High-precision transparent electric heating glass for bacterial culture

Abstract

The utility model discloses a high-precision transparent electric heating glass for bacterial culture belongs to biological experiment equipment technical field. It includes from top to bottom the heating function layer, electrode connecting layer and apron, forms three layer composite structure. Heating function layer contains glass substrate and ITO transparent conductive film, and apron is high -aluminum toughened glass, and is pasted through OCA optical glue, and total thickness is less than 0.8mm. Glass substrate is surrounded with black ink silk screen frame and forms work area, and ITO film square resistance is 7-10 ohm / , and copper electrode strip connects external power supply. The visible light transmittance of glass substrate and apron is greater than or equal to 85%, and the light transmittance of composite structure is greater than or equal to 80%. It has high-precision temperature control, fast heating, transparent observation, low pollution and other advantages, solves traditional culture ware temperature control extensive, and observes limited and pollution problem, is applicable to the bacterial culture and biological experiment scene of needing accurate temperature control and real -time observation.

Description

Technical Field

[0001] This utility model relates to the field of biological experimental equipment technology, specifically to a high-precision transparent electrically heated glass for bacterial culture, and more particularly to the application of ITO transparent conductive glass in the field of biological culture, which is suitable for bacterial culture and biological experimental scenarios that require precise temperature control and real-time observation. Background Technology

[0002] In biomedical research, microbiology experiments, and pharmaceutical fields, bacterial culture is a fundamental and crucial technique. Bacterial growth and reproduction are extremely sensitive to environmental conditions, especially parameters such as temperature, humidity, and cleanliness, which require strict control. Traditional bacterial culture equipment generally suffers from the following technical bottlenecks:

[0003] I. Insufficient temperature control precision

[0004] Most existing culture vessels use external heating elements such as heating wires and heating plates to heat the culture environment through heat conduction. This heating method has significant drawbacks: firstly, there is a heat conduction lag between the heating element and the culture area, resulting in a slow temperature response, typically requiring several minutes or even longer to reach the set temperature; secondly, uneven heat distribution is a prominent problem, with temperature deviations in different areas of the culture vessel reaching ±2℃ or more, making it difficult to meet the requirements of precise experiments for a constant temperature environment (such as the culture of certain thermophilic bacteria, which requires accuracy within ±0.5℃).

[0005] II. Limited Visual Observation

[0006] Traditional culture vessels, designed for heating, often use opaque or semi-transparent materials (such as ceramic or metal substrates), or opaque heating wires laid on transparent substrates. This prevents researchers from directly observing the dynamic growth changes of bacteria during heating under a microscope. While some devices use transparent materials, the heating element may obstruct the view, or the material's light transmittance may be low (usually below 70%), making high-resolution real-time microscopic observation difficult and limiting the study of the entire bacterial growth cycle.

[0007] III. High risk of pollution

[0008] Traditional heating elements (such as metal heating wires) are prone to oxidation and corrosion during long-term use, producing metal ions or debris that may contaminate the culture environment and affect the purity of bacterial growth. Furthermore, the non-integrated heating structure results in numerous gaps and dead corners in the culture vessels, making thorough cleaning difficult and further increasing the risk of cross-contamination.

[0009] IV. Complex structure and high energy consumption

[0010] Existing equipment typically requires additional heating modules, temperature sensors, and control systems, resulting in a complex and bulky overall structure that occupies a significant amount of laboratory space. Furthermore, external heating elements have low thermal efficiency and significant energy loss, leading to unnecessary energy waste.

[0011] To address the aforementioned issues, those skilled in the art have attempted to apply transparent conductive materials to the heating of culture vessels. Among these, ITO (indium tin oxide) transparent conductive glass, due to its high light transmittance (visible light transmittance can reach over 85%), uniform electrothermal properties, and good chemical stability, has become an ideal heating substrate. However, existing heating devices based on ITO glass still have the following shortcomings: high sheet resistance (typically greater than 15Ω / □), resulting in a slow heating rate (requiring more than 30 seconds to reach the set temperature); simple temperature control algorithms, unable to achieve high-precision constant temperature control at the ±0.3℃ level; and structural design not fully considering the special characteristics of biological experiments, such as the lack of clear division of the culture working area and electrode connection methods that easily interfere with microscopic observation.

