Background Art In the related art, there is a microplate formed by adhering a plate having a light transmitting property on one of the surfaces of a plastic resin plate having a metal plate sandwiched therein. In such a microplate, since the metal plate has a good thermal conductivity, it is easy to heat or cool the samples stored in the microplate or to provide the respective samples on the identical microplate temperature gradient, and is preferable in observation of samples based on a PCR (Polymerase Chain Reaction) method.

An example of the structure of such a microplate in the related art is shown in Fig. 6.

In Fig. 6, (a) is a top view of a microplate 1, (b) isabottomviewofthemicroplatel, (c) is anenlarged top view of the microplate 1, and (d) is a cross-sectional view of the microplate 1 taken along an alternate long and short dash line shown as C-C in (c). In Figs. 6 (a) and (b), an outer frame which does not relate to the present invention is omitted.

The microplate 1 includes cylindrical wells 2 arranged in rows and columns connected in a rectangular shape at regular intervals, as shown in Fig. 6 (a) and (b).

Also, as shown in Fig. 6 (d), the microplate 1 is formed by adhering a cover glass 4 having light transmitting property to one of the surfaces of a resin plate 3.

A resin plate 3 is formed of resin 5, which is a <BR> <BR> plasticmaterial. Intheresinplate3, thereisprovided an aluminum plate 6, and the aluminum plate 6 covered by resin 5 constitutes the resin plate 3. The aluminum plate 6 is formed with round holes of larger diameter than the inner diameter of the well 2 at intervals corresponding to the arrangement of the wells 2 so as to prevent the aluminum plate 6 from being exposed inside

the well 2 and coming into direct contact with the samples.

In other words, the resin plate 3 is a plate shape member including the wells 2 connected with each other at the positions of the round holes provided on the aluminum plate 6. Since one side of the openings of the wells 2 is covered by a cover glass 4, the samples stored in the well 2 may be retained.

Referring now to Fig. 7, an example of usage of the microplate 1 will be described.

In Fig. 7, sample containing liquid 7 in which a sample is mixed is injected into the wells 2 on the microplate 1. When performing fluorescent observation of this sample using, for example, an inverted fluorescent microscope, an objective lens 8 is arranged below the cover glass 4, and observation of the sample is carried out through the cover glass 4. Pure water 9 is injected between the objective lens 8 and the cover glass 4 when the objective lens 8 is an immersion lens.

The microplate 1 having the aluminum plate 6 sandwiched therein may be fabricated, for example, by injecting and molding plastic resin in a forming die in which the aluminum plate 6 is set to form the resin plate 3, and then adhering the cover glass 4 on one side of the surfaces of the resin plate 3.

A microplate formed with a metal plate sandwiched

by plastic resin is disclosed, for example, in this patent document.

Pamphletof International PublicationNO. 01/94018 A gate for injecting plastic resin into a cavity of a forming die for the above-described resin plate 3 is arranged, for example, in the vicinity of the center of the surface of the resin plate 3.

When injection molding of the resin plate 3 is performed using such a forming die, since the cooling speed of resin 5 is higher on an outer peripheral portion of the surface of the resin plate 3 than the center portion thereof, hardening of resin 5 starts earlier at the outer peripheral portion. Then, since resin 5 at the center of the surface of the resin plate 3 is pulled toward the outer peripheral portion due to shrinkage of resin 5 upon hardening, the outer peripheral portion of the surface of the resin plate 3 is mounded with respect to the center portion thereof, and consequently, a recess called"molding sink"is formed at the center portion of the pi ate surface, and hence the flatness of the surface of the resin plate 3 is deteriorated.

Also, deformation of the resin plate 3 due to uneven shrinkage due to hardening of plastic resin may occur on the front and back surfaces of the resin plate 3.

In the above-described forming die, since the gate for

injecting resin 5 is disposed at the above-described position, the cooling speed on the surface of the resin plate 3 formed of resin 5 is different between the surface on the side provided with the gate and the surface on the opposite side. Therefore, warping may occur on the resin plate 3 because hardening of plastic resin does not proceed uniformly on both surfaces of the plate, and hence the flatness of the plate surface may be deteriorated.

The warping may also occur when the density of resin 5 injected in the forming die is significantly different depending on the position of the forming die.

