a mirror that is a bit off-angle in front of the display in order to create an ambiguous spatial fluctuation in the lighting conditions can be detected either by using a reference pixel that detects an abnormal response when switching, by measuring pixels in a number of different switching states, by measuring the switching curves of pixels, by external detectors that detect different light intensities at different locations or by using electrical measurements of the pixel state instead of optical. Using a source of electromagnetic radiation to create electrical noise for the measurements can also be overcome by detectors, reference pixels, measuring switching curves, or using an optical detection system. When complemented by watermarking, the complete system can become tamperproof.
An Optical State Monitor
The condition of goods can change over time, as a result of natural degradation and processes, due to environmental effects or mishandling, or for a wide variety of other reasons. Changes in the condition of billions of goods significantly impacts their use, outcomes, and value; collectively their utility. Today the condition of many of these goods is either unknown or if known, it is not immediately actionable by humans or systems where or when it matters most. A big part of the problem is 1) the cost of evaluating the condition of the good, 2) the time it takes to extract the good from its normal distribution channel to test its quality, and 3) that the good is often times remote from the entity that most needs information about its quality. Further, in some cases the destructive nature of existing methods of determining the condition of the goods makes testing to determine the good's condition economically unfeasible.
The term “goods” as used here, encompasses a variety of ‘things’ including those that occur naturally, are processed or manufactured, examples of which include: blood products and other biologics, fresh/raw/processed food and beverages, plants, animals and people, industrial liquids, chemicals and materials, water, solvents, distillates, fuels and other liquids, industrial/toxic waste etc. Goods are variously composed of liquids, semi-solids, solids (hard, soft, textured) gases etc., and may be in an almost unlimited variety of transparent, semi-transparent or opaque containers or, they may exist in the open (e.g. farm/field, pipeline, river, reservoir, lake, ocean, atmosphere etc.) free-standing, free-flowing or free-floating. Exemplary conditions of goods include

- composition, consistency, homogeneity
- the presence of impurities or contaminants, voids or bubbles
- the presence (or absence) of bacteria or organic matter
- the results of mixing, liquefaction, deliquescence, dissolution, disintegration, settling, melting, freezing, evaporation or sublimation
- the results of growth, decay, age, etc.

