A virtual touch button and integrated stove based on infrared detection

Abstract

The utility model relates to a virtual touch key and an integrated stove based on infrared detection, comprising a vertical touch surface, the touch surface having a key pattern; a switch plate is horizontally placed on the upper part of the touch surface, the switch plate partially or completely extends out of the touch surface, and a sensor component is correspondingly arranged at a position above each key pattern in the extended part; each sensor component comprises at least an infrared receiving tube arranged above the central axis of the key pattern, and two infrared transmitting tubes symmetrically arranged on both sides of the infrared receiving tube, the infrared transmitting tube and the infrared receiving tube are arranged in a row and parallel to the touch surface, and the two infrared transmitting tubes separated on the left and right sides are configured to emit light beams to jointly form an infrared detection three-dimensional area of ​​L*W*H, wherein the height L and the width W of the detection three-dimensional area are respectively equivalent to the maximum height and the maximum width of the key pattern, and the farthest detection distance H of the detection three-dimensional area from the touch surface is between 4-9.8mm.

Description

Technical Field

[0001] The utility model relates to a key switch technology, in particular to a virtual touch key and an integrated stove based on infrared detection. Background Art

[0002] With the development of smart home, industrial automation, medical equipment and other fields, the demand for contactless, high-precision and high-reliability input devices is increasing. At the same time, special attention is paid to user experience. For example, the need for use in special environments (such as hygiene-sensitive areas and severe outdoor weather conditions) has prompted the search for new ways of interaction.

[0003] Capacitive touch buttons are widely used, but they rely on a conductor (usually the human body) to change capacitance, which limits their use scenarios. For example, they may not work properly when wearing gloves or in a humid environment. In addition, capacitive touch buttons are affected by electrostatic discharge (ESD) and electromagnetic interference (EMI), which reduces reliability. After long-term use, capacitive touch panels may experience problems such as decreased sensitivity or false triggering.

[0004] Infrared reflection technology is not affected by non-conductive obstacles (such as gloves and water droplets), expanding its application scenarios.

[0005] CN102340300A discloses a reflective infrared touch button. The light beams of the infrared transmitting tube and the receiving tube are perpendicular to the touch surface, which has defects such as glare and susceptibility to interference. At the same time, the optical device is difficult to hide, and the design requirement of no device when viewed from the front cannot be achieved.

[0006] JP1995030435U discloses another operation switch based on infrared reflection. The light beams of the transmitting tube and the receiving tube are arranged parallel to the touch surface. However, only a sensing structure of a single transmitting tube and a single receiving tube is adopted. Moreover, the sensing structure needs to detect touch targets at multiple locations ABC. The detection area formed by the light beam of the transmitting tube is large, and it is difficult to ensure the switch accuracy, which is prone to false triggering due to interference. Utility Model Content

[0007] The utility model aims to improve the anti-interference ability of the key on the basis of realizing the touch key based on the infrared reflection technology, to achieve high-precision and high-reliability key switch operation, while taking into account the user experience.

[0008] To this end, a virtual touch key based on infrared detection is provided, comprising a touch surface arranged vertically, wherein the touch surface is provided with at least one key pattern; a switch plate is horizontally placed on the upper part of the touch surface, the switch plate partially or completely extends out of the touch surface, and a sensor component is correspondingly arranged in the extended part above each key pattern; each sensor component comprises at least one infrared receiving tube arranged above the central axis of the key pattern, and two infrared transmitting tubes symmetrically arranged on both sides of the infrared receiving tube, the infrared transmitting tube and the infrared receiving tube are arranged in a row parallel to the touch surface, and the two infrared transmitting tubes separated on the left and right sides are configured to emit light beams to jointly form an infrared detection three-dimensional area of ​​L*W*H, wherein the height L and the width W of the detection three-dimensional area are respectively equivalent to the maximum height and the maximum width of the key pattern, and the farthest detection distance H of the detection three-dimensional area from the touch surface is between 4-9.8 mm.

[0009] Furthermore, the emission angle of the infrared emitting tube is between 5°-15°, the emission normal is parallel to the touch surface, and the distance between the two infrared emitting tubes and the touch surface is controlled between 2-8mm. To achieve the best effect, the maximum detection distance H is configured to be 4mm, the emission angle of the infrared emitting tube is configured to be 10°, and the infrared emitting tube is 2mm away from the touch surface.

