.
1. Transmissive Collimator
.
1.1 Definition and Working Principle
.
A transmissive collimator is a precision optical instrument designed to convert divergent light from a source into a collimated (parallel) beam via a transmissive optical system.
Its core operating principle: A transmissive reticle is precisely positioned at the focal plane of the collimating objective lens. As light passes through the objective, it emerges as an ideal parallel beam—functionally equivalent to simulating an object located at infinity.
.
1.2 Core Configuration
.
- Light source
- Condenser lens
- Transmissive reticle (resolution target, star test target, crosshair reticle)
- Collimating objective lens
.
1.3 Key Applications
.
（1）Characterizing optical performance:
.
- Measuring the focal length, relative aperture, resolution, distortion, and chromatic aberration of lenses and imaging systems (e.g., camera lenses, microscope objectives, telescopic objectives)
.
（2）Optical axis calibration:
.
- Aligning the optical axis parallelism of telescopes, aiming sights, and precision optical instruments; verifying and correcting collimation errors in optical assemblies.
.
（3）Dimensional metrology:
.
- Determining the apex angle, wedge angle, and parallelism of prisms, optical flats, and transparent components; serving as a reference for high-precision small-angle measurements.
.
（4）Academic & research use:
.
- Acting as a standard optical benchmark for validating geometric optics principles and constructing collimation-based experimental setups.
.
.
2. Optical Bench
.
2.1 Definition and Core Functions
.
An optical bench is a precision mechanical platform integrated with linear guide rails, graduated scales, and adjustable mounts. It fulfills three critical roles:
- Securing optical components (lenses, prisms, filters, collimators, screens, etc.);
- Ensuring the optical path is coaxial and height-aligned (critical for minimizing system errors);
- Enabling accurate quantification of positional relationships (e.g., component spacing, image formation distances) via precise linear displacement measurements.
.
2.2 Core Configuration
.
- Precision linear guide rail
- High-resolution graduated scale
- Adjustable mounts (height/tilt/rotation)
- Sliding stages
.
2.3 Key Applications
.
（1）Fundamental optical parameter measurement:
.
- Quantifying the focal length, refractive index, magnification, and imaging characteristics of thin/thick lenses (positive/negative); studying object-image relationships.
.
（2）Spectroscopic & dispersive experiments:
.
- Performing tests on light dispersion, spectral analysis, and grating diffraction; measuring critical parameters such as minimum deviation angle and grating constant.
.
（3）Optical system integration:
.
- Constructing custom setups (e.g., Keplerian/Galilean telescopes, compound microscopes, projection systems) for educational or industrial use.
.
（4）High-precision testing (in tandem with collimators):
.
- Providing stable, repeatable mechanical support for collimator-based measurements (the gold standard for industrial and laboratory testing).
.
.
3. Combined Applications of Transmissive Collimators and Optical Benches
.
The pairing of these two instruments constitutes a standard configuration for optical metrology and system alignment, enabling:
- Precision calibration of lens focal length (typical accuracy: ±0.1% or better);
- Optical resolution testing using standardized resolution targets (quantifying maximum resolvable line pairs);
- Alignment and validation of telescopic/microscopic systems (optimizing objective-eyepiece-reticle positioning and optical axis collimation);
- High-accuracy inspection of prisms, optical flats, and lenses (measuring parallelism, angular deviations, and transmission uniformity);
- Standardized experimental platforms for university-level optics education and advanced research.
.
.
4. Operating Precautions
.
- Prioritize coaxiality and height alignment of all optical components to minimize systematic errors.
- Ensure the collimator’s reticle is strictly positioned at the collimating objective’s focal plane (critical for generating true parallel light).
- Conduct multiple replicate measurements and adopt the average value to enhance data reliability.
- Handle sliding stages and guide rails with care to avoid damage; maintain optical surfaces free of contamination (dust, fingerprints) to preserve measurement accuracy.
Item | Transmissive Collimator | Optical Bench |
| Principle / Core Function | The reticle is placed at the focal plane of the collimating objective, emitting parallel light to simulate an infinite target and provide an optical testing benchmark. | A precision guide-rail platform for fixing, coaxial adjustment, precise positioning and measurement of optical components. |
| Core Structure | Light source, condenser lens, transmissive reticle (resolution / star / crosshair), collimating objective lens. | Precision guide rail, scale ruler, adjustable mounts (height / tilt / rotation), sliding bases. |
| Main Applications | 1. Lens focal length, resolution, image quality testing; 2. Optical axis calibration; 3. Angle / parallelism measurement of prisms / flats; 4. Experimental benchmark. | 1. Measurement of lens focal length, refractive index; 2. Optical experiments (dispersion, grating); 3. Construction of telescopic / microscopic systems; 4. High-precision testing with collimator. |
| Key Operating Points | 1. Reticle strictly aligned with focal plane; 2. Coaxial with tested components; 3. Avoid reticle contamination. | 1. Ensure coaxial and equal-height light path; 2. Move slides gently to protect rails; 3. Average multiple readings. |
| Combined Core Applications | Lens focal length calibration, resolution testing, optical system alignment, component parameter measurement, teaching experiment platform. |
