Writing instrument

Abstract

1. A writing instrument (10) configured to emit light to change the appearance of a substrate (52) including at least one photochromic material, the writing instrument (10) comprising: an elongated body portion (12) that allows a user to grip the writing instrument, the body portion including a proximal end (P) and a distal end (D); a first light source (16) configured to emit light from the proximal end, the emitted light including at least a first color component within a first wavelength range (65), the first wavelength range corresponding at least in part to a deactivation spectrum of a first photochromic material (62Y) of the substrate (52); and a controller (18) configured to receive input from a user and generate a signal to control the first light source based on the received user input.

Description

[Technical field]

[0001] This application claims the benefit of European Patent Application EP21196016.6, filed September 10, 2021, the contents of which are incorporated herein by reference.Embodiments described in the following disclosure relate to writing instruments configured to emit light for altering the appearance of a substrate comprising at least one photochromic material, as well as related methods, photochromic writing systems, computer program elements, and computer readable media. [Background technology]

[0002] Methods of writing or drawing on the material include writing on paper with a pen and permanent ink, writing on paper with a pencil, or writing on a whiteboard surface with non-permanent ink, such as a BIC Velleda™ whiteboard.

[0003] Erasability, or the ability to remove ink from a surface after the ink formulation has been applied and dried, is a challenge in the stationery category. The majority of available solutions focus on single-color writing products. Changing the color of the writing surface typically requires rewriting with a different ink color, which slows the user down and does not allow for resetting. Furthermore, using incompatible inks to change the color of a surface can result in peeling, blistering, or color blending of two or more colors.

[0004] Modern consumers are typically becoming more interested in personalized writing products with added features. Such products can be personalized to suit the needs of individual users. Furthermore, as environmental concerns continue to grow, writing options that allow for reuse of the writing medium may become increasingly important.

[0005] Thus, a writing device may be provided that provides greater flexibility for the user and improved environmental outcomes. Summary of the Invention

[0006] According to a first aspect, there is provided a writing instrument configured to emit light to change the appearance of a substrate including at least one photochromic material, the writing instrument comprising an elongated body portion that allows a user to grip the writing instrument, the body portion comprising a proximal end and a distal end.

[0007] The writing instrument further comprises a first light source configured to emit light from the proximal end, the emitted light including at least a first color component within a first wavelength range.

[0008] The writing instrument further comprises a controller configured to receive input from a user and generate a signal to control the first light source based on the received user input.

[0009] The writing instrument further comprises a user-actuatable color selector configured to receive color setting commands from a user of the writing instrument and to provide the color setting commands to the controller.

[0010] According to this aspect, a luminous writing instrument is provided that can provide a non-permanent marker that can mark using at least one color. A user can use a single luminous writing instrument to write or draw in one or more colors on a photochromic surface substrate without depositing any ink, creating graphite marks, or requiring re-inking. This is possible because the writing medium including the substrate is covered with at least one substance that changes its color based on the intensity and wavelength of light to which the substrate is exposed. The luminous writing instrument can emit one or more colors of light from its tip at various intensities that correspondingly change the color of the light-activated photochromic material on the writing medium.

[0011] The combination of a light source capable of emitting a wide range of colors, or a single light source, combined with a combination of photochromic materials on a writing medium substrate, allows a wide gamut of color space to be displayed to the writer. In an example, a writing system may include a single photochromic material and a stylus configured to emit a single color spectrum. In this case, a similar system may be provided that performs the artistic function of a monochromatic ink pen.

[0012] Photochromic materials are typically resettable (erasable) by irradiating a portion of the substrate with radiation of a particular wavelength range, specifically UV. Such portions appear opaque when that particular wavelength of radiation (e.g., UV) is irradiated onto the substrate. This process is referred to as activating at least one photochromic material.

[0013] Light-based actuation of the photochromic medium means that the effective tip size of the stylus can be changed by varying the focal characteristics of at least one light source of the stylus.

[0014] According to a second aspect, there is provided a method for using a writing instrument configured to emit light to change the appearance of a substrate comprising at least one photochromic material, the method comprising: receiving a color setting command from a user of the writing instrument from a user-actuatable color selector of the writing instrument; providing color setting commands to a controller of the writing instrument; Calculating a setting required for at least a first color component emitted by a first light source of the writing instrument; controlling a first light source to emit light including at least a calculated first color component, the first color component being within a first wavelength range that corresponds at least in part to a deactivation spectrum of a first photochromic material of a substrate of the proximity writing medium; A method is provided that includes positioning a proximal end of a writing instrument relative to a proximate writing medium such that a substrate of the proximate writing medium, the substrate including at least a first photochromic material, is exposed to light generated by a first light source.

[0015] According to a third aspect, There is provided a photochromic writing system comprising a writing instrument according to the first aspect or an embodiment thereof and a writing medium 50 (surface) comprising a substrate treated with a photochromic material. The writing instrument is configured, in use, to emit light in the visible spectrum capable of deactivating the photochromic material contained in the substrate of the writing medium, thereby altering the appearance of a portion of the writing medium.

[0016] According to a fourth aspect, there is provided a computer program element comprising machine executable instructions which, when executed on a computer processor, cause the processor to perform steps according to the method of the second aspect.

[0017] According to a fifth aspect, there is provided a computer readable medium comprising a computer program element of the fourth aspect.

[0018] In this specification and claims, the term "proximal end" refers to the end of the stylus that is held closest to the writing medium when in use, as compared to the "distal end" of the stylus. If the stylus includes a first light source for writing on a substrate and a second light source at an opposite end of the stylus for erasing the substrate, the convention herein is that the proximal end of the stylus is the end of the stylus with the first light source for writing on the substrate.

[0019] In this specification and claims, the term "photochromic material" (or "photochromic dye") refers to a material that utilizes photochromism. Photochromism is the reversible transformation of a chemical species between two forms mediated by the absorption of electromagnetic radiation. Typically, the two forms of a chemical species have different absorption spectra. To an observer, the resulting material can have the effect of providing a reversible change in color when exposed to light. Photochromic materials can include photochromic dyes (paints or inks), photochromic films, or photochromic plastics. In other words, photochromic materials are light-activated materials. To enable the photochromic material to be applied to a surface, the photochromic material can be mixed with an encapsulant, such as, for example, a lacquer or a resin.

[0020] As used herein, the term "writing instrument" refers to a stylus that contains a light source at its proximal end that can be held by a user to produce a visible marking on a substrate of a writing medium that contains, for example, at least one photochromic dye. [Brief description of the drawings]

[0021] Other features will become apparent from the accompanying drawings, which form a part of this disclosure. The drawings are intended to further explain the disclosure and to enable those skilled in the art to practice the disclosure. However, the drawings are intended as non-limiting examples. Common reference numbers in different figures indicate similar or similar features. [Figure 1] 1 shows a plot illustrating the activation and deactivation spectra of three photochromic materials. [Diagram 2] 1 shows a plot showing three light source spectra overlaid on the activation and deactivation spectra of three photochromic materials. [Figure 3a] 1 shows diagrammatically a writing instrument according to a first embodiment and a photochromic writing system according to a third embodiment; [Figure 3b] 1 shows diagrammatically the functional relationships of the elements of a writing instrument according to a first embodiment; [Figure 4] 4 illustrates generally an example of a computer-executable algorithm for setting the intensity of a light source. [Diagram 5] 2 illustrates diagrammatically a method according to a second embodiment; [Figure 6] 1 illustrates an exemplary method. [Figure 7] 1 shows a schematic diagram of a writing instrument for writing on a photochromic writing system. [Figure 8] 1 shows a schematic of a writing instrument being used to erase writing applied to a photochromic writing system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Current writing devices have relatively long ink drying times on some media, leaving behind text and graphic marks that easily smudge. Mixing multiple ink colors in a wet state to obtain a unique color can result in unattractive bleeding and uneven ink mixing. Conventional writing devices often have a fixed nib size, and if a user wants to use a variety of nib sizes, the user must purchase and store a variety of different pens. It is becoming increasingly important to reduce the amount of paper waste and to reduce the number of plastic and non-reusable products.

[0023] Photochromic materials can be converted from a transparent state to a colored state via absorption of ultraviolet (UV) light. Application of UV light to a photochromic material places the photochromic material in a so-called "activated" state, causing the photochromic material to display color. By absorbing visible light of a deactivating wavelength, the photochromic material is converted from a state displaying color to a substantially transparent state (a so-called "deactivated state"). Each photochromic material (pigment) has a different activation spectrum, and light applied to a portion of the photochromic material that falls within the activation spectrum activates a portion of the photochromic pigment, making it opaque. This is more pronounced, or faster, the closer the wavelength of the incident light is to the peak of the activation spectrum for a given photochromic material.

