Source: http://www.google.com/patents/US5382274?dq=5,870,513
Timestamp: 2017-03-26 15:47:51
Document Index: 9454892

Matched Legal Cases: ['Application No. 49', 'Application No. 52', 'Application No. 60', 'Application No.63', 'Application No. 63', 'Application No. 55']

Patent US5382274 - Mold with film of 0-5 atom % hydrogen and molding method utilizing same - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA mold for use for press-molding an optical element, in which a molding surface of a mold base material is coated with a hard carbon film containing 0-5 atom% of hydrogen. It has a spin density of 1×1018 spin/cm3 or less and a film density of at least 1.5 g/cm3....http://www.google.com/patents/US5382274?utm_source=gb-gplus-sharePatent US5382274 - Mold with film of 0-5 atom % hydrogen and molding method utilizing sameAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS5382274 APublication typeGrantApplication numberUS 07/999,124Publication dateJan 17, 1995Filing dateDec 31, 1992Priority dateAug 16, 1988Fee statusLapsedAlso published asUS5202156Publication number07999124, 999124, US 5382274 A, US 5382274A, US-A-5382274, US5382274 A, US5382274AInventorsKiyoshi Yamamoto, Keiji Hirabayashi, Noriko Kurihara, Yasushi Taniguchi, Keiko IkomaOriginal AssigneeCanon Kabushiki KaishaExport CitationBiBTeX, EndNote, RefManPatent Citations (17), Non-Patent Citations (4), Referenced by (17), Classifications (39), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetMold with film of 0-5 atom % hydrogen and molding method utilizing same
US 5382274 AAbstract
A mold for use for press-molding an optical element, in which a molding surface of a mold base material is coated with a hard carbon film containing 0-5 atom% of hydrogen. It has a spin density of 1×1018 spin/cm3 or less and a film density of at least 1.5 g/cm3.
1. A mold for use for press-molding an optical element, comprising at least the molding surface of a mold base material coated with a hard carbon film containing 0-5 atom% of hydrogen therein and having a spin density of 1×1018 spin/cm3 or less and a film density of 1.5 g/cm3 or more.
2. An optical element molding method comprising the steps of:preparing a hydrogenated amorphous carbon film (a-C:H) containing 5-40 atom% hydrogen; heat-treating said a-C:H film to obtain a hard carbon film containing 0-5 atom% hydrogen and having a spin density of 1×1018 spin/cm3 or less and a film density of 1.5 g/cm3 or more; coating a surface of a mold with said hard carbon film; setting an optical glass element in said mold; press-molding said optical glass element to form a desired optical article. Description
This application is a division of application Ser. No. 07/683,537 filed Apr. 10, 1991, now U.S. Pat. No. 5,202,156, which is a division of application Ser. No. 07/394,208 filed Aug. 15, 1989, now U.S. Pat. No. 5,026,415 issued Jun. 25, 1991.
The technique of manufacturing a lens by press-molding of a glass material without requiring a polishing process has eliminated the complicated stems heretofore required in the manufacture of a lens and has made it possible to make a lens simply and inexpensively, and has recently been used in the manufacture of not only a lens but also other optical elements formed of glass such as prisms.
As the characteristics required of a mold used for the press-molding of such an optical element of glass, mention may be made of the excellence in hardness, heat resisting property, parting property, mirror surface workability, etc. Heretofore, numerous materials such as metals, ceramics and materials coated therewith have been proposed as mold of this type. Mentioning some examples, Japanese Laid-Open Patent Application No. 49-51112 proposes 13Cr martensite steel, Japanese Laid-Open Patent Application No. 52-45613 proposes SiC and Si3 N4, and Japanese Laid-Open Patent Application No. 60-246230 proposed a super-hard alloy coated with a precious metal.
However 13 Cr martensite steel suffers from the disadvantages that it is ready to be oxidized and that Fe is diffused in glass at a high temperature to thereby color the glass, SiC and Si3 N4 are generally regarded as being difficult to be oxidized, but still suffers from the disadvantage that it is also oxidized at a high temperature and a film of SiO2 is formed on the surface thereof and therefore fusion with glass is caused and further the workability of the mold itself is very bad due to the high hardness. The material coated with a precious metal is difficult to be fused, but it is very soft, and this leads to the disadvantage that it is ready to be injured and also ready to be deformed.
Also, the diamond-like carbon film disclosed in Japanese Laid-Open Patent Application No.63-203222 is made into a film by the use of the plasma chemical vapor deposition (=PCVD) method under a condition of relatively high substrate temperature, and is the diamond-like carbon film of item (iii) containing a diamond crystal phase. Therefore, the film is of inhomogeneous quality and it is difficult to obtain a smooth film which is high in the surface accuracy. Further, in the repetitive molding process, the mold surface is oxidized little by little, but the film of inhomogeneous quality is not generally uniformly oxidized and therefore has the disadvantage that the deterioration of the surface roughness is keen. In addition, the crystallization of the film is ready to progress due to molding at high temperature, and this leads to the disadvantage that the quality of the film is deteriorated and the hardness and adhesion are deteriorated.
This film, when made, has no hydrogen atom contained therein and therefore is high in the homogeneity of film, but has the tendency that the better the surface smoothness, the greater the film stress becomes. This leads to the disadvantage that in the molding process, due to the release of the stress, the film is ready to peel off in a minute area or generally with the polishing flaw of the mold base material, the remaining polishing agent, dust, or the grain boundary or the partiality of composition of the mold base material as an occasion.
To achieve such an object there is provided a mold for press-molding an optical element, comprising at least the molding surface of a mold base material coated with a carbon film, the hard carbon film containing 0-5 atom% of hydrogen. The spin density is no more than 1×1018 spin/cm3 and the film density is at least 1.5 g/cm3.
The method of producing such mold comprises the steps of: preparing a hydrogenated amorphous carbon film (a-C:H) containing 5-40 atom % hydrogen, heat-treating the a-C:H film so as to obtain a hard carbon film containing 0-5 atom% hydrogen and having a spin density of 1.×1018 spin/cm3 and a film density of 1.5 g/cm3 or more, coating a surface of a mold with the hard carbon film, setting an optical glass element in said mold; and press-molding said optical glass element to form a desired optical article.
Particularly, to achieve the above first object, there are provided: (i) a mold used for press-molding an optical element, characterized in that at least the molding surface of the mold is coated with an a-C:H film containing 5-40 atom% of hydrogen and having a film density of 1.5 g/cm3 or more; (ii) mold used for press-molding an optical element, characterized in that at least the molding surface of the mold is coated with a hard carbon film containing 0-5 atom% of hydrogen and having a spin density of 1×1018 spin/cm3 or less and a film density of 1.5 g/cm3 or more; (iii) a method of manufacturing the mold of said item (i), characterized in that at least the molding surface of the mold is coated with a-C:H film by the plasma sputter deposition method or the plasma ion plating method made of a solid carbon source and in an atmosphere containing at least hydrogen; (iv) a method of manufacturing the optical element molding mold of said item (i), characterized in that at least the molding surface of the mold base material is coated with a-C:H film by the electron cyclotron resonance PCVD method or the ion beam deposition method; (v) a method of manufacturing the mold of said item (ii), characterized in that the heat treatment/annealing is carried out after a-C:H film is made; (vi) a method of manufacturing the mold of said item (v), characterized in that a-C:H film having a hydrogen content of 5-40 atom% and having a film density of 1.5 g/cm3 or more is heat-treated; and (vii) an optical element molding method characterized by molding an optical element by the use of mold of said item (i) or (ii).
The present invention forms, on at least the molding surface of the mold base material, a-C:H film which is relatively great in hydrogen content and low in hardness, and gradually decreases the hydrogen content to thereby obtain an inactive a-C:H film which is high in hardness, smooth and small in coefficient of friction on the surface side (the side of the surface of contact with glass) and which does not react the lead or alkali element in a high temperature state. Here, the film portion of the interface of the mold and the film which is great in hydrogen content has the action of absorbing the internal stress of the film and the difference between the coefficients of thermal expansion of the mold and the film, thereby improving the mechanical strength typified by the sticking property of the a-C:H film formed on the mold.
As regards the a-C:H film, it is preferable that the hydrogen content in the interface of the film with the mold base material be 60 atom% or less. If the hydrogen content exceeds 60 atom%, there is the tendency that it becomes difficult to construct C--C network of the film. (If the hydrogen content exceeds 66 atom% (C:H=1:2), it is impossible to construct the film.) Also, it is preferable that the hydrogen content in the surface be 5 atom% or more. If the hydrogen content is less than 5 atom%, double bond increases within the film and therefore the film becomes a graphite-like film, and this leads to the tendency that the hardness of the film becomes low and the problem that the lead oxide in the glass component is reduced arises.
Also, where the a-C:H film is constructed of two layers of films differing in hydrogen content, the film thickness of the layer greater in hydrogen content (40-60 atom% ) serves to absorb the internal stress of the film and the difference between the coefficients of thermal expansion of the mold and the film to thereby improve the adhesion of the film, but if the film thickness is too great, the characteristics (for example, the hardness) of the film greater in hydrogen content will become strong and therefore, it is preferable that the film thickness be 500-1000 Å. It is preferable that the film thickness of the layer smaller in hydrogen content (5-40 atom%) be 4000 Å or more to keep the film high in hardness and smooth, and if the film thickness of said layer exceeds 8000 Å, the influence of the internal stress of the film and the difference between the coefficients of thermal expansion of the mold and the film will become great and therefore, it is preferable that said film thickness be 4000-8000 Å.
Furthermore, the present invention proposes a mold in which the a-C:H film contains at lease one kind of halogen element selected from among F, Cl, Br and I, instead of at least one kind of element selected from nitrogen and oxygen.
In accordance with the present invention, there are provided: (1) a mold used for press-molding an optical element formed of glass, characterized in that at least the molding surface of the mold base material is coated with a-C:H film containing 5-40 atom% of hydrogen and carbon as the remainder and further, at least one kind of element selected from nitrogen ant oxygen; (2) said mold in which the a-C:H film contains at least one kind of inert gas element selected from among He, Ns, Ar, Kr and Xe, instead of at least one kind of element selected from nitrogen and oxygen: (3) said mold in which the a-C:H film contains at least one kind of halogen element selected from among F, Cl, Br and I, instead of at least one kind of element selected from nitrogen and oxygen; and (4) said mold in which the a-C:H film contains at least one kind of element selected from among He, Ns, Ar, Kr and Xe, in addition to at least one kind of element selected from nitrogen and oxygen.