[0010] Furthermore, it also includes an adjustable current source, which is coupled to the infrared emitting tube and is used to adjust the emission intensity of the infrared emitting tube until the height L of the detected three-dimensional area is equivalent to the maximum height of the key pattern.

[0011] Furthermore, the two infrared emitting tubes separated on the left and right sides are controlled to periodically emit equal-amplitude infrared pulses with a certain time interval; in each cycle, the infrared receiving tube receives the two reflected infrared pulses, and filters out the pulses whose amplitude difference ΔV is greater than the first threshold Vn.

[0012] Furthermore, for two infrared pulses received in each cycle, if the sum of their amplitudes V1 and V2 is smaller than the second threshold Vm, they are filtered out.

[0013] Furthermore, for the two infrared pulses received in each cycle, a valid finger touch signal is identified based on the width of each pulse and the interval between the two pulses; and / or, based on the time length T4 of the reflected infrared pulse received by the infrared receiving tube, if the threshold Tn≤T4≤threshold Tm, it is determined to be a valid finger touch.

[0014] Furthermore, it also includes an infrared isolation plate, which is stacked on the side of the switch plate with the receiving tube and the transmitting tube. The infrared isolation plate has holes corresponding to the positions of each receiving tube and the transmitting tube as window holes, and the receiving tube and the transmitting tube are built into the corresponding window holes.

[0015] Furthermore, the touch surface is transparent glass; and / or the key pattern is fixed on the touch surface by inner carving or printing.

[0016] An integrated stove is also provided, comprising the above-mentioned virtual touch button based on infrared detection.

[0017] Compared with capacitive touch technology, the advantages of this utility model are:

[0018] (1) Improve the scope of application: Infrared reflection technology is not affected by non-conductive obstacles (such as gloves and water droplets), which expands the application scenarios.

[0019] (2) Enhanced anti-interference capability: Compared with capacitive touch technology, infrared reflection technology can theoretically provide better anti-electromagnetic interference performance and improve stability.

[0020] (3) Improve user experience: The non-contact sensing method reduces physical wear, extends the life of the equipment, and also reduces the frequency of cleaning and maintenance.

[0021] (4) Innovation and differentiation: As the existing capacitive touch button market is becoming saturated, proposing new technical solutions can open up new market space and attract consumers who are interested in new technologies.

[0022] Compared with traditional infrared detection technology, the advantages of this utility model are:

[0023] (1) Hardware design: The dual-transmitter and single-receiver structure forms an effective three-dimensional infrared detection area L*W*H, ensuring stable operation under various lighting conditions. At the same time, anti-interference, user experience and cost control are taken into consideration to achieve high-precision and high-reliability key switch operation;

[0024] (2) Algorithm optimization: Develop specific signal processing algorithms to accurately distinguish between real touch and environmental interference, and further improve recognition accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A front view of an integrated stove is shown;

[0026] Figure 2 The key structure of the integrated stove is shown;

[0027] Figure 3 The detection area formed by the dual-transmitting and single-receiving structure is shown;

[0028] Figure 4 A side view of the key structure is shown;

[0029] Figure 5-1 The beam radiation pattern of the 10° infrared transmitting tube is shown;

[0030] Figure 5-2 The topology of the transmitting circuit for controlling the infrared transmitting tube is shown;

[0031] Figure 6 A schematic diagram of finger touch is shown;

[0032] Figure 7 The difference in amplitude ΔV of two received pulse signals caused by the infrared received signal as the finger touches the key position is shown;

[0033] Figure 8 The infrared receiving signal waveform width and interval when the finger touches are shown;

[0034] Fig. 9 It shows the shielding of interference light from different directions when a finger touches a key. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0036] Figure 1 The front view of the integrated stove structure, the virtual touch buttons on it are as follows Figure 2-4 As shown, each touch key structure and circuit in the figure are the same. Take one of them as an example, 1 is a transparent key glass, 8 is a key pattern on the glass, i.e., a touch area, 9 is a human-machine interactive infrared switch, 2 is a PCB board, 4 and 6 are infrared transmitting tubes in the key area, 5 is an infrared receiving tube in the key area, 3 is an infrared isolation board, 10 is an infrared window hole in the isolation board, and the shaded part of 7 is an effective three-dimensional area L*W*H for infrared detection.

