Backlit meter counter
By employing the principle of total internal reflection and LED backlight control in the meter counter, the problems of difficulty in reading data in dark environments and reflection from supplementary lighting have been solved, achieving efficient and low-power backlight control and improving the image quality of camera-based meter reading.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JINAN ISVCN INFORMATION TECH CO LTD
- Filing Date
- 2023-01-26
- Publication Date
- 2026-06-19
AI Technical Summary
Existing meter counters are difficult to read in dark or confined environments. The glare from the supplementary light of the camera meter reading data acquisition device affects image quality, and the backlight consumes a lot of power and there is no convenient electrical interface to control the backlight switch.
The backlit meter counter is designed using the principle of total internal reflection. The reflective surface of the transparent plastic character wheel evenly scatters light onto the character surface. The backlight switch is controlled by LED lights and reed switches. The battery is powered and sealed inside the counter housing, providing a convenient electrical interface.
It improves the image clarity of the camera meter reading, reduces power consumption, provides a convenient backlight control interface, and ensures reliable reading of counter data in dark environments.
Smart Images
Figure CN116678463B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of measuring instruments, and in particular to a backlit measuring instrument counter. Background Technology
[0002] Currently, most water and gas meter counters lack built-in backlighting. Therefore, camera-based meter reading devices used for data collection are typically equipped with supplementary lights. However, the transparent plastic or glass dials are prone to glare, which severely impacts the success rate of camera-based meter reading. For example, Chinese invention patent application CN115294330A states: "During the process of shooting with a camera, ... the glare phenomenon is very serious, directly reducing image quality and making it very difficult to detect and identify relevant parameters of the dial." Just like when we take pictures of the dial with a mobile phone, we need to be at a distance and avoid the flash or external light reflecting off the dial to capture a clear image. However, camera-based meter reading devices are generally fixed directly above the counter, and the supplementary light inside the device is difficult to position properly due to the limited space of the device's structure. Often, after adjusting the position of the supplementary light to reduce glare, the image captured is either uneven in brightness or the characters are in shadow due to the counter's structure, greatly hindering camera-based meter reading. When a meter is in a dark, confined space or when the water meter is submerged in water, manual meter reading becomes difficult. Chinese utility model patent CN209470743U discloses a natural gas meter that is easy to observe, requiring "several LED beads" to be lit simultaneously. Clearly, using multiple LED beads in a battery-powered application environment results in high power consumption, and there is no interface for a camera-based meter reader to control the backlight switch. Chinese utility model patent CN207408460U discloses a novel mechanical energy meter counter, with "10 cavities arranged in a circular pattern inside the digit wheel, each cavity corresponding to a number, and each cavity equipped with a backlight." The number of backlights needed to be lit simultaneously for each digit wheel results in high power consumption, and a camera-based meter reader cannot easily control the backlight switch. Summary of the Invention
[0003] To overcome the shortcomings of existing technologies, such as the reflection of the supplementary light of the camera meter reader affecting the quality of the counter photos taken by the camera, high backlight power consumption, lack of a backlight switch electrical interface that is convenient for both the camera meter reader and manual control, and difficulty in reading the meter in dark, narrow, or water-damaged environments, this invention provides a meter counter with backlight.
[0004] The technical solution adopted by this invention to solve its technical problem is as follows: a backlit meter counter, comprising several transparent plastic digit wheels mounted side by side on the digit wheel shaft, each digit wheel having a total reflective surface surrounding the shaft, the reflective surface reflecting the light along the axial direction of the digit wheel onto the semi-transparent digit wheel character surface to form a character backlight, the scattered light from the digit wheel illuminating the scale plate to provide backlight for the scale mark layer; a light-emitting lamp is arranged at the axial end face of the digit wheel array, a reed switch is arranged near the dial surface as an electrical control interface for controlling the backlight switch, connected to a field-effect transistor as a switching current amplifier, a low self-discharge rate battery is used to power the backlight system, and the counter components and backlight circuit are all sealed inside the counter housing.
[0005] In the aforementioned backlit meter counter, the inner reflective surface of the digit wheel is a conical surface that surrounds the axis of rotation at a 45-degree angle to the axis. Light rays parallel to the axis of rotation undergo total internal reflection on the reflective surface. Digit wheels with reflective surfaces in the same direction are located side by side at one end of the axis of rotation. The vertical projections of all reflective surfaces in the same direction on the end face of the digit wheel array do not overlap. The non-reflective area of the digit wheel through which axial light is emitted is a plane perpendicular to the axis of rotation.
[0006] In the aforementioned backlit meter counter, the emitted light from the lamp is collimated by a focusing lens and then illuminates the end face of the digit wheel array in an orientation parallel to the rotating axis and close to the observation window. The illuminating light undergoes total internal reflection upon reaching the reflective surface of the digit wheel. The conical reflective surface uniformly scatters the light onto the digit wheel's character surface. Light not illuminating the reflective surface travels through the digit wheel's planar area to the next digit wheel, undergoing reflection and direct illumination sequentially until reaching the end of a digit wheel with a unidirectional reflective surface. The reflective surfaces of multiple digit wheels act as beam splitters, scattering the light from the lamp more uniformly. The scale plate uses a light-guiding material, and a semi-transparent scale mark layer is printed on its surface. The transition area between the digit wheel array area and the pointer area of the scale plate does not have a scale mark layer printed on it, allowing the light scattered by the digit wheels to pass through this area into the pointer cavity area. The portion of the pointer area near the transition area has a thicker, sloping scale plate light-entry area, facilitating the entry of the scattered light from the digit wheels into the scale plate to provide backlighting for the scale mark layer in the pointer area.