On the other hand, in the above-described microplate 1, the thickness of the cover glass 4 to be adhered to the resin plate 3 is generally very thin, and it may be broken when being deformed. Therefore, highly precise flatness is required for the adhesion surface of the light transmissible plate of the plastic resin plate.

The above described problems may occur irrespective of the presence of the metal plate, as far as the microplate is formed by injection molding of the plastic resin.

In view of the problems described above, a problem to be solved is to improve the flatness of the surface

of the plastic resin plate and is formed into a microplate by adhering a light transmissible plate, to be adhered to the light transmissible plate.

Disclosure of Invention A microplate according to the present invention is based on the premise that a plurality of wells for storing samples to be observed are provided.

A microplate according to a first embodiment of the present invention is characterized in that the aforementioned wells are formed by adhering a light transmissible plate having alight transmitting property so as to cover openings of through-holes formed on a resin plate formed of plastic resin on one side, and the aforementioned resin plate comprises a surface rougher than the surface to be adhered to the aforementioned light transmissible plate.

In order to roughen the surface of the resin plate, a transfer surface of a forming die to be used for injection molding the resin plate corresponding to this specific surface is formed to have a rough surface. When the transfer surface of the forming die is roughened, plastic resin cannot be filled into the valley portions of the rough transfer surface having concavities and convexities sufficiently, and hence friction generated

between the transfer surface and plastic resin is lowered.

Consequently, molding sink may easily occur at these points. When expressing the fact that molding sink may easily occur at these points in other words, molding sink can hardly occur on the surface of the resin plate to be adhered to the light transmissible plate. That is, the resin plate as described above is improved in flatness of the surface to be adhered to the light transmissible plate.

In the microplate according to the aforementioned first embodiment, the aforementioned rough surface may be a side surface of a cylinder formed of the aforementioned plastic resin, which defines the aforementioned through-hole.

Since the side surface is not a surface to be adhered to the light transmissible plate, flatness of the surface to be adhered to the light transmissible plate is improved by roughening the side surface.

In the microplate according to the aforementioned first embodiment of the present invention, the rough surface described above may be a surface of the resin plate having openings which are not covered by the aforementioned light transmissible plate.

Since this surface of the resin plate is neither a surface to be adhered to the light transmissible plate,

flatness of the surface to be adhered to the light transmissible plate is improved by roughening this surface.

In the microplate according to the aforementioned first embodiment of the present invention, the aforementioned resin plate is formed by covering a metal plate with plastic resin, and the aforementioned through-hole may be extended through the metal plate.

Withthemicroplateconfiguredasdescribedabove, heating and cooling of the samples in a state in which the samples are stored in the microplate, or providing temperature gradient the respective samples on the identical microplate may easily be performed.

A microplate according to a second embodiment of the present invention is characterized in that wells are formed by adhering a light transmissible plate having a light transmitting property so as to cover openings of through-holes extending through the resin plate together with the metal plate on one side, the aforementioned through-holes are formed on the resin plate formed by covering the aforementioned metal plate with plastic resin, and in that the surface of the aforementioned metal plate having openings covered with the aforementioned light transmissible plate is rougher than the surface to be adhered to the aforementioned

light transmissible plate.

When the surface of the metal plate is roughened, plastic resin cannot be filled into the valley portions of the rough surface having concavities and convexities sufficiently, and hence friction generated between the rough surface and the plastic resin is lowered.

Consequently, molding sink may easily occur. When expressing the fact that molding sink of plastic resin may easily occur on the surface of the metal plate which comes into contact with the surface having openings to be covered by the light transmissible plate in other words, molding sink can hardly occur on the surface of the resin plate having openings to be covered by the lighttransmissibleplatecorrespondingly. Thatis, the resin plate as described above is improved in flatness of the surface to be adhered to the light transmissible plate.

In the microplate according to the aforementioned second embodiment of the present invention, the surface of the aforementioned metal plate having openings which are not covered by the light transmissible plate may have the same roughness with the surface having openings to be covered by the aforementioned light transmissible plate.

By equalizing the roughness of both surfaces of

the metal plate, molding sink of plastic resin on the surface which comes into contact with the metal plate occurs uniformly on both surfaces thereof, and hence warping of the resin plate due to molding sink may be alleviated.

A microplate according to a third embodiment of the present invention is characterized in that wells are formed by adhering a light transmissible plate having a light transmitting property so as to cover openings of through-holes provided on a resin plate formed of plastic resin, and in that an outer peripheral portion of the surface of the aforementioned resin plate on which the aforementioned light transmissible plate is adhered is rougher than a center portion thereof.

