132results about How to "Small coefficient of thermal expansion" patented technology

The invention discloses a heat-resistant ceramic edible vessel capable of being burnt over open flame and a production method thereof. A blank body of the heat-resistant ceramic edible vessel comprises kaoline, spodumene, lithium pottery stone, carbon-free silicon whiskers, bentonite, cured steatite and clay. The production method comprises the following steps that: the carbon-free silicon whiskers are dispersed by a mechanical low-speed ball-milling method, water is used as the ball milling media, the rotating speed adopted in the ball milling process is 250r/min, the weight ratio of materials to balls to water is 1/2/1.2, the ball milling time is 3 to 4 hours, the materials are dried into dry materials after ball milling completion, and the preparation method also comprises the following steps of material proportioning, ball milling through adding water, sieving, deironing, filter pressing, pugging, forming, drying, biscuiting, glazing and sintering. The product has extremely high heat resistance and mechanical strength, and the heat stability reaches the goal that, the vessel cannot be popped through once heat exchange in water with the temperature being 800 DEG C to 20 DEG C.

The invention discloses a microcrystalline glass ceramic binding agent, a preparing method thereof, an SG grinding wheel and a preparing method thereof. The binding agent is prepared from, by weight percentage, 40% to 65% of SiO2, 6% to 20% of Al2O3, 5% to 18% of Na2O, 0.5% to 5% of CaO, 3% to 10% of K2O, 8% to 35% of B2O3, 0.5% to 2% of MgO and 2% to 6% of TiO2. The microcrystalline glass ceramic binding agent is formed by reasonably selecting the raw materials, the scientific ratio is adopted, the binding agent has the beneficial effects of being low in thermal expansion coefficient and crystallization temperature and high in strength accordingly, the microcrystalline glass ceramic binding agent is suitable for being used as a binding agent of the SG grinding wheel, the firing temperature of the SG grinding wheel is greatly reduced, and the firing time of the SG grinding wheel is greatly shortened; and meanwhile the work efficiency and the machining accuracy of the SG grinding wheel are improved, grinding heat is reduced, and the service life of the grinding wheel is prolonged.

The invention discloses a high-temperature-resistant flexible transparent conducting film, and a preparation method and application thereof. The high-temperature-resistant flexible transparent conducting film comprises a high-temperature-resistant flexible transparent substrate and a transparent conducting layer deposited on the high-temperature-resistant flexible transparent substrate. The high-temperature-resistant flexible transparent conducting film can resist high temperature, and has the advantages of low thermal expansion coefficient, smooth surface, high transparency, stable photoelectric properties, simple manufacturing technique and low cost.

The invention proposes a method for preparing a fiber-reinforced silicon carbide ceramic-based composite material, which includes the following steps: using chemical vapor infiltration to deposit one or more layers of continuous interface phases on the fibers of the fiber preform; using a ceramic organic precursor solution to impregnate and deposit The fiber preform with interfacial phase; the impregnated fiber preform is cracked in a vacuum furnace to form a silicon carbide-based composite material matrix; the fiber preform with stable shape obtained in the above steps is removed from the tooling to obtain a molded body; After the body is impregnated with the organic precursor solution and dried, it is cracked in a vacuum furnace and transformed into a ceramic matrix; the above steps are repeated 6 to 8 times to obtain a relatively dense shaped body; the obtained material is further densified by chemical vapor infiltration. The above method is conducive to the preparation of fiber-reinforced ceramic matrix composite materials or components with complex shapes, and the obtained materials have good thermal shock resistance, and at the same time, the ceramic matrix has the characteristics of high bonding strength.

The invention discloses a waterborne color transparent glass paint and a preparation method thereof and relates to the glass paint industrial field. The waterborne color transparent glass paint comprises the following raw materials by weight percent: 60%-68% of waterborne epoxy emulsion, 4%-8% of waterborne amino resin, 2%-4% of cosolvent, 0.3%-0.8% of neutralizer, 15%-20% of deionized water, 5%-10% of waterborne metal complex dye, 0.5%-1.0% of waterborne silane coupling agent and 0.1%-0.4% of waterborne defoaming agent. After the waterborne color transparent glass paint prepared by the preparation method is sprayed on the surface of glass, the glass is roasted at 180-200 DEG C for 10-15min for curing and film-forming; and the paint film has bright color, high glossiness, good transparency, good water boiling resistance, high hardness and high adhesive force to glass.

