RU2474865C1 - Electronic device keyboard - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: electronic device keyboard has keys and their displays, which are connected to a unit for random distribution of characters and their corresponding functions on the keys, wherein there are optical channels in the keys between their front surfaces and the displays. To limit the viewing angle of images of characters of the keys, each key has N≥2 separate optical channels with opaque walls, wherein the length of the optical channels of the keys, the linear dimension of a section of the display field in a channel to be viewed, and the linear dimension of the top opening of the optical channel of a key must be made in a given ratio.

EFFECT: more secure input of a personal identification code by a user when using electronic equipment or smaller size of the keyboard while maintaining the security level.

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Description

The invention relates to the field of creating devices for inputting information into electronic technical devices, such as ATMs, electronic combination locks and other multi-user electromechanical systems and electrical appliances.

A well-known keyboard of an electronic device comprising a controller, a data processing device and keys with keyboard heads, configured to output symbols to the keys with their respective functions, to change the characters of each of the keys and their corresponding functions. A mini-display connected to the controller and the data processing device is located in the keyboard head of the keyboard, the screen of which goes to the front surface of the keyboard head (RF patent No. 2214619, IPC G06F 3/00, published on October 20, 2003).

The disadvantage of this device is the low security of user typing, since the length of the optical channels of the keys is small compared to the size of their cross sections (despite the location of the images of characters in the lower parts of the keys), which does not provide a sufficient narrowing of the viewing angle of the images of the characters of the keys. In this case, it becomes possible to disclose the access password by a third-party observer located next to the operator dialing the code. Another disadvantage of this keyboard is the lack of random distribution of characters and their corresponding functions on the keys.

The keyboard of an electronic device is known (RF patent No. 2377636, IPC G06F 3/00, publ. 12/27/2009), which is selected as a prototype, containing keys with displays, configured to output keys to characters with corresponding functions, change key characters and their respective functions. The keys and their displays are connected to a block of random distribution of characters and their corresponding functions on the keys. The keys between the front surfaces and displays are made of optical channels, the length of which 1 satisfies the ratio:

,

,

where d is the diameter of the circle described around the image of the key sign, mm;

h is the maximum deviation of the axis of the optical channel of the key from the center of the typing field of the keyboard, mm;

m is the coefficient of increase in the upper hole of the optical channel of the key selected from the expression:

.

.

where D is the diameter of the circle described around the upper hole of the optical channel of the key, mm

The disadvantage of this keyboard is the increased length of the optical channel of the keys, necessary to provide the required viewing angle of the key symbols based on security considerations for typing the code. This parameter is commensurate with the transverse dimensions of the key and can be several times higher than it. As a result, the height of the keys and the thickness of the keyboard increases, which in some cases may limit its use. A decrease in the length of the optical channel of the keys relative to the calculated value is accompanied by an increase in the viewing angle of the key symbols and a decrease in the security of the code set.

The objective of the invention is to increase the level of secrecy of code input for a given size of the keyboard, or to reduce the size of the keyboard while maintaining the level of secrecy.

The problem is achieved in that the keyboard of the electronic device, as in the prototype, contains keys and their displays connected to a random distribution of characters and their corresponding functions among the keys, and optical channels are made in the keys between their front surfaces and displays.

According to the invention, N≥2 separate optical channels with opaque walls, the lengths of which 1 satisfy the relation

,

,

where q is the maximum linear size of the portion of the display field open for viewing in the optical channel in a plane passing through the axis of the optical channel and the optical center of the operator, mm;

h is the maximum deviation of the axis of the optical channel of the key from the center of the typing field of the keyboard, mm;

m is the coefficient of excess of the linear size of the upper hole of the optical channel of the key (Q) over the linear size q in the plane passing through the axis of the optical channel and the optical center of the observer, the value of which is selected from the expression

,

,

where Q is the linear size of the upper hole of the optical channel of the key in the plane passing through the axis of the optical channel and the optical center of the observer, mm

Using keys with several separate optical channels allows you to achieve the effect of hiding the characters at a given viewing angle, since part of the character is overlapped by the opaque walls of the optical channels. In this case, the user can enter the required sequence of characters of the code, which cannot be seen by an outside observer. In this case, it is possible to see the symbol only at a smaller viewing angle, which increases the privacy of entering the user's personal data.

Figure 1 shows the possible placement of the images of the signs of the keys on the typing field of the keyboard before performing the operation of entering the code.

Figure 2 shows the design of the key with four optical channels.

Figure 3 presents a variant of the location of the optical center of the operator at the border of the field of view of the section of the key symbol, the most remote from the middle of the typing field of the keyboard.

Figure 4 shows a variant of the location of the optical center of the third-party observer at the border of the field of view of the section of the key symbol, the most remote from the middle of the typing field of the keyboard.

Figure 5 shows the key farthest from the optical center of the operator.