The composition of this a-C:H is 5-40 atom% of hydrogen and carbon as the remainder.
Here, it is for the following reason that the hydrogen content has been limited. The relations as shown in FIGS. 1 and 2 of the accompanying drawings are obtained between the hydrogen content in a-C:H and the hardness of the film and the roughness of the surface. As seen from FIG. 1, as hydrogen content increases, the hardness is reduced, and if the hydrogen content exceeds 40 atom%, Knoop hardness becomes less than 800 kg/mm2 and desired film hardness becomes unobtainable. Also, as seen from FIG. 2, as the hydrogen content decreases, the roughness of the surface increases, and for less than 5 atom%, the roughness of the surface exceeds 0.05 μat Rmax and a desired mirror surface property becomes unobtainable. The increase or decrease in the amount of hydrogen for obtaining the relations of FIGS. 1 and 2 has been effected by the use of the deposition apparatus of FIG. 5 of the accompanying drawings and with the acceleration voltage 500 V and the substrate temperature 300° C., among the conditions of making film, being constant and with the gas flow rate of CH4 and H2 changed.
The a-C:H film of item (3) containing at least one kind of halogen element selected from among F, C, Br and I reduces the wettability with respect to glass by its containing the halogen and therefore, the parting property during molding is improved, and during repetitive molding, the changes in the composition and structure of the a-C:H film are suppressed, and this leads to the improved durability of the mold.
The amount of nitrogen and oxygen contained in the a-C:H film of item (4) containing at least one kind of inert gas element selected from among He Ne, Ar, Kr and Xe, in addition to at lease one kind of element selected from nitrogen and oxygen, may preferably be within the range of 100-50,000 atom ppm, and the amount of inert gas element contained in said film may preferably be within the range of 100-5,000 atom ppm.
The a-C:H films of items (1)-(4) may contain not only amorphous structure, but also a small amount or crystallite. However, this crystallite can be a minute diamond grain of the order of 0.01-0.1 μm, but a crystallite whose diamond crystal surface appears clearly on the surface of the film is not preferable. Also, it is preferable that the crystallite do not contain graphite and multiple bond as far as possible, but the graphite and multiple bond may contain them if in a small amount.
It is preferable that the film thickness of the a-C:H film be 0.05-0.5 μm. If the film thickness is less than 0.05 μm, the component element of the mold base material will dissolve into glass during molding and the durability of the molding mold wall tend to be reduced, and if the film thickness exceeds 0.5 μm, the distortion in the film will become great and the peeling-off of the film will become readily to occur.
As the mold base material, a material containing a component element capable of producing a carbide is preferable, and mention may be made, for example, of super-hard alloy (containing WC as a chief component), SiC, AlN, cermet or the like.
Description will first be made of a-C:H film containing 5-40 atom% of hydrogen and having a film density of 1.5 g/cm3 or more.
Here, it is for the following reason that the amount of hydrogen has been limited. The relations shown in FIGS. 1 and 2 are obtained among the amount of hydrogen content in a-C:H and the hardness of the film and the roughness of the surface. It is seen from FIG. 1 that if the hydrogen content increases, the hardness is reduced and if the amount of hydrogen exceeds 40 atom%, Knoop hardness becomes less than 800 kg/mm2 and desired film hardness becomes unobtainable. Also, it is seen from FIG. 2 that if the hydrogen content decreases, the roughness the surface increases and for less than 5 atom%, the roughness of the surface exceeds 0.05 μm at Rmax and a desired mirror surface property becomes unobtainable. The increase and decrease in the hydrogen content or obtaining the relations of FIGS. 1 and 2 have been effected by the use of the film making apparatus of FIG. 5 with the acceleration voltage 500 V and the substrate temperature 300° C. among the conditions of making a film being constant and with the ratio of CH.sub. 4 /H2 gas flow rate being changed.
Also, to hold the sufficient adhesion/adherence and mechanical strength of the mold base material and the film under the temperature condition during molding, it is preferable that the coefficient of thermal expansion α of the film be within the range of 1×10-6 ≦α≦1×10-5 [K-1 ].
Description will now be made of a method of manufacturing a mold which is coated with a-C:H film.
Description will now be made of a hard carbon film containing 0-5 atom% of hydrogen and having a spin density of 1×1018 spin/cm3 or less and a film density of 1.5 g/cm3 or higher.
Where molding is effected at a high temperature, or where in the molding process, glass containing an element such as lead which is ready to be reduced and deposited is used in the interface between the molded glass and the mold, or where molding is effected under a condition in which reduction and deposition are ready to occur, a hard carbon film containing 5 atom% or less of hydrogen in the film or containing no hydrogen in the film and having a spin density of 1×1018 spin/cm3 or less is preferable. If the hydrogen content exceeds 5 atom%, the surface of the molded glass will become cloudy due to a reduced metal particularly during the several first moldings, and this is not preferable from the viewpoints of the optical characteristic and the appearances. If the spin density exceeds 1×1018 spin/cm3, peeling-off of the film will occur due to the heat shock resulting from molding, and this is not preferable.
The film thickness of said hard carbon film may preferably be 100-20000 Å, and if the film thickness is less than 100 Å, the reactivity to glass will occur, and if the film thickness exceeds 20000 Å, peeling-off of the film will occur, and this is not preferable.
The film hardness of said hard carbon film may be higher than the hardness of the molded glass, and may preferably be 800 kg/mm2 or more. If the film hardness is less than 800 kg/mm2, the surface accuracy of the molded glass will tend to become insufficient, and this is not preferable.
Said hard carbon film can be produced by heat-treating the aforementioned a-C:H film containing 5-40 atom% of hydrogen and having a film density of 1.5 g/cm3 or more.
The reason why it is preferable to use a-C:H film containing 5-40 atom% of hydrogen in the heat treatment will hereinafter be described.
Generally in a hard carbon film, the film hardness is high and the degree of cross-rink of the carbon-carbon network is high, and in a smooth amorphous film, the stress is high, and a film in which the stress is too high becomes the cause of the film peeling off in the whole surface or a minute area with the polishing flaw of the base material, the grain boundary, the dust or the like having adhesion to the film before film making as an occasion. If the peeling-off of the film is such that the film peels off in a minute area of the order of several tens to several hundred μm, if not in the whole surface, due to a reduced adhesion, the roughness of the surface of the molded glass will increase though locally, and this will become the cause of the molded glass becoming cloudy and thus will pose a problem in terms of the optical characteristic and appearances. So, even if the degree of cross-ink of the carbon-carbon network is controlled with a view to control the stress, if unbonded hands which could not be bonded to carbon are present in the form of dangling bond in the film, the effect of alleviating the stress will be small and also, this will provide an active site for reacting to oxygen, and this is not preferable.
That is, a film in which hydrogen has been made into a film to 0-5 atom% immediately after the making of the film generally has much dangling bond, and when the film is removed from a chamber for preservation after the making of the film or is heated, the film is liable to peel off or be oxidinized and deteriorated, and this is not preferable.
Also, if a film in which hydrogen is 0-5 atom% and the stress has been alleviated is formed in the film making process, the film will become inhomogeneous in quality and crystallized and will exhibit a tendency toward the reduced roughness of the surface and the reduced structural strength of the film, and this is not preferable.
So, even if the hydrogen content is increased to terminate the dangling bond, if the hydrogen content exceeds 40 atom%, the degree of cross-ink of the carbon-carbon network will be reduced too much and particularly at the molding temperature, the hardness of the film and the roughness of the surface of the film will be reduced or glass will be fused, and this is not preferable.
The heat treatment conditions differ depending on the kind of the glass to be molded, the molding temperature and the qualities of film such as film density and the hydrogen content, and the lower limit of the heat treatment temperature may preferably be 400° C. or the upper limit of the molding temperature may preferably be 750° C. If the heat treatment temperature is less than 400° C., the effect of dehydrogenation and the effect of obtaining good molded glass from the first molding will be difficult to obtain. If the heat treatment temperature exceeds 750° C., deterioration such as the oxidation of the a-C:H film and graphite crystallization will progress and the structural strength of the hard carbon film will be deteriorated, and this is not preferable. More preferably, the heat treatment temperature is above 500° C. and below 650° C.
The heat treatment atmosphere may preferably be inactive or inert gas such as He, Ne, Ar, Kr, Xe or the like or of N2 or H2 gas or a mixture of two or more kinds of gases of these gases or in a reduced pressure thereof, and the partial pressure of oxygen in the atmosphere may preferably be 1×10-1 Torr or less. If the partial pressure exceeds 1×10-1 Torr, the a-C:H film will be oxidinized and the thickness of the hard carbon film will decrease too much or the hardness of the film and the structural strength of the film will be reduced, and this is not preferable.
FIG. 3 shows the state before the press-molding of an optical element, and FIG. 4 shows the state after the press-molding of the optical element. In FIG. 3, the reference numerals 1 and 2 designate mold base materials the reference characters 1-a and 2-a denote a-C:H films or hard carbon films formed on the molding surfaces of the mold base materials which contact with a glass blank, and the reference numeral 3 designates the glass blank, and in FIG. 4, the reference numeral 4 denotes the optical element.
In FIG. 5, the reference numeral 11 designates a vacuum chamber, the reference numeral 12 denotes an ion beam apparatus, the reference numeral 13 designates an ionization chamber, the reference numeral 14 denotes a gas inlet port, the reference numeral 15 designates an ion extractive grid, the reference numeral 16 denotes an ion beam, the reference numeral 17 designates a mold substrate, the reference numeral 18 denotes a substrate holder and a heater, and the reference numeral 19 designates an exhaust outlet. When the a-C:H film is to be formed, the mold base material 17 having its surface cleaned by an organic solvent is installed on the holder 18 and the air is exhausted through the exhaust outlet 19 to thereby make the interior of the chamber 11 vacuum, The mold base material 17 is heated to 300C and a source gas of CH2 +H2 is introduced into the chamber through the gas inlet port 14 (CH4 /H2 =0.1). The source gas is ionized in the ionization chamber 13 of the ion beam apparatus 12, and a voltage of 300 V is applied to the ion extractive grid 15 to thereby draw out an ion beam, which is applied to the base material 17 to a predetermined film thickness. In the manner described above, a mold coated with a-C:H film was manufactured.