[0012] Therefore, there is an urgent need to develop a transparent electrically heated glass for bacterial culture that combines high transparency, rapid heating capability, precise temperature control, and low risk of contamination, in order to meet the needs of modern biological experiments for a high-precision, visualized culture environment. Utility Model Content

[0013] The core objective of this invention is to provide a high-precision transparent electrically heated glass for bacterial culture. By optimizing the structural design and temperature control scheme of ITO conductive glass, it solves the technical problems of existing culture vessels in terms of temperature control accuracy, visual observation, and risk of contamination.

[0014] This invention provides a high-precision transparent electrically heated glass for bacterial culture, comprising a heating functional layer, an electrode connection layer, and a cover plate bonded together from top to bottom, forming a three-layer composite structure. The heating functional layer includes a glass substrate and an ITO transparent conductive film deposited on its surface. The cover plate is transparent high-alumina tempered glass, bonded to the heating functional layer with OCA optical adhesive, with a total thickness of less than 0.8 mm. The heating functional layer utilizes the Joule heating generated by the ITO transparent conductive film when energized to achieve uniform heating. The electrode connection layer connects the ITO film to an external power source, forming a current loop. The high-alumina tempered glass provides physical support and protection while ensuring light transmittance. This technical solution eliminates gaps through a G+G bonding process, avoiding bacterial contamination; the overall light transmittance is ≥80%, meeting the requirements for real-time microscopic observation; the low sheet resistance of ITO (7-10Ω / □) shortens the heating time to 5-10 seconds.

[0015] Further description of the aforementioned scheme: the upper surface of the glass substrate of the heating functional layer is provided with a screen-printed black ink border, which surrounds the heating working area and can block the electrode connection parts to avoid visual interference during optical observation.

[0016] Further description of the aforementioned scheme: the electrode connection layer includes copper electrode strips disposed on both sides of the ITO transparent conductive film, and the copper electrode strips are connected to an external DC power supply through silver-plated conductive wires.

[0017] Further description of the aforementioned scheme: the visible light transmittance of both the glass substrate and the high-aluminum tempered glass is ≥85%, and the overall light transmittance of the composite structure is ≥80%, supporting direct observation of bacterial growth dynamics using an optical microscope with magnification below 1000x.

[0018] Further description of the aforementioned scheme: the ITO transparent conductive film is prepared by vacuum magnetron sputtering process, the film thickness is 150-180nm, and the surface uniformity deviation is ≤3%.

[0019] Further description of the aforementioned solution: the edges of both the glass substrate and the high-aluminum tempered glass are CNC ground to form a rounded corner structure of R1.5-R3.0mm. This enhances the impact resistance of the tempered glass edges, reduces the risk of breakage, and prevents scratches to laboratory personnel or damage to the microscope stage.

[0020] Through the above-described technical solution, this invention significantly improves the controllability and visualization of the bacterial culture process, with the following specific beneficial effects:

[0021] (I) High-precision temperature control

[0022] The low sheet resistance (7-10Ω / □) of the ITO transparent conductive film ensures efficient output of heating power. Combined with a PID closed-loop control system, it achieves a temperature control accuracy of ±0.3℃, superior to existing technologies (above ±1℃). For example, in a 37℃ constant-temperature culture environment, traditional equipment can experience temperature fluctuations of ±1.5℃, while this device can control the fluctuations within ±0.25℃, providing an ideal environment for the stable growth of mesophilic bacteria.

[0023] (II) Fully Transparent Visual Observation

[0024] The overall structure employs double-layered ultra-thin glass (total thickness 0.73 mm) and a fully transparent ITO conductive film, with a visible light transmittance of ≥80%. The ITO conductive film layer has a uniform thickness (deviation ≤3%), avoiding the obstruction problems associated with traditional heating wires. Researchers can directly observe the morphological changes, division processes, and colony formation of bacteria under heating conditions using an optical microscope (magnification ≤1000x), providing a crucial tool for dynamic biological research.

