An Experimental Study on the Effect of Holding and Compression Pressures on The Birefringence Distribrtion in Injection-Modeled Disks

보압 및 압축이 원반형 사출품내의 복굴절 분포에 미치는 영향에 관한 실험적 연구

  • Published : 2000.05.01


Recently, injection molding process became more popular than ever to produce large quantities of high precision products or optical products. Especially, optical disk that was made by injection mol ding process has been used for many years as a music play media or computer sub-device. The density of data in disk media has been increased continuously. But those optical disks can cause sensorial problems because of high birefringence or deformation from the residual stresses in the media. Therefore, it is necessary to study the effects of various process conditions on the final bireffingence structure in injection-molded disks for producing precision injection-molded products. In the present paper we have focussed on the effect of holding and compression pressures on the optical anisotropy remaining in the MOD by examining the gapwise distribution of birefringence and extinction angle. The effect of holding pressure was found to form the inner two bireffingence peaks. But the effect of compression pressure on the bireffingence distribution was found to make the uniform distribution near the center in the gapwise direction. Finally, the value of the birefringence near the wall decreased as the mold temperature increased.


Injection Modeling;Birefringence;Optical Disk


  1. Aggarwala, B. D. and Saibel, E. 1961. 'Tempering Stresses in an Infinite Glass Plate,' Phys. Chem. Glasses., Vol. 2, PP. 137-140
  2. Wust, Jr C. J. and Bogue, D. C. 1983. 'Stress Optical Behavior in Polystyrene; Residual Stresses and Birefringence in Large, Quenched Samples' J. of Applied Polymer Science. Vol. 28, PP. 1931-1947
  3. Lee, E., Rogers, T., and Woo, T., 1965. 'Residual Stresses in a Glass Plate Cooled Symmetrically from Both Surfaces,' J. of the American Ceramic Society., Vol. 48, PP. 480
  4. Kamal, M. R. and Tan, V, 1978, 'Orientation in injection Molded Polystyrene,' S.P.E. Technical Papers. Vol. 24, PP. 121-126
  5. White, J. L., Dietz. W. and Clark, E. S. 1978. 'Theoretical and Experimental Studies of Orientation Distributions in injection Molded Parts of Glassy Plastics,' S.P.E. Technical Papers. Vol. 24, PP. 118-120
  6. Janeschiz-Kriegl, H. 1983, Polymer Melt Rheology and Flow Birefringence, Berlin, Springer Verlag
  7. Yoon, K. and Wang, K. K. 1991. 'Birefringence Measurements of Injection-Molded Disks,' S.P.E. Technical Papers. Vol. 37, PP. 333-337
  8. Yoon, K. 1995, 'An Experimental Study on Precision Injection Molding of Center-gated Disks,' The Korean J. of Rheology, Vol. 7, No. 1, pp. 19-27
  9. Isayev, A. I., 1987, 'Injection and Compression Molding Fundamentals,' New York and Basel. Marcel Dekker. INC.
  10. Menges, G. and Wubken, G., 1973, 'Influence of processing Conditions on Molecular Orientation in injection Moldings,' S.P.E. Technical Papers. Vol. 19, PP. 519-522
  11. Greener, J., Kesei. R. and Contestable B. A., 1989, 'The Birefringence Problem in Optical Disk Substrates: A Modeling Approach,' AIChE journal., Vol. 35, No. 3, PP. 449-458