One unique way to assess the condition of a good is to subject a surface of the good to light or other electromagnetic radiation, and then evaluate the light or electromagnetic radiation that is reflected from the good's surface. It will also be understood that in some constructions of the optical state monitor, the electromagnetic radiation may be transmitted through the good or a portion of the good. Herein, the light or electromagnetic radiation that is reflected from the good's surface or transmitted through the good is referred to as the good's optical profile. This optical profile may be expected intensities at a specific radiation wavelength or wavelengths, or may be over a wide band of wavelengths. The optical profile of a good can be thought as spectral characteristics (e.g. discrete bands) generated in response to exposure to light or other electromagnetic radiation. By knowing the optical state profile for a class of similar goods (e.g. units of blood) and subsequently sensing or detecting the optical state of monitored sites of an individual good (e.g. a particular unit of blood) of the class of goods, the condition of the individual good can be determined (or verified) to be as intended or expected. An optical state profile for a specific good may be generated by optically measuring the monitored sites of the good prior to it being monitored (e.g. when it's condition is “new”) and may serve as a relative reference for determining the current condition of a good.
In this way, by testing or evaluating a particular good or class of goods at different instances of time, or continuously over one or more periods of time, an optical profile may be generated that indicates, for example, the optical characteristics for a good that is in an acceptable condition, has spoiled or is on the verge of going bad. Although such optical characterization or profiling may be useful at a single wavelength, additional useful information about the condition of a good may be determined by having two or in some cases several, different wavelengths evaluated. It will be understood that each good or class of goods may have an entirely different set of wavelengths and optical characteristics that characterize or profile it, and that can be used to determine its utility. In one particular embodiment, an optical state monitor has multiple monitored sites, with each monitored site monitoring for a different wavelength of electromagnetic radiation. By having multiple moderate sites on a single optical state detector, a robust optical profile of the good may be developed, enabling a much higher degree of confidence that the good is in an acceptable or unacceptable condition.
It will be understood, here and hereinafter, that the term frequency of the light source (layer) is interchangeable with the corresponding wavelength (in vacuo) of the light source (layer). Furthermore, the term single (or specific or particular) wavelength (or frequency) refers to the nominal wavelength (at peak intensity) of a substantially narrow bandwidth light source.
As the term is used in describing an optical state monitor, a good can be considered analogous to a display and the good's “condition” is analogous to the display's “displayed message”. Both can be determined using “light” (or more generally, electromagnetic radiation at wavelengths perceptible by humans or machines). The former, by measuring the “optical state” of “monitored sites” of the good and comparing them to the good's “optical state profile.” The latter, as fully described with regard to FIGS. 1-42, by measuring the optical state of the display's pixels or segments and comparing them to an intended message. Note that use of the terms “optical” and “light” are to be understood as not being limited to human visible electromagnetic radiation (wavelengths) and are used in part, to provide continuity with related patents and applications. Note further, that as with pixels or segments of displays, the size (area) and shape of monitored sites can vary according to the good (or configuration of the optical state monitor).
The optical profile of a good can be thought as spectral characteristics (e.g. discrete bands) generated in response to exposure to light or other electromagnetic radiation. By knowing the optical state profile for a class of similar goods (e.g. units of blood) and subsequently sensing or detecting the optical state of monitored sites of an individual good (e.g. a particular unit of blood) of the class of goods, the condition of the individual good can be determined (or verified) to be as intended/expected. An optical state profile for a specific good may be generated by optically measuring one or more of the monitored sites of the good prior to it being monitored (e.g. when it's condition is “new”) and may serve as a relative reference for determining the current condition of a good.
Described herein are inexpensive, generally self-contained, autonomously operable, devices, systems and methods for monitoring, determining and presenting the condition of goods. The devices will be described as optical state monitors. In a particularly useful embodiment of the optical state monitor, it is constructed as a self-contained thin device that has a light detection layer and a light source layer that are printable, flexible and inexpensive to produce, and that can be easily and confidently attached adjacent to a surface of a good. As will be more fully described later, the optical state monitor generally operates by having a light emitting portion or layer that emits light or other radiation toward the surface of a good, and has a light detection portion or layer that detects light or other electromagnetic radiation that is reflected from, or transmitted through, the surface of the good. The light detection layer is comprised of optical state detectors that, advantageously with the light source layer, are localized to what is being called individual monitored sites. In one embodiment, the monitored sites for the optical state monitor have thin, flexible arrays of light sensitive detectors within a “light detection layer” and one or more sources of light within a “light source layer” that are applied or coupled to, or located within goods. Of particular interest, are assemblies of light source and light detection layers that can be produced using high volume deposition or manufacturing processes (e.g. printing, ink-jetting, spray casting, vapor deposition/roll-to-roll).
An optical state monitor comprises an optical state measurement apparatus which is in turn comprised of a processor and memory, a light detection layer (and individual and groups of optical state detectors of which it is comprised) and typically an integrated light source layer (and light source or sources of which it is comprised). In addition, an optical state monitor includes a power source, and appropriate to the application, wired or wireless interface(s), visual (e.g. displays or state indicators) or acoustic interfaces, a clock or timer, actuator(s) and sensors, circuitry and physical structure (e.g. flexible (e.g. plastic, paper) or rigid (e.g. glass or metal) substrates/layers, boards etc. to support the components, circuitry, optical measurement apparatus etc. The power source may be for example, harvested electromagnetic radiation (e.g. RF, light, heat etc.), externally supplied electricity (e.g. wired or capacitive or inductive coupled), internal energy storage such as batteries or capacitors. The actuators as previously described herein and including wireless receivers (responsive to wireless signals), electrical and electro/mechanical switches, sensors and monitoring systems. The actuator may also be a light detector or light detection layer where the output signal passively generated by an external light source, activates circuitry within the optical state monitor (e.g. when the signal exceeds a set threshold).
Similar to the light detection layers previously described herein with reference to FIGS. 1-42, the light detection layer of an optical state monitor comprises one or more arrays of thin-film light detectors (optical state detectors), generally on a single substrate. Each optical state detector corresponds to a monitored site that may be considered analogous to pixels or segments, with the shape, pattern, size (area) and according to the good (and corresponding configuration of the optical state detector), dots, lines/bars, butterfly shapes (to accommodate curves). The material of which the optical state detector is comprised, is selected to be tuned to a particular wavelength or a band of wavelengths that are correlated to a detection of the condition of the good.
The light source layer for a monitored site generally comprises a light source and a light guide (typically edge-lit) that directs the light to the monitored sites and detection by the light detection layer. The light source is preferably one or more LEDs or OLEDs that support a single wavelength or multiple wavelengths inside or outside the human visible range. As is well understood in the art, the single wavelength refers to the nominal wavelength (at peak intensity) of a substantially narrow bandwidth light source. Beneficially, the light sources are tuned to the known spectral properties of the good that are useful for defining the condition of the good. Note that in some applications, the light source is external to the optical state monitor (e.g. ambient or applied or directed light). In this case, the optical state monitor typically would not have a light source layer. In some configurations that rely on an external light source, however, the light source layer might comprise a light guide, micro lenses or other means for directing or focusing the external light source on the optically monitored sites. The most common configuration of an optical state monitor will have a single light source layer comprised of a single light guide and one or more light sources (e.g. LEDs). Optical state monitors may however have more than one light source layer, or the single light source layer may be patterned to support multiple monitored sites.
As noted herein, methods and systems for determining or verifying a displayed message with an intended message and for determining the message (or displayed patterns) and associated message state independent of an intended message, with electrical signals corresponding to electrical properties of display pixels are described in U.S. patent application Ser. No. 14/927,098, entitled “Symbol Verification for an Intelligent Label Device.” These methods are useful in understanding the methods that apply to similar determinations regarding using the optical state sensor to determine condition of goods.
Methods and systems may be used with electrical signals that correspond to the optical states of the monitored sites of goods; that correspond to the intensity of reflected or transmitted light that corresponds to the optical states of monitored sites; wavelengths of reflected or transmitted light that corresponds to the optical states of monitored sites; or polarization of reflected or transmitted light that corresponds to the optical state of monitored sites. Those methods and systems may further use measures of ambient light or light emitted by a light source layer (e.g. reference sites, calibrated measurements). Those methods and systems may use electrical signals corresponding to the optical states of monitored sites with and without ambient light, pre and post activation of a light source layer or different combinations thereof.
Importantly, and especially in the case of goods with limited stability, electrical signals corresponding to the optical states of monitored sites are preferably stored along with the time or period the measurements are taken. As with electrical measurements of the electrical properties of monitored sites, optical measurements can be initiated in response to a variety of ‘events’ such as actuation, changes in location or environmental conditions or those of the good itself, elapsed or absolute time, or external signals/communications (e.g. via wired or wireless), etc. Similarly, the light source/light source layer can be activated in anticipation of, or in response to, a variety of ‘events’ and as appropriate, to precede, or follow the monitoring of the optical states of monitored sites.
Throughout the description of the state monitor, several types of additional information will be described generally as below.
An optical state profile is the profile regarding a particular good, or a class of similar goods, that indicates the expected electromagnetic radiation profile reflected from, or transmitted through, that good that corresponds to different conditions such as those previously described. The optical state profile may look at a single frequency, multiple specific frequencies, or a band of frequencies.
Measured optical data is a measurement of the electromagnetic radiation that has been reflected from, or transmitted through, a good's surface. More particularly for reflected light (and analogously for transmitted light), an electromagnetic radiation source will direct electromagnetic radiation toward the surface of the good, and a portion of that radiation will interact with the surface of the good, and cause a reflection from the surface of the good. A portion of this reflected electromagnetic radiation is captured by the optical state detector, and stored as the measured optical data. By comparing the measured optical data to the optical state profile, the processor for the optical state monitors may robustly determine the quality of the good. As used herein, the “surface” of a good may be an exterior face of the good, the exterior face of packaging for the good such as a clear plastic wrap, or may be an interior face. By way of example, an optical state monitor may be constructed that can be inserted into a good, such as a wheel of cheese, and the surface of the cheese that is monitored will be internal to the cheese wheel. In another example, an optical state monitor may be attached to the face of a bag of blood, such that the “surface” of the good is the plastic bag. In some constructions, the optical state monitor may be positioned to allow electromagnetic radiation to be transmitted through the good (e.g. a liquid medicine or blood) before detection. In some cases the light source may be ambient light, and in others may be a controlled-wavelength optical source as discussed herein.
It will be understood that the processor may implement rules and algorithms regarding how to compare the measured optical data to the optical state profile, these rules and algorithms may be set and defined a priori, or they may be dynamic based upon learned information. These measurement rules and algorithms may be referred to as an optical measurement protocol The optical state monitor device may include a sensor, such as a humidity sensor, temperature sensor, vibration sensor, or other environmental sensor. Based on information from one or more of the sensors, the processor may adjust and modify its rules and algorithms (the optical measurement protocol) with respect to how the optical measurement is taken, and how the measured data is compared to the optical state profile.
In one example, an optical state monitor is a self-contained device that can be attached to a good or otherwise positioned for detecting specific electromagnetic radiation, and confirming that the electromagnetic radiation conforms to predefined patterns and expectations. In this way, the self contained optical state monitor can be used to determine the quality of a good, the environment of the good has been distributed through, or another characteristic of the good. It will be understood that there are many other uses for a self-contained optical state monitor. In some cases, the self-contained optical state monitor may maintain information regarding the collected radiation in its own memory, and other embodiments the optical state monitor may wirelessly communicate the information to a remote monitor. It will be understood that the optical state monitor may act individually, or may act together with a collective of, or within a network, e.g. a peer-to-peer or mesh network, of optical state monitors to more fully and completely evaluate the state of a good. In other cases, multiple optical state monitors may be used, with each optical state monitor configured to monitor a particular part of the electromagnetic spectrum that corresponds to the optical state profile.
Generally, the optical state monitor operates by having a light source that can be directed toward a particular surface, such as an external or internal surface of a good or product. The light source may be selected to project particular wavelengths or quality of electromagnetic radiation, such that it will have a particular interaction with the good. Depending upon the characteristics or quality of the surface of the good, certain electromagnetic signals will be reflected back off the surface toward the optical state monitor. The optical state monitor also has a light detection layer that can receive the reflected electromagnetic radiation, and then send data regarding that reflected radiation to a processor. The processor then can compare the reflected radiation to patterns of expected reflection, and make a determination according to the quality of the good or surface.
In one embodiment, the optical state monitor has a light detection layer and advantageously an additional light source layer, both of which are typically electrically connected to a processor with associated components, thus forming a self-contained optical state monitor system. The light detection layer may contain multiple light detectors for detection of the optical state (or optical state detectors) of the good at multitude of monitor sites. Similarly, the light source layer may consist of multiple light sources with each light source providing electromagnetic radiation for a specific or several light detectors. In some cases, however, e.g. where there is sufficient ambient (natural or artificial) light available, a light source layer may not be necessary to confidently determine the optical state of the good. In other cases, e.g., when the good is enclosed in a container and/or external packaging which are not conducive of transmitting ambient light, a light source layer is required.
In order to detect the various conditions of the good corresponding to its optical state profile, the light sources utilized for illumination may be of multiple wavelengths or multiple wavelength ranges depending on the particular good and its characteristics (e.g. spectral response). For instance, one wavelength range may be suitable for detecting a particular condition of the good such as a particular type of bacteria, whereas a different wavelength is favorable for detecting certain contaminants of interest. The detectors may also favorably be tuned for the particular wavelengths of the light sources and the spectral or polarization response of the good in either reflection or transmission mode. As is well understood in the art, a particular wavelength refers to the nominal wavelength (at peak intensity) of a substantially narrow bandwidth light source. For certain goods, it may further be advantageous to modify the spectral response of the good by doping the good itself. This is particular useful if the dopant enhances the detection of a particular characteristic coupled to the state of the good (e.g., a dopant that favorably attaches itself to contaminants). It will be understood that the type of packaging for a good may affect its optical profile. For example, the optical profile for milk in a plastic jug will be different than the optical profile for milk in a cardboard container.
FIG. 43 illustrates an example of an optical state monitor 1200 showing a top view 1220 and a side view 1230. Cross-section line 1225 shows the relationship between the top view 1220 and the side view 1230. The optical state monitor as illustrated has six distinct monitored sites (1201, 1202, 1203, 1204, 1205, and 1206), each monitored site comprising a shared light source layer and individual optical state (light sensitive) detectors. It will be understood that more or fewer sites may be monitored by an optical state monitor. In this particular example illustrated in FIG. 43, the light source layer 1207 and the light detector layer 1208 are deposited on a substrate 1209 at the monitored sites, with desired shapes and areas (e.g. segmented or pixelated), suitable to detect the good 1210. The good may be enclosed in a container 1211, which preferably is transparent or semi-transparent at the light source and detection wavelengths of interest, with the substrate 1209 attached, e.g. using pressure sensitive adhesive (PSA) or transparent glue (not shown in FIG. 43). The light source layer may first be deposited onto the substrate followed by the light detection layer, as shown in FIG. 43. The light source layer may, for instance, be deposited via a printing or an inkjet process using OPV materials as previously disclosed. These materials may further be specific to each monitoring site (as illustrated in FIG. 43), allowing for an array of tuned responses of the detectors from the detected light (e.g. 1212) and monitoring sites of the good. Analogously, the light source layer 1207, which may consist of OLED materials, may also be deposited using similar processes (as previously disclosed), and tuned for a specific wavelength or wavelength ranges (e.g., 1205 has a different wavelength 1213 than the wavelength 1214 of 1204). Alternatively, the light source layer may consist of a light guide comprising edge illumination with one or several LEDs. This is particularly advantageous for configurations in which the light source is positioned in-between the detector and the good as the unidirectional illumination eliminates the bias effect on the detector. Note that the bias effect may be alleviated for cases in which the reflected/transmitted light wavelength is shifted from that of the light source due to the properties of the good or by intentionally adding dopants to the good (with e.g. phosphorescent or fluorescent properties).
The substrate 1209 of the monitor favorably consists of a thin flexible material (e.g., PET, PEN, polyimide, PMMA, or polycarbonate), such that the optical state monitor can be fabricated using roll-to-roll methods and subsequently conform to the shape of the good or an advantageously shaped detector array for application around or inside the good. Depending on the application and configuration, in some cases the optical state monitors may be combined on to a single monitor substrate wrapping around the good of interest with the processor and associated components some distance away (e.g., if equipped with a visual interface). In other cases the processor and associated components may favorably be included on the monitor substrate. Each light source and light detection layer may also have its own respective substrate which may be later be combined to the optical state monitor. The substrate may also be temporarily and only used during the manufacturing process (e.g., using a transfer process) of the optical state monitor.
There are many different possible stack configurations of the detection layer and the light source layer in relation to the good. Some configurations are advantageous for determining the state of the good in the bulk, or for determining the state of the good based on either reflection or transmission mode, or combination thereof (to determine absorption). Others, such as those favorable for detecting from the outside through a container or a through a port of the good (both substantially transparent in the wavelength range of interest), are analogous to determining the optical state and optical state profile of a display previously disclosed. However, there are differences: One key difference is that is that the good (as opposed to a display) typically does not need to be visually inspected at the monitored sites since they may only have a small collective total area as compared to that of the boundary area of the good. This allows for monitor substrates which are opaque. A second difference is that the necessary resolution of light detection for goods may be significantly lower than that of a high resolution display. Thus configurations are possible in which the detection layer is located further away from the good, allowing for integration of light source layer in-between the good and the detection layer (as shown in FIG. 43). Furthermore, this allows for light detectors that are non-transmissive. For example, back electrodes generating higher detection efficiency are possible (as opposed to a largely transparent electrode), as well as, other highly light absorbing materials for the photosensitive layer can be utilized. Such materials, in addition to more efficient OPVs, include inorganic PV materials which could also be deposited via spraying or printing (e.g., inorganic nanocrystals with surface ligands such as colloidal cadmium selenide nanocrystals capped with the molecular metal chalcogenide complex).
FIG. 44 illustrates a detailed side view of the optical state monitor reflection configuration exemplified in FIG. 43 using a light guide. The optical state monitor 1300 encompasses for illustration purposes two sites: a First Site 1301 and a Second Site 1302. The light source layer 1304 is attached the good 1305 directly 1306 or optionally onto the container 1307, with an adhesive 1308. It should be understood, here and elsewhere within this disclosure, that the cladding layers for the light guide plate 1315 are for simplicity not shown and are, for discussion purposes, part of the light guide (to achieve total internal reflection with a lower refractive index of cladding layer relative to that of the light guide substrate). The light detection layer 1303 of this configuration is based on a photoactive layer 1309 with its electrodes 1310 and 1311 manufactured on a separate substrate 1312. A significant advantage of this configuration is that the transparent and non-patterned electrode 1310 can be deposited first onto the substrate 1312 followed by deposition (e.g. printing) of the (optionally) patterned photoactive layer 1309 and the patterned (e.g. opaque) electrode layer 1311. The light detection layer is further environmentally sealed by a barrier layer 1313, which may also optionally be opaque, in order to prevent any ambient light illuminating the detector, and barrier/adhesive layer 1314 on the opposite side. Note that the light detection layer 1303 and the light source layer 1304 can be manufactured separately and later merged advantageously in a roll-to-roll process. A patterned application (e.g. printing) of the photosensitive layer 1309, allows for selectively depositing photosensitive materials (1316 and 1317) which are tuned for the particular characteristics of the optical state detection and favorable optical state profile of the good in conjunction with light source. The light source, may be tunable for different output wavelengths, or may consist of multiple light sources as illustrated by Light Source 1 1318 resulting in emitted light 1320, as well as, Light Source 2 1319 resulting in emitted light 1321. Note that both light sources could advantageously illuminate the good both at the First Site 1301 and the Second Site 1302 by light 1322 and 1323, respectively, by redirection of the light guide plate 1315. The resulting reflected light from the monitored sites of the good, 1324 and 1325, respectively, subsequently is detected at the light detection layer 1303 resulting in a state detection signal (e.g. voltage or current) 1326 and 1327, respectively. Note that for goods that are contained in relative thick containers it may be advantageous to insert a focusing layer (e.g. microlens layer) in-between the good and the detector, in order to increase the resolution of the (imaged) surface of the good onto a (higher resolution) segmented/pixelated light detection layer for more detailed measurements. Furthermore, it may be preferable to add additional layer enhancements to the light detection layer, such as notch of edge pass optical filters, in particular for filtering out ambient light or for cases in which there is a shift in wavelength between that of the emitted light from the light source layer and that of the received light at the light detection layer (e.g. goods with, e.g., fluorescent or phosphorescent properties, as discussed below).