[0024] It is possible to use a single photochromic material in a monochromatic photochromic writing medium solution, however, to allow obtaining a more complex color space for the wavelength of incident light, for example, two or more photochromic materials can be mixed together and separated in a translucent resin or other transparent material.

[0025] FIG. 1 shows a plot illustrating the activation and deactivation spectra of three photochromic materials.

[0026] The paper "ColorMod: Recoloring 3D Printed Objects using Photochromic Inks" by Punpongsanon et al., CHI 2018, April 21-26, 2018, Montreal, QC, Canada (ISBN 978-1-4503-5620-6 / 18 / 04) describes photochromic inks, as well as activation and deactivation spectra for three photochromic materials. The paper "Photo-Chromeleon: Re-Programmable Multi-Color Textures Using Photochromic Dyes" by Jin, Y et al., UIST'19, October 20-23, 2019, New Orleans, LA, USA (ISBN N 978-1-4503-6816-2 / 19 / 10) describes different arrangements of dyes.

[0027] Figure 1 was taken from a chart available from Yamada Chemical Industry Co., Ltd., Kyoto, Japan (http: / / ymdchem.com) and described in the above-mentioned paper. For example, Figure 1 shows the activation and deactivation spectra of DAE-0001 (blue), DAE-0004 (red), and DAE-0068 (yellow), available from Yamada Chemical Industry Co., Ltd.

[0028] In Figure 1, the x-axis represents the wavelength of incident electromagnetic radiation used to activate or deactivate the photochromic material, and the y-axis represents the normalized absorption of a given photochromic material at that wavelength.

[0029] Specifically, dotted line 62Y is the inactivation spectrum of yellow photochromic material DAE-0068 (hereinafter "yellow"), dotted line 62R is the inactivation spectrum of red photochromic material DAE-0004 (hereinafter "red"), dotted line 62B is the inactivation spectrum of blue photochromic material DAE-0001 (hereinafter "blue"), solid line 64B is the peak of the activation spectrum of the blue photochromic material, solid line 64R is the peak of the activation spectrum of the red photochromic material, and solid line 64Y is the peak of the activation spectrum of the yellow photochromic material.

[0030] Boundary 63 indicates the approximate transition between ultraviolet (UV) and visible light wavelengths. Thus, DAE-0001 (blue) has an activation peak at about 270 nm and a deactivation peak at about 580 nm, DAE-0004 (red) has an activation peak at about 310 nm and a deactivation peak at about 225 nm, and DAE-0068 (yellow) has an activation peak at about 350 nm and a deactivation peak at about 425 nm. The combination of the three identified photochromic dyes in FIG. 1 provides an RGB color space, but is for illustrative purposes and is not required. For example, two or one photochromic material can be utilized. More than three photochromic materials can be utilized.

[0031] For example, another exemplary color combination is Yamada DAE-0001 (blue), DAE-0012 (magenta), and DAE-0068 (yellow) to obtain a CMY color space. DAE-0012 has a deactivation peak at 530 nm. When all components of the CMY photochromic material mixture are activated, a black writing medium surface is obtained.

[0032] FIG. 2 shows a plot showing three light source spectra for deactivating the blue, green and red photochromic materials, respectively, superimposed on the activation and deactivation spectra of the three photochromic materials in the first example combination of DAE-0001, DAE-0004 and DAE-0068. The "I" axis on the right side of the plot is an exemplary scale of the normalized intensity of the blue, green or red light source, respectively. The red light source spectrum has a spectral peak 66R at about 620 nm. The green light source spectrum has a spectral peak 66G at about 525 nm. The blue light source spectrum has a spectral peak 66B at about 440 nm.

[0033] These wavelength ranges are exemplary and other light sources having different wavelengths and / or different spectral linewidths may be used to deactivate the red, blue, or yellow photochromic materials in the example of FIG. 1. Deactivation is most effective and more rapid when the peak deactivation wavelength of a given light source coincides with the deactivation peak of the corresponding dye. The linewidths of each of the blue 66B, green 66G, and red 66R light sources are shown by wavelength ranges 65, 67, and 69, respectively. For example, wavelength ranges 65, 67, and 69 may be defined by the 3 dB drop points of the respective linewidths.

[0034] Depending on the photochromic material combination used, the light source linewidth can be selected to maximize inactivation of the target dye while affecting adjacent dye inactivation spectra as little as possible. However, the light source linewidth requirements can be relaxed using several techniques. For example, the light source may be applied to the substrate 52 in a rapidly repetitive time sequence designed to minimize leakage between color channels. The color space can be limited to color options that do not cause spectral mixing between the available photochromic materials and light sources.

[0035] Colored photochromic pigments of base colors (e.g., CMY) can be mixed together and isolated in a resin or lacquer. This provides a photochromic paint formulation for application to a writing medium (e.g., a whiteboard or handheld tablet) (although in the basic option, only one photochromic material needs to be used). In one example with two or more photochromic materials, the paint formulation has the ability to change color on demand by individually deactivating each photochromic material.

[0036] In one example using the CMY color space (e.g., via a paint formulation including DAE-0001, DAE-0004, and DAE-0068), the paint formulation is first activated (by exposure to UV light). As a result, the colors are all fully saturated (in the example CMY color selection, the paint formulation appears black). If the user wishes to paint in yellow, the C and M dyes should be deactivated. Deactivation could be accomplished in this example by exposing the paint formulation to 580 nm (cyan) and 530 nm (magenta) light for a predetermined period of time. Once the C and M dyes are deactivated, the paint formulation appears yellow.

[0037] The paint formulation can be reset by exposure to UV light having a wavelength of, for example, 365 nm, which resaturates all of the pigments. In one example, this reset process involves exposing the paint formulation to UV light having a power of, for example, about 5 mW per square centimeter for 30 seconds. For example, power-efficient UV Light Emitting Diodes (LEDs) that can emit light at a wavelength of 365 nm are available, as well as LEDs that can emit RGB colors.

[0038] According to a first aspect, a writing instrument 10 is provided that is configured to emit light to change the appearance of a substrate 52 that includes at least one photochromic material. The writing instrument comprises an elongated body portion 12 that allows a user to grip the writing instrument, the body portion comprising a proximal end P and a distal end D. The writing instrument further comprises a first light source 16 configured to emit light from the proximal end, the emitted light comprising at least a first color component within a first wavelength range 65. The first wavelength range corresponds at least in part to a deactivation spectrum of a first photochromic material 62Y of the substrate (52). The writing instrument also comprises a controller 18 configured to receive input from a user and generate a signal to control the first light source based on the received user input.

[0039] FIG. 3a shows diagrammatically a writing instrument 10 according to a first embodiment and a photochromic writing system according to a third embodiment.

[0040] For example, the writing instrument 10 (or light pen, or light-emitting stylus) of FIG. 3a is an elongated object that can be held, for example, in the hand of an adult or a child. The writing instrument 10 has a proximal end P suitable for orientation to the writing medium 50 during deactivation, and a distal end D. In examples, the writing instrument 10 has a circular, oval, square, rectangular, pentagonal, hexagonal, or heptagonal cross-section, at least along a segment. Although the writing instrument 10 is shown as an elongated object aligned, for example, along a longitudinal axis L, this is not required. For example, the writing instrument 10 may comprise a flexible segment (not shown) that can be realigned from the longitudinal axis L, for example, with light from the first light source 16 being transmitted via an optical fiber along a portion of the writing instrument.

[0041] The form factor of elongated body 12 may vary along longitudinal axis L of writing instrument 10 (not shown), for example, to accommodate ergonomic variations or to enhance user comfort. In the illustrated example, writing instrument 10 includes body portion 12a, tapered body portion 12b, and optical nib portion 12c.

[0042] For purposes of describing writing instrument 10, writing medium 50 (with which the writing instrument is intended to be used) can be considered to be, for example, a substantially planar, rigid backing layer 54 on which is provided a photochromic substrate layer 52. Photochromic substrate layer 52 can include one or more photochromic materials (pigments) selected to provide a color space of interest. It is not necessary for writing medium 50 to be substantially planar, and the writing medium can also be a physical object such as a carton, a 3D printed object, a laptop casing, a whiteboard, or many other objects.

[0043] For example, the photochromic substrate layer 52 may include a mixture of Yamada DAE-0001 (blue), DAE-0012 (magenta), and DAE-0068 (yellow) to obtain a CMY color space. In another example, the photochromic substrate layer 52 includes a mixture of Yamada DAE-0001 (blue), DAE-0004 (red), and DAE-0068 (yellow) available from Yamada Chemical Industry Co., Ltd. Those skilled in the art will appreciate that a wide range of photochromic materials may be applied depending on the intended final color specifications.