Figure 6 shows the key closest to the optical center of the third-party observer.

Figure 7 shows the possible placement of the images of the characters of the keys on the typing field of the keyboard when the code entry operation is repeated.

The proposed keyboard of the electronic device 1 contains a dial-up field 2 (Fig. 1), on which a predetermined number of keys 3 with separate optical channels 4 are placed, through which sections of images of symbols 5 corresponding to certain functions of keys 3 are visible.

The keys 3 (Fig. 4) are made with separate optical channels 4, through which parts of the symbols 5 are visible on the displays 6 located in the lower part of the keys 3. The walls 7 of the optical channels 4 are made opaque. In the simplest case, they can be inserts of a thin opaque material. The walls 7 of the optical channels 4 and the body of the keys 3 can be made as a single unit. The front surface of the keys 3 is made transparent. The cross section of the optical channels 4 may be different, for example, rectangular, triangular, octagonal and others. As displays 6, any known design for its implementation can be used, for example, liquid crystal, LED, fiber-optic, gas-discharge, and others.

The distribution of characters 5 and their corresponding functions by keys 3 is implemented using a random distribution of characters and their corresponding functions by keys (not shown), which is in electrical communication with the keys 3 and their displays 6. Block of random distribution of characters 5 and their corresponding functions by keys 3 can be made in the form of a random number generator (“white noise” generator) or in the form of a microcontroller with appropriate software. This unit can be placed both in the keyboard case of the electronic device and outside it.

The proposed device keyboard electronic devices can be located both in the same housing with an electronic device (ATM, cell phone), and separately (computer keyboard).

Figure 3 presents the case when the optical center of the operator (point O _about ) is located opposite the middle of the typing field of the keyboard (point s). In this case, the axis 8 of the optical channel farthest from the middle s of the typing field of the keyboard is offset by a distance h from O _o -s passing through the optical center of the operator O _o . From the geometric relationships shown in figure 3, it follows that the image of the part of the symbol in the area a-b of the display 6 for the optical channel farthest from the middle s of the typing field of the keyboard will be fully visible to the operator provided:

where l is the length of the optical channel of the key, mm;

L _o - the distance from the optical center of the operator O _about to the plane of the keyboard typing field, mm;

Q is the linear size of the upper hole of the optical channel of the key in the plane passing through the axis of the optical channel and the optical center of the operator, mm;

q is the maximum linear size of the portion of the display field open for viewing in the optical channel in a plane passing through the axis of the optical channel and the optical center of the operator, mm;

h is the maximum deviation of the axis of the optical channel of the key from the center of the typing field of the keyboard, mm;

d is the diameter of the circle described around the image of the key sign, mm.

When the optical center of the outside observer (point O _n ) is located at a distance H (Fig. 4) from the middle s of the keyboard typing field in the vw plane parallel to the sr plane of the keyboard typing field. It follows from the geometric relationships that the image of a part of the symbol in section a-b for the optical channel closest to the observer and farthest from the center of the type-setting field will be completely invisible to the outside observer provided:

where L _n - the distance from the optical center of the observer to the plane of the typing field of the keyboard, mm;

H is the minimum deviation of the optical center of the observer from the center of the typing field of the keyboard in a plane parallel to the plane of the typing field of the keyboard, mm;

d is the diameter of the circle described around the image of the key sign, mm.

The analysis of expressions (1), (2) shows that both requirements for the length of the optical channels of the keys can be fulfilled simultaneously if the ratio of a number of geometric sizes is ensured in accordance with the expression:

where m is the coefficient of excess of the linear size Q of the upper hole of the optical channel of the key over the linear size q in the plane passing through the axis of the optical channel and the optical center of the observer, the coefficient of increase of the upper hole of the optical channel of the key;

Q is the linear size of the upper hole of the optical channel of the key in the plane passing through the axis of the optical channel and the optical center of the observer, mm;

n = L _o / L _n - the ratio of the distance from the optical center of the operator L _o to the plane of the keyboard typing field to the distance from the optical center of the observer L _n to the plane of the keyboard typing field.

Using expressions (1), (2), (3), it is possible to determine the size of the keyboard’s typing field (characterized by the parameter h), the cross-sections of the individual optical channels of the keys (characterized by the parameters q, Q), and the length of the optical channels of the keys l, which provide hidden from an outside observer operator typing with possible options for the location of the operator and the outside observer relative to the typing field of the keyboard (characterized by the parameters L _о , L _n , H).