EXAMPLE 1

It will be understood that the optical state monitor may be constructed for attaching to particular products or services. Often, the surfaces of a product for good to be monitored may be constructed in a different physical shape, or have different types of materials. Accordingly, the optical state monitor construction may be adjusted to adapt to the particular good or product that is intended to be monitored. For example, a good or product surface may have a flexible optical state monitor that is particularly useful for conforming to curved geometries. One such geometry is a tubular (or cylinder) form 1400 as illustrated in FIG. 45, in which the tubular optical state monitor 1401 is positioned inside the good 1402. The good may further be enclosed in a container 1403, which may be opaque or (semi-)transparent to allow ambient light to pass through. The optical state monitor 1401 may, for instance, be configured for reflection mode measurement of the good as shown (e.g., using the reflection configuration of FIG. 44) with the ability to emit light 1404 from the light source layer in the optical state monitor, and receive the subsequently reflected light 1405 from the good by the light detection layer of the optical state monitor. The detection and source layers may both encompass the entire circumference of the tube, or may have a small gap (seam) 1406 for flexible electrical connections to the processor and associated components (not shown).
Depending on the good the optical state monitor may be configured with bands along the perpendicular (axial) dimension such that different wavelengths of light sources and/or different spectral response characteristics of light detection layers can be incorporated. Furthermore, the circumferential direction may also be segmented or pixelated. The tubular optical state monitor may also optionally be attached (e.g. via an adhesive) to a cylindrical support structure 1410, or be inserted into a tubular enclosure 1407 (e.g., a “vial-shaped” glass structure) to provide a protective barrier for a chemically reactive good. For cases in which the good 1402, the container 1403, and the enclosure 1407 are at least semi-transparent, ambient light 1408, may provide sufficient transmitted light through the good 1409 for a transmission detection of the good. Note that this detection could be obtained, e.g., using the same (reflection) configuration shown in in FIG. 44 (without enabling the light source layer), or by providing dedicated detection sites of the monitor without a light source layer. Furthermore note that the optical state monitor configuration shown in FIG. 45 could also be inverted to optically determine the state and condition of a cylindrically shaped good in reflection mode.