There is provided a honeycomb structure and a method for producing the honeycomb structure, capable of reducing variance in pore diameter depending on part and capable of increasing the mean pore diameter as a whole. There is provided a method for producing a cordierite honeycomb structure 1 including the step of firing a honeycomb formed body. In the firing step, a temperature rise rate from 1200° C. to 1250° C. is controlled to 40° C./hr or more, a temperature rise rate from 1250° C. to 1300° C. is controlled to 2 to 40° C./hr, and a temperature rise rate from 1300° C. to 1400° C. is controlled to 40° C./hr or more. There is further provided a honeycomb structure having a porosity of 50 to 70%, a mean pore diameter of 15 to 30 μm, a difference in a mean pore diameter of 5 μm or less between in the central portion and in the outer peripheral portion, a thermal expansion coefficient of 1.0×10⁻⁶/° C. or less in each of the central portion and the outer peripheral portion, and an A-axis compression strength of 1.5 MPa or more in each of the central portion and the outer peripheral portion.

A dielectric ceramic composition includes about 10% to about 40% by weight of BaO, about 20% to about 65% by weight of SiO₂, about 6% to about 40% by weight of Al₂O₃, about 1% to about 15% by weight of B₂O₃, about 0.3% to about 3% by weight of Cr₂O₃, and about 1% to about 40% by weight of ZrO₂. A multilayer ceramic substrate has a laminated structure including an inner layer portion and outer layer portions that have a smaller thermal expansion coefficient than that of the inner layer portion. The use of the dielectric ceramic composition for the outer layer portions enables the ceramic to be resistant to erosion caused by a plating liquid used for plating external conductive films, thus maintaining good adhesiveness between the external conductive films and the outer layer portions.

The invention discloses a composite performance reinforcing agent for producing alumina silicate glass. The composite performance reinforcing agent for producing alumina silicate glass is the combination of at least two of metal oxides, including K2SO4, Na2SO4, Li2SO4, KNO3, NaNO3, LiNO3, SnO2 and Sb2O3, and two of rear-earth oxides, including La2O3, CeO2, Sm2O3, Yb2O3 and Nd2O3; the composite performance reinforcing agent is added to the basic formula of the alumina silicate glass, on one hand, the clarification performance of the alumina silicate glass in the smelting process can be enhanced, and the strength and mechanical and chemical stability are improved; on the other hand, rare-earth elements are added, so the structure of the glass body is changed, and the performance of the glass body is improved; after the composite performance reinforcing agent and the glass body are melted, and a composite effect is generated, so that the mechanical performance of the alumina silicate glass is improved, and the alumina silicate glass is enabled to have better environmental suitability.

The invention discloses a manufacturing method of a copper/diamond composite material with the high thermal conductivity and belongs to the technical field of composite materials. Alloy element titanium is added on a copper matrix, and the copper/diamond composite material is manufactured through an air-pressure infiltration method. According to the optimum manufacturing parameters, the content of alloy element titanium is 0.5 wt.%, the infiltration temperature is 1,150 DEG C, the heat preservation pressure is 1.0 MPa, and the temperature preservation time is 30 min. The thermal conductivity of the manufactured copper/diamond composite material is 752 W/mK, and the coefficient of thermal expansion is 6.5*10<-6>/K. By the adoption of the manufacturing method of the copper/diamond composite material, a good technical solution is provided for efficient heat dissipation of large-power devices.

The invention relates to a fluorine-containing flexible-rigid polyimide film, and a preparation method and application thereof. The film comprises flexible fluorine-containing aromatic diamines, aromatic dianhydride-1, rigid aromatic diamines and rigid aromatic dianhydrides. The preparation method of the film comprises the following steps: preparing a fluorine-containing flexible-rigid block polyamic acid resin solution from flexible fluorine-containing aromatic diamines, and carrying out solvent removal and imidization to finally form the polyimide film. The polyimide film can be used as an insulation film base plate material for flexible printed circuits, an insulation film base plate material for flexible photoelectric display devices and an insulation film base plate material for flexible film solar cells. The resin has low thermal expansion coefficient, low dielectric constant and low water absorptivity, and has important application value in the fields of micro-electronics, photoelectric display and the like.

A high-strength refractory ceramic filter for catalytic cleaning is composed of supporting body and surficial layer of carrier-catalytic active components. It is prepared through such steps as breaking alumina (50-70%), zircon (20-35%) and aluminium fluoride (10-15%), mixing with aqueous solution of polyvinyl alcohol, shaping supporting body, calcining, preparing solution of Al sol from AlCl2 (28-32%), absolute alcohol, water and nitric acid, adding nitrates of Mg, Cu, Mn, Co, Pd, La Si and K, reflowing, concentrating, immersing the supporting body in the solution, drying, and calcining.