[0025] (III) Rapid heating and energy-saving characteristics

[0026] Due to the high conductivity and low heat capacity of the ITO transparent conductive film, the glass module can complete the heating process from room temperature to 37°C within 5-10 seconds, which is more than 90% more efficient than traditional heating methods (such as hot water bath heating, which takes 3-5 minutes). At the same time, the low voltage design of the DC power supply (12V) ensures the safety of the device, and the low energy consumption (maximum power ≤5W) meets the environmental protection requirements of green laboratories.

[0027] (iv) Low pollution and high reliability

[0028] The integrated G+G bonding structure eliminates the mechanical gaps between the traditional heating element and the glass substrate, avoiding the risk of contamination caused by the infiltration of bacteria or culture medium. The chemical inertness of the ITO transparent conductive film (acid and alkali resistance pH=2-12) and the high abrasion resistance of the tempered glass (surface hardness 6H) ensure the stability of the device during long-term use, with a service life of more than 5 years, significantly reducing experimental costs. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is an overall schematic diagram of an embodiment of the present utility model;

[0031] Figure 2 An exploded view diagram provided for an embodiment of this utility model.

[0032] The following are the labeling elements in the figure:

[0033] 1. Heating functional layer; 11. Glass substrate; 12. ITO transparent conductive film; 13. Ink border; 2. Copper electrode strip; 3. Cover plate.

[0034] The accompanying drawings have illustrated specific embodiments of the present invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0036] To make the technical solution and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0037] Please see Figures 1-2 As shown, this utility model provides a high-precision transparent electrically heated glass for bacterial culture. Its core lies in constructing a three-layer composite structure device that combines efficient heating, precise temperature control, and fully transparent observation functions. Specifically, it consists of a heating functional layer 1, an electrode connection layer, and a cover plate 3, which are sequentially bonded from top to bottom. The heating functional layer 1, as the core unit, includes a glass substrate 11 and an ITO transparent conductive film 12 deposited on its surface. The glass substrate 11 is made of 0.4mm ultra-thin electronic glass with a silicon dioxide content ≥91% and a coefficient of thermal expansion of (3.3±0.1)×10⁻⁶. -6 / K forms excellent thermal matching with the ITO film, and can withstand the thermal stress generated during long-term heating without cracking. The ITO transparent conductive film 12 is prepared by vacuum magnetron sputtering. The target material adopts an In2O3:SnO2 mass ratio of 9:1. Under the conditions of vacuum degree of 5×10-3Pa and sputtering power of about 50-60KW, a film layer with a thickness of 150-180nm is formed. The sheet resistance is stable at 7-10Ω / □ and the surface uniformity deviation is ≤3%. It not only ensures the characteristics of low resistance and rapid heating, but also achieves visible light transmittance ≥85% (test wavelength range 400-760nm) through nanoscale thickness control. To clearly delineate the working area for bacterial culture and shield the interference of electrodes on observation, a high-temperature resistant black ink border 13 is screen-printed on the upper surface of the glass substrate 11. This ink uses a thermosetting epoxy resin system, with a thickness of 20-30μm after curing. It can withstand high-temperature sterilization at 150℃ and corrosion by PBS buffer. The border width is designed to be 2-3mm, and the area of ​​the enclosed rectangular working area can be customized according to experimental needs. The typical size is 50mm×50mm, which is suitable for the observation range of standard glass slides.

[0038] The electrode connection layer includes copper electrode strips 2 disposed on both sides of the ITO transparent conductive film 12. The copper electrode strips 2 are 50 μm thick and are bonded to the edge of the ITO film by conductive silver paste. The silver particles in the conductive silver paste have a particle size ≤1 μm to ensure a low contact resistance connection. The copper electrode strips 2 are 8-10 mm wide and extend 1-2 mm beyond the edge of the glass substrate 11 to facilitate the soldering of externally silver-plated conductive wires. The conductive wires have a diameter of 0.2 mm and are covered with a PTFE insulating layer that is resistant to temperatures up to 260℃. They are connected to the copper electrode strips 2 by ultrasonic welding, with a contact resistance ≤0.05Ω. To avoid interference from the electrode area to microscopic observation, the position of the copper electrode strips 2 overlaps with the ink border 13, ensuring that there are no visible metal structures in the working area during microscopic observation, thus not affecting the clear capture of bacterial growth dynamics.

