Relógios de vidro

Você já se perguntou sobre as desvantagens do vidro safira?

Compreender suas limitações é crucial para tomar decisões informadas sobre seu uso.

Vamos nos aprofundar nas desvantagens do vidro safira e explorar possíveis soluções.

Embora o vidro de safira ofereça muitas vantagens, ele também apresenta diversas desvantagens que podem limitar seu uso em determinadas aplicações.

Some of the main drawbacks of sapphire glass include:

Cost:

The production cost of sapphire glass is higher compared to other types of glass or transparent materials. The process of growing synthetic sapphire crystals is complex and time-consuming, involving high temperatures, specialized equipment, and precise control of growth conditions, which increases production costs. Therefore, sapphire glass is often more expensive than traditional glass or other transparent materials, making its cost-effectiveness lower in some applications.

 

Brittle Nature:

Despite its high hardness, sapphire glass is relatively brittle compared to materials like tempered glass. Under certain conditions, sapphire glass is prone to fracture or breakage, especially when subjected to significant impact or pressure. This brittleness makes sapphire glass more susceptible to damage in applications involving high impact forces or mechanical stress.

 

Difficulty in Processing:

Sapphire glass is more challenging to process compared to other materials. It is a crystalline material that requires specialized cutting, grinding, and polishing techniques, which can be more time-consuming and expensive. Additionally, sapphire glass is difficult to bond or join, which may limit its use in applications requiring bonding or sealing.

 

Limited Size and Thickness:

Due to the challenges in growing large and thick sapphire crystals, the size and thickness of sapphire glass are relatively limited. Compared to traditional glass, sapphire glass typically has smaller dimensions and thinner thicknesses, which may not be suitable for some applications requiring larger or thicker glass components.

Weight:

Sapphire glass has a higher density than traditional glass, meaning it can be heavier for a given size and thickness. This may be a disadvantage in weight-sensitive applications or when designing lightweight devices, where the weight of sapphire glass needs to be considered.

 

More Energy-Intensive Production:

The production of synthetic sapphire crystals used for sapphire glass requires high temperatures and energy-intensive processes, which may result in higher energy consumption and environmental impact compared to other materials. This may be a concern for applications or industries with environmental considerations.

 

Reflectance Without Anti-Reflective (AR) Coating:

Sapphire glass has a relatively high refractive index, which can lead to significant reflection on its surface without proper anti-reflective (AR) coating. This may result in unnecessary reflection or glare in certain applications, such as displays or optical lenses, requiring additional AR coatings to mitigate this issue.

While sapphire glass offers many advantages, it also has several drawbacks, including higher cost, brittleness, processing difficulties, limited size and thickness, weight, more energy-intensive production, and reflectance without AR coating. When evaluating the suitability of sapphire glass for specific applications, these limitations need to be considered, and alternative materials may be preferred based on the requirements and constraints of the application.

 

Amigos que usaram relógios podem ter experimentado este fenômeno: sob a luz solar, a superfície de vidro do relógio reflete severamente a luz, afetando a legibilidade da hora.

A alta refletividade da superfície do vidro dificulta a leitura clara da hora sob luz forte, reduzindo a praticidade do relógio e afetando a experiência do usuário.

Para resolver este problema, é possível aplicar um revestimento ao vidro do relógio utilizando tecnologia de revestimento anti-reflexo para reduzir o reflexo da superfície do vidro e melhorar a legibilidade do relógio sob diferentes condições de iluminação. Ao usar a tecnologia de revestimento AR, a superfície do vidro do relógio pode reduzir efetivamente o brilho e o reflexo, permitindo uma leitura clara do tempo sob várias condições de iluminação.

 

Vamos dar uma olhada na classificação dos revestimentos de vidro de relógio;

Tipos de revestimentos de vidro de relógio

O revestimento de vidro de relógio refere-se à aplicação de uma camada protetora na superfície de um vidro de relógio para aumentar sua durabilidade, resistência a arranhões e desempenho geral. Este revestimento é normalmente aplicado usando técnicas avançadas, como deposição física de vapor (PVD) ou deposição química de vapor (CVD). O objetivo do revestimento do vidro de relógio é melhorar as propriedades da superfície do vidro, tornando-o mais resistente a arranhões, manchas e outras formas de danos que podem ocorrer durante o uso diário.

Existem vários tipos de revestimentos utilizados na relojoaria:

• Revestimento anti-reflexo （Revestimento AR）: Este tipo de revestimento é aplicado para reduzir o brilho e os reflexos no vidro do relógio, melhorando a visibilidade e a legibilidade, especialmente em condições de muita luz.
• Revestimento resistente a arranhões: Este revestimento foi concebido para tornar o vidro do relógio mais resistente a riscos, garantindo que mantém a sua clareza e aparência ao longo do tempo.
• Revestimento anti-impressão digital: Este revestimento ajuda a repelir impressões digitais e manchas, mantendo o vidro do relógio limpo e livre de marcas indesejadas.
• Revestimento repelente à água: Alguns vidros de relógio são revestidos com uma camada repelente à água para melhorar a resistência à água e evitar que gotas de água grudem na superfície.
• Revestimento de proteção UV: Este tipo de revestimento ajuda a proteger o vidro do relógio dos efeitos nocivos da radiação ultravioleta (UV), que pode causar descoloração e degradação ao longo do tempo.