TABLE 1______________________________________No.      Coating material                 Base material______________________________________1        None         WC(90%) + Co(10%)2        None         SiC3        SiC          WC(90%) + Co(10%)4        a-C:H        WC(90%) + Co(10%)5        a-C:H        SiC______________________________________
The base material of the mold is first worked into a predetermined shape, and the lens molding surface thereof is polished into a mirror surface. A coating of SiC is then formed by the ion plating method. Also, a coating of a-C:H film containing 40 atom% of hydrogen is constructed by the ion beam chamber method. The film thickness was 0.1 μm. Optical glass of the flint line (SF14) is then regulated to a predetermined amount, and a glass blank made into a spherical shape is placed in the cavity of the mold and is installed in the apparatus.
The valve 62 is opened to start exhaust, and when 10-2 Torr or less is reached, the valve 62 is closed, and the valve 66 is opened to introduce nitrogen gas from a bomb into the vacuum chamber. When a predetermined temperature is reached, the air cylinder 60 is operated to press at a pressure of 10 kg/cm2 for five minutes. After the pressure is removed, cooling is effected until the cooling speed becomes less than the transition point at -5° C./min, whereafter cooling is effected at a speed above -20° C./min, and when the temperature falls to 200° C. or less, the valve 66 is closed and the vent valve 63 is opened to introduce air into the vacuum chamber 51. The lid 52 is then opened, the upper mold keeper is removed and the molded article is taken out.
In the manner described above, the lens 4 shown in FIG. 4 was molded by the use of optical glass SF14 of the flint line (softening point Sp=586° C. and transition point Tg=485° C.). The then molding condition, i.e., the time-temperature relation, is shown in FIG. 11.
TABLE 2__________________________________________________________________________              Roughness of surface Rmax (&#956;m)No.   Coating   Base material              Lens                 Mold (before molding)                             Mold (after molding)                                        Parting property__________________________________________________________________________1  None WC(90%) + Co(10%)              0.04                 0.02        0.03       Good2  None SiC        -- 0.04        --         Fused3  SiC  WC(90%) + Co(10%)              -- 0.02        --         Fused4  a-C:H   WC(90%) + Co(10%)              0.03                 0.02        0.02       Good5  a-C:H   SiC        0.05                 0.04        0.04       Good__________________________________________________________________________
Film making was done by the use of the same deposition apparatus as that in Embodiment 1 and with the deposition conditions changed. With the ratio of the mixed gases being CH4 /H2 =1 and the substrate temperature being 500° C. and the extractive voltage being 250 V, there was obtained a-C:H film containing 15 atom% of hydrogen and having a film thickness of 0.5 μm.
The interior of the molding chamber 106 is divided into a heating zone 106-1, a press zone 106-2 and a gradually cooling zone 106-3 along the direction of conveyance of the pallet. In the press zone 106-2, an upper mold member 130 for molding is fixed to the lower end of the rod 134 of the cylinder 138 and a lover mold member 132 for molding is fixed to the upper end of the rod 136 of the cylinder 140. These upper and lower mold members 130 and 132 are the mold members of FIG. 3 according to the present invention. A container 142 containing an evaporation materials 146 therein and heaters 144 for heating this container are disposed in the evaporation chamber 108.
Optical glass of the flint line (SF14, the softening point Sp=586° C., the glass transition point Tg=485° C.) was roughly worked into a predetermined shape and dimensions, whereby a blank for molding was obtained.
The glass blank was mounted on the pallet 120, and was placed at a position 120-1 in the replacement chamber 104 for taking-in, and the pallet at this position was pushed in the direction of arrow A by the rod 122 of the cylinder 124 and was conveyed to a position 120-2 in the molding chamber 106 beyond the gate valve 112, whereafter in the same manner, pallets were newly successively placed into the replacement chamber 104 for taking-in at predetermined timing, and each time, the pallets were successively conveyed to positions 120-2 →. . . → 120-8 in the molding chamber 106. In the meantime, in the heating zone 106-1, the glass blank was gradually heated by he heaters 128 and was rendered to the softening point or above at the position 120-4, whereafter it was conveyed to the press zone 106-2, whereupon the cylinders 138 and 140 were operated and the glass blank was pressed by the upper mold member 130 and the lower mold member 132 with a pressure of 10 kg/cm2 for five minutes, whereafter the pressing force was released and the glass blank was cooled to the glass transition point or below, whereafter the cylinders 138 and 140 were operated to thereby part the upper mold member 130 and the lower mold member 132 from the molded glass article. During said pressing, the pallet was utilized as a side mold member for molding. Thereafter, the molded glass article was gradually cooled in the gradually cooling zone 106-3. The molding chamber 106 was filled with inert gas.
The roughness of the molding surfaces of the mold members 130 and 132 before and after the press-molding as described above, the roughness of the optical surface of the molded optical element and the parting property of the molded optical element with respect to the mold members 130 and 132 are shown Table 4 below.
TABLE 4__________________________________________________________________________              Roughness of surface Rmax (&#956;m)No.   Coating   Base material              Lens                 Mold (before molding)                             Mold (after molding)                                        Parting Property__________________________________________________________________________1  None WC(90%) + Co(10%)              0.04                 0.02        0.03       Good2  None SiC        -- 0.04        --         Fused3  SiC  WC(90%) + Co(10%)              -- 0.02        --         Fused4  a-C:H   WC(90%) + Co(10%)              0.03                 0.03        0.03       Good5  a-C:H   SiC        0.05                 0.04        0.04       Good__________________________________________________________________________
TABLE 5______________________________________Number          Roughness of surface Rmax &#956;mNo.    of molding   Lens      Mold______________________________________1       200         0.14      0.15  1000         0.20      0.21  5000         0.23      0.24  10000        0.26      0.274       200         0.03      0.03  1000         0.03      0.03  5000         0.03      0.03  10000        0.04      0.035       200         0.05      0.04  1000         0.05      0.04  5000         0.05      0.04  10000        0.05      0.05______________________________________
a-C:H films having a film thickness of 0.03-0.60 μm were heaped up on the surface of a mold base material comprising WC 90% and Co 10% by the ECR-PCVD method. The ECR-PCVD apparatus is of the cavity type shown in FIG. 6, and a magnetic field is applied to a cavity 21 by an electromagnet 22, and a microwave is introduced from a microwave introduction window 24 through a waveguide tube 23 and gas is introduced from a gas inlet port 27 into the cavity, and the gas is excited.
The magnitude of the magnetic field was set so as to be 2000 gauss at the microwave introduction window and 875 gauss on the surface of the mold. A mold 26 supported on a mold holder 25 was installed outside the cavity, as shown in FIG. 6. Ethylene (5 SCCM) and hydrogen (20 SCCM) were introduced from the gas inlet port 27 into the ECR-PCVD apparatus, and the pressure, the microwave power and the mold surface temperature were set to 2×10-3 Torr, 500 W and 300° C., respectively. When under such conditions, deposition was effected for three minutes, four minutes, seven minutes, ten minutes, twenty minutes and twenty-five minutes, respectively, a-C:H films having film thickness of 0.03, 0.05, 0.10, 0.22, 0.50 and 0.60 μm, respectively, were formed on the surface of the mold base material. When the hydrogen content in these films was measured by combustion analysis, it was 30 atom%. The Knoop hardness was 1500 kg/mm2.
TABLE 6______________________________________      Roughness of surface Rmax (&#956;m)Film thickness     Mold       MoldNo.  (&#956;m)     Lens   (before molding)                              (after molding)______________________________________6    0.03        0.08   0.02       0.087    0.05        0.03   0.02       0.028    0.10        0.03   0.02       0.029    0.22        0.03   0.02       0.0210   0.50        0.03   0.02       0.0211   0.60        0.03   0.02       0.02______________________________________
TABLE 7______________________________________Film thickness   Roughness of surface Rmax (&#956;m)No.    (&#956;m)       Lens     Mold______________________________________7      0.05          0.05     0.048      0.10          0.04     0.039      0.22          0.04     0.0310     0.50          0.04     0.0311     0.60          --       Film peeled.______________________________________
FIG. 7 shows a RF sputtering apparatus used in the present embodiment. The reference numeral 3i designates a vacuum chamber, the reference numeral 32 denotes a mold base material comprising super-hard alloy and a substrate holder, the reference numeral 33 designates the target of a solid carbon source (usually graphite), and the reference numeral 34 denotes a target holder which is cooled by cooling water passing through inlet and outlet ports 35. The reference numeral 36 designates a RF power supply for applying a RF (or rf) to the target holder and matching device. The reference numeral 37 denotes gas inlet port, and the reference numeral 38 designates an exhaust port connected to an exhaust apparatus, not shown. It is to be understood that the atmosphere in which the a-C:H film is formed is such that hydrogen gas is introduced and the pressure is adjusted to 1×10-3 Torr to the order of 1 Torr. The hydrogen gas introduced at this time may be hydrogen 100%, but may also be mixed with inert gas such as argon, neon or helium for the stabilization of discharge. The mold base material is heated by a heater, not shown, in the substrate holder. The optimum substrate temperature differs depending on the conditions under which the mold is used for press-molding and the quality of the glass, but generally is 200°-400° C. By a RF (usually a frequency of 13.56 MHz) being applied to the target and the target holder, the carbon source of the target is sputtered and carbon films are deposited on the mold base material. In this manner, the mold base material is coated with a-C:H film having a film thickness of the order of 0.2-1.5 μm.
By the use of the film deposition apparatus shown in FIG. 7, a-C:H film was formed on the mold base material comprising WC(90%) and Co(10%). 10 SCCM of Ar and 10 SCCM of H2 were first introduced, and a valve, not shown, was adjusted to render the pressure to 0.1 Torr. The mold base material was heated to 300° C. by a heater, whereafter a RF power source of 350 W was applied thereto and deposition was started. By approximately one hour of film deposition, a-C:H film having a film thickness of 0.5 μm was formed on the mold base material. The mold thus obtained is referred to as No. 12. When the hydrogen content in this film was measured by combustion analysis, it was 24 atom%.
