Key stroke detection scheme applied to optical axis keyboard

Abstract

The invention provides a key stroke detection scheme applied to an optical axis keyboard, which is characterized in that a light emitter and a light receiver are placed on a keyboard PCB (Printed Circuit Board) by utilizing a principle that light propagation intensity is inversely proportional to a light propagation distance, a light reflecting plate is placed in a key, and a light source emitted by the light emitter is reflected to the light receiver through the light reflecting plate by utilizing light reflection; the reflecting plate can move up and down along with pressing of the key, so that the distance between the reflecting plate and the light emitter and the light receiver is changed, the intensity of light received by the light receiver is changed, and the pressing position of the optical axis key can be detected.

Description

Technical Field

[0001] The invention patent relates to a key stroke detection solution for optical axis keyboards. Background Art

[0002] The current optical axis keyboard market is highly competitive and requires detection of the specific position of keys. The present invention aims to provide a new optical axis key stroke detection solution that is low-cost and easy to implement. Summary of the invention

[0003] The purpose of the present invention is to provide an optical axis key travel detection solution, which utilizes the principle that light propagation intensity is inversely proportional to light propagation distance and adopts light reflection. A light emitter and a light receiver are placed on a keyboard PCB board, and a reflector is placed in the key. The reflector moves up and down as the key is pressed, thereby changing the distance from the light emitter and the light receiver, thereby changing the intensity of light received by the light receiver, so that the pressed position of the optical axis key can be detected.

[0004] The embodiment of the present invention is a key stroke detection scheme for an optical axis keyboard, and has the following characteristics: The optical axis keyboard key travel detection solution places the light transmitter and light receiver on the keyboard PCB board, and the reflector is placed in the key. The reflector moves up and down as the key is pressed; The light emitter may be an infrared light source, a laser, or other light sources; The optical receiver may be a phototransistor PT, a photodiode PD, a laser receiver, or other optical receivers; The reflector can be flat or curved; There may be one or more communication lines between the optical transmitter and the optical receiver and the MCU controller, and the transmitted signal may be a digital signal or an analog signal, or partly a digital signal and partly an analog signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The above and other features, properties and advantages of the present invention will become more apparent through the following description of the embodiments in conjunction with the accompanying drawings, in which the same reference numerals always represent the same features, wherein: Figure 1 A system block diagram showing the present invention applied to an optical axis keyboard key stroke detection solution;

[0006] 100 —— A key stroke detection scheme for an optical axis keyboard according to the present invention; 101 —— MCU controller; 102 – reflector; 103 —— Optical transmitter; 104 —— Optical receiver. DETAILED DESCRIPTION

[0007] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0008] Embodiments of the present invention will now be described with reference to the accompanying drawings in detail. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used in all drawings to represent the same or similar parts. In addition, although the terms used in the present invention are selected from well-known and commonly used terms, some of the terms mentioned in the specification of the present invention may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description herein. In addition, it is required to understand the present invention not only by the actual terms used, but also by the meaning implied by each term.

[0009] like Figure 1 As shown, the present invention utilizes the principle that the intensity of light propagation is inversely proportional to the distance of light propagation, adopts light reflection, places the light emitter and the light receiver on the keyboard PCB board, and places the reflector in the key. The reflector moves up and down as the key is pressed, thereby changing the distance from the light emitter and the light receiver, thereby changing the intensity of light received by the light receiver, so that the pressing position of the optical axis key can be detected.

[0010] For ease of understanding, we assume that the optical receiver converts light intensity into a voltage signal, and the voltage amplitude is proportional to the light intensity. Since light intensity is inversely proportional to propagation distance, the longer the propagation distance, the weaker the light intensity; conversely, the closer the propagation distance, the stronger the light intensity. Assume that when the key is not pressed initially: light transmitter => reflector => light receiver, light propagation distance d1, at this time the light propagation distance is the farthest, the light intensity is the weakest, and the output voltage is the minimum value Vmin.

[0011] As the button is pressed down, the light propagation distance will gradually decrease. When the button is pressed to the bottom, the light propagation distance is the shortest, and the light intensity received by the optical receiver is the largest. At this time, the output voltage of the optical receiver is the maximum value Vmax.

[0012] After the voltage signal output by the optical receiver is quantized by the MCU controller, the position of the button press can be detected.

[0013] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A key stroke detection scheme for an optical axis keyboard, characterized in that: The optical axis keyboard key travel detection solution places the light transmitter and the light receiver on the keyboard PCB board, and places a reflector in the key, and the reflector moves up and down as the key is pressed.

2. The key stroke detection scheme for an optical axis keyboard as claimed in claim 1, characterized in that: The light emitter may be an infrared light source, a laser, or other light sources.

3. The key stroke detection scheme for optical axis keyboard as claimed in claim 1, characterized in that: The optical receiver may be a phototransistor PT, a photodiode PD, a laser receiver, or other optical receivers.

4. The key stroke detection scheme for an optical axis keyboard as claimed in claim 1, characterized in that: The reflector can be flat or curved.

5. The key stroke detection scheme for optical axis keyboard as claimed in claim 1, characterized in that: There may be one or more communication lines between the optical transmitter and the optical receiver and the MCU controller, and the transmitted signal may be a digital signal or an analog signal, or partly a digital signal and partly an analog signal.

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