No geral, o revestimento do vidro do relógio desempenha um papel crucial na melhoria do desempenho e da longevidade de um relógio, garantindo que ele permaneça em ótimas condições por muitos anos.

O revestimento mais comumente usado para vidro de relógio é o revestimento AR.

O que é o revestimento AR no vidro do relógio?

Vamos dar uma olhada na classificação dos revestimentos de vidro de relógio.

Everyone knows that any glass will produce glare, including flat and curved glass. Therefore, like many optical instruments’ lenses (including eyeglass lenses), coating treatment is needed on the glass to reduce glare and increase transmittance. Especially for watches with relatively large diameters and curved glass, additional coating treatment is required.

Entre os materiais de filme óptico disponíveis, quanto maior o índice de refração, mais forte será o brilho. O fluoreto de magnésio (MgF2) tem o menor índice de refração, apenas cerca de 1,38, que é muito inferior ao índice de refração do vidro comum e ainda inferior ao do vidro safira. Portanto, usar fluoreto de magnésio como material para revestir o vidro dos relógios pode reduzir a refletância da luz de 4% para 1,8%.

O revestimento anti-reflexo, também conhecido como revestimento AR, é uma fina camada de material revestido na superfície do vidro, usando a mais avançada tecnologia de revestimento por pulverização catódica de magnetron internacionalmente para revestir uma camada de filme anti-reflexo na superfície do vidro temperado comum.

Os revestimentos AR (antirreflexo) podem ser aplicados não apenas ao vidro safira, mas também a outros tipos de superfícies de vidro, como vidro mineral ou vidro orgânico. A principal função do revestimento AR é reduzir o reflexo da luz e melhorar a transmitância da luz, aumentando assim a clareza visual.

Este revestimento é particularmente útil para quem precisa ler relógios com clareza sob quaisquer condições de iluminação. O revestimento AR torna as cores transmitidas através do vidro mais vivas e realistas.

Portanto, o efeito do revestimento do vidro do relógio de safira será melhor. Especialmente para relógios com diâmetros relativamente grandes e vidro curvo, é necessário um tratamento de revestimento adicional.

Nota: O revestimento não pode eliminar completamente o brilho, mas apenas reduzi-lo.

O vidro tratado com revestimento apresentará uma leve cor roxo-azulada.

Existem vários compostos disponíveis para aplicação em vidro de relógio, e esses compostos diferem em desempenho de AR, durabilidade e legibilidade. Por exemplo, alguns filmes antirreflexo podem dar ao vidro uma leve tonalidade azulada.

Some watches will mark to indicate that the watch glass has been coated, such as Omega watches. On the watch card or tag, a circle with the letter “A” inside indicates that the watch glass has been coated, while “AA” indicates that both sides of the watch glass have been coated. Watches usually have many reflective spots, including the case, dial, hands, and are either shiny gold or shiny silver. Therefore, coating is also one of the measures to make it more convenient to wear watches. The coating on the watch glass is not as obvious as that on camera lenses, and it is often difficult to detect.

O revestimento antirreflexo é uma função importante dos relógios e há uma diferença significativa entre relógios com e sem revestimento antirreflexo. Além disso, pode melhorar a aparência estética da lente, tornando-a mais clara e transparente.

 

A história do revestimento AR em vidro de relógio

A história do revestimento AR em vidro de relógio remonta ao final do século XIX, quando o conceito foi descoberto pela primeira vez por Lord Rayleigh em 1886. Ele observou que o vidro ligeiramente manchado permitia a passagem de mais luz em comparação com o vidro novo, que refletia mais luz.

No entanto, foi apenas em meados do século XX que foram feitos avanços significativos no desenvolvimento e aplicação de revestimentos anti-reflexos em vidros de relógios. Em 1935, o cientista soviético Olexander Smakula aperfeiçoou a tecnologia para criar e aplicar revestimentos antirreflexos em lentes ópticas, o que lançou as bases para novos desenvolvimentos na área.

No final da Segunda Guerra Mundial, a indústria da aviação já havia adotado revestimentos antirreflexos para relógios de piloto. Os pilotos que voavam acima das camadas de nuvens frequentemente enfrentavam o brilho intenso do sol, dificultando a leitura dos relógios. Os revestimentos antirreflexos tornaram-se essenciais para melhorar a legibilidade nessas condições, levando ao seu uso generalizado em relógios de aviação.