As described above, since the cooling speed at the outer peripheral portion of the resin plate is faster than the center portion thereof, molding sink can hardly occurs at the outer peripheral portion thereof. On the other hand, as described above, when a transfer surface of a forming die to be used for injection molding of the resin plate for roughening the surface of the resin plate is roughened, molding sink tends to occur at the roughened portion of the transfer surface. Therefore, when expressing the fact that the outer peripheral portion of the corresponding surface of the resin plate

is roughened in other words, occurrence of molding sink is uniformized between the outer peripheral portion and the center portion of the corresponding surface. That is, the resin plate as described above is improved in flatness of the surface to be adhered to the light transmissible plate.

In the microplate according to the aforementioned third embodiment, that the outer peripheral portion of the surface of the aforementioned resin plate on which the aforementioned light transmissible plate is not adhered is also formed to be rougher than the center portion of the corresponding surface.

When expressing the fact that the outer peripheral portions of both surfaces of the resinplate are roughened in other words, occurrence of molding sink is uniformized at the outer peripheral portions and the center portions on both surfaces, and hence warping of the resin plate due to molding sink may be alleviated.

In the microplate according to the aforementioned third embodiment of the present invention, the aforementioned wells are formed by adhering the aforementioned light transmissible plate on the end surfaces of the cylinders forming the aforementioned through-holes, and hence the end surfaces of the aforementioned cylinders formed on the outer peripheral

portion of the aforementioned resin plate may be formed to be rougher than the end surfaces thereof provided at the center portion of the aforementioned resin plate.

The end surface of the cylinder is a surface to be adhered directly to the light transmissible plate, and flatness of the surface to be adhered to the light transmissible plate is improved by roughening this end surface.

In this structure, the aforementioned cylinders are arranged at regular intervals on the aforementioned resin plate in the vertical and lateral directions into a square shape, and the end surfaces of the cylinders which are disposed at four corners of those disposed into a square shape may be formed to be rougher than the end surfaces of other cylinders.

In the case where the aforementioned cylinders are arranged as described above on the resin plate, the cylinders disposed at the four corners are located close to the outer peripheral portion of the resin plate in a plurality of directions, and hence the hardening speed of plastic resin at these points is specifically high among the cylinders disposed at the outer peripheral portion of the resin plate. Therefore, occurrence of molding sinks on the end surfaces of the respective cylinders is uniformized by the roughened end surface

of the cylinders disposed at the four corners, and hence flatness of the surface to be adhered to the light transmissible plate is improved.

In the microplate according to the aforementioned third embodiment of the present invention, the aforementioned wells may be formed by adhering the aforementioned light transmissible plate to the end surfaces of the cylinders, which form the aforementioned through-holes, and the side surfaces of the aforementioned cylinders provided on the outer peripheral portion of the aforementioned resin plate may be formed to be rougher than the side surfaces of those provided at the center of the aforementioned resin plate.

Although the side surfaces of the cylinders are not surfaces to which the light transmissible plate is directly adhered, since the effect of uniformization of occurrence of molding sink may be obtained owing to these rough side surfaces, flatness of the surface to be adhered to the light transmissible plate is improved.

In this structure, it is also possible to arrange the aforementioned cylinders at regular intervals in the vertical and lateral directions into a square shape on the aforementioned resin plate, and the side surfaces of the cylinders disposed at the four corners of those

disposed into a square shape may be formed to have rougher surface than the side surfaces of others.

As described above, in the case in which the aforementioned cylinders are arranged as described above on the resin plate, the hardening speed of plastic resin at the portions where the cylinders at the four corners are disposed is specifically high among the cylinders disposed at the outer peripheral portion of the resin plate. Therefore, occurrence of molding sink at the positions where the respective cylinders are disposed may be equalized owing to the roughened side surfaces of the cylinders disposed at the four corners, and hence flatness of the surface to be adhered to the light transmissible plate is improved.

In the microplate according to the aforementioned third embodiment of the present invention, the aforementioned resin plate is formed by covering the metal plate with plastic resin by injecting and molding plastic resin from the one side of the metal plate, and hence the surface of the aforementioned resin plate to be adhered to the aforementioned light transmissible plate may be formed so that roughness thereof increases with increase in distance from the position of injection gate of plastic resin when the aforementioned resin plate is formed.

