WD640 Projector Lens 0.38:1 for 4 Eiki Projectors CL6600U RL-M7U RL-M8U RL-M9U

The WD640 is a short-throw lens designed for 0.64-inch panels (Roly), with a throw ratio of 0.38:1. It is compatible with 4 projector models across 1 model series. This article lays out the lens specifications, installation distances, model compatibility list, and replacement key points all at once.

1. Lens Specifications

2. Converting Throw Ratio to Installation Distance

The throw ratio is the ratio of installation distance to screen width. This lens is fixed-focus (0.38:1), so the installation distance changes linearly with screen size and there is no adjustment margin—measure accurately before installation.

The above figures are the clear distance from the lens face to the screen, excluding rear ventilation and cabling space behind the projector body. Calculated for 16:10 aspect ratio; actual values are subject to on-site measurement and the instruction manual.

3. Compatible Models (4 Projectors, Roly)

The table below is arranged from newest to oldest by production start date, including each model's resolution, brightness, and original standard lens zoom ratio, making it easy to quickly match project requirements.

The zoom ratio refers to the zoom factor of the model's original standard lens (upper limit ÷ lower limit of the original throw ratio range), not the zoom range of the lens described in this article.

Common Features of These Models

The original standard lens throw ratios of these 4 models are mostly concentrated in the 1.10~1.88 range. The 0.38:1 model in this article represents an adjustment in focal range—the same projection distance can produce a different screen size, which is precisely the direct reason for swapping lenses; at the same time, full shift capability is retained, so the image can still be aligned after adjusting the focal range.

4. Three Things to Confirm Before Replacement

• Panel and resolution must match. This model is designed for 0.64-inch panels. Machines with different panel sizes or resolutions will show some differences in projection performance; it is safest to verify against the unit's nameplate before installation.
• Interface and locking structure. Interface compatibility is generally good within the same platform generation, but locking latch positions differ between generations. If the image is skewed or edges are soft after installation, it is usually because the lock is not fully engaged—not a problem with the lens itself.
• Fixed focus means no zoom margin. Screen size can only be changed by moving the projector body, so venue dimensions must be measured accurately in advance, with an additional 10–20 cm allowance at each end.

For models not on the list, it is more reliable to send us the unit nameplate and a photo of the original lens for verification—same-generation platforms often share interfaces, but ordering based on model similarity alone is not worth the risk.