[0037] The touch surface on the surface of the glass 1 is arranged vertically, and a button pattern 8 is formed on the glass by inner carving or printing, which is used as a display screen. The switch plate 2 with infrared emission and reception is placed horizontally on the upper part of the glass. The switch plate partially or completely extends out of the touch surface, and a sensor component is correspondingly arranged in the extended part above each button pattern. The sensor component is a dual-transmitter and single-receiver structure. The infrared receiving tube 5 is arranged above the central axis of the button pattern 8, and the two infrared transmitting tubes 4 and 6 are symmetrically arranged on both sides of the infrared receiving tube 5. The infrared transmitting tubes 4, 6 and the receiving tube 5 are arranged in a line on one side of the touch surface and are parallel to the touch surface. The infrared rays are parallel to the glass touch surface and irradiate the other side of the glass. At this time, the light beams of the two infrared transmitting tubes on the left and right sides form a detection area. Figure 3 and Figure 4 The shaded three-dimensional area L*W*H in FIG. 7. The height L and width W of the detection three-dimensional area are respectively equivalent to the maximum height and maximum width of the key pattern. The maximum detection distance H of the detection three-dimensional area from the touch surface is between 4-9.8 mm, and the most preferred distance in this embodiment is 4 mm.

[0038] One of the technical innovations of the utility model is to use a dual-transmitter and single-receiver structure with parallel touch surfaces to form an effective reflective cube area in front of the touch area of ​​the transparent glass, with a width W being the width of the key pattern, a length L being the height of the touch key pattern, and a maximum detection distance H being 4-9.8 mm from the glass touch surface, so as to form a simulated operation of the touch key.

[0039] The implementation and advantages of the cube area are explained as follows.

[0040] Detection width control: an infrared receiving tube 5 is arranged above the central axis of the key pattern, and two infrared emitting tubes 4 and 6 are symmetrically arranged on both sides of the infrared receiving tube. The purpose of this is to make the infrared rays symmetrically and evenly distributed around the touch key axis. At the same time, an infrared emitting tube with an emission angle between 5° and 15° is selected. In this embodiment, 10° is the most preferred. For example, the radiation of a 10° infrared emitting tube is as follows: Figure 5-1 The light beam forms a nearly elliptical shape, which has the advantage of high anti-interference performance. The two symmetrical elliptical light beams overlap on the central axis of the key pattern, and the detection width of the formed cubic area can meet the requirements of covering the width of the standard glass key pattern on refrigerators and integrated stoves.

[0041] Detection distance control: The height of the cube area is controlled by controlling the intensity of infrared emission, such as Figure 5-2 , an adjustable current source is set, and the adjustable current source is coupled with the infrared emitting tube to adjust the emission intensity of the infrared emitting tube. According to the infrared reflection intensity of the touching finger, the adjustable current source is adjusted to adjust the infrared emission current, and the intensity of the infrared emission is controlled until the height L of the detection three-dimensional area is equivalent to the maximum height of the key pattern.

[0042] Control of the distance between infrared ray and glass: Based on the 10° transmitting tube, the infrared ray is emitted vertically downward, the normal of the infrared transmitting tube and the receiving tube arrangement is parallel to the glass touch surface, and the distance h between the two infrared transmitting tubes and the glass touch surface is controlled between 2-8mm, so that the detection distance H from the glass touch surface can be controlled to about 4-9.8mm. As the most preferred, h is 2mm, so that the detection distance H from the glass touch surface can be controlled to about 4mm.

[0043] In the present invention, an infrared transmitting tube with an emission angle between 5° and 15° is selected, the purpose is to transmit infrared rays into the detection area as much as possible, and effectively improve the signal-to-noise ratio of the infrared receiver. At the same time, by symmetrically arranging two infrared transmitting tubes on both sides of the infrared receiving tube, the infrared detection area can be controlled. The size of the detection area is inversely correlated with the anti-interference. The dual-emitting structure is used to ensure that the width of the detection area meets the requirements and avoids the switch precision defect caused by excessive height. The maximum detection distance H is between 4-9.8mm to achieve a balance between production error, anti-interference, and user experience. The smaller the detection thickness, the stronger the anti-interference ability. At the same time, the higher the production accuracy is required, the production cost increases exponentially. The larger the thickness, the weaker the anti-interference, and the lower the sensitivity of the touch control, which affects the user experience. For example, the finger has responded before touching, resulting in a sense of confusion of the device. The detection thickness H is set to 4-9.8mm. After entering the detection area, the finger can smoothly touch the glass surface, forming a touch-triggered switch response experience, and at the same time achieve high anti-interference performance under the permission of traditional production errors.