[0007] When the number of digit wheels is too large or when there are decimal digit wheels that need to be backlit, the aforementioned backlit meter counter uses two LEDs to illuminate from both ends of the digit array. The reflective surfaces of one digit wheel and the other digit wheel are perpendicular to each other on the same axial azimuth angle. The two sets can use LEDs of different colors. When the number of digit wheels is small, only one LED can be used to illuminate from one end.
[0008] The backlit meter counter mentioned above uses LED lights as its light source. The reed switch is positioned close to the dial surface for easy access by a camera or manual intervention. The reed switch position and function are precisely marked on the scale marking layer. The battery is a disposable lithium battery with a low self-discharge rate.
[0009] The aforementioned backlit meter counter, when using a camera meter reading device to read meters, has an electromagnet positioned near the reed switch. When taking a picture to read the meter, the electromagnet is energized, illuminating the backlight. After taking the picture, the electromagnet is de-energized, and the backlight turns off. When reading meters manually, the backlight is illuminated by bringing a magnetic rod close to the reed switch position.
[0010] The aforementioned backlit meter counter has all components sealed inside the counter housing, which contains silica gel columnar desiccant. The counter housing has an IP68 protection rating.
[0011] The beneficial effects of this invention are: when using a camera meter reading device, there is no need for a built-in supplementary light. Without the reflection of the supplementary light, the clarity of the image captured on the counter is improved. Up to two lights can be used to illuminate the entire counter panel. In particular, it can ensure the clarity of the image of the character wheel array area that the camera meter reading device needs to identify most, and reduces power consumption. It has an electrical interface that can be controlled by the camera meter reading device, and the backlight can also be easily controlled manually. Attached Figure Description
[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0013] Figure 1 This is a schematic diagram of the optical path of the character wheel array of the present invention.
[0014] Figure 2 This is a schematic diagram of the scattering optical path of the present invention.
[0015] Figure 3 This is a backlight control circuit diagram of the present invention.
[0016] In the diagram: 1. Number wheel, 2. Illuminating lamp, 3. Dimming lens, 4. Scale plate, 5. Scale mark layer, 6. Reflective surface, 7. Number wheel character surface, 8. Dial surface, 9. Reed switch, 10. Rotating shaft, 11. Illuminating lamp illumination area, 12. Transparent transition area, 13. Pointer, 14. Pointer cavity area, 15. Scale plate light-receiving area. Detailed Implementation
[0017] This invention mainly utilizes the principle of total internal reflection in optics, that is, when light enters a low-density medium from a high-density medium, total internal reflection will occur when the angle of incidence is greater than the critical angle. The letter wheel (1) is made of transparent polycarbonate plastic, and the critical angle of polycarbonate is about 41 degrees. Figure 1As shown, the angle between the reflective surface (6) of the character wheel (1) and the rotating shaft (10) is 45 degrees. The incident light parallel to the rotating shaft (10) can undergo total internal reflection on the reflective surface (6). The reflective surface (6) is a conical surface surrounding the rotating shaft, which can uniformly scatter the incident light circumferentially onto the semi-transparent character wheel character surface (7).
[0018] The meter counter contains multiple digit wheels (1) mounted side by side on a rotating shaft (10). Each digit wheel (1) has a reflective surface (6) surrounding the rotating shaft (10). The digit wheels (1) with the same reflective surface (6) are located side by side at one end of the rotating shaft (10). The vertical projections of all the same reflective surfaces (6) on the end face of the digit wheel array do not overlap. The non-reflective area of the digit wheel (1) through which the axial light is emitted is a plane perpendicular to the rotating shaft (10).
[0019] LED lights (2) are arranged at both ends of the character wheel array. The light emitted by the lights (2) is collimated and adjusted by the lens (3) and then shines parallel to the rotating shaft (10) onto the light-illuminated area (11) of the character wheel array. The light is reflected by the reflective surface (6) and undergoes total internal reflection. The cone-shaped reflective surface (6) evenly scatters the light onto the character wheel code surface (7). The light that does not shine on the reflective surface (6) passes through the plane of the character wheel (1) and reaches the next character wheel (1), and is reflected and directly incident in sequence until the end of the character wheel (1) with the same reflective surface (6). The reflective surface (6) of multiple character wheels (1) is equivalent to a beam splitter, which simultaneously splits and scatters the light emitted by the lights (2), so that the character wheel code surface (7) of each character wheel (1) at the observation window has good backlight. The scale plate (4) uses a light-guiding material, and a scale mark layer (5) is printed on the surface of the scale plate (4). The scale mark layer (5) is not printed in the transparent transition area (12) between the character wheel array area and the pointer area of the scale plate (4), such as... Figure 2 As shown, the scattered light can pass through this area into the pointer cavity area (14) to illuminate the pointer (13). The part of the pointer area scale plate (4) near the transition area (12) has a thicker scale plate light-entry area (15), which facilitates the light to enter the scale plate (4) to provide backlight for the pointer area scale mark layer (5).