Desde então, os avanços nos materiais e nas técnicas de fabricação permitiram a ampla adoção de revestimentos AR na indústria relojoeira. Hoje, os revestimentos AR são um recurso padrão em muitos relógios de alta qualidade, oferecendo melhor legibilidade e apelo estético ao reduzir o brilho e os reflexos no vidro do relógio.

 

Quantos tipos de revestimento AR existem para vidros de relógio?

O revestimento AR no vidro do relógio consiste principalmente em dois tipos:

• Revestimento dupla face: O revestimento é aplicado em ambos os lados do vidro do relógio, melhorando os efeitos antirreflexos, mas sendo menos durável devido à suscetibilidade do revestimento externo a arranhões.
• Revestimento unilateral: O revestimento é aplicado apenas em um lado do vidro, resolvendo parcialmente os problemas de reflexão, mas reduzindo a capacidade antirreflexo.

Além desses dois métodos, há também o revestimento pontual, como visto nos relógios Rolex Oyster, onde a lupa da data é revestida. Esta abordagem garante efeitos anti-reflexos e está localizada na parte interna, minimizando riscos de danos.

Algumas marcas sofisticadas também podem aplicar um revestimento antirreflexo na parte traseira transparente da caixa ou na área de movimento para reduzir a interferência da luz. No geral, existem vários métodos de revestimento AR para vidros de relógio, cada um com seus prós e contras. A escolha do método de revestimento depende das necessidades práticas e dos ambientes de uso.

Na indústria relojoeira, os métodos de revestimento para vidros de relógios são geralmente divididos em dois tipos: revestimento dupla-face e revestimento unilateral. Para melhorar ainda mais a transmissão da luz, múltiplas camadas de revestimento podem ser aplicadas em ambos os lados do vidro.

Ambos os métodos de revestimento têm vantagens e desvantagens.

O revestimento frente e verso envolve a aplicação de revestimento em ambos os lados do vidro, o que aumenta a eficiência da AR, mas é menos durável porque o revestimento externo é propenso a arranhões.

O revestimento unilateral cobre apenas um lado do vidro, o que evita problemas de reflexão, mas reduz a capacidade antirreflexo.

Além desses dois métodos, há também o revestimento localizado. Por exemplo, os relógios Rolex Oyster geralmente não têm revestimento nos lados interno e externo do espelho, mas a lupa da data é revestida.

A razão para esta operação é provavelmente devido à consideração da Rolex sobre a durabilidade do revestimento. Os relógios Rolex são conhecidos por sua precisão e durabilidade. Embora o espelho possa refletir a luz, é prático desde que você evite a luz direta. Apenas revestir a janela de exibição da data faz sentido porque ela é pequena e curva e, sem antirreflexo, é difícil ver claramente, causando interferência significativa. Além disso, o revestimento do Rolex é feito na parte interna onde a lupa e o espelho são colados, área que não está sujeita a arranhões ou danos.

É claro que algumas marcas sofisticadas também podem aplicar um revestimento antirreflexo na parte traseira transparente da caixa ou na área de movimento para reduzir a interferência da luz. Isso ajuda a evitar a degradação do óleo lubrificante devido à luz que afeta a operação do movimento.

Vantagens do revestimento AR de vidro de relógio:

Essa tecnologia tem sido amplamente aplicada na indústria relojoeira, mas também tem seus prós e contras.

Vantagens:

• Durabilidade aprimorada: O vidro revestido aumenta a dureza da superfície do relógio, melhorando assim a sua durabilidade.
• Resistência a arranhões: O vidro revestido evita com eficácia arranhões na superfície do relógio, preservando o apelo estético do relógio.
• Anti-reflexo: O vidro revestido reduz os reflexos na superfície do relógio, tornando-o mais claro e mais visível à luz solar.
• Resistência a manchas: O vidro revestido evita a contaminação da superfície do relógio, facilitando a limpeza.

 

Desvantagens do revestimento AR de vidro de relógio:

• Propenso a arranhões: Embora o vidro revestido aumente a dureza da superfície do relógio, ainda é suscetível a arranhões, especialmente após uso prolongado. Embora a superfície do vidro safira possa permanecer intacta se for arranhada, o revestimento pode estar sujeito a arranhões visíveis.
• Suscetível à descamação: O vidro revestido tem tendência a descascar, especialmente sob exposição prolongada a vibrações ou substâncias como água do mar, suor, água quente ou produtos químicos. Portanto, a durabilidade é uma preocupação.
• Não adequado para mergulho: O vidro revestido não é adequado para mergulho, pois não suporta a pressão da água em alta pressão.
• Desbotamento da cor: O vidro revestido pode mudar de cor ao longo do tempo devido à exposição prolongada à luz solar, afetando o apelo estético do relógio.
• Fácil desgaste: TO revestimento anti-reflexo externo no vidro do relógio é propenso a desgaste, tornando-se visivelmente aparente quando arranhado devido à diferença de reflexão entre as áreas revestidas e arranhadas.
• Sensibilidade à umidade: Os relógios armazenados por um período prolongado devem ser protegidos da umidade. A exposição a um ambiente úmido pode levar à formação de mofo na superfície do vidro e danificar a camada de revestimento. Portanto, é fundamental utilizar dessecantes nas caixas de relógios e evitar ambientes úmidos.

