Methods for physically verifying the operating mode of a screen and its use

Abstract

Method for physically verifying an operating mode of a screen (1) that can be operated in two operating modes, B1 for a free viewing mode and B2 for a restricted viewing mode, wherein a switching between the operating modes B1 and B2 involves at least one step A) of switching on or off light sources (2), and wherein the light generated by the light sources (2) is fed into a transparent light guide (3), comprising the following steps at a selectable time after said step A): B) Determining a brightness value H at at least one point P of at least one surface and / or edge of the transparent light guide (3) by means of at least one light-sensitive sensor (4), wherein said light-sensitive sensor (4) corresponds to at least one of the light sources (2), which for this purpose is operated as a light-sensitive sensor (4) in a light-sensitive mode for the duration of the determination of the brightness value H, C) Comparison of the brightness value H with a target value range S, whereby the result of the check is that operating mode B1 is present when the brightness value H is outside the said target value range S, and that operating mode B2 is present when the brightness value H is within the said target value range S.

Description

State of the art

[0001] The applicant's WO 2015 / 121398 A1 describes a screen for a free view mode and a restricted view mode, whereby a light guide for the restricted view mode must not be exposed to light. A disadvantage here is that if components fail, such as LEDs or control electronics, the privacy mode cannot be automatically checked without an operator.

[0002] The applicant's WO 2017 / 097975 A1 describes a screen for a free view mode and a restricted view mode, with a light guide for the restricted view mode being exposed to light. This technology also has the inherent disadvantage that in the event of component failures, such as LEDs or control electronics, the privacy mode cannot be automatically checked without an operator.

[0003] US 2010 / 0134525 A1 discloses a method for testing a (standard) backlight by measuring the light emitted by it (or alternatively, the electrical power consumed). This method only concerns the detection of malfunctions that result in degraded illumination by the backlight. However, the document does not disclose a method for detecting a possible system error (which could be caused by mechanical influences, for example), especially if this leads to a degraded privacy effect, for example, in a dual backlight.

[0004] Furthermore, US2010 / 0225640 A1 describes various control options for LCD screens, which offer transmissive, reflective, and transflective operating modes, with environmental conditions in particular influencing the choice of operating mode. The corresponding teaching does not disclose any way to detect system errors in switchable privacy screens or backlights.

[0005] US 2014 / 0002428 A1 describes methods for dynamically adjusting a screen's brightness, particularly based on ambient light sensor readings. This document also does not disclose any way to detect system errors in switchable privacy screens or backlights.

[0006] A disadvantage of these and other prior art methods for such screens is that the presence of the privacy mode cannot be easily verified. However, this is necessary, for example, for transaction-relevant systems such as ATMs or payment terminals. Description of the invention

[0007] It is therefore an object of the invention to disclose a method for physically checking the operating mode of a screen that can be operated in at least two operating modes: B1 for a free view mode and B2 for a restricted view mode. This method should not require a user or operator on-site for the check. Furthermore, the invention should require little space and no parts or components outside the volume of the respective screen.

[0008] This object is achieved according to the invention by a method for physically checking the operating mode of a screen which can be operated in at least two operating modes, B1 for a free view mode and B2 for a restricted view mode, wherein the switching between the operating modes B1 and B2 involves at least the step A) of switching on or off lamps whose light is fed into a transparent light guide, comprising the following steps at a selectable time after said step A): B) Determining the brightness value H at at least one point P of at least one surface and / or edge of the transparent light guide by means of at least one light-sensitive sensor, wherein said light-sensitive sensor corresponds to at least one of the illuminants, which is operated as a light-sensitive sensor in a light-sensitive mode for the duration of the determination of the brightness value H, ## C) Comparison of the brightness value H with a setpoint range S, whereby the result of the check is that operating mode B1 is present if the brightness value H is outside the said setpoint range S and that operating mode B2 is present if the brightness value H is within the said setpoint range S.

[0009] Normally, the brightness value is measured as illuminance (in Ix) or, if necessary, as luminous flux or other photometric quantity or converted accordingly.

[0010] In particular, the at least one light-sensitive sensor corresponds to at least one of the light sources, which is operated in a light-sensitive mode for this purpose. This is possible, for example, with an LED. For example, if several LEDs are present, some of these LEDs could serve as light-sensitive sensors for the duration of determining the brightness value H, while the other LEDs continue to emit light.

[0011] The method according to the invention gains particular importance in an embodiment in which step B) is carried out at least twice in succession at at least two defined times T1, T2, ... after step A) to determine brightness values ​​H1, H2, ..., wherein optionally the illuminants emit defined luminous values ​​L1, L2, ..., which may be different from one another, at the defined times T1, T2, ..., to which corresponding target value ranges S1, S2, ... then correspond.