At the time of inj ection molding of the resin plate, since the temperature in the forming die is lowered with increase in distance from the position of injection gate of plastic resin, the hardening speed of plastic resin increases. Therefore, when the distance from the position of injection gate of plastic resin when the resin plate is formed increases, occurrence of molding sink is uniformized owing to the rough surface thereof, and hence flatness of the surface to be adhered to the light transmissible plate is improved.

A forming die used for forming resin plate as a component of a microplate having a plurality of wells for storing samples to be observed by injection molding of plastic resin, in which the wells are formed by adhering the light transmissible plate having alight transmitting property thereto so as to cover openings of through-holes provided on the resin plate formed by injection molding on one side, and the outer peripheral portion of a transfer surface for transferring a surface of the aforementioned resin plate to be adhered to the light transmissible plate is formed to be rougher than the center portion of the transfer surface is also included in the present invention, and the resin plate which is a component of the microplate according to the aforementioned first embodiment of the present invention may be formed by

performing injection molding of plastic resin using the forming die. In addition, a method of manufacturing a resin plate using this forming die also relates the present invention.

Also, a forming die used for forming resin plate as a component of a microplate having a plurality of wells for storing samples to be observed by injection molding of plastic resin, in which the aforementioned wells are formed by adhering a light transmissible plate having a light transmitting property thereto so as to cover openings of through-holes provided on the aforementioned resin plate formed by injection molding on one side, and the outer peripheral portion of a transfer surface for transferring a surface of the aforementioned resin plate to be adhered to the aforementioned light transmissible plate is formed to be rougher than the center portion of the transfer surface is also included in the present invention, and the resin plate which is a component of the microplate according to the aforementioned third embodiment of the present invention may be formed by performing injection molding of plastic resin using the forming die. In addition, a method of manufacturing a resin plate using this forming die also relates the present invention.

According to any modes of the present invention

described above, flatness of the surface of the plastic resinplate, whichis formed into amicroplate by adhering the light transmissible plate, to be adhered to the light transmissible plate is effectively improved.

Brief Description of Drawings Fig. 1 is a drawing showing a first example of a microplate according to the present invention.

Fig. 2 is a drawing showing a second example of the microplate according to the present invention.

Fig. 3 is a drawing showing an example of a resin plate used in a third example of the microplate according to the present invention.

Fig. 4 is a drawing showing an example of a structure of a forming die used for forming the resin plate used in the microplate according to the present invention.

Fig. 5 is an explanatory drawing showing a procedure of manufacturing of the resin plate.

Fig. 6 is a drawing showing an example of a structure of a microplate in the related art.

Fig. 7 is an explanatory drawing showing an example of usage of the microplate.

Best Mode for Carrying Out the Invention Referring to the drawings, embodiments of the

present invention will be described. Parts which are identical to those shown in Fig. 6 are represented by the identical reference numerals.

Fig. 1 will now be described. Fig. 1 shows a first example of a microplate according to the present invention. Fig. 1 is a cross-sectional view of a microplate 1 according to the present invention similar to that sown in Fig. 6 (d).

As is clear from both of Fig. l (a) and Fig. 1 (b), the microplate 1 is formed by adhering a cover glass 4 having light transmitting property on one side of a resin plate 3 with adhesive.

The resin plate 3 is formed of resin 5, which is plastic material such as polypropylene. In the resin plate 3, there is provided an aluminum plate 6 as a metal plate, and the aluminum plate 6 covered by resin 5 constitutes the resin plate 3. The aluminum plate 6 is formed with round holes of larger diameter than an inner diameter of a well 2 at intervals corresponding to the arrangement of the wells 2 so as to prevent the aluminum plate 6 from being exposed inside the well 2 and coming into direct contact with samples. In other words, the resin plate 3 is a plate shape member including the wells 2 connected with each other at the positions of the round holes provided on the aluminum plate 6. Since one side

of openings of the cylindrical wells 2 is covered by the cover glass 4, the samples stored in the well 2 may be retained.

The microplate 1 shown in Fig. 1 (a) is different from that shown in Fig. 6 (d) in that outer side surfaces (surfaces indicated by a reference sign A in the same drawing) of the wells 2 on the resin plate 3 are formed to be rougher than the surface of the resin plate 3 to be adhered to the glass plate 4.

