Prism, prism production method, mold, and sensor chip

1. A prism which is constituted by a dielectric medium and is used for an analysis utilizing surface plasmon, comprising:

an incidence surface through which excitation light enters from an outside;

a reflection surface on which the excitation light which has entered through the incidence surface is reflected;

an emission surface through which the excitation light which has been reflected on the reflection surface exits; and

an opposing surface which is opposed to the reflection surface,

wherein a metal film is formed on the reflection surface,

wherein the opposing surface comprises a sink-mark surface,

wherein the sink-mark surface is transparent,

wherein a surface roughness Ra of the sink-mark surface is from 0.1 nm to less than 0.5 μm, and

wherein the sink-mark surface comprises a curved surface which forms a convexity towards the reflection surface.

2. The prism according to claim 1 ,

wherein the sink-mark surface is disposed vertically right below an area including an antigen trapping position of the metal film.

3. A method for producing the prism according to claim 1 , comprising:

preparing a mold with a certain cavity;

injecting a certain resin to fill the cavity;

applying a dwell pressure to the resin; and

cooling the resin,

wherein the mold comprises a transfer area for forming the sink-mark surface, and

wherein a surface roughness Ra of the transfer area is from 0.1 nm to less than 0.5 μm.

4. A method for producing the prism according to claim 1 , comprising:

preparing a mold with a certain cavity;

injecting a certain resin to fill the cavity;

applying a dwell pressure to the resin; and

cooling the resin,

wherein the opposing surface of the mold comprises a first transfer area for forming the sink-mark surface and a second transfer area for forming a non-sink-mark surface between the sink-mark surface and the incidence surface or the emission surface,

wherein a surface roughness Ra of the first transfer area is from 0.1 nm to less than 0.5 μm, and

wherein a surface roughness Ra of the second transfer area is from 0.5 μm to less than 100 μm.

5. A mold for producing the prism according to claim 1 , comprising:

a transfer area for forming the sink-mark surface,

wherein a surface roughness Ra of the transfer area is from 0.1 nm to less than 0.5 μm.

6. A mold for producing the prism according to claim 1 , comprising:

a first transfer area for forming the sink-mark surface of the opposing surface and a second transfer area for forming a non-sink-mark surface of the opposing surface between the sink-mark surface and the incidence surface or the emission surface,

wherein a surface roughness Ra of the first transfer area is from 0.1 nm to less than 0.5 μm, and

wherein a surface roughness Ra of the second transfer area is from 0.5 μm to less than 100 μm.

7. A sensor chip, comprising:

the prism according to claim 1 ; and

a channel forming body in which a channel is formed.

8. The prism according to claim 1 , wherein the metal film is made of Gold.

9. The prism according to claim 8 , wherein the Gold film has a film thickness of from 40 nm to 50 nm.

10. The prism according to claim 9 , wherein the prism is made of a resin material comprising a cycloolefin polymer.

11. The prism according to claim 10 , wherein water absorption of the prism is equal to or less than 0.2%.

12. The prism according to claim 11 , wherein the resin material of the prism has a photoelastic coefficient equal to or less than 80×10 −12 Pa −1 .