[0012] For example, a defined time-modulated PWM signal can be applied to the lamps to check whether the control electronics of the lamps have been tampered with or whether all original components are still present. The defined time-modulated PWM signal can also be varied over time if necessary: ​​for example, a different PWM signal is applied and checked for each day or each week.

[0013] Alternatively, in this embodiment, the luminous values ​​L1, L2, ... can also be emitted by the lamps at intervals of time, e.g., within a few seconds - preferably very briefly, i.e., for 0.05 s - in order to repeatedly verify the viewing mode B2, e.g., during the use of an ATM.

[0014] In this embodiment, all brightness values ​​H1, H2, ... should advantageously be compared with the setpoint ranges S1, S2, ... In this case, it is only reliably determined that operating mode B2 is present if all brightness values ​​H1, H2, ... are within the respective setpoint ranges S1, S2, ...

[0015] In a first embodiment of a corresponding screen, the corresponding lamps, which are crucial for switching the operating mode, are switched off for operating mode B2. An example structure for such a screen can be found in WO 2015 / 121398 A1. This document describes a screen for a free view mode and a restricted view mode, whereby the light guide for the restricted view mode must not be exposed to light. Accordingly, the target value range S will only allow a small brightness value H, which takes into account a tolerance of light captured in the light guide from the image display and ambient light.

[0016] In a second embodiment of the screen, the lamps are switched on for operating mode B2. An exemplary structure for such a screen can be found in WO 2017 / 09795 A1. This describes a screen for a free and a restricted view mode, whereby the corresponding light guide for the restricted view mode, which is crucial for switching the operating mode—in contrast to the first embodiment—must be exposed to light. Accordingly, the target value range S represents a minimum brightness value, because a brightness value H that is too low would mean that not enough light is coupled into the relevant light guide to achieve the privacy effect.

[0017] Further design variants provide that the setpoint range S or, if available, the setpoint ranges S1, S2, ..., are dynamically variable in order to be adapted for different brightnesses of the screen.

[0018] The implementation of step C) can be done, for example, in software and / or electronics.

[0019] The screen may also correspond to a static image.

[0020] The method according to the invention is advantageously used in a device for processing payment-relevant processes and / or for depositing or withdrawing money or in a vehicle.

[0021] In principle, the performance of the invention is maintained if the parameters described above are varied within certain limits.

[0022] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations indicated, but also in other combinations or on their own, without departing from the scope of the present invention.

[0023] The invention is explained in more detail below with reference to drawings which also show features essential to the invention.

[0024] It shows Fig. 1 is a schematic diagram of the method according to the invention, applied to a screen with a light guide arranged behind a backlit image generator in the viewing direction, the screen being operated in free view mode B1, Fig. 2 shows a schematic diagram of the method according to the invention, applied to a screen with a light guide arranged behind a backlit image generator in the viewing direction, the screen being operated in the restricted viewing mode B2, Fig. 3 a schematic diagram of the method according to the invention, applied to a screen with a light guide arranged in front of an image generator in the viewing direction, wherein the screen is operated in the restricted view mode B2, and Fig. 4 a schematic diagram of the method according to the invention, applied to a screen with a light guide arranged in front of an image generator in the viewing direction, wherein the screen is operated in free view mode B1.

[0025] The drawings are not to scale and only represent schematic diagrams.

[0026] In Fig. Figure 1 shows a schematic diagram of the method according to the invention, applied to a screen 1 with a light guide 3 arranged behind a backlit image sensor 5 in the viewing direction, wherein the screen 1 is operated in free view mode B1. An exemplary first embodiment of such a screen 1, or a backlight switchable between two operating modes B1 and B2, can be found in further detail in WO 2015 / 121398 A1 by the applicant. Other embodiments are of course possible. For the free view mode B1, the (directed) backlight 6 is switched off, while the lamps 2 are switched on. These lamps feed light into the light guide 3—which is crucial for switching between operating modes B1 and B2—which radiates the light through an image generator 5, such as an LCD panel, into a wide viewing area. At least one light-sensitive sensor 4, e.g., an LED serving as a light source, is then arranged at a coupling edge of the light guide 3 to detect the brightness value H at at least one point P on the light guide 3. Of course, several LEDs can also be used as light-sensitive sensors 4. Due to the coupling of light from the lamps 2 into the light guide 3—which is desired for operating mode B1—the determined value H will be rather high here; it can be several hundred thousand or million μm / m. 2(corresponds to the unit Ix). Such a value would result, for example, if 40 LEDs, each with 40 lm, coupled light into a 120 mm long light guide 3, wherein the light guide is 2 mm thick and wherein approximately 90% of the light is coupled out of the light guide 3 due to outcoupling structures and approximately 10% of the coupled light leaves the edge of the light guide 3 opposite the coupling side.