By the use of the deposition apparatus of FIG. 7 and with the conditions of deposition changed in the following manner, a-C:H film was deposited on the mold base material comprising WC(90%) and Co(10%). 20 SCCM of Ar and 5 SCCM of H2 were first introduced, and a valve, not shown, was adjusted to render the pressure to 1×10-2 Torr. The mold base material was heated to 350° C. and a RF power of 300 W was applied thereto. By approximately one hour of deposition, a-C:H film of 0.4 μm was formed. The mold thus obtained is referred to as No. 13. When the hydrogen content in this film was measured by combustion analysis, it was 12 atom%.
By the use of each mid coated with the a-C:H film, molding was effected 200 times in the same manner as in Embodiment 1, whereafter the roughness of the surface was measured. The result is shown in Table 8 below.
TABLE 8______________________________________    Roughness of surface Rmax (&#956;m)No.        Lens       Mold______________________________________12         0.03       0.0213         0.03       0.02______________________________________
TABLE 9______________________________________               Roughness ofNumber              surface Rmax (&#956;m)No.     of molding      Lens   Mold______________________________________12       200            0.03   0.03   1000            0.03   0.03   5000            0.03   0.03   10000           0.04   0.0313       200            0.03   0.03   1000            0.03   0.03   5000            0.03   0.03   10000           0.04   0.03______________________________________
A method of manufacturing a mold by the plasma ion plating method will hereinafter be described with reference to FIG. 5.
FIG. 8 shows an on plating apparatus used in the present embodiment. The reference numeral 41 designates a vacuum chamber, the reference numeral 42 denotes a mold base material comprising super-hard alloy and a substrate holder, the reference numeral 43 designates a DC power supply, the reference numeral 44 denotes a RF coil, the reference numeral 45 designates a RF power supply and a matching box, the reference numeral 46 denotes an electron gun, the reference numeral 47 designates a solid carbon source, the reference numeral 48 denotes a gas inlet port, and the reference numeral 49 designates an exhaust port connected to an exhaust system, not shown.
It is to be understood that the atmosphere in which a-C:H film is formed in such that a mixture of hydrogen gas and inert gas is introduced and the pressure is regulated to the order of 1×10-5 -1×10-3 Torr. With hydrogen gas alone, discharge becomes unstable and therefore, mixing inert gas (such as helium, neon or argon) therewith is desirable. The mold base material is heated by the use of a heater, not shown. The substrate temperature may generally be of the order of 200°-400° C. The carbon source is provided by evaporating solid graphite or the like by the use of an electron gun. At this time, the introduced gases are made into plasma by the use of the RE coil (usually a frequency of 13.56 MHz) and further, a bias 50-1000 V of negative voltage is applied to the mold base material and ions are applied to the mold base material, thereby forming a-C:H film having a film thickness of the order of 0.2-1.5 μm on the mold base material, whereby the mold of the present invention is manufactured.
By the use of the deposition apparatus shown in FIG. 8, a-C:H film was formed on the mold base material comprising WC(90%) and Co(10%). 10 SCCM of Ar gas and 10 SCCM of H2 gas were introduced to render the pressure to 2×10-4 Torr. The mold base material was heated to 250° C., and a bias or -250 V was applied thereto. Further, a RF of 300 W was applied to the RF coil and graphite was evaporated by the electron gun, whereby a-C:H film of 0.5 μm was formed on the mold base material. The mold thus obtained is referred to as No. 14.
With the conditions of deposition changed the following manner, a-C:H film was formed on the mold base material comprising WC(90%) and Co(10%). 7 SCCM of Ar gas and 20 SCCM of H2 gas were introduced, the pressure was rendered to 1.5×10-4 Torr, and the mold base material was heated to 300° C., and a bias of -400 V was applied thereto. Further, a RF power of 250 W was applied to the RF coil, and graphite was evaporated by the electron gun, whereby a-C:H film or 0.5 μm was formed on the mold base material. The molding mold thus obtained is referred to as No. 15.
TABLE 10______________________________________        Roughness of        surface Rmax (&#956;m)No.            Lens   Mold______________________________________14             0.03   0.0215             0.03   0.02______________________________________
TABLE 11______________________________________               Roughness ofNumber              surface Rmax (&#956;m)No.     of molding      Lens   Mold______________________________________14       200            0.03   0.03   1000            0.03   0.03   5000            0.03   0.03   10000           0.04   0.0315       200            0.03   0.03   1000            0.03   0.03   5000            0.03   0.03   10000           0.04   0.03______________________________________
TABLE 12__________________________________________________________________________Sample    Pressure    Substrate      Spin density                           H content                                 Film density                                        Film hardness                                               Roughness of surfaceNo. (Torr)    temp. (°C.)          Substrate bias (V)                   (spin/cm3)                           (atom %)                                 (g/cm3)                                        (kg/mm2)                                               (Rmax__________________________________________________________________________                                               &#956;m)16  1 × 10-2    150      0     1 × 1017                             60  1.3     400   0.0217  1 × 10-2    300      0     2 × 1017                             40  1.5    1000   0.0318  1 × 10-4    150    -400    5 × 1018                             10  1.8    1600   0.0119  1 × 10-4    150    -500    5 × 1018                              5  1.8    1800   0.0120  1 × 10-4    150   -1000    1 × 1020                              2  2.0    1800   0.0121  1 × 10-4    450    -500    2 × 1018                              2  1.5     800   0.06__________________________________________________________________________ Nos. 16, 20 and 21 show comparative examples.
First, low melting point glass of a glass transition point 292° C. and a yield point 319° C. (glass of a softening point of about 342°-370°-C. disclosed in Japanese Laid-Open Patent Application No. 63-170241) was roughly worked into a predetermined shape and dimensions, whereby there was obtained a blank for molding.
However, the temperature of the glass blank at a position 120-4 was rendered to 320°-335° C., whereafter the temperatures of the upper mold member 130 and the lower mold member 132 were rendered to 335° C., and the glass blank was pressed with a pressure of 100 kg/cm2 for one minute, whereafter the pressure force was released and the glass blank was cooled to 230° C. and parted from the mold.
After such press-molding was carried out 50 times, the mold was removed from the molding apparatus to examine the hardness of the film and the peeking-off state of the film. Here, judgment as to the peeling-off state of the film is such that a case where peeling-off by 0.1 μm or more is not found when examined by a scanning electron microscope (SEM) is judged as there being no peeling-off and a case where peeling-off by 1 μm or more is found when examined by an optical microscope and a case where peeling-off by 0.1 μm or more is found when examined by the SEM are judged as there being peeling-off (this also holds true hereinafter). The result is shown in Table 13 below.
TABLE 13______________________________________  Number    Film hardnessNo.    of molding            (kg/mm2)                         Peeling-off of film______________________________________16     1st    time   --         Fusion of glass17     50th   time    700       None18     50th   time   1600       None19     50th   time   1800       None20     12th   time   --         Peeling-off (3 &#956;m)21     20th   time   less than 100                           Peeling-off (10 &#956;m)                           Fusion of glass______________________________________
By the use of the deposition apparatus of FIG. 7, the conditions of deposition were set as follows, and a hard carbon film was formed on a mold base material comprising WC(90%) and Co(10%) and having surface roughness Rmax 0.02 μm. First, 10 SCCM of Ar and 10 SCCM of H2 were introduced, and a valve, not shown, was adjusted to render the pressure to 5×10-2 Torr. The mold base material was heated to 150° C., and an RF power of 300 W was applied thereto. By approximately one hour of deposition, a-C:H film having a film thickness of 5000 Å was formed. The mold thus obtained is referred to as No. 22.
This film hard a hydrogen content of 12 atom%, a density of 1.8 g/cm3, surface roughness Rmax 0.02 μm and a spin density of 5×1018 spin/cm3.
On the other hand, a mold on which a film was deposited under the same conditions as No. 22 with the exception that the introduced gas was changed to 20 SCCM of Ar gas is referred to as No. 23. The film of this mold contained very little hydrogen and had a density of 2.1 g/cm3, surface roughness Rmax 0.01 μm and a spin density of 5×1019 spin/cm3.
By the use of glass of a glass transition point 365° C. and a yield point 397° C. (glass of an American softening point of about 390°-435° C. disclosed in Japanese Laid-Open Patent Application No. 55-154343), molding was effected at a molding temperature of 415° C. and a molding pressure of 100 kg/cm2 and for a pressing time of one minute.
The mold of No. 23, after the 21st molding, exhibited much peeling-off of a minute area of several tens to several hundred μm in diameter at the marginal portion of the surface of the mold, and became cloudy at locations corresponding to the portions of the molded glass surface in which the film peeled off, and had surface roughness of Rmax 0.1 μm.
When a hard carbon film is to be formed, a mold base material 17 having its surface cleaned by an organic solvent and comprising WC(95%) and Co(5%) (surface roughness of Rmax 0.02 μm) is installed on a holder 18, and the air is exhausted from an exhaust port 19 to render the internal pressure of a chamber 11 to 5×10-7 Torr.
Subsequently, from a gas inlet port 14, a mixture of gases CH4 and Ar is introduced at a mixture ratio CH4 /Ar=1/1 to render the interior of a chamber 11 to 1×10-4 Torr. The raw material gases are ionized by the ionization chamber 13 of an ion gun 12, and a voltage of 500 V is applied to an ion beam extractive grid 15 and an ion beam is applied to a draw-out base material 17 to thereby deposite. At this time, the ion beam current was 0.6 mA/cm2, and the heating of the substrate was not specially done.
The heating process was carried out for two hours in an atmosphere in which the partial pressure of oxygen which is an impurity in N2 has of 1.2 atmospheric pressure was 5×10-3 Torr or less.
By the use of glass of the SF8 flint line (made of OHARA, having a transition point 444° C. and a yield point 476° C. and containing lead element), press-molding was effected at a molding temperature of 520° C. and a molding pressure or 100 kg/cm2 for one minute.