The invention relates to heat resistance concrete and a preparation method thereof. The heat resistance concrete is prepared from the following raw materials comprising portland cement, coal ash, basalt with the particle size of between 20 and 40 millimeters, gravels with the continuous level of between 5 and 25, medium-coarse sand, a corrosion inhibitor, a water reducing agent, water and the like. The preparation method comprises the following steps of: selecting the raw materials; mechanically stirring for 2 to 3 minutes; after the raw materials are stirred and mixed uniformly, hierarchically pouring, wherein each layer is 25 to 30 centimeters thick; and after pouring, maintaining for at least 7 days in a damp environment with temperature of between 15 and 25 DEG C. The concrete prepared by stirring the raw materials according to the proportions has high peaceability and favorable viscosity; the performance of the mixture meets the construction requirement; the prepared concrete has the heat resistance of between 700 and 1,200 DEG C, the strength level of between C25 and C30, the high temperature strength of between 3.5 and 20 Mpa and the slumps of between 160 and 180 centimeters, can be pumped for construction, and is suitable for engineering with relatively high temperature and zero acid-base erosion.

The invention relates to a high-adhesion-property low-linear-expansion-coefficient polyimide film material and a preparation method thereof, belonging to the technical field of high polymer material synthesis. The main chain of the polyimide contains cyano group, and is a homopolymerized or copolymerized polyimide polymer of a rigid chain; and thus, the polyimide has higher adhesion property and low linear expansion coefficient. The preparation method comprises the following steps: synthesizing cyano-introduced amino monomer containing rigid structure; and carrying out polycondensation on the synthesized amino monomer or with other diamine monomers containing rigid structure and acid anhydride monomer to obtain the polyimide film. The polyimide film material has higher adhesion property and lower linear expansion coefficient, so that the adhesion property and linear expansion coefficient are optimal, and the mechanical property and heat stability of the polyimide are obviously improved. The polyimide film material can be used in field of high-adhesion-property materials and provide low linear expansion coefficient.

The invention discloses a thermosetting resin composition. The thermosetting resin composition comprises the following solid components in parts by weight: 10-60 parts of an allyl-modified bismaleimide resin prepolymer, 10-50 parts of a cyanate ester resin, 10-30 parts of an active ester, 5-25 parts of epoxy resin and 0-35 parts of an inorganic filler. The novel thermosetting resin composition disclosed by the invention contains less inorganic filler, but the novel thermosetting resin composition has low thermal expansion coefficient, can maintain high rigidity and can not be affected in excellent dielectric electrical properties. The novel thermosetting resin composition can be well applied to the field of high-density interconnected integrated-circuit packaging and the high-speed high-frequency high-performance printed circuit boards.

The invention discloses artificial nice foundry sand which comprises the following components in mass percent: 70 to 85% of Al2O3, 8 to 12% of silicon, 2% of Fe2O3, and the balance of impurities. The nice foundry sand is spherical and ranges from 10 to 180 meshes. A preparation method of the artificial nice foundry sand comprises the steps of: (1) adding bauxite to a container, and roasting into molten liquid; and (2) applying air pressure at 10m/s while the molten liquid of the bauxite flows out from the container, thus obtaining the nice foundry sand. The nice foundry sand is low in price, environment-friendly, resistant to high temperature, low in thermal expansion rate and high in recycling function, and can be widely applied to the casting industry.

The invention provides optical glass which comprises, in weight percent, 41-58% of SiO2, 18-32% of TiO2, 3-18% of Na2O, 2-15% of K2O and 2-15% of BaO, wherein Na2O/(Na2O+K2O) is 0.3-0.85. By the aid of reasonable component design and ratio, the optical glass meets expected refractive index and abbe number and has low heat expansion coefficient.