EXAMPLE 2

For transmission mode detection of goods which are semi-transparent (translucent), it is advantageous to utilize an optical state monitor which provides controlled illumination internal to the monitor (as opposed to ambient light such as sunlight). FIG. 46 illustrates an optical state monitor with a “wrap-around” geometry 1500, in which the flexible optical state monitor 1501 is wrapped around a partial circumference of a cylindrically shaped good 1502. Again, the good may be contained in an at least semi-transparent and rigid container 1503. The circumferential extent of the optical state monitor is preferably at least such that the light source and monitor (detection) site are diametrically opposed (i.e., approximately half the circumference), in order to maximize the transmitted light 1507 towards to detector 1504. For the configuration shown in FIG. 46 it is particularly preferred to use a transmissive and flexible substrate which also functions as a light guide plate for the light source layer. This enables placing the light source (e.g. as shown here LED(s) 1505) near the outcoupling region 1506 of the light guide plate (e.g. by embossing the appropriate side of the light guide) at one end and the detector 1504 at the other end.
FIG. 47 shows an exemplary transmission configuration of the optical state monitor 1600, in which the light guide 1601 of the light source layer 1603 at the source location 1605 is advantageously used as the substrate for the photoactive layer 1602 (or 1309 in FIG. 44) at the monitor (detector) location 1606. The light detection layer 1603 is further environmentally sealed by the barrier layer 1611, as previously discussed, and barrier layer 1604 on the opposite side (optionally at the source location 1605). The optical state monitor attaches to the good 1608 directly 1609 or optionally onto the container 1610, with an adhesive 1607. In this transmission configuration the light source 1612 edge-illuminates the light guide plate 1601. The outcoupled light 1613 then propagates into the good 1609 at the source location 1605, propagates through the good (presuming a substantially curved light guide plate 1601 as discussed above), and is detected by the light detection layer 1603 generating an electrical response 1614, as previously discussed. It may be advantageous to further design the outcoupling region of the light guide 1601 at the source location 1605 such that largely collimated light 1615 is outcoupled and further include a focusing layer (e.g. microlens layer in-between the light guide and the good 1609), in order to maximize the light received by the light detector 1602. Additionally (or alternatively), a polarizer at the light source layer and an analyzer at the light detection layer may be added to detect polarization properties of the good (e.g. birefringence).
The transmission configuration in FIG. 47 could also be applied to soft goods or liquids provided in thin/flexible containers, such as, e.g. blood or platelet bags. However, in such cases the distance between the spatially separated light source and light detection layers is not fixed, thus influencing the amount of light received by the detector and ultimately the optical state. Advantageously, the optical state monitor may be augmented by another source and detector functioning as a proximity sensor and respectively located in close proximity to (and thus approximately coplanar with) the source and detector. By further selecting a wavelength for which the good is largely transmissive the distance can be determined (e.g., algorithmically) and be used to normalize the transmission measurement with in order to establish the optical state (e.g., absorption coefficient of the good). For the configuration shown in FIG. 47, this could for instance be achieved by adding another light source LED 1612 with appropriate wavelength, and another segment/pixel with a tuned composition of the photosensitive material in the light detection layer 1602. Note that such a proximity detector could also indicate if the container has changed shape (and thus been moved around).