Resumo:

As vantagens da tecnologia de vidro revestido de relógio são significativas, pois aumenta a durabilidade, a resistência a arranhões, as propriedades antirreflexo e a resistência a manchas do relógio. No entanto, também apresenta algumas desvantagens, como suscetibilidade a arranhões, fácil descamação, inadequação para mergulho e suscetibilidade à descoloração. Portanto, ao comprar um relógio, é necessária uma consideração cuidadosa.

 

O processo de produção do revestimento AR envolve várias etapas:

1. Limpe a superfície da safira para remover qualquer sujeira, poeira ou óleo que possa afetar a qualidade do revestimento.
2. Aplicar o revestimento pelo processo de deposição física de vapor (PVD), onde o vidro é colocado em uma câmara de vácuo e uma fina camada de material é depositada na superfície por pulverização catódica.
3. Certifique-se de que o processo de revestimento seja realizado em um ambiente controlado para obter um revestimento uniforme e uma espessura consistente em toda a lente.
4. Após o revestimento, retire o vidro da câmara de vácuo e inspecione-o para garantir que não haja defeitos no revestimento.
5. Endureça o revestimento expondo o vidro à luz ultravioleta (UV), que ativa reações químicas no revestimento, tornando-o mais duro e durável.

É importante observar que, como qualquer tratamento de superfície, pode ser suscetível a arranhões e exigir manutenção periódica. Para resolver isso, uma camada de revestimento de safira pode ser aplicada sobre o revestimento AR.

Qual é a cor do revestimento AR do vidro do relógio?

O revestimento AR no vidro do relógio é normalmente transparente, mas em alguns casos pode ter uma tonalidade colorida, como azul, verde ou roxo. No entanto, seja transparente ou colorido, não é facilmente perceptível, e os revestimentos coloridos geralmente só são discerníveis em ângulos específicos de luz.

Pensamento final:

Concluindo, a aplicação do revestimento AR no vidro de relógio é um avanço significativo na tecnologia relojoeira, oferecendo vantagens e desvantagens. Embora melhore a durabilidade, a resistência a arranhões e a visibilidade sob várias condições de iluminação, também está sujeito a arranhões, descascamento e descoloração com o tempo. Portanto, ao escolher um relógio, é essencial pesar estes fatores e considerar o ambiente de utilização pretendido. No geral, o revestimento AR desempenha um papel crucial na melhoria do desempenho e da longevidade dos relógios, contribuindo para uma melhor experiência do utilizador.

In the watch industry, why do most luxury watches choose to use sapphire crystal glass? Is sapphire crystal glass truly a symbol of high-end watch quality?

Why do people generally believe that watches with sapphire crystal glass are of higher quality?

We aim to unravel the performance and various differences between sapphire crystal glass and mineral glass through comparative analysis, providing wise selection advice for watch enthusiasts.

We first take a look at the three most common types of watch crystal materials:

1. Sapphire Glass
2. Mineral Glass (Inorganic Glass)
3. Acrylic Glass (Organic Glass)

We’ve covered watch glass in full before:

Tudo o que aprendi sobre relógios e óculos na fábrica de relógios

The Differences between Sapphire Watch Glass, Mineral Glass and Acrylic Glass?

The differences between these glass materials are as follows:

Acrylic Glass

Acrylic glass, commonly known as acrylic or organic glass, is a type of material used for watch crystals. It has a softer texture and higher malleability. In the past, many watches used this material, including antique watches found in the market today.

Pros:

• Excellent elasticity and resistant to shattering, often referred to as safety glass.

Cons:

• Susceptible to scratching and slightly lower transparency.

Reasons for Choosing:

• Low cost, scratches can be polished by a watchmaker without the need for replacement. If scratches are too deep, the crystal can be replaced inexpensively.

Mineral Crystal Glass

Mineral crystal glass, also known as Hardlex or Acrylic Crystal, is a type of glass reinforced with minerals. It was developed due to the scarcity of natural crystals.

Pros:

• High hardness, excellent transparency, clear and bright appearance.

Cons:

• Higher unit price compared to Acrylic Glass.

Reasons for Choosing:

• Moderate cost, high hardness, scratch-resistant, clear and transparent with no bubbles or watermarks, and it possesses piezoelectric properties, offering special health benefits.