[0044] In an example, one photochromic material may be applied to the substrate 52. In one example, the one or more photochromic pigments are mixed into a composition that includes a curable lacquer, allowing the one or more photochromic pigments to be permanently applied to the substrate 52.

[0045] Although not required, the writing medium 50 may include an electronic subsystem 56 including a second modem and memory. As described, the electronic subsystem allows the writing instrument 10 to obtain color space data from the writing medium 50 (such as the type of photochromic material used in a given writing medium 50). In an example, the writing instrument 10 may carry a look-up table of target writing media 50, with the identifier of the writing medium being selectable via control of the writing instrument 10 or a smartphone application. This allows the writing medium 50 to be simplified, for example, not requiring a second modem and memory.

[0046] In one example, the overall length of writing instrument 10 in the longitudinal direction L is between 50 mm and 200 mm, specifically 140 mm. In one example, when writing instrument 10 has a circular cross-section, the maximum diameter of the writing instrument is within a range of between 6 mm and 20 mm, specifically 9 mm. The elongated body of writing instrument 10 may comprise, for example, injection molded from polystyrene or polypropylene.

[0047] In the illustrated example, the exterior surface of the writing instrument 10 includes a clip 40 near its distal end to facilitate attachment to, for example, a user's pocket. Near its proximal end, the writing instrument 10 includes a user grip 30 made of a resilient material, such as rubber. The user grip 30 can be shaped to achieve an ergonomic fit with a typical user profile to improve writing comfort.

[0048] The elongated body portion 12 of the illustrated writing instrument 10 encloses a first light source 16 (a deactivation light source for at least one photochromic material), a focusing element 32, and an optical coupler 14 having a protruding optical nib portion 42. The first light source 16 is configured to generate a deactivation light for deactivating the photochromic pigment. In the illustrated example, the aforementioned elements are aligned along a longitudinal axis L, such that the deactivation light is transmitted from the first light source 16 through the focusing element 32 and the optical coupler 14 and out of the protruding optical nib portion 42, such that the separate photochromic substrate layers 52 of the separate writing media 50 are deactivated using light having one or more wavelengths provided by the first light source 16. In another example, the first light source need not be aligned with other elements in the elongated body 12 along the longitudinal axis L. The light emission from the first light source 16 may be distributed using, for example, a light pipe or optical fiber.

[0049] The user-actuatable color selector is configured to receive color setting commands from a user of the writing instrument 10 and to provide the color setting commands to the controller.

[0050] Writing instrument 10 includes a color selector 20 and a beam size selector 22, which will be described in more detail below. Color selector 20 and beam size selector 22 are accessible, for example, on an exterior surface of elongated body portion 12. Color selector 20 and beam size selector 22 are configured to provide input signals to controller 18. Controller 18, first light source 16, and focusing element 32 receive electrical energy from power source 26.

[0051] In one embodiment, the controller 18 is configured to perform one or more of the following functions: performing color setting calculations for the first light source 16, driving a display of the color selection system, controlling the first and / or second light emitting sources, accepting input from the beam size selector 22 and controlling the focusing element 32 accordingly, and monitoring and controlling the power supply 26 and / or the first modem 28. The controller may be, for example, a microprocessor or microcontroller.

[0052] FIG. 3b shows diagrammatically the functional relationships of the elements of a writing instrument 10 according to a first embodiment.

[0053] In one embodiment, color selector 20 includes a fixed selection of preset buttons for selecting available color options. In one embodiment, color selector 20 may be a rotating wheel or sliding selector on elongated body portion 12, allowing selection of a predetermined color by moving the selector a predetermined displacement.

[0054] In one example, writing instrument 10 may include a display (not shown) connected to controller 18. The display may be configured to indicate selected or available color and / or nib size settings to a user. In one example, the display may include, for example, a single color LCD, a color OLED, a multi-color LED, or a thin film transistor display. In an example, the display may be a number of stand-alone LEDs displayed around or along elongated body 12, for example, to indicate separate color options.

[0055] In one example, power source 26 may be a rechargeable "AA" battery or one of many alternatives. The power source may include, for example, a wired or wireless charging system.

[0056] The writing instrument 10 may, in one example, include a second light source 24 (capable of activating at least one photochromic dye). The writing instrument 10 may, in one example, include a third light source 24 (capable of activating at least one photochromic dye). In the illustrated example, the second light source is provided at a distal end D of the writing instrument 10, intuitively replacing a conventional pencil eraser. The second light source 24 may be an ultraviolet light source capable of activating at least one photochromic material. Specifically, the second light source 26 may be configured to emit light having a spectral peak of 365 nm.

[0057] Writing instrument 10 may include a camera 38 for providing feedback to controller 18 of the color of substrate 52 obtained during operation of writing instrument 10 in combination with a particular combination of photochromic materials, an embodiment of which is described below.

[0058] The writing instrument 10 may include a first modem 28 capable of transmitting data from the controller 18 to another modem, and receiving data from the other modem 18 and providing it to the controller 18. Applications for providing the writing instrument 10 with data connectivity are described below.

[0059] In operation, a user obtains a writing medium 50 including a substrate 52 containing at least one photochromic material. In a normal starting condition, the at least one photochromic material included in the substrate 52 is substantially or fully activated, such that the substrate appears saturated to the user. In an example where the substrate 52 includes a mixture of CMY photochromic materials, the substrate 52 appears substantially black. The user turns on the stylus 10 and selects a color and / or intensity via the color selector 20. The controller 18 receives a color and / or intensity input signal provided by the color selector 20. A look-up table or algorithm is used to calculate the intensity of at least one component light source included in the first light source 16. The at least one component light source of the first light source 16 is then activated at the intensity calculated or obtained by the controller 18.

[0060] In one example, the user can select the beam size using the beam size selector 22 (operably coupled to the focusing element 32). The user then holds the stylus 10 so that the proximal end P of the stylus 10 is close enough to the substrate 52 of the writing medium 50 to deactivate at least one photochromic material contained in the substrate 52. The user can draw a simple or complex pattern or write desired information on the substrate 52. In one example, the user can adjust one or more of the color and / or intensity via the color selector 20 and / or the beam size using the beam size selector 22. After the writing or drawing session using the writing medium 50 is completed, the user can erase what was written on the substrate 52, for example, using ultraviolet light to activate the trace provided on the substrate 52.

[0061] According to one embodiment, the first light source 16 of the writing instrument is further configured to emit light including a second color component within a second wavelength range 67, which second wavelength range corresponds at least in part to a deactivation spectrum of the second photochromic material 62R of the substrate 52, and the first and second color components can be emitted from the first light source (i) individually, (ii) simultaneously, or (iii) in a predetermined alternating sequence.

[0062] The first color component is defined by light radiation having a first wavelength range having a spectral maximum within one of the following ranges: 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, or 625 nm to 700 nm.

[0063] According to one embodiment, the second color component is defined by light radiation having a second wavelength range having a spectral maximum within one of the ranges 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, or 625 nm to 700 nm.

[0064] In the example, the first wavelength range is 400 nm to 425 nm, and the second wavelength range is 425 nm to 475 nm. The first wavelength range is 400 nm to 425 nm, and the second wavelength range is 475 nm to 525 nm. The first wavelength range is 400 nm to 425 nm, and the second wavelength range is 525 nm to 560 nm. The first wavelength range is 400 nm to 425 nm, and the second wavelength range is 560 nm to 590 nm. The first wavelength range is 400 nm to 425 nm, and the second wavelength range is 590 nm to 625 nm. The first wavelength range is 400 nm to 425 nm, and the second wavelength range is 625 nm to 700 nm.

[0065] In an example, the first wavelength range is 425 nm to 475 nm and the second wavelength range is 475 nm to 525 nm. The first wavelength range is 425 nm to 475 nm and the second wavelength range is 525 nm to 560 nm. The first wavelength range is 425 nm to 475 nm and the second wavelength range is 590 nm to 625 nm. The first wavelength range is 425 nm to 475 nm and the second wavelength range is 526 nm to 700 nm.

[0066] In an example, the first wavelength range is 475 nm to 525 nm and the second wavelength range is 525 nm to 560 nm. The first wavelength range is 475 nm to 525 nm and the second wavelength range is 560 nm to 590 nm. The first wavelength range is 475 nm to 525 nm and the second wavelength range is 590 nm to 625 nm. The first wavelength range is 475 nm to 525 nm and the second wavelength range is 625 nm to 700 nm.

[0067] In an example, the first wavelength range is 525 nm to 560 nm and the second wavelength range is 560 nm to 590 nm. The first wavelength range is 525 nm to 560 nm and the second wavelength range is 590 nm to 625 nm. The first wavelength range is 525 nm to 560 nm and the second wavelength range is 625 nm to 700 nm.

