How Dot-Matrix Displays Show Digits, Letters, and Pixel Graphics

Before you decide, check this first

Start from what the user has to be able to read, then check whether your circuit and mechanics can support it. Confirm against the actual characters, viewing distance, ambient light, driver and available space, not just how the part looks.

Dot-matrix LED display examples for digits, letters and pixel graphics
Figure: OPTO PLUS LED logo and English name shown on the standard dot matrix part 3Φ LED THT 5×7 Square Dot Matrix Display | 1.2″ Matrix Height (OPD-M35760(1)LA)

Figure: OPTO PLUS LED logo and English name shown on the standard dot matrix part 3Φ LED THT 5×7 Square Dot Matrix Display | 1.2″ Matrix Height (OPD-M35760(1)LA)

        Elevators, carriages, or advertising moving sign in everyday life use monochrome or multi-color dot matrix displays to display floor information, station current locations, and advertising information are very common applications, but dot matrix displays do not have the means to display all the details of each word and graphic, so must be rendered through simplified pixelated graphics, Arabic numerals, case English and Chinese Traditional. There are three most common types of display information for dot matrix displays:

  • Pixelated graphics
  • Arabic numerals / upper- and lower-case English
  • Traditional Chinese

        This article covers all three, using the square 3Φ 5×7 dot matrix display OPD-M35760(1)LA to build worked examples of Arabic numerals, upper- and lower-case English, and Traditional Chinese.

Use dot matrix display to display pixelated graphics.

There are usually two ways to use a dot matrix display to display pixelated graphics

Pixelate a high-resolution graphic, then show it on a dot matrix display

We use the Pixel Art network tool to express high-resolution graphics, pixilation will lose the characteristics of detail, the following image of OPTO PLUS LOGO for example, you can see that if you use more dots of dot matrix display, you can restore more details, if the product application needs to display very detailed patterns, you must choose a more dots , small pitch dot matrix display for a more complete performance.

Dot-matrix LED display structure and pixel arrangement
Figure: using the Pixel Art with two scale values (pixel size) 0.15 and 0.05 to pixelate the OPTO PLUS LED logo

Decide how many dots are needed, then draw the graphic

This is to determine how many dots to use, above the dot matrix, sketch out the pattern you want to represent, and then use a dot matrix display with enough dot to display, you can use an APP like piskel or an APP like dotpict to create the desired graph, and then use an LED dot matrix display with enough dots to display.  The following icon uses 32 x 32 dot matrix display to draw OPTO PLUS LOGO with dotpict, and the following image (A) is the final graphic. The dot matrix in practice, because the structure must be separated between each emitting dot, actually represents the dot spacing between the upper dot and the dot (Pixel pitch, also known as Dot pitch) must affect the graph, if use the square dot LED dot matrix display to show the above-mentioned OPTO PLUS LOGO, the appearance will look like Figure (B).

Dot-matrix LED display character layout example
The image by using 32×32 dot matrix to hand draw the OPTO PLUS LOGO(link) The image by using 32×32 square dot LED dot matrix display to perform OPTO PLUS LOGO.

Use the dot matrix display to display information

Besides pixelated graphics, the other job a dot matrix display does is show letters and Arabic numerals, and you can find those applications all around you. Take the ARIGATO spelled out at the 2020 Tokyo Olympics closing ceremony: square dot matrix displays render capital letters in a 5×7 format. Below we use the OPTO PLUS LED standard dot matrix part 3Φ 5×7 Square Dot Matrix Display (OPD-M35760(1)LA) as the basis for the most common content: capital letters, lower-case letters and Arabic numerals.

TOKYO 2020 Closing ceremony Twitter Post Form Olympic Twitter account

Use dot matrix display to display Upper case English Letters and Lower case English Letters

The format most commonly used to display English letters is the use of a 5×7 dot matrix font type, refer to the example of the font size available with 5×7 dot matrix font , provide on the network, the following illustration produces a 5×7 dot matrix diagram of OPTO PLUS. The following image produced a dot matrix to display OPTO PLUS by 5×7 dot matrix. Other commonly used formats are 5×9, 7×5, 3×5, 4×6.

Pixel grid used to form dot-matrix LED graphics
Figure: using a 5×7 OPD-M35760(1)LA  to spell out the OPTO PLUS LED English name “OPTO PLUS”

Use 5×7 dot matrix display to display upper case English Letters

The figure below uses the OPTO PLUS LED 3Φ 5×7 Square Dot Matrix Display (OPD-M35760(1)LA) to show every capital letter. Besides the figure below, you can also download the PDF version/PNG version

5 by 7 dot-matrix uppercase English alphabet patterns
Figure: using OPD-M35760(1)LA  showing capital letters A-Z (PDF)

Use 5×7 dot matrix display to display lower case English Letters.