 

Sapphire Crystal Glass

Sapphire crystal glass is a crystalline surface made from artificially compressed sapphire crystals, which are aluminum oxide crystals with impurities like iron oxide and titanium oxide removed. Chemically, Acrylic Sapphire is identical to natural sapphire and does not possess a “blue” color.

Pros:

• High density and scratch resistance, with hardness second only to diamond.
• Excellent light transmission, low friction, high temperature resistance, and superior durability compared to mineral crystal and Acrylic Glass .

Cons:

• Not shock-resistant, vulnerable to impact, pressure, or drops, which may lead to cracks upon impact.

Which Material is Superior?

In terms of hardness and abrasion resistance: Acrylic Glass < Mineral crystal glass < Sapphire crystal glass.

Each has its advantages: Acrylic Glass is less likely to break and can be polished; mineral crystal glass has moderate scratch resistance and stronger resistance to vertical impacts than sapphire crystal glass; sapphire crystal glass, despite its high hardness, is prone to breakage and incurs higher repair costs.

For high-end customers, sapphire crystal glass is recommended due to its special physical and chemical properties, high hardness (Mohs scale 9), superior wear resistance, and resistance to corrosion.

Lower-end watches often use organic glass, also known as acrylic, which despite being prone to scratches, is resilient and widely used in low-end watches.

Each material has its advantages and is chosen based on factors such as cost, scratch resistance, transparency, and durability.

Watch Glass: Sapphire Glass VS Mineral Glass

Sapphire crystal glass and mineral glass are two common materials used in watchmaking and the production of certain optical components. Here are some key differences between them:

1. Material Composition:
   • Sapphire Crystal Glass: Made from Acrylic Sapphire, a crystalline form of aluminum oxide. It is highly transparent and scratch-resistant.
   • Mineral Glass: Composed of various minerals, typically a hardened form of glass. It is less scratch-resistant compared to sapphire crystal.
2. Hardness:
   • Sapphire Crystal Glass: One of the hardest materials（Mohs: 9), second only to diamonds ( Mohs: 10). It is highly resistant to scratches.
   • Mineral Glass: While hardened, it is not as scratch-resistant as sapphire crystal and may show signs of wear over time.

Generally speaking, sapphire crystal is three times stronger than mineral glass and 20 times stronger than plastic glass.

1. 1. Resistência a arranhões:
      • Sapphire Crystal Glass: Extremely resistant to scratches, making it ideal for applications where durability is crucial.
      • Mineral Glass: Can still resist scratches to some extent, but it is more prone to visible scratches compared to sapphire crystal.
   2. Clarity:
      • Sapphire Crystal Glass: Offers excellent transparency and clarity, allowing for a clear view of the dial and components underneath.
      • Mineral Glass: Generally provides good clarity but may have some distortion compared to sapphire crystal.
   3. Cost:
      • Sapphire Crystal Glass: Typically more expensive to produce, which can contribute to higher overall product costs.
      • Mineral Glass: Generally more cost-effective, making it a popular choice for more budget-friendly options.
   4. Weight:
      • Sapphire Crystal Glass: Heavier than mineral glass due to its density.
      • Mineral Glass: Lighter in comparison.
   5. Applications:
      • Sapphire Crystal Glass: Commonly used in high-end watches, camera lenses, and other applications where scratch resistance is crucial.
      • Mineral Glass: Found in a wide range of watches, eyeglasses, and other optical instruments.
   6. Shape:
      • Sapphire Crystal Glass: Sapphire crystal glass is limited to flat only.
      • Mineral Glass: Mineral crystal glass can be manufactured in a variety of forms.

Watch Glass: Sapphire Glass VS Acrylic Glass

In modern watches, the most commonly used material for the watch crystal is sapphire crystal glass. However, historically, watches have not always been made exclusively with this material as the watch crystal.

Take Rolex for example, modern Rolex watches have all switched to sapphire crystal glass, but in earlier times, before the end of the last century, Rolex also used plastic material acrylic for making the watch crystal. Acrylic material had two main advantages:

• Impact Resistance: Acrylic crystal, also known as plastic glass, is a reliable and durable material, especially resistant to impact. When tapped with a fingertip, it produces a clear and loud sound.
• Less Likely to Shatter: If an acrylic crystal breaks, it typically does not shatter into small fragments. As a result, there is almost no risk of damaging the watch dial, hands, or internal movement.

Of course, acrylic crystal is not without its drawbacks. Its biggest disadvantage is that it is not scratch-resistant and does not provide sufficient water resistance.

Acrylic material is a polymer composed of polymethyl methacrylate. In the era before sapphire crystal material became widespread, acrylic was the mainstream material used by various watch manufacturers.

The reason watchmakers favored it was because it offered a certain degree of impact resistance and protection. Even if an acrylic crystal were to break from a strong impact, it was less likely to shatter into fine particles, minimizing the impact on the watch dial.

However, acrylic crystals gradually began to be replaced because they had some noticeable drawbacks. For example, they had lower hardness and were prone to scratching, resulting in visible scratches on the crystal.