EXAMPLE 3

An alternative optical state monitor configuration for transmission mode detection of goods, which are semi-transparent (translucent), can be achieved by a wound geometry 1700 placed within the good 1701 as shown in FIG. 48. In this configuration the light detection layer 1706 receives light from one side and the light source layer 1703 emits light from the other side of the optical state monitor (both in the inward radial direction). Although there are many stack configurations possible, the light detection layer (e.g. of OPV or inorganic PV materials) could, for instance, be deposited (as shown in FIG. 48) on one side of a common opaque substrate 1704, with the light source layer (e.g., OLED based, or separate light guide substrate with LEDs) attached to the other side. The opaque property of the substrate 1704 enables that only light 1705 originating from the light source layer 1703 is detected by the part of the (segmented) light detection layer which located inside the winding 1706. The optional (segmented) part of the light detection layer located on the outermost part of the spiral 1702 predominantly detects ambient light 1707, which has propagated through the at least semi-transparent container 1708 of the good.
A key advantage of the configuration shown in FIG. 48 is the ability to control the extent of the void 1710 filled by the good in-between the light detection layer 1706 and the light source layer 1703 for consistent transmission (or more specifically absorption) measurements while optical state monitor still manufactured on a single substrate (advantageously using a roll-to-roll process). The winding may for example be held in place by grooved opaque end pieces (not shown in FIG. 48), which may further fixed by, e.g., stand-offs. The spacing may be adjusted over different revolutions of the winding to optimize the detection at different wavelength ranges, or to detect at higher resolution over large variations of specific properties of the good (e.g., absorption coefficient as the good is aging, such as, sediments in wine).
An exemplary planar (unfolded) layout of the optical state monitor in FIG. 48 is shown by 1800 in FIG. 49 (for simplicity, electrical connections and other components are not shown). The left side 1801 of FIG. 49 shows the (radially) outward facing side containing also a vertically segmented light detection layer 1803, and the right side 1802, also facing outward, shows a segmented (outlined) light source layer 1804 behind the opaque substrate 1805. The first index (dashed line) 1807 corresponds to the starting point of the inward winding spiral (also 1709 in FIG. 48), and the second index 1808 corresponds to the first full revolution of the wound optical state monitor. Note that in the wound configuration, the vertical light detection layer 1803 column predominantly receives ambient light, and may have different spectral response than that of the vertical light layer 1809 column, which predominantly receives light from the vertical light source layer 1804 column (second revolution of the spiral). The segment size of the light detection layer 1809 column may also be smaller than that of the light source layer 1804 column, to create more uniform illumination across each detector segment and to reduce crosstalk from neighboring light source segments (e.g., if detection is done in parallel). Optionally, the substrate 1805 may contain a series of cutouts 1810 (e.g. slits) in order to assure better correlation between the properties of the good inside the spiral wound optical state monitor and that of the outside (e.g. through diffusion or flow).
Depending on the properties of the good, the wound optical state monitor configuration may be inserted into a soft penetrable good or immersed in a liquid good. It is preferred to encapsulate the optical state monitor with a barrier layer, as discussed in the other configurations above, and possibly to further enclose it with a rigid transmissive material (e.g. plastic or glass). Furthermore, for certain goods in containers, the optical state monitor 1800 could favorably be attached into the cap of the container, as conceptually shown by 1900 in FIG. 50 (cutouts 1810 not shown). One end of the spiral wound optical state monitor 1901 is attached to the bottom of the cap 1902, with the other end preferably able to reach near the bottom of the corresponding container (when the cap is screwed on). The vertically segmented light detectors 1903 (and source layers) may span the entire length of the spiral wound optical state monitor allowing for detection of the fill level of the good in the container. The associated measurement apparatus could also determine if the good has (inadvertently) not been placed in an upright position, with the processor and associated components integrated into the cap 1902. Additionally, the cap may on top be equipped with a status indicator 1904 (e.g. fill level) or a state indicator 1905 (e.g. indicating if the good is in an acceptable condition) as determined by the self-contained system. Although not presented in the figures, an optical state monitor may also be constructed in a spherical geometric configuration.
FIG. 51 illustrates an exemplary method 2000 of determining the condition of a good analogous to a method for determining the state of a display presented in U.S. patent application Ser. No. 14/927,098, entitled “Symbol Verification for an Intelligent Label Device”. In one example, an optical state monitor is configured as an intelligent label and positioned on the surface of a good. In method 2000, an optical state profile (OSP) is stored in a memory of the optical state monitor as shown in block 2002. It will be understood that such profile and optical measurement protocol (described below) can be generated and stored in a wide variety of ways. Block 2008 shows the optical state monitor measuring the optical state of the good with the light detection layer (array of photosensitive detectors), advantageously with a light source layer. The optical measurements taken are responsive to the processor executing the optical measurement protocol. Block 2010 shows the processor comparing the optical measurements to the optical state profile. In the example, the condition may be contamination, age or physical ‘state’ etc. It will be understood that the type of condition can vary greatly within the confines of the described invention.
Each of the optically monitored sites can now be evaluated to determine if they, individually, in groups or collectively are of the intended condition (or not). That is, it can be determined if the condition of the good (or specific sites of the good) is as intended, has changed or is changing, and how close to the intended condition it is. Accordingly, as shown in block 2012, the optical states of the monitored sites can be compared to the corresponding optical state profile or the previous optical states of the individual monitored sites, of combinations thereof. In this way, it may be determined if the condition of the good, is as intended and if not, how it is different. For example, if the optical states of all the monitored sites are as intended, then the condition of the good is as intended. If a few of the monitored sites are not in their intended state, it may be determined that although not perfect, the condition of the good is still acceptable. In other cases, the differences between the intended optical states of the monitored sites and the actual optical states of the monitored sites may be so significant that it is determined that the condition of the good is not acceptable, or otherwise of diminished (or enhanced) utility. In making this determination, it may be useful to determine a subset of monitored sites that are actually necessary for generating a meaningful or trustworthy determination. For example, particulate within a liquid (e.g. wine) may have settled at a limited number of monitored sites in a container (bottle) that correspond to its current orientation, but that do not reflect the overall condition of the liquid. The same consideration could apply to optical monitoring apparatus/systems placed inside or outside the container (or the good itself). In another example, a good is damaged at one monitored site (e.g. corner of a box containing the good is crushed) that by itself doesn't represent the overall utility of the good. That is, the optical state of the one monitored site creates little or no ambiguity, or loss of confidence, in the determination of the condition of the good and hence its utility.
In general, as indicated by block 2016 optical measurements of monitored sites can be used to determine a level of confidence in the condition of a good, and once determined, the results of the determination can be stored for later use, may be transmitted to a third-party, may set a visual or wired or wireless alarm, or maybe used to initiate new optical measurements (e.g. at a different monitored site, with a different wavelength, or with a detector tuned to a different part of the electromagnetic spectrum).
For example, if method 2000 determines that the condition of a good has been diminished below a threshold, the intelligent label may locally cause a display to present a large red dot showing that there is a severe problem with quality. In a similar way, the label may cause an alarm or message to be sent to a third party, and an indication of the condition of the good as well as that of the red dot, may be stored for later use in verifying what message or information was available to user at a specific time. This may include verification or determination of the displayed message as described in US. patent application Ser. No. 15/368,622, filed Dec. 4, 2016 and entitled “Optically Determining Messages on a Display”. As illustrated by the arrow from block 2016 to block 2008, this process can be used multiple times to determine what the actual condition of a good was at various times throughout the distribution and use cycle of the good. An appropriately configured optical state indicator may also in block 2016 use the results to present information audibly. An appropriately configured optical state indicator may also present information visually using the light source layer (e.g. generate a flashing light or color).
In applying method 2000, it will be understood that algorithmic comparisons can compensate, adjust and account for errors in the measured results. Error correction techniques may also be applied. Confidence values or indexes may be generated or employed using the measured values, the importance of particular monitored sites to the ambiguity or uncertainty of the information, the accuracy of the information (and the benefits and risks of actions taken, or not, accordingly). In some instances, the comparison of measurements corresponding to the intended and measured condition of the good will be advantageously conducted off the label at the network level (e.g. to enable 3rd party verification/auditing).
The optical measurement protocol comprises the rules, logic, algorithms, parameters, tables or data, permissions, variables etc. (including those previously described herein) that are used by the processor to control the optical measurement apparatus of the optical state monitor. Appropriate to the good, the optical state monitor and other considerations, the optical measurement protocol determines the optical measurement of the monitored sites, for example the time/date, frequency, duration of the measurements, measurement of the output of individual or groups of light detectors to be measured (and thus the monitored sites) and depending on the optical state monitor apparatus configuration, the light source(s). Accordingly, the optical measurement protocol may store the raw optical measurements of the monitored state sites, or preprocess and store the optical measurements according to their intended usage (e.g. determination or verification of the good's condition or utility, or other purpose). The optical measurement protocol for example, may stipulate that specific instances of optical state measurements of optically monitored sites are taken and stored at specific times, or the optical measurements are pulsed or continuous over set intervals, integrated and then stored. Depending on the configuration, the optical state measurements may advantageously be taken at multiple monitored sites at the same time.
The optical measurement protocol determines the responsiveness to, and actions of, the measurement apparatus to actuators (such as those described in co-pending U.S. patent application Ser. No. 14/586,672, filed Dec. 30, 2014 and entitled “Intelligent Label Device and Method”), wireless and wired signals (also configurable as actuators), clocks/timers, location beacons/services, monitored ‘events’, user/custodian input, previous optical measurements results, and other means and methods of initiating measurement of the monitored sites. In a simple embodiment, the optical measurement protocol initiates an on-demand measurement responsive to an external signal. The optical measurement protocol is typically stored in the memory of the optical state indicator, where it may be modified advantageously according to circumstances and embedded permissions.
Referring know to FIG. 52, method 2025, which is similar to method 2000 described with reference to FIG. 51. Accordingly, only the differences between method 2025 and method 2000 will be described. As compared to method 2000, method 2015 includes the the addition to block 2029 of storing into memory the optical measurement protocol. In this way, the method 2025 stores information on the characteristics, conditions, and any anomalies found in the optical detection method. In this way, this information may additionally be used to process algorithms indicating whether or not the good is of quality, and may also be communicated externally to provide additional information regarding the detection process. By storing and using the optical measurement protocol, an additional level of robustness may be enabled in the optical state detector.
In addition to knowing the condition of a good, it is often advantageous to know any change to the good's corresponding utility, e.g. the adjusted economic value or price of the good, its remaining shelf-life, fitness-for-purpose based on its condition. An optical state monitor can be configured with a conditional utility profile (or one can be accessed remotely) for this purpose. Accordingly, different methods can be employed to determine the utility of a good. FIG. 53 illustrates exemplary method 2050 that is a useful extension to methods 2000 or 2025. Block 2052 shows the conditional utility profile being stored in memory. A conditional utility profile, for example, may have a price profile of a good corresponding to its level of bacteria, degradation, freshness, or other characteristic measured by the optical state monitor. It will be understood that a wide variety of economic characteristics may be attached to particular optical states relating to a goods actual current quality. Method 2000 or 2025 is then implemented as show in block 2057. The stored results of method 2000 or 2025 are then compared to the conditional utility profile in block 2061. The utility of the good is then determined in block 2067 and used as appropriate in block 2071. Note that the determination of utility, may take into consideration a confidence measure (degree of ambiguity or uncertainty) generated by the results from determining the condition.
An Optical State Monitor with an Indicator-Sensors
Disclosed now are optical state monitors augmented by or further comprising one or more optical state “indicator-sensors”. As will be described herein indicator-sensors are thin-film devices positioned proximate a good (or environment of interest) and adjacent to optical state detectors, and in the path of electromagnetic radiation reflected by or passing through the indicator-sensor. The latter including for example, electromagnetic radiation reflected or emitted by, or passing through a good or environment.
Indicator-sensors comprise a material or combination of materials whose optical state(s) changes (‘self-switches’) in response to a condition or characteristic of the good or its environment (e.g. temperature, the presence of bacteria or mold, a toxic chemical or a gas). According to the optical state monitor's predetermined optical state profile, the detected electromagnetic radiation (e.g. that is reflected by an indicator-sensor, or originates in a good or environment and passes through the indicator sensor) can be used to determine a measure indicative of a condition, characteristic, quality or utility of the good, the environment and/or the optical indicator-sensor itself.
The optical states of the indicator-sensor may be human (or machine) visible thus providing an observable visual indication of a change in the state of the good (e.g. it's spoiled or been contaminated) or of the indicator-sensor (e.g. that it needs to be replaced). It is to be understood that the singular use of the term sensor-indicator may refer equally to a single sensor-indicator or sensor film/layer or other construction comprising a plurality of individual indicator-sensors. And further that the singular use of the term optical state profile should be understood to, appropriate to the context (e.g. an optical state monitor having a plurality of different types indicator-sensors or optical profiles/signatures of interest), also refer to a plurality of optical state profiles.