[0068] In an example, the first wavelength range is 560 nm to 590 nm and the second wavelength range is 590 nm to 625 nm. The first wavelength range is 560 nm to 590 nm and the second wavelength range is 625 nm to 700 nm.

[0069] In an example, the first wavelength range is from 590 nm to 625 nm and the second wavelength range is from 625 nm to 700 nm.

[0070] According to one embodiment, the light emitted by the first light source further comprises a third color component having a spectral maximum within a third wavelength range, in an example, the third wavelength range is selected to include a maximum within one of the following ranges: 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, and 625 nm to 700 nm.

[0071] The first light source 16 may, in an example, be configured to output light consisting of one color component within the first wavelength range 65. Such a definition may be appropriate for a substrate 52 that includes one photochromic material.

[0072] According to one embodiment, the first light source 16 is selected from the group of a light emitting diode configured to emit light in at least a first wavelength range, a tunable variable color LED, one or more laser light sources, or one or more multi-color LEDs including corresponding filtering elements in at least the first wavelength range.

[0073] For example, the first light source may include a single multi-color LED configured to emit one, two, or three colors, e.g., RGB. The first light source may include a single multi-color LED configured to emit a range of colors within an adjustable color gamut. The first light source is configured to emit light having a spectral maximum in at least two of the following ranges: 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, and 625 nm to 700 nm. In one example, the first light source may also be configured to generate UV, or specifically, UV-A light, to enable the proximal end of the writing implement to activate details of the substrate 52, thereby acting as a fine eraser.

[0074] According to one embodiment, the controller 18 is configured to receive color setting commands from the user-actuatable color selector 20, calculate required intensity settings of at least a first color component of the first light source that will enable a desired color to be displayed on the substrate 52 that includes at least one photochromic material, and control the first light source 16 to emit light including at least the calculated first color component at the calculated intensity. In one example, the controller 18 is configured to calculate required intensities of the second and / or third color components emitted by the first light source.

[0075] FIG. 4 illustrates generally one example of a computer-executable algorithm, in the form of computer-executable color control instructions 100, for setting the intensity of a light source.

[0076] An exemplary computer-implemented algorithm for controlling the first light source 16 may be executed by the controller 18. In an example, the input color settings 102 may be transmitted via the first modem 28 of the writing instrument 10 to an external processing means, such as, for example, a smartphone running a smart phone or digital tablet application linked to the writing instrument 10. In this case, the external processing means may calculate the color output intensity values ​​and / or sequence information 108 of the first light source and transmit them back to the controller 18 of the writing instrument 10 for implementation on the writing instrument 10. This latter technique is applicable in cases where the controller 18 included in the writing instrument does not have adequate computational resources in view of the required color selection algorithm.

[0077] In one example, the input color setting 102 is received, for example, from the color selector 20 of the writing instrument 10. The color setting calculation 106 includes receiving one of a plurality of quantized selections from a color space, such as the RGB color space. The color setting calculation 106 may include querying a lookup table using the input color setting 102. The lookup table includes pre-calculated values ​​that map the input color setting 102 to output intensity values ​​and / or intensity sequence information 108 of the first light source 16. The controller 18 sets 110 the first light source 16 based on the output intensity values ​​and / or sequence information 108. The first light source 16 emits one or more wavelengths or spectra at one or more appropriate photochromic material deactivation colors to achieve the desired input color setting 102 or a color as close as possible thereto.

[0078] In one example, the input color settings 102 may include one color setting corresponding to a first color desired to be displayed on the substrate 52 of the writing medium 50. In this case, the output intensity value and / or sequence information 108 includes output intensity values ​​and / or sequence information for a first color component within a first wavelength range. This corresponds to a use case with a writing medium 50 having one photochromic pigment, or a use case with a writing medium 50 including multiple photochromic pigments that are intended to be inactivated only by the first color component. In one example, the color components may be considered to be defined by the wavelengths of the spectral maxima of the spectrum of the light source.

[0079] In one example, the input color settings 102 may include two color settings corresponding to a mixture of first and second color coordinates in a limited color space desired to be displayed on the substrate 52 of the writing medium 50. In this case, the output intensity value and / or sequence information 108 includes at least two output intensity values ​​and / or sequence information for a first color component in a first wavelength range and a second color component in a second wavelength range. This corresponds to a use case with a writing medium 50 having two or more photochromic pigments or a use case with a writing medium 50 including multiple photochromic pigments that are intended to be inactivated by the first and second color components.

[0080] In one example, the input color settings 102 may include three or more color settings corresponding to a mixture of first, second, and third color coordinates in a color space (RGB, CMY, etc.) desired to be displayed on the substrate 52 of the writing medium 50. In this case, the output intensity value and / or sequence information 108 includes at least three output intensity values ​​and / or sequence information for a first color component in a first wavelength range, a second color component in a second wavelength range, and a third color component in a third wavelength range. This corresponds to a use case with a writing medium 50 having two or more photochromic pigments, or a use case with a writing medium 50 including multiple photochromic pigments that are intended to be inactivated by at least the first, second, and third color components.

[0081] In one example, the writing medium parameters 104 are provided as part of the color setting calculations 106. For example, a smartphone application configured to perform the color setting calculations 106 and / or a controller 18 configured to perform the color setting calculations 106 may include the writing medium parameters 104.

[0082] In a practical example, the writing medium 50 has an electronic subsystem 56 having, for example, at least a second modem and a memory. The memory stores parameters relating to the photochromic materials contained in the substrate 52 of the writing medium 50, or at least the deactivation spectra of those materials. Thus, the writing instrument 10 and / or a connected smartphone or tablet application can download information detailing the photochromic materials contained within the substrate 52 of the writing medium 50 in a wired or wireless data transmission, such as Bluetooth™, Wi-Fi™, ZigBee™, or NFC communication.

[0083] In an example, a user may identify the type of writing medium being used, and thereby implicitly identify the photochromic material contained in substrate 52 of writing medium 50, by entering a code into a smartphone or tablet application. If color setting calculations 106 have prior knowledge of the photochromic material contained in substrate 52 of writing medium 50, a more accurate set of output intensity values ​​for first light source 16 may be calculated.

[0084] In one example, the input color settings 102 are received via a smart phone or tablet application.

[0085] In one example, the color setting calculation includes calculating a mapping in a color gamut (color space) between the input color settings and the output intensity values ​​and / or sequence information of the first light source 106 .

[0086] In one embodiment, the first light source 16 is configured to emit at least first and second color component outputs polychromatically, i.e. simultaneously, in a steady state.

[0087] In other words, the color setting calculation 106 is responsible for generating the appropriate combination or sequence of light that results in the desired color (selected by the color selector 20) on the substrate 52 of the writing medium 50 using the first light source. The input of the algorithm is, for example, the output of the color selector 20, or a similar implementation thereof in a smartphone or tablet implementation. For example, if a user wants to write in red, the blue and green channels may need to be deactivated from a saturated substrate 52. The output of the color setting calculation 106 is therefore a signal that defines the intensity per color channel. Thus, the R channel may be set to 0% hue, 0% intensity; the G channel will be 100% hue, 100% intensity, and the blue channel will be 100% hue, 100% intensity.

[0088] In another embodiment, the first light source 16 is configured to emit a first color component in a first time interval and emit a second color component in a second time interval that does not overlap with the first time interval.

[0089] In this embodiment, if the first and second photochromic materials are mixed in the same region of the substrate 52, the inactivation of the first photochromic material may also partially inactivate the second photochromic material. Thus, a larger portion of the available color gamut may be achievable if the first color component is applied to the substrate separately from the second color component. For a given combination of photochromic materials, experimentation may allow, for example, an exposure sequence to be generated for a given set of input color settings that achieves acceptable performance within the intended color space. The calculation of whether and how long to expose the first or second color component first may be derived experimentally or may be pre-calculated using an optimization algorithm, such as gradient descent. In one example, the first time interval has a duration in the range of 10 ms to 1 s. In one example, the second time interval has a duration in the range of 10 ms to 1 s.

[0090] In another embodiment, after setting (110) the first light source using the calculated output intensity values ​​or sequence information 118, an element such as a writing instrument 10, a smartphone with a camera (not shown), or another feedback element can observe the color and intensity of the trace as it ultimately appears on the substrate 52 of the writing medium 50.

[0091] 3a, for example, shows an example of using a camera 38 for this purpose. The camera may be a CMOS or CCD camera with appropriate optics provided in a protrusion from the elongated body portion 12 that allows a field of view on the substrate 52. The optical camera 38 allows monitoring 112 of the color of the substrate, thus providing color feedback data. A discrepancy between the intended color output at a given setting of the color selector 20 and the resulting color of the substrate 52 can be detected. The color setting calculation is configured in one embodiment to detect the divergence and recalculate the output intensity values ​​and / or sequence information of the first light source 16 to more accurately represent the intended output color on the substrate 52.