Additionally, acrylic crystals had poorer transparency, giving watches a slightly hazy appearance. Moreover, from a manufacturing perspective, plastic glass tended to be thicker, adding weight to the watch and making it less suitable for producing ultra-thin watches.

Today, well-known trendy sports watches like Casio’s G-SHOCK still use acrylic crystal glass. However, acrylic crystals have seen a resurgence in some popular sports watches today due to their impact resistance and less likelihood of shattering, and the lack of transparency does not significantly affect watches with LED screens.

Rolex gradually transitioned to technologically advanced sapphire crystal glass in the 1980s. This material is primarily composed of aluminum oxide (Al2O3), which is not a natural gemstone but rather synthetically produced. This allowed watch manufacturers to enjoy the benefits similar to natural sapphire without a significant increase in production costs.

The benefits of sapphire crystal glass lie in its high hardness, reaching a Mohs hardness of 9, which is just slightly lower than that of diamond. This means that it is not easy to scratch sapphire crystal, making it resistant to scratches.

Additionally, sapphire crystal glass has better transparency, providing a bright and clear appearance to the watch. Furthermore, it can be processed to a thinner degree, allowing for a reduction in the overall thickness of the watch.

However, these advantages do not necessarily mean that sapphire crystal glass is superior to acrylic glass. Along with its high hardness comes the risk that sapphire crystal may shatter more easily upon strong impact. In such cases, it can pose a threat to the watch dial and movement structure, especially for watches with hollowed-out or open-face designs. Therefore, while sapphire crystal glass may be highly durable, if it does shatter, the damage to the watch can be more severe.

But, Why do various brands still choose sapphire crystal material and abandon acrylic glass material?

The answer is not hard to guess. Because in daily wear, the chance of the watch being lightly scratched by external factors is greater than the chance of the watch being strongly impacted. Additionally, the technology of producing sapphire crystal glass has become very popular and does not significantly increase costs. Therefore, switching to sapphire crystal glass has become a better choice for watch factories.

Apart from these two materials, watch factories also use mineral glass to make watches, which is somewhat between acrylic glass and sapphire crystal glass. Although watches using mineral glass are not very common nowadays, they still occasionally appear in the works of some brands. However, in terms of prevalence, sapphire crystal is still the mainstream material in the watch industry.

Mineral glass is mostly used in some classic retro watches that require special crystal shapes to complement the overall style of the watch, such as single-domed and double-domed crystals. Single-domed crystals enhance the magnification effect on the dial, while double-domed crystals create a more ideal and prominent depth effect on the dial.

Whether it’s a single-domed or double-domed crystal, it adds a retro feel to the overall design of the watch, making the dial visually compelling and easy to read. This type of crystal not only achieves a three-dimensional visual effect with its convex shape but also enhances the magnification effect of the dial elements, allowing for thinner and more delicate watch designs.

Why use Mineral glass instead of Sapphire crystal glass?

This is because some watch crystals, not flat, have protruding edges that are prone to being knocked. Sapphire is also very fragile, so using regular glass is more reliable in comparison. Of course, to address the issue of scratch resistance on the crystal surface, some watch manufacturers also apply a sapphire coating to acrylic glass to achieve its scratch-resistant properties. Additionally, mineral acrylic glass is much cheaper than sapphire.

 

Price Comparison on Sapphire vs Mineral and Acrylic Watch Glass

Is sapphire expensive? In reality, with the widespread application of sapphire crystal glass, its market price has become very affordable. Nowadays, many popular watch brands on the market use sapphire crystal glass. However, compared to mineral glass and acrylic, sapphire crystal glass is relatively expensive.

 

FAQ

What is Mineral Watch Glass?

Mineral glass, also known as acrylic crystal, is a commonly used material in watchmaking. It is an ordinary crystal glass that undergoes polishing and hardening processes. Unlike sapphire crystal glass, mineral glass has a lower hardness. It was developed due to the scarcity of natural crystals, which couldn’t meet the demands of the industry. Its high transparency makes it suitable for various crafts, contributing to its popularity. The process of making mineral glass involves melting silica and lead oxide, resulting in a shiny surface with clarity achieved through advanced polishing technology.

Mineral-strengthened glass has a hardness of 7, making it resistant to scratches from most daily objects like knives and steel saw blades, which typically have lower hardness levels. However, it’s important to be cautious as sand grains, which also have a hardness of 7, can scratch the surface. Choosing a sapphire surface is preferable if possible. Sapphire surfaces, created by coating the glass with a layer of synthetic sapphire, offer a surface hardness of 9, making them highly resistant to scratches from anything except diamond and sapphire. Additionally, they are resistant to damage from sand grains.

Are Watches with Mineral Glass Good?