In general an indicator-sensor comprises a material or combination of materials (layered, composite) that switches from a first optical state to a second or to a plurality of optical states in response to changes in the good or its environment. As is the case of the optical state detection (light detection) layers disclosed above, of particular interest are indicator-sensors that are thin, flexible, patternable (e.g. for a multitude of indicator-sensors of different types and/or spatially separated locations (e.g. in or across the surface of a good)) and printable (or otherwise deposited), as films or additive layers to the light detection or light source layers or other structures. Some indicator-sensor layers may be advantageously shared with other layered parts of the optical state monitor (e.g. substrates, focusing layers, electrode layers, conductive polymer layers, etc.). Others may be compartmentalized (e.g. further containing reactive materials), removable or disposable (e.g. for activation of the indicator-sensor at the point of use).
A single indicator-sensor may be configured or aligned with one or many optical state detectors. For example, where a single thin-film indicator-sensor spans a large area and the materials within the indicator-sensor optically change at locations that correspond to non-uniform changes the condition of the good or environment, and the optical state detectors are positioned/patterned to detect changes at a plurality of locations in the indicator-sensor. Alternatively, one or more indicator-sensors may be configured or aligned with a single optical state detector. For example, so that the cumulative of effect of changes to a good sensed by a thin-film comprising a plurality of indicator-sensors of different types (e.g. ‘tuned’ to optically change in the same or different ways to the same or different changes in the good or environment) that can be monitored and their optical state(s) detected and determined.
An optical state monitor may comprise a mix of optical state detectors of which some are augmented or comprise, or are otherwise configured with, indicator-sensors, while others are not. This would allow the optical state monitor to detect, and evaluate the results of the detection, of electromagnetic radiation directly or having passed through a (favorably co-located) indicator-sensor.
Indicator-sensors may be configured as a film (or other fit-for-purpose form) separate from, but designed to cooperate with, an optical state monitor. For example to be applied in or on the surface of a good at one time, and the optical state monitor applied to the indicator-sensor film at a later time. Or the reverse, for example when the optical state monitor (or the good to which it is attached) is fixed/stationary and an indicator-sensor film is applied and later removed and replaced. Of favorable interest are configurations of optical state monitors comprising in whole or in part, thin films/layers (e.g. optical state detector, indicator-sensor, light source, electrodes, substrates etc. layers) fabricated using additive manufacturing processes in sheet-to-sheet (S2S), roll-to-sheet (R2S), or roll-to-roll (R2R) formats. While indicator-sensors are generally described herein as thin, flexible films it is to be understood that they may take other forms including rigid, semi-rigid, semi-flexible, and may be solid-state, or combinations thereof.
An indicator-sensor comprises a sensor interface to a good or “thing”—an item, or the environment to be sensed or monitored, and a detection interface to the light detection layer of an optical state monitor. In some embodiments the sensor-interface and the detection interface may be the same.
Sensor-indicators may be additive to, or distinct from, but physically or via electro-magnetic radiation propagation path (e.g. light path) associated with or coupled to, the optical state monitor, e.g. laterally displaced (or displaced from), vertically distinct (e.g. the indicator sensor located through a container window of a good, or on opposing side of a good), laterally integrated (e.g. in a segment of an optical state monitor comprising a plurality of segments), or vertically integrated (e.g. in a single stack). A sensor-indicator may be configured fit-for-use, e.g. for single or multi-use or to be attachable, detachable, connectable, disposable, swappable, or replaceable; in the form of a label, sheet, film, card, patch, tag, tube, probe, package, container, product etc.; standalone, freestanding, or integrated with, attached or coupled to an item; stationary, transportable or mobile. It may also be configured to detect tampering or unauthorized ingress or egress, e.g. wherein the optical state monitor is configured with one or more indicator-sensors (advantageously of one or more types) to detect electro-magnetic radiation or other environmental condition (e.g. where the indicator-sensors react to the presence of a gas or liquid) inside a container or other physical space (e.g. a cabinet, closet, room etc.). And further for example, to be constructed as a freestanding assembly, wall/structure mount or combined with an adhesive (e.g. as a tape or label), and fit-for-purpose further configured with wireless or other communication means to alert/alarm.
The sensor interface and detection interface of the indicator-sensor also may be favorably configured in various ways. For example, the detection interface (read by the light detection layer of the optical state monitor) may be situated at or proximate a single side (surface), on the same side as or opposite side of the sensor interface, or on both sides. Furthermore, the detection interface may commonly face the light detection layer of the optical state monitor, for example: vertically integrated (in a stack), e.g. coupled to the light detection layer (see e.g. Example A below); vertically distinct from the light detection layer, e.g. separated by a common substrate (e.g. a “window” or transparent container of a good), the good itself (see e.g. Example B below); or laterally integrated with the light detection layer, e.g. on a common substrate (optionally acting as a waveguide, see e.g. Example C below).
In other configurations the detection interface (read by the light detection layer of the optical state monitor) may be facing the same direction as that of the light detection layer of the optical state monitor, e.g. with the detected electro-magnetic radiation (re-)directed from the indicator interface to the light detection layer, e.g. via a waveguide (substrate or fiber) with appropriate in/out-coupling regions, a reflector (e.g. mirror), or reflective grating. An optical state monitor may additionally be configured with the indicator-sensor comprising a combination of above configurations.
In certain configurations (at the detection wavelength range of interest, human or machine detectable) the indicator-sensor is transparent and the optical change of the indicator interface occurs at or proximate one surface (interface) and is detectable through the other surface (interface). Additionally, the sensor interface and the detection interface may be individually or collectively patterned, solid, interlaced, interspersed, layered, stacked, or surface textured.
Functionally an indicator-sensor self-generates an optical profile (optical signature) or other detectable change in its optical state in or at the detection interface (and in some cases the sensor interface surface as well) in response to, or indicative of, a change in (e.g. concentration, distribution, accumulation, etc.) or the presence or absence of a particular stimulus, catalyst, chemical or biological agent etc. e.g.: a substance, external (or environmental) or of the good (e.g. chemical, organic e.g. mold, fungus, virus, bacteria, blood, etc., in gas, liquid, or solid form); an environmental condition or physical state of the good (e.g. temperature, humidity, radiation (e.g. alpha, beta, gamma), stress, force, pressure, orientation, tilt, etc.); a physical force applied to the sensor-indicator (coupled to the good), e.g. speed, acceleration, vibration, shock, impact, force, pressure, torque, or compressive or tensile stress, etc.; or a combination of the above.
Some exemplary indicator-sensor types include: (a) physicochemical with e.g. an optical, electrochemical, electro-chemo(-luminescence) transducer (e.g. further in combination with a sensitive biological element e.g. tissue, microorganisms, organelles, cell receptors, enzymes, antibodies, nucleic acids, etc., that interacts with, binds with, or recognizes the substance of interest); (b) chemochromic of sub-types acid-base, oxidation-reduction, complexometric, adsorption, and chemiluminescent, etc. (e.g. pH indicators); (c) optical biosensors, e.g. using label detection methods (e.g. further using fluorescent, isotopic, chemiluminescent, electrochemical active probe, or nanoparticle labeling), advantageously label free detection methods, e.g. Surface Plasmon Resonance (SPR) (e.g. planar wave guide substrate, cladding layer, with TIR and evanescent wave through metal film (Au) to detect good/medium; edge light coupling; edge detection or outcoupling from planar wave guide to planar detector, or “flat bundle” of optical fibers, with cladding layer removed and replaced with metal film further exposed to the medium (e.g. good or ambient) to be detected, (d) amperometric biosensors incorporating an “optical state” transducer (e.g. an electrochromic layer), (e) radioactive dosage indicators, (f) color strain sensors, (g) tilt, shock, impulse indicators, (h) thermochromic indicators, (i) time-temperature indicators (TTIs), (j) other freshness or integrity indicators, (k) humidity indicators, (l) force (e.g. touch) or pressure indicators (e.g. for high pressure sterilization or pasteurization; e.g. ruptured microencapsulated dye systems or cholesteric liquid crystals), or (m) other mechanical-based indicators (e.g. micro-opto-electro-mechanical systems—or MOEMS-based). The sensing modalities of above exemplary sensors-indicators may further be categorized as real-time (instant or near instant indication), integrating (e.g. radiation dosimeter), reversible or irreversible (e.g. tilt, drop, shock), and passive or active (requiring an energy source).
The optical profile or change in the optical state of the detection interface (detected/measured by the optical state monitor) may include properties of reflectivity, transmission, transreflectivity, diffraction, refraction, scattering, wavelength (e.g. fluorescence), etc. The interrogating electro-magnetic radiation for detecting the optical profile or state of the detection interface by the light detection layer of the optical state monitor (described above) may include sources from: ambient light (e.g. sunlight or artificial room light), the optical state monitor (if equipped with a light source layer), a separate integrated light source within or coupled to the indicator-sensor, or a combination of above (e.g. at different wavelengths). The light source(s) may further be a coherent source (e.g. laser diode) or incoherent source (LED, or OLED) in continuous wave or pulsed operating mode, areal or point source, monochromatic or polychromatic (e.g. narrow or wide bandwidth) type, and may be enhanced with a focusing layer (e.g. a micro lens array) or a chromatic (e.g. optical notch or high/low wavelength cut-off filter) or polarizing layer.
The detection and measurement of the optical profile of a detection interface is analogous to that discussed above for detecting and measuring the optical profile of a monitored site of a good. The optical profile of the detection interface of the indicator-sensor is indicative of a condition, characteristic, quality, or utility measure of the good or ambient conditions (that may further affect the condition, characteristic, quality, or utility measure of the good), thus instead of in addition to being able to measure multiple monitored sites of the good, an individual or multiple indicator-sensor detection interface(s) are can be monitored and measured, wherein the indicator-sensors may be of same or different types and be coupled to the same or different locations of the good.
Measurements across all or selected areas of, detection interfaces of a set of indicator-sensors may favorably be averaged, weighted, filtered—spatially and/or in the time domain (e.g. delta, rate of change, absolute or relative measure/value, statistical methods, self-learning or AI, etc. may be utilized). Additionally, the measurements may be performed at pre-determined, or fixed sample rates and locations, or may the may be dynamic, adaptive or on-demand.
It should be noted that the previously discussed methods of determining the condition of a good (or determining the state of a display) are also analogous to determining the condition of a good utilizing an optical state monitor with an indicator-sensor. Note, however, that in reference to methods 2000 and 2025 (illustrated in FIGS. 51 and 52, respectively), for these methods the steps (2008 and 2029, respectively) of “optically measure monitored sites of good” would translate to “optically measure monitored sensor-indicator sites of good”.
As previously mentioned the indicator-sensor may be passive (e.g. not requiring any additional power, or access to processing capability) or active (e.g., requiring a power source dedicated, or shared with the optical state monitor or components thereof, e.g., processors). Configurations with dedicated (separate) power sources and processors may in particular be advantageous wherein the indicator-sensor is not directly coupled to the optical state monitor (e.g. on opposite side of the good as shown in Example B below). The power source (in addition to those mentioned above) may also include a mechanical energy harvester.
Certain indicator-sensors may in addition to their property of changing their optical state (optical profile) in response to a stimulus (a change in the good or environment) also may inherently, or with the addition of a suitable additive, change one or more of their electrical properties in ways that are correlated with the change in its optical state (e.g. chemochromic indicator-sensors that also change their electric or ionic conductivity, or amperometric biosensors incorporating electrochromic layers). The electrical signal (e.g. a voltage, current, or impedance level) may be detected and measured across a set of (optionally dedicated) sensing electrodes by the optical state monitor. Other indicator-sensors may provide a change in a secondary property (correlated with the change in the optical state) that may be converted to an electrical output signal via a transducer (e.g. a cholesteric liquid crystal force indicator-sensor also including a piezo sensor).
In either of the preceding cases, electrical output signals correlated to the optical profile of the indicator-sensor may favorably be utilized to verify the optical state of the sensor-indicator as measured and determined by the optical state monitor thereby improving system integrity and reliability) using electrical verification systems and methods such as those described above. Optionally, the determined optical state or verified state (using electrical or optical verification systems and methods such as those described herein) of the indicator-sensor may further trigger another action, e.g.: a further measurement (e.g. with a different type of indicator-sensor or ‘traditional’ (i.e. without an indicator-sensor) optical state monitor of the good); activation of light exposure (e.g. UV light for self-disinfection) of good (or surface) using an integrated or dedicated light layer; communication (e.g. wirelessly) to an external device/system (e.g. to sterilize good by ionized radiation); or activation of a beacon (e.g. visible or audible warning/alert signal).
As described above, there are many possible configurations and combinations of optical state monitors augmented with an indicator-sensor. An optical state monitor may for example be configured to operate a discrete indicator-sensor with a single or a multitude of light (electromagnetic radiation) detectors (or layers), but may also be configured to operate and support a plurality of discrete indicator-sensors with one or many light detectors. Such configurations may further have a single or multiple light (electromagnetic radiation) sources (or light source layers), that are shared (favorably) or not for the light detection (i.e., the light-sensor may have a dedicated light source). Below are several exemplary configurations (Examples A-E) of an optical state monitor augmented by an indicator-sensor. For simplicity and clarity, illustrated (in Examples A-D) are exemplary embodiments that only comprise a single indicator-sensor, a single light detection layer, and a single light source layer (in addition to available ambient light where applicable), at a single monitor site/location (i.e. a single segment or pixel) of a good. Example E is an exemplary embodiment comprising a plurality optical state monitors each augmented by an indicator sensor. For each of the exemplary embodiments only key layers and interfaces are illustrated to disclose the novel aspects of each configuration, i.e., for example environmental barrier layers, light shielding layers, focusing layers, microfluidic channel structure layers, other structures, index matching layers, AR coatings, optical filters, adhesive layers, container walls (of good), removable protective layer or membrane of indicator-sensor, electrode layers (e.g. for light detector layer or electrical verification of indicator-sensor), cladding layers (TIR waveguide), processor, power source, connections, or other optional components, etc. are not shown.