TABLE 14__________________________________________________________________________                                                   Pb peak                                        After molding                                                   intensity ofMold member After heating process (before molding) Hardness                                                   moldedSample    heat treatment       Hardness             Surface roughness                      Density                           Spin density                                  H content                                        Peeling-off                                              (kg/ glassNo. temp. (°C.)       (kg/mm2)             Rmax (&#956;m)                      (g/cm3)                           (spin/cm3)                                  atom %                                        of film                                              mm2)                                                   surface__________________________________________________________________________                                                   (cps)24  No process       1600  0.01     1.8  5 × 1018                                  13    &#8728;                                              1400 35025  350     1500  0.01     1.8  1 × 1019                                  6     &#8728;                                              1500 33026  400     1600  0.01     1.8  2 × 1017                                  4     &#8728;                                              1500 18027  500     1400  0.02     1.9  2 × 1017                                  1     &#8728;                                              1400 4028  550     1500  0.01     1.9  less than                                  1     &#8728;                                              1400 0                           101729  600     1500  0.02     1.9  less than                                  0     &#8728;                                              1500 0                           101730  650     1300  0.02     1.9  less than                                  0     &#8728;                                              1200 0                           101731  750      800  0.05     1.8  less than                                  0     &#916;                                               800  0                           101732  850     less than             0.08     1.7  less than                                  0     x     --   --        500                1017__________________________________________________________________________ &#8728;: no peelingoff of film &#916;: peelingoff in minute areas x: generaly pealingoff No. 24 shows a comparative example.
By the use of a mold base material similar that in Embodiment 8, a hard carbon film was made to a film thickness of 12000 Å on the molding surface in a similar manner, whereby a mold member was made. The heat treatment was carried out at 520° C. for one hour in an atmosphere in which the partial pressure of oxygen was controlled and the total pressure was rendered to 1.2 atmospheric pressure by introducing a mixture of {O2 (1%)+Ar(99%)} gas and Ar gas. Glass was press-molded by an apparatus similar to and under conditions similar to Embodiment 8. The partial pressure of oxygen during the heating process and the result of molding are collectively shown in Table 15 below.
The hardness before the heat treatment was 1400-1600 kg/mm2. The mark x in the column of the molding property shows that the deterioration of the film hardness and he structural strength during the heating process was keen and fusion of glass and the film and peeling-off of the film occurred and molding could not be accomplished, the mark Δ shows that molding could be accomplished, but the surface accuracy of the molded glass surface was insufficient due to the peeling-off of the film of the mold, and the mark o shows that molding was good.
TABLE 15______________________________________Partial pressure Hardness ofof oxygen during mold afterheat treatment   heat treatment                             MoldingNo.  (Torr)           (kg/mm2)                             property______________________________________33   5 × 10-1                 less than 500                             x34   1 × 10-1                  800        &#916;35   1 × 10-2                 1200        &#8728;36   5 × 10-3                 1500        &#8728;37   less than 1 × 10-3                 1400        &#8728;______________________________________
Use was made of the mold base material 17 comprising WC(84%) - TIC(8%) - TaC(8%) and having surface roughness of Rmax 0.02 μm, and the surface thereof was cleaned by an organic solvent, whereafter the mold base material was installed on the holder 18, and the air is exhausted from the exhaust port 19 to render the interior of the chamber 11 to 5×10-7 Torr.
Subsequently, a mixture of assist gas H2 and Ar gas was introduced from the gas inlet port 14 to render the interior of the chamber 11 to 2×10-4 Torr. The assist gas was ionized in the ionization chamber 13 of the ion gun 12, and was drawn out into the ion beam extractive grid 15, and a voltage was applied thereto and an ion beam was extracted and applied to the mold base material 17.
The heat treatment was carried out in an Ar gas atmosphere of 1.2 atmospheric pressure the partial pressure of oxygen 1×10-2 Torr or less) at 600° C. for two hours.
Any of the films of Nos. 38-43 contained very little hydrogen after the heat treatment, and had a spin density of 1×1018 spin/cm3 or less.
Subsequently, a molding test was carried out with respect to Nos. 38-41 having sufficient hardness after the heat treatment. The molding apparatus and the molding method were similar to those adopted in Embodiment 8, that is, by the use of SF8 (the flint line produced by OHARA), molding was effected at a molding temperature of 520° C. and a molding pressure of 100 Kg/cm2 for one minute.
TABLE 16__________________________________________________________________________Conditions of deposition   Before heat treatment                                        After heat treatmentAssist gas                  Film  Surface                                        Film  SurfaceSamplemixture ratio        Extraction               Substrate                      H content                            density                                  roughness                                        density                                              roughness                                                    HardnessNo.  H2 /Ar        voltage (V)               temp (°C.)                      (atom %)                            (g/cm3)                                  (Rmax &#956;m)                                        (g/cm3)                                              (Rmax                                                    (kg/mm2)__________________________________________________________________________38   1/1     500    150    5     1.9   0.01  1.9   0.02  160039   H2 only        300    150    16    1.9   0.01  1.9   0.01  120040   1/1     400    300    8     1.7   0.02  1.7   0.02  200041   Ar only 300    300    0     2.0   0.02  1.6   0.02  120042   Ar only 250    500    0     1.5   0.04  1.1   0.08   10043   H2 only        1000   150    5     1.3   0.05  1.2   0.08   200__________________________________________________________________________
By the use of a mold base material similarto that used in Embodiment 8, a-C:H film was formed to a film thickness of 5000 Å on the molding surface in a similar manner to thereby make mold members. These mold members were heat-treated at 590° C. for two hours with the pressure reduced to 5×106 Torr, whereby the a-C:H film was changed into a hard carbon film, and this was used as Sample No. 44. What was not heat-treated was used as Sample No. 45. Glass was molded by the same apparatus and under the same conditions as those in Embodiment 8. Molding was effected 50 times on end with the mold members 38 and 39 mounted on the cylinders 138 and 140, and the amount of lead on the surface of each molded glass was detected by the X-ray diffraction method.
TABLE 17______________________________________     Pb peak intensity of     surface of molded glass (cps)       No. 44       No. 45Number      subjected to heat                    not subjected toof molding  treatment    heat treatment______________________________________1           0            3002           0            2804           0            1508           0            10015          0             4025          0             050          0             0______________________________________
The mold base material 26 was installed on the holder 25 and the internal pressure of the apparatus was reduced to 1×10-6 Torr, whereafter benzene and hydrogen gas were introduced into the apparatus to provide a desired pressure. The mold base material was heated and kept at a desired temperature, whereafter a magnetic field was applied thereto by the electromagnet 22, a bias voltage was applied to the mold base material and a microwave was introduced to thereby deposite films to 10000 Å each. The mold base material No. 46 was subjected to the heat treatment after a carbon film was made thereon. The conditions were : an N2 gas atmosphere of 1.2 atmospheric pressure (the partial pressure of oxygen being 5×10-3 Torr or less), 600° C. and the heating time of one hour.
TABLE 18______________________________________        No. 46  No. 47    No. 48______________________________________Conditions of depositionIntensity of magnetic          400       400       875field at the substrate(Gauss)Benzene/H2 ratio          3/1       3/1       1/9Pressure (Torr)          1 × 104                    5 × 104                              0.5Temperature of mold          300       500       600base material (°C.)Microwave power (W)          200       200       1000Bias of mold base          -500      -250      +50material (V)Film characteristicsbefore moldingCrystalline property          amorphous graphite  diamond(X-ray crystaldiffraction)H content      2         2         7(atom %)Spin density   1 × 1018                    5 × 1018                              1 × 1019(spin/cm3)          1.8       1.7       2.2Film density (g/cm3)Surface roughness          0.01      0.02      0.05Rmax (&#956;m)After moldingPeeling-off of film          &#8728;                    x         &#8728;Surface roughness          0.01      --        0.11Rmax (&#956;m)______________________________________
A molding test was carried out by the same apparatus and under the same conditions and by the use of the same glass as those in Embodiment 6. However, the molding temperature was 335° C., the molding pressure was 100 kg/cm2, the pressing time was one minute, and molding was effected 100 times on end.
With regard to the glass molded by the mold of No. 41, deterioration of the roughness of the surface and the accuracy of the surface was found after the 62and molding, and on the surface of the mold after the 100th molding, peeling-off of the film by 3 μm was found much particularly in the marginal portion.
As described above, by coating the mold base material with a-C:H film containing 40 atom% of hydrogen therein and having a film density of 1.5 g/cm3 or more, peeling-off of the film does not occur and the durability of the mold is improved. Also, by using a mold coated with a hard carbon film containing 0-5 atom% of hydrogen therein and having a spin density of 1×1018 spin/cm3 or less and a film density of 1.5 g/cm3 or more, there can be molded a good optical element which is low in reactiveness to glass and which does not require final polishing.
Further, said hard carbon film which is low in reactivity to glass is heat-treated and manufactured after a hard carbon film containing 5-40 atom% of hydrogen therein is made, whereby peeling-off of the film does not occur and the durability of the mold is improved and a stable film can be provided with good reproducibility by the heat treatment.
First, the mold base material 215 was worked into a predetermined shape, and the lens molding surface thereof was polished into a mirror surface. Subsequently, by the RF-PCVD apparatus, CH4 is supplied through the gas supply system 212 at a flow rate of 10 SCCM and at a gas pressure of 0.2 Torr, and 50 W was applied by the RF power of 13.56 MHz, and at room temperature, a film was deposited to a film thickness of 1000 Å on the mold base material (substrate), whereafter film deposition was effected while the substrate temperature was gradually increased. The final substrate temperature was 400° C., and the final film thickness was 5000 Å. The film (thickness 1000 Å) on the surface of contact with the mold base material was chemically analyzed with a result that the hydrogen content was about 50 atom% and the hardness of the film was 800 kg/mm2 in terms of Knoop hardness. On the other hand, the film on the surface of contact with glass was chemically analyzed with a result that the hydrogen content was about 20 atom%, the hardness or the film was 2000 kg/mm2 in terms of Knoop hardness, the roughness of the surface was Rmax 0.02 μm or less and the coefficient of friction was 0.2 or less and thus, the film obtained was a smooth film of high hardness.
After the mold in which the glass blank is placed is installed in the apparatus, the lid 52 of a vacuum chamber 51 is closed, and water flows into a water cooling pipe 70 and an electric current is supplied to heaters 58. At this time, valve for 66 and vent valves 68 nitrogen are closed and exhaust system valves 62, 63 and 64 are also closed. An oil rotating pump 61 is rotating at all times.