Answer 1:

Mineral crystal glass, also known as Acrylic Crystal, is a type of material used in watches. It is typically ordinary crystal glass that is polished and hardened, although its hardness is lower than that of sapphire crystal. This glass was developed due to the scarcity and difficulty in mining natural crystals, which couldn’t meet the demand. Because of its high transparency, it is popular for various crafts. Mineral crystal glass is crystalline with a high hardness (Mohs hardness of 7), good thermal conductivity, and a cool sensation when touched. It appears clear and bright against light, without small bubbles or watermarks, making it relatively expensive.

Answer 2:

The scratch resistance of mineral-strengthened glass is slightly inferior to sapphire glass, as its hardness is about 7, while sapphire glass has a hardness of 9. However, mineral-strengthened glass has higher overall compressive strength than sapphire glass. Therefore, all deep diving watches (deeper than 200 meters) use mineral-strengthened glass for their watch glass. Although sapphire glass has excellent scratch resistance, its thickness is only 5 micrometers, and its overall compressive strength is lower than that of mineral-strengthened glass, rendering it unsuitable for deep diving watches.

What is the Anti-glare Watch Glass?

In simple terms, anti-glare coating is a multi-layer film electroplated onto the lens to prevent light reflection. It’s commonly used in professional aviation, diving watches, or watches with large mirror curvature. It can be divided into double-layer anti-glare glass and single-layer anti-glare glass. The difference lies in the former being electroplated on both sides of the lens, while the latter is only coated on the inner side of the glass. The effectiveness of both types is similar.

The main function of anti-glare coating is to prevent glare and reflection, enabling better readability. When viewed from the front, it may appear as if it’s not mounted on the mirror, but from a specific angle, it reflects a layer of bluish color, similar to the eyes on the coating.

Pensamento final:

Ultimately, the choice between sapphire crystal glass, mineral glass and Acrylic glass depends on the specific requirements of the application, budget considerations, and the desired level of durability and scratch resistance. And it’s not the sapphire crystal that makes the watch better.

 

The watch glass is an inconspicuous character, so no one wants to know more about it, but did you know that it is important? Because if you’re not careful, you’ll match your watch glass wrong and it’ll be scrapped.

The Watch glass is divided into mineral glass, sapphire glass, and acrylic glass; it also has a flat, single-dome, and double-dome shape, and Cold-coated glass;

Watch Glass is generally provided by the case factory together because the case factory will be equipped with glass according to the customer’s water resistance requirements.

Do you know the advantages and disadvantages of each glass and want to know more? Follow our steps.

Watch Glass Function

The watch crystal, the clear lens on the watch’s exterior, is also called the watch glass and is used to protect the watch’s dial.

Types and Shapes of Watch Glasses

According to the material, the watch glass can be divided into synthetic glass, mineral crystal glass, and Sapphire Glasses.

3 Types of Watches Glasses:

 

1. Mineral glass
2. Sapphire
3. Acrylic Crystal

The main component of Mineral glass is quartz ore, in addition to a small amount of limestone, sodium carbonate, and other fusing agents, through high-temperature firing to turn it into a fluid, and then made into a variety of glass products.

Sapphire glass usually refers to synthetic sapphire, the main component of which is aluminum oxide (Al2O3), the composition of which is close to that of natural sapphire。

Another name for Acrylic glass is plexiglass, and acrylic is plastic.

 

Shapes of The Watches Glasses?

1. Flat Glass

   

   It’s all flat like parallel lines.

2. The Single Dome-shaped glass

   

This shape is a convex surface and a flat bottom.

3. Double Domed Glass

   

   

This shape is the face convex and bottom convex; it looks Like the pot we used for cooking.

 

4. Cold-coated Glass

It looks like the Pod lid.

 

Cons and Pros of Different Types of Watches Glasses?

Most people searched “Why use Sapphire glasses for watches?”

the sapphire glass is of good hardness, not easy to scratch, and not easy to break.

So let’s see their advantages and disadvantages of them.

Cons and Pros of Them

 

• Sapphire crystal: it’s physically and chemically stable. The hardness is lesser than the diamond. It can resist scratching, aging, corrosion, etc., but it is fragile. The Sapphire glass mirror watch is very transparent; You can clearly see the dial.

(Generally used for high-grade watches)

• Acrylic Crystal: that is, synthetic glass, commonly known as acrylic, easy to scratch, but good toughness, not easy to break. 98% of the customers won’t use this as the watch’s glasses. Once a long time, this material crystal will be oxidized and the cracks will appear. Also, it needs a larger order quantity. If you are selling plastic watches, some can use them.

(Mostly used for low-end watches)

• Mineral glass: better resistance to friction but the ability to resist vertical blows than sapphire glass. Therefore, military watches mostly use it as a crystal.

(For low-end watches)

 

How to Identify the Three Kinds of Glasses?

First, you can finger-tap the mirror surface and listen carefully to the sound. Acrylic mirrors will make a plastic-like sound, while the sound of glass then thicker.

