Manual Stages & Others

Classification, mechanism, guiding methods

■Classification, mechanism, guiding methods
  1. Dovetail groove (D-T method)
  2. V-groove rail and steel balls (V-B method)
  3. V-groove and cross roller (V-CR method)
  4. V-groove and cross roller (HG-VCR method)
■Driving mechanism of oblique stage
  1. Outline of combination coupling mechanism
  2. Traditional techniques and problems
  3. Features of combination coupling mechanism
  4. Positioning errors
  5. Patents

Dovetail groove (D-T method)

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■Structure
It has the sliding contact with an application of the dovetail groove mechanism that has a trapezoidal male dovetail and a female dovetail grooves, rather than having a rolling contact.

■Features
The guiding section has the sliding contact; so by the combination of male and female dovetail grooves, it is assembled as it slide smoothly.
Our stages mainly use the rack and pinion method for the driving mechanism. It has a longer stroke when compared to other stages, and it is low cost.

■Applications
This is used as the simple positioning stage rather than the stage used or precise adjustment. It is great for low-power microscopes, focusing unit for observing TV cameras, and positioning of the sample.

V-groove rail and steel balls (V-B method)

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■Structure
It has the guiding method that has steel balls between two V groove rails facing toward each other, for guiding with rolling balls between V grove rails.

■Features
The V groove rails have high parallelism and high flatness due to high precise cutting process after quench hardening.
The transfer precision is same as V-CR, and the withstand load is better than N-B and a bit worse than V-CR.

■Applications
This is used for the precision positioning stage for high precision and middle level load. It is good for precise feeding in optical experiments and fine adjustment positioning.

V-groove and cross roller (V-CR method)

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■Structure
It has the guiding method that has rollers alternately set between two V groove rails facing toward each other, for guiding with the roller between V groove rails.

■Features
V groove rails have high parallelism and high flatness due to high precise cutting process conducted after quench hardening. The rollers have special finishing that is almost same as a mirror, and with perfect diameter and uniformity, it provides very precise guiding. As the V groove and the rollers contact in a line structurally, the high precision transfer and a heavy withstand load are available.

■Applications
This is used for the precision positioning stage for high precision and heavy withstand load. It is good for precise feeding in optical experiments and fine adjustment positioning.
It is good for precise positioning and measurement for production machines and inspection machines. It can be used for length measurements such as precise quantitative feeding and measurement of transfer amount.

V-groove and cross roller (HG-VCR method)

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■Structure
It is a guide rail that has two of pair V groove rails (total of four rails for one set). These rails are made of steel quenching materials with V groove cutting process, and two rails were arranged as V grooves face toward each other. Inside of V grooves, rollers were located alternately in 90 degree.
This guide rail is at the highest level in rigidity as well as precision.

■Features
We took in the customers’ requests of smaller stages and higher rigidity, and developed a totally new guide rail for aiming to improve the cross roller guide performance. It enlarged the roller diameter to the maximum limit in the rail height, made the space between rollers as small as possible in order to increase a number of arrays to the maximum. There arrays are held by the retainer. High pre-compression can be applied, and it is compact and super high rigid.

■Applications
It is used for our new automatic and manual stages. It is good for precise positioning for sensors and cameras, precise positioning for production machines and inspection machines, measurements, and also various applications that have offset load.
　
　

Driving mechanism of oblique stage

To the oblique stages that are widely used in fields, where angle adjustments are required, such as optical pickup adjustment units and disc manufacturing systems, we have applied new driving mechanism and prepared a new lineup.
This driving mechanism is our “combination coupling mechanism CCM” we developed lately. It solved problems that the traditional oblique stages had, and achieved high precision, resolution, durability, and driving torque improvements.

Outline of combination coupling mechanism

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This “combination coupling mechanism” is applying the feed screw system instead of the worm gear system traditionally used for the driving mechanism of the oblique stages.
By coupling this feed screw and the tilting part to a device that switches over between translatory and angular movement, this mechanism is able to pass on the straight line trajectory of the feed screw to a circular trajectory of the tilting part.
This mechanism takes advantage of the preciseness of using screws, resulting in high resolution, smooth motion, and superior durability.

Issues with Conventional Technology

■Worm gear method
It is a common driving mechanism with the worm wheel and the worm gear. In this arrangement, part of the tilt stage upper table is made into part of a worm-wheel which is then driven by a worm gear. This mechanism had problems such as a heavy worm gear during performance and uneven torque due to worm gear eccentricity when a constant amount backlash or enough wrapping adjustment was not applied. In addition, the small area of contact between the worm gear and wheel can lead to problems with abrasion resistance.

■Actuator + spring method
This is a mechanism used for general microscope stages that works by using an actuator and spring. This backlash-free mechanism uses an actuator that pushes on the upper table and a spring that tries to return it back in the direction of the actuator. There are several identified problems when using this mechanism. For example, the load on the actuator becomes quite high if a very powerful spring is used, the table can become unresponsive if it experiences a high load when being driven, or the table may not return to its original position if the spring force is to weak.
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Features of the Complex Coupling Mechanism

The complex coupling mechanism is driven by a feed screw and a specially designed coupling part. When compared with conventional technology, this design has the following features:

• High resolution when compared to worm gear method
• A specially designed coupling part allows free movement which absorbs any rotation irregularities.
• The small drive torque enables smooth movement.
• Durability is improved due to having a larger contact surface area than worm gears.
• Reliable movement control is possible due to the spring-free design.
• By changing the feed screw lead, the resolution and movement speed can be varied.
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Positioning errors

When the straight line motion is converted into angular motion, there are angular positioning errors along the tangent curve between the amount of feed screw movement and the tilting part that actually moves, as well as along the sine curve of the distance between the feed screw and the tilting part. However in reality, microscopic positioning errors are within ±3° of the amount of movement which is much less that the ±5° you get with worm gear positioning. It is also possible to achieve high positioning precision by performing error compensation.
※Errors are the ones occurred when the angle of 0.573°
is set as a standard in 1-mm feeding with the feed screw
The above values were given from the following formula
　　　Positioning error in a distance between the feed screw and the oblique section (“n” presents the transfer amount of the feed screw)
　　　　　Positioning error = sin・ (1 mm/100 mm) x n-sine・ (1 n/100 mm)
　　　Positioning error between the transfer amount and the actually moving oblique section (“n” represents the transfer amount of the feed screw)
　　　　　Positioning error = tan・ (1.1 mm/100 mm) x n-tan・ (1 n/100 mm)
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Patents

The “Complex Coupling Mechanism” has been registered under patent number 3848304 as a “Table position adjuster”.

■Stages that combination coupling mechanism is applied.
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