The invention discloses a preparation method of a filled-type thermally conductive silicone rubber composite material. The processing steps of the method are as follows: 1) using alcohol solution to mix carbon-encapsulated copper nanoparticles evenly, and then drying the nanoparticles to prepare dry powder; 2) adding the raw silicone rubber onto a roller, after the raw rubber covers the roller, adding carbon-encapsulated copper nanoparticles dry powder and hydroxy silicone oil in sequence in accordance with the formulation design amounts; mixing the dry powder and the hydroxy silicone oil on the roller repeatedly until being uniform, then adding a vulcanizing agent, and then mixing the mixture uniformly, thin-passing a lower sheet to obtain the silicon rubber compound; 3) putting mixed silicone rubber into a mold, carrying out first vulcanization after cold pressing and mold filling; 4) putting a vulcanization-molded sample on a glass cloth and carrying out post vulcanization on the sample in an air dry oven to obtain finished products. The invention mixes the carbon-encapsulated copper nanoparticles and high-temperature silicone rubber to ensure that the carbon-encapsulated copper nanoparticles are evenly scattered in the silicone rubber substrate to form an integral thermally conductive network chain, thereby improving the thermal conductivity of the silicone rubber.

The invention discloses a multi-particle ceramic/metal compound heat dissipation substrate and a preparation method thereof. The heat dissipation substrate comprises a ceramic/metal compound material formed by compounding a plurality of ceramics with metal, an insulation layer and a circuit layer, wherein each ceramic and metal compound part is a particle in the ceramic/metal compound material; the total area of particles accounts for 10%-80% that of the ceramic/metal compound material. The heat dissipation substrate has the characteristics of high heat conduction rate, small heat expansion coefficient, low cost, convenience in use and the like, and is applied to the aspects of lamp decorations, communication electronic equipment, power modules, computers, automotive electronics and the like; the stress level of the connection layer of a chip or device substrate and the heat dissipation substrate can be greatly reduced, that the heat dissipation substrate is in close contact with heat sinks of lamps, machine cases and the like can be kept, a heat transfer passage is kept unblocked for a long term, the weight of the metal heat sinks can be reduced, and a heat transfer technology guarantee is provided for greatly prolonging the service lives of components and economically utilizing heat sink materials.

The invention discloses a corundum-zirconia corundum-titanic acid aluminum no-firing no-soaking sliding brick and a preparation method thereof. The sliding brick is composed of, by weight, 40-55 parts of tabular corundum, 15-25 parts of zirconia corundum, 10-15 parts of titanic acid aluminum, 6-10 parts of spherical calcined alumina, 5-8 parts of metal aluminum powder, 1-2 parts of high-temperature asphalt powder, 1-2 parts of silicon ash, 1-2 parts of antioxidants and 3-5 parts of phenolic resin. According to the corundum-zirconia corundum-titanic acid aluminum no-firing no-soaking sliding brick and the preparation method thereof, the raw materials of the tabular corundum, the zirconia corundum and the titanic acid aluminum are added into the formula, the coefficient of thermal expansion of the material of the sliding brick can be obviously decreased, and the thermal shock stability, the erosion resistance and the slag resistance of the sliding brick are improved; selection and adding amount of the high-temperature asphalt powder, spherical calcined alumina powder and the silicon ash are controlled, and the reasonable strength of the sliding brick in the low-temperature, medium-temperature and high-temperature stages can be achieved; the thermal expansion difference caused by the thermal stress of the temperature difference between inside and outside of the hole diameter of cast steel when the product is used is improved, the crack number is decreased; and the high-temperature comprehensive performance of the sliding brick is remarkably improved, and the service life of the sliding brick is prolonged.

The invention provides chrome-manganese nitrogen series austenitic heat-resistance steel, and belongs to the technical field of automotive steel. The chrome-manganese nitrogen series austenitic heat-resistance steel comprises 0.20%-0.50% of carbon, 0.50%-2.00% of silicon, 2.00%-5.00% of manganese, 0-0.04% of phosphorus, 0-0.03% of sulfur, 20.00%-27.00% of chromium, 6.00%-8.00% of nickel, 0-0.50% of molybdenum, 0-0.60% of niobium, 0-0.60% of tungsten, 0-0.15% of vanadium, 0.30%-0.60% of nitrogen, 0-0.10% of zirconium, 0-0.10% of cobalt, 0-0.10% of yttrium, 0-0.20% of boron and the balance Fe. The heat-resistance steel disclosed by the invention has the high-temperature strength, high heat conduction coefficient and low thermal expansion coefficient; moreover, the dimension is stable, ductility is good, heat resistance and impact resistance are achieved, production cost is low, and the operating requirement of a high-performance engine can be met.