[0092] In one embodiment, the writing medium 50 and associated writing instrument 10 may be configured to undergo a calibration sequence performed by a user. One example of a calibration sequence is for a first light source to be set to emit light having a first wavelength at a known intensity. Via a smartphone application, tablet computer, or PC, the user is instructed to draw a shape on the substrate 52. An image of this shape is captured. The image may be captured, for example, using a camera 38 integral with the writing instrument 10 or by a smartphone camera. The image may be captured to include an image of an associated "color swatch" of a test booklet next to the shape drawn on the substrate 52. The deviation between the lightness and / or hue of the expected image on the substrate 52 and the image on, for example, the "color swatch" or test booklet is used to calculate a correction factor. This calibration process may be repeated, for example, for all primary colors. In an example, the calibration may be performed for any color selection. According to the calibration methods described above, since calibration can be performed from a test swatch or test booklet, the writing medium 50 does not need to include electronics capable of transmitting data defining the photochromic composition of the substrate 52. This allows for more careful matching of different photochromic materials from different photochromic material manufacturers.

[0093] According to one embodiment, an optical coupler is provided between the first light source 16 and the proximal end P of the writing instrument 10. The optical coupler functions to guide the light emitted by the first light source 16 to the proximal end P, where the light is emitted onto the writing medium.

[0094] In one example, the optical coupler 14 is a transparent structure that guides electromagnetic waves in the optical spectrum from the first light source to the proximal end P. The optical coupler 14 may be, for example, an optical fiber or a transparent dielectric waveguide of plastic or glass. The optical coupler 14 may also be a light pipe. The end of the optical coupler 14 located at the proximal end P of the writing instrument may be integrally formed with a static focusing element.

[0095] In one example, the optical coupler 14 and / or the protruding optical tip portion may be omitted such that the transmission path of the light beam from the first light source to the substrate 52 is through free space.

[0096] According to one embodiment, the writing instrument 10 further comprises a focusing element 32 configured to adjust the extent of the illuminated area on the surface of the opposing substrate by adjusting the beam size from the first and / or second light sources.

[0097] FIG. 3 a illustrates diagrammatically an example of a focusing element 32 as comprising a moveable lens, such as a plano-convex lens, in the transmission path of the light beam from the first light source 16 .

[0098] According to one embodiment, the user-actuable beam size selector 22 is capable of receiving beam sizing commands from a user and controlling the focusing elements 32 to provide the beam size selected by the user, the focusing elements 32 being actuated via a mechanical linkage to the beam size selector. In an example, focusing is performed by members that are electronically actuated via the controller 18.

[0099] The focusing element 32 serves to change the effective nib size of the writing instrument 10. The focusing element 32 may comprise, for example, an assembly of one or more movable lenses that accept light from the first light source 16 and manipulate the light to change its focus, effectively changing the nib size. For example, an unfocused light beam may simulate a large nib size (greater than 2 mm, up to 10 mm in diameter). A focused light beam may replicate a fine nib size (e.g., having a diameter of 0.5 mm). The focusing element may be electronically actuated via the beam size selector 22 and the controller 18.

[0100] The plano-convex lens shown in FIG. 3a can be adjusted along the longitudinal axis 52 of the writing instrument 10 using, for example, a rack and pinion mechanism (not shown) or at least one stepper or linear motor controlled by the controller 18.

[0101] The beam size selector 22 is operably coupled to the focusing element 32 and may be, for example, a mechanism capable of adjusting the position of a lens within the focusing element 32 based on a rotational or sliding movement of such a mechanical beam size selector 22 .

[0102] However, other focusing modalities may be applied, for example, focusing element 32 may comprise at least one electrofluidic lens, which contains a focusing liquid and can change its shape, and therefore its focusing properties, based on, for example, an applied electrostatic field.

[0103] In one example, beam size selector 22 is a mechanical selection wheel disposed on elongated body portion 12 of writing instrument 10. For example, the mechanical selection wheel may be mechanically coupled to the lenses of focusing element 32 and configured to directly vary the distance between at least one moveable lens and first light source 16.

[0104] In one example, beam size selector 22 may be a sliding selector having a similar function to a mechanical selection wheel located on the side of elongated body portion 12 of writing instrument 10, coupled to focusing element 32 via a mechanism.

[0105] In one example, the beam size selector 22 may be one or more selection buttons for incrementing through the available nib size options. A single button may be provided on the elongated body portion 12 for cycling through the available nib sizes.

[0106] In one example, the beam size selector 22 may be a menu option on a smartphone application configured to address the controller 18 via the first modem 28.

[0107] Of course, one skilled in the art will appreciate that the final nib size will also depend on situational factors such as how far the substrate 52 is held from the protruding optical nib portion 42 or the proximal end P of the writing instrument 10. To ensure that the nib resizing options are available, appropriate instructions can be provided to the user of the writing instrument. For example, the writing instrument 10 may be provided with instructions stating that the optimal separation between the proximal end P of the writing instrument 10 and the substrate 52 is a given distance, such as 5 mm. In an example, the default separation distance between the proximal end P of the writing instrument 10 and the substrate 52 may be a preconfigurable menu option in, for example, a smartphone configuration application.

[0108] According to one embodiment, the focusing element 32 comprises one or more moveable lenses 34 aligned on the optical axis between the first light source 16 and the optical combiner. In one example, the beam sizing element includes an aperture.

[0109] The aperture comprises a number of flat leaves, each of which intersects with a progressively greater extent of the beam from the first light source 16 as the leaves undergo rotational movement relative to the longitudinal axis of the writing instrument 10, thereby providing another option for controlling the nib size.

[0110] According to one embodiment, writing instrument 10 does not include focusing element 32 and beam size selector 22 .

[0111] According to one embodiment, the writing instrument 10 further comprises a second light source 24 capable of generating a further spectrum of light that at least partially corresponds to the activation spectrum of at least the first and / or second photochromic materials, the second light source generating light having a wavelength in the range of 315-400 nm, or specifically 345 nm.

[0112] Second light source 24 may be considered to be the erasure mechanism of stylus 10. Its inclusion within writing instrument 10 is not essential, as a separate erasure modality using light having a wavelength in the range of 315-400 nm, or specifically 345 nm, may be provided using a separate device, such as a stand-alone erasure wand that emits light having a wavelength in the range of 315-400 nm, or specifically 345 nm.

[0113] In one example, second light source 24 is configured to provide activation light to at least one photochromic material contained on substrate 52, and in one example, to two, three, or more photochromic materials.

[0114] In one example, the second light source 24 is configured to emit ultraviolet or near-ultraviolet light.

[0115] In this embodiment, the second light source 24 may be integral with the writing instrument 10. In one example, the second light source 24 is provided at or substantially adjacent to the distal end of the writing instrument 10 and functions similarly to a conventional pencil-mounted eraser. In one example, the second light source 24 is provided as a substantially linear element along the length of the elongated body portion 12. In one example, the second light source 24 is provided as a substantially linear element that extends over 25% of the total length of the elongated body portion 12. In one example, the second light source 24 is provided as a substantially linear element that extends over 50% of the total length of the elongated body portion 12. In one example, the second light source 24 is provided as a substantially linear element that extends over 75% of the total length of the elongated body portion 12. For example, the substantially linear element may be a leaky light bar or a leaky optical fiber that allows propagation of light from the second light source 24 over a large surface area of ​​the substrate 52 to enable rapid application of activation light from the second light source 24 to a large area of ​​the substrate 52.

[0116] 3a, a second light source 24 is provided as a light source at the distal end D of the elongated body portion 12. In one example, the second light source 24 can be a light switch that is activated and deactivated (toggled) when the switch is pressed and bounced in the direction of the longitudinal axis L of the writing instrument 10.

[0117] According to one embodiment, a second light source 24 is provided at the distal end of the writing instrument 10 .

[0118] In one embodiment, a proximity sensor and / or either an accelerometer included within writing instrument 10 is configured to detect translation of writing instrument 10 between a first state in which first light source 16 is in proximity (optical contact) with substrate 52 and a second state in which second light source 24 is in proximity (optical contact) with substrate 52, or vice versa. When transitioning to the first state, second light source 24 is automatically deactivated by controller 18. When transitioning to the second state, first light source 24 is automatically deactivated by controller 18.

[0119] In another example (not shown), the second light source 24 can be co-located within the elongated body 12 as the first light source 16 and use the same optical transmission path to the substrate 52 as the first light source 16. This can allow, for example, finer erasure precision. In one example, the second light source 24 can be controlled with the color selector 20, for example as a limit or boundary setting of the color selector 20.

