JPS5772821A - Forming method for pentagonal roof prism - Google Patents

Forming method for pentagonal roof prism

Info

Publication number
JPS5772821A
JPS5772821A JP14857980A JP14857980A JPS5772821A JP S5772821 A JPS5772821 A JP S5772821A JP 14857980 A JP14857980 A JP 14857980A JP 14857980 A JP14857980 A JP 14857980A JP S5772821 A JPS5772821 A JP S5772821A
Authority
JP
Japan
Prior art keywords
shape
prism
blank
angle
edge line
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP14857980A
Other languages
Japanese (ja)
Inventor
Masamichi Miyazaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP14857980A priority Critical patent/JPS5772821A/en
Publication of JPS5772821A publication Critical patent/JPS5772821A/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms

Landscapes

  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Mechanical Engineering (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Viewfinders (AREA)

Abstract

PURPOSE:To obtain a pentagonal roof prism which is high with respect to surfaces flatness, precision of mirror finish, accuracy of the angle and shape of edge line parts and the like, by a method wherein a blank prism molded in a shape as approximate as possible to the desired shape is placed in a finishing mold, and the surface layer parts of the blank prism are melted by heating and are formed to the desired shape. CONSTITUTION:The blank prism 11 having a shape approximate to the desired final shape is molded by ordinary injection molding. The blank prism 11 is placed in a cavity 15 of the finishing mold 14 and is applied with heat and pressure. The inside surfaces of the cavity 15 are mirror finished, and the edge line parts are accurate in angle and shape. The heating in the finishing mold 14 is performed at such an extent that the surface layer parts of the blank prism 11 are softened to a depth of about 0.1-0.2mm., followed by compressing and cooling. Accordingly, a pentagonal roof prims 1 which is high in flatness and surfaces smoothness, the accuracy of angle and shape of edge line parts and the like is obtained.
JP14857980A 1980-10-23 1980-10-23 Forming method for pentagonal roof prism Pending JPS5772821A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14857980A JPS5772821A (en) 1980-10-23 1980-10-23 Forming method for pentagonal roof prism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14857980A JPS5772821A (en) 1980-10-23 1980-10-23 Forming method for pentagonal roof prism

Publications (1)

Publication Number Publication Date
JPS5772821A true JPS5772821A (en) 1982-05-07

Family

ID=15455891

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14857980A Pending JPS5772821A (en) 1980-10-23 1980-10-23 Forming method for pentagonal roof prism

Country Status (1)

Country Link
JP (1) JPS5772821A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04163119A (en) * 1990-10-26 1992-06-08 Ricoh Co Ltd Manufacture of plastic molded item

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04163119A (en) * 1990-10-26 1992-06-08 Ricoh Co Ltd Manufacture of plastic molded item

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