The valve 62 is opened to begin exhaust, and when the pressure becomes 10-2 Torr or less, the valve 62 is closed and the valve 66 is opened to thereby introduce nitrogen gas from a cylinder into the vacuum chamber. When a predetermined temperature is reached, an air cylinder 60 is operated to press the glass blank with a pressure of 10 kg/cm2 for five minutes. After the pressure is released, the glass blank is cooled to the transition point or below at a cooling speed of -5° C./min, whereafter it is cooled at a cooling speed of -20° C./min or higher, and when the temperature of the glass blank lowers to 200° C. or below, the valve 66 is closed and the vent valve 63 is opened to thereby introduce air into the vacuum chamber 51. The lid 52 is then opened and the upper mold keeper is removed, and then the molded article is taken out.
In the manner described above, a lens 204 shown in FIG. 14 was formed by the use of the optical glass SF14 of the flint line (the softening point Sp=586° C. and the transition point Tg=485 ° C.). The then conditions of deposition, i.e., the time-temperature relation, in the same temperature graph as the graph shown in FIG. 11.
TABLE 19__________________________________________________________________________                 Roughness of surface Rmax (&#956;m)Sample No. Coating      Base material                 Lens                    Mold (before molding)                                Mold (after molding)                                           Parting__________________________________________________________________________                                           Property49    None WC(90%) + Co(10%)                 0.04                    0.02        0.03       Good50    None SiC        -- 0.04        --         Fused51    SiC  WC(90%) + Co(10%)                 -- 0.02        --         Fused52    a-C:H      WC(90%) + Co(10%)                 0.03                    0.02        0.02       Good53    a-C:H      SiC        0.05                    0.04        0.04       Good__________________________________________________________________________
TABLE 20______________________________________    Roughness of surface Rmax (&#956;m)No.        Lens    Mold (after 200 times)______________________________________49         0.14    0.1552         0.03    0.0253         0.05    0.04______________________________________
Use was made of the RF-PCVD apparatus used in Embodiment 14, the mold base material (substrate) was provided on the RF electrode side, the degree of vacuum was 0.03 Torr, and the substrate temperature was room temperature and the flow rate of CH4 was 15 SCCM, and first, the RF power was 50 W and a film was formed to a film thickness of 1000 Å. This film had Knoop hardness 800 kg/mm2 and contained 60 atom% of hydrogen therein. Thereafter, the RF power was changed to 100 W, and a film was made to a film thickness of 4000 Å. This film had Knoop hardness 2200 kg/mm2 and contained about 10 atom% of hydrogen therein, and the roughness of the surface thereof was Rmax 0.03 μm or less and the coefficient of friction thereof was 0.2 or less. By the use of the mold on which this a-C:H film was formed, a press-molding test was carried out by the apparatus shown in FIG. 10.
Optical glass of the flint line (SF14, the softening point Sp=586° C. and the glass transition point Tg=485° C.) was roughly worked into a predetermined shape and dimensions, whereby there was obtained a blank for molding.
The glass blank was placed on the pallet 120, and then was placed in the position 120-1 in the taking-in replacement chamber 104, and the pallet in this position was pushed in the direction of arrow A by the rod 122 of the cylinder 124 and was conveyed to the position 120-2 in the molding chamber 106 beyond the gate valve 112, whereafter in the same manner, pallets were newly successively placed into the taking-in replacement chamber 104 at predetermined timing, and each time, the pallets were successively conveyed to positions 120-2→ . . . →20-8 in the molding chamber 106. In the meantime, in the heating zone 106 - 1, the glass blank was gradually heated by the heaters 128 and was rendered to the softening point or about at the position 120 - 4, whereafter it was conveyed to the press zone 106-2, where the cylinders 138 and 140 were operated to press the glass blank with a pressure of 10 kg/cm2 for five minutes by the upper mold member 130 and the lower mold member 132, whereafter the pressure was released and the glass blank was cooled to the glass transition point or below, and thereafter the cylinders 138 and 140 were operated to part the upper mold member 130 and the lower mold member 132 from the molded glass article. During this press, said pallet was utilized as a side mold member for molding. Thereafter, the molded glass article was gradually cooled in the gradually cooling zone 106-3. The molding chamber 106 was dilled with inert gas.
The pallet which arrived at the position 120-8 in the molding chamber 106 was then conveyed to the position 120-9 in the evaporation chamber 108 beyond the gate valve 114. Usually, vacuum evaporation ms effected here but in the present embodiment, such evaporation was not effected. In the next cycle of conveyance, the pallet was conveyed to the position 120-10 in the taking-out replacement chamber 110 beyond the gate valve 116. During the next cycle of conveyance, the cylinder 150 was operated and the molded glass article was taken out of the molding apparatus 102 by the rod 148.
TABLE 21__________________________________________________________________________              Roughness of surface Rmax (&#956;m)                 Mold     Mold    PartingNo.   Coating   Base material              Lens                 (before molding)                          (after molding)                                  Property__________________________________________________________________________54 None WC(90%) + Co(10%)              0.04                 0.02     0.03    Good55 None SiC        -- 0.04     --      Fused56 SiC  WC(90%) + Co(10%)              -- 0.02     --      Fused57 a-C:H   WC(90%) + Co(10%)              0.03                 0.03     0.03    Good58 a-C:H   SiC        0.05                 0.04     0.04    Good__________________________________________________________________________
TABLE 22______________________________________Numberof            Roughness of surface Rmax (&#956;m),No.    molding    Lens        Mold______________________________________54      200       0.14        0.15  1000       0.20        0.21  5000       0.23        0.24  10000      0.26        0.2757      200       0.03        0.03  1000       0.03        0.03  5000       0.03        0.03  10000      0.04        0.0358      200       0.05        0.04  1000       0.05        0.04.  5000       0.05        0.04  10000      0.05        0.05______________________________________
By a method similar to Embodiment 15, a film was first formed to a film thickness 1000 Å at RF power 50 W. The RF power was then changed to 80 W and the mold base material (substrate) was heated to 300° C., whereafter the film was further formed to 6000 Å. This film had Knoop hardness of 2400 kg/mm2, contained 20 atom% of hydrogen therein, and had surface roughness of Rmax 0.02 μm or less and a coefficient of friction of 0.2 or less. Also, by the analysis in the direction of depth by an ion microanalyzer, it was confirmed that the hydrogen content in the film on that side contacting with the mold base material was 60 atom%, that hydrogen content in the film on the surface side was 20 atom% and that two layers of films were formed by the difference in the hydrogen content. By the use of this mold, a molding test and evaluation similar to those in Embodiment 1 were effected with a result that a mold equal to that of Embodiment 14 was obtained.
a-C:H film in which the hydrogen content exceeds 40 atom% is softer than a film in which the amount of hydrogen content is 5-40 atom% and therefore, when a film containing 5-40 atom% of hydrogen therein is formed on the a-C:H film, the film thickness thereof exceeds 5000 Å and even if the internal stress therein becomes great, the stress can be absorbed in this soft a-C:H film to reduce the stress of the entire film, whereby the adhesion/adherence thereof with respect to the mold base material is improved. Also, not only the stress but also the distortion in the film due to the difference in the coefficient of thermal expansion and to the mechanical deformation resulting from molding can be alleviated.
Subsequently, the gases shown in Table 23 above were introduced from the gas inlet port 27, the pressure was rendered to 5×10-2 Torr, and under constant conditions of microwave power 600 W and the mold surface temperature 300° C., film making was effected for one hour, whereby molds Nos. 59-71 were obtained.
TABLE 24______________________________________Mold   Element analysis value                       Knoop hardnessNo.    C      H      N      O       (kg/mm2)______________________________________59     1.5    1      1,000  --      180060     1.5    1      200    --      175061     19     1      20,000 --      210062     5      3      100    --      150063     19     1      300    --      200064     4      3      --     1,000   200065     1.5    1      --     30,000  165066     2      1      --     500     185067     2      1      --     100     190068     2      1.3    100    200     200069     1.5    1      100    3,000   195070     1.5    1      2,000  100     175071     1.5    1      --     --       700______________________________________
The valve 62 is opened to begin exhaust, and when the pressure becomes 10-2 Torr or less, the valve 62 is closed, and the valve 66 is opened to introduce nitrogen gas from a cylinder into the vacuum chamber. When a predetermined temperature is reached, the air cylinder 60 is operated to press the glass blank with a pressure of 10 kg/cm2 for five minutes. After the pressure is released, cooling is effected at a cooling speed of -5° C./min until the transition point or below is reached, whereafter cooling is effected at a speed of -20° C./min or higher, and when the temperature falls to 200° C. or below, the valve 66 is closed and the leak valve 63 is opened to introduce air into the vacuum chamber 51. The lid 52 is then opened and the upper mold keeper is removed, whereafter the molded article is taken out.
In the manner described above, a lens 4 was molded by the use of optical glass SF14 of the flint line (the softening point Sp=586° C. and the transition point Tg=485° C.). The condition of deposition at this time, i.e., the time-temperature relation, is the same as that shown in FIG. 11.
TABLE 25______________________________________Mold  Roughness of surface Rmax (&#956;m)No.   Lens   Mold (before molding)                        Mold (after molding)______________________________________59    0.03   0.03            0.0360    0.03   0.03            0.0361    0.03   0.03            0.0362    0.03   0.03            0.0363    0.03   0.03            0.0364    0.03   0.03            0.0365    0.03   0.03            0.0366    0.03   0.03            0.0367    0.03   0.03            0.0368    0.03   0.03            0.0369    0.03   0.03            0.0370    0.03   0.03            0.0371    0.10   0.05            0.07______________________________________
Optical glass of the flint line (SF14, the softening point Sp=586° C. and the glass transition point Tg=485° C.) was roughly worked into a predetermined shape and dimensions, whereby a blank for molding was obtained.