EXAMPLE A

FIG. 54 shows an exemplary embodiment 2100 (in side view, not to scale) of a vertically integrated optical state monitor augmented with an indicator-sensor in reflection mode coupled to a good. In this configuration the optical state monitor (layer) 2101 is integrated or coupled (e.g. with an adhesive layer) to the indicator-sensor (layer) 2102, which further are collectively coupled (e.g. with an adhesive layer) to a good 2103. The optical state monitor further comprises a light detection layer 2104 coupled to an (optional) light source layer 2105. In this particular embodiment the light source layer 2105 is coupled indicator-sensor 2102 but it may also be configured as an inverted stack with the light detection layer 2104 coupled to the indicator-sensor 2102.
The indicator-sensor 2102 comprises a detector interface 2106 facing the optical state monitor (for detection) and a sensor interface 2107 on its opposite side that faces and is proximate the good 2103 (for sensing the good). The detection interface 2106 comprises a reflective surface or layer (or one or more reflective interfaces in a sublayer structure (e.g. interference stack) of the indicator-sensor) that changes (‘self-switches’) the optical state of the detection interface in response to a condition or characteristic of the good 2103 as sensed by the sensor interface 2107. For example the good may be a liquid (e.g. wine) and the measure of the liquid may for example be its level of acidity with the indicator-sensor comprising of a chemochromic type (e.g. pH indicator film/layer). In this case a change in acidity level of the liquid would cause the indicator-sensor to ‘self-switch’ through a chemical reaction and subsequently change its optical state as detectable through its detection interface 2106. Note that the detection interface and the sensor interface may be the same layer (e.g. a chemochromic pH indicator-sensor layer). The detection of the optical-state change or profile is achieved by illuminating the detection interface 2106 by electromagnetic radiation 2120 (e.g. light) originating from the light source layer 2105 (see, e.g. light source layer 76 in FIG. 3B or 176 in FIG. 5 above) and measuring the reflected light 2121 from the (reflective) detection interface 2106 impinging on the light detection layer 2104 (see, e.g. light detection layer 177 in FIG. 5 above). The means and methods for measuring and subsequently determining the condition of the good, is analogous to determining the condition of a good utilizing an optical state monitor discussed above.