[0120] In one example, the second light source 24 generates light at at least one, specifically all, activation wavelengths of the photochromic materials (dyes) used in the substrate 52. In one example, the second light source 24 is configured to generate UV light in the wavelength range of 100-400 nm. In one example, the second light source 24 is configured to generate UV-A light in the wavelength range of 315 nm-400 nm, specifically 345 nm. The second light source 24 can increase or decrease its intensity, for example, based on commands from a controller.

[0121] According to one embodiment, first light source 16 and / or second light source 24 are configured to automatically shut off when not in proximity to substrate 52 .

[0122] For example, the first light source 16 and / or the second light source 24 are equipped with a proximity detector. The controller 18 monitors whether the first light source 16 and / or the second light source 24 meet a proximity criterion to the substrate 52. If the first light source 16 and / or the second light source 24 do not meet the proximity criterion to the substrate 52, this means that the first light source 16 and / or the second light source 24 may be pointing towards the eye of the user or another person. If the proximity criterion is not met, the controller 18 can, for example, deactivate or reduce the intensity of the electromagnetic radiation emitted from the first light source 16 and / or the second light source 24.

[0123] In one example, the proximity detector may comprise a reciprocating or spring-loaded mechanical switch attached to the second light source 24 or, for example, if present, the protruding optical nib portion 42. In one example where the second light source 24 is provided at the distal end of the writing instrument 10, if the distal end of the writing instrument 10 is not in contact with a surface, the mechanical switch is not activated and the controller 18 will not illuminate the second light source 24 for safety reasons. A similar arrangement may be provided for the first light source 16, which is actuable, for example, via a mechanical switch in contact with the protruding optical nib portion 42.

[0124] The proximity detector may be provided, for example, as a photodiode, phototransistor, light dependent resistor, or other electronic actuator capable of sensing the proximity of the first light source 16 and / or the second light source 24 to the substrate 52. The proximity detector may be, for example, a time-of-flight sensor provided at the distal and / or proximal end of the writing instrument 10.

[0125] According to one embodiment, a portion of the optical coupler 42 protrudes from the proximal end of the writing instrument 10 and comprises a hardened transparent material that, in use, can provide tactile feedback to a user of the writing instrument 10 when the protruding portion of the writing instrument 10 is in contact with a substrate of a writing medium tablet.

[0126] Thus, the protruding portion of the optical nib 42 functions as a clear nib for the writing instrument 10. The clear nib directly contacts, for example, the substrate 52. This provides tactile feedback to a user of the writing instrument 10, allowing the feel of a writing medium on a surface to be emulated. The protruding portion of the optical nib 42 may allow the spacing of the writing instrument 10 from the substrate 52 to be predictably adjusted, for example to ensure uniform sizing of the optical nib.

[0127] According to one embodiment, a first light source is fixed to the proximal end P of the writing instrument 10 such that the light source functions as a pen tip that may contact the writing medium. For example, a monochromatic or multi-chromatic LED may be mounted at the proximal end P of the writing instrument 10. In this case, an optical coupler and / or focusing element is not required.

[0128] The protruding portion of the optical tip 42 may be integrally formed with the optical coupler 14 and thus may be formed, for example, from optical glass, plastic, or an encapsulated gel.

[0129] In another example, there is no protruding portion of the optical nib 42. For example, instructions may be provided detailing that the writing instrument 10 should be held within a range of distances from the substrate 52 to ensure a correctly sized optical nib. In another example, the optical nib diameter may be fixed (and thus the focusing element 34 may be non-adjustable). In this case, the size of the optical nib changes by moving the writing instrument 10 closer to or farther from the substrate 52.

[0130] According to one embodiment, the writing instrument 10 further comprises a first modem 28 configured to enable the controller to communicate with an external communication node, or a second modem included within the writing medium 50. For example, the wired modem may be a USB™ modem. For example, the wireless modem may be one of a WiFi™ compatible modem, a Bluetooth™ compatible modem, a Near Field Communication (NFC) modem, or a ZigBee™ modem.

[0131] According to one embodiment, controller 18 is configured to interrogate, via first modem 28, an electronic subsystem of writing medium 50, including substrate 52, and receive writing medium 50 specification data from the electronic subsystem describing at least first and second photochromic materials contained within the substrate of writing medium 50. Controller 18 is configured to calculate required settings for one or more of the first and second color components of the first light source based on the received writing medium specification data.

[0132] In one embodiment, the smartphone, tablet, or personal computer includes an application capable of communicating with the writing instrument 10 via a first modem 28 of the writing instrument 10. The application can control functions of the writing instrument 10, such as color selection, beam size, etc. In an example, the writing instrument 10 is programmed with color and beam size settings via the application, so that the writing instrument 10 does not require a color selector 20 and / or a beam size selector 22. In a further example, the application is configured to perform color setting calculations and communicate output intensity values ​​or sequence display information of the first light source 16 via the first modem 28.

[0133] According to a second aspect, there is provided a method 70 for using a writing instrument 10 configured to emit light to modify an appearance of a substrate including at least one photochromic material, the method comprising: receiving (72) a color setting command from a user of the writing instrument from a user-actuatable color selector of the writing instrument; providing (74) a color setting command to a controller of the writing instrument; Calculating (76) a setting required for at least a first color component emitted by a first light source of the writing instrument; controlling (78) a first light source to emit light including at least a calculated first color component, the first color component being within a first wavelength range that corresponds at least in part to a deactivation spectrum of a first photochromic material of the substrate 52 of the proximity writing medium 50; and positioning (80) a proximal end of a writing instrument against the proximate writing medium 50 so as to expose a substrate of the proximate writing medium 50, which includes at least a first photochromic material, to light generated by the first light source.

[0134] FIG. 5 shows diagrammatically a method 70 according to a second embodiment.

[0135] FIG. 6 illustrates an exemplary method 81 .

[0136] In a first step 82 of the exemplary method 81, the user activates the writing instrument 10 by turning on the device, for example, by using a dedicated power switch (not shown) or by using one of the color selector 20 or beam size selector 22 (if present) as a substitute power switch.

[0137] The desired color may be selected (83) by the user via color selector 20. For example, the user may rotate a color selection wheel until the desired color is displayed on the color selection display of writing instrument 10, or on a connected smartphone or tablet application. It is assumed that substrate 52 of writing medium 50 has been partially or fully pre-activated using UV or UV-A light.

[0138] A user may adjust (84) the nib size using the beam size selector 22. For example, the user may adjust a nib size selection wheel or slider located on the elongated body portion of the writing instrument 10.

[0139] Once a selection is made, a color setting calculation 106 is performed (85) and the first light source 16 is set to emit the calculated color.

[0140] The user then initiates (86) writing medium on substrate 52 of writing medium 50. A sketch or writing medium can be displayed on substrate 52 of writing medium 50 by applying a selected deactivation color to substrate 52.

[0141] The user may, in the example, decide to erase a portion of the substrate 52. Thus, the second light source 24 may, in some circumstances, be activated by the user (87). For example, the user may turn the writing instrument 10 over to bring the distal end of the writing instrument 10 into close proximity (optical contact) with the substrate 52. When the second light source 24 is in close proximity to the substrate 52, the at least one photochromic material included in the substrate 52 is deactivated in the portion of the substrate 52 that is in optical contact with the second light source 24. The user may, in some circumstances, decide to reset (activate) the entire substrate 52 (88), for example, by exposing the substrate 52 to a UV or UV-A wand or light source, or, in the example, by leaving the substrate 52 in direct sunlight for a predetermined period of time.

[0142] A further step of the method comprises: initializing a management application for the writing instrument 10 on a personal computing device or smartphone; Establishing a data communication connection between a personal computing device or smartphone and a controller 18 of the writing instrument 10; selecting, via the management application, one or more parameters of the writing instrument 10, including a desired writing medium color, beam size, and "on" or "off" state of the secondary light source 24, a power management feature of the writing instrument, or a photochromic material configuration of the writing medium 50 selected by the user; The method may further include transmitting the one or more parameters to a controller of the writing instrument and configuring the writing instrument based on the transmitted parameters.

[0143] Thus, when writing instrument 10 is controlled via a smartphone, tablet, or personal computing application, many physical interface features of writing instrument 10, such as color selector 20 and beam size selector 22, may be omitted, which can simplify the design of the stylus itself.

[0144] According to a third aspect, there is provided a photochromic writing system 90 comprising a writing instrument 10 according to the first aspect or an embodiment thereof, and a writing medium 50 comprising a substrate 52 containing at least one photochromic material.