[0039] The cover plate 3 is made of 0.33mm high-alumina tempered glass with an aluminum content of ≥10% and a surface hardness of 6H. Its impact resistance is more than 5 times that of ordinary glass. A surface compressive stress layer is formed through a high-temperature chemical tempering process, with specific parameters of tempering temperature 420±5℃ and tempering time 2.5~4 hours, resulting in a surface compressive stress of 600-700MPa. The visible light transmittance of the high-alumina tempered glass is ≥92%. It is bonded to ITO glass with OCA optical adhesive. The OCA adhesive is 50μm thick and has a transmittance of ≥95%. After bonding, the overall transmittance of the composite structure is ≥80%. Actual measurements show that the transmittance at a wavelength of 550nm is 83%, meeting the observation requirements of a 1000x optical microscope, which can clearly present details such as the morphological changes and division process of bacteria.

[0040] In terms of manufacturing process, the glass substrate 11 is first pretreated, including precision cutting, CNC edge grinding, high-temperature tempering, and ultrasonic cleaning. Cutting is performed using a diamond wheel cutter, with dimensional tolerances controlled within ±0.1mm and edge chipping ≤0.05mm. CNC edge grinding uses a two-axis CNC edge grinding machine to process the glass edges into rounded corners of R1.5-R3.0mm, with a grinding head speed of 35000r / min, a feed rate of 200mm / min, and a surface roughness Ra≤0.2μm, eliminating safety hazards caused by sharp angles. During high-temperature tempering, chemical strengthening is used at a tempering temperature of 420±5℃ for 2.5–4 hours, achieving a surface compressive stress of 600-700MPa. Ultrasonic cleaning employs a three-stage process: sequentially cleaning in a 1% alkaline detergent solution at 55℃, followed by deionized water, and then slow-drying for 10 minutes to ensure surface cleanliness (contaminants with particle size ≥5μm ≤3 particles / cm). 2 ).

[0041] ITO film deposition employs a vacuum magnetron sputtering process, with the cavity pre-evacuated to 1×10⁻⁶ before coating. -4At 0.5 Pa, 99.999% pure argon gas is introduced and the pressure is maintained at 0.5 Pa. The sputtering power is about 50-60 KW, and ITO is continuously vacuum coated.

[0042] During multilayer bonding, conductive silver paste is first applied to the electrode area reserved on the ITO film. After bonding the copper electrode strip 2, it is cured in an oven at 80℃ for 1 hour to ensure a bonding strength ≥5N / cm. Subsequently, a fully automatic vacuum bonding machine is used for G+G bonding. A 50±5μm thick OCA optical adhesive is used to align and bond with the high-alumina tempered glass (alignment accuracy ≤50μm). During the bonding process, the vacuum degree is maintained at -0.095MPa and the temperature at 50℃. A rolling device is used to roll the glass at a speed of 100mm / min to eliminate interlayer air bubbles (the number of air bubbles with a diameter ≥0.1mm ≤1 / cm). 2 Finally, the OCA adhesive was defoamed for 30 minutes at 80℃ and 60%RH to ensure complete cross-linking and a peel strength of over 5N / 25mm.

[0043] For temperature control, a 12V DC power supply is used, and the circuit is controlled by a solid-state relay. The heating power of the ITO film is controlled by adjusting the duty cycle of the PWM wave. The PID parameters are tuned using the critical proportional gain method, with a proportional gain of Kp = 12, an integral time of Ti = 60s, and a derivative time of Td = 15s. In actual testing at a set temperature of 37℃, the heating time is 8 seconds, the overshoot is ≤0.1℃, and the steady-state fluctuation range is ±0.25℃, which is significantly better than traditional culture equipment. Infrared thermal imaging shows that the device can heat from room temperature (25℃) to 37±0.3℃ within 10 seconds, with a temperature uniformity deviation of ≤2.5% (temperature difference between the center and edge of the working area ≤0.3℃). The heating speed and uniformity are significantly better than traditional heating wire heating methods.