Second, you can judge from the weights that the acrylic crystal is the lightest, and the sapphire mirror is the heaviest.

Since sapphire conducts heat very well, when you touch it with your hand, there will be a feeling of coldness.

And sapphire glasses are much smoother than the other two materials; you will feel more smothered when you touch them.

If you put a drop of water on the sapphire mirror, it will still be a drop of water, No slipping away, while on the other material, the water drops will spread out.

 

Method of Replace the Watch Glass

The glass is the most prominent part of the watch and is subject to the most friction and impact. Because of its material and particular function, the glass is one of a watch’s most easily damaged parts.

If the glass is lost, broken, or cracked, it must be replaced according to the original specifications.

When replacing a watch glass, the main thing to consider is the outer and inner diameter of the glass, The inner diameter should fit the tight ring, and the outer diameter should fit the case tightly.

When the two conditions are met, you can change the glass, which isn’t related to the watch’s brand.

Among these two accessories, the outer diameter is the most important, and It does not matter if the inner diameter is a little smaller. Because the tightening ring can be used as an open ring, this does not affect the watch’s glass.

 

How to Assemble Glasses for Watches?

When replacing a watch glass, you can directly fit the watch glass into the case glass slot by hand.

After removing the damaged glass, clean the glass groove of the case, configure a tight ring in the inner opening of the glass, and then put the glass into the case groove.

 

When the inner opening of the glass is equipped with a good tight ring and then put the glass into the case slot, when three-quarters of the glass is already in the case slot, you can use your hand to install the glass.

 

How to choose the glass ring/waterproof ring?

The inside diameter of the water-resistant ring = diameter of the crystal glass
Height of the water-resistant ring: less than the height (thickness) of the white edge of the crystal.
The outer diameter of the waterproof ring is 0~0.2mm larger than the inner diameter of the case.
(It is usually recommended to choose the outer diameter of the waterproof ring is about 0.1-0.2mm larger than the case will be better waterproof)

For example: the diameter of the crystal 29.5mm, case inner diameter 30.2mm

For example, Waterproof ring Optional:
29.5mm inner diameter, thickness 0.35mm, outer diameter is 30.2mm (available, just right, may be a little loose)
29.5mm inner diameter, 0.4mm thick, outer diameter is 30.3mm (recommended)
29.5mm I.D., 0.45mm thick, O.D. is 30.4mm (recommended)

What’s the function of the waterproof ring, You can check this post:

Tips on Deal With A Watch that has Water in it

When three-fourths of the glass is already in the slot, use the four fingers of the left hand to hold the back cover of the case. Press the thumb firmly against the center of the glass.

The right thumb pushes the edge of the glass that the part that does not enter the case recess in the case. It is better to use cover pliers. Using rubber cover pliers can make the glass everywhere evenly stressed, and you can press the edge of the glass into the case groove at once.

However, You must accurately choose the right size of the inner and outer diameter of the glass; otherwise, it will crush the glass.

If not, the glass will be crushed. It means the outer diameter is suitable if you can fit it in. and then installed it on the tight circle with amine cover pliers to press into the table.

 

How to Protect Your Watches Glasses?

When using the watch, try to avoid collision between the watch glass and hard objects or scratching the watch glass by sharp objects to prevent damage. Also, check the watch strap periodically so that the band does not break and cause the watch to fall to the ground.

Watch glass maintenance: proper cleaning of the watch glass.

sapphire glass single dome

 

If the watch glass is stained with a simple and easy-to-remove stain, you can clean it by yourself and get it back to clean. If your watch is water-resistant and has good water resistance, it is simple to clean the watch with soap and water. Gently brush the watch’s surface with a toothbrush, especially where there are crevices, to clean the dirt inside. But remember, when washing the watch, don’t pull out the crown.

Sometimes you can also coat your sapphire glass with a protection film, because sapphire glass is very hard. Once it breaks, it will break into pieces, it will fall to your dial and damage your watch, if there is a film just like the car window has a film, to a certain extent can protect your watch, but also can make your dial see more clearly.

 

Other Related:

Best Glasses for Watches?

Our suggestion is if you have enough budget, Then use the Sapphire glass, If your budget is not enough, Then use the mineral Glasses.

Watch Glass Cost?

The Cost of mineral and Crystal glass is nearly the same, around 0.15usd-0.5usd. But Sapphire glass is the most expensive one.

Specifications of the Watches Glasses?

The Glass’s diameter is based on the size of the watch, The thickness of glasses is made according to the water resistance.

If for 5ATM, the thickness is mostly 1.2-1.5mm,

If for 10ATM, the thickness will be over 2.0mm,

If for 20ATM, the thickness will be over 3.0mm.

 

Conclusion:

Although glass is a very simple thing, there is still a lot to know need to know it. What else do you want to know? You can leave a comment.