[0145] When in use, the writing instrument 10 is configured to emit light in the visible spectrum from the proximal end P that is capable of inactivating at least one photochromic material contained in the substrate 52 of the writing medium 50, thereby changing the appearance of a portion of the writing medium 50.

[0146] Substrate 52 of photochromic writing system 90 can be selected to include at least one photochromic material that has a maximum deactivation wavelength within the range of wavelengths that corresponds to first light source 16 of writing instrument 10 .

[0147] For example, substrate 52 may include one photochromic material. When substrate 52 includes one photochromic material, the maximum of the deactivation spectrum of the one photochromic material is within one of the wavelength ranges 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, and 625 nm to 700 nm.

[0148] For example, substrate 52 may include a combination of at least first and second photochromic materials having the following deactivation wavelength maxima defined by any combination of ranges from the first and second columns of Table 1:

[0149] [Table 1]

[0150] Substrate 52 of photochromic writing system 90 may include three photochromic materials, in which case first light source 16 of writing instrument 10 (optical stylus, luminescent stylus) may generate light at three spectral maxima corresponding to the three deactivation wavelengths (or wavelength ranges) of the three photochromic materials.

[0151] For example, the photochromic substrate layer 52 may include a mixture of Yamada DAE-0001 (blue), DAE-0012 (magenta), and DAE-0068 (yellow) to obtain a CMY color space. In another example, the photochromic substrate layer 52 includes a mixture of Yamada DAE-0001 (blue), DAE-0004 (red), and DAE-0068 (yellow) available from Yamada Chemical Industry Co., Ltd. Those skilled in the art will appreciate that a wide range of photochromic materials may be applied depending on the intended final color specifications.

[0152] In one embodiment, the writing medium 50 comprises an electronic subsystem 56. The electronic subsystem 56 may include a memory configured to store an identifier or spectral data of at least one photochromic material included in the substrate 52 of the writing medium 50. The writing instrument 10, in one embodiment, is configured to interrogate the electronic subsystem (e.g., via a second modem) and obtain the identifier or spectral data of the at least one photochromic material included in the substrate 52 of the writing medium 50. The controller 18 of the writing instrument 10, and / or a remote application on a smartphone, tablet, or personal computer, may use the identifier or spectral data of the at least one photochromic material included in the substrate 52 of the writing medium 50 to calculate intensity values ​​of the first light source 16 required to obtain one or more desired colors defined by the color selector 20 of the writing instrument 10.

[0153] FIG. 7 illustrates a schematic diagram of a photochromic writing system 90 that includes a writing instrument 10 for applying writing to a photochromic writing medium 50 .

[0154] FIG. 8 illustrates generally a photochromic writing system 90 that includes a writing instrument 10 used to erase a writing medium applied to a photochromic writing medium 50 using a second light source 24 of the writing instrument 10 .

[0155] According to one embodiment of the third aspect, the photochromic writing system 90 further comprises a personal computing device or smartphone. The personal computing device or smartphone is configured to initialize a management application for the writing instrument 10, establish a data communication connection between the personal computing device or smartphone and a controller of the writing instrument 10, and select, via the management application, one or more parameters of the writing instrument 10, including a desired writing medium color, a beam size, and an "on" or "off" state of the second light source, a power management characteristic of the writing instrument 10, or a material composition of the writing medium 50 selected by the user. The personal computing device or smartphone is configured to transmit the one or more parameters to the controller of the writing instrument 10, and the controller is configured to update the writing instrument 10 based on the transmitted parameters.

[0156] According to a fourth aspect, there is provided a computer program element comprising machine executable instructions which, when executed on a computer processor, cause the processor to perform steps according to the method of the second aspect.

[0157] According to a fifth aspect, there is provided a computer readable medium comprising a computer program element of the fourth aspect.

[0158] According to a further aspect, there is provided a writing instrument 10 configured to emit light to change the appearance of a substrate that includes at least one photochromic material, the writing instrument 10 comprising: an elongated body portion 12 that allows a user to grip the writing instrument 10, the body portion having a proximal end P and a distal end D; The device further comprises a first light source 16 configured to emit light from the proximal end, the light including at least a first color component within a first wavelength range 65, the first color component capable of being emitted in a predetermined alternating sequence, the first wavelength range corresponding at least in part to an inactivation spectrum of the first photochromic material 62Y, and a controller 18 configured to receive input from a user and generate a signal to control the first light source based on the received user input.

[0159] It is therefore possible to provide a writing instrument 10 with a monochromatic light emitting source, thus eliminating the need for a color selector and / or controller 18 configured to calculate color settings. According to this aspect, a monochromatic writing medium is available.

[0160] According to a further aspect, a writing medium 50 is provided that includes a substrate 52 containing at least one photochromic material and an electronics subsystem 56. The electronics subsystem 56 may include a memory configured to store an identification or spectral data of the at least one photochromic material included in the substrate 52 of the writing medium 50. In one example, the writing medium 50 includes a second modem that is configured, in response to interrogation by the writing instrument 10, to interrogate the electronics subsystem 56 to obtain an identification or spectral data of the at least one photochromic material included in the substrate 52 of the writing medium 50.

[0161] References throughout the foregoing specification to "one embodiment," "an embodiment," "one example," "an example," "one aspect," or "an aspect" mean that a particular feature, structure, or characteristic described in connection with an embodiment or example is included in at least one embodiment of the disclosure. Thus, the appearances of "in one embodiment," "in an embodiment," "one example," "an example," "one aspect," or "an aspect" in various places throughout this specification are not necessarily all referring to the same embodiment or example.

[0162] Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and / or subcombinations in one or more embodiments or examples.