[0044] In biological experiments, the device can be first sterilized by autoclaving at 121°C for 20 minutes, then cooled and disinfected with 75% ethanol. Under sterile conditions, bacterial suspension and culture medium are added dropwise to the working area, covered with agar, and placed on the microscope stage. The culture temperature is set using a temperature controller, allowing for real-time observation of bacterial growth dynamics. Taking the growth curve measurement of Bacillus subtilis as an example, the complete process from the logarithmic growth phase to the stationary phase can be clearly observed at a constant temperature of 37°C. In contrast, traditional culture dishes cause some bacteria to prematurely enter dormancy due to temperature fluctuations, making it impossible to capture the complete division dynamics. The integrated G+G bonding structure of the device eliminates gaps and avoids contamination. The ITO membrane is resistant to chemical corrosion at pH 2-12 and can be reused ≥500 times, significantly extending its service life compared to traditional metal heating wire culture dishes.

[0045] Performance tests show that the composite structure has a visible light transmittance of ≥80%, provides clear imaging under a 1000x microscope with a resolution of up to 1.0μm, has an inter-electrode line resistance of approximately 12Ω, and delivers 12W of power at 12V, demonstrating low energy consumption and safety. After 500 hours of continuous high-temperature testing, the ITO film resistance change rate is ≤2%, and the transmittance decrease is ≤3%, indicating a stable and reliable structure. Future development could involve integrating a temperature sensor array and an IoT module to improve temperature uniformity and enable remote monitoring, or adjusting substrate size and film parameters to adapt to different experimental scenarios, such as anaerobic culture and fluorescence staining experiments, showcasing broad application prospects.

[0046] Other embodiments of the present invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the foregoing claims.

[0047] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element present. Conversely, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations. The terms "upper end," "lower end," "left side," "right side," "front end," "rear end," and similar expressions used herein refer to the positional relationship with reference to the accompanying drawings.

[0048] It should be understood that this invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this invention is limited only by the appended claims.

Claims

1. A high-precision transparent electrically heated glass for bacterial culture, characterized in that, The structure consists of a heating functional layer (1), an electrode connection layer, and a cover plate (3) bonded together from top to bottom, forming a three-layer composite structure. The heating functional layer (1) includes a glass substrate (11) and an ITO transparent conductive film (12) deposited on its surface. The cover plate (3) is a transparent high-aluminum tempered glass bonded to the heating functional layer (1) by means of OCA optical adhesive.

2. The high-precision transparent electrically heated glass for bacterial culture according to claim 1, characterized in that, The upper surface of the glass substrate (11) of the heating functional layer (1) is provided with a screen-printed black ink border (13), which forms a heating working area.

3. The high-precision transparent electrically heated glass for bacterial culture according to claim 1, characterized in that, The electrode connection layer includes copper electrode strips (2) disposed on both sides of the ITO transparent conductive film (12), and the copper electrode strips (2) are connected to an external DC power supply through silver-plated conductive wires.

4. The high-precision transparent electrically heated glass for bacterial culture according to claim 1, characterized in that, The visible light transmittance of the glass substrate (11) and the high-aluminum tempered glass is ≥85%, and the overall transmittance of the composite structure is ≥80%.

5. The high-precision transparent electrically heated glass for bacterial culture according to claim 1, characterized in that, The ITO transparent conductive film (12) is prepared by vacuum magnetron sputtering process, with a film thickness of 150-180nm and a surface uniformity deviation of ≤3%.

6. The high-precision transparent electrically heated glass for bacterial culture according to claim 1, characterized in that, The edges of the glass substrate (11) and the high-aluminum tempered glass are both CNC ground to form a rounded corner structure of R1.5-R3.0mm.

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