[0044] As another improvement scheme, the anti-interference performance is further improved through algorithm optimization, including: controlling the two infrared transmitting tubes separated on the left and right sides to periodically emit equal-amplitude infrared pulses with a certain time interval; in each cycle, the infrared receiving tube receives the two reflected infrared pulses, and filters out the pulses whose amplitude difference ΔV is greater than the first threshold Vn.

[0045] Figure 6 The figure shows the finger touch diagram. Figure 7 This is the infrared receiving signal waveform. Figure 6 As shown in the figure, T is the center line of the key, which is also the normal line of the infrared transmitting tube and receiving tube arrangement. Figure 5-2 In the transmitting circuit shown in FIG. 1 , transmitting tubes 4 and 6 successively transmit infrared pulses of equal amplitude with a certain time interval, and the infrared receiving waveform is as follows: Figure 7As shown in the figures: Figures X, Y, and Z are the output waveform diagrams of the received signals of the receiving tube when the finger touches the button. Among them, Figure X is the received waveform when the finger touches the center line T: when the finger touches the center line T of the button, the intensity of the infrared ray reflected by the finger is symmetric about the center line T, so the received signal waveform is two pulse waves with equal amplitudes. Figure Y is the output waveform diagram when the finger touch area deviates from the center line T and moves in the B direction: when the finger touch area deviates from the center line T and moves in the B direction, the intensity of the infrared ray reflected by the finger is strong for the 4th emitter signal and weak for the 6th emitter signal, so the received signal waveform is a pulse wave with a strong left and a weak right with a difference of ΔV. Figure Z is the output waveform diagram when the finger touch area deviates from the center line T and moves in the C direction: when the finger touch area deviates from the center line T and moves in the C direction, the intensity of the infrared ray reflected by the finger is strong for the 6th emitter signal and weak for the 4th emitter signal, so the received signal waveform is a pulse wave with a weak left and a strong right with a difference of ΔV. Since the farther the finger touch area deviates from the button center line T, the greater the amplitude difference ΔV between the two received pulse signals of the infrared ray received signal. Based on the characteristics of the cooperation between the pulse under the double-emitter single-receiver structure and the finger touch, set ΔV≤Vn as the effective range. On the one hand, limit the size of the finger button touch area deviating from the center line T, that is, the size of W in the shadow, through the algorithm, to achieve physical general control + algorithm precise control. On the other hand, based on the characteristics of the finger reflecting infrared rays, most of the interference can be isolated to achieve accurate recognition of finger touch.

[0046] Furthermore, for the two infrared pulses received in each cycle, if the sum of their amplitudes V1 and V2 is less than the second threshold Vm, then filter them out. When the finger moves in the L direction of the touch shadow area, the farther the finger is from the receiving tube, the smaller the amplitudes of the two received pulse waveforms will be simultaneously. By setting V1 + V2 < Vm, interference terms can be further removed, and at the same time, the distance L of the finger touch area away from the infrared receiving tube can be accurately limited. Above, Vn is the first threshold, which is adjusted according to the infrared reflection pulse of the finger under the double-emitter single-receiver structure; Vm is the second threshold, which is adjusted according to the maximum distance allowed to be away from the infrared receiving tube.

[0047] Furthermore, for the two infrared pulses received in each cycle, based on the width of each pulse and the interval between the two pulses, identify the effective finger touch signal; and / or, based on the time length T4 of the reflected infrared pulse received by the infrared receiving tube, if the threshold Tn ≤ T4 ≤ threshold Tm, then determine it as an effective finger touch. As Figure 8 shown, by judging the width T1, T3 and time interval T2 of each received signal, the effective finger touch signal can be identified, and by detecting the time length T4 of the effective signal, when Tn ≤ T4 ≤ Tm, it is determined as the effective finger touch signal of the finger, which can further filter the interference light and improve the anti-interference ability of the system.