[0163] It should be understood that the present disclosure can also be defined according to the following embodiments. 1. A writing instrument configured to emit light to change the appearance of a substrate that includes at least one photochromic dye, the writing instrument comprising: an elongated body portion (12) that allows a user to grip the writing instrument, the body portion having a proximal end and a distal end; a first light source configured to emit light in a direction away from the proximal end, the emitted light including at least a first color component within a first wavelength range, the first wavelength range corresponding at least in part to a deactivation spectrum of a first photochromic material; and a controller configured to receive input from a user and generate a signal to control the first light source based on the received user input. 2. A writing instrument as described in embodiment 1, wherein the proximal end houses an optical coupler configured to transmit light to the substrate. 3. A writing instrument as described in embodiment 1 or 2, further comprising a second color component within a second wavelength range, wherein the first and second color components can be emitted simultaneously or in a predetermined alternating sequence. 4. 4. The writing instrument of embodiment 3, wherein each of the first and second wavelength ranges is selected to include a maximum value within one of the ranges: 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, and 625 nm to 700 nm. 5. 5. The writing instrument of embodiment 4, wherein the light emitted by the first light source further comprises a third color component within a third wavelength range. 6. A writing instrument as described in one of the preceding embodiments, wherein the first light source is selected from the group of at least first and second light emitting diodes configured to emit light in the first and second wavelength ranges, full spectrum RGB LEDs, one or more laser light sources, or one or more multi-color LEDs having filtering elements in the first and / or second wavelength ranges. 7. 13. A writing instrument according to any one of the preceding embodiments, further comprising a user-actuatable color selector configured to receive color setting commands from a user of the writing instrument and provide the color setting commands to the controller. 8. A writing instrument as described in embodiment 7, wherein the controller is configured to receive color setting commands from a user-actuable color selector, calculate required settings for one or more of the first and second color components of the first light source, and control the first light source to emit light including the calculated first and second color components. 9. A writing instrument as described in any one of the preceding embodiments, further comprising a focusing element disposed between the first light source and the optical coupler, the focusing element configured to adjust the extent of the irradiated area on the surface of the opposing substrate. 10. A writing instrument as described in embodiment 9, wherein the beam sizing element includes one or more movable lenses aligned on the optical axis between the first light source and the optical combiner, or the beam sizing element includes an aperture. 11. A writing instrument as described in embodiment 9 or 10, further comprising a user-actuable beam size selector capable of receiving a beam size determination command from a user and controlling a beam size determination element to provide a beam size selected by the user, the beam size determination element being actuated by a member actuated via a mechanical linkage to the beam size selector or electronically via a controller. 12. 11. The writing instrument of embodiment 9 or 10, further comprising a second light source capable of generating a further spectrum of light corresponding at least in part to the activation spectra of at least the first and second photochromic dyes, the second light source generating light having a wavelength in the range of 315 to 400 nm. 13. 13. A writing instrument as described in embodiment 12, wherein the second light source is provided at a tip of the writing instrument. 14. 14. The writing instrument of embodiment 12 or 13, wherein the second light source is configured to automatically deactivate when not in contact with the substrate. 15. A writing instrument as described in any one of the preceding embodiments, wherein a portion of the optical coupler protrudes from a proximal end of the writing instrument and comprises a hardened transparent material capable of providing tactile feedback to a user of the writing instrument when, in use, the protruding portion of the optical writing instrument is in contact with a substrate of a writing medium tablet. 16. 13. A writing instrument according to any one of the preceding embodiments, further comprising a wireless or wired communication modem configured to enable the controller to communicate with an external communication node. 17. A writing instrument as described in any one of embodiments 8 to 16, wherein the controller is configured to interrogate an electronic subsystem of a writing medium surface including a substrate via a wireless or wired communication modem and receive writing medium surface specification data from the electronic subsystem describing at least first and second photochromic pigments contained within the substrate of the writing medium surface, and the controller is configured to calculate required settings for one or more of the first and second color components of the first light source based on the received writing medium surface specification data. 18. A method of using a writing instrument according to any one of embodiments 1 to 17 to change the appearance of a substrate containing at least one photochromic dye, comprising: receiving a color setting command from a user of the writing instrument from a user-actuatable color selector of the writing instrument; providing color setting commands to a controller of the writing instrument; Calculating required settings for one or more of a first and a second color component of a first light source of the writing instrument; controlling a first light source to emit light including at least calculated first and second color components, the first color component being within a first wavelength range and the second color component being within a second wavelength range, the first and second color components can be emitted simultaneously or in a predetermined alternating sequence, the first wavelength range corresponding at least in part to a deactivation spectrum of a first photochromic dye and the second wavelength range corresponding at least in part to a deactivation spectrum of a second photochromic dye; and positioning a proximal end of a writing instrument so as to expose a substrate of a proximal writing medium surface, the substrate including at least first and second photochromic dyes, to light generated by a first and / or second light source. 19. initializing a management application for the writing instrument on a personal computing device or a smartphone; Establishing a data communication connection between a personal computing device or smartphone and a controller of the writing instrument; selecting, via a management application, one or more parameters of the writing instrument, including a desired writing medium color, beam size, and "on" or "off" state of the secondary light source, a power management feature of the writing instrument, or a pigment composition of the writing medium surface selected by the user; 20. A method for using a writing instrument as described in embodiment 18, further comprising transmitting one or more parameters to a controller of the writing instrument and configuring the writing instrument based on the transmitted parameters. 20. A photochromic writing system comprising: A writing instrument according to any one of embodiments 1 to 17, a writing surface including a substrate containing a first photochromic dye and a second photochromic dye; A photochromic writing system, wherein the writing instrument is configured, when in use, to emit light in the visible spectrum from an optical coupler at a proximal end capable of inactivating at least one of the first and / or second photochromic pigments contained in a substrate of the writing surface to change the appearance of a portion of the writing surface. twenty one. Further comprising a personal computing device or a smartphone, A photochromic writing system as described in embodiment 20, wherein the personal computing device or smartphone is configured to initialize a management application for the writing instrument, establish a data communication connection between the personal computing device or smartphone and a controller of the writing instrument, and select one or more parameters via the management application, including a desired writing color, beam size, and "on" or "off" state of the second light source, a power management characteristic of the writing instrument, or a pigment configuration of a writing surface selected by the user, the personal computing device or smartphone is configured to transmit the one or more parameters to the controller of the writing instrument, and the controller is configured to update the writing instrument based on the transmitted parameters. 22. A computer program element comprising machine-executable instructions which, when executed on a computer processor, cause the processor to perform the steps recited in embodiment 18 or 19. 23. A computer-readable medium comprising the computer program element of embodiment 22.

[0164] [Table 2]

Claims

1. A writing instrument (10) configured to emit light to change the appearance of a substrate (52) including at least one photochromic material, the writing instrument comprising: an elongated body portion (12) that allows a user to grip the writing instrument, the body portion having a proximal end (P) and a distal end (D); a first light source (16) configured to emit light from the proximal end, the emitted light comprising at least a first color component within a first wavelength range (65), the first wavelength range comprising a spectral maximum within one of the following ranges: 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, or 625 nm to 700 nm; a controller (18) configured to receive input from a user and generate a signal to control the first light source based on the received user input; a user-actuatable color selector (20) configured to receive color setting commands from a user of the writing instrument and to provide the color setting commands to the controller (18).

2. 2. The writing instrument of claim 1, wherein the first light source (16) is further configured to emit light including a second color component within a second wavelength range (67), the second wavelength range corresponding at least in part to a deactivation spectrum of a second photochromic material (62R) of the substrate (52), and the first and second color components can be emitted from the first light source (i) individually, (ii) simultaneously, or (iii) in a predetermined alternating sequence.

3. 3. The writing instrument (10) of claim 1 or 2, wherein the second wavelength range includes a spectral maximum within one of the following ranges: 400 nm to 425 nm, 425 nm to 475 nm, 475 nm to 525 nm, 525 nm to 560 nm, 560 nm to 590 nm, 590 nm to 625 nm, or 625 nm to 700 nm.

4. 10. A writing instrument (10) according to any one of the preceding claims, wherein the first light source (16) is selected from the group of light emitting diodes configured to emit light in at least the first wavelength range, tunable color-changing LEDs, one or more laser light sources, or one or more multicolor LEDs including corresponding filtering elements in at least the first wavelength range.

5. 10. The writing instrument of claim 1, wherein the controller is configured to receive the color setting command from the user-actuable color selector, calculate a required intensity setting for setting at least the first color component of the first light source to enable a desired color to be displayed on a substrate comprising at least one photochromic material, and control the first light source to emit light comprising at least the calculated first color component at the calculated intensity.

6. 10. The writing instrument (10) of any one of the preceding claims, further comprising a focusing element (32) configured to adjust the beam size of the beam from the first light source (16) and thereby adjust the extent of the illuminated area on the surface of the opposing substrate (52).

7. 7. The writing instrument of claim 6, further comprising: a user-actuable beam size selector (22) capable of receiving beam sizing commands from the user, the beam size selector (22) configured to control the focusing element (32) to provide the beam size selected by the user, the focusing element being actuated via a mechanical linkage to the beam size selector or via an electronic actuation member controlled by the controller.

8. 10. A writing instrument (10) according to any one of the preceding claims, further comprising a second light source (24) capable of generating a further spectrum of light corresponding at least in part to the activation spectrum (64) of at least the first photochromic material, said second light source (24) generating light having a component in the wavelength range of 315 to 400 nm.

9. 10. A writing instrument (10) according to any one of the preceding claims, further comprising a first modem (28) configured to enable the controller (18) to communicate with a second modem (56).

10. 10. A writing instrument (10) according to any one of the preceding claims, further comprising a camera (38) for providing feedback to the controller (18) of the color of the substrate (52) obtained while operating the writing instrument (10) in combination with a particular combination of photochromic materials.

11. 1. A method (70) for using a writing instrument (10) configured to emit light to change the appearance of a substrate that includes at least one photochromic material, comprising: receiving a color setting command from a user of the writing instrument from a user-actuable color selector of the writing instrument (72); providing (74) the color setting command to a controller of the writing instrument; Calculating (76) a setting required for at least a first color component emitted by the first light source of the writing instrument; controlling (78) the first light source to emit light including at least the calculated first color component, the first color component being within a first wavelength range that corresponds at least in part to a deactivation spectrum of a first photochromic material of a substrate (52) of a proximity writing medium (50); and positioning (80) the proximal end of the writing instrument relative to the proximal writing medium (50) so as to expose the substrate of the proximal writing medium (50) containing at least the first photochromic material to the light generated by the first light source.

12. initializing a management application for the writing instrument on a personal computing device or smartphone; establishing a data communication connection between the personal computing device or the smartphone and the controller of the writing instrument; selecting, via the management application, one or more parameters of the writing instrument, including a desired writing color, beam size, and "on" or "off" state of a secondary light source, a power management feature of the writing instrument, or a pigment composition of a user-selected writing medium (50); 12. The method (70) for using a writing instrument of claim 11, further comprising transmitting the one or more parameters to the controller (18) of the writing instrument and configuring the writing instrument based on the transmitted parameters.

13. A photochromic writing system (90) comprising: A writing instrument (10) according to any one of claims 1 to 10; a writing medium (50) including a substrate (52) containing at least one photochromic material (62Y); The writing instrument is configured, in use, to emit from its proximal end light in the visible spectrum capable of inactivating at least one photochromic material contained in the substrate of the writing medium (50), thereby changing the appearance of a portion of the writing medium (50).

14. 14. The photochromic writing system (90) of claim 13, wherein the first wavelength range corresponds at least in part to a deactivation spectrum of the first photochromic material (62Y) of the substrate (52).

15. A computer program element or signal comprising machine-executable instructions which, when executed on a computer processor, cause said processor to perform the steps of claim 12.

Images