Based on the probable approach of an outside observer to the operator, it is possible to take the parameter H equal to 500 mm. Taking into account that, ceteris paribus, the greatest value of the lower limit of the length of the optical channel of the key is achieved at a maximum distance from the optical center of the observer to the plane of the keyboard’s typing field L _n.max , which for a person is about 600 mm, and the minimum value of the upper boundary of the length the optical channel of the key is achieved with a minimum distance from the optical center of the operator to the plane of the keyboard’s typing field L _o.min , which for a person is about 450 mm, you expressions (1), (2), (3) can be transformed to the form:

Therefore, using dependencies (4), (5), (6), it is possible to determine the main structural dimensions of the keyboard’s typing field and the optical channels of the keys to achieve the secrecy of entering a personal identifier code by a user of electronic technical devices.

The geometric parameters of the optical channels 4 of the keys 3 provide an overview of the parts of the symbols on the display 6 even in the most distant optical channels from the middle of the dialed field (point s) when the operator is placed opposite the dialed field (the optical center of the operator at the point О _о ), as shown in FIG. 5. Most of the symbol sections on the display 6 are not visible to an outside observer located next to the operator (the optical center of the observer at the point О _н ), even in the channels 4 closest to the observer, as shown in Fig.6.

An increase in the number of optical channels 4 in the keys 3 is accompanied by a decrease in the length of the optical channels 4 necessary to ensure the required angle of view for the symbols 5 of the keys 3 and, accordingly, the secrecy of the code entry, which allows reducing the dimensions of the proposed keyboard of the electronic device.

The work of the proposed keyboard electronic device is as follows.

The operator is located at the typing field 2 of the keyboard 1 with a limited viewing angle of images of symbols 5 keys 3 in the area of their free viewing in the optical channels 4 on the displays 6 of the keys 3 opposite the middle s of the typing field 2 of the keyboard 1 (Fig.3, 5). The operator performs preliminary procedures prior to entering the code (recognition of the identification card, starting the process of entering the code, etc.).

After that, the random distribution unit randomly generates an arrangement of images of symbols 5 on displays 6 of keys 3, which are assigned functions corresponding to images of symbols 5 displayed on displays 6 of keys 3, for example, as shown in FIG. 1.

Then the operator enters the desired sequence of code characters, for example 7018 (the keys 3 pressed when this is highlighted in figure 1). The block of random distribution of characters and their corresponding functions compares the pressed key 3 with the function assigned to it and transmits signals about keystrokes to external devices (ATM, electronic combination lock, etc.) that use the keyboard of the electronic device as an input tool.

An outside observer located outside the free viewing area of the images of symbols of the 5 keys 3 (Figs. 4, 6) sees only the inner surface of the optical channels 4 of the keys 3 in the area a-e lying outside the zone containing basic information about the symbols 5 on the display 6. An outside observer fixes only the placement of the pressed keys 3 on the keyboard (highlighted in color in Fig. 1) and the sequence of their pressing, but cannot match the placement of the keys 2 with the images of characters 5.

When an outside observer tries to reproduce the input of code 7018, he starts the process of entering the code, after which the location of the images of characters 5 on the displays 6 of keys 3 is randomly generated on the code input keyboard by the random keyboard and they are assigned functions corresponding to the images of characters 5 on the displays 6 of keys 3, for example, as shown in Fig.7. Moreover, the location of the images of characters 5 keys 3 on the keyboard 1 (Fig.7) in this case will not coincide with the previous location of the images of characters 5 keys 3 (Fig.1). Therefore, the set of previously observed sequence of pressed keys 3 will not give the desired result - entering the correct sequence of characters. In this case, the number 20_7 will be dialed, which does not correspond to the required code. To dial the correct code 7018 on the newly formed typing field 2 of the keyboard 1 (Fig. 7), press the 3 keys highlighted in color, and in the required sequence, which cannot be known to an outside observer in advance.

Using the proposed keyboard of an electronic device provides increased privacy for the user to enter a personal identifier code or other personal data when working with electronic technical devices, which prevents unauthorized access of third parties to protected objects and closed electronic information.

In addition, the proposed keyboard allows to reduce the length of the optical channels of the keys, and therefore, the dimensions of the keyboard while maintaining at the initial level of secrecy of entering personal user data when working with electronic technical devices.

Claims (1)

A keyboard of an electronic device containing keys and their displays connected to a block of random distribution of characters and their corresponding functions into keys, moreover, optical channels are made in the keys between their front surfaces and displays, characterized in that N≥2 separate optical channels are made in each key with opaque walls, the lengths of which 1 satisfy the ratio:

where q is the maximum linear size of the portion of the display field open for viewing in the optical channel in a plane passing through the axis of the optical channel and the optical center of the operator, mm;
h is the maximum deviation of the axis of the optical channel of the key from the center of the typing field of the keyboard, mm;
m is the coefficient of excess of the linear size of the upper hole of the optical channel of the key (Q) over the linear size q in the plane passing through the axis of the optical channel and the optical center of the observer, the value of which is selected from the expression:

where Q is the linear size of the upper hole of the optical channel of the key in the plane passing through the axis of the optical channel and the optical center of the observer, mm

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