[0020] A reed switch (9) is arranged near the dial surface (8) as the electrical control interface for controlling the backlight switch. The reed switch (9) is arranged near the dial surface (8) and in a position that is convenient for the camera or manual connection. The precise position and function markings are made on the dial surface (8), such as... Figure 3As shown, a field-effect transistor is used as a switching current amplifier. The battery is a low-self-discharge lithium-ion battery ER14250H with a capacity of 1200mAh, a diameter of 14mm, and a height of 25mm. The maximum current when the two LEDs are lit is 3.6mA. Each data collection session of the video meter reading device is less than 1 second, and the normal collection interval is 1 hour. Without considering battery self-discharge, the usage time is: ((1200mAh ÷ (3.6mA ÷ 60s ÷ 60m)) ÷ 24h) ÷ 365d = 136.9 years. The battery's self-discharge rate is less than 1.5% per year. Comparison shows that the main energy consumption is due to battery self-discharge. Therefore, this lithium battery can guarantee the use of the backlight system for video meter reading for more than 30 years. The battery is small and can be integrated into the counter housing. All components and circuits are sealed inside the counter housing, which contains silica gel columnar desiccant. The counter housing has an IP68 protection rating.
[0021] When using a camera meter reader, an electromagnet is set up near the reed switch (9) of the camera meter reader. When taking a picture to read the meter, the electromagnet is energized and the backlight is lit. After taking the picture, the electromagnet is de-energized and the backlight is turned off. When reading the meter manually, the backlight will be lit when a magnetic rod is brought close to the position marked on the reed switch (9) of the meter face (8).
Claims
1. A backlit meter counter comprising several transparent plastic digit wheels mounted side-by-side on a digit wheel axle. Each digit wheel has a total reflective surface surrounding the axle. The reflective surface reflects axial light from the digit wheel onto a semi-transparent digit wheel character surface to form a character backlight. The scattered light from the digit wheels illuminates a scale plate, providing backlight for the scale marking layer. The inner reflective surface of the digit wheel is a conical surface at a 45-degree angle to the axle. Light parallel to the axle undergoes total internal reflection on the reflective surface. Digit wheels with reflective surfaces in the same direction are located side-by-side at one end of the axle. The vertical projections of all reflective surfaces in the same direction onto the end face of the digit wheel array do not overlap. The non-reflective area of the digit wheel through which axial light is emitted is a plane perpendicular to the axle. A light source is placed at the axial end face of the character wheel array. The light emitted by the light source is collimated and adjusted by a lens, and then shines on the end face of the character wheel array in an direction parallel to the rotation axis and close to the observation window. After the light reaches the reflective surface, it undergoes total internal reflection. The conical reflective surface evenly scatters the light onto the character wheel character surface. The light that does not hit the reflective surface reaches the next character wheel through the character wheel plane area, and is reflected and directly incident in sequence until the end of the character wheel with a reflective surface in the same direction. The reflective surfaces of multiple character wheels are equivalent to beam splitters, which scatter the light from the light source in a relatively uniform manner. The scale plate uses light-guiding material, and a semi-transparent scale mark layer is printed on the surface of the scale plate. The transition area between the character wheel array area and the pointer area of the scale plate is not printed with a scale mark layer. The light scattered by the character wheel passes through this area and enters the pointer cavity area. The part of the pointer area of the scale plate near the transition area has a scale plate light-entry area with a set thickness slope, which facilitates the entry of the scattered light from the character wheel into the scale plate to provide backlight for the scale mark layer of the pointer area. A reed switch is placed near the dial as the electrical control interface for controlling the backlight switch. A battery with a low self-discharge rate is used to power the backlight system. The counter components and the backlight circuit are all sealed inside the counter housing.
2. The backlit meter counter according to claim 1, characterized in that: When there are too many character wheels or when there are decimal character wheels that need to be backlit, two lights are used to illuminate from both ends of the character array. The reflective surfaces of one character wheel and the reflective surfaces of the other character wheel are perpendicular to each other on the same axial azimuth angle. Two sets of lights of different colors are used. When the number of character wheels is less than the set number, only one light is used to illuminate from one end.
3. The backlit meter counter according to claim 1, characterized in that: The reed switches are positioned close to the dial surface for easy access by the camera or manual intervention. Precise location and function markings for the reed switches are made on the scale marking layer. The battery is a low-self-discharge disposable lithium battery. When using a camera-based meter reader, an electromagnet is placed near the reed switch location markings. The electromagnet is energized during meter reading, illuminating the backlight; after the photo is taken, the electromagnet is de-energized, and the backlight turns off. For manual meter reading, a magnetic rod is brought near the reed switch location markings to illuminate the backlight. All components are sealed within the counter housing, which contains silica gel desiccant columns. The counter housing has an IP68 protection rating.