EXAMPLE B

FIG. 55 shows an exemplary embodiment 2200 (in side view, not to scale) of a vertically distinct optical state monitor augmented with an indicator-sensor in reflection mode coupled to a good. In this configuration the optical state monitor (layer) 2101 and indicator-sensor layer 2202 are separately coupled (e.g. with adhesive layers) to and on opposing sides of a good 2203. The optical state monitor 2101 is analogous to that of Example A above; however, the interrogating wavelength(s) of the electro-magnetic radiation is favorable selected in a region of the spectrum wherein the good 2203 is substantially transparent. In this particular embodiment the indicator-sensor 2202 is configured with sensor interface 2207 laterally displaced from the detection interface 2206. It should be noted that the sensor interface may also be superimposed and positioned behind (i.e. below in FIG. 55) the detector interface. In this case it is also desirable that the sensor interface (and associated reflective stack) is substantially transparent at the interrogating wavelength(s). Optionally, and in particular wherein the thickness of the good 2203 is significant, a focusing layer (e.g. a micro lens array) may added (e.g. between the light layer 2105 and the good 2203. This particular embodiment may advantageously be combined (e.g. in a segmented or pixelated configuration) with a ‘traditional’ optical state monitor also operating at a different wavelength range wherein the good is reflective (or absorptive in conjunction with e.g. a mirror on the opposite side of the good).

EXAMPLE C

FIG. 56 shows an exemplary embodiment 2300 (in side view, not to scale) of a laterally integrated optical state monitor augmented with an indicator-sensor in total internal reflection (TIR) mode coupled to a good. In this configuration the optical state monitor (layer) 2301 comprising a light detection layer 2304 receives its reflected light 2321 for detection via a light waveguide (or light guide) 2330 (e.g. plate or fiber) of the indicator-sensor 2302. The indicator-sensor 2302 also comprises a light source 2309, here shown as an edge coupled LED or LD to the light guide 2330, which also comprises a combined detection/sensor interface 2310. In this configuration light from the light source 2309 is guided through total internal reflection (TIR) by the light guide 2330 to detection/sensor interface 2310 wherein the light (e.g. evanescent waves) senses a characteristic of the good 2103 of interest (e.g. particular molecule or species). The detection/sensing interface 2310 may comprise a detection film layer (e.g. of deposited metal, e.g. gold, not shown in FIG. 56) to detect certain species via surface plasmon resonance (SPR). Subsequently, the reflected light from the detection/sensing interface 2310 is further guided to an outcoupling region 2311 of the light guide 2330 where the (outcoupled) light 2321 is redirected and outcoupled to the light detection layer 2304. Optionally, and in particular wherein the detection/sensor interface 2310 (or optionally detection film layer) is sensitive to contamination, a removable cover layer or film may be applied prior to coming in contact with the good. In case of a liquid good and wherein the good may alternatively be contained in a microfluidic channel(s), a removable seal may also be applied prior to filling the channel with the liquid good to protect the detection interface/film.

EXAMPLE D

FIG. 57 shows an exemplary embodiment 2400 (in side view, not to scale) of a vertically integrated optical state monitor augmented with an indicator-sensor coupled to a good for detection of an environmental condition (or stimulus). Note that for this embodiment 2400 the (vertical) stack is inverted as compared to that of embodiment 2100 in FIG. 54. In other words the optical monitor is configured in-between the indicator-sensor 2402 and the good 2103. Accordingly, the sensor interface 2107 may be exposed to (and the indicator-sensor react to) environmental stimuli 2409 (e.g. temperature, moisture, UV light, etc.), whereas analogously the optical state (profile) of the detection interface 2106 is detected by the light detection layer 2104 in reflection mode using the emitted light 2120 of the light source layer 2105 of the optical state monitor 2401. Alternatively, ambient light 2412 may be used as a light source (instead of the light source layer 2105) as a detection means of the optical state (profile) of the indicator-sensor (in transmission mode). However, in this case the indicator-sensor and the light source layer 2105 (if present) are advantageously transparent at the ambient light source wavelength of interest. Furthermore, note that for this particular embodiment the optical state monitor may further be advantageously segmented or pixelated with a bidirectional light source layer (e.g. an OLED layer) and appropriate light masking layers to determine the utility of the good based on both the environmental conditions (using a segment configured per above) and conditions of the good itself (using a segment detecting the good).

EXAMPLE E

FIG. 58 shows an exemplary embodiment 2500 (in side view, not to scale) of two segments (Segment 1 and Segment 2) each comprising a vertically integrated optical state monitor augmented with an indicator-sensor for detection of an environmental condition (or stimulus) in reflection mode (with layers equivalent to that of stack in embodiment 2400 with an indicator-sensor layer 2402 and an optical state monitor layer 2401). Each segment stack may advantageously be tailored to the specific environmental condition to be detection (e.g. moisture and UV light). Each segment stack may also favorably be fabricated in-situ (e.g. with additive or subtractive processes) directly on a common substrate 2530, or on carrier substrates (e.g. each segment type using a separate process and carrier substrate) and subsequently transferred and assembled (e.g. via an adhesive, not shown) onto the common substrate 2530.
While particular preferred and alternative embodiments of the present intention have been disclosed, it will be appreciated that many various modifications and extensions of the above described technology may be implemented using the teaching of this invention. All such modifications and extensions are intended to be included within the true spirit and scope of the appended claims.

Claims

What is claimed is:

1. An optical state monitor constructed to determine a state of an item or an environment, comprising:

one or more electromagnetic indicator-sensors for generating an optical signature responsive to the good or the environment;

one or more electromagnetic detectors for detecting electromagnetic radiation from the indicator-sensors, wherein the detected electromagnetic radiation is dependent on the generated optical signature,

a memory constructed to store a predefined optical state profile regarding the state of the item or environment;

a processor for evaluating the generated electronic signals using the optical state profile to determine the state of the item or the environment;

a power source; and

wherein the electromagnetic detectors are constructed to detect electromagnetic radiation corresponding to the optical state profile.

2. The optical state monitor of claim 1, wherein the indicator-sensors are the same type.

3. The optical state monitor of claim 1, wherein the indicator-sensors are of different types.

4. The optical state monitor of claim 1, wherein the electromagnetic radiation detectors are the same type.

5. The optical state monitor of claim 1, wherein the electromagnetic radiation detectors are of different types.

6. The optical state monitor of claim 1, further comprising electromagnetic radiation detectors configured to detect electromagnetic radiation directly from the item or the environment.

7. The optical state monitor of claim 1, further comprising one or more electromagnetic radiation sources.

8. The optical state monitor of claim 7, wherein the electromagnetic sources produce electromagnetic radiation of different types.

9. The optical state monitor of claim 1, wherein the indicator-sensors are integral to the optical state monitor.

10. The optical state monitor of claim 1, wherein the indicator-sensors is attachable, detachable, connectable, disposable, swappable, or replaceable.

11. The optical state monitor according to claim 1, wherein the optical signature detection is performed according to an optical measurement protocol stored in memory.

12. The optical state monitor of claim 10, further comprising an environmental sensor, and responsive to an electrical signal from the environmental sensor, the processor adjusts the optical measurement protocol.

13. The optical state monitor of claim 1, further comprising a visual or acoustic interface for presenting alerts, alarms, or messages.

14. The optical state monitor of claim 1, further comprising a wired or wireless interface for presenting alerts, alarms, or messages.

15. The optical state monitor of claim 1, further comprising an actuator.

16. The optical state monitor of claim 14, wherein the actuator is the light detection layer, and responsive to light stimulation, the light detection layer causes the optical state monitor to transition from a zero or low power state to a higher power state.

17. The optical state monitor of claim 1, wherein the determined optical state of the item or environment is indicative of a condition, characteristic, quality, utility of the item or its environment.

18. The optical state monitor of claim 1, wherein the indicator-sensors or the electromagnetic radiation detectors are constructed as a layer.

19. The optical state monitor of claim 7, wherein the electromagnetic radiation sources are constructed as a layer.

20. The optical state monitor of claim 1, wherein one or more indicator-sensors are visible to a user.

21. The optical state monitor of claim 1, having a plurality of indicator-sensors that are spaced apart from each other.