The microplate 1 shown in Fig. 1 (b) is different from that shown in Fig. 6 (d) in that the end surfaces (surfaces shown by a reference sign Bin the same drawing) of the openings of the cylinders formed of resin 5, which constitute the wells 2 in the resin plate 3, on the side where the glass plate 4 is not adhered are formed to be rougher than the surface of the resin plate 3 to be adhered to the glass plate 4.

Though details are shown later, the resin plate 3 having such an aluminum plate 6 sandwiched therebetween is formed by disposing the aluminum plate 6 in a forming die, and injecting and molding resin 5 from one side of the aluminum plate 6 in the forming die. Here, in order to roughen the specific surface of the resin plate 3 as described above, a transfer surface of the forming die corresponding to this specific surface is formed

to have a rough surface.

When the transfer surface of the forming die is roughened, resin 5 cannot be filled into the valley portions of the transfer surface having concavities and convexities sufficiently at the time of filling resin 5 into the forming die. Consequently, friction generated between the transfer surface and resin 5 is lowered. Consequently, molding sink of resin 5 may easily occur on this surface. When expressing the fact that molding sink may easily occur at these points in other words, molding sink can hardly occur on the surface of the resin plate 3 to be adhered to the glass plate 4.

In the microplate 1 shown in Fig. 1 (a), the outer side surfaces of the wells 2 on the resin plate 3 are formed to be rougher than the surface of the resin plate 3 to be adhered to the glass plate 4. However, if it does not work specifically against observation of samples stored in the wells 2, it is also possible to form the microplate 1 using the resin plate 3 in which the inner surfaces of the wells 2 (inner surfaces of the cylinders) is formed to be rougher than the surface of the resin plate 3 to be adhered to the glass plate 4. In this structure as well, an effect such that molding sink may hardly be occurred on the surface of the resin plate

3 to be adhered to the glass plate 4 is achieved.

Fig. 2 will now be described. Fig. 2 shows a second example of the microplate according to the present invention. Fig. 2 also shows a cross section of the microplate 1 similar to Fig. 6 (d).

The microplate 1 shown in Fig. 2 has a structure similar to the first example of the aforementioned microplate according to the present invention, that is, a structure in which the wells 2 are formed by adhering the glass plate 4 on one side so as to cover the openings of the cylinders of resin 5 provided on the resin plate 3 formed by covering the aluminum plate 6 with resin 5. However, the surface of the resin plate is not roughened and is different in that the surface of the aluminum plate 6 on the side having openings which are covered by the glass plate 4, is formed to be rougher than the surface to which the glass plate 4 is adhered.

The resin plate 3 including the aluminum plate 6 sandwiched therein as described above is formed by disposing the aluminum plate 6 having one of the surfaces roughed as described above in the forming die, and injecting and molding resin 5 fromone side of the aluminum plate 6 into the forming die as in the aforementioned first example.

When the surface of the aluminum plate 6 is

roughened when resin 5 is filed in the forming die, resin 5 cannot be filled into the valley portions of the rough surface having concavities and convexities sufficiently.

Consequently, since friction generated between the rough surface and resin 5 is lowered, molding sink may easily occur. When expressing the fact that possibility of occurrence of molding sink of resin 5 is increased on the surface which comes into contact with the surface of the aluminum plate 6 having the openings to be covered by the glass plate 4 in other words, molding sink of the surface of the resin plate 3 on the side having the openings covered by the glass plate 4 can hardly occur.

While the surface of the aluminum plate 6 on the side having openings covered by the glass plate 4 is formed to be rougher than the other surface in the microplate 1 shown in Fig. 2, the microplate 1 may be formed using the resin plate 3 formed by covering the aluminum plate 6, having the same degree of roughness on both sides, with resin 5. Accordingly, since occurrence of molding sink of resin 5 on the contact surface with the surface of the aluminum plate 6 is equalized on both surfaces, warping of the resin plate 3 due to molding sink is alleviated.

Fig. 3 will now be described. Fig. 3 is an example of the resin plate 3 used in a third example of the

microplate according to the present invention, showing a bottom surface of the resin plate 3, which is the surface to be adhered to the glass plate 4. The resin plate 3 is provided with cylinders 10 formed of resin 5 and defining the side walls of the wells 2 arranged in four rows and four columns into a square. By adhering the glass plate 4 to the end surfaces of the cylinders 10 on the side shown in the drawing, sixteen wells 2 are formed on the microplate 1.