The invention belongs to the technical field of non-oxide ceramic connection and discloses a high-entropy alloy connection silicon carbide ceramic connecting part as well as a preparation method and application thereof. The high-entropy alloy connection silicon carbide ceramic connecting part is prepared by mixing high-entropy alloy AlCoCrFeNi powder with SiC powder, performing stirring and ultrasonic treatment by using absolute ethyl alcohol as a solvent so as to obtain a uniform brazing filler metal, uniformly smearing the brazing filler metal to a SiC surface after polishing, and performingthermal treatment through SPS (spark plasma sintering) sintering at 1000-1400 DEG C at connection pressure of 5-30MPa, wherein the structure of the connecting part is SiC/AlCoCrFeNi-SiC/SiC. When thehigh-entropy alloy is used as a connecting layer, not only is low-temperature connection of a silicon carbide ceramic achieved, but also the internal stress of the ceramic connector can be reduced, and the connecting part can be applied to harsh working environments at high temperatures and high pressure, and particularly can be widely applied to the nuclear industry.

The invention belongs to the field of electronic ceramic materials, and particularly provides a magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material and a preparation method thereof which are used for overcoming the problems of high sintering temperature, large thermal expansion coefficient, low bending strength, high dielectric constant, high dielectric loss and the like of an existing ceramic material. The magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material and the preparation method thereof have the advantagesthat the prepared low-thermal-expansion-coefficient microcrystalline glass has low thermal expansion coefficient (1.0-2.0*10<-6> per DEG C), high bending strength (150-200 MPa), low dielectric constant (5.0-5.5 @1 MHz), low dielectric loss (1.5-3.5*10<-3> @1 MHz) and reliable insulation, thereby satisfying the requirements of an LTCC electronic package substrate material; the magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material can achieve low-temperature sintering at 900-950 DEG C, the process is simple, the stability is high, the production cost is low, and the magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material is suitable for industrial mass production.

The invention provides a near-zero thermal expansion composite material and a preparation method thereof. The preparation method comprises the following steps of: (a), mixing flux powder and tungstate solid solution precursor powder to obtain a first mixture, wherein the tungstate solid solution precursor has a chemical formula shown as the general formula (I) as follows: Zr(W1-yMoy)2-xVxO8-x/2(OH)2(H2O)2(I), in the general formula (I), x is more than or equal to 0 and less than or equal to 0.4, and y is more than or equal to 0 and less than 1; and the flux comprises PbO, B2O3 and SiO2; (b), pressing and forming the first mixture to obtain a formed body; and (c), roasting the formed body to obtain the near-zero thermal expansion composite material. In the invention, the near-zero thermal expansion composite material is prepared by mixing and roasting the flux comprising PbO, B2O3 and SiO2 and the tungstate solid solution precursor. Experimental results show that the thermal expansion coefficient of the near-zero thermal expansion composite material prepared by the preparation method disclosed by the invention in a temperature range of minus 50 to plus 300 degrees centigrade is in a range of +/- 2*10<-6>K<-1>.

The invention discloses a composite middle layer for performing diffusion bonding on silicon carbide ceramics and a bonding process thereof. The composite middle layer for performing diffusion bondingon the silicon carbide ceramics is prepared from the following components in percentage by weight: 55 to 65 percent of high-purity titanium hydride powder, 20 to 25 percent of high-purity silicon powder (Si), 12 to 17 percent of high-purity graphite powder (C), and 1 to 3 percent of high-purity aluminum powder (Al). According to the composite middle layer disclosed by the invention, by utilizinga spark plasma sintering technology (SPS), a silicon carbide (SiC) joint, of which the thickness of a bonding layer is 20 micrometers to 100 micrometers, is prepared under a vacuum condition. A bonding layer material mainly consists of a titanium silicon carbide (Ti3SiC2), the silicon carbide (SiC) and titanium carbide (TiC). Through changing the proportions of the raw materials and process parameters of sintering, the highest shearing strength at a room temperature reaches 135.8MPa, and the hardness of the composite material of the bonding layer can reach 28.1GPa, exceeding the hardness of SiC base materials; and therefore, the composite middle layer disclosed by the invention has a higher practical value.

The invention relates to an aluminum-based composite material, particularly relating to a preparation method of an aluminum-based composite material with low-thermal expansion coefficient. In the invention, aluminum powder with the powder granularity of 200 meshes and amorphous silicon dioxide powder are mixed in a ball-milling pot. Stainless steel balls different in diameter are put into the pot according to a certain ball to powder ratio. The mixture is then subjected to ball milling for a period in a planetary ball mill rotating at a certain speed; the ball-milled powder is put into a steel mould, the internal side of which and a pressure lever are coated with anhydrous alcohol or a release agent. The powder is slightly compacted and the surface is scraped flat, and then the powder is compacted with a certain pressure; the compacted sample is heated to the sintering temperature in a certain temperature-rising speed in a vacuum furnace, preserved for a period and cooled in the furnace under a vacuum condition. The sintered sample is detected for microstructure and performance.