[0048] As another improvement scheme, as Figure 3 and Fig. 9 As shown, an infrared isolation plate 3 is provided, and the infrared isolation plate 3 is stacked on the side of the switch plate 2 having the receiving tube and the transmitting tube. The infrared isolation plate 3 has holes corresponding to the positions of each receiving tube and the transmitting tube as window holes 10, and the receiving tube and the transmitting tube are built into the corresponding window holes 10.

[0049] The setting of double transmitting tubes and single receiving tube, together with the setting of the window hole in the isolation plate, can greatly improve the anti-interference ability of infrared rays:

[0050] First, since the touch key area is limited to the area of ​​the key pattern by using a dual transmitting tube and a single receiving tube, if there is interference light N1 directly irradiated into the infrared window hole, since the interference light N1 and the infrared receiving tube are in a straight line when the finger touches the key, the interference light N1 is shielded by the finger, and the finger will only reflect the signals of the transmitting tube 4 and the transmitting tube 6, thereby reliably detecting the finger touch. If there is oblique interference light N2 irradiated toward the infrared window, since the window hole of the isolation plate has a certain depth, the oblique light will not directly irradiate the receiving tube, and at most it is the infrared light diffusely reflected by the hole wall of the window. Then, when a finger touches the key area, the infrared signal reflected by the transmitting tube 4 and the transmitting tube 6 is much stronger than the signal of the oblique interference light N2, and the signal-to-noise ratio of the signal is very high, and the touch signal can also be effectively detected. In addition, the setting of the window hole can also play a good shielding role for the infrared interference emitted laterally between the dual transmitting tubes.

[0051] The virtual sensing touch key of the utility model is based on the infrared reflection principle, which overcomes the limitations of the existing capacitive touch technology, provides a more flexible, reliable and adaptable new input solution, and meets the market's continuous pursuit of advanced human-computer interaction technology. The virtual sensing touch key is applied to the integrated stove, and the transmitting tube and the receiving tube are set downward to avoid the accumulation of oil and dirt affecting the detection. In the experiment, the interference of oil smoke on the detection is almost negligible. At the same time, there is no device when viewed from the front, so it is visually hidden. The virtual touch key of the utility model can also be applied to the range hood.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.

Claims

1. A virtual touch button based on infrared detection, characterized in that: A touch surface is provided vertically, and at least one key pattern is provided on the touch surface; A switch plate is horizontally placed on the upper part of the touch surface, the switch plate partially or completely extends out of the touch surface, and a sensor component is correspondingly arranged above each of the key patterns in the extended part; Each of the sensing components includes at least one infrared receiving tube arranged above the central axis of the key pattern, and two infrared transmitting tubes symmetrically arranged on both sides of the infrared receiving tube, the infrared transmitting tube and the infrared receiving tube are arranged in a row parallel to the touch surface, and the two infrared transmitting tubes separated on the left and right sides are configured to emit light beams to jointly form a L*W*H infrared detection three-dimensional area, wherein the height L and width W of the detection three-dimensional area are respectively equivalent to the maximum height and maximum width of the key pattern, and the farthest detection distance H of the detection three-dimensional area from the touch surface is between 4-9.8mm.

2. The virtual touch button according to claim 1, characterized in that: The emission angle of the infrared emitting tube is between 5° and 15°, the emission normal is parallel to the touch surface, and the distance between the two infrared emitting tubes and the touch surface is controlled between 2 mm and 8 mm.

3. The virtual touch button according to claim 2, characterized in that: The farthest detection distance H is configured to be 4 mm, the emission angle of the infrared emitting tube is configured to be 10°, and the infrared emitting tube is 2 mm away from the touch surface.

4. The virtual touch key according to claim 2, characterized in that: It also includes an adjustable current source, which is coupled to the infrared emitting tube and is used to adjust the emission intensity of the infrared emitting tube until the height L of the detection three-dimensional area is equivalent to the maximum height of the key pattern.

5. The virtual touch button according to claim 1, characterized in that: It also includes an infrared isolation plate, which is stacked on the side of the switch plate with the receiving tube and the transmitting tube. The infrared isolation plate has holes corresponding to the positions of each receiving tube and the transmitting tube as window holes, and the receiving tube and the transmitting tube are built into the corresponding window holes.

6. The virtual touch key according to claim 1, characterized in that: The touch surface is transparent glass; And / or the key pattern is fixed on the touch surface by inner engraving or printing.

7. An integrated stove, characterized in that: Including the virtual touch button based on infrared detection as described in any one of claims 1-6.

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