The resin plate 3 shown in Fig. 3 has a similar structure to that used in the first example or the second example of the microplate according to the present invention described above, that is, and a structure in which it is formed by covering the aluminum plate 6 with resin 5. The resin plate 3 is formed by disposing the aluminum plate 6 in the forming die as in the aforementioned first example, and injecting and molding resin 5 from one side of the aluminum plate 6 in the forming die.

The resin plate 3 shown in Fig. 3 (a) is characterized in that the end surfaces (shaded surface with diagonal lines in Fig. 3 (a) ) of the cylinders 10 disposed at the outer peripheral portion of the resin plate 3 out of those provided on the resin plate 3 are formed to be rougher than the end surfaces (the surface

which is not shaded in Fig. 3 (a) ) of those disposed at the center portion of the resin plate 3.

As described above, when the transfer surface of the forming die to be used for injection molding of the resin plate 3 is roughened in order to roughen the surface of the resin plate 3, molding sink tends to occur on resin 5 which comes into contact with the roughened portion of the transfer surface at the time of injection molding. Therefore, as shown in Fig. 3 (a), by roughening the end surfaces of the cylinders 10 provided on the outer peripheral portion on the surface of the resin plate 3 as shown in Fig. 3 (a), occurrence of molding sink at the outer peripheral portion of the resin plate, in which possibility of occurrence of molding sink is generally lower than the center portion, is promoted, and consequently, occurrence of molding sink is equalized on the resin plate 3 between the outer peripheral portion and the center portion.

In the example of Fig. 3 (a), although the end surfaces of the cylinders 10 disposed at the outer peripheral portion on the surface of the resin plate 3 to be adhered to the glass plate 4 are roughened, the end surfaces of the cylinders 10 disposed at the outer peripheral portion on the surface of the resin plate 3 opposite from the side to be adhere to the glass plate

4 may be formed to be rougher than the end surfaces of those disposed at other positions. Accordingly, occurrence of molding sink of resin 5 is equalized on both surfaces of the resin plate 3, and hence warping <BR> <BR> of the resinplate 3 caused by molding sink is alleviated.

In the example of Fig. 3 (a), although the end surfaces of the cylinders 10 disposed at the outer peripheral portion of the resin plate 3 are roughened, the side surface of the cylinders 10 disposed at the outer peripheral portion of the resin plate 3 may be roughened as in the structure of the cylinders 10 shown in Fig. 1 (a) in the first example of the aforementioned microplate according to the present invention instead.

In this structure, occurrence of molding sink is equalized between the outer peripheral portion and the center portion of the resin plate 3.

The resin plate 3 shown in Fig. 3 (b) will now be described. The resin plate 3 is the same as that shown in Fig. 3 (a) in that the end surfaces of the cylinders 10 disposed at the outer peripheral portion of the resin plate 3 (surface shaded with diagonal lines or dotted <BR> <BR> in Fig. 3 (b) ) out of those provided on the resin plate 3 are formed to be rougher than the end surfaces (the surface which is not shaded with diagonal lines nor dotted in Fig. 3 (b) ) of those disposed at the center portion

of the resin plate 3. In addition to it, the resin plate 3 shown in Fig. 3 (b) is characterized in that the end surfaces of the cylinders 10 which are disposed at four corners of those disposed into a square shape on the <BR> <BR> resin plate 3 (dotted surfaces in Fig. 3 (b) ) are rougher than the end surfaces of others disposed at the outer peripheral portion of the resin plate 3 (the end surfaces of the cylinders 10 shaded with diagonal lines in Fig.

3 (b)).

In the case where the cylinders 10 are disposed on the resin plate 3 as described above, since the cylinders 10 disposed at four corners are close to the outer peripheral portion of the resin plate 3 in a plurality of directions (two directions out of up, down, <BR> <BR> left, and right in Fig. 3 (b) ), the hardening speed of resin 5 at these points is specifically high among the cylinders 10 disposed at the outer peripheral portion of the resin plate 3. Therefore, by roughening the end surfaces of the cylinders 10 disposed at the four corners, occurrence of molding sink at the four corners of the resin plate 3, in which possibility of occurrence of molding sink is generally low, is promoted, and consequently, occurrence of molding sink on the entire surface of the resin plate 3 may be uniformized.