[0027] An exemplary setpoint range S for the operating mode B2 will have a small value in this embodiment, e.g. less than 1,000 or less than 10,000 Ix, because otherwise too much light from the light guide 3 is emitted by the imager 5 in wide angles.

[0028] Thus, the above-mentioned (assumed) determined value H lies outside the setpoint range S, and the physical verification confirms that operating mode B1 is present, because several hundred thousand Ix are greater than, for example, ten thousand Ix. Other value relationships are, of course, possible.

[0029] In contrast, the Fig. 2 shows a schematic diagram of the method according to the invention, applied to a screen 1 with a light guide 3 arranged behind a backlit image generator 5 in the viewing direction, wherein the screen 1 is operated in the restricted view mode B2. The structure is therefore the same as above for Fig. 1, with the difference that the lamps 2 are now off and the directed backlight 6 is switched on. Due to the directed backlight 6 and the transparent light guide 3, the restricted viewing mode B2 is achieved. However, this only applies if, as far as possible, no light is emitted from the light guide 3 at wide angles. The inventive method for physically checking an operating mode of a screen 1 that can be operated in at least two operating modes, B1 for a free viewing mode and B2 for a restricted viewing mode, wherein switching between the operating modes B1 and B2 involves at least step A) of switching lamps 2, whose light is fed into a transparent light guide 3, on or off, then again comprises the following steps at a selectable time after said step A): B) Determining the brightness value H at at least one point P of at least one surface and / or edge of the transparent light guide 3 by means of at least one light-sensitive sensor, wherein said light-sensitive sensor corresponds to at least one of the illuminants, which is operated as a light-sensitive sensor in a light-sensitive mode for the duration of the determination of the brightness value H, C) Comparison of the brightness value H with a setpoint range S, whereby the result of the check is that operating mode B1 is present if the brightness value H is outside the said setpoint range S and that operating mode B2 is present if the brightness value H is within the said setpoint range S.

[0030] At least one light-sensitive sensor 4, e.g. an LED of the light source 2 operated in light-sensitive mode, is then arranged at the coupling edge of the light guide 3 in order to detect the brightness value H at at least one point P of the light guide 3.

[0031] An exemplary target value range S for operating mode B2 will, as already noted above, have a rather low value, e.g., less than 1,000 or less than 10,000 Ix, because otherwise too much light from the light guide 3 would be emitted by the imager 5 at wide angles. Due to the coupling of light from the lamps 2 into the light guide 3—which is undesirable for operating mode B2—the value H here will actually be rather low, e.g., 500 Ix. Thus, it lies within the target value range S, and the physical verification confirms that operating mode B2 is present.

[0032] The method according to the invention gains particular importance in an embodiment in which step B) is carried out at least two or more times in succession at at least two defined times T1, T2, ... after step A) to determine brightness values ​​H1, H2, ..., wherein optionally the illuminants 2 emit defined luminous values ​​L1, L2, ..., which are preferably different from one another, at the defined times T1, T2, ...

[0033] For example, a defined time-modulated PWM signal can be applied to the lamps 2 to check whether the control electronics of the lamps 2 have been tampered with or whether all original components are still present. The defined time-modulated PWM signal can also be varied over time, if necessary; for example, a different PWM signal is applied and checked for each day or each week.

[0034] In this embodiment, all brightness values ​​H1, H2, ... should advantageously be compared with the respective target value ranges S1, S2, ...

[0035] It is only reliably determined that operating mode B2 is present if all brightness values ​​H1, H2, ... are within the respective setpoint ranges S1, S2, ...

[0036] In a second embodiment of the screen 1, which is shown in the Fig. 3 and Fig. As illustrated in Figure 4, the lamps 2 are switched on for operating mode B2. An exemplary structure for such a screen 1 can be found in WO 2017 / 09795 A1. This describes a screen for a free and a restricted viewing mode, wherein a light guide 3 is exposed to light for the restricted viewing mode. The light is then emitted from the light guide 3 primarily to the sides, but not to the front, in order to outshine the image to the sides while still being perceptible from the front. This allows for a privacy screen, i.e., operating mode B2, to be generated. Fig. Figure 3 now shows a corresponding schematic diagram of the method according to the invention, applied to a screen 1 with a light guide 3 arranged in front of an image generator 5 in the viewing direction, wherein the screen 1 is operated in the restricted view mode B2. Here, too, at least one light-sensitive sensor 4, e.g., an LED of the illuminating means 2 operated in the light-sensitive mode, is arranged at the coupling edge of the light guide 3 in order to detect the brightness value H at at least one point P of the light guide 3.