The glass blank was placed on the pallet 120 and placed in the position 120-1 in the taking-in replacement chamber 104, and the pallet in this position was pushed in the direction of arrow A by the rod 122 of the cylinder 124 and conveyed to the position 120-2 in the molding chamber 106 beyond the gate valve 112, whereafter in the same manner, pallets were newly successively placed into the taking-in replacement chamber 104 at predetermined timing, and each time, the pallets were successively conveyed to the positions 120-2 →. . . → 120-8 in the molding chamber 106. In the meantime, in the heating zone 106-1, the glass blank was gradually heated by the heaters 128 and rendered to the softening point or above at the position 120-4, whereafter it was conveyed to the press zone 106-2, where the cylinders 138 and 140 were operated to press the glass blank with a pressure of 10 kg/cm2 for five minutes by the upper mold member 130 and the lower mold member 132, whereafter the pressure was released and the glass blank was cooled to the glass transition point or below, whereafter the cylinders 138 and 140 were operated to part the upper mold member 130 and the lower mold member 132 from the molded glass article. During this pressing, said pallet was utilized as a side mold member for molding. Thereafter, in the gradually cooling zone 106-3, the molded glass article was gradually cooled. The molding chamber 106 was filled with inert gas.
The pallet which arrived at the position 120-8 in the molding chamber 106 was then conveyed to the position 120-9 in the evaporation chamber 10; beyond the gate valve 114. Usually, vacuum evaporation is effected here, but in the present embodiment, such evaporation was not effected. In the next cycle of conveyance, the pallet was conveyed to the position 120-10 in the taking-out replacement chamber 110 beyond the gate valve 116. During the next cycle of conveyance, the cylinder 150 was operated and the molded glass article was taken out of the molding apparatus 102 by the rod 148.
In the same manner as in Embodiment 17, by the use of the apparatus shown in FIG. 6 and by the ECR-PCVD method, the surface of a mold base material comprising WC 90% and Co 10% was coated with a-C:H film. However, the microwave power 600 W as changed to 700 W, and the magnitude 2000 gauss of the magnetic field in the microwave introduction port was changed to 2500 gauss. The kinds and flow rates of gases used for deposition are shown in Table 26 below.
TABLE 26______________________________________MoldNo.   CH4        CH3 OH                 He  Ne  Ar  Xe   Kr  NH3                                           CO   H2______________________________________72    10              273    10                  2                          574    10                      275    10                          276    10                               277           10       2                    1         578                    2                         10   579                                2        1    10______________________________________ (Unit: SCCM)
TABLE 27__________________________________________________________________________Mold No. C H N   O  He  Ne Ar Xe Kr Hardness (kg/mm2)__________________________________________________________________________72    2 1        500             1,50073    1.5   1            900         1,20074    3 1               4,000    2,50075    1.5   1                  1100  1,30076    1.5   1                     100                            1,40077    2 1 10,000 500             1,70078    3 1     1,000            3,000           2,60079    2 1  1,000         1,000     1,000    1, 800__________________________________________________________________________ (The contents of C and H are in atom ratio, and the others are in atom ppm.)
Subsequently, by the ion beam deposition method shown in FIG. 16, the mold was coated with a film in the same manner as in the above-described example. In FIG. 16, the reference numeral 322 designates a vacuum chamber, the reference numerals 323 and 323' denote two ion gun, the reference numerals 324 and 324' designate ionization chambers, the reference numerals 325 and 325' denote ion beam extractive grids, the reference numerals 326 and 326' designate gas introduction ports, the reference numeral 327 denotes a mold base material, and the reference numeral 328 designates a mold holder.
From the gas inlet port 326, a mixture of carbon-containing gas and hydrogen is introduced and ionized to create an ion beam, and in the gas inlet port 326', inert gas atoms are ionized and drawn our as an ion beam, and a film is formed on the mold base material 327.
The back pressure of the vacuum chamber was 2×10-5 Torr, methane, hydrogen and helium were used as the film-making gases, and the gas flow rates thereof were fixed to 5 SCCM. At this time, the pressure became 3×10-4 Torr.
TABLE 28______________________________________Acceleration voltage Ion beam of               SubstrateMold  methane and    Ion beam of                           temperatureNo.   hydrogen (kv)  helium (kv)                           (°C.)______________________________________80    0.5            0.5         8081    0.8            0.5        10082    1.0            0.5        12083    5.0            0.5        15084    0.5            2          10085    0.8            2          13086    1.0            2          15087    5.0            2          180______________________________________
TABLE 29______________________________________Mold No.   C     H       He   Hardness (kg/mm2)______________________________________80         1     1       1,000                         150081         1     1       1,000                         140082         1     0.8     1,000                         180083         1     0.7     1,000                         185084         1     0.6     1,000                         190085         1     0.6     1,000                         200086         1     0.4     1,000                         230087         1     0.2     1,000                         2900______________________________________ (The contents of C and H are in atom ratio, and the amount of He is in atom ppm.)
The roughness of the surfaces of the molded lenses and the roughness of the surfaces of the molds before and after molding were measured. The result is shown in Table 30 below.
TABLE 30______________________________________Roughness of surface Rmax (&#956;m)Mold          Mold         Mold-     PartingNo.   Lens    (before molding)                      (after molding)                                property______________________________________72    0.03    0.03         0.03      Good73    0.03    0.03         0.03      "74    0.03    0.03         0.03      "75    0.03    0.03         0.03      "76    0.03    0.03         0.03      "77    0.03    0.03         0.03      "78    0.03    0.03         0.03      "79    0.03    0.03         0.03      "80    0.03    0.03         0.03      "81    0.03    0.03         0.03      "82    0.03    0.03         0.03      "83    0.03    0.03         0.03      "84    0.03    0.03         0.03      "85    0.03    0.03         0.03      "86    0.03    0.03         0.03      "87    0.03    0.03         0.03      "______________________________________
When a-C:H film is to be formed, the mold base material 337 having its surface cleaned by an organic solvent is installed on a holder 336, and the air is exhausted from an exhaust port 342 to thereby render the interior of a chamber 335 vacuum. The mold base material 337 is heated to 300° C., and source gas CH4 +CF4 is introduced at the ratio of CH4 /CH4 =2 from a gas inlet port 338. H2 gas is introduced by 10 SCCM from an introduction port 339.
RF power 300 W and substrate bias -300 V were applied, the pressure was kept at 2×10-2 Torr and discharge was effected. The substrate temperature was held at 150° C. and a film of 0.5 μm was deposited. 30 atom% of hydrogen was contained in the thus produced film a-C:H:F and C-F bonding was confirmed by the surface analysis using ESCA.
In the same manner as in Embodiment 19, by the use of the apparatus of FIG. 7, mixture gas of Ar/H2 =1 was introduced from the inlet port 339, CH4 gas was introduced from the inlet port 338, RF power 300 W and substrate bias -500 V were applied and a film of 0.5 μm was deposited at a substrate temperature 200° C. Thereafter, CF4 gas was introduced from the introduction port 339 and discharge was effected at RF power 200 W and substrate bias 0 V.
The thus produced film contained 25 atom% of hydrogen therein and C-F bonding was confirmed by ESCA.
TABLE 31______________________________________No.     Coating Material                  Base material______________________________________88      None           WC(90%) + Co(10%)89      None           SiC90      SiC            WC(90%) + Co(10%)91      a-C:H:F        WC(90%) + Co(10%)92      a-C:H:F        SiC93      a-C:H:F        WC(90%) + Co(10%)______________________________________
TABLE 32__________________________________________________________________________              Roughness of surface Rmax (&#956;m)                 Mold     Mold    PartingNo.   Coating   Base material              lens                 (before molding)                          (after molding)                                  property__________________________________________________________________________88 None WC(90%) + Co(10%)              0.04                 0.02     0.03    Good89 None SiC        -- 0.04     --      Fused90 SiC  WC(90%) + Co(10%)              -- 0.02     --      Fused91 a-C:H:F   WC(90%) + Co(10%)              0.03                 0.02     0.02    Cood92 a-C:H:F   SiC        0.05                 0.04     0.04    Good93 a-C:H:F   WC(90%) + Co(10%)              0.03                 0.03     0.03    Good__________________________________________________________________________
Subsequently, with respect to Nos. 88, 91 92 and 93 which did not cause fusion, press-molding was effected 10,000 times on end by the use of the same mold members and by the apparatus shown in FIG. 10. The roughness of the molding surfaces of the mold members at this time and the roughness of the optical surfaces of the molded optical elements are shown in Table 33 below.
TABLE 33______________________________________Number         Roughness of surface Rmax (&#956;m)No.    of molding  Lens        Mold______________________________________88      200        0.24        0.15   1000       0.20        0.21  10000       0.26        0.2791      200        0.03        0.03   1000       0.03        0.03  10000       0.04        0.0392      200        0.04        0.04   1000       0.05        0.04  10000       0.05        0.0493      200        0.03        0.03   1000       0.03        0.03  10000       0.03        0.03______________________________________
FIG. 18 shows the state before the press-molding of an optical element, and FIG. 19 shows the state after the molding of the optical element. In FIG. 18, the reference numeral 401 designates a mold base material, the reference numerals 402 and 405 denote a-C:H film and an intermediate layer formed on the molding surfaces of the mold base material which contact with a glass blank, and the reference numeral 403 designates the glass blank; and in FIG. 19, the reference numeral 404 denotes the optical element. By press-molding the glass blank 403 placed between the molds as shown in FIG. 18, the optical element 404 such as a lens is molded as shown in FIG. 19.
WC(90%)+Co(10%) was used as the mold base material. The internal pressure of the vacuum chamber 411 was reduced to 1×10-6 Torr, whereafter Ar gas was introduced from the gas introduction port 413 into the ion gun 412 and was thereby made into an Ar+ ion beam, which was applied to the surface of the substrate (base material) 414 to clean the same.
Thereafter, the intermediate layer was produced. Methane gas was introduced from the gas introduction port into the ion gun, and an acceleration voltage 100 V and an ion current 0.05 mA/cm2 were applied to thereby make the gas into an ion beam while, on the other hand, an electron beam (9 KV, 1A) was applied from the electron gun 417 to the tungsten 416 of high purity (99.99%) and at the same time, evaporation was effected. The substrate temperature was held at 300° C., and the pressure in the vacuum chamber was 4×10-4 Torr. The produced intermediate layer had a thickness of 1,000 Å.
The a-C:H film was then formed. Mixture gas of a ratio of CH4 /H2 =1/2 was introduced into the ion gun, an acceleration voltage 600 V was applied, and an ion beam of ion current 0.85 mA/cm2 was applied onto the substrate (base material+intermediate layer) held at a substrate temperature 150° C.
The pressure was 2×10-4 Torr, and the film thickness of the a-C:H film was 5,000 Å.