As regards the resin plate 3 shown in Fig. 3 (b),

as in the example shown in Fig. 3 (a), the end surface of the cylinder 10 disposed at four corners of the outer peripheral portion of the surface of the resin plate 3 opposite from the surface to be adhered to the glass plate 4 may be formed to be rougher than the end surfaces of those disposed at other positions on this specific surface. Accordingly, since occurrence of molding sink of resin 5 is uniformized on both surfaces of the resin plate 3, warping of the resin plate 3 caused by molding sink may be alleviated.

In the resin plate 3 shown in Fig. 3 (b), as in the example shown in Fig. 3 (a), the side surfaces of the cylinders 10 disposed at four corners of the outer peripheral portion of the resin plate 3 may be roughened.

In this structure as well, occurrence of molding sink on the entire surface of the resin plate 3 may be uniformized.

The resin plate 3 shown in Fig. 3 is formed by arranging the cylinders 10 in four rows and four columns into square. However, when forming the microplate 1 using the resin plate 3 including a larger number of cylinders 10 connected to each other, the end surfaces of the cylinders 10 on the side of the resin plate 3 to which the glass plate 4 are adhered may be formed to be rougher with increase in distance from the position

of injection gate of resin 5 when the resin plate 3 is formed by injection molding.

At the time of injection molding of the resin plate 3, since the temperature of resin 5 is decreased as it flows away from the position of injection gate inside the forming die, and hence the hardening speed of resin 5 increases correspondingly. Therefore, by forming the resin plate 3 in the manner described above, occurrence of molding sink is uniformized.

Subsequently, a method of manufacturing the resin plate, which is formed by injection molding of plastic resin, as a component of the aforementioned microplate will be described.

Referring to Fig. 4, there is shown an example of the structure of a forming die used when forming the resin plate, which is a component of the microplate according to the present invention, by injection molding of plastic resin.

In Fig. 4, (a) is a cross-sectional view of a stationary die 11 and a movable die 12. A passage for guiding resin 5 to a cavity is omitted in this cross-section. By using this forming die, the resin plate 3 including the cylinders 10 formed of resin 5 defining the side walls of the wells 2 as shown in Fig.

3, are disposed in four rows and four columns into a

square shape is formed.

In the forming die shown in Fig. 4 (a), the surface of the resin plate 3 on the side to be adhered to the glass plate 4 is formed by the transfer surface of the stationary die 11.

In order to roughen the specific surface of the resin plate 3 or part thereof in this case, the transfer surface of the forming die corresponding to the portion to be formed into a rough surface is formed into a rough surface. Therefore, when forming the resin plate 3 in which the outer side surfaces of the wells 2 on the side to be adhered to the glass plate 4 are roughened as shown in Fig. l (a) for example, the transfer surfaces of the stationary die 11 indicated by the reference sign A are roughened. Also, as shown in Fig. 1 (b) for example, when forming the resin plate 3 in which the end surfaces of the openings of the wells 2 on the side not to be adhered to the glass plate 4 are roughened, the transfer surfaces of the movable die 12 indicated by the reference sign B are roughened. Furthermore, as shown in Fig. 3 for example, when forming the resin plate 3 in which the end surfaces of the cylinders 10 to be disposed at the outer peripheral portion thereof are roughened, the transfer surfaces corresponding to the specific end surfaces in the forming die are roughened.

In Fig. 4, (b) shows a position of gate (injection port of resin 5 into the cavity) in the stationary die 11. As shown in the Fig. 4 (b), the gate is arranged at the center of the surface of the resin plate 3 to which the glass plate 4 is not adhered in the stationary die 11.

Subsequently, a procedure of forming the resin plate 3 using the forming die shown in Fig. 4 will be described based on Figs. 5 (a) to (f). In Fig. 5, the <BR> <BR> stationary die 11, the movable die 12, the aluminum plate 6, and the resin plate 3 are shown in a frame format.

First, in (a), the temperature of the stationary <BR> <BR> die 11 and the movable die 12 are adjusted to predetermined degrees respectively.

Then, as shown in (b), the stationary die 11 and the movable die 12 are separated, and the aluminum plate 6 is fitted into the movable die 12. When forming the resin plate 3 as a component of the microplate according to the second example of the present invention as described above, one of the surfaces of the aluminum plate 6 to be fitted into the movable die 12 is roughened.

Subsequently, as shown in (c), the movable die 12 in which the aluminum plate 6 is fitted is moved toward the stationary die 11 to close the forming die.

