- Reflectivity
HR-94
For scanner, photocopy machine, rear projection TV, OHP and so on.
HR-97-#, HR-98-#
For photocopy machine, rear projection TV, liquid crystal projector and so on.
HR-78-A, HR-78-B
For LBP (Laser Beam Printer) or other OA digital products.


Flowchart and reinforcement method
Type: Lead glass, soda glass, borax glass, BK7, BK263 and so on, totaling 100-odd types. Their natural transmission rate and reflectivity are different from each other. T% is about 84% ~ 92%, and R% 0.2% ~ 1.6%.

Flowchart
Raw materials——Boiler——Forming ——Cooling down——Cleaning——Classification


Reinforcement method

· Physical reinforcement
· Chemical reinforcement

1.Physical reinforcement
The glass is heated to its softening point and then quickly cooled down in the cooling liquid to destroy its original molecular structure. After that, a new structure will form with higher density and the glass is reinforced with increased compact resistance. Its advantage lies in quick reinforcement and large output, but the glass tends to deform and that will affect the flatness and bring difficulties to the classification of strength. Therefore, physical reinforcement is usually employed in building materials, furniture, industrial facilities and vehicles, and not so suitable for photoelectronic products that need higher flatness.


2.Chemical reinforcement
The glass is immersed in a special chemical solution, whose concentration, pH and temperature are all within a specified range. After a period of time, a hard film will form on the surface of glass and in this way the glass is reinforced.

The conditions for chemical reinforcement are as follows:
1）The concentration should be controlled.
2）The temperature should be 300°C to 400°C.
3）The value of pH should be controlled.
4）The reinforcement time should be nicely controlled.
5）The hardness of glass should be known in advance.
The above conditions should be adequately controlled, otherwise the strength of glass will be affected after reinforcement.

In general, the reinforcement time is an important factor that will affect the strength directly. According to the properties of product and customer’s requirements, the reinforcement time should be classified. Normally, it needs 16 hours and the resulting strength is about three times that after physical reinforcement. In some special case, the reinforcement time can be as long as 24 hours. Besides, customer’s requirement on compact resistance should also be considered. For the standard reinforcement (16 hours), the glass should be OK if it is not destroyed by a lead ball of 500g that drops freely from a height of 0.7m.

The disadvantage of chemical reinforcement lies in long time, small output and high technology, but it has the advantage of low deformation and high flatness. Chemical reinforcement is suitable for large-area glass with a thickness under 3mm, especially for photoelectronic product, medical equipment, national defense industry and aerospace industry.
 

Purpose:
This document defines surface quality on optical components per MIL-O-13830.

Definitions:

• SCRATCH: Any marking or tearing of the part surface.
• DIG: A small rough spot on the part surface similar to a pit in appearance. A bubble is considered a dig.
• SLEEK SCRATCH: A hairline scratch.
   
• CRUSH or RUB SCRATCH: A surface scratch or a series of small scratches.

Method:
The size of a defect is to be measured through the use of an optical comparator:
Surface quality is to be specified by a number such as 60/40. The first digits relate to the maximum width allowance of a scratch as measured in microns. The next digits indicate to maximum diameter allowance for a dig in hundredths of a millimeter. Thus, as can be seen from the table below, a surface quality callout of 60/40 would permit a scratch width of .06 mm (60 micron -or- 0.0024") and a dig diameter of .40 mm (400 micron -or- 0.0158").