[0037] According to the invention, the following steps are now carried out: A) Switching on lamps 2, whose light is fed into a transparent light guide 3 to activate the operating mode B2, B) Determining the brightness value H at at least one point P of at least one surface and / or edge of the transparent light guide 3 by means of at least one light-sensitive sensor 4, wherein said light-sensitive sensor 4 corresponds to at least one of the illuminants 2, which is operated as a light-sensitive sensor in a light-sensitive mode for the duration of the determination of the brightness value H, C) Comparison of the brightness value H with a setpoint range S, whereby the result of the check is that operating mode B1 is present if the brightness value H is outside the said setpoint range S and that operating mode B2 is present if the brightness value H is within the said setpoint range S.

[0038] The target value range S for operating mode B2 will have a rather high value, e.g., one hundred thousand Ix (or alternatively even one or more million Ix), because otherwise too little light will be emitted from the light guide 3 above the imager 5 in lateral angles (but preferably not frontally), thus creating the restricted view due to cross-fading to the sides. Due to the coupling of light from the lamps 2 into the light guide 3 - which is desired for operating mode B2 - the structure according to Fig. 3 With the lamps 2 switched on, the value H here actually falls within this range, provided the lamps 2 are operating correctly; the value H can be, for example, 500,000 Ix (or, alternatively, 2,500,000 Ix). Thus, it lies within the target value range S proposed for this second embodiment, and the physical verification demonstrates that operating mode B2 is actually present.

[0039] The Fig. Figure 4 shows a schematic diagram of the method according to the invention, applied to a screen 1 with a light guide 3 arranged in front of an image generator 5 in the viewing direction, wherein the screen 1 is operated in free view mode B1. Since the lamps 2 are switched off here, a sensor 4, wherein the said light-sensitive sensor 4 corresponds to at least one of the lamps 2, determines at point P a low value H, for example 500 Ix or 2,000 lux, which results from residual light tolerances due to light captured in the light guide 3. The captured light is caused, among other things, by ambient light and the image displayed on the screen 1. Thus, H is outside the setpoint range and operating mode B1 is verified.

[0040] As described above, the given values ​​for the brightness value H and the target value range S are merely examples. Other values ​​and value ranges are of course possible.

[0041] Further design variants provide that the setpoint range S or, if present, the setpoint ranges S1, S2, ..., are dynamically variable in order to be adapted for different brightnesses of the screen 1.

[0042] The method according to the invention is advantageously used in a device for processing payment-relevant processes and / or for depositing or withdrawing money or in a vehicle.

[0043] The method described above solves the stated problem: A method for physically testing the operating mode of a screen that can be operated in at least two modes: B1 for a free view mode and B2 for a restricted view mode. No user or operator needs to be on-site for the test. Furthermore, the invention requires little space and no parts or components outside the volume of the respective screen.

Claims

[1] Method for physically checking an operating mode of a screen (1) which can be operated in two operating modes, B1 for a free view mode and B2 for a restricted view mode, wherein switching between the operating modes B1 and B2 involves at least one step A) of switching on or off lighting means (2), and wherein the light generated by the lighting means (2) is fed into a transparent light guide (3), comprising the following steps at a selectable time after said step A): B) Determining a brightness value H at at least one point P of at least one surface and / or edge of the transparent light guide (3) by means of at least one light-sensitive sensor (4), wherein said light-sensitive sensor (4) corresponds to at least one of the illuminants (2), which is operated as a light-sensitive sensor (4) in a light-sensitive mode for the duration of the determination of the brightness value H, C) Comparison of the brightness value H with a setpoint range S, whereby the result of the check is that operating mode B1 is present if the brightness value H is outside the said setpoint range S and that operating mode B2 is present if the brightness value H is within the said setpoint range S. [2] Method according to claim 1, characterized bythat step B) is carried out at least twice in succession at least two defined times T1, T2, ... after step A) to determine brightness values H1, H2, ..., wherein optionally the illuminating means (2) emit defined luminous values L1, L2, ..., which are preferably different from one another, at the defined times T1, T2, ... [3] Method according to claim 2, characterized by that all brightness values H1, H2, ... are compared with setpoint ranges S1, S2, ... and it is only determined that operating mode B2 is present if all brightness values H1, H2, ... are within the respective setpoint ranges S1, S2, ... [4] Method according to one of the preceding claims, characterized by that for operating mode B2 the lamps (2) are switched off. [5] Method according to one of claims 1 to 3, characterized by that the lamps (2) are switched on for operating mode B2. [6] Method according to one of the preceding claims, characterized by that the setpoint range S or, if present, the setpoint ranges S1, S2, ... are dynamically variable in order to be adapted for different brightnesses of the screen (1). [7] Use of the method according to one of the preceding claims in a device for processing payment-related processes and / or for depositing or withdrawing money or in a vehicle.

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