Then, as shown in (d), melted resin 5 is filled

into a cavity of the forming die from the side of the stationary die 11.

Subsequently, in (e), resin 5 is hardened while applying a predetermined pressure by the forming die.

Subsequently, after the resin 5 is cooled, the movable die 12 is retracted from the stationary die 11 to open the forming die as shown in (f), and the resin plate 3 is taken out. Subsequently, when a runner 13 is removed, the resin plate 3 is obtained.

The resin plate 3 is formed in the procedure as described above.

Subsequently, conditions of experimental manufacture when the resin plate was manufactured according to the aforementioned manufacturing method will be described.

The resin plate manufactured experimentally was such that the number of cylindrical wells was 384 (24 <BR> <BR> 16), andthepitchofthewellswas4. 5mm. Thealuminum plate used had a rectangular shape having dimensions of 119'77 mm in length, and 1. 0 mm in thickness, and was provided with round holes of 3.6 mm in diameter at the pitch of the well. Then, a resin plate being rectangular of 110 74 mm in outline of resin portion and 2.0 mm in thickness of resin (total thickness including the aluminum plate was 5.0 mm), and having

the wells of 2.2 mm in inner diameter was experimentally manufactured.

The total thickness of the resin plate here means the height of the cylinder defining the side wall of the well. Although the thickness of the well connecting portions is arbitrary, it is preferable to employs the thickness within the range of 0.5 to 1.0 mm. In this experimental manufacture, the thickness of the connecting portion was set to 0.7 mm.

Subsequently, various conditions at the time when the resin plate of the aforementioned shape and structure was manufactured will be described based on Figs. 5 (a) to (f).

In this experimentally manufacture, although the roughness of the rough surface provided on the transfer surfaces of the forming die was Rz=0.05 mm, the range of this value is preferably within the range of 0.005 <BR> <BR> to 0. 5 mm. The reference sign Rz designates a"ten-point height of irregularities".

The ten-point height of irregularities is obtained by sampling a roughness curve showing the roughness of the transfer surface by the length corresponding to the reference length in the direction of average line of the curve, determining the average value of the roughness curve of the sampled portion as a reference value, and

adding the average value of the absolute values of the heights of the apexes of projections from the highest one to the fifth one from the reference value to the average value of the absolute values of the depths of the bottoms of the recesses from the lowest one to the fifth lowest one from the reference value measured in the direction of the depth magnification.

In this experimental manufacture, the gates are provided at four points in the forming die, and the positions of the respective gates are positioned at the centers of the four rectangulars obtained by dividing the rectangular, which is the shape of the resin portion of the resin plate into halves in the vertical and lateral directions. The hole diameter of each gate is preferably within the range of 0.3 to 1. 0 mm in diameter in the resi plate of this size, and in the experimental manufacture, the hole diameter was set to 0.5 mm.

The set temperature of the stationary die 11 and the movable die 12 in Fig. 5 (a) is preferably in the range from 40 to 100°C, and in this experimental manufacture, the set temperature was set to 80°C.

In Fig. 5 (d), the experimental manufacture was performed using polypropylene as resin. Here the temperature of resin at the time filling resin is preferably in the range from 160 to 220°C, and in this

experimental manufacture, the temperature of resin was <BR> <BR> set to 190°C. The injection speed of resin is preferably in the range from 30 to 200 mm/sec, and the injection pressure is preferably within the. range of 300 to 2000 kgf/cm2, and in the experimental manufacture, they were set to 100 mm/sec and 700 kgf/cm2, respectively.

In Fig. 5 (e), the pressure to be given to resin when resin is being hardened (dwell pressure) is preferably within the range of 300 to 1000 kgf/cm2.

However, in the experimental manufacture, the dwell pressure was set to 600 kgf/cm2. The duration of application of dwell pressure is preferably within the range of 3 to 10 seconds, and in the experimental manufacture, the duration of application of the dwell pressure was set to 5 seconds.

The duration of cooling to be performed thereafter until the resin plate is taken out is preferably in the range from 5 to 20 seconds as shown in Fig. 5 (f), and in this experimental manufacture, it was set to 10 seconds.

As a result of performing experimental manufacture under the conditions described above, a desired resin plate could be formed.

The present invention is not limited to the aforementioned embodiments, and various improvements and modifications are possible without departing from the scope of the invention.