The figure below uses the OPTO PLUS LED 3Φ 5×7 Square Dot Matrix Display (OPD-M35760(1)LA)  to show every lower-case letter. Besides the figure below, you can also download the PDF version/PNG version

5 by 7 dot-matrix lowercase English alphabet patterns
Figure: using OPD-M35760(1)LA  showing lower-case letters a-z (PDF)

Use 5×7 dot matrix display to display Arabic numerals.

The figure below uses the OPTO PLUS LED 3Φ 5×7 Square Dot Matrix Display (OPD-M35760(1)LA)  to show every Arabic numeral. Besides the figure below, you can also download the PDF version/PNG version

5 by 7 dot-matrix Arabic numeral patterns
Figure: using OPD-M35760(1)LA  showing Arabic numerals 0-9 (PDF)

Use dot matrix display to display Traditional Chinese

Referring to the《Speaking time:Chinese dot matrix》written by justfont , in this article, we can see that the minimum dot matrix that can display most of Chinese words is 16×16 dots, in addition to 24×24, 32×32,64×64, 128×128, and so on. With more dots, you can display more complete Chinese word details, the figure above with 16×16 dot matrix display to show「展躍」, two words.  The figure below with 16×16 square dot matrix hand-drawn Chinese .You can use the comparison of the figure above and the figure below to understand the detail difference shown in the dot matrix.

Dot-matrix pixel patterns for symbols and graphics
Figure: The two Chinese characters 展躍 hand-drawn on a 16×16 dot matrix grid.

In addition, justfont ‘s《Speaking time:Chinese dot matrix》also has a graphic for comparison, with 16×16/24×24/36×36 to show the same type of text details differences, if you need to display Chinese on the dot matrix display, you can refer to Bitmap font,or free dot matrix font making tool Bitmap Font Generator

Dot-matrix LED display pixel mapping example
Figure: Use three different dot matrixes (16×16, 24×24, 36×36) to display the Kai (regular script), Song (Ming) and Fangsong (imitation Song) typefaces (originally transferred from  justfont ‘sStory Time: Chinese Bitmap Fonts (justfont, in Chinese) )

Conclusion

A dot matrix display costs far less than an LCD screen, which is why it keeps showing up in applications with a tight budget that still need to show simple information. This article showed how to use a dot matrix display for pixelated graphics, capital letters, lower-case letters and Arabic numerals, so a product designer can pick the approach that fits the requirement. If you need standard dot matrix parts, or want to combine a dot matrix with other kinds of LED display, use our contact form, or email sales@opledtw.com, and OPTO PLUS LED will help you specify the right LED display for your product and your application.

FAQ

What information can a dot matrix display show?

A dot matrix display can show several kinds of simplified, pixelated information:
Pixelated graphics
Arabic numerals and English letters
Traditional Chinese

How does a dot matrix display show pixelated graphics?

There are two ways:

Pixelate a high-resolution graphic: process the graphic down to pixels, then render it on the dot matrix. The more dots you use, the more detail survives.
Hand-draw at a fixed dot count: decide the dot count first, sketch the pattern on the dot matrix grid, then use a display with enough dots to show it.

How does a dot matrix display show letters and Arabic numerals?

A dot matrix display commonly uses a 5×7 format for one capital letter. This article also gives worked examples of capital letters (A-Z), lower-case letters (a-z) and Arabic numerals (0-9) on a 5×7 dot matrix. Other common formats include 5×9, 7×5, 3×5 and 4×6.

Can a dot matrix display show Traditional Chinese?

Yes. The smallest dot matrix that can show most Chinese characters is 16×16 . The more dots, the more complete the character detail. This article compares 16×16, 24×24 and 36×36 dot matrices rendering different typefaces.

Why choose a dot matrix display in product design?

A dot matrix display costs far less than an LCD screen. In applications with a tight budget that still need to show simple information, it is a common choice.

How do I get help integrating a dot matrix display into my product?

If you need standard dot matrix parts, or want to combine them with other kinds of LED display, contact OPTO PLUS LED through the contact form or by email at sales@opledtw.com.

Further reading on dot matrix displays

Keep going with the articles below to cross-check part selection, drive circuit and real application conditions.