The invention belongs to the technical field of a functional material, and relates to a novel heat dissipation insulating composite material and a preparation method therefor. Specifically, the novel heat dissipation insulating composite material consists of graphite, aluminum and ceramic, and adopts a sandwich structure, wherein a ceramic sheet layer is positioned in the middle, and graphite/aluminum composite sheet layers are positioned on the two sides; and the graphite/aluminum composite sheet layers consist of a graphite sheet layer with pores and aluminum for filling the pores. Integral forming of the graphite, metal aluminum and ceramic is realized by a high-pressure forging method to form the brand new composite material; the composite material has high thermal conduction, high insulativity and enhanced mechanical strength; and raw materials are low in coat, and the preparation method is simple and easy to implement, so that the composite material has high market competitiveness.

The present invention relates to an optical resin composition with excellent heat resistance and excellent impact resistance of multilayer film and a method for preparing an optical lens using the composition, and specially to a method for preparing the plastic glass lens which has the functions of excellent portability, excellent moldability, excellent dyeing property, excellent Abbe number, excellent transparency, ultraviolet obstructing property, etc. and has excellent heat resistance and excellent impact resistance of multilayer film. The present invention provides the optical resin composition which is obtained through mixing 38-68wt% of trivalent thiol ester compound and 32-62wt% of vulcabond compound after mixing with ultraviolet absorbent, demolding agent and polymerization initiator. The thermal expansion coefficient of glass lens prepared by the composition is lower and therefore the multilayer film does not easily split because of heating. The state of thermal deformation is less and the glass lens has excellent impact resistance.

The invention discloses a Cr/CrN/CrAlSiN/CrAlTiSiN nano-multilayer gradient film and a preparation method thereof, and belongs to the technical field of nitriding films. The Cr/CrN/CrAlSiN/CrAlTiSiN nano-multilayer gradient film is composed of a Cr base layer, a CrN transition layer, a CrAlSiN transition layer and a CrAlTiSiN film layer which are sequentially deposited on a low-alloy steel or mould steel base body by adopting a multi-arc ion plating method; the total thickness of the nano-multilayer gradient film is 1.5 [mu]m-4.2[mu]m; total content ranges of Cr, Al, Ti and Si elements are correspondingly 30at%-34at%, 20at%-28at%, 10at%-14at% and 3at%-5at%; and film base adhesion force of the nano-multilayer gradient film is 35-45N, the friction coefficient is 0.01-0.02, and nano-hardnessis 35-40 Gpa. According to the preparation method, by changing the base body negative bias and deposition time of middle layers and converting targets, the nano-multilayer gradient film with high tenacity, low friction coefficient and good abrasion performance is obtained.

The invention provides a camera lens and a depth of field calibration method thereof. The camera lens comprises a lens module, a central processing unit and a thermal expansion compensation module, wherein the lens module comprises a first mirror and a second mirror being a baseline length b2 away from the first mirror; and the first mirror comprises a first lens unit molded on the same glass substrate with the first mirror, and a second lens unit being a baseline length b1 away from the first lens unit. The first mirror is made of glass, and has a relatively low thermal expansion coefficient, so that the baseline length between the first lens unit and the second lens unit is basically not influenced by temperature variations, and can be taken as a standard value of a depth of field. Based on the standard value, a variation value of the baseline length between the second mirror and the first mirror can be obtained by calculation, so that thermal expansion of the camera lens can be calibrated.

The invention discloses a layer-shaped high thermal conductive and insulating base plate and a preparation method thereof, and belongs to the technical field of electronics. The high thermal conductive and insulating base plate is composed of a high thermal conductive composite material base body and an insulating film layer deposited on the high thermal conductive composite material base body; the high thermal conductive and insulating base plate is prepared by depositing the insulating film layer on the surface by adopting a physical or chemical method on the basis of the high thermal conductive composite material base body. The insulating base plate has the high thermal conductivity, the low-grade fever expansion factor, the high intensity and a good size stability performance, and further has the high disruptive strength, the high dielectric constant and other characters. According to the high thermal conductive and insulating base plate, the requirement of insulating function is met when an electronic packaging base plate is on the basis of maintaining a good heat dissipation of a base material.