TABLE 34______________________________________No.     Coating material                   Base material______________________________________94      None            WC(90%) + Co(10%)95      None            SiC96      SiC             WC(90%) + Co(10%)97      a-C:H (having   WC(90%) + Co(10%)   intermediate layer)______________________________________
The mold in which the glass blank is placed is installed in the apparatus, and then the lid 52 of the vacuum chamber 51 is closed, and water flows into the water cooling pipe 70 and an electric current is supplied to the heaters 58. At this time, the valve 66 for nitrogen gas and vent valve 68 are closed and the exhaust system valves 62, 63 and 64 are also closed. The oil rotating pump 61 is rotating at all times.
The valve 62 is opened to begin exhaust and when the pressure reaches 10-2 Torr or less, the valve 62 is closed and the valve 66 is opened to introduce nitrogen gas from a cylinder into the vacuum chamber. When a predetermined temperature is reached, the air cylinder 60 is operated to press the glass blank with a pressure of 10 kg/cm2 for five minutes. After the pressure is released, cooling is effected at a cooling speed of -5° C./min until the transition point or below is reached, whereafter cooling is effected at a speed of -20° C./min or higher, and when the temperature falls to 200° C. or below, the valve 66 is closed and the vent valve 63 is opened to introduce air into the vacuum chamber 51. The lid 52 is then opened, the upper mold keeper is removed and the molded article is taken out.
In the manner described above, the lens 404 shown in FIG. 19 was molded by the use of optical glass SF148 of the flint line (the softening point Sp=586° C. and the transition point Tg=485° C.). The condition of molding at this time, i.e., the time-temperature relation, is the same as FIG. 11.
TABLE 35__________________________________________________________________________                Roughness of surface Rmax (&#956;m)                   Mold     Mold    PartingNo.   Coating     Base material                Lens                   (before molding)                            (after molding)                                    property__________________________________________________________________________94 None   WC(90%) + Co(10%)                0.04                   0.02     0.03    Good95 None   SiC        -- 0.04     --      Fused96 SiC    WC(90%) + Co(10%)                -- 0.02     --      Fused97 a-C:H  WC(90%) + Co(10%)                0.03                   0.02     0.02    Good   (having   intermediate   layer)__________________________________________________________________________
TABLE 36______________________________________    Roughness of surface Rmax (&#956;m)No.        Lens    Mold (after 200 times)______________________________________94         0.14    0.1597         0.03    0.02______________________________________
Use was made of a mold base material and an apparatus similar to those used in Embodiment 21. In a similar manner, cleaning of the substrate was effected, whereafter the pressure and the substrate temperature were kept at 4×10-4 Torr and 150° C., respectively, and methane gas was introduced into the ion gun and an ion beam was applied and at the same time, evaporation of tungsten was effected. The then acceleration voltage of the ion gun and the current value of the ion beam for deposition were varied as shown in FIG. 21, and the intermediate layer and the a-C:H layer were continuously formed into a film of 6,000 Å as a whole.
The pallet which arrived at the position 120-8 in the molding chamber 106 was then conveyed to the position 120-9 in the deposition chamber 1()8 beyond the gate valve 114. Usually, vacuum evaporation is effected here, but in the present embodiment, such evaporation was not effected. In the next cycle of conveyance, the pallet was conveyed to the position 120-10 in the taking-out replacement chamber 110 beyond the gate valve 116. During the next cycle of conveyance, one cylinder 150 was operated and the molded glass article was taken out of the molding apparatus 102 by the rod 148.
TABLE 37__________________________________________________________________________                Roughness of surface Rmax (&#956;m)                   Mold     Mold    PartingNo.   Coating     Base material                Lens                   (before molding)                            (after molding)                                    property__________________________________________________________________________ 98   None   WC(90%) + Co(10%)                0.04                   0.02     0.03    Good 99   None   SiC        -- 0.04     --      Fused100   SiC    WC(90%) + Co(10%)                -- 0.02     --      Fused101   a-C:H  WC(90%) + Co(10%)                0.03                   0.03     0.03    Good   (having   intermediate   layer)__________________________________________________________________________
TABLE 38______________________________________Number         Roughness of surface Rmax (&#956;m)No.    of molding  Lens        Mold______________________________________ 98     200        0.14        0.15  1000        0.20        0.21  5000        0.23        0.24  10000       0.26        0.27101     200        0.03        0.03  1000        0.03        0.03  5000        0.03        0.03  10000       0.04        0.03______________________________________
By the same mold base material as that used in Embodiment 21 and in a similar manner, the substrate (base material) 424 was cleaned by Ar+ ion beam. Thereafter, methane gas at 4×10-3 Torr was introduced from the gas inlet port 423 into the ion gun 422 and an ion beam was applied to the substrate at an acceleration voltage 100 V and ion current 0.05 mA/cm2. At the same time, argon gas at 4×10-4 Torr was introduced from the gas inlet port 423' into the vicinity of the tungsten 426 of high purity 99.99%, and an RF of 13.56 MHz and output 1 KW was applied to the tungsten, whereby sputter deposition of the tungsten was effected. The substrate temperature was 150° C. and an intermediate layer was formed to a thickness of 1,000 Å.
Subsequently, a-C:H film was deposited in the same manner as in Embodiment 21, and the film thickness of the whole including the intermediate layer was rendered to 6,000 Å.
The same mold base material apparatus as that used in Embodiment 23 was used and cleaning of the substrate was effected in a similar manner. Thereafter, methane gas was introduced into the ion gun and made into an ion beam, which was applied, and at the same time, sputtering of the tungsten was effected, but the RF output power and the ion gun acceleration voltage were varied as shown in FIG. 23, and a film was made continuously. The thickness of the entire film was 5,500 Å. The substrate temperature was 150° C., the Ar gas was at 4×10-3 Torr→0 Torr, the RF (1356 MHz) output power was 1 KW→0 W, the methane gas was at 4×10-4 Torr, and the acceleration voltage was 50 V→500 V.
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W. Smith, "Optical Properties and Local Atomic Bonding In Hydrogenated Amorphous Carbon And Silicon-Carbon Alloys," Materials Science Forum, vols. 52 and 53, 1989, pp. 323-340.2 *F. W. Smith, Optical Properties and Local Atomic Bonding In Hydrogenated Amorphous Carbon And Silicon Carbon Alloys, Materials Science Forum, vols. 52 and 53, 1989, pp. 323 340.3 *Journal of Non Crystalline Solids 35 & 36 (1980), pp. 543 548, N. Wada et al., Diamond Like 3 Fold Coordinated Amorphous Carbon. 1980.4Journal of Non-Crystalline Solids 35 & 36 (1980), pp. 543-548, N. Wada et al., "Diamond-Like" 3-Fold Coordinated Amorphous Carbon. 1980.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5540958 *Dec 14, 1994Jul 30, 1996Vlsi Technology, Inc.Method of making microscope probe tipsUS6118590 *Mar 17, 1999Sep 12, 2000Olympus Optical Co., Ltd.Small-type imaging optical systemUS6284315Jan 14, 2000Sep 4, 2001Aurburn UniversityMethod of polishing diamond filmsUS6558742Feb 10, 2000May 6, 2003Auburn UniversityMethod of hot-filament chemical vapor deposition of diamondUS6928838 *Sep 16, 2002Aug 16, 2005Toshiba Machine Co., Ltd.Apparatus and method for forming silica glass elementsUS7273204 *Mar 8, 2006Sep 25, 2007Hon Hai Precision Industry Co., Ltd.Mold for forming optical lens and method for manufacturing such moldUS7313930 *Dec 3, 2003Jan 1, 2008Fuji Electric Device Technology Co., LtdMethod and apparatus for manufacturing glass substrate for storage mediumUS7323219 *Mar 14, 2003Jan 29, 2008Teer Coatings LtdApparatus and method for applying diamond-like carbon coatingsUS7377477 *Feb 11, 2005May 27, 2008Diamond Innovations, Inc.Product forming molds and methods to manufacture sameUS7562858 *Mar 16, 2006Jul 21, 2009Diamond Innovations, Inc.Wear and texture coatings for components used in manufacturing glass light bulbsUS20030056542 *Sep 16, 2002Mar 27, 2003Hiroshi MurakoshiApparatus and method for forming silica glass elementsUS20040134232 *Dec 3, 2003Jul 15, 2004Fuji Electric Device Technology Co., Ltd.Method and apparatus for manufacturing glass substrate for storage medium, glass substrate for storage medium, and storage mediumUS20050126486 *Mar 14, 2003Jun 16, 2005Denis TeerApparatus and method for applying diamond-like carbon coatingsUS20050173834 *Feb 11, 2005Aug 11, 2005Diamond Innovations, Inc.Product forming molds and methods to manufacture sameUS20060208151 *Mar 16, 2006Sep 21, 2006Diamond Innovations, Inc.Wear and texture coatings for components used in manufacturing glass light bulbsUS20060261241 *Mar 8, 2006Nov 23, 2006Ga-Lane ChenMold for forming optical lens and method for manufacturing such moldWO2005077114A3 *Feb 11, 2005Oct 12, 2006Diamond Innovations IncProduct forming molds and methods to manufacture same* Cited by examinerClassifications U.S. Classification65/26, 427/372.2, 427/577, 65/374.1, 427/249.1, 65/286, 425/808, 106/38.28, 65/374.15, 427/135, 65/305International ClassificationC23C16/26, C03B40/02, C22C29/08, C04B41/85, C23C14/06, C04B41/50, C03B11/08Cooperative ClassificationY10S425/808, C22C29/08, C03B2215/24, C03B40/02, C04B2111/00939, C23C14/0605, C04B41/5001, C04B41/009, C03B2215/12, C03B11/086, C23C16/26, C04B41/85, C03B2215/34European ClassificationC04B41/00V, C03B11/08C2, C23C14/06B, C23C16/26, C04B41/50B, C04B41/85, C03B40/02, C22C29/08Legal EventsDateCodeEventDescriptionMay 9, 1995CCCertificate of correctionMay 28, 1998FPAYFee paymentYear of fee payment: 4Jun 20, 2002FPAYFee paymentYear of fee payment: 8Aug 2, 2006REMIMaintenance fee reminder mailedJan 17, 2007LAPSLapse for failure to pay maintenance feesMar 13, 2007FPExpired due to failure to pay maintenance feeEffective date: 20070117RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services